Abstract:

Aims Negative density dependence plays an important role in maintaining forest biodiversity. Ecologists found this mechanism operates not only between conspecifics but also between closely related heterospecifics. Our objective was to determine whether phylogenetic diversity affects seedling mortality at different scales.
Methods We used net relatedness index (NRI) and nearest taxon index (NTI) to represent phylogenetic diversity and employed logistic regression modeling. We analyzed the relationship between seedling mortality and phylogenetic diversity using the seedling dynamic data from six seedling censuses of 507 seedling plots at Gutianshan Nature Reserve during May 2006 and November 2007.
Important findings We found that higher density of conspecifics resulted in higher seedling mortality, and phylogenetic diversity was responsible for seedling mortality when seedling density was high (>3.46 individuals·m^-2).

Key words: negative density dependence, phylogenetic diversity, net relatedness index, logistic regression, seedling mortality