I am interested in one of ecology´s fundamental questions: what are the patterns of biodiversity? As well as in one of today´s most pressing questions: how will biodiversity and ecosystem processes respond to a changing environment? Most of my work has focused specifically on tropical forest canopies where I use multiple ecological approaches to better understand the factors that control species richness and distribution, and on the abiotic and biotic threats to these communities. I have recently expanded my research to two other ecosystems, the temperate deciduous forests of the Adirondack Mountains, NY, and the Tropical Dry Montane forests of northern Ethiopia. While disparate in location and ecosystem-type, these studies are grounded in the same scientific framework: the community ecology and nutrient dynamics of forests. These sites are linked in that they are threatened by disturbance: the rainforest canopy and the forests of northern Ethiopia by water loss due to increased temperatures, increased nutrient deposition, and by deforestation; the forests of the Adirondacks by Acid Rain and increased nutrient deposition. My lab uses observational and experimental approaches that combine community and ecosystem ecology to study the impacts of these disturbances.
The position of epiphytes at the interface between the atmosphere and the forest floor means that epiphytes are likely to receive the brunt of the predicted increases in nutrient deposition from anthropogenic sources. How the epiphyte layer responds to these inputs may have significant effects on canopy processes, biodiversity, and community structure as well as forest floor nutrient processes. For this reason, I wrote a grant proposal for and received funding from the National Science Foundation, to develop a mechanistic understanding of the effects of direct nutrient addition to canopy plants on canopy ecosystem processes, diversity, and ecosystem structure. The approach for the above objectives is an experiment with three nutrient addition treatments and one control: nitrogen addition, phosphorus + cation addition, nitrogen + phosphorus + cation addition.
In the Debre Tabor region of Ethiopia, the remaining ‘intact’ forests are those surrounding churches (Figures 3 & 4). These patches currently exist as islands in a sea of degraded land, providing sanctuary to many endangered plant and invertebrate taxa of Ethiopia (Bongers et al. 2006). These forests are valuable to local people because they provide essential ecosystem services such as fresh water, shade, honey, pollinators and spiritual value.
Liming as a Mitigation Strategy in Northeastern US Forests
Acid rain depletes forest soils of base cations (calcium, magnesium, and potassium) which are essential micronutrients for healthy soil and plant function. This has led to slower regeneration of forests, mass die-offs of canopy trees, and a more vulnerable ecosystem. My lab is examining the effects of calcium addition, a potential small-scale mitigation strategy, on forest nutrient recovery. We are examining this in belowground processes, in the top 10 cm of the soil, and in aboveground processes, tree leaf tissue, leaf litter production, and leaf litter decomposition.