Tropical secondary forest management influences frugivorous bat composition, abundance and fruit consumption in Chiapas, Mexico

Abstract

Most studies on frugivorous bat assemblages in secondary forests have concentrated on differences among successional stages, and have disregarded the effect of forest management. Secondary forest management practices alter the vegetation structure and fruit availability, important factors associated with differences in frugivorous bat assemblage structure, and fruit consumption and can therefore modify forest succession. Our objective was to elucidate factors (forest structural variables and fruit availability) determining bat diversity, abundance, composition and species-specific abundance of bats in (i) secondary forests managed by Lacandon farmers dominated by Ochroma pyramidale, in (ii) secondary forests without management, and in (iii) mature rain forests in Chiapas, Southern Mexico. Frugivorous bat species diversity (Shannon H') was similar between forest types. However, bat abundance was highest in rain forest and O. pyramidale forests. Bat species composition was different among forest types with more Carollia sowelli and Sturnira lilium captures in O. pyramidale forests. Overall, bat fruit consumption was dominated by early-successional shrubs, highest late-successional fruit consumption was found in rain forests and more bats consumed early-successional shrub fruits in O. pyramidale forests. Ochroma pyramidale forests presented a higher canopy openness, tree height, lower tree density and diversity of fruit than secondary forests. Tree density and canopy openness were negatively correlated with bat species diversity and bat abundance, but bat abundance increased with fruit abundance and tree height. Hence, secondary forest management alters forests' structural characteristics and resource availability, and shapes the frugivorous bat community structure, and thereby the fruit consumption by bats.

Figure 1. Comparisons of different parameters among forest types.

Bars representing; (a) frugivorous bat diversity (Shannon H’), (b) log frugivorous bat abundance and (c) bat fruit consumption diversity (Shannon H’). Bars with equal letters are not significantly different; based on a two-tailed Hutcheson t-test for the frugivorous bat diversity and bat fruit consumption diversity and an ANOVA and Tuckey post-hoc test for the comparison of bat abundance.

Figure 2. Non-metric multidimensional scaling (NMDS) ordination based on Bray-Curtis dissimilarity of frugivorous bat species abundance and the associated significant environmental variables.

Sites: 1-4 O. pyramidale managed forests, 5-8 secondary forests and 9-12 rain forests. Directions of arrows indicate increasing variable value. Italic letters represent frugivorous bat species names, with 1st letter for genus and 2nd letter for species (exception: Centurio senex is C. sx; see Table 1).