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

Abstract

Habitat fragmentation threatens tropical rainforests, which can significantly hinder dispersal in species such as arboreal primates. For conservation actions to be effective there must be an understanding of how landscape structure and biological traits shape dispersal. We assessed the effects of landscape, sex and population management (reintroductions and translocations) on gene flow of Leontopithecus rosalia, an endangered arboreal primate living in highly fragmented forests of Brazil. We genotyped 201 individuals using 14 microsatellite loci to answer three questions: (1) How far does L. rosalia disperse? (2) Is dispersal sex-biased? (3) What are the relative contributions of population management, distance, roads and landscape resistance to genetic kinship? We hypothesized that (1) gene flow decrease between more distant sites; (2) males disperse more than females; and (3) management and land-cover resistance (i.e. landscape resistance) are the variables that most influence genetic kinship. We found positive spatial population-structure up to 8 km. The spatial structure was similar between females and males suggesting that they equally contribute to gene flow. Management and landscape resistance best explained genetic kinship, showing that different land-cover types affect the dispersal at different degrees of landscape permeability. We advocate that maintaining more permeable landscapes is essential to ensure dispersal and gene flow of arboreal mammals. Conservation measures in tropical rainforests must take into account not only the habitat amount, but also the degree at which each land useroads, urban areas, agriculture, pasture, isolated trees, and stepping stonesfacilitates or impedes the species dispersal.

Population Genetic Structure of an Endangered Endemic Primate (Leontopithecus chrysomelas) in a Highly Fragmented Atlantic Coastal Rain Forest

“…Thus, isolation by distance is a partial explanation for the variance in genetic distance given an incomplete sampling. Other factors such as physical barriers (e.g., open areas and roads) and behaviour may help explain additional variance in the differentiation among GHLTs, similar to observations for L. rosalia [Di Fiore and Valencia, 2014;Moraes et al, 2018].…”

“…These are important considerations for conservation, because the relative continuity of the landscape currently provided by the cabruca-dominated matrix may not be enough for the maintenance of gene flow, particularly for long distances such as observed between these patches (≥20 km). A landscape genetic study showed that L. rosalia may be able to disperse up to 8 km if the landscape is functionally connected [Moraes et al, 2018].…”

Unraveling the scales of effect of landscape structure on primate species richness and density of titi monkeys (Callicebus nigrifrons)

“…However, monkey density can also depend on interpatch animal movements across larger spatial scales, which may explain why titi monkey density was strongly related to both forest cover and forest patch density within larger landscape sizes. These landscape variables modulate landscape connectivity (Fahrig, 2003;Martensen et al, 2012), influencing the dispersal, gene flow and metapopulation dynamics among the remaining forest patches (Bowler & Benton, 2005;Fischer & Lindenmayer, 2007;Moraes et al, 2018).…”

“…Supporting this idea, primate species richness was strongly related to forest cover measured over larger spatial scales, probably because this variable is positively related to landscape connectivity (Fahrig, 2013), and thus, it can shape ecological processes such as migrations (Bowler & Benton, 2005;Dunning et al, 1992;Wiens, Stenseth, Van Horne, & Ims, 1993). Nevertheless, there is an increasing number of studies demonstrating that the number of animal species in fragmented landscapes also depends on local patterns and processes, such as inter-patch animal movements, resource availability, inter-and intra-specific interactions and diseases (Ewers & Didham, 2006;Fischer & Lindenmayer, 2007;Martensen, Ribeiro, Banks-Leite, Prado, & Metzger, 2012;Moraes et al, 2018). For example, as habitat availability increases in the vicinity of a given focal patch, species richness in the patch can be affected by individuals, species and resources present in the surrounding habitat (Fahrig, 2013).…”

“…We compared the predictive power between each response variable and each landscape variable across 10 different-sized spatial extents (0.2-28.3 km 2 ) to identify the landscape size within which primate-landscape relationships were best predicted. Forest specialist species-such as most Neotropical primates-are particularly vulnerable to local and landscape disturbances (Arroyo-Rodríguez & Mandujano, 2009;Chapman & Peres, 2001;Estrada et al, 2017;Marsh et al, 2013;Moraes et al, 2018). At the local level, for instance, the occurrence of primates may be influenced by the availability of food resources (e.g., Alouatta palliata mexicana; Arroyo-Rodríguez, Mandujano, Benítez-Malvido, & Cuende-Fantón, 2007).…”