Gene flow in a direct-developing, leaf litter frog between isolated mountains in the Taita Hills, Kenya

Abstract

Amphibians are in decline worldwide, and high altitude tropical areas appear to be the worst affected. This is in stark contrast with current information we have on gene flow in amphibian populations which focus on temperate pond breeding species. Using AFLP markers, we show that a small, directdeveloping, leaf litter frog from the Taita Hills in south-west Kenya (Schoutedenella xenodactyloides) has extended populations covering large areas (>3.5 km) of fragmented, forest habitat, uncharacteristic of typical amphibian models. Further, we demonstrate high levels of gene flow (F ST < 0.065) through unsuitable dry savannah habitat which might otherwise be considered a barrier to dispersal. Landscape genetic analysis demonstrates a strong link between hydrologic features, and further highlights links between sites through specific catchments. We propose a model of passive-active dispersal for the Dwarf Squeaker, S. xenodactyloides, which features passive downhill and active uphill movements over large areas, contrasting with limited cross slope movements. Our study highlights the importance of the diverse reproductive strategies of the Amphibia when considering dispersal and gene flow, and hence conservation management.

Genetic structure among coastal tailed frog populations at Mount St. Helens is moderated by post‐disturbance management

“…Tailed frogs, and amphibians in general, are not known to exhibit simple isolation by Euclidean distance (Funk et al 2005, Spear et al 2005, Giordano et al 2007, Measey et al 2007; thus, there are perhaps additional unsampled landscape variables that better explain genetic structure in the tephra-fall forest. The blast area model included variables similar to the global model, but with roughly half of the r 2 support.…”

Gene-flow in the clouds: landscape genetics of a viviparous, montane grassland toad in the tropics

“…In general, it is assumed that amphibians are highly philopatric and poor dispersers (Smith and Green 2005), and that life-history traits, as for example body size and reproductive mode, are important for population structure (Measey et al 2007;Wollenberg-Valero 2015). We found the global Nimba toad populations to be structured in three distinct subpopulations.…”

“…Hence, the distance among regions, the small body size and the harsh conditions during the dry season may result in the highly significant population differentiation. Reproductive mode was shown to influence population structure in amphibians (Measey et al 2007;Fouquet et al 2015;Mims et al 2015;Paz et al 2015). Species showing reproduction independent of open water, e.g.…”

“…Species showing reproduction independent of open water, e.g. due to direct development (Measey et al 2007) may show low levels of population differentiation. Nimba toads are viviparous and lack any aquatic larval stage.…”

“…Additionally, the interaction between landscape and gene-flow was shown to be species-specific and may differ among ecologically similar (Richardson 2012) and closely related species Storfer 2008, 2010). Nevertheless, four characteristics have been identified to have an important but sometimes opposing influence on connectivity of amphibian populations: life history traits (Measey et al 2007;Savage et al 2010;Nowakowski et al 2015), recent (anthropogenic) land use history (Richardson 2012;Cornetti et al 2016), habitat type Storfer 2008, 2010;Nowakowski et al 2015), and topography (Funk et al 2005;Spear et al 2005). Hence, until sufficiently abundant data on population structure, population size, and connectivity is available these characteristics need to be analysed for every focal species to develop sound conservation plans.…”