The Role of landscape in contact zones of sister species of lizards

CARDOZO, GABRIELA; NARETTO, SERGIO; ZAK, MARCELO; CHIARAVIGLIO, MARGARITA

Perspectives on Nature Conservation, Patterns, Pressures and Prospects

InTech

Año: 2012; p. 161 - 176

Elucidating the factors regulating the spatial distribution of ecologically similar species is a key pursuit. Many biotic and abiotic variables might influence species distribution and determine allopatry or simpatry. Moreover, species patterns are strongly associated with habitat variables at different spatial scales. However, the role of landscapes in contact zones is not completely understood. The geographic structure of contact zones determines dynamic evolutionary processes; however, since landscape structure influences population processes the maintenance of contact zones is likely to depend on landscape patterns. Morphological similarity among coexisting animal species induces potential interactions that may lead to niche segregation. Interspecific competition might favour niche differentiation between competitors because it may optimise their behaviour in different ways. Thus, niche differentiation in ecologically similar species might induce divergence of landscape-scale habitat use. In this work, we focused on two closely related lizard species: Tupinambis merianae and Tupinambis rufescens. Considering that habitat loss is a serious environmental problem in many ecosystems, the conservation status of landscapes in key wildlife habitats, such as contact zones, becomes strikingly relevant for species conservation. Understanding the associations between landscape conservation status and the distribution of sister species in contact zones could be useful to design conservation plans not only for individual species but also for ecological systems. We examined landscape-scale habitat use in contact and allopatric zones between the two teiid lizards. The novelty of our approach lies in the importance of landscape conservation to the maintenance of ecological interactions between lizard sister species. Our results indicate that T. rufescens and T. merianae have complex habitat requirements. Since T. rufescens and T. merianae showed differences in landscape-scale habitat requirements, planning of conservation strategies should consider such interspecific heterogeneity. When we analyzed niche differentiation in terms of landscape-scale resources, we observed that species did not differ in the use of landscape resources in contact zones. Both species used landscapes with similar proportions of land-cover types, mean patch area and number of patches. Tupinambis merianae both in allopatry and sympatry used similar landscapes. By contrast, T. rufescens in allopatry and sympatry used the landscape differentially, showing niche modification. Our study provides useful knowledge about the important role of native forest and shrublands in allopatric and sympatric distribution areas of the lizard species. Furthermore, similar allopatry-simpatry systems might be occurring in this contact zone, which coincides principally with the arid South American Gran Chaco. Efforts to prevent habitat loss should involve preserving not only allopatric areas but also these critical heterogeneous sympatric areas where biological interactions might modify ecological processes of species.