This whole experience during our field course in Costa Rica has been one big adventure, but my research project in itself has definitely added to this sentiment. As I briefly described in my first post, I am interested in how the difference in conditions and abundance of certain trees indicate the health of forest types. It’s probably no surprise to you, but the more human-dominated a forest is and as deforestation increases, the more unhealthy a forest becomes, and biodiversity is compromised as the forest evolves to be unfit to sustain wildlife (Broadbent, 2012). Fortunately though when extinction has occurred in a forest because of this, it is able to regain some of that lost health and bring back some of those lost species, when restoration is allowed to take place over the course of several years (Daily, 2003).
For my research project this summer, I wanted to assess the difference in forest composition across different types of land use to determine how suitable these forest fragments are in their ability to sustain wildlife. A tree species that is particularly telling of forest health is fig trees, or trees of the Ficus genus, because there are over 800 species in the genus and as it fruits all year round, fig trees are an important food resource for many animals (Harrison, 2005). I expected to see less fig tree abundance as fragments were more dominated by human use, indicating that these fragments are an unsuitable habitat for wildlife.
My research partner, Danica, wanted to assess forest health amongst land use types as well, but through bird species richness as it is contained in these different human dominated forest fragments. The pairing of both of our project ideas couldn’t have been better because both tree abundance and bird species richness are great indicators of forest health. This is mainly due to this: You can’t have birds without trees and because seeds are often dispersed by birds, you can’t have trees without birds. So our project this summer worked to identify a correlation between bird species richness and fig tree abundance between different land use types. We looked at primary forest, abandoned pastures, and a coffee farm to assess these items and it turned out to be more of an adventure than we expected.
Our project required us to go out into the field at 4:30 am because birds are the most active at this time, and as we ventured through the forest in the dark, we were often faced with different obstacles. This included climbing up slippery hills, dodging pesky insects, and even walking through a river. As we picked ourselves up every time we fell, we learned many things about doing this type of research. Mainly, time is a huge factor as it really takes time to plan and execute these types of projects.
Also, it turned out that fig tree abundance didn’t change too much between the different land use types, but total tree abundance definitely did. I counted over 700 trees in a primary forest transect and about only 100 in a transect in the coffee farm. In terms of fig tree abundance, I saw the most fruiting fig trees in the pastures that have been able to restore themselves for the past 10 years. This was due to fig trees being planted intentionally as they were part of a fence in the past, and this was an effort to bring wildlife back to these regions. Also due to our sample size, the differences in bird species richness across the land types that Danica saw didn’t show a significant relationship.
So it turned out that with tree coverage, it showed results that we would expect because they were the most abundant in places with the least human dominance, but with the fig trees being the most in the pastures, human decisions do greatly affect fig tree abundance. And our results with bird species didn’t turn out as expected either. Sometimes your results don’t turn out as planned but something more influential may pop up. After all, that’s science.
Well, I’ve enjoyed my time in Costa Rica greatly, but I am looking forward to be back in Austin next week. Adios, y’all!
P.S. I had pictures I wanted to post but they wouldn’t upload because the internet down here has been spotty. Oh well, pura vida.
Broadbent, E. Zambrano, A. Dirzo, R. et al. 2012. “The effect of land use change and ecotourism on biodiversity: a case study of Manuel Antonio, Costa Rica, from 1985 to 2008”. Landscape Ecol. 27: 731-744.
Daily, G. Ceballos, G. Pacheco, J. et al. 2003. “Countryside Biogeography of Neotropical Mammals: Conservation Opportunities in Agricultural Landscapes of Costa Rica”. Conservation Biology. 17(6): 1814-1826.
Harrison, R. 2005. “Figs & the Diversity of Tropical Rainforests”. BioScience. 55(12): 1053-1064.