Effects of land-cover changes on mammals in a neotropical region: a modeling approach

Land-cover changes translate into shifts in habitat available to wildlife s pecies. I analyzed the effects of land-cover changes on habitat availabilit y for 54 mammal species in a 2.7 million-ha area in southern Mexico and nor thern Guatemala. I considered the regional variability of these changes and the effect of variation in management and development trends. Using cluste r analysis, I grouped mammal species into assemblages with similar associat ions of land-cover type. Based on data from a remote-sensing, land-cover ch ange analysis (1974-1986), I created simple linear Markov models for a heur istic tool to simulate land-cover changes over a 60-year period and to expl ore temporal trends of change in habitat availability for the mammal specie s. I used elasticity analyses to identify land-cover transition probabiliti es critical for these trajectories. Of the 12 land-cover classes considered , four dominated the area: grasslands, tropical secondary vegetation, tropi cal moist forests, and wetlands. Transition probabilities to and from these four land-cover types were key in determining the availability of habitat for mammals. Thus, the relatedness of mammal species to these land-cover ty pes seems critical for their long-term persistence in the region. According to general stimulated trends in fluctuation of habitat availability, I cla ssified species into seven categories: (1) opportunistic and highly adaptab le species, occupying most of the area; (2) opportunistic, human-commensal species, with restricted range in the study area; (3) species with stable a nd moderate habitat availability (4) species with moderate bat increasing h abitat availability; (5) species with originally moderate but declining hab itat availability; (6) species with already reduced and sharply declining h abitat availability; and (7) species with declining habitat availability an d a restricted range. Markovian trajectories suggest a declining trend of h abitat availability for 32 species (59%). Land-cover change trends however were highly variable between the nine subregions. As a result, habitat avai lability for many species varied regionally. Likewise, changes in managemen t and development policies and trends in the study area will lead to contra sting habitat availability for declining and increasing species, but not fo r the rest of the species. The approach I used is useful for (1) assessment of land-cover changes resulting from different development trends and mana gement practices and (2) exploration of how changes may affect species habi tat availability and survival perspectives. This examination can be accompl ished for a substantial part of a biota and for entire regions, even in the context of limited information.