Species with large intraspecific trait variability (ITV) have larger niche breadth than species with low ITV and thus are expected to be more abundant at the local scale. However, whether the positive ITV–abundance relationship holds in heterogeneous local environments remains uncertain. Using an individual-based trait dataset encompassing three leaf traits (leaf area, specific leaf area, and leaf dry mass content) of 20,248 individuals across 80 species in an environmentally heterogeneous subtropical forest in eastern China, ITV for each trait of each species was estimated by rarefaction. Resource-based niche breadth and marginality (the absolute distance between the mean resource states used by a species and the mean plot-wise resource states) were estimated simultaneously by the K–S method and the outlying mean index, respectively. Species with moderate ITV were often locally abundant, while species with large or small ITV were locally rare. This unimodal relationship between ITV and species abundance persisted when traits were analyzed separately and for all tree size classes. There was also a hump-backed relationship between niche breadth and marginality, and ITV was positively associated with niche breadth. The combined results suggest either a trade-off between the benefit from expanding niche breadth to adapt to multiple habitats and the disadvantage of reducing competitive ability, or a scarcity of favorable resources. Our results do not support the traditional thought that ITV positively correlates with species abundance in heterogeneous local environments. Instead, our study suggests that moderate—rather than large—intraspecific trait variability increases species abundance at local scales.
Bibliographical noteFunding Information:
This study was supported by the National Key Research and Development Program (2016YFC0503102 to G.C.S) and the National Natural Science Foundation of China (31870404 and 31470487 to G.S., and 31670438 and 31770467 to E.R.Y.).
We are grateful to Qun Song and Xiangcheng Mi for their constructive comments on the study. We also thank Min Guo, Qiang Zhong, Meng Kang, Yue Xu, Yilu Xu, Xiaodong Yang, Haixia Huang, Zhihao Zhang, Baowei Sun, Wenji Ma, Qingru Shi, Yantao Zhao, Liuli Zhou, Qingqing Zhang, Arshad Ali and many others for making this fantastic trait data available. Equipment used in this study was supported by ECNU Multifunctional Platform for Innovation (008).
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
- Commonness and rarity
- Niche breadth and marginality
- Trait-based ecology
- Unimodal relationship
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics