The effect of environmental heterogeneity on species richness depends on community position along the environmental gradient.
Environmental heterogeneity is among the most important factors governing community structure. Besides the widespread evidence supporting positive relationships between richness and environmental heterogeneity, negative and unimodal relationships have also been reported. However, few studies have attempted to test the role of the heterogeneity on species richness after removing the confounding effect of resource availability or environmental severity. Here we constructed an individual-based spatially explicit model incorporating a long-recognized tradeoff between competitive ability and stress-tolerance ability of species. We explored the impact of the level of resource availability (i.e. the position of the community along a gradient of environmental severity) on the heterogeneity-diversity relationship (HDR). The results indicate that the shape of HDR depends on the community position along the environmental gradient: at either end of the gradient of environmental severity, a positive HDR occurred, whereas at the intermediate levels of the gradient, a unimodal HDR emerged. Our exploration demonstrates that resource availability/environmental severity should be considered as a potential factor influencing the shape of the HDR. Our theoretical predictions represent hypotheses in need of further empirical study.
State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Zhiyong
Z
Yang
State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Xueqi
X
Liu
State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Mohua
M
Zhou
State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Dexiecuo
D
Ai
State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Gang
G
Wang
Ministry of Education Key Laboratory of Western China's Environmental Systems, Research School of Arid Environment and Climate Change, Lanzhou University, Lanzhou, 730000, China.
Youshi
Y
Wang
State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.|SYSU-Alberta Joint Lab for Biodiversity Conservation, State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
Chengjin
C
Chu
Department of Biology/Environmental Studies Program, Saint Mary's University, Halifax, Nova Scotia, Canada B3H3C3.
Jeremy T
JT
Lundholm
D044822:Biodiversity; D017753:Ecosystem; D004777:Environment; D012111:Residence Characteristics; D012919:Social Behavior; D013312:Stress, Physiological / Q000502:physiology