BIODIVERSITY RESEARCH: Nestedness for different reasons: the distributions of birds, lizards and small mammals on islands of an inundated lake

Abstract

Aim We examined whether the community compositions of birds, lizards and small mammals were nested in a fragmented landscape in the Thousand Island Lake, China. We also assessed whether the mechanisms influencing nestedness differed among these taxonomic groups. Location Thousand Island Lake, China. Methods Presence/absence matrices were compiled for birds (42 islands) and lizards (42 islands) using line‐transect methods, and for small mammals (14 islands) using live‐trapping methods from 2006 to 2009. Nestedness was analysed using BINMATNEST, and statistical significance was assessed using the conservative null model 3. We used Spearman rank correlations and partial Spearman rank correlations to examine associations of nestedness and habitat variables (area, isolation, habitat diversity and plant richness) as well as life‐history traits (body size, habitat specificity, geographical range size and area requirement) related to species extinction and immigration tendencies. Results The community compositions of birds, lizards and small mammals were all significantly nested, but the causal factors underlying nestedness differed among taxonomic groups. For birds, island area, habitat specificity and area requirement were significantly correlated with nestedness after controlling for other independent variables. For lizards, habitat heterogeneity was the single best correlate of nestedness. For small mammals, island area, habitat heterogeneity and habitat specificity were significantly correlated with nestedness. The nested patterns of birds, lizards and small mammals were not attributable to passive sampling or selective colonization. Main conclusions The processes influencing nested patterns differed among taxonomic groups. Nestedness of bird assemblages was driven by selective extinction, and lizard assemblage was caused by habitat nestedness, while nestedness of small mammals resulted from both selective extinction and habitat nestedness. Therefore, we should take taxonomic differences into account when analysing nestedness to develop conservation guidelines and refrain from using single taxa as surrogates for others.

Ecological impacts of tropical forest fragmentation: how consistent are patterns in species richness and nestedness?

“…We chose this method over commonly used alternatives (e.g. the nestedness temperature calculator; [58]) because BINMATNEST is a more robust test [29]. As recommended by the authors [22], we used null model 3 to examine whether the assemblages of birds in the different studies were significantly nested.…”

“…wing length [35,36]) may be more important in ordering species. However, this approach has received little attention [29].…”

“…Habitat nestedness considers the nestedness of species assemblages to arise as a result of their reliance on habitats that have a nested distribution [30]. Differences in the processes generating nestedness have important implications for conservation and can be used to direct management efforts [29], but are only poorly understood.…”

“…Nestedness of species assemblages in forest fragments may arise as a result of four different processes (passive sampling, selective extinction, selective colonization and habitat nestedness [29]), which predict different patterns of nestedness among species and among fragments. Passive sampling could generate nestedness as a consequence of the fact that rare species are less likely to be sampled in a given area than common species, leading to the prediction that species with low average abundance will be a nested subset of those with high average abundance.…”

Patrones de distribución geográfica de la riqueza de especies de roedores de la tribu Oryzomyini (Rodentia: Sigmodontinae) en Sudamérica: Evaluando la importancia de los procesos de colonización y extinción

“…2). E s t o s r e s u l t a d o s c o n c u e r d a n c o n diversos estudios que revelan sistemas significativamente anidados (e.g., Atmar & Patterson 1993, Peintinger et al 2003, Wang et al 2010. Sin embargo, ha existido mucho debate sobre los mecanismos subyacentes al anidamiento, como por ejemplo, si la extinción o la colonización selectiva es la causante de los patrones anidados (Ulrich et al 2009).…”