Nestedness of desert bat assemblages: species composition patterns in insular and terrestrial landscapes

Abstract

Nested patterns of community composition exist when species at depauperate sites are subsets of those occurring at sites with more species. Nested subset analysis provides a framework for analyzing species occurrences to determine non-random patterns in community composition and potentially identify mechanisms that may shape faunal assemblages. We examined nested subset structure of desert bat assemblages on 20 islands in the southern Gulf of California and at 27 sites along the Baja California peninsula coast, the presumable source pool for the insular faunas. Nested structure was analyzed using a conservative null model that accounts for expected variation in species richness and species incidence across sites (fixed row and column totals). Associations of nestedness and island traits, such as size and isolation, as well as species traits related to mobility, were assessed to determine the potential role of differential extinction and immigration abilities as mechanisms of nestedness. Bat faunas were significantly nested in both the insular and terrestrial landscape and island size was significantly correlated with nested structure, such that species on smaller islands tended to be subsets of species on larger islands, suggesting that differential extinction vulnerabilities may be important in shaping insular bat faunas. The role of species mobility and immigration abilities is less clearly associated with nestedness in this system. Nestedness in the terrestrial landscape is likely due to stochastic processes related to random placement of individuals and this may also influence nested patterns on islands, but additional data on abundances will be necessary to distinguish among these potential mechanisms.

Phylogenetic community structure of North American desert bats: influence of environment at multiple spatial and taxonomic scales

“…). Bat communities along the coast of Baja California also exhibit significant structure (Frick, Hayes & Heady ). Studies of communities in other areas have found evidence that bats can partition similar resources by making use of slightly different foraging strategies based on echolocation call frequency, wing shape, diet, habitat preferences and temporal activity (e.g.…”

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

“…Furthermore, species life‐history traits may also be useful for assessing the contribution of differential abilities of species to nestedness (Worthen et al. , 1996; Meyer & Kalko, 2008; Frick et al. , 2009), although this approach has received less attention.…”

“…For example, if dispersal ability is a strong determinant of nested patterns (Cook & Quinn, 1995; Kadmon, 1995; Loo et al. , 2002), then ecomorphological characters reflecting relative mobility of species may order species occurrence patterns (Frick et al. , 2009).…”

Facultative Nectar-Feeding Behavior in a Gleaning Insectivorous Bat (Antrozous pallidus)

“…Presence of cactus pollen on pallid bats.-Mist-net sampling of bats was conducted at 28 locations on the Baja California peninsula and on islands in the Gulf of California as part of this and previous research from 2005 to 2008 (Frick et al 2008a(Frick et al , 2008bFig. 1).…”