The strength of density‐dependent mortality is contingent on climate and seedling size. (27th June 2018)

• Record Type: Journal Article
• Authors: Song, Xiaoyang; Johnson, Daniel J.; Cao, Min; Umaña, Maria Natalia; Deng, Xiaobao; Yang, Xiaofei; Zhang, Wenfu; Yang, Jie
• Editors: Collins, Beverly
• Is Part Of: Journal of vegetation science. Volume 29:Number 4(2018:Jul.)
• Page Start: 662
• Page End: 670
• Publication Date: 2018-06-27
• Subjects: competition -- density dependence -- Janzen‐Connell hypothesis -- mixed models -- neighbour effect -- precipitation -- seedling -- temperature; Plant ecology -- Periodicals; Plant communities -- Periodicals; Plant populations -- Periodicals; 581.7
• DOI: 10.1111/jvs.12645
• Languages: English
• ISSNs: 1100-9233

Abstract

Abstract: Questions: Density‐dependent processes may promote species diversity in plant communities. Here, we tested whether seedling survival was density‐dependent and varied by seedling size, species and climatic factors. Location: Tropical rain forest, Xishuangbanna, southwest China. Methods: Generalized linear mixed‐effects models were used to examine seedling survival (232 tree species) across 9 years of seedling census data from a 20‐ha tropical forest dynamics plot. Our predictor variables were conspecific and heterospecific neighbour density, size of the seedling and annual variation in climatic factors. Results: We found significant negative effects of conspecific tree density, but positive effects of heterospecific seedling density on the survival of tree seedlings in this plot. In general, conspecific negative density dependence (CNDD) was observed most frequently for large size classes of seedlings (≥20‐cm high), while heterospecific positive density dependence (HPDD) was similar at all size classes. CNDD for large seedlings was stronger during warm years, and HPDD for large seedlings was stronger during dry years. Conclusions: Our study suggests that the strength of density dependence varied through time, and this strength was influenced by water availability and temperature. Our results highlight the potential for changes in species composition and species co‐existence that could result from increasing temperature‐strengthening CNDD effects and decreasing precipitation strengthening HPDD effects. Abstract : In this study, we tested the correlation between the strength of density dependence and climatic conditions across 9 years of censuses. We found the strength of density dependence fluctuates and is significantly correlated with temperature and precipitation. Our study highlights the alteration of the strength of density dependence with climate change which will alter community composition in tropical forest.