Environmental and spatial drivers of taxonomic, functional, and phylogenetic characteristics of bat communities in human-modified landscapes

Laura M Cisneros; Matthew E Fagan; Michael R Willig

doi:10.7717/peerj.2551

Environmental and spatial drivers of taxonomic, functional, and phylogenetic characteristics of bat communities in human-modified landscapes

PeerJ. 2016 Oct 13:4:e2551. doi: 10.7717/peerj.2551. eCollection 2016.

Authors

Laura M Cisneros¹, Matthew E Fagan², Michael R Willig³

Affiliations

¹ Department of Natural Resources and the Environment, University of Connecticut , Storrs , CT , United States.
² Department of Geography and Environmental Systems, University of Maryland Baltimore County , Baltimore , MD , United States.
³ Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, United States; Center for Environmental Science and Engineering, University of Connecticut, Storrs, CT, United States.

Abstract

Background: Assembly of species into communities following human disturbance (e.g., deforestation, fragmentation) may be governed by spatial (e.g., dispersal) or environmental (e.g., niche partitioning) mechanisms. Variation partitioning has been used to broadly disentangle spatial and environmental mechanisms, and approaches utilizing functional and phylogenetic characteristics of communities have been implemented to determine the relative importance of particular environmental (or niche-based) mechanisms. Nonetheless, few studies have integrated these quantitative approaches to comprehensively assess the relative importance of particular structuring processes.

Methods: We employed a novel variation partitioning approach to evaluate the relative importance of particular spatial and environmental drivers of taxonomic, functional, and phylogenetic aspects of bat communities in a human-modified landscape in Costa Rica. Specifically, we estimated the amount of variation in species composition (taxonomic structure) and in two aspects of functional and phylogenetic structure (i.e., composition and dispersion) along a forest loss and fragmentation gradient that are uniquely explained by landscape characteristics (i.e., environment) or space to assess the importance of competing mechanisms.

Results: The unique effects of space on taxonomic, functional and phylogenetic structure were consistently small. In contrast, landscape characteristics (i.e., environment) played an appreciable role in structuring bat communities. Spatially-structured landscape characteristics explained 84% of the variation in functional or phylogenetic dispersion, and the unique effects of landscape characteristics significantly explained 14% of the variation in species composition. Furthermore, variation in bat community structure was primarily due to differences in dispersion of species within functional or phylogenetic space along the gradient, rather than due to differences in functional or phylogenetic composition.

Discussion: Variation among bat communities was related to environmental mechanisms, especially niche-based (i.e., environmental) processes, rather than spatial mechanisms. High variation in functional or phylogenetic dispersion, as opposed to functional or phylogenetic composition, suggests that loss or gain of niche space is driving the progressive loss or gain of species with particular traits from communities along the human-modified gradient. Thus, environmental characteristics associated with landscape structure influence functional or phylogenetic aspects of bat communities by effectively altering the ways in which species partition niche space.

Keywords: Chiroptera; Environmental control; Forest loss; Fragmentation; Land conversion; Neotropics; Niche partitioning; Spatial mechanisms; Variation partitioning.

Grants and funding

This research was supported by a Student Research Scholarship from Bat Conservation International, a Research Fellowship from the Organization for Tropical Studies, two Grants-in-Aid Awards from the American Society of Mammalogists, and many intramural awards from the Center for Environmental Sciences and Engineering, Department of Ecology and Evolutionary Biology, and Center for Conservation and Biodiversity, all at the University of Connecticut (UCONN). Especially noteworthy, field work, data analysis, and manuscript preparation were supported by a Multicultural Fellowship from the Graduate School at UCONN. Furthermore, funding for the synthetic portion of this project was provided by a National Science Foundation grant to S. Andelman and J. Parrish entitled “The Dimensions of Biodiversity Distributed Graduate Seminar” (DEB-1050680). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.