研究者データベース

相場 慎一郎(アイバ シンイチロウ)
地球環境科学研究院 環境生物科学部門 陸域生態学分野
教授

基本情報

所属

  • 地球環境科学研究院 環境生物科学部門 陸域生態学分野

職名

  • 教授

学位

  • 博士(地球環境科学)(1997年12月 北海道大学)

ホームページURL

J-Global ID

研究キーワード

  • 植物生態学   森林生態学   

研究分野

  • ライフサイエンス / 生態学、環境学

職歴

  • 1999年10月 - 2019年10月 鹿児島大学
  • 1998年01月 - 1999年09月 独立行政法人日本学術振興会

所属学協会

  • 日本熱帯生態学会   アメリカ生態学会   イギリス生態学会   日本生態学会   

研究活動情報

論文

  • Mana Mukai, Taiki Mori, Shin ichiro Aiba, Kanehiro Kitayama
    Ecological Research 2020年 [査読有り][通常論文]
     
    © 2020 The Ecological Society of Japan Soil nitrogen (N) mineralization is the product of the soil biochemical properties and temperature. It is known that in situ soil N mineralization monotonously decreases with increasing elevation along a mountain slope reflecting decreasing air temperature. However, inherent soil biochemical properties (quality of organic matter and soil microbe profile) may also affect the decreasing soil N mineralization. We analyzed how temperature and inherent soil organic matter quality affect soil N mineralization rates using the elevation gradient of Yakushima with a “common-site” approach with multiple incubation temperatures. We collected topsoils from seven forests at seven different elevations along 170–1,550 m a.s.l and incubated them under each of four temperatures at 15, 20, 25 and 30°C for 10 days in the lab. We also measured soil microbial biomass and heterotrophic soil respiration rates. Net soil N mineralization rates incubated at 15, 25 and 30°C decreased significantly linearly with increasing elevation of the origin of the soil samples at the same temperature and the intercepts of the regression lines were similar among incubation temperatures 15, 20 and 25°C. These results indicated that in situ net N mineralization rates are regulated primarily by quality of soil organic matter in our sites. Soil phenolics/N ratios increased with increasing elevation reflecting the vegetation shift along elevation and significantly negatively correlated to net soil N mineralization rates incubated at 15°C. We conclude that elevationally differentiated vegetation and associated inherent soil properties exert strong influences on net soil N mineralization rates on Yakushima Island.
  • Mana Mukai, Yoshimi Sawada, Kanehiro Kitayama, Shin ichiro Aiba
    Journal of Forest Research 24 1 35 - 41 2019年01月02日 [査読有り][通常論文]
     
    © 2018, © 2018 The Japanese Forest Society. We measured the productivity and morphological traits of fine roots in seven forests between 170 and 1550 m along an elevation gradient on Yakushima Island, Japan. Yakushima Island is continuously covered by forests ranging from the lowland evergreen broad-leaved forests below 1000 m to the upland evergreen coniferous forests above. Mean annual temperature decreases linearly and soil nutrient availabilities (both N and P) also decrease with increasing elevation. We employed an in-growth core method to determine fine-root productivity. Mean fine-root biomass ranged from 0.123 to 0.297 kg m −2 in the lowland broad-leaved forests and from 0.092 to 0.097 kg m −2 in the upland coniferous forests. Mean fine-root productivity ranged from 0.063 to 0.173 kg m −2  yr −1 in the lowland broad-leaved forests and from 0.033 to 0.044 kg m −2  yr −1 in the upland coniferous forests. Both mean fine-root biomass and mean fine-root productivity were significantly greater in middle-elevation broad-leaved forests than in the lower broad-leaved or the higher coniferous forests. Fine-root turnover rate tended to be lower and mean specific root length (SRL) tended to be higher in the coniferous forests. In the upland coniferous forests, trees may adapt to nutrient limitation and/or cooler climate by increasing the life span and SRL of fine roots instead of increasing carbon allocation to fine roots, thereby decreasing fine-root productivity. Fine-root dynamics along the elevational gradient on Yakushima reflected the species shift from broad-leaved to coniferous trees rather than the monotonous reduction of temperature and nutrient availability.
  • Thomas Ibanez, Gunnar Keppel, Cláudia Baider, Chris Birkinshaw, Heike Culmsee, Susan Cordell, F. B.Vincent Florens, Janet Franklin, Christian P. Giardina, Thomas W. Gillespie, Melinda Laidlaw, Creighton M. Litton, Tara G. Martin, Rebecca Ostertag, Narayanaswamy Parthasarathy, Richard Randrianaivo, Miramasoandro Randrianjanahary, Muthu Rajkumar, Ladan Rasingam, Fidy Ratovoson, Ludovic Reza, Lawren Sack, Shin Ichiro Aiba, Edward Webb, Timothy J.S. Whitfeld, Runguo Zang, Philippe Birnbaum
    Global Ecology and Biogeography 27 4 474 - 486 2018年04月 [査読有り][通常論文]
     
    © 2018 John Wiley & Sons Ltd Aim: To determine the role of regional forcing on plot-level species diversity and composition, and to quantify the relative importance of biogeographical and climatic factors in explaining woody plant diversity and composition at the local-, island- and archipelago-scale. Location: Forty-one tropical islands of the Indo-Pacific region from Madagascar to Hawai‘i Island. Methods: We analysed the diversity and composition of tropical woody plant communities located across 113 plots, 41 islands and 19 archipelagos. We used generalized linear mixed-effects models and generalized dissimilarity models to determine the role of regional forcing at the island and archipelago scale and to assess the relative importance of biogeographical (area and isolation of islands or archipelagos, geographical distance between plots) and climatic factors in explaining differences in local diversity and composition (species turnover). Analyses were conducted at different geographical scales (local, island and archipelago) and taxonomic levels (species, genus and family). Results: Variation in local (plot-level) diversity (as species density, the number of species per 100 woody plants) was primarily explained by island and archipelago identity. Maximum species density was positively correlated with the area of an island (or archipelago) and negatively correlated with the isolation of an archipelago. Local climatic variability was also a significant predictor of species density, but less important than regional forcing. Climate variables explained < 20% of the variation in species turnover across all plots. The importance of geographical distance between plots relative to climate in driving species turnover decreased from the species to family level, and from the regional to island level. Main conclusions: Regional forcing was the key driver of local diversity and composition on islands. Island area and archipelago isolation are likely driving local diversity through their effects on the pool of island species. Geographical distance between plots is the main factor explaining species turnover, while at higher taxonomic levels, climatic factors and niche conservatism are the main drivers.
  • J W Ferry Slik, Janet Franklin, Víctor Arroyo-Rodríguez, Richard Field, Salomon Aguilar, Nikolay Aguirre, Jorge Ahumada, Shin-Ichiro Aiba, Luciana F Alves, Anitha K, Andres Avella, Francisco Mora, Gerardo A Aymard C, Selene Báez, Patricia Balvanera, Meredith L Bastian, Jean-François Bastin, Peter J Bellingham, Eduardo van den Berg, Polyanna da Conceição Bispo, Pascal Boeckx, Katrin Boehning-Gaese, Frans Bongers, Brad Boyle, Fabian Brambach, Francis Q Brearley, Sandra Brown, Shauna-Lee Chai, Robin L Chazdon, Shengbin Chen, Phourin Chhang, George Chuyong, Corneille Ewango, Indiana M Coronado, Jurgi Cristóbal-Azkarate, Heike Culmsee, Kipiro Damas, H S Dattaraja, Priya Davidar, Saara J DeWalt, Hazimah Din, Donald R Drake, Alvaro Duque, Giselda Durigan, Karl Eichhorn, Eduardo Schmidt Eler, Tsutomu Enoki, Andreas Ensslin, Adandé Belarmain Fandohan, Nina Farwig, Kenneth J Feeley, Markus Fischer, Olle Forshed, Queila Souza Garcia, Satish Chandra Garkoti, Thomas W Gillespie, Jean-Francois Gillet, Christelle Gonmadje, Iñigo Granzow-de la Cerda, Daniel M Griffith, James Grogan, Khalid Rehman Hakeem, David J Harris, Rhett D Harrison, Andy Hector, Andreas Hemp, Jürgen Homeier, M Shah Hussain, Guillermo Ibarra-Manríquez, I Faridah Hanum, Nobuo Imai, Patrick A Jansen, Carlos Alfredo Joly, Shijo Joseph, Kuswata Kartawinata, Elizabeth Kearsley, Daniel L Kelly, Michael Kessler, Timothy J Killeen, Robert M Kooyman, Yves Laumonier, Susan G Laurance, William F Laurance, Michael J Lawes, Susan G Letcher, Jeremy Lindsell, Jon Lovett, Jose Lozada, Xinghui Lu, Anne Mette Lykke, Khairil Bin Mahmud, Ni Putu Diana Mahayani, Asyraf Mansor, Andrew R Marshall, Emanuel H Martin, Darley Calderado Leal Matos, Jorge A Meave, Felipe P L Melo, Zhofre Huberto Aguirre Mendoza, Faizah Metali, Vincent P Medjibe, Jean Paul Metzger, Thiago Metzker, D Mohandass, Miguel A Munguía-Rosas, Rodrigo Muñoz, Eddy Nurtjahy, Eddie Lenza de Oliveira, Onrizal, Pia Parolin, Marc Parren, N Parthasarathy, Ekananda Paudel, Rolando Perez, Eduardo A Pérez-García, Ulf Pommer, Lourens Poorter, Lan Qie, Maria Teresa F Piedade, José Roberto Rodrigues Pinto, Axel Dalberg Poulsen, John R Poulsen, Jennifer S Powers, Rama Chandra Prasad, Jean-Philippe Puyravaud, Orlando Rangel, Jan Reitsma, Diogo S B Rocha, Samir Rolim, Francesco Rovero, Andes Rozak, Kalle Ruokolainen, Ervan Rutishauser, Gemma Rutten, Mohd Nizam Mohd Said, Felipe Z Saiter, Philippe Saner, Braulio Santos, João Roberto Dos Santos, Swapan Kumar Sarker, Christine B Schmitt, Jochen Schoengart, Mark Schulze, Douglas Sheil, Plinio Sist, Alexandre F Souza, Wilson Roberto Spironello, Tereza Sposito, Robert Steinmetz, Tariq Stevart, Marcio Seiji Suganuma, Rahayu Sukri, Aisha Sultana, Raman Sukumar, Terry Sunderland, Supriyadi, H S Suresh, Eizi Suzuki, Marcelo Tabarelli, Jianwei Tang, Ed V J Tanner, Natalia Targhetta, Ida Theilade, Duncan Thomas, Jonathan Timberlake, Márcio de Morisson Valeriano, Johan van Valkenburg, Tran Van Do, Hoang Van Sam, John H Vandermeer, Hans Verbeeck, Ole Reidar Vetaas, Victor Adekunle, Simone A Vieira, Campbell O Webb, Edward L Webb, Timothy Whitfeld, Serge Wich, John Williams, Susan Wiser, Florian Wittmann, Xiaobo Yang, C Yves Adou Yao, Sandra L Yap, Rakan A Zahawi, Rahmad Zakaria, Runguo Zang
    Proceedings of the National Academy of Sciences of the United States of America 115 8 1837 - 1842 2018年02月20日 [査読有り][通常論文]
     
    Knowledge about the biogeographic affinities of the world's tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world's tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.
  • Lan Qie, Simon L Lewis, Martin J P Sullivan, Gabriela Lopez-Gonzalez, Georgia C Pickavance, Terry Sunderland, Peter Ashton, Wannes Hubau, Kamariah Abu Salim, Shin-Ichiro Aiba, Lindsay F Banin, Nicholas Berry, Francis Q Brearley, David F R P Burslem, Martin Dančák, Stuart J Davies, Gabriella Fredriksson, Keith C Hamer, Radim Hédl, Lip Khoon Kho, Kanehiro Kitayama, Haruni Krisnawati, Stanislav Lhota, Yadvinder Malhi, Colin Maycock, Faizah Metali, Edi Mirmanto, Laszlo Nagy, Reuben Nilus, Robert Ong, Colin A Pendry, Axel Dalberg Poulsen, Richard B Primack, Ervan Rutishauser, Ismayadi Samsoedin, Bernaulus Saragih, Plinio Sist, J W Ferry Slik, Rahayu Sukmaria Sukri, Martin Svátek, Sylvester Tan, Aiyen Tjoa, Mark van Nieuwstadt, Ronald R E Vernimmen, Ishak Yassir, Petra Susan Kidd, Muhammad Fitriadi, Nur Khalish Hafizhah Ideris, Rafizah Mat Serudin, Layla Syaznie Abdullah Lim, Muhammad Shahruney Saparudin, Oliver L Phillips
    Nature communications 8 1 1966 - 1966 2017年12月19日 [査読有り][通常論文]
     
    Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha-1 per year (95% CI 0.14-0.72, mean period 1988-2010) above-ground live biomass. These results closely match those from African and Amazonian plot networks, suggesting that the world's remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997-1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere.
  • 澤田 佳美, 相場 慎一郎, 清野 達之, 北山 兼弘
    日本生態学会誌 = Japanese journal of ecology 67 3 323 - 330 日本生態学会誌編集委員会 2017年11月 [査読無し][通常論文]
  • Kei ichi Okada, Shin ichro Aiba, Kanehiro Kitayama
    Ecological Research 32 2 145 - 156 2017年03月01日 [査読有り][通常論文]
     
    © 2016, The Ecological Society of Japan. We investigated how temperature and nutrient availability regulate fine-root productivity in nine tropical rainforest ecosystems on two altitudinal gradients with contrasting soil phosphorus (P) availabilities on Mount Kinabalu, Borneo. We measured the productivity and the nutrient contents of fine roots, and analyzed the relationships between fine-root parameters and environmental factors. The fine-root net primary productivity (NPP), total NPP, and ratio of fine-root NPP to total NPP differed greatly among the sites, ranging from 72 to 228 (g m−2 year−1), 281–2240 (g m−2 year−1), and 0.06–0.30, respectively. A multiple-regression analysis suggested a positive effect of P availability on total NPP, whereas fine-root NPP was positively correlated with mean annual temperature and with P and negatively correlated with N. The biomass and longevity of fine roots increased in response to the impoverishment of soil P. The carbon (C) to P ratio (C/P) of fine roots was significantly and positively correlated with the P-use efficiency of above-ground litter production, indicating that tropical rainforest trees dilute P in fine roots to maintain the C allocation ratio to these roots. We highlighted the mechanisms regulating the fine-root productivity of tropical rainforest ecosystems in relation to the magnitude of nutrient deficiency. The trees showed C-conservation mechanisms rather than C investment as responses to decreasing soil P availability, which demonstrates that the below-ground systems at these sites are strongly limited by P, similar to the above-ground systems.
  • Masayuki Ushio, Shin Ichiro Aiba, Yayoi Takeuchi, Yoshiko Iida, Shunsuke Matsuoka, Rimi Repin, Kanehiro Kitayama
    Ecological Monographs 87 1 105 - 129 2017年02月01日 [査読有り][通常論文]
     
    © 2016 by the Ecological Society of America. We investigated consequences of plant-soil feedbacks (PSFs) in a tropical montane forest on Mt. Kinabalu in Borneo by measurements of light and soil conditions, ecophysiological analyses of tree seedlings, a long-term adult and seedling census, and a simple simulation model. The study plot (2.74 ha) is in a mixed conifer-broadleaf forest with 24% relative basal area of conifers. First, we investigated light and soil conditions beneath two dominant species, a conifer Dacrydium gracilis (Podocarpaceae, arbuscular mycorrhizal tree) and a broadleaf Lithocaprus clementianus (Fagaceae, ectomycorrhizal tree). The relative light intensity was marginally higher beneath Dacrydium tree crown than beneath Lithocarpus tree crown. The concentrations of inorganic nitrogen and labile phosphorus, and the nitrogen mineralization rate, were lower beneath Dacrydium than beneath Lithocarpus, suggesting that soils beneath Dacrydium were more nutrient deficient. Microscopic observations confirmed that conifer seedlings (including Dacrydium) harbored arbuscular mycorrhizal fungi. In addition, a molecular analysis showed that root-associated mycorrhizal fungal communities were clearly different between conifer and broadleaf seedlings, and consequently, nutrient acquisition capacity of seedlings may be different between them. Indeed, stable isotopic evidence suggested that Dacrydium seedlings are more efficient in inorganic nitrogen acquisition than Lithocarpus seedlings. These results predicted that the conifer seedlings would out-compete broadleaf seedlings and have a greater advantage beneath the conifer canopy. To test the possible advantage of conifer seedlings in performance, we developed hierarchical Bayesian models and estimated growth and mortality rates using the seedling census data during 2006-2012. We found that conifer seedlings performed better than broadleaf seedlings beneath Dacrydium canopy. On the other hand, broadleaf seedlings performed better than conifer seedlings beneath Lithocarpus canopy. The consequences of the PSFs for the tree community composition were investigated by developing a simple simulation model, and were compared with the results of a model without PSFs. After a 10 000-year simulation, the relative abundance of conifers with PSFs converged to 22%, which was consistent with the actual abundance; the model without effects of PSFs predicted a relative abundance of only ~10%. The results suggested that PSFs contributed to the maintenance of the conifer dominance in the tropical montane forest.
  • Martin J P Sullivan, Joey Talbot, Simon L Lewis, Oliver L Phillips, Lan Qie, Serge K Begne, Jerôme Chave, Aida Cuni-Sanchez, Wannes Hubau, Gabriela Lopez-Gonzalez, Lera Miles, Abel Monteagudo-Mendoza, Bonaventure Sonké, Terry Sunderland, Hans Ter Steege, Lee J T White, Kofi Affum-Baffoe, Shin-Ichiro Aiba, Everton Cristo de Almeida, Edmar Almeida de Oliveira, Patricia Alvarez-Loayza, Esteban Álvarez Dávila, Ana Andrade, Luiz E O C Aragão, Peter Ashton, Gerardo A Aymard C, Timothy R Baker, Michael Balinga, Lindsay F Banin, Christopher Baraloto, Jean-Francois Bastin, Nicholas Berry, Jan Bogaert, Damien Bonal, Frans Bongers, Roel Brienen, José Luís C Camargo, Carlos Cerón, Victor Chama Moscoso, Eric Chezeaux, Connie J Clark, Álvaro Cogollo Pacheco, James A Comiskey, Fernando Cornejo Valverde, Eurídice N Honorio Coronado, Greta Dargie, Stuart J Davies, Charles De Canniere, Marie Noel Djuikouo K, Jean-Louis Doucet, Terry L Erwin, Javier Silva Espejo, Corneille E N Ewango, Sophie Fauset, Ted R Feldpausch, Rafael Herrera, Martin Gilpin, Emanuel Gloor, Jefferson S Hall, David J Harris, Terese B Hart, Kuswata Kartawinata, Lip Khoon Kho, Kanehiro Kitayama, Susan G W Laurance, William F Laurance, Miguel E Leal, Thomas Lovejoy, Jon C Lovett, Faustin Mpanya Lukasu, Jean-Remy Makana, Yadvinder Malhi, Leandro Maracahipes, Beatriz S Marimon, Ben Hur Marimon Junior, Andrew R Marshall, Paulo S Morandi, John Tshibamba Mukendi, Jaques Mukinzi, Reuben Nilus, Percy Núñez Vargas, Nadir C Pallqui Camacho, Guido Pardo, Marielos Peña-Claros, Pascal Pétronelli, Georgia C Pickavance, Axel Dalberg Poulsen, John R Poulsen, Richard B Primack, Hari Priyadi, Carlos A Quesada, Jan Reitsma, Maxime Réjou-Méchain, Zorayda Restrepo, Ervan Rutishauser, Kamariah Abu Salim, Rafael P Salomão, Ismayadi Samsoedin, Douglas Sheil, Rodrigo Sierra, Marcos Silveira, J W Ferry Slik, Lisa Steel, Hermann Taedoumg, Sylvester Tan, John W Terborgh, Sean C Thomas, Marisol Toledo, Peter M Umunay, Luis Valenzuela Gamarra, Ima Célia Guimarães Vieira, Vincent A Vos, Ophelia Wang, Simon Willcock, Lise Zemagho
    Scientific reports 7 39102 - 39102 2017年01月17日 [査読有り][通常論文]
     
    Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity.
  • 澤田, 佳美, 相場, 慎一郎, 清野, 達之, 北山, 兼弘
    日本生態学会誌 67 3 323 - 330 一般社団法人 日本生態学会 2017年 [査読有り][通常論文]
     
    世界の熱帯における球果類の分布を見ると、撹乱跡地や貧栄養土壌を除くと山地に限定される。熱帯山地林で、球果類がどのようにして広葉樹と共存しているのかについては、未解明な点が残されている。広葉樹との共存に重要な要因の1つと考えられる球果類の更新について、定量的なデータがそろっているボルネオ・キナバル山の研究成果を中心に説明した。キナバル山に設置された調査区における球果類の優占度は、他の熱帯域における傾向と同様、山地林の、特に蛇紋岩地で高かった。球果類の更新について、そのサイズ構造から検討すると、山地林以上の非蛇紋岩地では撹乱に依存した更新と考えられる山型、蛇紋岩地では持続的な更新が行われていると考えられる逆J字型を示した。球果類と広葉樹の成長速度を比較すると、標高1700 m以上の非蛇紋岩地では、ギャップ下など光条件が良いところでのみ球果類の成長速度は広葉樹と同等以上となるのに対し、蛇紋岩地では光条件に
  • Mana Mukai, Shin ichiro Aiba, Kanehiro Kitayama
    Ecological Research 31 5 719 - 730 2016年09月01日 [査読有り][通常論文]
     
    © 2016, The Ecological Society of Japan. The vegetation on Yakushima Island, Japan, grows on soils derived from Akahoya volcanic ash, released from the Kikai Caldera about 7300 years ago. The eruption was devastating and it is believed that primary succession and soil formation reinitiated across all altitudes at this point. We hypothesize that the concentrations of soil total phosphorus (P) and labile P fractions increase with increasing altitude because the soil formation has progressed less in upslope areas as a result of the cooler temperature and because of the ample P source of the volcanic ash. Conversely, we hypothesize that the concentration of soil inorganic nitrogen (N) decreases with increasing altitude. Available soil P and N would result in increasing P limitation downslope and increasing N limitation upslope, respectively. We studied soil P fractions and soil inorganic N, and P- and N-use efficiencies of the seven forests on Yakushima along an elevation gradient (170–1550 m a.s.l.). Contrary to our hypotheses, soil total P, labile soil P fractions, and inorganic N decreased with increasing altitude. The P- and N-use efficiencies of the forests were negatively correlated with the concentration of soil total active P (total P minus occluded P) and inorganic N, respectively. We suggest that progressive soil acidity and slower decomposition under cooler and wetter environments upslope must have dissolved the P contained in volcanic ash and accelerated P leaching. Forest ecosystems on Yakushima that show a distinct altitudinal zonation are, therefore, characterized by increasing P and N shortage with increasing altitude.
  • Yoshimi Sawada, Shin Ichiro Aiba, Masaaki Takyu, Rimi Repin, Jamili Nais, Kanehiro Kitayama
    Journal of Tropical Ecology 31 2 117 - 128 2015年03月05日 [査読有り][通常論文]
     
    © 2015 Cambridge University Press. To understand the variation in community dynamics of tropical montane forests along gradients of soil fertility, death, recruitment and growth of trees (≥5 cm diameter) were monitored over 14 y (1997-2011) in nine plots placed in a matrix of three geological substrate types (Quaternary sediments, Tertiary sedimentary rocks and ultrabasic rocks) and three topographical units (ridge, middle and lower slopes) on Mount Kinabalu, Borneo. The plot area was 0.05 ha for ridge, 0.1 ha for middle slope and 0.2 ha (on ultrabasic rocks) and 1 ha (on the other substrates) for lower slope. Recruitment rates did not show a consistent pattern across geological substrates or topographies. Mortality rates were relatively high in almost all plots during the 1997-1999 period, including the El Ninõ drought, and in three plots on ultrabasic rocks during 2001-2005. Binomial logistic regression analyses showed that mortality during 1997-1999 increased with soil fertility (soluble phosphorus). Background mortality, excluding these periods, did not differ across geological substrates or topographies. The average growth rate during 1997-2011 was higher on more fertile soils and positively correlated with mortality during 1997-1999. We suggest that a high mortality rate during the drought period was related to high species diversity on more fertile soils, whereas a lower growth rate was related to stunted structures on poorer soils.
  • Hanya G, Aiba S
    Forestry Studies in China 23 2 231 - 122 2011年06月 [査読有り][通常論文]
     
    Hanya, G & Aiba, S, 2011, 'Annual periodicity of fruiting in temperate forests in Yakushima, Japan', <i>Forestry Studies in China</i>, vol. 23, no. 2, pp. 231-122.
  • Hanya G, Aiba S
    Ecological Research 38 6 342 - 1090 2010年11月 [査読有り][通常論文]
     
    Hanya, G & Aiba, S, 2010, 'Fruit fall in tropical and temperate forests: implications for frugivore diversity', <i>Ecological Research</i>, vol. 38, no. 6, pp. 342-1090.
  • Hanya G, Aiba S
    Forestry Studies in China 14 4 189 - 192 2010年09月 [査読有り][通常論文]
     
    Hanya, G & Aiba, S, 2010, 'Fruit fall in five warm- and cool-temperate forests in Yakushima, Japan', <i>Forestry Studies in China</i>, vol. 14, no. 4, pp. 189-192.
  • 武生 雅明, 久保田 康裕, 相場 慎一郎, 清野 達之, 西村 貴司
    種生物学研究 29 247 - 265 文一総合出版 2006年03月31日 [査読無し][通常論文]
  • AIBA S, SUZUKI E, KITAYAMA K
    Tropics 6 1/2 1 - 236 2006年 [査読有り][通常論文]
     
    AIBA, S, SUZUKI, E & KITAYAMA, K, 2006, 'Structural and floristic variation among small replicate plots of a tropical montane forest on Mount Kinabalu, Sabah, Malaysia', <i>Tropics</i>, vol. 6, no. 1/2, pp. 1-236.
  • Aiba S, Takyu M, Kitayama K
    Ecological Research 22 3 69 - 286 2005年05月 [査読有り][通常論文]
     
    Aiba, S, Takyu, M & Kitayama, K, 2005, 'Dynamics, productivity and species richness of tropical rainforests along elevational and edaphic gradients on Mount Kinabalu, Borneo', <i>Ecological Research</i>, vol. 22, no. 3, pp. 69-286.
  • Kitayama K, Suzuki S, Hori M, Takyu M, Aiba S, Majalap-Lee N, Kikuzawa K
    Oecologia 140 2. 2004年07月 [査読有り][通常論文]
     
    Kitayama, K, Suzuki, S, Hori, M, Takyu, M, Aiba, S, Majalap-Lee, N & Kikuzawa, K, 2004, 'On the relationships between leaf-litter lignin and net primary productivity in tropical rain forests', <i>Oecologia</i>, vol. 140, no. 2.
  • K Kitayama, SI Aiba, M Takyu, N Majalap, R Wagai
    ECOSYSTEMS 7 3 259 - 274 2004年04月 [査読有り][通常論文]
     
    We compared phosphorus (P) dynamics and plant productivity in two montane tropical rain forests (Mount Kinabalu, Borneo) that derived from similar parent materials (largely sedimentary rocks) and had similar climates but differed in terms of soil age. The younger site originated from Quaternary colluvial deposits, whereas the older site had Tertiary-age material. The older site had a distinctive spodic horizon, reduced levels of labile inorganic soil P, higher concentrations of recalcitrant organic soil P, and lower rates of net soil N mineralization. P fertilization led to soil nitrogen (N) immobilization in the P-deficient soil, indicating that soil N mineralization was limited by P at the P-deficient older site. Mean foliar nutrient concentration (on both a weight and an area basis) was similar at the two sites for all elements except P, which was lower at the older site. Aboveground net primary production (ANPP) was lower at the older site than at the younger one; this difference could be explained by the reduced availability of P and N (as down-regulated by P) at the older site. The relatively ample allocation of P and N to leaves, despite the reduced availability at the P-deficient old site, was attributable to its high resorption efficiency. High resorption resulted in lower concentrations of elements in leaf litter-that is, less decomposable low-quality litter. On the other hand, the concentration of leaf litter lignin was considerably lower at the older site; this appeared to be a de facto adaptive mechanism to avoid retarding litter decomposition.
  • Aiba S, Kitayama K
    Journal of Tropical Ecology 18 02. 2002年03月 [査読有り][通常論文]
     
    Aiba, S & Kitayama, K, 2002, 'Effects of the 1997–98 El Niño drought on rain forests of Mount Kinabalu, Borneo', <i>Journal of Tropical Ecology</i>, vol. 18, no. 02.
  • 北山兼弘, 相場慎一郎, 武生雅明
    日本生態学会誌,Vol.52,125-129 2002年 [査読有り][通常論文]
  • Species composition and species-area relationships of trees in nine permanent plots in altitudinal sequences on different geological substrates of Mount Kinabalu.
    Aiba S, Kitayama K, Repin R
    Sabah Parks Nature Journal,Vol.5,7-70 2002年 [査読有り][通常論文]
  • Control of organic carbon density in vegetation and soils of tropical rain forest ecosystems on Mount Kinabalu.
    Kitayama K, Aiba S
    Sabah Parks Nature Journal,Vol.5,71-90 2002年 [査読有り][通常論文]
  • Beta diversity and forest structural changes along topographical gradients on different geological substrates in tropical montane forests on Mt. Kinabalu.
    Takyu M, Aiba S, Kitayama K
    Sabah Parks Nature Journal,Vol.5,165-218 2002年 [査読有り][通常論文]
  • Aiba S, Hill D, Agetsuma N
    Forest Ecology and Management 9 2-3 295 - 175 2001年01月 [査読有り][通常論文]
     
    Aiba, S, Hill, D & Agetsuma, N, 2001, 'Comparison between old-growth stands and secondary stands regenerating after clear-felling in warm-temperate forests of Yakushima, southern Japan', <i>Forest Ecology and Management</i>, vol. 9, no. 2-3, pp. 295-175.
  • Aiba S, Kohyama T
    The Journal of Ecology 85 5 1997年10月 [査読有り][通常論文]
     
    Aiba, S & Kohyama, T, 1997, 'Crown Architecture and Life-History Traits of 14 Tree Species in a Warm- Temperate Rain Forest: Significance of Spatial Heterogeneity', <i>The Journal of Ecology</i>, vol. 85, no. 5, p. 611.
  • Bellingham P, Kohyama T, Aiba S
    Ecological Research 82 3 911 - 247 1996年12月 [査読有り][通常論文]
     
    Bellingham, P, Kohyama, T & Aiba, S, 1996, 'The effects of a typhoon on Japanese warm temperate rainforests', <i>Ecological Research</i>, vol. 82, no. 3, pp. 911-247.
  • Aiba S, Kohyama T
    The Journal of Ecology 84 2 1996年04月 [査読有り][通常論文]
     
    Aiba, S & Kohyama, T, 1996, 'Tree Species Stratification in Relation to Allometry and Demography in a Warm-Temperate Rain Forest', <i>The Journal of Ecology</i>, vol. 84, no. 2, p. 207.
  • KOHYAMA T, AIBA S
    Tropics 109 1093 53 - 392 1996年 [査読有り][通常論文]
     
    KOHYAMA, T & AIBA, S, 1996, 'Dynamics of Primary and Secondary Warm-temperate Rain Forests in Yakushima Island', <i>Tropics</i>, vol. 109, no. 1093, pp. 53-392.

書籍

  • 日本生態学会, 正木, 隆, 相場, 慎一郎 
    共立出版 2011年10月 (ISBN: 9784320057364) xviii, 293p, 図版 [4] p
  • 続く:生命誌年刊号vol.57-60(分担執筆pp. 96-117「熱帯林樹木の多様性が続くしくみ」)
    新曜社 2009年
  • メタ群集と空間スケール(分担執筆pp.1-26「熱帯林樹木の種多様性:異なる空間スケールで見る」)
    京都大学学術出版会 2008年
  • 世界遺産屋久島(分担執筆pp. 96-101「春田浜の植生」)
    朝倉書店 2006年
  • 世界遺産屋久島(分担執筆pp. 102-117「屋久島の森林の構造と機能」).
    朝倉書店 2006年
  • 森の自然史(分担執筆pp.134-145「照葉樹林の構造と樹木群集の構成」)
    北海道大学図書刊行会 2000年

その他活動・業績

  • 向井真那, 相場慎一郎, 北山兼弘 日本森林学会大会学術講演集 130th 149 2019年03月20日 [査読無し][通常論文]
  • 向井真那, 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨(Web) 64th ROMBUNNO.D02‐07 (WEB ONLY) 2017年 [査読無し][通常論文]
  • Yoshimi Sawada, Shin ichiro Aiba, Tatsuyuki Seino, Kanehiro Kitayama Plant and Soil 403 (1-2) 103 -114 2016年06月01日 [査読有り][通常論文]
     
    © 2015 Springer International Publishing Switzerland Background and Aim: Conifers often co-occur with angiosperm trees at high altitudes and on infertile soils in tropical rainforests. To explore the mechanism of conifer–angiosperm coexistence, we investigated size structure, growth rate and regeneration of conifers along soil gradient across altitudes and geological substrates. Methods: Tree measurements were conducted in ten plots (0.06–1 ha) with varied geology at four altitudes (700, 1700, 2700 and 3100 m) on Mount Kinabalu, Borneo. Conifer juveniles were counted and understory light conditions were analyzed with hemispherical photographs. Results: Size structure of conifers showed inverse-J shape distributions on ultrabasic rocks at ≥1700 m but unimodal or sporadic distributions in other plots. Densities of conifer seedlings and saplings were generally greater on ultrabasic rocks than on non-ultrabasic substrates at comparable altitudes, which concurred with the pattern in understory light conditions. Growth rates over 4 (or 5) years of conifers at 4.8–25 cm diameter were higher than angiosperm trees only under well-lit conditions on non-ultrabasic substrates, but were always similar or higher on ultrabasic rocks even in shaded conditions. Conclusions: Conifers showed continuous regeneration on ultrabasic rocks at ≥1700 m. This suggested that, on infertile soils, competition with angiosperm trees was relaxed and well-lit understory facilitated recruitment of conifers.
  • Kazuki Miyamoto, Rota Wagai, Shin ichiro Aiba, Reuben Nilus Trees - Structure and Function 30 (2) 385 -394 2016年04月 [査読有り][通常論文]
     
    © 2015 Springer-Verlag Berlin Heidelberg Key message: Borneo’s tropical heath (kerangas) forest has limited soil nutrient availability, and high variation in aboveground structure and fine-root biomass. This variation depends on altitude and soil nitrogen availability.Abstract: To elucidate the biotic and abiotic factors affecting the variation in fine-root biomass (FRB, <2 mm diameter) of trees growing under nutrient-poor environments in Sabah, North Borneo, we investigated FRB in different forests with varying soil nitrogen (N) availability. We selected two study sites at different altitudes: the Maliau Basin (ca. 1000 m asl) and Nabawan (ca. 500 m asl). Both sites included tropical heath (kerangas) forest, on infertile soils (podzols) with a surface organic horizon overlying a bleached (eluviated) mineral horizon, and taller forests on more fertile non-podzolic soils. FRB was obtained from each plot by soil coring (to a depth of 15 cm). FRB increased with decreasing soil inorganic N content (NH<inf>4</inf>–N and NO<inf>3</inf>–N), tree height, and aboveground biomass. Thus, higher proportions of carbon resources were allocated to fine-roots in stands with lower N availability. FRB was significantly greater at the Maliau Basin than at Nabawan, reflecting lower soil N availability at higher altitude. Our results demonstrate high variation in FRB among the heath forests, and suggest that fine-root development is more prominent under a cooler climate where N availability limits tree growth owing to slower decomposition. The variation in N availability under the same climate (i.e., at the same altitude) appears to be related to the extent of soil podzolization.
  • 向井真那, 相場慎一郎, 北山兼弘 日本土壌肥料学会講演要旨集 61 93 2015年09月09日 [査読無し][通常論文]
  • J. W Ferry Slik, Víctor Arroyo-Rodríguez, Shin Ichiro Aiba, Patricia Alvarez-Loayza, Luciana F. Alves, Peter Ashton, Patricia Balvanera, Meredith L. Bastian, Peter J. Bellingham, Eduardo Van, Den Berg, Luis Bernacci, Polyanna, Da Conceição Bispo, Lilian Blanc, Katrin Böhning-Gaese, Pascal Boeckx, Frans Bongers, Brad Boyle, Matt Bradford, Francis Q. Brearley, Mireille Breuer, Ndoundou Hockemba, Sarayudh Bunyavejchewin, Darley Calderado Leal Matos, Miguel Castillo-Santiago, Eduardo L, M Catharino, Shauna Lee Chai, Yukai Chen, Robert K. Colwell, Robin L. Chazdon, Connie Clark, David B. Clark, Deborah A. Clark, Heike Culmsee, Kipiro Damas, Handanakere S. Dattaraja, Gilles Dauby, Priya Davidar, Saara J. DeWalt, Jean Louis Doucet, Alvaro Duque, Giselda Durigan, Karl A O Eichhorn, Pedro V. Eisenlohr, Eduardo Eler, Corneille Ewango, Nina Farwig, Kenneth J. Feeley, Leandro Ferreira, Richard Field, Ary T. De, Oliveira Filho, Christine Fletcher, Olle Forshed, Geraldo Franco, Gabriella Fredriksson, Thomas Gillespie, Jean François Gillet, Giriraj Amarnath, Daniel M. Griffith, James Grogan, Nimal Gunatilleke, David Harris, Rhett Harrison, Andy Hector, Jürgen Homeier, Nobuo Imai, Akira Itoh, Patrick A. Jansen, Carlos A. Joly, Bernardus H, J, De Jong, Kuswata Kartawinata, Elizabeth Kearsley, Daniel L. Kelly, David Kenfack, Michael Kessler, Kanehiro Kitayama, Robert Kooyman, Eileen Larney, Yves Laumonier, Susan Laurance, William F. Laurance, Michael J. Lawes, Ieda Leao Do Amaral, Susan G. Letcher, Jeremy Lindsell, Xinghui Lu, Asyraf Mansor, Antti Marjokorpi, Emanuel H. Martin, Henrik Meilby, Felipe P L Melo, Daniel J. Metcalfe, Vincent P. Medjibe, Jean Paul Metzger, Jerome Millet, D. Mohandass, Juan C. Montero, Márcio De, Morisson Valeriano, Badru Mugerwa, Hidetoshi Nagamasu, Reuben Nilus, Susana Ochoa-Gaona Proceedings of the National Academy of Sciences of the United States of America 112 2015年08月18日 [査読無し][通常論文]
  • J. W Ferry Slik, Víctor Arroyo-Rodríguez, Shin Ichiro Aiba, Patricia Alvarez-Loayza, Luciana F. Alves, Peter Ashton, Patricia Balvanera, Meredith L. Bastian, Peter J. Bellingham, Eduardo Van, Den Berg, Luis Bernacci, Polyanna, Da Conceição Bispo, Lilian Blanc, Katrin Böhning-Gaese, Katrin Böhning-Gaese, Pascal Boeckx, Frans Bongers, Brad Boyle, Matt Bradford, Francis Q. Brearley, Mireille Breuer, Ndoundou Hockemba, Sarayudh Bunyavejchewin, Darley Calderado Leal Matos, Miguel Castillo-Santiago, Eduardo L, M Catharino, Shauna Lee Chai, Yukai Chen, Robert K. Colwell, Robert K. Colwell, Chazdon L. Robin, Connie Clark, David B. Clark, Deborah A. Clark, Heike Culmsee, Kipiro Damas, Handanakere S. Dattaraja, Gilles Dauby, Priya Davidar, Saara J. DeWalt, Jean Louis Doucet, Alvaro Duque, Giselda Durigan, Karl A O Eichhorn, Pedro V. Eisenlohr, Eduardo Eler, Corneille Ewango, Nina Farwig, Kenneth J. Feeley, Leandro Ferreira, Richard Field, Ary T. De, Oliveira Filho, Christine Fletcher, Olle Forshed, Geraldo Franco, Gabriella Fredriksson, Thomas Gillespie, Jean François Gillet, Giriraj Amarnath, Daniel M. Griffith, James Grogan, Nimal Gunatilleke, David Harris, Rhett Harrison, Rhett Harrison, Andy Hector, Jürgen Homeier, Nobuo Imai, Akira Itoh, Patrick A. Jansen, Patrick A. Jansen, Carlos A. Joly, Bernardus H, J, De Jong, Kuswata Kartawinata, Elizabeth Kearsley, Daniel L. Kelly, David Kenfack, Michael Kessler, Kanehiro Kitayama, Robert Kooyman, Eileen Larney, Yves Laumonier, Susan Laurance, William F. Laurance, Michael J. Lawes, Ieda Leao Do Amaral, Susan G. Letche, Jeremy Lindsell, Xinghui Lu, Asyraf Mansor, Antti Marjokorpi, Emanuel H. Martin, Emanuel H. Martin, Henrik Meilby, Felipe P L Melo, Daniel J. Metcalfe, Vincent P. Medjibe, Jean Paul Metzger, Jerome Millet, D. Mohandass, Juan C. Montero Proceedings of the National Academy of Sciences of the United States of America 112 (24) 7472 -7 2015年06月16日 [査読有り][通常論文]
     
    © 2015, National Academy of Sciences. All rights reserved. The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼40,000 and ∼53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.
  • Kanehiro Kitayama, Yuki Tsujii, Ryota Aoyagi, Shin ichiro Aiba Journal of Ecology 103 (3) 606 -615 2015年05月01日 [査読有り][通常論文]
     
    © 2015 The Authors. Journal of Ecology © 2015 British Ecological Society. Tropical rain forests in SE Asia are well known for the occurrence of supra-annual synchronous reproductive events, masting. Answering the question how trees allocate carbon (C), nitrogen (N) and phosphorus (P) to such irregular but gregarious reproduction requires a long-term observation. We conducted a 10-year continuous monitoring of litterfall in eight tropical rain forests, which differ significantly in P (and N) availability on Mount Kinabalu, Borneo. Mean P concentration in reproductive organ litter decreased significantly with increasing P-use efficiency of net primary production (PUE), an index of P deficiency. Therefore, P in reproductive organ litter became diluted as the magnitude of P deficiency increased. Mean annual litterfall (kg ha<sup>-1</sup> yr<sup>-1</sup>) of reproductive organs over the 10 years ranged from 128.5 to 730.9 across the eight forests. Long-term C allocation ratio to reproductive organs (i.e. C in reproductive organs per C in total litterfall) varied from 2.0% to 7.8% across the eight forests and did not relate with PUE, indicating that long-term C allocation ratio to reproduction was not controlled by the availability of the most critical soil nutrient. Long-term N allocation ratio to reproduction varied from 2.7% to 9.9% and significantly positively related with C allocation ratio. The quotient of N allocation ratio to C allocation ratio ranged from 1.1 to 1.4. Long-term P allocation ratio to reproduction varied from 9.8% to 16.4%. The quotient of P allocation ratio to C allocation ratio ranged from 1.6 to 5.0. Therefore, tropical trees allocated much greater proportion of P to reproduction than C and N over the 10 years. Moreover, trees disproportionately increased P allocation to reproduction with decreasing C allocation to reproduction. Trees adjusted P allocation relative to C allocation and maintained a narrow range of P allocation ratio to reproduction in the long run in each site. Synthesis. Reproduction in Bornean tropical rain forests costs more P than C and N. Our results suggest that reproductive events in these forests are regulated by P at the level of overall long-term mean. Understanding patterns and processes of reproductive events requires a long-term monitoring of nutrient dynamics.
  • 澤田佳美, 相場慎一郎, 清野達之, 北山兼弘 日本生態学会大会講演要旨(Web) 62nd PA2-015 (WEB ONLY) 2015年 [査読無し][通常論文]
  • 向井真那, 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨(Web) 62nd PA1-197 (WEB ONLY) 2015年 [査読無し][通常論文]
  • Shin Ichiro Aiba, Yoshimi Sawada, Masaaki Takyu, Tatsuyuki Seino, Kanehiro Kitayama, Rimi Repin Australian Journal of Botany 63 (3-4) 191 -203 2015年 [査読有り][通常論文]
     
    © CSIRO 2015. We describe here the structure, floristics and diversity of tropical montane rain forests over ultramafic soils on Mount Kinabalu, Borneo, and compared them with those on non-ultramafic soils. We used 14 sample plots from 1580 to 3080m elevation, six on ultramafic soils and eight on non-ultramafic soils, and identified all trees ≥4.8 cm diameter. The plot area ranged from 0.1 to 1ha, the majority (nine plots) being 0.25ha. Forests on ultramafic soils showed more stunted structure, especially at higher altitudes, than those on non-ultramafic soils and on ridges than on slopes. Species of Coniferae (Araucariaceae and Podocarpaceae) and Myrtaceae strongly dominated on ultramafic soils occupying 61-96% of basal area in each plot, compared with 22-63% on non-ultramafic soils. Among 287 species found in the 14 plots, only nine species (including four species endemic to Mount Kinabalu) were strictly restricted to ultramafic soils. Nonmetric multidimensional scaling demonstrated that elevational change in species composition was accelerated on ultramafic soils and on ridges. Tree species diversity was generally lower on ultramafic soils than on non-ultramafic soils at the comparative altitudes. Multiple regression analysis suggested that soil nutrients (phosphorus and nitrogen) could be the cause of vegetation differentiation between ultramafic and non-ultramafic soils, although the data on soil metals are lacking. Comparison of our results with those from other mountains with ultramafic soils in South-east Asia demonstrated the uniqueness of the montane rain forests over ultramafic soils on Mount Kinabalu.
  • Goro Hanya, Mieko Fuse, Shin Ichiro Aiba, Hino Takafumi, Riyou Tsujino, Naoki Agetsuma, Colin A. Chapman, Colin A. Chapman American Journal of Primatology 76 (6) 596 -607 2014年06月 [査読有り][通常論文]
     
    Comparing animal consumption to plant primary production provides a means of assessing an animal's impact on the ecosystem and an evaluation of resource limitation. Here, we compared annual fruit and leaf consumption by Japanese macaques (Macaca fuscata) relative to the annual production of these foods in the lowlands and highlands of Yakushima Island, Japan. We estimated consumption by macaques by the direct observation of macaque groups for 1 year in each habitat. We estimated leaf production as the sum of leaf litter fall (corrected for the effect of translocated organic and inorganic matter) and folivory by insects (assumed to be 10%) and by macaques. We estimated fruit production as the sum of fruit litter fall and consumption by birds (estimated by the seed fall) and macaques. The impact of macaque folivory at the community level was negligible relative to production (∼0.04%) compared with folivory by insects (assumed to be 10%); however, for some species, macaque folivory reached up to 10.1% of production. Tree species on which macaques fed did not decline in abundance over 13 years, suggesting that their folivory did not influence tree species dynamics. For the three major fleshy-fruited species in the highland site, macaques consumed a considerable portion of total fruit production (6-40%), rivaling the consumption by birds (32-75%). We conclude that at the community level, macaque folivory was negligible compared with the leaf production, but frugivory was not. Am. © 2013 Wiley Periodicals, Inc.
  • 向井真那, 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨(Web) 61st PC2-017 (WEB ONLY) 2014年 [査読無し][通常論文]
  • 澤田佳美, 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨(Web) 61st PA1-010 (WEB ONLY) 2014年 [査読無し][通常論文]
  • Yusuke Onoda, Yusuke Onoda, Jema B. Saluñga, Kosuke Akutsu, Shin ichiro Aiba, Tetsukazu Yahara, Niels P R Anten Journal of Ecology 102 (1) 167 -175 2014年01月 [査読有り][通常論文]
     
    Taller plant species can pre-empt solar energy and suppress growth of subordinate species in vegetation stands, which is described through one-sided competition. Yet, in much of the world's vegetation species of different statures coexist. This study aims to clarify the mechanisms underlying this apparent paradox. We quantified how co-occurring species and individuals intercepted and used light for growth in a mature, warm-temperate evergreen forest. This was performed by determining the 3D distribution of foliage and light with a ground-based lidar system in combination with nondestructive measurements of plant growth. Taller trees intercepted light more efficiently per unit of above-ground biomass than shorter trees did (=higher light interception efficiency, LIE). However, taller trees tended to have lower biomass production per unit light interception (=lower light use efficiency, LUE). Reduced LUE in taller trees was associated with their higher biomass allocation to nonphotosynthetic organs and probably with over-saturated light intensity for photosynthesis at high canopy positions. Due to the increased LIE and decreased LUE with tree heights, a trade-off between LIE and LUE was found, and this trade-off resulted in trees of different statures having similar relative growth rates. Synthesis. Light competition drives trees to grow taller, and the light interception efficiency is higher in taller trees; however, this benefit comes at a cost of decreased efficiency of light use for growth. This trade-off allows trees of different statures to grow at proportionally comparable rates and may promote coexistence of tree species in one-sided light competition. Taller plants can pre-empt light and suppress growth of subordinate plants, yet in many vegetation species of different statures coexist. We explored the mechanisms underlying this apparent paradox using a novel combined analysis of tree growth and light interception. Taller trees were more efficient in light interception but less efficient in light utilization than shorter trees, resulting into similar relative growth rates across different tree heights. This mechanism may help to explain species coexistence under one-sided light competition. © 2013 British Ecological Society.
  • Shin Ichiro Aiba, Kosuke Akutsu, Yusuke Onoda Annals of Botany 112 (9) 1899 -1909 2013年12月 [査読有り][通常論文]
     
    Background and Aims Globally, conifer dominance is restricted to nutient-poor habitats in colder, drier or waterlogged environments, probably due to competition with angiosperms. Analysis of canopy structure is important for understanding the mechanism of plant coexistence in relation to competition for light. Most conifers are shade intolerant, and often have narrow, deep, conical crowns. In this study it is predicted that conifer-admixed forests have less distinct upper canopies and more undulating canopy surfaces than angiosperm-dominated forests. Methods By using a ground-based, portable light detection and ranging (LIDAR) system, canopy structure was quantified for old-growth evergreen rainforests with varying dominance of conifers along altitudinal gradients (200-3100 m a.s.l.) on tropical and sub-tropical mountains (Mount Kinabalu, Malaysian Borneo and Yakushima Island, Japan) that have different conifer floras. Key Results Conifers dominated at higher elevations on both mountains (Podocarpaceae and Araucariaceae on Kinabalu and Cupressaceae and Pinaceae onYakushima), but conifer dominance also varied with soil/substrate conditions on Kinabalu. Conifer dominance was associated with the existence of large-diameter conifers. Forests with higher conifer dominance showed a canopy height profile (CHP) more skewed towards the understorey on both Kinabalu and Yakushima. In contrast, angiosperm-dominated forests had a CHP skewed towards upper canopy, except for lowland dipterocarp forests and a sub-alpine scrub dominated by small-leaved Leptospermum recurvum (Myrtaceae) on Kinabalu. Forests with a less dense upper canopy had more undulating outer canopy surfaces. Mixed conifer-angiosperm forests on Yakushima and dipterocarp forests on Kinabalu showed similar canopy structures. Conclusions The results generally supported the prediction, suggesting that lower growth of angiosperm trees (except L. recurvum on Kinabalu) in cold and nutrient-poor environments results in a sparser upper canopy, which allows shade-intolerant conifers to co-occur with angiosperm trees either as emergents or as codominants in the open canopy. © The Author 2013.
  • Shizuo Suzuki, Shizuo Suzuki, Kanehiro Kitayama, Shin ichiro Aiba, Masaaki Takyu, Kihachiro Kikuzawa, Kihachiro Kikuzawa Journal of Forest Research 18 (4) 353 -360 2013年08月 [査読有り][通常論文]
     
    Few studies have been done on the quantification of stand-level leaf herbivory in tropical forests. We evaluated the significance of annual leaf loss due to folivorous insects on the calculation of aboveground net primary production (ANPP) in tropical rain forests along broad climatic and edaphic gradients on Mt. Kinabalu, Borneo. We estimated insect folivory at the stand level as the product of a lifetime leaf loss ratio and annual leaf production in the stand. We defined the lifetime leaf loss ratio as the ratio of litter-leaf mass consumed by folivorous insects to the total litter-leaf mass at the stand level. The lifetime leaf loss ratio ranged from 1.6 to 8.4 %. The annual leaf loss caused by folivorous insects ranged from 0.01 to 0.38 Mg C ha-1 year-1, or from 1.2 to 5.9 % of ANPP in these tropical rain forests. Our method of estimating folivory (1) simultaneously considers all the tree species, canopy layers, and species of folivorous insects, (2) avoids underestimating leaf herbivory due to the resorption of mobile organic and inorganic matter from senescent leaves at the time of leaf abscission, and (3) can readily be applied in forests elsewhere. © 2012 The Japanese Forest Society and Springer.
  • 澤田佳美, 相場慎一郎, 武生雅明, 北山兼弘 日本生態学会大会講演要旨集 60th 245 2013年03月05日 [査読無し][通常論文]
  • Nobuo Imai, Tatsuyuki Seino, Shin ichiro Aiba, Masaaki Takyu, Jupiri Titin, Kanehiro Kitayama Plant Ecology 213 (9) 1413 -1424 2012年09月 [査読有り][通常論文]
     
    Reduced-impact logging (RIL) is known to be beneficial in biodiversity conservation, but its effects on tree diversity remain unknown. Pattern of tree diversity following disturbance usually varies with spatial scale of sampling (i. e., plot size). We examined the impacts of RIL on species richness and community composition of tree species at different spatial scales, and the scale (plot size) dependency of the two metrics; species richness versus community similarity. One 2-ha and three to four 0. 2-ha plots were established in each of primary, RIL, and conventionally logged (CL) forest in Sabah, Malaysia. Species richness (the number of species per unit number of stems) was higher in the RIL than in the CL forest at both scales. The relationship between species richness and logging intensity varied with plot size. Species richness was greater in the RIL than in the primary forest at the 2-ha scale, while it was similar between the two forests at 0. 2-ha scale. Similarly, species richness in the CL forest demonstrated a greater value at the 2-ha scale than at the 0. 2-ha scale. Greater species richness in the two logged forests at the 2-ha scale is attributable to a greater probability of encountering the species-rich, small patches that are distributed heterogeneously. Community composition of the RIL forest more resembled that of the primary forest than that of the CL forest, regardless of plot size. Accordingly, species richness is a scale-dependent metric, while community similarity is a more robust metric to indicate the response of tree assemblage to anthropogenic disturbance. © 2012 Springer Science+Business Media B.V.
  • Goro Hanya, Pablo Stevenson, Maria van Noordwijk, Siew Te Wong, Tomoko Kanamori, Noko Kuze, Shin Ichiro Aiba, Colin A. Chapman, Carel van Schaik Ecography 34 (6) 1009 -1017 2011年12月 [査読有り][通常論文]
     
    We examine the effect of total annual food abundance and seasonal availability on the biomass and species richness for frugivorous primates on three continents (n=16 sites) by data on fruit fall. We reveal that the best-fit models for predicting primate biomass include total annual fruit fall (positive), seasonality (negative) and biogeography (Old World>New World and mainland>island) and that these factors explain 56-67% of the variation. For the number of species, the best-fit models include seasonality (negative) and biogeography (Old World>New World and mainland>island) but not total annual fruit fall. Annual temperature has additional effects on primate biomass when the effects of fruits and biogeography are controlled, but there is no such effect on species richness. The present results indicate that, measured on local scales, primate biomass and number of species is affected by the seasonal variation in food availability. © 2011 The Authors.
  • J. W Ferry Slik, Shin Ichiro Aiba, Meredith Bastian, Meredith Bastian, Francis Q. Brearley, Charles H. Cannon, Charles H. Cannon, Karl A O Eichhorn, Gabriella Fredriksson, Kuswata Kartawinata, Yves Laumonier, Asyraf Mansor, Antti Marjokorpi, Erik Meijaard, Robert J. Morley, Robert J. Morley, Robert J. Morley, Hidetoshi Nagamasu, Reuben Nilus, Eddy Nurtjahya, John Payne, Andrea Permana, Axel D. Poulsen, Niels Raes, Soedarsono Riswan, Carel P. Van Schaik, Douglas Sheil, Kade Sidiyasa, Eizi Suzuki, Johan L C, H Van Valkenburg, Campbell O. Webb, Serge Wich, Serge Wich, Tsuyoshi Yoneda, Rahmad Zakaria, Nicole Zweifel Proceedings of the National Academy of Sciences of the United States of America 108 (30) 12343 -12347 2011年07月26日 [査読有り][通常論文]
     
    The marked biogeographic difference between western (Malay Peninsula and Sumatra) and eastern (Borneo) Sundaland is surprising given the long time that these areas have formed a single landmass. A dispersal barrier in the form of a dry savanna corridor during glacial maxima has been proposed to explain this disparity. However, the short duration of these dry savanna conditions make it an unlikely sole cause for the biogeographic pattern. An additional explanation might be related to the coarse sandy soils of central Sundaland. To test these two nonexclusive hypotheses, we performed a floristic cluster analysis based on 111 tree inventories from Peninsular Malaysia, Sumatra, and Borneo. We then identified the indicator genera for clusters that crossed the central Sundaland biogeographic boundary and those that did not cross and tested whether drought and coarse-soil tolerance of the indicator genera differed between them.We found 11 terminal floristic clusters, 10 occurring in Borneo, 5 in Sumatra, and 3 in Peninsular Malaysia. Indicator taxa of clusters that occurred across Sundaland had significantly higher coarse-soil tolerance than did those from clusters that occurred east or west of central Sundaland. For drought tolerance, no such pattern was detected. These results strongly suggest that exposed sandy sea-bed soils acted as a dispersal barrier in central Sundaland. However, we could not confirm the presence of a savanna corridor. This finding makes it clear that proposed biogeographic explanations for plant and animal distributions within Sundaland, including possible migration routes for early humans, need to be reevaluated.
  • Toshihiro Yamada, Shin Ichiro Aiba, Yasuhiro Kubota, Kumiko Okubo, Itsuo Miyata, Eizi Suzuki, Hisayuki Maenaka, Masahiro Nagano Ecosphere 2 (7) 2011年07月01日 [査読有り][通常論文]
     
    Copyright © 2011 Yamada et al. To examine the dynamics of species diversity during secondary succession, growth, death and recruitment of trees were monitored for 39 years (1966 to 2005) in two plots (P-1 and P-3, 40 m×40 m each) in a Japanese warm-temperate secondary forest recovering from clearcutting that occurred in the 1910s. Typhoons in the early 1990s seriously damaged P-1 and moderately damaged P-3. We examined how species diversity of trees changed through succession for three size classes: large (diameter at breast height, dbh ≥ 4.5 cm), medium (4.5 cm > dbh ≥ 1.0 cm), and small (dbh < 1.0 cm). Before the typhoons occurred, species diversity and evenness generally increased over time in all size classes in both plots, except for medium trees in P-1. After the typhoons, species diversity increased over time without exception, and this usually involved increases in both species evenness and number. We found that recruitment always contributed to increases in species diversity but mortality did not. Recruitment increased species diversity because the recruitment rate of rare species was higher than that of abundant species. This reflected delayed recruitment of late successional species before the typhoons and the mass recruitment of early successional species after the typhoons. Abundance of the most dominant tree species of the large class in P-1 was greatly reduced due to mortality caused by the typhoon, resulting in an increase in species diversity in the large tree community. Gap formation by the typhoons also caused mass recruitment into the small and medium size classes, including many rare species, leading to increased species diversity in the small and medium tree communities. Through these processes, the typhoons enhanced species diversity in this Japanese warm-temperate forest. Synthesis: This is the first study on the dynamics of species diversity based on long-term monitoring of a single site in a Japanese warm-temperate forest. This direct monitoring revealed the species dynamics plus the significant impact of rare events, typhoons, on the species diversity.
  • Goro Hanya, Shin ichiro Aiba Forestry Studies in China 13 (2) 112 -122 2011年06月 [査読有り][通常論文]
     
    Fruiting phenology, assessed by seed fall, in five warm- and cool-temperate forests on Yakushima Island, southern Japan, was studied for two years in one 50m × 50m plot and for four years in four 100m ×50m plots. The elevation of the plots ranged between 170 and 1200m a.s.l Seed fall phenology showed annual periodicity in all five plots. This was clear when assessed by the number of species but became less clear when assessed by the biomass of seed litter. Community-level annual periodicity was based on the prevalence of population-level annual periodicity and interspecific synchronization of the fruiting peak from autumn to winter. Fleshy fruits had peaks of seed fall in a wider range of months than non-fleshy fruits, since it is sometimes beneficial to bear fruit outside the community-level fruiting peaks in order to avoid interspecific competition for animal seed dispersers. No consistent effect of climatic factors on seed fall phenology was detected. © Beijing Forestry University and Springer Berlin Heidelberg.2011.
  • S. Aiba, M. Takyu, K. Kitayama Tropical Montane Cloud Forests: Science for Conservation and Management 579 -583 2011年01月01日 [査読有り][通常論文]
     
    © Cambridge University Press 2010. Biennial variation in tree diameter growth was studied during eight years (1995–2003) in nine tropical rain forests on Mt. Kinabalu, Sabah, Malaysian Borneo. These forests are located at four altitudes (700, 1700, 2700, and 3100 m.a.s.l.) on contrasting geological substrates (ultrabasic versus non-ultrabasic). The seven forests at and above 1700 m.a.s.l. may be classified as montane cloud forests, whereas the other two at 700 m.a.s.l. are lowland forests. A severe drought associated with an El Nin∼o–Southern Oscillation event occurred from late 1997 to early 1998. Mean absolute growth rates of stem diameter in each of four 2-year periods increased from smaller (4.8–10 cm diameter) to larger (_10 cm diameter) stems in each forest, decreased with increasing altitude on the same substrate, and were greater on non-ultrabasic than on ultrabasic substrate at the same altitudes. There were significant, concordant biennial variations in growth rates among the nine forests for both smaller and larger stems. The period of least growth included the drought in all forests for larger stems. Overall, the patterns of variation were similar among forests on different substrates at the same altitude (especially for larger stems), suggesting climatic rather than edaphic control of tree growth. Growth rates exhibited a consistent pattern in that: (i) rates for individual stems changed substantially from pre-drought (1995–1997) to drought periods (1997–1999), and (ii) the altered growth rates persisted during post-drought periods (1999–2001 and 2001–2003), especially in the montane forests. […]
  • Goro Hanya, Shin ichiro Aiba Ecological Research 25 (6) 1081 -1090 2010年11月 [査読有り][通常論文]
     
    There have been few attempts to compare fruit productivity throughout the world, although this is indispensable for understanding the global variations in frugivore diversity. The purposes of this study are (1) to reveal the patterns in fruit fall in tropical and temperate forests, (2) to examine the environmental factors (location, climate, and total litterfall) affecting these patterns, and (3) to assess the effect of fruit fall on frugivore diversity by using bird and primate data. Fruit fall was compared among 53 forests, from around the equator to the cool-temperate zone at 62°N, in Asia, Africa, North and South America, and Australia. Average ± SD of fruit fall (kg/ha/year) was 454 ± 258 in tropical, and 362 ± 352 in temperate forests. Fruit fall was exceptionally high in Australia (812 ± 461). When Australia was excluded, fruit fall significantly decreased with increasing absolute latitude and altitude, and fruit fall in tropical forest was 1.7 times larger than that in temperate forests (265 ± 227). Total litterfall affected fruit fall significantly, explaining 32, 28, and 64% of the variations of fruit fall in the entire data, tropical data, and temperate data, respectively. The fruit fall/litterfall ratio did not differ between temperate and tropical forests but was significantly higher in Australia than in other regions. Among climatic parameters (annual temperature, precipitation, actual evapotranspiration), a positive relationship was found between temperature and fruit fall in the entire dataset and within temperate forests. Fruit fall seemed to explain the temperate/tropical difference in frugivorous primate diversity to some extent, but not for frugivorous bird diversity. This study shows that the difference in fruit fall in tropical and temperate forests is smaller than that in frugivore diversity, and that it could explain at least part of the frugivore diversity. © 2010 The Ecological Society of Japan.
  • 今井伸夫, 清野達之, 相場慎一郎, 武生雅明, 北山兼弘 日本生態学会大会講演要旨集 57th 263 2010年03月15日 [査読無し][通常論文]
  • J. W F Slik, Shin Ichiro Aiba, Francis Q. Brearley, Chuck H. Cannon, Chuck H. Cannon, Olle Forshed, Kanehiro Kitayama, Hidetoshi Nagamasu, Reuben Nilus, John Payne, Gary Paoli, Gary Paoli, Axel D. Poulsen, Niels Raes, Douglas Sheil, Kade Sidiyasa, Eizi Suzuki, Johan L C, H van Valkenburg Global Ecology and Biogeography 19 (1) 50 -60 2010年01月 [査読有り][通常論文]
     
    Aim: Tropical forests have been recognized as important global carbon sinks and sources. However, many uncertainties about the spatial distribution of live tree above-ground biomass (AGB) remain, mostly due to limited availability of AGB field data. Recent studies in the Amazon have already shown the importance of large sample size for accurate AGB gradient analysis. Here we use a large stem density, basal area, community wood density and AGB dataset to study and explain their spatial patterns in an Asian tropical forest. Location: Borneo, Southeast Asia. Methods: We combined stem density, basal area, community wood density and AGB data from 83 locations in Borneo with an environmental database containing elevation, climate and soil variables. The Akaike information criterion was used to select models and environmental variables that best explained the observed values of stem density, basal area, community wood density and AGB. These models were used to extrapolate these parameters across Borneo. Results: We found that wood density, stem density, basal area and AGB respond significantly, but differentially, to the environment. AGB was only correlated with basal area, but not with stem density and community wood specific gravity. Main conclusions: Unlike results from Amazonian forests, soil fertility was an important positive correlate for AGB in Borneo while community wood density, which is a main driver of AGB in the Neotropics, did not correlate with AGB in Borneo. Also, Borneo's average AGB of 457.1 Mg ha. -1 was . c. 60% higher than the Amazonian average of 288.6 Mg ha. -1. We find evidence that this difference might be partly explained by the high density of large wind-dispersed Dipterocarpaceae in Borneo, which need to be tall and emergent to disperse their seeds. Our results emphasize the importance of Bornean forests as carbon sinks and sources due to their high carbon storage capacity. © 2009 Blackwell Publishing Ltd.
  • J. W Ferry Slik, J. W Ferry Slik, Niels Raes, Shin Ichiro Aiba, Francis Q. Brearley, Charles H. Cannon, Charles H. Cannon, Erik Meijaard, Hidetoshi Nagamasu, Reuben Nilus, Gary Paoli, Gary Paoli, Axel D. Poulsen, Douglas Sheil, Eizi Suzuki, Johan L C, H Van Valkenburg, Campbell O. Webb, Campbell O. Webb, Peter Wilkie, Stephan Wulffraat Diversity and Distributions 15 (3) 523 -532 2009年05月 [査読有り][通常論文]
     
    Aim Identify environmental correlates for tropical tree diversity and composition. Location Borneo, Southeast Asia. Methods A GIS-environmental database with 5 arc minute (c. 10 × 10 km) resolution was combined with tree inventory data. Tree diversity, phylogenetic diversity (PD) and the two main compositional gradients were determined for 46 tree inventories. Akaike's information criterion and a data jackknifing procedure were used to select 50 explanatory models for diversity and composition gradients. The average of these models was used as our final diversity and compositional model. We applied Moran's I to detect spatial autocorrelation of residuals. Results Tree diversity, PD and the two main compositional gradients in Borneo were all significantly correlated with the environment. Tree diversity correlated negatively with elevation, soil depth, soil coarseness (texture) and organic carbon content, whereas it correlated positively with soil C:N ratio, soil pH, moisture storage capacity and annual rainfall. Tree PD was correlated positively with elevation and temperature seasonality and was largely determined by gymnosperms. However, angiosperm PD also correlated positive with elevation. Compositional patterns were strongly correlated with elevation but soil texture, cation-exchange-capacity, C:N ratio, C and N content and drainage were also important next to rainfall seasonality and El Niño Southern Oscillation drought impact. Main conclusions Although elevation is the most important correlate for diversity and compositional gradients in Borneo, significant additional variability is explained by soil characteristics (texture, carbon content, pH, depth, drainage and nutrient status) and climate (annual rainfall, rainfall seasonality and droughts). The identified environmental correlates for diversity and composition gradients correspond to those found in other tropical regions of the world. Differences between the regions are mainly formed by differences in the relative importance of the environmental variables in explaining diversity and compositional gradients. © 2009 Blackwell Publishing Ltd.
  • Aiba, S, Hanya, G, Tsujino, R, Takyu, M, Seino, T, Kimura, K, Kitayama, K Ecological Research 22 (3) 439 -450 2007年05月 [査読有り][通常論文]
     
    We examined the basal area of two life forms (conifers vs. broadleaf trees) along elevational gradients on Yakushima Island, Japan and on two series of geological substrate on Mount Kinabalu, Borneo. On Yakushima, total stand basal area abruptly increased from 700 to 1,050 m in accordance with the high dominance of conifers, indicating the presence of additive basal area of conifers in conifer-broadleaf mixed forests at higher elevations (1,050-1,300 m). Along two substrate series on Kinabalu, some forests at higher elevations (1,860-3,080 m) showed relatively high dominance of conifers, but conifer basal area did not appear to be additive. Conifers were emergents above the canopy of broadleaf trees in mixed forests on Yakushima, but two life forms usually coexisted in the single-story canopy in mixed forests on Kinabalu. Litterfall rate as a surrogate of productivity decreased with decreasing temperature along elevation on both the sites, but the rate of decrease was slower on Yakushima, where mixed forests at higher elevations showed relatively high rates. Thus, we suggest that additive basal area of conifers was linked to their emergent status, and that it enhanced productivity by complementary use of light by two life forms that occupy different stories. On Yakushima, typhoons are a major disturbance, but do not severely limit the height growth of conifers, allowing the development of two-story mixed forests. On Kinabalu, a major disturbance is El Niño-driven drought, and hydraulic limitation to tree height may explain the non-additive and non-emergent nature of conifers. © 2007 The Ecological Society of Japan.
  • Stand-level defoliation ratio by herbivorous insects along altitudes, between geological features, and between topography on Mt. Kinabalu, Borneo
    Suzuki, S, Kitayama, K, Aiba, S, Takyu, M, Kikuzawa, K Proceedings IUFRO Kanazawa 2003 International Symposium "Forest Insect Population Dynamics and Host Influences" 116 -119 2006年 [査読無し][通常論文]
  • Floristic composition, stand structure, and above-ground biomass of the tropical rain forests of Deramakot and Tangkulap Forest Reserve in Malaysia under different forest managements.
    Seino T, Takyu M, Aiba S, Kitayama K, Ong R In: Lee Y.F., Chung A.Y., & Kitayama K. (eds) The 2nd Workshop on Synergy between Carbon Management and Biodiversity Conservation in Tropical Rain Forests 2006年 [査読有り][通常論文]
  • Shin Ichiro Aiba, Masaaki Takyu, Kanehiro Kitayama Ecological Research 20 (3) 279 -286 2005年05月 [査読有り][通常論文]
     
    We studied the dynamics of nine tropical rainforests on Mount Kinabalu, Borneo, at four elevations (700, 1,700, 2,700 and 3,100 m) on various edaphic conditions for four 2-year periods over 8 years (1995-2003), and examined the relationships with above-ground productivity. Mean growth rate of stem diameter, basal area turnover rate and estimated recruitment rate (using growth rate and size distribution) correlated with productivity among the nine forests in all periods. These rates based on growth rates of surviving stems appeared to be good measures of stand turnover. However, observed recruitment rate and mortality (and turnover rate as mean of these rates) based on direct observation of recruits and deaths did not correlate with productivity in some periods. These rates may not be useful as measures of stand turnover given small sample size and short census interval because they were highly influenced by stochastic fluctuation. A severe drought associated with the 1997-1998 El Niño event inflated mortality and depressed mean growth rate, recruitment rate and basal area turnover rate, but had little effect on the correlations between these rates (except mortality) and productivity. Across broad elevational and edaphic gradients on Mount Kinabalu, forest turnover, productivity and species richness correlated with each other, but the causal interpretation is difficult given the different histories and species pools among forests at different elevations. © The Ecological Society of Japan 2005.
  • Masaaki Takyu, Yasuhiro Kubota, Shin Ichiro Aiba, Tatsuyuki Seino, Takashi Nishimura Ecological Research 20 (3) 287 -296 2005年05月 [査読有り][通常論文]
     
    We examined effects of seasonality of climate and dominant life form (evergreen/deciduous, broadleaf/coniferous) together with energy condition on species diversity, forest structure, forest dynamics, and productivity of forest ecosystems by comparing the patterns of changes in these ecosystem attributes along altitudinal gradients in tropical regions without seasonality and along a latitudinal gradient from tropical to temperate regions in humid East Asia. We used warmth index (temperature sum during growing season, WI) as an index of energy condition common to both altitudinal and latitudinal gradients. There were apparent differences in patterns of changes in the ecosystem attributes in relation to WI among four forest formations that were classified according to dominant life form and climatic zone (tropical/temperate). Many of the ecosystem attributes - Fisher's alpha of species-diversity indices, maximum tree height and stem density, productivity [increment rate of aboveground biomass (AGB)], and population and biomass turnover rates - changed sharply with WI in tropical and temperate evergreen broad-leaved forests, but did not change linearly or changed only loosely with WI in temperate deciduous broad-leaved and evergreen coniferous forests. Values of these ecosystem attributes in temperate deciduous broad-leaved and evergreen coniferous forests were higher (stem density was lower) than those in tropical and temperate evergreen broad-leaved forests under colder conditions (WI below 100°C). Present results indicate that seasonality of climate and resultant change in dominant life form work to buffer the effects of energy reduction on ecosystem attributes along latitudinal gradients. © The Ecological Society of Japan 2005.
  • Shin Ichiro Aiba, Masaaki Takyu, Kanehiro Kitayama Forest Ecosystems and Environments: Scaling Up from Shoot Module to Watershed 41 -48 2005年 [査読有り][通常論文]
     
    We studied the dynamics of nine tropical rainforests on Mount Kinabalu, Borneo, at four elevations (700, 1,700, 2,700 and 3,100 m) on various edaphic conditions for four 2-year periods over 8 years (1995-2003), and examined the relationships with above-ground productivity. Mean growth rate of stem diameter, basal area turnover rate and estimated recruitment rate (using growth rate and size distribution) correlated with productivity among the nine forests in all periods. These rates based on growth rates of surviving stems appeared to be good measures of stand turnover. However, observed recruitment rate and mortality (and turnover rate as mean of these rates) based on direct observation of recruits and deaths did not correlate with productivity in some periods. These rates may not be useful as measures of stand turnover given small sample size and short census interval because they were highly influenced by stochastic fluctuation. A severe drought associated with the 1997-1998 El Niño event inflated mortality and depressed mean growth rate, recruitment rate and basal area turnover rate, but had little effect on the correlations between these rates (except mortality) and productivity. Across broad elevational and edaphic gradients on Mount Kinabalu, forest turnover, productivity and species richness correlated with each other, but the causal interpretation is difficult given the different histories and species pools among forests at different elevations. © The Ecological Society of Japan.
  • Masaaki Takyu, Yasuhiro Kubota, Shin Ichiro Aiba, Tatsuyuki Seino, Takashi Nishimura Forest Ecosystems and Environments: Scaling Up from Shoot Module to Watershed 49 -58 2005年 [査読有り][通常論文]
     
    We examined effects of seasonality of climate and dominant life form (evergreen/deciduous, broadleaf/coniferous) together with energy condition on species diversity, forest structure, forest dynamics, and productivity of forest ecosystems by comparing the patterns of changes in these ecosystem attributes along altitudinal gradients in tropical regions without seasonality and along a latitudinal gradient from tropical to temperate regions in humid East Asia. We used warmth index (temperature sum during growing season, WI) as an index of energy condition common to both altitudinal and latitudinal gradients. There were apparent differences in patterns of changes in the ecosystem attributes in relation to WI among four forest formations that were classified according to dominant life form and climatic zone (tropical/temperate). Many of the ecosystem attributes-Fisher's alpha of species-diversity indices, maximum tree height and stem density, productivity [increment rate of aboveground biomass (AGB)], and population and biomass turnover rates-changed sharply with WI in tropical and temperate evergreen broad-leaved forests, but did not change linearly or changed only loosely with WI in temperate deciduous broad-leaved and evergreen coniferous forests. Values of these ecosystem attributes in temperate deciduous broad-leaved and evergreen coniferous forests were higher (stem density was lower) than those in tropical and temperate evergreen broad-leaved forests under colder conditions (WI below 100°C). Present results indicate that seasonality of climate and resultant change in dominant life form work to buffer the effects of energy reduction on ecosystem attributes along latitudinal gradients. © The Ecological Society of Japan.
  • Kanehiro Kitayama, Shizuo Suzuki, Masato Hori, Masaaki Takyu, Shin Ichiro Aiba, Noreen Majalap-Lee, Kihachiro Kikuzawa Oecologia 140 (2) 335 -339 2004年07月 [査読有り][通常論文]
     
    We investigated if tropical rainforest trees produced more-lignified leaves in less productive environments using forests on Mount Kinabalu, Borneo. Our investigation was based on two earlier suggestions that slower litter decomposition occurs under less productive forests and that trees under resource limitation invest a large amount of carbon as lignin as a defense substance to minimize the loss from herbivores. When nine forests at different altitudes (700-3100 m) and soil conditions (derived from sedimentary or ultrabasic rocks) but with the same gentle relief position were compared, the concentrations of leaf-litter lignin were positively correlated with litterfall rates and leaf-litter nitrogen concentrations. These patterns would be reinforced in intact leaves if the effects of resorption at the time of leaf shedding were taken into account, because greater magnitude of resorption of mobile elements but not of lignin would occur in less productive environments (i.e. dilution of lignin in intact leaves). These results did not support earlier suggestions to explain the variation of leaf-litter lignin. Instead, we suggest that lower lignin contents are adaptive to recycle minerals without retarding decomposition in less productive environments. © Springer-Verlag 2004.
  • Kanehiro Kitayama, Shin Ichiro Aiba, Masaaki Takyu, Noreen Majalap, Rota Wagai Ecosystems 7 (3) 259 -274 2004年04月 [査読有り][通常論文]
     
    We compared phosphorus (P) dynamics and plant productivity in two montane tropical rain forests (Mount Kinabalu, Borneo) that derived from similar parent materials (largely sedimentary rocks) and had similar climates but differed in terms of soil age. The younger site originated from Quaternary colluvial deposits, whereas the older site had Tertiary-age material. The older site had a distinctive spodic horizon, reduced levels of labile inorganic soil P, higher concentrations of recalcitrant organic soil P, and lower rates of net soil N mineralization. P fertilization led to soil nitrogen (N) immobilization in the P-deficient soil, indicating that soil N mineralization was limited by P at the P-deficient older site. Mean foliar nutrient concentration (on both a weight and an area basis) was similar at the two sites for all elements except P, which was lower at the older site. Aboveground net primary production (ANPP) was lower at the older site than at the younger one; this difference could be explained by the reduced availability of P and N (as down-regulated by P) at the older site. The relatively ample allocation of P and N to leaves, despite the reduced availability at the P-deficient old site, was attributable to its high resorption efficiency. High resorption resulted in lower concentrations of elements in leaf litter - that is, less decomposable low-quality litter. On the other hand, the concentration of leaf litter lignin was considerably lower at the older site; this appeared to be a de facto adaptive mechanism to avoid retarding litter decomposition.
  • Shin Ichiro Aiba, Kanehiro Kitayama, Masaaki Takyu Plant Ecology 174 (1) 147 -161 2004年 [査読有り][通常論文]
     
    Habitat associations with topography and canopy structure of 42 abundant tree species were studied in a 2.74-ha plot of tropical montane forest on Mount Kinabalu, Borneo. Many of these species belong to the same higher taxa including eight families and four genera. Analysis of intraspecific spatial distributions for stems ≥ 10 cm diameter revealed that 28 species (including all six species of Fagaceae) showed aggregated distributions at the 100-m 2 and/or 400-m 2 scales, and that 20 species showed habitat associations with topography by torus-translation tests; 17 species showed both characteristics. Species' associations with the local canopy structure were characterized by crown position index (CPI), which was defined relative to neighbour trees. The CPI differed greatly among individual stems at 10-40 cm diameter, and 19 species showed significantly different frequencies of crowns exposed vertically versus those shaded beneath the canopy. Mean growth rates at 10-40 cm diameter and size distributions of species were not related to topographic associations, but were explained by the associations with canopy structure; species with more exposed crowns grew faster and had less positively skewed distributions. Diversity in habitat associations was manifest between two genera (Syzygium and Tristaniopsis) in the family Myrtaceae and among species in these genera, but was less evident in other families and two genera (Garcinia and Lithocarpus).
  • Masaaki Takyu, Shin Ichiro Aiba, Kanehiro Kitayama, Kanehiro Kitayama Oecologia 134 (3) 397 -404 2003年02月 [査読有り][通常論文]
     
    We have examined how the structure and function of a forest ecosystem change with topography (lower-slope versus ridge) and how the changes are modified by nutrient availability depending on geological substrate (Quaternary and Tertiary sedimentary rocks and ultrabasic rock) in the tropical montane rain forests of Mt. Kinabalu (Borneo) where climate is humid and aseasonal. Reflecting the difference in site age and parent rock, the pool size of soluble-P and inorganic-N in topsoils decreased from Quaternary sedimentary >Tertiary sedimentary >ultrabasic rock on the lower-slope, and they decreased from the lower-slope to the ridge on all substrates. Forest structural attributes [stature, above-ground biomass, and leaf area index (LAI)] decreased in the order of Quaternary sedimentary >Tertiary sedimentary >ultrabasic rock in association with soil nutrients on the lower-slopes, and decreased upslope consistently on each of the three substrates. Functional attributes [above-ground net primary productivity (ANPP) and decomposition rate] demonstrated similar patterns to structure. ANPP significantly correlated with LAI among the six sites, while net assimilation rate (ANPP divided by LAI assuming an even productivity between above vs below-ground system) was nearly constant. Therefore, ANPP could be explained primarily by LAI. Topographical change in LAI could be explained by leaf mass per area (LMA) combined with stand-level leaf biomass. LMA increased upslope on all substrates in association with the decrease in individual leaf area. Stand-level leaf biomass decreased upslope on all substrates but the Tertiary sedimentary rock. Our study demonstrated that topography and geological substrates interactively affected forest structure and processes. The effect of topography on forest structure and processes was greater on nutrient-rich substrates than on poor substrates, and the effect of geological substrate was greater on lower-slopes than on ridges.
  • 武生雅明, 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨集 49th 172 2002年03月25日 [査読無し][通常論文]
  • 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨集 49th 277 2002年03月25日 [査読無し][通常論文]
  • 鈴木静男, 北山兼弘, 相場慎一郎, 武生雅明, 菊沢喜八郎 日本生態学会大会講演要旨集 49th 274 2002年03月25日 [査読無し][通常論文]
  • Shin Ichiro Aiba, Kanehiro Kitayama, Kanehiro Kitayama Journal of Tropical Ecology 18 215 -230 2002年03月 [査読無し][通常論文]
     
    We examined the effects of the 1997-98 El Niño drought on nine rain forests of Mount Kinabalu, Borneo, at four altitudes (700, 1700, 2700 and 3100 m) on contrasting geological substrata (ultrabasic versus non-ultrabasic). Measurements of rainfall and atmospheric aridity indicated that the departure from normal conditions during the drought became greater with increasing altitude. During 1997-99 (drought period) compared to 1995-97 (pre-drought period), median growth rates of stem diameter of trees decreased for both smaller (4.8-10 cm) and larger (≥ 10 cm) diameter classes in the six upland forests (≥ 2700 m on ultrabasic substrata and ≥ 1700 m on non-ultrabasic substrata), but for neither diameter class in the other forests. The majority of species decreased or did not change growth rates during 1997-99, whereas some did increase. Tree mortality increased during 1997-99, at the larger diameter class in the two lowland forests (700 m) on both substrata, anti at least at the smaller diameter class in the four upland forests (≥ 1700 m) on non-ultrabasic substrata. In two of these upland forests, mortality was restricted to particular understorey species. Mortality did not significantly increase in the three upland forests (≥ 1700 m) on ultrabasic substrata; this suggests that the adaptation to nutrient-poor soils might have provided the resistance to drought.
  • Aiba, S, Kitayama, K Journal of Tropical Ecology 18 (2) 215 -230 2002年 [査読有り][通常論文]
     
    We examined the effects of the 1997-98 El Niño drought on nine rain forests of Mount Kinabalu, Borneo, at four altitudes (700, 1700, 2700 and 3100 m) on contrasting geological substrata (ultrabasic versus non-ultrabasic). Measurements of rainfall and atmospheric aridity indicated that the departure from normal conditions during the drought became greater with increasing altitude. During 1997-99 (drought period) compared to 1995-97 (pre-drought period), median growth rates of stem diameter of trees decreased for both smaller (4.8-10 cm) and larger (≥ 10 cm) diameter classes in the six upland forests (≥ 2700 m on ultrabasic substrata and ≥ 1700 m on non-ultrabasic substrata), but for neither diameter class in the other forests. The majority of species decreased or did not change growth rates during 1997-99, whereas some did increase. Tree mortality increased during 1997-99, at the larger diameter class in the two lowland forests (700 m) on both substrata, anti at least at the smaller diameter class in the four upland forests (≥ 1700 m) on non-ultrabasic substrata. In two of these upland forests, mortality was restricted to particular understorey species. Mortality did not significantly increase in the three upland forests (≥ 1700 m) on ultrabasic substrata; this suggests that the adaptation to nutrient-poor soils might have provided the resistance to drought.
  • Journal of Tropical Ecology 18 215 -230 2002年 [査読無し][通常論文]
  • Kanehiro Kitayama, Kanehiro Kitayama, Shin Ichiro Aiba Journal of Ecology 90 (1) 37 -51 2002年 [査読有り][通常論文]
     
    1. We measured above-ground net primary productivity (ANPP) and ecosystem structure and processes in eight rain forest stands at four elevations (700, 1700, 2700 and 3100 m) and on two geological substrates (sedimentary vs. ultrabasic rock) on Mount Kinabalu, Borneo. 2. All ultrabasic sites had smaller pools of total soil phosphorus (P) and of labile inorganic P than did the sedimentary sites at the same altitudes. We predicted that the magnitude of altitudinal changes in ANPP would be less on ultrabasic than on sedimentary substrates, reflecting lower temperature dependency of ANPP under stronger P limitation. 3. Although ANPP declined with increasing altitude on both substrates, the slopes of the two regression lines were similar. The intercept was, however, marginally greater on sedimentary than on ultrabasic substrate. 4. Stand-level nutrient-use efficiencies (the ratio of litterfall mass to nutrient return) for N and P were only affected by altitude on ultrabasic substrate where they increased exponentially. Mean foliar N and P contents per unit leaf area of the canopy species increased with altitude on both substrates, but differed between substrates at the same altitude only for P (lower on ultrabasic). 5. Leaf area index (LAI) decreased upslope on both substrates. We assumed that half of primary production was allocated below-ground in order to evaluate stand level net assimilation rate (NAR). This was nearly constant on sedimentary substrate, but declined linearly with increasing altitude on ultrabasic substrate, where it may have to be added to LAI to explain ANPP patterns. 6. We suggest that on sedimentary substrate trees may be able to maintain NAR under colder environments by increasing foliar N and P per unit leaf area, but P deficiency prevents them from adjusting on ultrabasic substrate.
  • Masaaki Takyu, Shin Ichiro Aiba, Kanehiro Kitayama Plant Ecology 159 (1) 35 -49 2002年 [査読有り][通常論文]
     
    Species composition and forest structure change with topography. However, mechanisms for topographical vegetation changes are still not well understood, because a topographical gradient is a complex environmental gradient inclusive of many factors. The foot of Mt. Kinabalu is covered with three types of geological substrates, i.e. Quaternary and Tertiary sedimentary rocks and ultrabasic (serpentine) rock. Quaternary and Tertiary sedimentary rocks are different in site age, but controlled in primary minerals. Tertiary sedimentary and ultrabasic rocks are contrasting in primary minerals, but are comparable in age. This setting provides an opportunity to examine the vegetation differentiation along topographical gradients that are contrasting in major-nutrient supply due to the difference in site age and parent rock. We established a total of nine study plots by choosing three topographical units (ridge, middle- and lower-slope) on each substrate in the tropical lower montane forest. Pool size and supply of soil N and P decreased upslope on each substrate, and the magnitude of the reduction from slope to ridge decreased in the order of Quaternary sedimentary > Tertiary sedimentary > ultrabasic rock. Between-substrate difference in soil nutrient condition was greater on the lower-slopes than the ridges. Maximum tree size decreased and stem density increased upslope on each substrate. Detrended con'espondence analysis demonstrated that species composition also changed along topographical gradients on all substrates. Howeven the magnitude of topographical changes in forest structure and species composition varied with substrate and decreased from Quaternary sedimentary > Tertiary sedimentary > ultrabasic rock. The greatest between-substrate difference in vegetation occurred on the lower-slopes. Accordingly, our results suggest that the magnitude of vegetation changes due to topography becomes smaller with decreasing pool size and supply of nutrients.
  • 北山兼弘, 相場慎一郎, 武生雅明 日本生態学会大会講演要旨集 48th 183 2001年03月22日 [査読無し][通常論文]
  • 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨集 48th 109 2001年03月22日 [査読無し][通常論文]
  • 武生雅明, 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨集 48th 199 2001年03月22日 [査読無し][通常論文]
  • Shin Ichiro Aiba, David A. Hill, Naoki Agetsuma Forest Ecology and Management 140 (2-3) 163 -175 2001年01月15日 [査読有り][通常論文]
     
    In order to infer successional changes in structure, species composition and diversity of warm-temperate forest, we compared secondary stands regenerating after clear-felling (41-64-years old) with old-growth stands at altitudes between 300 and 800 m on Yakushima Island, southern Japan. Stem density and maximum stem diameter differed between secondary and old-growth stands, but basal area and aboveground biomass did not. At lower altitudes, the dominant species in old-growth stands with a strong sprouting capacity (Castanopsis cuspidata) also dominated secondary stands, and species composition of secondary and old-growth stands was similar. At higher altitudes, by contrast, the dominant species in old-growth stands (Distylium racemosum) had little sprouting capacity and was poorly represented in diverse secondary stands, which were dominated by Castanopsis or other less abundant species. Secondary stands had greater species diversity (Shannon-Wiener index) than old-growth stands, particularly at higher altitudes. This was due to greater species richness resulting from higher stem density per area, but not to greater evenness. We grouped the component species that share ecologically similar traits into four guilds (fagaceous, primary evergreen, secondary evergreen and deciduous species). Secondary stands were characterized by greater numbers of deciduous and secondary evergreen species. We concluded that different sprouting capacities of dominant species and different regeneration traits among guilds are responsible for the change in species composition and diversity during succession. © 2001 Elsevier Science B.V.
  • Kanehiro Kitayama, Noreen Majalap-Lee, Shin Ichiro Aiba, Shin Ichiro Aiba Oecologia 123 (3) 342 -349 2000年05月 [査読有り][通常論文]
     
    We studied soil phosphorus (P) fractionation and P-use efficiencies (PUEs) of rainforests along altitudinal gradients (700-3100 m) on two types of parental rocks (sedimentary versus ultrabasic) on Mount Kinabalu, Borneo. Sedimentary rocks were known to contain more quartz (which does not adsorb P) than ultrabasic rocks. The pool (top 30 cm) of total P was always greater on sedimentary (ranging from 34.9 to 72.6 g m-2) than on ultrabasic (9.0-29.2 g m-2) rocks at comparable altitudes. Accordingly, the pools of organic P and labile inorganic P were always greater on sedimentary than on ultrabasic rocks. The pool of primary mineral, calcium P increased upslope from 1.7 to 4.3 g m-2 on sedimentary rock, suggesting that the altitudinal sequence of the sites reflected a decreasing magnitude of soil weathering upslope. The pool of calcium P on ultrabasic rock did not vary consistently with altitude (1.2-2.8 g m-2), probably reflecting the greater between-site variability of primary mineral P in parent rocks. When all sites were compared, the pool of most labile, bicarbonate-extracted inorganic P increased (ranging from 0.02 to 1.85 g m-2) with increasing calcium P. Calcium P was therefore considered to be an important P source to the biota on Kinabalu. Gross patterns in the variation of PUE (indexed as the reciprocal of the P concentration in litter) were best explained by the pool size of actively cycling P (total P minus occluded inorganic P). PUE, however, demonstrated distinct altitudinal patterns to generate an intricate conrol of P use pattern by soil P pools and altitude.
  • 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨集 47th 95 2000年03月21日 [査読無し][通常論文]
  • 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨集 46th 210 1999年03月22日 [査読無し][通常論文]
  • 武生雅明, 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨集 46th 210 1999年03月22日 [査読無し][通常論文]
  • 北山兼弘, 相場慎一郎 日本生態学会大会講演要旨集 46th 209 1999年03月22日 [査読無し][通常論文]
  • Aiba, S, Kitayama, K Plant Ecology 140 (2) 139 -157 1999年 [査読有り][通常論文]
     
    We studied forest structure, composition and tree species diversity of eight plots in an environmental matrix of four altitudes (700, 1700, 2700 and 3100 m) and two types of geological substrates (ultrabasic and non-ultrabasic rocks) on Mount Kinabalu, Borneo. On both substrate series, forest stature, mean leaf area and tree species diversity (both ≥ 4.8 cm and ≥ 10 cm diameter at breast height [dbh]) decreased with altitude. The two forests on the different substrate series were similar at 700 m in structure, generic and familial composition and tree species diversity, but became dissimilar with increasing altitude. The decline in stature with altitude was steeper on the ultrabasic substrates than on the non-ultrabasic substrates, and tree species diversity was generally lower on ultrabasic substrates than on non-ultrabasic substrates at ≥ 1700 m. The forests on non-ultrabasic substrates at higher altitudes and those on ultrabasic substrates at the lower altitudes were similar in dbh versus tree height allometry, mean leaf area, and generic and familial composition at ≥ 1700 m. These contrasting patterns in forest structure and composition between the two substrate series suggested that altitudinal change was compressed on the ultrabasic substrates compared to the non-ultrabasic substrates. Tree species diversity was correlated with maximum tree height and estimated aboveground biomass, but was not with basal area, among the eight study sites. We suggest that forests with higher tree species diversity are characterized by greater biomass allocation to height growth relative to trunk diameter growth under more productive environment than forests With lower tree species diversity.
  • Kanehiro Kitayama, Kanehiro Kitayama, Shin Ichiro Aiba, Noreen Majalap-Lee, Masahiko Ohsawa Ecological Research 13 (3) 301 -312 1998年12月 [査読有り][通常論文]
     
    Mt Kinabalu, Borneo, is characterized by a deep elevational gradient and mosaics o f geological substrates. We chose a pair of two geological substrates (sedimentary vs ultrabasic) at five altitudes (800, 1400, 2100, 2700 and 3100 m a.s.1.). We investigated soil nitrogen ON) mineralization and nitrification rates using an incubation technique to assay the pattern and control of soil N status in this environmental matrix. In situ net mineralization rates decreased with elevation on both substrates. The decreasing pattern was linear across altitudes on ultrabasic rock, whereas on sedimentary rock it was depressed in the middle slope wet cloud zone. Sedimentary sites in this zone had low soil redox potential values and this anoxic soil condition might be related to slow N mineralization. The in site rates were significantly greater (P<0.05, ANOVA) on sedimentary than on ultrabasic rock at the same altitudes except in the cloud zone. Net mineralization rates of the soils that were collected from different elevations and incubated in the same conditions were statistically invariable (P>0.05) among the original elevations for sedimentary rock, but were variable (P<0.05) for ultrabasic rock. Those of the soils that were collected from the same elevation and incubated at different elevations decreased significantly across altitudes (P<0.05) for sedimentary rock, while they were invariable (P>0.05) for ultrabasic rock. Thus, temperature had stronger effects on net N mineralization on sedimentary rock, whereas inherent soil quality had stronger effects on ultrabasic rock. Controls of soil N mineralization might be different between the two substrates, leading to diverse biogeochemical site conditions on Kinabalu.
  • 北山 兼弘, 相場 慎一郎, 木村 一也 Tropics 7 (3/4) 309 -317 1998年08月 [査読無し][通常論文]
  • 相場慎一郎, 北山兼弘 日本生態学会大会講演要旨集 44th 31 1997年03月 [査読無し][通常論文]
  • Aiba, S, Kohyama, T Journal of Ecology 85: 85 (5) 611 -624 1997年 [査読有り][通常論文]
     
    1. We examined architectural and life-history traits of 14 abundant non-pioneer tree species at various size classes in a warm-temperate rain forest on Yakushima Island, southern Japan. The 14 species were categorized according to maximum attainable size (five canopy, seven subcanopy and two understorey species). 2. Within each maximum-size category, the relative frequency of trees of 2-8 cm d.b.h. (trunk diameter at breast height) in gaps compared with closed-canopy stands differed between species. In the closed-canopy stands, the positions of the crowns in the heterogeneous canopy differed between species within each of the canopy and sub-canopy categories at 8-40 cm d.b.h. 3. We regressed the relationship between d.b.h. and crown architecture by a non-linear allometric equation for the 14 species. There was a continuum from wide-crown species to narrow-crown species within canopy and subcanopy categories at 2-16 cm d.b.h. The two understorey species were wide-crown species throughout their ontogeny. 4. Interspecific differences in both rate of increase of d.b.h. and mortality over 10 years (1983-93) were detected within the canopy and subcanopy categories. 5. Principal component analysis based on five architectural and life-history traits revealed species differentiation within the canopy and subcanopy categories, reflecting a trade-off between responsiveness to increasing light in narrow-crown species and shade tolerance in wide-crown species. Multiple regression analyses suggested that most of these traits could be predicted by the light environments experienced by species rather than by species' maximum sizes. We concluded that species differentiation in this community was primarily related to different regeneration behaviour in gaps by trees of 2-8 cm d.b.h., and to different space occupation in the heterogeneous canopy at 8-16 cm d.b.h.
  • Crown architecture and life-history traits of 14 tree species in a warm-temperate rain forest : significance of spatial heterogeneity (共著)
    Journal of Ecology 85 611 -624 1997年 [査読無し][通常論文]
  • T. Kohyama, S. Aiba Tropics 6 (4 Spec. Iss.) 383 -392 1997年 [査読有り][通常論文]
     
    We describe the structural and dynamic feature of warm-temperate rain forests in foothill and lower montane zones of Yakushima Island, with particular reference to their potential of self-restoration. Forest-canopy dominant is Distylium racemosum of Hamamelidaceae. Codominant species belong to Fagaceae, Lauraceae, Symplocaceae, and Theaceae. Typical primary forest stand is characterized by high biomass stock (ca. 300 t/ha) relative to short canopy stature (ca. 20 m). Though the forest is repeatedly disturbed by typhoons, the gap-area ratio in primary stands is less than 10%. Mortality amounted ca. 0.02 per year suggesting 50-year turnover of trees. On the basis of dynamic data from permanent plots for more than 10 years (mortality, recruitment rate and size growth rate), observed size structure was sufficiently reconstructed as a steady state. Allometric and architectural differentiations among the 14 abundant species are changed along their life history. Secondary stands of warm-temperate rain forest are distributed near inhabited land. Majorities of secondary stand trees are coppice-origin primary stand species, while accompanied by deciduous pioneer trees. Tree growth rate of secondary stands is so high that the biomass-level recovery to the primary-stand state takes only 50 years after clear felling. Quick recovery of stands after clear-felling is also owing to the diversified traits among component tree species.
  • P. J. Bellingham, P. J. Bellingham, Takashi Kohyama, Takashi Kohyama, Shin Ichiro Aiba, Shin Ichiro Aiba Ecological Research 11 (3) 229 -247 1996年12月 [査読有り][通常論文]
     
    A powerful typhoon (Typhoon No. 13) affected stands of primary warm temperate rainforest in Yakushima, southern Japan, in 1993. Censuses in three sites 1-5 months after the typhoon showed low levels of mortality resulting from the typhoon (0.4-3.0% of stems). Stems killed by the typhoon were generally larger than surviving stems. Among surviving stems there were generally low levels of damage (e.g. 0. 5-1.3% of surviving stems lost crowns) and not all damage was widespread (e.g. defoliation was apparent only in one of three sites). The sizes of uprooted stems, stems that lost crowns and relatively undamaged stems were not different. Different species appeared to be damaged in different ways at different sites. Damage was most evident in higher altitude seaward sites but gap formation was more frequent in lower altitude sites near valley floors. After the typhoon the resultant gap area occupied 9.4% of one site and 8.6% of another, which is greater than that before the typhoon. Fresh sprouts were found on 17.35% of 2161 stems after the typhoon, including many apparently undamaged stems as well as those that were damaged. Species which sprouted most frequently were those that regenerate by seed least frequently in these forests; these species may maintain their relative abundance in part by sprouting. Most tree species in these forests may be relatively resistant to typhoons and there may be more opportunities for their regeneration following gap formation caused by the typhoon.
  • 大沢雅彦, 朱宮丈晴, 北山兼弘, 相場慎一郎 日本生態学会大会講演要旨集 43rd 178 1996年03月 [査読無し][通常論文]
  • 北山兼弘, 相場慎一郎, NOREEN M L, 大沢雅彦 日本生態学会大会講演要旨集 43rd 178 1996年03月 [査読無し][通常論文]
  • Shin Ichiro Aiba, Shin Ichiro Aiba, Takashi Kohyama, Takashi Kohyama Journal of Ecology 84 (2) 207 -218 1996年 [査読有り][通常論文]
     
    1 We studied stratification of tree species by analysing the allometry and demography of 14 abundant species in a warm-temperate rain forest on Yakushima Island, southern Japan. 2 We regressed relationships between trunk diameter at breast height (d.b.h.) and top height of trees using an expanded allometry which incorporates an upper limit to height. As trees grew up towards the canopy, individuals with the same d.b.h. were taller if they came from species with larger maximum height. This appeared to reflect a trade-off between height growth and lateral growth of crowns. Two canopy dominants continued to gain in d.b.h. after they had reached the canopy, while their height remained almost constant. 3 We examined size-specific patterns of relative growth rate of d.b.h. from a decade of field censuses. By fitting a Gompertz-type growth curve to size-specific growth of individual trees, we derived a projected potential maximum size for each species. The projected maximum size (both d.b.h. and height) was similar to the observed value for most species. Three canopy species exhibited larger projected maximum d.b.h. than observed values; the difference seemed to be due to mortality during the long period that each of these species resides in the canopy. 4 Understorey species recruited equally well as larger-growing species amongst the 14 studied species, although their tree mass increments per unit time were smaller. This suggests that understorey species have more effective recruiting capacity relative to vegetative growth.

共同研究・競争的資金等の研究課題

  • 西太平洋湿潤林における針葉樹の優占メカニズム:気候・土壌条件・光競争に基づく解明
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2019年04月 -2024年03月 
    代表者 : 相場 慎一郎, 北山 兼弘, 小野田 雄介
  • 窒素とリンの非対称性による多様な熱帯降雨林生態系の形成
    日本学術振興会:科学研究費助成事業 国際共同研究加速基金(国際共同研究強化(B))
    研究期間 : 2018年10月 -2024年03月 
    代表者 : 北山 兼弘, 相場 慎一郎, 辻井 悠希
     
    古い地質を持つボルネオ島などでは多様な熱帯降雨林生態系が成立している。その要因として、生元素として最も重要な窒素(N)とリン(P)の時空間的な非対称性が考えられる。NもPも生物の代謝や遺伝に普遍的に関わっているが、土壌風化プロセスの過程で、2つの元素のうちどちらかが欠乏する時空間的なパターンが生じる。さらに、元素欠乏に対して、樹木はNとPの間で異なる応答を示す。地球化学的なNとPのアンバランスと生物学的な応答の非対称性が組み合わさることにより、多様な生態系が形成される可能性が高い。本研究は、安定した地質を持ち、生物地球化学的な反応速度の速いボルネオ島熱帯降雨林を精査することにより、この独創的な仮説を検証する。本年度は以下を実施した。 マレーシア・サバ州(ボルネオ島)において、堆積岩起源の土壌上に成立している熱帯降雨林に複数の調査区を設定し、各調査区において土壌断面を5か所掘削し、表層の有機物層から下層に向けて土壌サンプルを採集した。採集した土壌は、サバ州内の共同研究施設に持ち帰って、前処理を行った。また、各調査区で優占樹種を選択し、陽葉と材サンプルを各種4個体から採集し、冷蔵して実験室に持ち帰った。一部サンプルは凍結乾燥し保管、さらに残りのサンプルについては熱風乾燥し粉砕後に日本に持ち帰った。陽葉と材の熱風乾燥サンプルの一部については、硫酸・過酸化水素により湿式灰化し、ICPにより全P濃度を、比色法により全N濃度を決定した。
  • ボルネオ熱帯林における伐採インパクトの違いが細根現存量の回復に及ぼす影響
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2018年04月 -2022年03月 
    代表者 : 宮本 和樹, 相場 慎一郎
     
    マレーシアなどの木材生産林の一部では、過去の無秩序な伐採により森林を荒廃させた反省から、持続可能な森林管理の実践的手法として低インパクト伐採が行われている。この方法は年間収穫量を従来の数十パーセント以下に抑えるほか、残存木の損傷や地表撹乱にも配慮している。低インパクト伐採の効果については、これまで森林地上部を中心に研究されてきた。しかし、伐採インパクトの違いが、森林地下部の現存量回復にどのような影響を及ぼすかという問題は、未解明なまま残されている。ボルネオ熱帯林における伐採インパクトの違いが細根現存量の回復時間に及ぼす影響とその要因を明らかにするため、マレーシア・サバ州のMaliau Basin森林保護区の原生林と、その周辺地域で過去に伐採が行われた森林を対象に、調査区設定のための候補地選定と樹木のサイズ計測を行った。混交フタバガキ林の原生林に設置した既存の調査プロットで毎木調査を実施したところ、原生林に特徴的なL字型のサイズ分布となっていた。また、胸高直径5 cm以上の個体を対象とした胸高断面積合計は48.8 m2/ha、地上部現存量は484.6 Mg/haと推定された。保護区周辺部の伐採が行われた森林では、地元の森林事務所スタッフらの情報提供により、2015年に低インパクト伐採が行われた場所と、2010年に従来型伐採が行われた場所を候補地として選定した。現地の状況を確認したところ、低インパクト伐採の森林は、場所によって状況が異なるものの原生林の樹種組成がある程度保たれているようであった。従来型伐採の森林では、多くの個体につる植物が繁茂し、個体を覆っているため、生育が阻害されている場所が目立った。以上のように、原生林、従来型伐採、低インパクト伐採の森林間比較を行うための基盤整備を進めた。
  • 固着性生物の種内変異が種間共存に及ぼす影響の長期観測に基づく解明
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2018年04月 -2021年03月 
    代表者 : 甲山 隆司, 金子 正美, 相場 慎一郎, 久保 拓弥, 野田 隆史, 工藤 岳
     
    (I) 野外調査: (I-1) 屋久島・照葉樹原生林の永久調査区の観測を行った。(I-2) 苫小牧の落葉広葉樹二次林調査区(1-ha)の20年目の再測を行った。また、苫小牧の常緑針葉樹・落葉広葉樹混交原生林調査区(4-ha)の22年目の再測を行った。 (II) データ解析: (II-1) 複数の森林プロットの長期観測データを用いて、個体成長による地上部現存量生産速度の推定を行い、種間変異を考慮しない場合の推定誤差を定量的に示した。ヒマラヤのAbies spectabilis個体群を対象に、個体レベルの幹直径(D)と樹高(H)データと、年輪解析によって得た幹直径成長から、集団平均のD-H曲線を用いて過去のHを個体毎に推定し、成長による現存量生産速度を推定する方法を開発し、論文発表した。(II-2) 函館の日浦海岸の潮間帯フジツボ群集の継続調査区において、1993年から1996年の間に撮影された写真画像を用いて、フジツボ2種の個体群の時間変化を記録する手法を確立した。 (III) 理論解析: 森林レベルの生産速度の、構成種間での分割特性を、熱帯多雨林と温帯林の観測データに基づいて解析し、種現存量と回転率の間に負のベキ乗関係が成立することを見出し、ベキ係数値の根拠を考察した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2011年04月 -2016年03月 
    代表者 : 相場 慎一郎, 北山 兼弘, 武生 雅明, 宮本 和樹, 清野 達之
     
    広葉樹が圧倒的に優占する熱帯でも、山地や特殊な立地条件(ヒース林など)には、マキ科やナンヨウスギ科の球果類(いわゆる針葉樹)が優占する森林が見られる。球果類の優占度は貧栄養土壌で高くなる。土壌栄養が中庸な立地では、球果類はまれな撹乱の際に更新し、長く林冠にとどまるという「長命な先駆種」という生活史を示すが、貧栄養立地では連続的に更新する。土壌栄養条件は被子植物広葉樹の成長に影響を与えることで、森林の光環境に影響を与え、最終的には球果類の優占度を決定していると考えられる。耐乾燥適応にも見える球果類の形質は、貧栄養条件への適応を反映していると考えられる。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2009年 -2012年 
    代表者 : 鈴木 英治, 宮本 旬子, 相場 慎一郎, 工藤 芳文, 中園 遼平, 亀井 愛美
     
    インドネシア西ジャワ州の保護区で主に移入種の問題を研究した。30 種余の移入種が出現したが、草本層ではClidemia hirta, Eupatoriumspp、高木層ではMaesopsis eminiiが多く増加が懸念された。場所によってキナノキとチークも拡大していた。自然林再生のため植栽されるSchima wallichiiは西ジャワの調査地間で遺伝的類似性が高く、植林が遺伝子組成を撹乱する可能性は低いと考えられた。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2009年 -2011年 
    代表者 : 甲山 隆司, 清野 達之, 久保 拓弥, 相場 慎一郎
     
    種多様性の高い東南アジア熱帯~暖温帯多雨林の樹木群集の共存機構を解明する目的で、森林追跡センサスに基づき、群集全体に共通する環境傾度依存性と種・個体特異的な動態(樹木サイズ依存的成長・死亡と新規加入)のパラメータを、ベイズモデルによって一斉に推定し、群集レベルの動態パラメータ間のトレード・オフと、それを反映した撹乱応答を解析した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2006年 -2010年 
    代表者 : 北山 兼弘, 岡田 直紀, 宮本 和樹, 相場 慎一郎, 久保田 康裕, 宮本 和樹, 相場 慎一郎, 久保田 康裕
     
    ボルネオ島の内陸性熱帯降雨林では、風化により土壌リンの量が低下し、かつ鉱物との反応によりわずかに残ったリンは難溶化していると思われる。ボルネオ島を広く踏査し、土壌リンの形態と濃度の調査から特にリン濃度の低い生態系を選び、そのようなリン制限が強くかかった熱帯降雨林が維持されるメカニズムについて、樹木のリン獲得や利用効率などの生理生態的適応、土壌微生物群集のリン循環における機能、の2つの側面から明らかにした。
  • 日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2006年 -2008年 
    代表者 : 相場 慎一郎
     
    本研究は、東アジアの常緑多雨林の純一次生産量と群集動態の長期変動を明らかにすることを目的とした。気候に季節性のない熱帯と季節性のある温帯で複数の標高点に調査地を設定して、さまざまな気温条件下にある多雨林の地理変異と経年変化を調査した。その結果、一次生産と群集動態の地理変異の大部分は、平均気温によって説明でき、熱帯と温帯の間の違いは不明瞭だった。数十年おきに起こる自然撹乱(熱帯ではかんばつ、温帯では巨大台風)も、森林に大きな影響を及ぼしていた。
  • 多雨林における純一次生産量の長期変動と地理変異に関する研究
    日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2003年 -2005年 
    代表者 : 相場 慎一郎
     
    本研究は、東アジアの多雨林の純一次生産量の長期変動を明らかにすることを第一の目的としている。植物は光合成によって二酸化炭素を固定して有機物を生産している。この総生産量から呼吸による損失量を差し引いた量が純一次生産量であり、地上部については、森林の現存量(幹と大枝)の増加分+葉や小枝の生産量として定義される。森林の現存量の増加分は樹木サイズの継続測定によって既存の経験式を用いて推定できる。葉や小枝の生産量を直接測定するのは困難であるが、原生的森林では生産量と死亡量がつり合うと仮定できるので、リター(落葉・落枝)量の測定によって推定できる。温帯と熱帯の調査地を比較することで、地理変異についても明らかにすることが第二の目的である。これまで、リター量については、キナバル山では共同研究により8年間におよぶデータが蓄積され、屋久島では申請者自身により6年間のデータが揃っている。リター量は年変動が大きく、平均値の推定と長期変動パターンの検出には長期間の調査が必要とされる。そこで、本年度も、屋久島で引き続きリタートラップによるリター量のモニタリングをおこなった。リタートラップにたまった落葉・落枝は申請者がおおよそ月1回のペースで回収し、葉・繁殖器官・枝・その他に分別して乾重を測定した。6年間調査した4か所の調査地の間には、同調した年変動が見られ、最大の年は最小の年の1.4-1.5倍の速度を示した。リターの内訳を見ると、繁殖器官の同調性が顕著であった。
  • 樹木多様性と熱帯降雨林生態系機能の関係の解明
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2001年 -2004年 
    代表者 : 北山 兼弘, 清野 達之, 里村 多香美, 長谷川 元洋, 鈴木 静男
     
    この研究の目的は、樹木多様性がどのように熱帯降雨林生態系の機能を支配しているのかを明らかにすることであり、地域レベルの種多様性が極端に異なるハワイ諸島とマレーシアの比較を行った。4年間に渡り、2地域に設けた土壌発達傾度に沿った複数の森林試験地において毎木調査を行い、木部の肥大成長量を算出した。また、全試験地に設置されたリタートラップからリター回収を2週間から1ヶ月毎に行い、回収したリターの器官別仕分け及び乾重測定を行い、リターの生産速度を明らかにした。ハワイ諸島については過去2年の、マレーシアについては過去4年のリター生産量が明らかになった。肥大成長量にリター生産量を加味して、森林の地上部純一次生産量を算定した。土壌栄養の減少に植物や従属生物がどのように適応しているのかを明らかにするため、特に共生菌根菌に焦点を絞り、マレーシアの代表的なサイトに於ける菌根バイオマスと菌体バイオマスの定量化を行った。各サイトから土壌を採取し、細根、菌根、土壌の3つに仕分けし、エルゴステロールを生化学マーカーとして菌体量の定量分析を行った。また、土壌微生物群集の群集解析を生化学的PLFA法を用いて行った。また、貧栄養に対する樹木の適応を組織解剖学的に明らかにするために、材の通導組織観察と葉の水ポテンシャル測定を行った。以上の結果、地域の種多様性が高いと、土壌栄養塩の減少に対して、組織的、生態生理的により栄養塩利用効率の高い(適応的)種への入れ替わりが起こり、熱帯降雨林の機能は維持されるとの新たな知見が得られた。一方、地域の種多様性が低いと、種の入れ替わりが起こらず、土壌栄養塩量を反映して森林の機能は大きく変化した。この結果により当初の作業仮説は指示された。
  • ボルネオ島熱帯雨林の多様性維持機構の研究
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2000年 -2003年 
    代表者 : 鈴木 英治, 安田 雅俊, 相場 慎一郎, 宮本 旬子, 山田 俊弘, 宮内 信文
     
    ボルネオ島全体の森林の多様性維持機構を研究するために、ブルネイのマリンブン自然遺産公園、マレーシアのサバ州のキナバル山、インドネシア西カリマンタン州ブツンクリフン,東カリマンタン州ベラウで、4年間に257日の現地調査を行った。ブルネイ4ha、カリマンタン6ha、キナバル1.5haの植生継続調査区を設定し、2733点の植物標本を採集した。ボルネオ島低地の大部分がフタバガキ科優占林であるが、その中にもさまざまな優占種を持つタイプがあることが判った。成長量を測ると、老齢林ではほとんど現存量の増加が見られないか、かえって枯死木のために減少し、若齢林では増加した。1haに出現する胸高直径4.8cm以上の樹木種数は約70種から約220種と、場所により異なったが、湿地林、河畔林、丘陵林と増加した。丘陵地では遷移の進行にともない多様性は増加するが、湿地林では減少する傾向があった。フタバガキ科以外にも多数の種があり、アオギリ科、センダン科などで同一属の数種が同じ森林で共存するための機構について樹形などから明らかにしようとした。ある種内に見られる遺伝的変異も多様性に関する一つの課題であり、ヤシ科のLicualaとCyrtostachys属について研究した。比較的狭い範囲で空間的な群落の多様性については、キナバル山において研究した。生活形としてみると、樹木だけではなくツル植物が多いことが熱帯の特徴の一つであり、ロタン類でその研究を進め多種が同一林の中に共存する機構について研究した。また、動物と植物の相互作用系も見逃せない問題であり、果実を散布する動物を中心としてブルネイで研究を行った。
  • 多雨林の樹木群集における多様性―生産性仮説の検証
    日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2001年 -2002年 
    代表者 : 相場 慎一郎
     
    本研究は、多雨林の樹木群集について、野外データに基づき、生産性が高いほど種多様性が高いという多様性-生産性仮説を検証することを第一の目的とした。地上部の生産性は、積み上げ法によって葉の生産と地上部現存量回転速度の和として推定する。樹木種多様性がすでに明らかになっていて、葉の生産と地上部現存量回転速度の長期継続調査を行っているアジアの2か所の山岳(屋久島・マレーシア)をおもな対象とした。 地上部の純一次生産速度を推定するために、鹿児島県屋久島(暖温帯多雨林)では、リタートラップをもちいてリター(落葉・落枝)を月1回回収し、葉・繁殖器官・枝・その他に分別して乾重を測定し、葉の生産速度を推定した。また、地上部の純一次生産の決定要因のひとつであるリターの分解速度を調査した。マレーシアのキナバル山(熱帯多雨林)では、調査区の樹木の幹直径を再測定し、地上部現存量回転速度を推定した。緯度傾度にそった解析のため、沖縄県西表島の亜熱帯多雨林でも調査区を設定した。以上のデータとこれまでに共同研究によって蓄積されたデータにもとづき、広域スケール(緯度・標高傾度)での多様性-生産性関係について検討した。 以上の成果のうち、マレーシアで得られた結果の一部は、共著論文として学術誌で発表した。おもな内容は、かんばつが森林の生産性に与えた影響(Aiba & Kitayama 2002)、調査区の樹木組成と種数-面積関係(Aiba, Kitayama & Repin 2002)、異なる地質条件における生産性の標高による変化(Kitayama & Aiba 2002)などである。
  • 林木種多様性の規定要因としての純生産速度と森林構造の評価
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 1998年 -1999年 
    代表者 : 相場 慎一郎


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