Response of rodent assemblages to change in habitat heterogeneity in fruit-oriented nopal orchards in the Central High Plateau of Mexico

摘要

In the Central High Plateau of Mexico, perennial nopal (Opuntia spp.) orchards are used by several native rodent species. The effect of orchard aging on habitat heterogeneity and rodent assemblages are not known. I surveyed rodent community abundance, species richness, diversity and composition, and habitat heterogeneity (hab-H) in 3 nopal orchards-6 months (O1), 2 years (O2), and 12 years (O3) old-and 1 natural nopalera (NN). Hab-H increased with orchard age, and a unique rodent assemblage was associated with each nopal orchard. Grassland rodents dominated O1 and O2. The shrubby habitat of O3 supported a complex suite of rodents that included grassland and shrubland species, and the NN supported a rodent assemblage that was dominated by shrubland species. In O3, aging of the orchard had led to a hab-H and establishment of a rodent assemblage resembling that of NN. Similar ecological relationships are expected in other nopal orchards of the region. In view of my data, regional conservation efforts should take advantage of the mosaic of differently-aged nopal orchards, because they offer suitable conditions for different species of native rodents, particularly given that some of these species occupy natural habitats that are currently highly fragmented.