Anolis lizards are one of the most diverse vertebrate genera and are the classic example of adaptive radiation and convergent evolution. Anoles exhibit great morphological diversity produced by the ecological opportunity to exploit several arboreal niches. Anole radiation in the Caribbean islands is well studied, but the mainland radiation is less understood. We used a large morphological data set and a molecular phylogeny to describe the morphological diversification of anoles from northwestern South America, a region with the highest anole diversity on a mainland. We describe morphological diversity as summarized by ten morphotypes, defined mainly by body size, limb proportions, and subdigital lamellae. We show that some morphotypes are limited to forested lowlands and others to Andean highlands; by contrast, Anolis assemblages from tropical rainforests are comprised of the same four morphotypes. We demonstrate that morphological diversification followed a pattern of adaptive radiation across a landscape of adaptive peaks. Our results are consistent with the most recent hypothesis of convergence stated for Caribbean radiation, and demonstrate convergence between mainland morphotypes and Caribbean ecomorphs, which suggests that common processes are driving both radiations. © 2016 The Linnean Society of London
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.
The coexistence of several anoles in the same place is attributed to differential partitioning of resources. Although several mainland and island communities show a similar structure, differences in life-history traits, absence of niche complementarity, higher food supply and higher numbers of predators in mainland environments support the idea that predation, rather than competition, is a more important structuring force in mainland than in island anole communities. To analyse the pattern of ecological structure in mainland anole communities, we studied communities in three tropical rain forests of north-western South America to obtain data about the use of resources on three niche axes [spatial, thermal and morphological (as a proxy of diet)] for 17 species of anoles. We analysed the patterns of niche overlap for each axis and found that overlap on the dietary axis was less than the overlap on the other axes, indicating that species using similar spatial or thermal resources diverge strongly in their diet. In addition, we identified a niche complementarity among niche axes, suggesting that intraspecific competition is also an important process in those communities. Finally, this study revealed a similar ecological structure in different communities of mainland rain-forest anoles, which share seven ecomorphs, suggesting ecological adaptation and convergence in mainland anoles.
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