Ecological research
I study population ecology of diverse taxa. Specifically, I focus on aspects of variation within species and communities, microbial community dynamics, and the relationship between rarity and vulnerability.
Much of my work involves collaboration with colleagues. Please see publications for full list of coauthors.
Much of my work involves collaboration with colleagues. Please see publications for full list of coauthors.
How to survive as a rare endemic species?
Species may be rare for a variety of reasons, and surviving as a rare species can be a challenge. For endemic species that exist in small, isolated populations, the risk of extinction is particularly high. Despite this risk, some of these species persist in remarkably stable numbers. The mechanisms for such persistence may be complex and depend on a variety of environmental conditions.
In a highly collaborative effort with Dan Doak, Megan Peterson, and Allison Louthan, I studied the demographics of an extremely rare endemic plant, desert yellowhead (Yermo xanthocephalus). This plant has been identified at only two locations--both in central Wyoming. We conducted demographic surveys for five years to assess viability of the Yermo populations and coupled our analyses with longterm census data from the same site to identify population stability. We found that a variety of mechanisms have allowed these populations to persist so far, despite their very low numbers; the longterm census data, collected by Dick and Beverley Scott, was key to identifying these mechanisms. Niche relationships: horned lizards
In Wyoming, the greater short-horned lizard (Phrynosoma hernandesi) is classified as a Species of Greatest Conservation Need based on its vulnerable population status and associated limiting factors. Unfortunately, we have little understanding of what those factors are that most limit the species’ distribution and abundance. Specialist species, like most horned lizards, are generally thought to be at heightened risk in changing landscapes, as they may be increasingly unable to meet their narrow ecological requirements. The most pressing threat at this time is energy development, and we know little about how horned lizards will respond to related land cover changes.
Niche relationships: Frogs
Landscape management schemes can have unanticipated effects on native species. While we tend to label habitat alterations as distinctly good or bad for specific species, it is not always clear what constitutes good habitat and what is low quality habitat. In Ireland, afforested blanket bogs are managed to create a cycle of mature conifer forest alternating with a clear-felled landscape. These plantation forests have the potential to fragment naturally occurring amphibian habitat and reduce access to suitable breeding sites, though it is not clear how each management stage actually affects amphibian populations.
I studied the European Common Frog (Rana temporaria), to identify if parts of these plantations contained good breeding habitat. I conducted my study in the west of Ireland, comparing breeding habitat availability and use among pools in mature plantation forests, clear-felled areas, unplanted blanket bogs, and roadside drainage ditches. |
Coevolution of microbes and host plant circadian clock
Microbes in the rhizosphere, the region of soil that interacts with plant roots, can determine host plant fitness, metabolic activity, and a variety of phenological events. These microbes can also affect circadian period in plants. Soil microbe communities are naturally heterogeneous across fine spatial scales, but may evolve locally with their host plants. coming soon. Variation in soil microbe communities and consequences for plant populations
coming soon. Environmental limits: horned lizards
coming soon. Consequences of spatial patterns: ants
An important but understudied aspect of community structure involves the spatial patterning of species and processes within the landscape. While classic community ecology is, and continues to be, largely founded on non-spatial analyses, we now understand that spatial heterogeneity and patterning is often a critical driver of ecological dynamics. Organisms that self-organize can have highly variable patterning and densities, with corresponding effects on their community functions. The sagebrush steppe and short-grass prairie regions of the intermountain west are shaped by the activities of ecosystem engineers, such as the western harvester ant (Pogonomyrmex occidentalis), that can affect diversity at several scales.
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