How does fragmentation influence community assembly?

Landscape fragmentation is a leading cause of global declines in biodiversity.  Regardless of whether a community is disassembling or assembling, diversity is lower in smaller, more isolated habitat patches. To better understand the mechanisms driving this pattern, I’ve been studying how the identity, order, and rate at which plant species undergo colonization and extinction depends on the spatial configuration of habitat. Much of this work takes place at University of Kansas Field Station Fragmentation Facility, where a long-term, landscape-scale experiment has been running since 1984.

Landscape Ecology of Seed Pathogens

With collaborator Michelle Hersh, I am testing the hypothesis that patch size influences seed pathogen composition and diversity. Combined with studies of seedbank composition and dynamics, we aim to understand the role pathogens play in generating patterns of plant diversity in fragmented landscapes. This study was recently funded by the National Science Foundation 

Tropical rainforest restoration

In many ecosystems, restoration efforts aim to maximize local diversity based on the assumption that diversity leads to greater primary productivity. Positive relationships between diversity and productivity are commonly observed in grassland systems were experimentation is straightforward, but less is known about slower-growing, larger-scale communities such as forests. In the tropics, species –rich restorations may not be feasible if local nurseries have only a limited numbers of native species available for planting. In these cases, local diversity and productivity in forests might best be maximized by altering evenness. At Firestone Center for Restoration Ecology (FCRE) in Costa Rica, we are exploring the consequences of varying evenness for aggregate community properties such as primary production and decomposition in an experimental rainforest restoration.

Ethiopian Church Forests

In most tropical regions, forests continue to be cleared for agriculture, firewood, grazing and human settlements. In Ethiopia, forests surrounding Orthodox churches, where church leaders and communities have preserved forests as sacred sanctuaries – in some cases for over 1500 years, are a notable exception. From an ecological perspective these ancient forest fragments house the bulk of Northern Ethiopia’s remaining native biodiversity. From an economic perspective, church forests provide important and valuable environmental goods and services, ranging from cultural values to tangible products such as food, fodder, firewood and freshwater springs, crucial for local water supplies. Our research team (myself, with collaborators Travis Reynolds, Meg Lowman, and Dr. Alemayehu Wassie) leads a site-based, NSF-funded REU program to investigate the cultural, economic and ecological significance of Church Forests in South Gondar, Ethiopia.