Reptile diversity in a Mediterranean wetlands landscape (Alto Guadalquivir region, southeastern Spain): are they affected by human impacts?
Arancha de Castro-Expósito, Departamento de Biología Animal, Biología Vegetal y Ecología
Enrique García-Muñoz, Departamento de Biología Animal, Biología Vegetal y Ecología
Francisco Guerrero, Departamento de Biología Animal, Biología Vegetal y Ecología
Species extinction is a natural process, but in recent times there has been a more general decline in biodiversity with a species extinction rate that is estimated to be higher than it might be expected (Rockström et al., 2009; De Vos et al., 2014). The decline in biodiversity has been reported by many authors, and different causes have been considered in order to understand the complexity of join-ing cause and effect, being human activities identified as a crucial threat (Wake and Vredenburg, 2008; Pimm et al., 2014; Ripple et al., 2019). In this process of loss of diversity, herpetological fauna is one of the groups with the highest risk of extinction (Böhm et al., 2013; Alroy, 2015).
The report of the International Union for Conservation of Nature (IUCN, 2010) reflects this critical situation, indicating that 41% of the amphibians, and 28% of the reptiles evaluated are critically threatened. As with other vertebrate groups, the main reasons behind decline are climate change (Foufopoulos et al., 2011), destruction and alteration of their habitats (Lizana and Barbadillo, 1997; Wake and Vredenburg, 2008), ecosystem pollution (Sparling, 2003; Sparling et al., 2015) or the introduction of allochthonous species (Pleguezuelos, 2002), among others. In the Iberian Peninsula there are 56 species of reptiles (Márquez and Lizana, 2002). One of the most important threats to these species is the destruction of habitats, as a consequence of the mechanization of the agroecosystem since the Industrial Revolution (Ceacero et al., 2007).
The establishment of monocultures, due to intensive agriculture, has led to a homogenization of the ecosystem, characterized today by simplistic mosa-ic models, which has caused a reduction in biodiversity and to the loss of natural habitats (Guerrero et al., 2006; García-Muñoz et al., 2010, 2016). Th is simplification of the agroecosystems has been widely linked to the excessive use of agrochemicals that are endangering many species (Sparling et al., 2000; Mann et al., 2009; Böll et al., 2013; García-Muñoz et al., 2019). In fact, many species of reptiles live in highly specific environments, have very restricted distributions and population growth to very slow rates (Pleguezuelos et al., 2002). Accordingly, the presence of some species of reptiles or the state of their populations will depend, among other factors, on the characteristics of the species and to what extent the habitats have been disturbed (Pleguezuelos, 2002).Therefore, the aim of this research was to determine the status of the reptile populations in different wet-lands of the Alto Guadalquivir region (Andalusia, south of Spain), in connection to the different types of land use established in the surrounding drainage basins. Th e hypothesis in this study was that the wetlands in which a greater number of habitats were conserved in their drain-age basins would have reptile populations with higher diversity and abundance compared to those in which intensive monoculture had been established. In order to test this hypothesis, we proceeded to (i) determine the different types of land use in the drainage basins of each wetland; (ii) determine the presence/absence, abundance and size structures of the different reptile species in each wetland under study; and (iii) determine how the conservation status of the wetland drainage basin influenced reptile communities. Th e results from this research could enable us to propose conservation measures to be implemented for the reptile species present in the wetlands.
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