Rikke KF Jeppesen, PhD
ESNERR Estuarine Ecologist
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**internship opportunities available.
Water quality effects on distribution, abundance, survival, and growth of vertebrate and invertebrate estuarine species. Effects of eutrophication on marsh health. Spatial and temporal variation in native and non-native invertebrate abundance and distribution. Non-native species’ prevention and eradication
Estuarine Restoration Ecology
Optimization of habitat for estuarine species, including saltmarsh inhabitants and intertidal and subtidal species.
Marine invertebrate distributions, abundances, and individual level differences in species between native and invaded ranges.
Rikke has worked on abundance and distribution of intertidal invasive invertebrates and native tidepool fishes.
Dissertation Research: For her dissertation research, Rikke investigated biogeographic variation in invasions of the European green crab, Carcinus maenas.
Rikke’s interests are biogeographic variation in life history traits and species interactions of species with large geographic ranges. More specifically, how does abundance, morphology, and behavior differ between invaded and native ranges of the European green crab, Carcinus maenas? This work also investigates whether behavioral traits and native/non-native crab interactions affect invasion success.
The focus of this research is to develop and compare different indicators of invasion success and characterize variation in these indicators at a biogeographic scale. Long term crab monitoring in Elkhorn Slough, California has shown that while relative abundances of native crabs have been declining since 2001, relative abundance of the European green crab has been increasing. This intriguing pattern has brought to our attention that the invasion success of the European green crab is highly variable in different estuaries and bays.
Many invasive species studies focus on one aspect of the invader or the invaded community, in one area. Instead of this depth of focus, this work aims for breadth, both geographically and in rapid assessment of multiple attributes of the invasive species and the communities it is found in. From the results of this study we will enhance our understanding of the complex ecological interactions that occur after initial invasion and possibly contribute to success or failure of an invader. Consequently, the results of this work will provide coastal and reserve managers with key tools for predicting invasion patterns and identifying areas vulnerable to invasion.
Senior Thesis Research: For her senior thesis, Rikke worked on settlement rates of three species of intertidal sculpins, in collaboration with Amy Ritter.
In collaboration with Amy Ritter, Rikke worked on daily settlement of three species of intertidal sculpins, Clinocottus globiceps, C. recalvus and Oligocottus snider. The focus of this research was to investigate the relative importance of settlement and post-settlement processes, in determining intertidal sculpin species assemblage and community structure. Rikke worked on quantifying daily, and bi-daily settlement rates of intertidal sculpins, in order to determine whether monthly recruitment was a good proxy for settlement rates.
Rikke currently works on various projects, all related to the relationships between organisms and water quality.
One of the current projects is investigating how water quality affects growth and survival of common estuarine species. More specifically, we investigated how extended and frequent periods of low dissolved oxygen affects fish- and oyster growth and survival in the estuary.
Another project is exploring the effect of eutrophication on marsh plants. More specifically, we looked at how blooms of floating algae leads to deposition of algal mats on the marsh which then affects growth and survival of the most common marsh plant, pickleweed at Elkhorn Slough.
Last, Rikke is involved in project management restoring a substantial area of salt marsh at Elkhorn Slough. The restoration process is informed by research and monitoring at Elkhorn Slough and at similar habitats in the area, in order to obtain the best design and managements of restored habitat.
Opportunities for interns
Rikke frequently works with local, national, and international student interns. In the past two years, she has worked with interns from local colleges such as Hartnell College, Salinas; California State University, Monterey Bay, and UC Santa Cruz. She has also worked with interns through NOAA, and NSF (REU, Research Experience for Undergraduates). If you are interested in an internship, contact Rikke at email@example.com
Preisler RK, Wasson K, Wolff WJ, Tyrrell MC. 2008. Invasions of estuaries versus the adjacent open coast: A global perspective. In: Marine Bioinvasions: Ecology, Conservation and Management Perspectives [Book]. Editors: Gil Rilov and Jeff Crooks. Springer, Berlin , Germany. Pp.
Ritter AF, Wasson K, Lonhart SI, Preisler RK, Woolfolk A, Griffith KA, Connors S, Heiman K. 2008. Ecological signatures of anthropogenic alteration of tidal exchange in estuarine ecosystems. Estuaries and Coasts 31(3):554-571
Ritter AF, Preisler RK. 2006. Spatial variation in the structure of an intertidal fish assemblage reflects daily settlement patterns. Marine Ecology Progress Series 317:211-223