Patch Size, Functional Isolation, Visibility and Matrix Permeability Influences Neotropical Primate Occurrence within Highly Fragmented Landscapes

Abstract

Forest fragmentation and habitat loss are among the major current extinction causes. Remaining fragments are mostly small, isolated and showing poor quality. Being primarily arboreal, Neotropical primates are generally sensitive to fragmentation effects. Furthermore, primates are involved in complex ecological process. Thus, landscape changes that negatively interfere with primate population dynamic affect the structure, composition, and ultimately the viability of the whole community. We evaluated if fragment size, isolation and visibility and matrix permeability are important for explaining the occurrence of three Neotropical primate species. Employing playback, we verified the presence of Callicebus nigrifrons, Callithrix aurita and Sapajus nigritus at 45 forest fragments around the municipality of Alfenas, Brazil. We classified the landscape and evaluated the metrics through predictive models of occurrence. We selected the best models through Akaike Selection Criterion. Aiming at validating our results, we applied the plausible models to another region (20 fragments at the neighboring municipality of Poço Fundo, Brazil). Twelve models were plausible, and three were validated, two for Sapajus nigritus (Area and Area+Visibility) and one for Callicebus nigrifrons (Area+Matrix). Our results reinforce the contribution of fragment size to maintain biodiversity within highly degraded habitats. At the same time, they stress the importance of including novel, biologically relevant metrics in landscape studies, such as visibility and matrix permeability, which can provide invaluable help for similar studies in the future and on conservation practices in the long run.

Landscape resistance influences effective dispersal of endangered golden lion tamarins within the Atlantic Forest

“…Teixeira et al, 2013) and the structure of inter-habitat matrix (e.g. Pozo-Montuy et al, 2011;Silva et al, 2015).…”

Local and landscape influences on the habitat occupancy of the endangered maned sloth Bradypus torquatus within fragmented landscapes

“…Maps of the Matrix Influence (MI) address the influence of different land use classes on the species distribution or occurrence (see a similar approach for primates in Silva et al, 2015). For this, we prepared and analyzed the MI maps through two strategies: (a) Matrix Influence based on the Access to Resources (MIAR) and (b) Matrix Influence based on the Mobility (MIM) of the species; both strategies considered the weights for each class of land use and occupation.…”

“…This new conformation results in non-habitats for a variety of species and can disrupt several ecological and demographic processes (Ricketts, 2001;Laurance and Vasconcelos, 2009;Pütz et al, 2011). For instance, small and isolated fragments may not constitute good habitat for the many species that are negatively affected mainly by the reduced habitat availability and the edge effect (Araújo et al, 2015;Silva et al, 2015). However, small patches may represent available habitats for those species with small home range (Arroyo- Rodríguez and Dias, 2010).…”

Local vs landscape drivers of primate occupancy in a Brazilian fragmented region

“…That 250m distance was chosen for it is close to the critical distance a human listener can discriminate a titi monkey vocalization (Robinson 1981;Dacier et al 2011). Other playbackbased primate surveys in fragmented landscapes also have used similar approaches (da Silva et al 2015). That procedure enabled sampling effort to be proportional to patch size.…”