• 1 Department of Integrative Biology, University of Wisconsin, Madison, Wisconsin, USA
  • 2 Department of Natural Resources and Environmental Studies, National Dong Hwa University, Hualien, Taiwan
  • 3 Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
  • 4 Forest Research Institute Malaysia, Kuala Lumpur, Malaysia
  • 5 Department of Plant Biology, Southern Illinois University, Carbondale, Illinois, USA
  • 6 Institute of CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
  • 7 Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
  • 8 Department of Life Science, Tunghai University, Taichung, Taiwan
  • 9 Biology Department, Lewis & Clark College, Portland, Oregon, USA
  • 10 Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan
  • 11 Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
  • 12 Laboratorio de Ecología de Plantas, Herbario QCA, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
  • 13 Department of Environmental Science, University of Puerto Rico at Rio Piedras, San Juan, Puerto Rico
Nature, 2017 10 05;550(7674):105-108.
PMID: 28953870 DOI: 10.1038/nature24038


The tropical forests of Borneo and Amazonia may each contain more tree species diversity in half a square kilometre than do all the temperate forests of Europe, North America, and Asia combined. Biologists have long been fascinated by this disparity, using it to investigate potential drivers of biodiversity. Latitudinal variation in many of these drivers is expected to create geographic differences in ecological and evolutionary processes, and evidence increasingly shows that tropical ecosystems have higher rates of diversification, clade origination, and clade dispersal. However, there is currently no evidence to link gradients in ecological processes within communities at a local scale directly to the geographic gradient in biodiversity. Here, we show geographic variation in the storage effect, an ecological mechanism that reduces the potential for competitive exclusion more strongly in the tropics than it does in temperate and boreal zones, decreasing the ratio of interspecific-to-intraspecific competition by 0.25% for each degree of latitude that an ecosystem is located closer to the Equator. Additionally, we find evidence that latitudinal variation in climate underpins these differences; longer growing seasons in the tropics reduce constraints on the seasonal timing of reproduction, permitting lower recruitment synchrony between species and thereby enhancing niche partitioning through the storage effect. Our results demonstrate that the strength of the storage effect, and therefore its impact on diversity within communities, varies latitudinally in association with climate. This finding highlights the importance of biotic interactions in shaping geographic diversity patterns, and emphasizes the need to understand the mechanisms underpinning ecological processes in greater detail than has previously been appreciated.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.