Scientists & Staff

Dr. Anne Timm with oysters on the Chesapeake Bay

Anne Timm

Research Aquatic Ecologist
5523 Research Park Drive; Suite 350
Suite 350
Baltimore, MD, 21228
Phone: 443-543-5385

Contact Anne Timm

Current Research

The scientist's research program investigates how human infrastructure development, land cover change, restoration activities, and land or water management affect structure and function of aquatic ecosystems. This work requires applied, multi-scale, interdisciplinary approaches to investigate changes to aquatic and riparian ecosystems and response of aquatic species over time. Dr. Timm's current research projects include a collaborative study with University of Maryland, Baltimore County that quantifies bioaccumulation of contaminants of emerging concern (CECs), including hormones, UV-filters from sunscreens, and antibiotics, in crayfish of urban streams and oysters of the Chesapeake Bay. The scientist is also working on a collaborative project with Stroud Water Research Center to develop a model that quantifies effects of land cover change on stream temperature.

Detection of estrogenic chemicals and UV-filters in aquatic and coastal invertebrates

The appearance of estrogenic hormones, UV filters, and antibiotics in the environment has drawn increasing attention due to potential impacts on human and ecological health. Potential sources of estrogenic hormones and antibiotics include wastewater treatment effluents and animal feeding operations. One objective of this collaborative research study with University of Maryland, Baltimore County was to measure five UV-filters and three estrogenic hormones in virile crayfish (Orconectes virilis) tissue to better understand CEC occurrence in urban streams. By applying a novel extraction procedure and liquid chromatography tandem mass spectrometry analysis, we simultaneously detected 6 CECs. The 4-methylbenzylidene camphor (75-352 ng/g), octocrylene (3-113 ng/g), and homosalate (78-399 ng/g) UV-filters were present in all crayfish samples. In addition, the UV-filters, oxybenzone and ethylhexyl-methoxycinnamate were detected at concentrations as high as 51 and 83 ng/g, respectively. The synthetic estrogen, 17-ethinylestradiol, was also present in crayfish tissue at one site at concentrations of 17 ng/g. A second objective was to apply these methods to other aquatic and coastal invertebrates from multiple habitats. As a result of applying these methods to tissue samples from virile crayfish, red swamp crayfish (Procambarus clarkii), eastern oyster (Crassostrea virginica), and hooked mussel (Ischadium recurvum), all five UV-filters and all three estrogenic hormones were detected at least once. The highest concentration of all CECs detected was 399 ng/g of homosalate in virile crayfish from an urban stream. These results highlight the ubiquitous bioaccumulation of CECs in aquatic and marine invertebrates.

Riparian forest management effects on aquatic habitat connectivity

Increased urban land use in watersheds is known to affect aquatic species distributions and aquatic habitat connectivity. In urbanized watersheds, engineered infrastructure can result in excessive stormwater runoff, lower groundwater levels, and increased stream temperatures. I am working with scientists at Stroud Water Research Center and University of Birmingham, UK to develop a geospatial statistical model that incorporates high resolution land cover data, soil, elevation, flow, and on-the-ground stream temperature logger data to identify and map thermally suitable habitat for aquatic species. This research will identify differences in how much riparian buffer width and length are needed in relation to urban and agricultural land cover categories and temperature tolerance limits of aquatic species. Results will be applied to riparian buffer restoration to maintain or restore stream temperatures needed to maintain native coldwater stream communities.

Research Interests

  • Urban land cover change effects on stream and riparian ecosystem structure and function

  • Using bioindicator species to detect effects of wastewater treatment on aquatic ecosystems

  • Stream simulation design effectiveness for maintaining aquatic organism passage

  • Population genetic approaches at the landscape scale for aquatic species management

  • Effects of water level change and hydrological modification on aquatic communities

Past Research

Quantifying fish habitat associated with stream simulation design culverts

This study investigated the effects of culvert replacement design on fish habitat and fish weight by comparing substrate diversity and weight at three stream simulation (SS)-design and three bankfull and backwater (BB)-design sites on the Chequamegon-Nicolet National Forest, Wisconsin. Stream channel cross-sections, Wolman substrate particle counts, and single-pass backpack electro-fishing survey data were used to quantify fish habitat and fish weight in 50-m upstream and downstream sample reaches at each site. We applied generalized linear mixed models to test the hypothesis that substrate size and fish weight did not differ according to stream-crossing design type (SS or BB) and location (upstream or downstream). Substrate particle sizes were significantly greater upstream of the stream crossing when compared to downstream of the stream crossing at both SS and BB sites for riffles and pools. Substrate particle sizes were also significantly greater upstream of BB sites when compared to upstream of SS sites. Results of this study indicated statistically greater individual fish weights upstream of SS-design sites in comparison to upstream of BB-design sites in first- to third-order low gradient streams. These results suggested that the SS-design approach appears to be more effective at transporting sediment downstream, and illustrated the value of using fish weight as an indicator of biological success for stream-crossing designs.

Water level change effects on northern pike spawning success in large, regulated reservoirs

Northern pike are a useful indicator species for water level change because spring flooding triggers spawning, and water levels during and following spawning will determine productivity of the larval and young-of-the-year (YOY) life stages. This project investigates how timing of water level change in regulated border waters of the Minnesota, United States and Ontario, Canada may affect northern pike spawning success and littoral zone aquatic plant community structure. Quatrefoil light traps fished at night were used to sample larval northern pike in 11 potential nursery areas. Larval northern pike were most commonly sampled among floating-leaf burreed Sparganium fluctuans, common burreed Sparganium eurycarpum, sedges Carex spp., hybrid cattail Typha × glauca and wild rice Zizania palustris. A negative binomial model of light-trap catches using the presence/absence data for 2012 from all 11 bays included water elevation and the presence of cattail as significant variables. Ultimately, the species of vegetation may not be as important as the physical quality or form of the vegetation in supplying feeding and hiding cover. The aquatic plant species and structural forms encountered by larval northern pike suggest they use nearly any vegetated cover available in early spring. Water-level regulations that change availability of aquatic vegetation are likely to influence recruitment of northern pike to larger sizes. Olson, J.C.; Marcarelli, A.M.; Timm, A.L.; Eggert, S.L.; Kolka, R.K. 2017. Evaluating the Effects of Culvert Designs on Ecosystem Processes in Northern Wisconsin Streams. River Research and Applications. 33(5): 777-787.

Why This Research is Important

Detection of estrogenic chemicals and UV-filters in aquatic and coastal invertebrates

Contaminants of emerging concern (CECs), including estrogenic hormones and pharmaceuticals, are being documented in surface waters throughout the United States and the world at a growing rate. In urbanized watersheds, streams, ponds, and wetlands are connected to the land through highly engineered drainage networks and sewer pipes, resulting in decreased water quality and increased bioaccumulation of toxic chemicals in aquatic organisms. Specific CECs are only found in wastewater effluent, such as UV-filters, and others are only found in runoff from animal feeding operations (veterinary-only antibiotics). Therefore, detection of bioaccumulation of these specific CECs in aquatic and coastal species can be applied to indicate potential pollutant sources in urban and agricultural landscapes.

Riparian forest management effects on aquatic habitat connectivity

Climate change and urbanization will both influence intensity of flow, storm event frequency, water temperature, and composition of riparian vegetative communities. This work will result in a riparian restoration prioritization tool that can be applied at multiple spatial scales, according to the likelihood of a habitat patch changing from coldwater to coolwater thermal classes for fish. Water temperature increases may result in loss of coldwater habitat and extirpation of species that need colder water to survive, grow, and reproduce. The model and prioritization tool developed as a part of this project can be reapplied, using various climate and urban land use change scenarios to identify coldwater habitat patches that are most likely to disappear.

Quantifying fish habitat associated with stream simulation design culverts

Removing barriers to movement of aquatic organisms is a type of restoration that has potential to improve extensive amounts of instream habitat. Quantifying the effectiveness of such restoration techniques is often measured in stream length and does not quantify aquatic habitat structural and functional quality. However, habitat quality will determine the likelihood of aquatic species populations persisting over time. This research attempts to quantify stream crossing design effectiveness by comparing structural and functional metrics at stream simulation design sites and bankfull and backwater design sites. Therefore, managers will be able to compare the benefits to costs of these stream crossing designs.

Water level change effects on northern pike spawning success

Water level changes in aquatic habitats are known to affect aquatic species populations and spawning success of fish, and are likely to increase on a broader scale as a result of climate change and increased urbanization. Results of this research were used to inform managers about tradeoffs between regulated water levels and fish spawning success. Results of this research also identified necessary characteristics of the littoral zone aquatic plant community for more productive northern pike early life stage habitat.


  • Virginia Polytechnic Institute and State University, Ph.D. Fisheries and Wildlife, 2011
  • Indiana University, Environmental Science Aquatic Habitat Analysis Environmental Science, Aquatic Habitats, 2000
  • Luther College, B.A. Biology, 1996

Professional Experience

  • Aquatic Ecologist, USDA Forest Service, Hoosier National Forest, Tell City, Indiana 2002 - 2005
  • Environmental Scientist, Hayes, Seay, Mattern, and Mattern, Inc., Raleigh, North Carolina 2000 - 2002
  • Secondary Education Science and Biology Teacher, United States Peace Corps 1994 - 1996

Professional Organizations

  • Society Of Freshwater Science (2015 - Current)
  • American Fisheries Society (2006 - 2014)

Awards & Recognition

  • Service award, 2017 USDA Forest Service, 15 years of service
  • USDA Forest Service, Civil Rights Outstanding Location Award, 2013 NRS-07, Grand Rapids, Minnesota office won for work with Great Lakes Tribal Nations
  • Service award, 2012 USDA Forest Service, 10 years of service award
  • Performance, 2011 USFS,Northern Research Station, superior performance award
  • Performance, 2011 USFS, Northern Research Station, individual cash award for performance
  • Performance, 2010 USFS, Northern Research Station, individual cash award for performance
  • Performance, 2009 USFS, Northern Research Station, outstanding performance award
  • Research Award, 2009 Virginia Tech, Graduate Student Organization Research Award
  • Scholarship, 2007 Virginia Tech, Richard Hunter Cross, Jr. Scholarship

Featured Publications & Products

Publications & Products

Other Publications

He, Ke., A. Timm, and L. Blaney 2017. Simultaneous determination of UV-filters and estrogens in aquatic invertebrates by modified, quick, easy, cheap, effective, rugged, and safe extraction and liquid chromatography tandem mass spectrometry. Journal of Chromatography A 1509: 91-101.

 Olson, J.C., Marcarelli, A.M., Timm, A.L., Eggert, S.L., and Kolka, R.K. 2017. Evaluating the effects of culvert designs on ecosystem processes in northern Wisconsin streams. River Research and Applications 33: 777-787. DOI: 10.1002/rra.3121.

 Timm, A., Higgins, D., Stanovick, J., Kolka, R., and Eggert, S. 2017. Quantifying fish habitat associated with stream simulation design culverts in northern Wisconsin. River Research and Applications 33: 567-577. DOI :10.1002/rra.3117.

Timm, A., E. Hallerman, C.A. Dolloff, M. Hudy, and R. Kolka. 2016. Identification of a barrier height threshold where brook trout population genetic diversity, differentiation, and relatedness are affected. Environmental Biology of Fishes 99: 195-208.

 Timm, A. and R. Pierce. 2015. Vegetative substrates used by larval northern pike in Rainy Lake and Namakan Reservoir. Ecology of Freshwater Fish 24(2): 225-233.

Last modified: Friday, March 16, 2018