Effects of Artificial Roosts for Frugivorous Bats on Seed Dispersal in a Neotropical Forest Pasture Mosaic

Abstract

In the Neotropics ongoing deforestation is producing open and heavily fragmented landscapes dominated by agriculture, mostly plantations and cattle pastures. After some time agriculture often becomes uneconomical and land is abandoned. Subsequent habitat regeneration may be slow because seed inputs are restricted by a lack of incentives--such as suitable roost sites--for seed dispersers to enter deforested areas. Increasing environmental awareness has fostered growing efforts to promote reforestation. Practical and cost-efficient methods for kick-starting forest regeneration are, however, lacking. We investigated whether artificial bat roosts for frugivorous bat species can attract these key seed dispersers to deforested areas, thereby increasing seed rain. We installed artificial bat roosts in a forest-pasture mosaic in the Costa Rican Atlantic lowlands and monitored bat colonization and seed dispersal. Colonization occurred within a few weeks of installation, and 10 species of bats occupied the artificial roosts. Five species of frugivorous or nectarivorous bats colonized artificial roosts permanently in both primary habitat and in deforested areas, in numbers similar to those found in natural roosts. Seed input around artificial roosts increased significantly. Sixty-nine different seed types, mostly of early-successional plant species, were transported by bats to artificial roosts in disturbed habitats. The installation of artificial bat roosts thus successfully attracted frugivorous bats and increased seed inputs into degraded sites. This method is likely to speed up early-vegetation succession, which in turn will attract additional seed dispersers, such as birds, and provide a microhabitat for seeds of mid- and late-successional plants. As well as supporting natural forest regeneration and bat conservation, this cost-efficient method can also increase environmental awareness among landowners.

Bat (Chiroptera) assemblages in three Cerrado fragments of Mato Grosso do Sul, southwestern Brazil

“…In the Cerrado in particular, bats have been shown to be important pollinators, carrying pollen long distances between isolated tree stands (Moraes and Sebbenn, 2010). Further, by dispersing seeds, especially those of important pioneer species, phyllostomid frugivores play a role in the secondary succession and the regeneration of degraded forests (Gorresen and Willig 2004;Kelm et al 2008;Kunz et al 2011). Given these ecological functions and their importance for human activity, declines in bat populations and species richness are cause for concern.…”

Roosting Ecology of Amazonian Bats: Evidence for Guild Structure in Hyperdiverse Mammalian Communities

“…Although some structures used as diurnal refugia-such as tree cavities and foliage-are seemingly abundant in many habitats, careful study of roost characteristics suggest that bats are highly selective about where they roost (Kunz and Lumsden, 2003), so ideal refugia may often be in short supply. The prompt colonization of artificial roosts deployed in experimental studies (e.g., Kelm et al, 2008) and the frequent use of manmade structures (buildings, bridges, culverts, etc. ) as roosts support similar conclusions.…”

Does any bat box facilitate forest recovery? – Reply to Kelm

“…A goal of our study was to test the hypothesis advanced by Kelm et al (2008) that ''Artificial roosts may act as nuclei for forest recovery in a similar fashion to isolated trees in abandoned pastures.'' To do so, we installed artificial roosts in abandoned pastures and monitored them for bat visitation, seed dispersal, and seedling recruitment.…”

“…This concern is unfounded because abandoned pastures characteristically have high temperature and light levels, and these areas are precisely where seed rain limits regeneration. In retrospect it may seem obvious that bats would not prefer artificial roosts in hot, dry pastures, but this was a critical assumption of the bat-roostsas-isolated-trees hypothesis (Kelm et al, 2008).…”