Cascading effects of foundation species

Tree genetics

This work stems from my interest in the impacts of human habitat alteration on population functioning, except in this case the altering species are a tree and a mammal, and the effects are normally ecologically positive. NAU's Cottonwood Ecology Group examines community genetics in Populus systems in the American West, hotspots of biodiversity that are rapidly disappearing, and is one of the main research groups to show that genetic diversity begets biological diversity.

I am interested in how selective foraging by a foundation mammal, the American beaver (Castor canadensis), impacts the genetic diversity and structure of a foundation tree (Populus fremontii), and how this in turn impacts the diversity of dependent arthropod communities, which are important to avian and other fauna. Two recent papers appeared in the journal Forests: Walker et al. 2021 and Durben et al. 2021. I contributed to book chapters regarding forest biodiversity and policy (Wymore et al. 2014) and genetic and genomic insights to community ecology (Alan et al. 2012), and established an experimental garden on Chevelon Creek, Arizona, which will be used to identify Fremont cottonwood trees that are avoided by beavers and that resprout vigorously following beaver-felling, for use in restoration in Arizona and elsewhere. This research garden is part of a riparian restoration project of the Arizona Game & Fish Department, in collaboration with NAU's Tom Whitham.

Bats as foundation species

We are beginning to examine the role of bats as foundation species in caves and mines, where they're the main supplier of nutrients in otherwise nutrient-poor environments. We're coupling our bat DNA mini-barcode with next generation sequencing to examine the web of insect, bacteria, and fungal communities associated with guano. This is a collaboration with Slava Fofanov of NAU.