Directed seed dispersal of Piper by Carollia perspicillata and its effect on understory plant diversity and folivory

Abstract

Directed dispersal occurs when seeds are differentially deposited to sites where offspring survivorship is higher than at randomly chosen sites. Traditionally, characteristics of the dispersal target sites that could increase survivorship of the dispersed plants are thought to be intrinsic to the sites. If directed dispersal is constant over extended periods of time, however, it is likely that nonrandom patterns of dispersal could modify the ecological characteristics of the target site in ways that could increase survivorship and fitness of the dispersed plants. Here we report patterns of Piper diversity (richness, equitability, and similarity) and Piper folivory within plots near natural or artificial roosts of Carollia perspicillata vs. similar plots without bat roosts. Plots with bat roosts, both natural and artificial, had significantly higher Piper species diversity. Additionally, we found that plots with a higher Piper species diversity showed less specialist folivory, higher generalist folivory, and lower total herbivore leaf damage than plots with low Piper diversity. Finally, plots with bat roosts also showed less specialist folivory, lower generalist folivory, and lower total folivory when compared to plots without roosts. We propose that long-lasting nonrandom patterns of seed dispersal can change the local ecological characteristics of target sites via changes in plant diversity, and that these changes are likely to reduce the local rates of folivory and, therefore, increase seed and adult plant survivorship.

Defensive fruit metabolites obstruct seed dispersal by altering bat behavior and physiology at multiple temporal scales

“…This causes many Piper seeds to be defecated beneath Carollia feeding roosts (Heithaus and Fleming 1978, Thies et al 2006, Salazar et al 2013. Immediately after a seed is ingested, C. castanea spends a median 13 minutes in the feeding roost (Appendix S1: Section 2.2.).…”

“…Even though the conclusions might be different if our data sets allowed us to control for taxon-specific variation, we do not believe that the general picture of our results would change significantly, as all Carollia species are light (10-20 g) understory frugivores with small home ranges, similar activity phases and comparable gut passage times (Fleming and Heithaus 1986;Thies and Kalko 2004;Fleming 2004, Thies et al 2006, Bonaccorso et al 2007. As many species in the genus of Piper are found even in small areas in lowland forests, and as fruit chemistry varies at within-plant, intraspecific, and interspecific scales, bats likely face a wide variety of choices with respect to fruit secondary compounds even within their small home ranges (Dyer et al 2004, Salazar et al 2013. 5 and 6) are not exact effects.…”

Connecting Resource Tracking by Frugivores to Temporal Variation in Seed Dispersal Networks

“…The directed dispersal hypothesis posits that natural selection will favor a dispersal interaction in which seeds are deposited into microclimates where they have a higher probability of germinating and surviving than they would in random sites (Howe and Smallwood, 1982). Successful dispersal events are important for altering local ecological characteristics of a site via changes in plant diversity (Salazar et al, 2013). In turn, these events affect the abundance of fruits within a neighborhood and the types of vertebrates within an area.…”

“…To date, directed dispersal has been disproportionately studied for specialized and rare plant species (Wenny, 2001;Loayza et al, 2014). Classic examples of directed dispersal include the dispersal of mistletoes into suitable sites within its host trees and ant-plant mutualisms (Wenny, 2001;Green et al, 2008;Salazar et al, 2013). However, directed dispersal does occur in common plant species such as, the tropical tree Ocotea endresiana, where dispersal largely occurs into favorable sites for seedlings due to bird perching behavior (Wenny and Levey, 1998), or to specific advantageous growth sites when corvid bird species cache pine cones or acorns (Vander Wall, 1990).…”

Interactions between frugivorous bats (Phyllostomidae) and Piper tuberculatum (Piperaceae) in a tropical dry forest remnant in Valle del Cauca, Colombia

“…compared to other places without nearby shelters. Seed dispersal is therefore directed and nonrandom (Salazar, Kelm, & Marquis, 2013). As a result, habitats devoid of resources, or actively avoided by dispersers (e.g., due to the incidence of predators), will receive a lower seed rain, which will lead to decreased diversity (Estrada-Villegas, Pérez-Torres, & Stevenson, 2007).…”