Does scale matter? The influence of three-level spatial scales on forest bird occurrence in a tropical landscape

Abstract

Consequences of habitat fragmentation for species occurrence are amongst the most important issues in landscape and conservation ecology. Empirical and theoretical studies have demonstrated that the total amount of habitat, patch size and connectivity have nonlinear effects on species survival on multiple spatial and temporal scales. Therefore, population models need to incorporate multiple scales, which can be extremely valuable to prioritizing conservation efforts in these changing landscapes. We tested how the amount and configuration of habitat affect understory bird species occurrence using fine to broad-scale habitat features. We used playback to sample birds in 13 Atlantic Forest fragments in Southeast Brazil. Microhabitat, local and regional landscape variables were tested against bird occurrence. Our results demonstrate that different bird species respond to different habitat scales. Sclerurus scansor, Xiphorhynchus fuscus, Automolus leucophthalmus, Drymophila ochropyga, Mackenziaena leachii, and Chiroxiphia caudata were most influenced by tree height and diameter (microhabitat characteristics), S. scansor, F. serrana and Pyriglena leucoptera were most influenced by forest cover and red-edge reflectance(local-scale metrics) and S. scansor, X. fuscus, D. ochropyga, P. leucoptera, F. serrana and M. leachii had area, core area and functional connectivity index (landscape features) as stronger predictors of species occurrence. Small forest fragments acted as corridors and increased overall connectivity of the entire community. The most effective means of maintaining long-term population connectivity of understory birds involves retaining both large and small areas, including forests with different micro-habitat characteristics. No management approach based on a single-scale would benefit all species. Implementing multiscale conservation strategies are necessary for maintaining long-term viability of forest birds on tropical landscapes.

Local species turnover increases regional bird diversity in mangroves

“…Thus bird species composition is not responding to vegetation zonation, which also has only marginal responses related to the frequency of flooding or soil salinity (Sobrinho et al 1969;Lugo & Snedaker 1974;Souza et al 1994). This pattern contrasts with bird metacommunity studies in other ecosystems (Meynard & Quinn 2008;Uezu & Metzger 2011;Gianuca et al 2013;Bonthoux & Balent 2015;Casas et al 2016;Gonc ßalves et al 2017;Bhakti et al 2018) in which either environmental gradients, habitat structure, or both, were important drivers of the composition of the local bird metacommunity and supported a process of species sorting (Leibold et al 2004). We thus believe that internal dynamics, based on competition-colonisation trade-offs play a key role in the structuring of mangrove bird communities, suggesting a process of patch dynamics (Leibold et al 2004;Chase et al 2005).…”

“…We thus believe that internal dynamics, based on competition-colonisation trade-offs play a key role in the structuring of mangrove bird communities, suggesting a process of patch dynamics (Leibold et al 2004;Chase et al 2005). Nevertheless, landscape factors, especially patch size, do appear to have a small, but relevant influence on the composition of the mangrove bird community, with larger mangroves having more species than smaller patches, which is a pattern often reported (Uezu & Metzger 2011;Fahrig 2013;Bhakti et al 2018).…”

“…2017; Bhakti et al . 2018) in which either environmental gradients, habitat structure, or both, were important drivers of the composition of the local bird metacommunity and supported a process of species sorting (Leibold et al . 2004).…”

The scale of effect depends on operational definition of forest cover—evidence from terrestrial mammals of the Brazilian savanna

“…In the Cerrado, we recommend that initiatives examining spatial arrangement of landscape attributes of forest cover in relation to populations in terrestrial mammals (from small to large body sized species) should consider buffer sizes from 500 to 2000 m. However, the puzzle is far more complicated with questions regarding communities. No management approach based on a single scale would benefit all species (Crouzeilles and Curran 2016;Bhakti et al 2018). It might be important to analyse a large range of species and set targets for each one using specific scales.…”

Analyzing the effect of silvicultural management on the trade-off between stand structural heterogeneity and productivity over time

“…The extent of structural heterogeneity in forests moreover depends on the spatial scale at which it is measured (Leimgruber et al 2002;Stein et al 2014;Bhakti et al 2018). Depending on the purpose of a forest, a provision of certain stand characteristics might be sufficient or particularly important at a larger spatial scale (Saab 1999;van der Plas et al 2016).…”