Population Dynamics of the Andean Lizard Anolis heterodermus: Fast‐slow Demographic Strategies in Fragmented Scrubland Landscapes

Abstract

Habitat fragmentation and loss affect population stability and demographic processes, increasing the extinction risk of species. We studied Anolis heterodermus populations inhabiting large and small Andean scrubland patches in three fragmented landscapes in the Sabana de Bogotá (Colombia) to determine the effect of habitat fragmentation and loss on population dynamics. We used the capture-mark-recapture method and multistate models to estimate vital rates for each population. We estimated growth population rate and the most important processes that affect k by elasticity analysis of vital rates. We tested the effects of habitat fragmentation and loss on vital rates of lizard populations. All six isolated populations showed a positive or an equilibrium growth rate (k = 1), and the most important demographic process affecting k was the growth to first reproduction. Populations from landscapes with less scrubland natural cover showed higher stasis of young adults. Populations in highly fragmented landscapes showed highest juvenile survival and growth population rates. Independent of the landscape's habitat configuration and connectivity, populations from larger scrubland patches showed low adult survivorship, but high transition rates. Populations varied from a slow strategy with low growth and delayed maturation in smaller patches to a fast strategy with high growth and early maturation in large patches. This variation was congruent with the fast-slow continuum hypothesis and has serious implications for Andean lizard conservation and management strategies. We suggest that more stable lizard populations will be maintained if different management strategies are adopted according to patch area and habitat structure.Abstract in Spanish is available in the online version of this article.

Thermoregulation in the Andean lizard Anolis heterodermus (Squamata: Dactyloidae) at high elevation in the Eastern Cordillera of Colombia.

“…This also suggests that appropriate thermal microhabitats for A. heterodermus, consist of exposed perches at bordering vegetation and high stratum in the inner of each patch (1-2 m) (Moreno-Arias et al, 2010;Moreno-Arias & Urbina-Cardona, 2013).…”

“…This region has two wet seasons, from April to May and from October to November, with annual rainfalls around 850 mm (Cortés, 2003). The vegetation in this region is usually Andean scrubland, or Andean forests at the highest elevations (Cortés, 2003;Moreno-Arias & Urbina-Cardona, 2013).…”

“…1). We used a vertical thermal gradient because our study model is a tree lizard that commonly use vertical branches as perches (Moreno-Arias et al, 2010;Moreno-Arias & Urbina-Cardona, 2013). The thermal gradient (18-32°C) was created with 200 W bulbs in the upper extreme and cooling gels at the base.…”

“…Anolis heterodermus (Duméril, 1851) is part of a lineage previously known as Phenacosaurus that occupy high elevation environments in the Andes system (above 1,800 m AMSL; Dunn, 1944;Lazell, 1969;Rangel-Ch & Aguilar-P, 1995 (Dunn, 1944;Osorno-Mesa & OsornoMesa, 1946;Lazell, 1969;Miyata, 1983;Moreno-Arias & Urbina-Cardona, 2013;Vargas-Ramírez & MorenoArias, 2014). Despite its particularly interesting highland distribution, thermoregulatory strategy has not been studied in this species.…”

Genetic divergence and diversity in the Mona and Virgin Islands Boas, Chilabothrus monensis (Epicrates monensis) (Serpentes: Boidae), West Indian snakes of special conservation concern

“…58 Habitat fragmentation, whether due to natural or anthropogenic 59 factors, is among the most important causes of population and spe-60 cies declines and extinctions (Gibson et al, 2013;Wilcox and 61 Murphy, 1985). Fragmentation reduces the extent and connectivity 62 of suitable habitats, and thus can affect the sizes of local 63 populations, their demography, migration rates, and the geo-64 graphic distribution of demes (Groom et al, 2006;Moreno-Arias 65 and Urbina-Cardona, 2013;Pérez-Espona et al, 2012). 66 Consequently, a frequent outcome of habitat fragmentation is 67 reduced population size and increased isolation of conspecific 68 demes (Gottelli et al, 2013).…”