Gene flow and pathogen transmission among bobcats (Lynx rufus) in a fragmented urban landscape

Abstract

Urbanization can result in the fragmentation of once contiguous natural landscapes into a patchy habitat interspersed within a growing urban matrix. Animals living in fragmented landscapes often have reduced movement among habitat patches because of avoidance of intervening human development, which potentially leads to both reduced gene flow and pathogen transmission between patches. Mammalian carnivores with large home ranges, such as bobcats (Lynx rufus), may be particularly sensitive to habitat fragmentation. We performed genetic analyses on bobcats and their directly transmitted viral pathogen, feline immunodeficiency virus (FIV), to investigate the effects of urbanization on bobcat movement. We predicted that urban development, including major freeways, would limit bobcat movement and result in genetically structured host and pathogen populations. We analysed molecular markers from 106 bobcats and 19 FIV isolates from seropositive animals in urban southern California. Our findings indicate that reduced gene flow between two primary habitat patches has resulted in genetically distinct bobcat subpopulations separated by urban development including a major highway. However, the distribution of genetic diversity among FIV isolates determined through phylogenetic analyses indicates that pathogen genotypes are less spatially structured-exhibiting a more even distribution between habitat fragments. We conclude that the types of movement and contact sufficient for disease transmission occur with enough frequency to preclude structuring among the viral population, but that the bobcat population is structured owing to low levels of effective bobcat migration resulting in gene flow. We illustrate the utility in using multiple molecular markers that differentially detect movement and gene flow between subpopulations when assessing connectivity.

An agent‐based movement model to assess the impact of landscape fragmentation on disease transmission

“…Our findings regarding between-patch disease transmission are also consistent with FIV transmission among bobcats across the urban landscape of coastal southern California (Lee et al 2012). Although gene flow is restricted between two subpopulations of animals on either side of the Interstate 5 (I-5) freeway and associated urban development in Orange County, south of Los Angeles, FIV phylogenetic analyses document frequent viral transmissions among these two subpopulations.…”

“…For some species, urbanization can lead to reduced home range sizes and territories that overlap more when compared to rural locations (Riley 2006). The resultant increase in contact rates can lead to changes in disease transmission patterns in urbanizing landscapes (Bevins et al 2012, Lee et al 2012; increased contact between wild and domestic animals in urban areas can also introduce novel disease (Williams et al 1988, Laurenson et al 1998.…”

“…Bobcats are wideranging, fragmentation-sensitive carnivores; thus, they are excellent focal species for investigations of the impacts of urbanization in southern California and elsewhere (Laurenson et al 1998, Crooks 2002, Tigas et al 2002, Riley et al 2003, Ruell et al 2009). Intensive radio-and GPS telemetry studies have been conducted on the spatio-temporal movement patterns and habitat use of bobcats in urban areas near Los Angeles (Riley et al 2003, Riley et al 2010, Tracey et al 2013; these animals have also been screened for seroprevalence of multiple pathogens, including feline immunodeficiency virus (FIV; Franklin et al 2007, Bevins et al 2012, Lee et al 2012.…”

Characterization of Regionally Associated Feline Immunodeficiency Virus (FIV) in Bobcats (Lynx rufus)

“…Similarly, California isolates group into distinct Ventura County and Orange County clusters (Franklin et al, 2007). A recent analysis of southern California bobcat FIVs failed to reveal FIV monophylogeny on either side of a major freeway, even though host genetics were divided on this basis (Lee et al, 2012). FIV isolates infecting domestic cats represents a monophyletic clade that is highly divergent from isolates infecting pumas and bobcats, reiterating previous findings (Troyer et al, 2005;VandeWoude and Apetrei, 2006;Fig.…”

Population and genetic outcomes 20 years after reintroducing bobcats (Lynx rufus) to Cumberland Island, Georgia USA

“…2010; Lee et al. 2012; Reding et al. 2013), including individual populations from the southeastern U.S. ( H O  = 0.736, AR = 6.49) sampled by Reding et al.…”