who we are

Dr. Rebecca J. Best

Associate Professor

Google Scholar

I am an aquatic community and evolutionary ecologist interested in the processes that determine the distribution and consequences of genetic and functional diversity within and among species. My lab works on the effects of climate on community and population connectivity in aquatic invertebrates, the ecology and evolution of riparian tree traits, and aquatic conservation.


Dr. Hillary F. Cooper

Postdoctoral Researcher

Google Scholar

Hillary is an evolutionary ecologist interested in how organisms can respond to environmental stress via genetic or plastic mechanisms. As a post-doc in the Cottonwood Ecology Group, Hillary studies 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. Hillary earned her PhD in Biology at NAU in 2018 researching genetic and trait variation in cottonwoods.

Jackie Corbin

PhD in Biological Sciences

Jackie is co-advised with Dr. Tom Whitham in the Cottonwood Ecology Group. She is testing how leaf spectroscopy methods can efficiently detect genetic and environmental variation in plant leaf traits, and their ecological consequences.

Iris Garthwaite

MS Environmental Sciences and Policy, now PhD Earth and Environmental Sciences

Iris joined the lab from Evergreen State where she worked with Dr. Carri LeRoy and started building her science twitter reach! Iris works on trait plasticity in collaboration with the Cottonwood Ecology Group.

Yazhmin Dozal

MS Environmental Sciences and Policy

Yazhmin is completing her MS as a Fellow with the RISE Program for Environmental Health research, and is studying the relationship between changing aquatic environments, the distribution of mosquito larvae, and disease. Previously, Yazhmin graduated as the Distinguished Senior for the College of the Environment, Forestry, and Natural Sciences at NAU. She was Co-Chair of the NAU Green Fund Committee and an active member of The Wildlife Society’s NAU chapter.

Susan Wood

MS Environmental Sciences and Policy

Susan is working on the control of invasive crayfish species in Arizona, in collaboration with David Ward at the USGS and with funding and input from the US FWS Southwest Non-Native Aquatic Species Community of Practice.

Joshua Rihs

MS Environmental Sciences and Policy

Joshua completed his BS in Environmental Sciences and was the School of Earth and Sustainability’s Outstanding Senior in 2022. 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.


Lab alumni


Joann Jeplawy

MS Environmental Sciences and Policy

Now at: Environmental Protection Agency, 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. Her MS research is published in Ecology.

Kaitlin Haase

MS Environmental Sciences and Policy

Now at: Xerces Society for Invertebrate Conservation, Santa Fe, NM. 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. Sarah was co-advised with Clare Aslan, and worked with the Landscape Conservation Initiative to study the impacts of land management policies on ecosystems across boundary lines between federal, regional, and state owned lands. Her MS research is published in Forest Ecology and Management.

Lindsay Hansen

MS Environmental Sciences and Policy

Now at: USGS, Flagstaff, AZ. Lindsay studied 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 was co-advised with Brett Dickson and in collaboration Charles Yackulic. Lindsay has also published a children’s book about her research!

Catherine Lepp

BS Environmental Sciences

As a Hooper Undergraduate Research Award recipient, Catherine worked on genetic and environmental effects on cottonwood leaf traits in collaboration with the Cottonwood Ecology Group.

Dylan Chandler

BS Environmental Sciences and MS Climate Sciences and Solutions

As a NASA Space Grant intern, Dylan investigated the use of eDNA as a tool for aquatic biodiversity monitoring across a temperature gradient.

Matthew Johnson

BS Biology

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

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: AZGF. 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

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.