Howeth Lab Research
Research in the Howeth Lab integrates population, community, and ecosystem-level processes across multiple scales to better understand determinants of species diversity and ecosystem properties. Recently, the importance of space in mediating population connectivity and local species interactions has become increasingly recognized by ecologists and evolutionary biologists. This interest in spatial ecology has largely arisen from the urgent need to understand how fragmented landscapes alter dispersal and gene flow of threatened species, and how species invasions affect species richness and ecosystem functioning. Over the past decade, the metapopulation and metacommunity concepts have emerged as powerful frameworks in which to place population demography, community interactions, and ecosystem properties in a spatially explicit context. Research in the lab employs experimental and observational approaches to extend this theory to diverse species and landscapes. To date, we have conducted field research in: the ponds of Alabama and Michigan; the lakes and reservoirs of Alabama, California, Texas, and New England; and the arid wetlands of the Cuatro Ciénegas Biosphere Reserve in Mexico.
Despite the broad geographic extent of our work, members of the lab maintain a focus on mechanistic studies with shared, mutually informative research themes in community, landscape, and ecosystem ecology. Find out more about our current research below.
Despite the broad geographic extent of our work, members of the lab maintain a focus on mechanistic studies with shared, mutually informative research themes in community, landscape, and ecosystem ecology. Find out more about our current research below.
Species diversity and ecosystem properties in metacommunities
The metacommunity concept provides a framework that describes and forecasts effects of community connectivity (species dispersal rates) on species diversity and ecosystem properties across hierarchical spatial scales in a landscape. Our research in metacommunities is situated at the interface of local and regional spatial scales, and integrates food web interactions to understand processes affecting multi-scale diversity and trophic structure. Our previous research in pond and lake metacommunities addressed the influence of spatially and temporally heterogeneous predation (invertebrate, fish) on plankton metacommunity structure, and the effect of intraspecific variation in fish on multi-scale and multi-trophic diversity. Current research addresses:
Invasion
We use non-native aquatic species (e.g., Daphnia lumholtzi, Dreissena bugensis, Dreissena polymorpha) to take a mechanistic and trait-based approach towards understanding the process and impacts of biological invasion within ecological communities. This work combines observational studies in reservoirs and experimental approaches in mesocosms. Associated applied research includes the development of invasion risk assessment models for dreissenid mussels and reservoirs in the southwestern US.
Invasion
We use non-native aquatic species (e.g., Daphnia lumholtzi, Dreissena bugensis, Dreissena polymorpha) to take a mechanistic and trait-based approach towards understanding the process and impacts of biological invasion within ecological communities. This work combines observational studies in reservoirs and experimental approaches in mesocosms. Associated applied research includes the development of invasion risk assessment models for dreissenid mussels and reservoirs in the southwestern US.
Succession
We evaluate the role of succession in metacommunity structure using beaver-formed ponds and associated streams in the Talladega National Forest, AL as a model system. We study the response of fish, zooplankton and crayfish communities to pond age. Additionally, we are interested in how food chain length changes across the chronosequences of replicate successional pond mosaics.This work combines traditional sampling methods and DNA barcoding to characterize species diversity across temporal and spatial scales. Future studies will integrate mesocosm experiments to better isolate mechanistic responses underlying observed patterns of diversity.
Diversity and Ecosystem Function
With our new mesocosm facility at University of Alabama's Tanglewood Biological Station, there are several opportunities for graduate and undergraduate students to mechanistically test questions about the role of species dispersal and diversity in influencing community invasibility, community response, and ecosystem function using plankton communities. This is a future research area of the lab that builds on our previous and current studies. There is opportunity to develop independent research projects strongly grounded in theory.
Trait-based invasive species risk assessment
A collaborative research effort develops trait-based invasive species risk assessments for non-native fishes in North America. The research focuses on identifying traits of non-native fish which are associated with different stages of invasion. Comparative studies of non-native fish communities in multiple regions of North America that differ in spatial extent, environment, and regional native species pool elucidate region-independent patterns of important and shared traits associated with invasion. Additionally, this research identifies non-native fish species in international trade (e.g., aquarium, live-food) which pose a threat to freshwater ecosystems across North America. This integrative science informs community ecology theory, management practices, and environmental policy.
