Effects of Habitat Disturbance on Lizard Functional Diversity in a Tropical Dry Forest of the Pacific Coast of Mexico

Abstract

Tropical dry forests are complex and diverse ecosystems threatened by multiple anthropogenic factors, such as habitat disturbance caused by land use change. We assessed species and functional diversity of lizard communities in areas with different levels of tropical dry forest disturbance in the Chamela region, Mexico. Functional richness, functional evenness, and functional dispersion were assessed considering six lizard functional traits. We recorded 415 lizards of 15 species. Species richness, species diversity, functional richness, functional dispersion, and the number of functional groups are lower in disturbed sites than in undisturbed tropical dry forest sites. On the contrary, abundance and functional evenness were higher in strongly disturbed sites. We suggest that lizard functional diversity should be studied further in order to secure the integrity of herpetofaunal communities and ecosystem processes.

Herpetofauna inside and outside from a natural protected area: the case of Reserva Estatal de la Biósfera Sierra San Juan, Nayarit, Mexico

“…These studies found a decrease in species richness and diversity to transformed environments. These results show a remarkable difference in species richness and composition of communities among areas (Gardner et al 2007, Berriozabal-Islas et al 2017.…”

“…Herpetofauna inside of the NPA´s have been analyzed in several studies from tropical environments of the world (Bruner et al 2001, Bell and Donelly 2006, Gardner et al 2007, Laurence et al 2012, but very few in tropical environments from Mexico (Vite-Silva et al 2010, Suazo-Ortuño et al 2015, Berriozabal-Islas et al 2017. These studies show a general pattern of species loss of the NPA´s toward surrounding and fragmented environments (Suazo-Ortuño et al 2015).…”

“…This difference could be explained by environmental heterogeneity among areas, which generates edge effect (Schlaepfer and Gavin 2001), and modification of the environment toward agroecosystems, such as shade coffee plantations (Pineda et al 2005), and land-use change involving grazing areas (Gardner et al 2007). For example, in two different studies by Bell and Donnelly (2006) and Berriozabal-Islas et al (2017), with amphibians and reptiles in the former, and with lizard in the last; in both studies the composition of communities was different to those preserved environments. These studies found a decrease in species richness and diversity to transformed environments.…”

“…When comparing these results with our data, it showed a different pattern, with a higher species richness, diversity and abundancy of amphibians and reptiles outside of the NPA than inside. Species richness and diversity recorded inside and outside of the NPA´s may differ among biological groups, being more significant in vertebrate group with low vagility, such as amphibians and reptiles (Pineda et al 2005, Berriozabal-Islas et al 2017) than those with high movements, as mammals (Caro 2001), or birds (Herremans 1998). This response is influencing by degradation and modification of the landscape around of an NPA (Laurence et al 2012), due to areas under protection are isolated and is generated an edge effect, and therefore, modifications in environmental parameters (e. g., temperature, solar radiation) and ecological (e. g., habitat and microhabitats availability) that affect population density (Pineda et al 2005).…”

“…Considering to the results showed in this study, where outside of the NPA is reported a higher number of species, higher functional diversity, and higher species number under high categories of conservation, we suggest the following measures to be considered in future studies that compare the herpetofauna inside and outside of an NPA´s: i) to analyze the status of conservation under different national (e. g., NOM-059), and international regulations (e.g., IUCN) of the species (Wilson et al 2013a, b, CruzElizalde et al 2016; ii) to evaluate ecotones among areas that comprise the NPA´s and surrounding environments (Pineda et al 2005); iii) to analyze species richness and diversity considering environmental factors, such as vegetal cover, temperature, solar radiation, and resources availability among different environments (Urbina-Cardona et al 2006, Vitt et al 2007, and iv) to evaluate the partition of the diversity at regional level and consider the functional and phylogenetic diversity of the communities inside and outside of the NPA´s (Cruz-Elizalde et al 2016, Berriozabal-Islas et al 2017.…”