What We Do

Spring Rivers specializes in integrated assessment of biological and physical factors that affect ecosystem function and health. We have extensive experience with surveys of rare and special-status species and have employed our knowledge of aquatic ecosystems in the design of ecologically appropriate remediation. ​

Spring Rivers is headquartered in the Burney/Fall River Region of northeastern California. We are situated at the edge of the Modoc Plateau and the intersection of the Cascade and Sierra Nevada mountain ranges. The unique combination of geological and hydrological conditions of the region have created an extensive system of large freshwater springs surrounded by majestic mountains to the south and west and a dry lava plateau to the north and east. The area is ecologically diverse and is home to a large number of endemic native aquatic species.  


 Maria J. Ellis, PhD
Maria has a doctorate in Aquatic Ecology from the Department of Biology at the University of Michigan, Ann Arbor, and a master’s degree in Marine Science from the University of South Carolina, Columbia. Maria first came to the Intermountain Area of northeastern California in 1990 and has been studying the ecology of aquatic species in northeastern California ever since. Maria is an expert on the federally and state-listed endangered Shasta crayfish. She wrote the draft recovery plan for CDFG and assisted USFWS in the preparation of the final recovery plan for the Shasta crayfish, which was approved in 1998. 

 Jeffrey D. Cook
Jeff has a bachelor’s degree in Conservation and Resource Studies from the University of California, Berkeley and more than two decades of consulting experience studying aquatic ecology and geomorphology of rivers and streams. He has extensive experience in both fields and has worked throughout California, as well as in Oregon, Washington, Montana, and Georgia. Jeff worked out of the San Francisco Bay Area for EA Engineering and Stillwater Sciences before moving to northeastern California in 1995 to work with Maria in the business that would become Spring Rivers Ecological Sciences. 

The Crew

Koen G. H. Breedveld
Koen is an entomologist and aquatic ecologist with a Master’s degree in Entomology from Washington State University, Pullman, and a Bachelor’s degree in Biological Sciences from California State University, Chico. Koen came to Burney in 2003 and has been studying the ecology of aquatic species in northeastern California since. Koen’s special focus is studying the demographics of the foothill yellow-legged frog population in the Pit River. His other research interests include other amphibians, aquatic insects, the endangered Shasta crayfish, aquatic and terrestrial molluscs, and medium to large-size carnivores. 

Lorrie E. Haley

Lorrie is a fisheries biologist and aquatic ecologist with a Master’s degree in Fisheries Resources from University of Idaho and a Bachelor’s degree in Animal Science from UC Davis.  Lorrie was born and raised in Burney California and moved back to her hometown in 2004 to join Spring Rivers.  She currently specializes in freshwater mollusc and terrestrial mollusc ecology. 

Mark L. Stalcup

Mark is an aquatic ecologist with a Bachelor’s degree in Fisheries from Humboldt State University, Arcata.  Mark came to the Intermountain area in 2003 and has been with Spring Rivers Ecological Sciences since.  His focus project has been the Western Pond turtle populations in the Pit River, and its tributary creeks.  Mark has also been involved in most other Spring Rivers research projects, particularly foothill yellow-legged frogs and the endangered Shasta crayfish.  

Steven M. Breth

Steve is a biologist with a Bachelor's degree in Wildlife Biology from Colorado State University, Colorado.  Steve moved to California in 2002 to work for the USDA Forest Service and MGW Biological, surveying for the northern goshawk and california spotted owl.  He joined Spring Rivers in 2010, participating in foothill yellow-legged frog, endangered Shasta crayfish, aquatic and terrestrial mollusc surveys.

Lauren A. Bridgeman

Lauren is a biologist with Bachelor's degrees in Zoology and Marine Biology from Humboldt State University, Arcata.  Lauren joined Spring Rivers in 2011, participating in foothill yellow- legged frog, endangered Shasta crayfish, aquatic and terrestrial mollusc surveys.