who we are

Dr. Rebecca J. Best

Assistant Professor


Google Scholar

I am an aquatic community and evolutionary ecologist interested in the processes that determine the number and type of species we find coexisting in a particular community, and the way those communities function. My lab works on the effects of climate on aquatic connectivity, species distributions, and the ecology and evolution of riparian tree traits.

Dr. Hillary F. Cooper

Postdoctoral Researcher


Google Scholar

I am an evolutionary ecologist interested in how organisms can respond to environmental stress via genetic or plastic mechanisms. As a post-doc in THE BEST lab and the Cottonwood Ecology Group, I will be studying the evolution and ecological consequences of phenotypic plasticity to climate change and insect herbivory in cottonwood trees, and how it may then affect communities of dependent organisms. I earned a PhD in Biology at NAU in 2018 researching genetic and trait variation in cottonwoods.

Graduate students

Iris Garthwaite (MS Environmental Sciences and Policy)

Iris joins the lab from Evergreen State where she worked with Dr. Carri LeRoy and started building her science twitter reach! Iris brings substantial experience with the growth and decomposition of riparian plants, and will be working on trait plasticity in collaboration with the Cottonwood Ecology Group.

Eric Frye (MS Environmental Sciences and Policy)

Eric is working with Rebecca and David Ward at the USGS on ways to control invasive fish in aquatic habitats of Arizona.

Lindsay Hansen (MS Environmental Sciences and Policy)

Lindsay is studying the increasing abundance of a native fish (the flannelmouth sucker) in the Colorado River by modeling growth rates in response to changing water temperature in the Grand Canyon. She is co-advised with Brett Dickson and collaborating with Charles Yackulic at the USGS GCMRC.

Undergraduate students

Dylan Chandler

As a NASA Space Grant intern, Dylan investigated the use of eDNA as a tool for aquatic biodiversity monitoring across a temperature gradient. Dylan is completing both a BS in Environmental Sciences and an MS is Climate Sciences and Solutions through the 4+1 program.

Yazhmin Dozal

Yazhmin is completing her BS in Environmental Science with a Minor in Biology and a certificate in Ecology and Wildlife Management. She is working on pond invertebrate community diversity for her senior research project. Yazhmin is also Co-Chair of the NAU Green Fund Committee and an active member of The Wildlife Society’s NAU chapter.

Catherine Lepp

Catherine is a double major in Geology and Biology. As a Hooper Undergraduate Research Award recipient, she is working on genetic and environmental effects on cottonwood leaf traits in collaboration with the Cottonwood Ecology Group.

Joshua Rihs

Joshua is completing his BS in Environmental Sciences with a minor in GIS. As a 2x Hooper Undergraduate Research Award recipient, he has already worked on the impact of transgenerational plasticity on the growth and reproduction of native and introduced amphipods, and is now working on the recovery of pond invertebrate communities following extreme drought.

Matthew Johnson

As a Hooper Undergraduate Research Award recipient, Matthew is working on understanding trait variation in aquatic insect larvae, and how multiple environmental tolerance traits have evolved across orders and families.

Lab alumni

Joann Jeplawy (MS Environmental Sciences and Policy)

Now at: Tetra Tech, Denver, CO. In collaboration with the Cottonwood Ecology Group, Joann studied the impacts of leaf plasticity on aquatic community composition in cottonwood leaf litter from three common gardens in Arizona and Utah.

Kaitlin Haase (MS Environmental Sciences and Policy)

Now at: Xerces Society for Invertebrate Conservation. Kaitlin studied the biodiversity and connectivity of natural and anthropogenic ponds across northern Arizona in relation to aquatic habitat loss due to climate change.

Sarah Sterner (MS Environmental Sciences and Policy)

Now at: USGS, Flagstaff AZ. Sarah worked with Rebecca Best, Clare Aslan, and the Landscape Conservation Initiative to study the impacts of land management policies on ecosystems across boundary lines between federal, regional, and state owned lands.

Morgan Andrews (BS Environmental Sciences)

Now at: USGS. As a Hooper Undergraduate Research Award recipient, Morgan worked on the effects of water temperature on the distribution of aquatic biodiversity across ponds in Arizona, using both field and lab approaches. She was awarded the Best Poster in Applied Research at the 2019 Society for Freshwater Sciences meeting in Salt Lake City, Utah!

Kaitlen Bieber (BA Environmental & Sustainability Studies)

Kaitlen helped launch the lab’s stock pond biodiversity work before spending her third year studying abroad at UNAM (Universidad National Autonomous de Mexico) in Mexico City. She is currently working on picking the perfect graduate program!

Lauren Mason-Sarantopulos (BS Environmental Sciences)

Now at: USGS. As a 2x Hooper Undergraduate Research Award recipient, Lauren created and carried out two independent research projects on the effects of temperature and nitrates on native vs. introduced amphipods in Arizona, both within and across generations.

Madelyn Norstrem (BS Environmental Sciences)

Now at: Peace Corps. Madelyn worked as an NSF REU student to help lead the lab’s study of herbivory and climate change impacts on cottonwood trees. She also worked as an Interns to Scholars student studying aquatic invertebrate communities.

Joe Sweet (BS Environmental Sciences)

As a NASA Space Grant intern, Joe worked on using remote sensing to detect the presence of water in ponds across the northern Arizona landscape, giving us much greater spatial and temporal information on habitat availability.