Biotic heterogeneity among scarab beetle communities in an anthropized landscape in the Central Valleys of Oaxaca, Mexico

Abstract

In the tropics, changes in land use are a major concern given that the transformation of natural ecosystems to degraded environments for human use occurs rapidly and is associated with deforestation, fragmentation, isolation, among other impacts. Scarab beetles are well represented in tropical and warm temperate ecosystems due to their high diversity, numerous ecological functions, sensitivity to habitat disturbances, and responses to anthropized areas, so they are considered as a model group to study the consequences of environmental disturbance in tropical regions. We present an analysis of the scarab beetle diversity in an anthropized landscape with five different land uses in the Central Valleys of the state of Oaxaca, Mexico, with an emphasis on the dissimilarity in species composition. The organisms were collected with dung-, carrion- and fruit-baited traps during five sampling periods. We identified 2766 individuals belonging to 40 species, the majority being coprophagous or copro-necrophagous. The most abundant species was Phanaeus nimrod, with 624 individuals, although the most abundant species changed according to land uses. Beta diversity was high (80% on average), and between four sites dissimilarity was 100%. Species replacement was more important than differences in richness for the total beta diversity calculated with incidence data; and balanced variation in abundance was more important than the abundance gradient in the case of analyses with abundances. The landscape presented high scarab beetle diversity, mainly due to a high species replacement and the balanced variation in abundance, indicating that a high biotic heterogeneity has been maintained, or even enhanced following landscape modification.