Abstract

CRUZ-SALAZAR, Bárbara; RUIZ-MONTOYA, Lorena; NAVARRETE-GUTIERREZ, Darío  and  VAZQUEZ, Luis-Bernardo. Influence of the composition and structure of modified landscapes on abundance of two marsupials during the dry season. Therya [online]. 2016, vol.7, n.3, pp.393-406. ISSN 2007-3364.  https://doi.org/10.12933/therya-16-401.

Changes in the landscape due to habitat loss and fragmentation interact with ecological processes of populations, and define the local population abundance. We evaluated the relationship between the abundance of two common marsupials, Didelphis marsupialis (common opossum) and Didelphis virginiana (Virginia opossum), and landscape features in different levels of disturbance at Chiapas, the Highlands and the Central Depression. The goal was to identify effects of changes in the landscape in their populations. Based on the biological characteristics of D. marsupialis and D. virginiana our expectation was to observe higher abundance of opossums in areas with intermediate disturbance. At the same time, establish a relationship between the landscape composition and the abundance of both species. We placed 48 Tomahawk traps in three disturbance levels of the landscape. Within each disturbance level we obtained the structure and composition of the landscape. The abundance of each species was considered as the number of individuals captured. A relative abundance index was estimated from individuals captured by night traps. The influence of the disturbance levels, the landscape, structure, and composition in the abundance of each species was evaluated using multiple regression and generalized lineal model. The average abundance of Didelphis spp. was higher in the Central Depression (5.56 individuals, SD = 4.82). Didelphis marsupialis was captured only in low disturbance with an average of 0.56 individuals (SD = 1.04; Figure 2a), while D. virginiana was captured in the three levels of disturbance with an average of 3.56 individuals (SD = 3.88; Figure 2b). The presence of D. marsupialis was influenced by the number of patches (NP; P = 0.003), while for D. virginiana landscape index was not associated with its presence (Table 2). Our results suggest that the abundance of D. marsupialis and D. virginiana was not influenced by level of disturbance. However, D. marsupialis was related to the number of patches and conserved areas; while D. virginiana was not affected by the landscape attributes evaluated, i. e. composition and configuration, indicating that Virginia opossum can established relatively abundant populations in landscapes highly disturbed. This study contributes to the understanding of the effects of changes in the landscape in common species in Mexico due to human activities.

Keywords : common species; Didelphis; habitat loss; landscape; landscape fragmentation; mammals.

        · abstract in Spanish     · text in English     · English ( pdf )