2025 | The Eco-Evolutionary Diversity of Grassland to Forest Gradients in the South American Orinoquia
FACULTY SEED GRANT | Global Change Center
The eco-evolutionary diversity of grassland to forest gradients in the South American Orinoquia
INVESTIGATORS:
- Dr. Valentina Gómez-Bahamón, Biological Sciences
- Dr. Rachel Reid, Geosciences
- Dr. Julie Allen, Biological Sciences
- Dr. Sergio Estrada-Villegas, Universidad del Rosario, Colombia
Grasslands are an overlooked imperiled habitat. They are usually the first targets for land transformation into crops and cities. Such transformations have caused the rates of decline to be much steeper for grassland species than for other habitat types. For example, in North America 74% of grassland bird species are declining rapidly. Therefore, we think conservation priorities should focus on a community-level approach. Moreover, grasslands do not occur in isolation; forests and rivers can surround large tracts of grasslands, like in the South American Orinoquia. However, we do not know how species from these grasslands interact (compete or cooperate) with species from the surrounding forests, or how traits and communities change as we go from this grassland-to-forest gradient.
Bird communities in grasslands and contiguous riparian forests in the Orinoquia are rich and strikingly different. Thus, beta diversity at small spatial scales is high. There is also heterogeneity in vegetation structure and composition, which is crucial to maintain bird diversity. Today, grasslands in Orinoquia are cleared to plant exotic timber species. There iseven a call to transform these grasslands into forests to mitigate climate change. Monocultures have risen at an unprecedented rate given technological advances that allow crops to grow year-round. For example, the cultivation of soy, corn, and oil palm has transformed thousands of hectares of these South American grasslands. Additionally, cattle farmers prefer pastures with exotic trees for shading instead of native trees. With cattle and agricultural intensification, we are losing grasslands quickly.
Our project aims to quantify the turnover, nestedness, and niche overlap of diversity attributes in bird communities across a grassland-to-forest gradient in Orinoquia. The overarching goal is to understand how these habitat types are interconnected and incorporate those dynamics into models that reconstruct the eco-evolutionary processes that have led to regional diversity. Our quantification will serve to highlight grasslands-to-forest equilibrium, the importance of both habitats for Orinoquia, and inform future land-use practices to maintain diversity. Specifically, we propose to 1) quantify species turnover, nestedness, and overlap of functional, morphological, and taxonomic bird diversity within and between contiguousgrasslands and forests, 2) estimate community level measures of functional diversity by identifying the identity and abundance of their diet through fecal metabarcoding and stable isotope analyses, and 3) incorporate evolutionary history to understand how community assemblage is composed across and between these habitats.
Each year, the GCC, with funding from the FLSI and the ISCE at Virginia Tech, accepts proposals from GCC faculty to support interdisciplinary research that will lead to collaborative proposals submitted to extramural funding sources. We are seeking projects that link multiple faculty programs and take advantage of unique combinations of expertise at VT, have societal implications and/or a policy component, deal with emerging global change issues that have regional and global significance, and have high potential to eventually leverage external resources.
