The transition from isolated patches to a metapopulation in the eastern collared lizard in response to prescribed fires

Abstract

Abstract. Habitat fragmentation often arises from human-induced alterations to the matrix that reduce or eliminate dispersal between habitat patches. Elimination of dispersal increases local extinction and decreases recolonization. These phenomena were observed in the eastern collared lizard (Crotaphytus collaris collaris), which lives in the mid-continental highland region of the Ozarks (Missouri, USA) on glades: habitats of exposed bedrock that form desert-like habitats imbedded in a woodland matrix. With the onset of woodland fire suppression, glade habitats degenerated and the woodland matrix was altered to create a strong barrier to dispersal. By 1980, lizard populations in the Ozarks were rapidly going extinct. In response to this decline, some glades were restored by clearing and burning. Starting in 1984, collared lizard populations were translocated onto these restored habitats. The translocated populations persisted but did not colonize nearby glades or disperse among one another. In 1994 prescribed woodland fires were initiated, which unleashed much dispersal and colonizing behavior. Dispersal was highly nonrandom by both intrinsic variables (age, gender) and extrinsic variables (overall demography, glade population sizes, glade areas, landscape features), resulting in different classes of lizards being dominant in creating demographic cohesiveness among glades, colonizing new glades on a mountain, and colonizing new mountain systems. A dramatic transition was documented from isolated fragments, to a nonequilibrium colonizing metapopulation, and finally to a stable metapopulation. This transition is characterized by the convergence of rates of extinction and recolonization and a major alteration of dispersal probabilities and pattern in going from the nonequilibrium to stable metapopulation states.

Dispersal responses override density effects on genetic diversity during post-disturbance succession

“…Habitat complexity inhibits movement within the perceptual range of ground-dwelling mammals [37], suggesting that succession could impede navigation. For reptiles, recently disturbed habitat is probably more thermally suitable for dispersal [4]. As an insectivore, N. stellatus likely benefited from increased invertebrate abundance [48] and may have had increased foraging success in recently burnt habitat [49].…”

Guidelines for Using Movement Science to Inform Biodiversity Policy

“…For example, forest fire suppression in the Missouri Ozarks, USA disrupted movements of collared lizards, reducing their genetic diversity and adaptive potential (Templeton et al 2001). Genetic studies revealed the effect of fire suppression on the movement of the lizards, leading to land management practices that re-established natural fire regimes and resulted in restoration of movement, metapopulation structure, and genetic diversity of the lizards (Templeton et al 2011). For species that have experienced severe habitat fragmentation, other strategies that may improve or enhance movements of individuals include the establishment of habitat corridors, gamete transfer, or translocations (Trakhtenbrot et al 2005;Tuberville et al 2005).…”

Physiological vagility and its relationship to dispersal and neutral genetic heterogeneity in vertebrates

“…The D max for amphibians are from a summary (166 articles, 90 species) compiled by Alex Smith and Green (Alex Smith and Green, 2005) and we estimated typical body masses of each species from field guides and the literature. The D max and typical body mass values for reptiles were taken from a variety of studies (Noble and Clausen, 1936;Hirth et al, 1969;Brown and Parker, 1976;Wiewandt, 1977;Werner, 1983;Larsen, 1987;Brown and Brooks, 1994;Madsen and Shine, 1996;Plummer, 1997;Pough et al, 1998;Hokit et al, 1999;Blouin-Demers and Weatherhead, 2002;Middendorf et al, 2005;Marshall et al, 2006;Keogh et al, 2007;Dubey et al, 2008;Rutherford and Gregory, 2003;Templeton et al, 2011;Warner and Shine, 2008;Welsh et al, 2010). The D max and typical body mass values for birds and mammals were taken from Sutherland et al (Sutherland et al, 2000).…”