Competitor Richness Outweighs Climate and Land Cover in Explaining Abundance Variation of a Neotropical Fruit Bat

Abstract

Understanding which processes regulate spatial variation in species abundance across their ranges is key in ecology. Species abundances may be affected by several factors, such as climate, elevation, land cover, species interactions and habitat protection status. However, few studies have focused on these effects synergistically across species ranges. Here, we evaluate how these factors affect the relative abundance of the Flat-faced Fruit-eating Bat Artibeus planirostris (Spix, 1823) (Chiroptera, Phyllostomidae) across its range. We obtained relative abundance data of A. planirostris through a literature review. We used temperature seasonality and precipitation seasonality as climate variables, elevation as topography, forested primary land and rangeland as fractional land cover patterns, species richness of potential competitors as a proxy for species competition, and habitat protection as protected (if within a protected area) or unprotected (if outside a protected area). We used multiple regression to assess the effects of the environmental variables on the relative abundance of A. planirostris, and we applied a spatial error model to control for spatial autocorrelation. Most localities exhibited a low abundance of A. planirostris. It is more abundant in the Pantanal and in the Caatinga. Protection status, rangeland and precipitation seasonality affected positively the abundance of A. planirostris, whereas competitor richness, elevation and temperature seasonality affected it negatively. Our results showed that competitor richness is the strongest predictor of the relative abundance of A. planirostris, which suggests that the presence of many competitors may have an important role in decreasing bat abundance. This pattern is consistent with expectations under the diffuse competition framework. Interestingly, protection status had a positive effect on its abundance, confirming that even common species benefit from protected areas. We can conclude that species interactions may be more important than previously thought to explain the spatial variation of species abundance than climate, topography and land cover.