Discipline: Ecology Environmental and Earth Sciences
Room: Exhibit Hall A
Rosebelle Ines - Humboldt State University
Co-Author(s): José-Cristian Martínez , Harper College, IL
Though tropical landscapes are the biodiversity hotspots of the world, some studies estimate that up to 36% of tropical forests are going to disappear by the year 2050. This disappearance can be accelerated by introduced exotic species because of their ability to modify invaded sites and alter nutrient cycling, which in turn threatens biodiversity and the overall ecosystem stability. In this study, we assessed whether the invasion of Zingiber spectabile (beehive ginger) alters the mean abundance of leaf litter arthropods across forest types at Las Cruces Biological Station in Costa Rica, since arthropods are ecological indicators used to detect anthropogenic impacts. We also determined if the degree of herbivory on Z. spectabile predicted the mean abundance of leaf litter arthropods across forest types. We hypothesized that the invasion of Z. spectabile would decrease the mean abundance of leaf litter arthropods in all forest types because leaf litter arthropods have not adapted to the environment created by the plant. We further predicted that the degree of herbivory on Z. spectabile would predict the mean abundance of leaf litter arthropods found across forest types since we expected a large proportion of herbivory to be produced by non-flying leaf litter arthropods such as ants. We sampled leaf litter arthropods by setting up 18 paired point comparison pitfall traps in invaded and non-invaded sites in primary, primary selectively logged, and secondary forest. Our results showed that the invasion of Z. spectabile had no significant effect on the mean abundance of leaf litter arthropods across all forest types. Rather, the mean abundance of these arthropods was significantly reduced due to habitat type, in this case, in the secondary forest (F2, 33 = 6.55, P = 0.004). Even though invasion had no significant effect, it does not necessarily explain the ability of Z. spectabile to alter the herbaceous community and the regeneration of other plants utilized by leaf litter arthropods as habitat or reproductive site. The significant decrease in the mean abundance of arthropods in the secondary forest was due to deforestation on the once, interconnected highland forest which has altered the secondary forest’s canopy structure and species composition. Since leaf litter arthropods rapidly respond to ecological changes, the large-scale disturbance posed a dramatic effect on their abundance. Contrary to our hypothesis on herbivory, the degree of herbivory predicted the mean abundance of beetles and crickets across forest types. Most of the beetles we collected were herbivores and detritivores and literature support that crickets increase consumption in the presence of predators. We recommend conducting further studies regarding the effect of Z. spectabile on leaf litter arthropods in comparison to native species in LCBS and incorporating environmental variables. Additional data will help make better decisions for the restoration and conservation of tropical landscapes.
Funder Acknowledgement(s): National Science Foundation -Organization for Tropical Studies Louis Stokes Alliances for Minority Participation REU Program
Faculty Advisor: José-Cristian Martínez, email@example.com
Role: I generated the research proposal, conducted field research, and wrote the manuscript. Further, I analyzed the data collected through R Commander, identified and sorted leaf litter arthropods under a dissecting microscope, and placed pitfall traps in sample sites across forest types.