Early biogeographers such as Alexander von Humboldt recognized the broad-scale coupling of vegetation and climate. This observation shaped the modern biome concept which organizes ecosystems by assumed relationships to environmental controls. Biomes are essential constructs for understanding vegetation distributions, the evolutionary patterns that shape species pools, and the environmental impacts of human activities, among other applications. However, ecologists recognize that there are regions, especially in the tropics, where vegetation may not deterministically relate to climate. This contrasts with the current biome concept, which is operationalized in practice as a static classification of the land surface. Process models rely on these classifications to summarize vegetation into Plant Functional Types (PFTs) which form the basis for representing ecosystem function and biogeochemical rates. Recently this approach has been criticized for missing key impacts on the distribution and functioning of biomes like historical contingency, biogeographic history, disturbance ecology, and evolution. Thus, further research is required to better define biomes based on species composition and phylo-functional diversity, as well as better understand the drivers of biome boundaries and functioning within and among biomes. A new understanding of biomes is crucial for appropriate prediction of future environmental change and global biogeochemical cycle modeling based on highly abstracted PFTs. Some of the overarching questions that interest me include:

• What are the drivers of vegetation distributions, and to what extent are non-climatic factors important?
• At what scale (grain and extent) are biotic versus abiotic filters important determinants of community assembly?
• How do plant traits and evolutionary trade-offs among traits contribute to ecological functioning?
• Can our research be translated into improved representation of grass biogeography in earth system models?
• Can our research be translated into improved conservation outcomes?

Research Topics

Savanna and grassland conservation - Grass-dominated ecosystems are threatened by land-cover conversion and climate change. The loss of grasslands and savannas is exacerbated by pervasive misclassification of savannas as degraded forests and a lack of basic information about the origins and diversity of grass-dominated ecosystems. Savanna ecosystems, in particular, are difficult to delineate climatically because of their unique relationships with disturbances, such as fire and grazing, and the dynamics of tree-grass coexistence. Grasses likely played an important role in early human evolution and they currently feed livestock and provide the bulk of humanity’s calories. Grasses dominate roughly one-quarter of the terrestrial biosphere, are a major component of the global carbon cycle, and support some of Earth’s most dynamic foodwebs. Thus, grasses are absolutely central to a wide range of ecological and environmental challenges. However, since grass-dominated ecosystems have partly non-climatic and disturbance driven distributions, conserving them requires basic research linking local dynamics to the evolutionary innovations conferring ecological dominance to particular clades of grasses. My research focuses on the influences of disturbance, evolution, and biotic interaction along environmental gradients at local, regional, and global scales.

More project info to come, under construction…