Wednesday, August 9, 2017: 11:10 AM
D139, Oregon Convention Center
Joseph A. LaManna1, Scott A. Mangan2, Alfonso Alonso3, Norman A. Bourg4, Warren Y. Brockelman5, Sarayudh Bunyavejchewin6, Li-Wan Chang7, Jyh-Min Chiang8, George B. Chuyong9, Keith Clay10, Richard Condit11, Susan Cordell12, Stuart J. Davies13, Tucker Furniss14, Christian P. Giardina12, I.A.U. Nimal Gunatilleke15, C. V. Savi Gunatilleke16, Fangliang He17, Robert W. Howe18, Stephen P. Hubbell11, Chang-Fu Hsieh19, Faith Inman-Narahari20, David Janík21, Daniel J Johnson22, David Kenfack23, Lisa Korte24, Kamil Král21, Andrew J. Larson25, James A. Lutz26, Sean M McMahon27, William J. McShea28, Hervé Memiaghe29, Anuttara Nathalang5, Vojtech Novotny30, Perry Ong31, David A. Orwig32, Rebecca Ostertag33, Geoffrey G. Parker34, Richard P. Phillips35, Lawren Sack36, I-Fang Sun37, J. Sebastian Tello38, Duncan W Thomas39, Benjamin L. Turner40, Dilys Vela Diaz2, Tomáš Vrška21, George Weiblen41, Amy T. Wolf42, Sandra Yap43 and Jonathan A. Myers1, (1)Washington University in St. Louis, St. Louis, MO, (2)Biology, Washington University in St. Louis, St. Louis, MO, (3)Center for Conservation Education and Sustainability, Smithsonian Conservation Biology Institute, Washington, DC, (4)Conservation and Research Center, Smithsonian Institution - National Zoological Park, Front Royal, VA, (5)BIOTEC Central Research Unit, Pathum Thani, Thailand, (6)Research Office, Department of National Parks, Bangkok, Thailand, (7)Taiwan Forestry Research Institute, Yilan, Taiwan, (8)Department of Life Science, Tunghai University, Taichung, Taiwan, (9)Plant and Animal Sciences, University of Buea, Buea, Cameroon, (10)Department of Biology, Indiana University, Bloomington, IN, (11)Smithsonian Tropical Research Institute, Panamá City, Panama, (12)Institute of Pacific Islands Forestry, USDA Forest Service, Hilo, HI, (13)Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Washington, DC, (14)Wildland Resources Department, Utah State University, (15)Department of Botany, University of Peradeniya, Faculty of Science, Peradeniya, Sri Lanka, (16)Department of Botany, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka, (17)School of Life Sciences, Sun Yat-sen University, Guangzhou, China, (18)Cofrin Center for Biodiversity, University of Wisconsin-Green Bay, Green Bay, WI, (19)Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, Taiwan, (20)Institute of Pacific Islands Forestry, USDA Forest Service, (21)Department of Forest Ecology, Silva Tarouca Research Institute, (22)Los Alamos National Lab, (23)Center for Tropical Forest Science & Smithsonian Global Earth Observatory, Washington, DC, (24)Center for Conservation Education and Sustainability, Smithsonian Conservation Biology Institute, (25)College of Forestry and Conservation, University of Montana, Missoula, MT, (26)Department of Wildland Resources, Utah State University, Logan, UT, (27)Smithsonian Environmental Research Center, Smithsonian Institution, Edgewater, MD, (28)Conservation Ecology Center, Smithsonian Conservation Biology Institute at the National Zoological Park, Front Royal, VA, (29)Institut de Recherche en Ecologie Tropicale, (30)Department of Zoology, University of South Bohemia, Ceske Budejovice, Czech Republic, (31)Institute of Biology, University of the Philippines - Diliman, Quezon City, Philippines, (32)Harvard Forest, Harvard University, Petersham, MA, (33)Department of Biology, University of Hawaii at Hilo, Hilo, HI, (34)Smithsonian Environmental Research Center, Edgewater, MD, (35)Biology, Indiana University, Bloomington, IN, (36)Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, (37)Department of Natural Resources and Environmental Studies, National Dong Hwa University, Hualien, Taiwan, (38)Center for Conservation and Sustainable Development, Missouri Botanical Garden, St. Louis, MO, (39)School of Biological Sciences, Washington State University, Vancouver, WA, (40)Smithsonian Tropical Research Institute, Ancon, Panama, (41)Department of Plant Biology, University of Minnesota, St. Paul, MN, (42)Natural and Applied Sciences, University of Wisconsin-Green Bay, Green Bay, WI, (43)Institute of Arts and Sciences, Far Eastern University Manila
Background/Question/Methods One of the most ubiquitous patterns in ecology is the systematic increase in species richness from temperate to tropical latitudes. Theory predicts that conspecific negative density dependence (CNDD) resulting from specialized host-enemy interactions maintains higher biodiversity in the tropics. However, this remains untested at the global scale. Moreover, different strengths of CNDD across common and rare species may determine the ways in which CNDD maintains diversity. We measured CNDD as the degree to which conspecific adults suppress recruitment of saplings relative to negative effects from heterospecific densities. We measured CNDD across species as well as the mean strength of CNDD in each of 24 stem-mapped forest plots that are part of the Smithsonian Center for Tropical Forest Science Forest Global Earth Observatory (CTFS-ForestGEO) network.
Results/Conclusions
We show that global patterns in tree-species diversity reflect not only stronger CNDD at tropical latitudes, but also latitudinal shifts in the relationship between CNDD and species-relative abundance. Across 24 forest plots worldwide, species richness and diversity increased with the strength of CNDD. Moreover, CNDD was stronger for rare species at tropical latitudes but stronger for common species at temperate latitudes. These results indicate fundamental differences in the nature of local-scale biotic interactions that maintain diversity in tropical and temperate forests and contribute to the latitudinal-diversity gradient.
