Determining optimal sampling strategies for monitoring mercury and reproductive success in common loons in the Adirondacks of New York
- 44 Downloads
The common loon (Gavia immer), a top predator in the freshwater food web, has been recognized as an important bioindicator of aquatic mercury (Hg) pollution. Because capturing loons can be difficult, statistical approaches are needed to evaluate the efficiency of Hg monitoring. Using data from 1998 to 2016 collected in New York’s Adirondack Park, we calculated the power to detect temporal changes in loon Hg concentrations and fledging success as a function of sampling intensity. There is a tradeoff between the number of lakes per year and the number of years needed to detect a particular rate of change. For example, a 5% year−1 change in Hg concentration could be detected with a sampling effort of either 15 lakes per year for 10 years, or 5 lakes per year for 15 years, given two loons sampled per lake per year. A 2% year−1 change in fledging success could be detected with a sampling effort of either 40 lakes per year for 15 years, or 30 lakes per year for 20 years. We found that more acidic lakes required greater sampling intensity than less acidic lakes for monitoring Hg concentrations but not for fledging success. Power analysis provides a means to optimize the sampling designs for monitoring loon Hg concentrations and reproductive success. This approach is applicable to other monitoring schemes where cost is an issue.
KeywordsPower analysis Sampling guidance Mercury Fledging success Bioindicator Common loon Lake acidity Adirondack Park
We greatly appreciate the many hours the Adirondack field crew has devoted each summer to document the return rate and reproductive success of the color-banded study loons. The Adirondack Watershed Institute of Paul Smith’s College and the Adirondack Ecological Center of SUNY ESF generously provided students annually to assist with monitoring the banded loons on some of our study lakes. The staff of the New York State Department of Environmental Conservation, the Wildlife Conservation Society’s Zoological Health Program, and Calvin College have provided in-kind staff support and equipment for the loon capture and sampling fieldwork each year.
Financial support was provided by the New York State Energy Research and Development Authority, the Wildlife Conservation Society, The Wild Center, the Raquette River Advisory Council, and numerous private foundations and donors.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable national, and institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution at which the studies were conducted.
- Barkay T, Gillman M, Turner RR (1997) Effects of dissolved organic carbon and salinity on bioavailability of mercury. Appl Environ Microbiol 63:4267–4271Google Scholar
- Barr JF (1986) Population dynamics of the Common Loon (Gavia immer) associated with mercury-contaminated waters in northwestern Ontario. Environment Canada, Canadian Wildlife Service 56:25Google Scholar
- Buxton VL, Evers DC, Schoch N (2019) The influence of biotic and abiotic factors on banded common loon (Gavia immer) reproductive success in a remote, mountainous region of the northeastern United States. EcotoxicologyGoogle Scholar
- Champoux L, Masse DC, Evers D, Lane OP, Plante M, Timmermans ST (2006) Assessment of mercury exposure and potential effects on common loons (Gavia immer) in Québec. In: Limnology and aquatic birds . Springer, Dordrecht, pp 263–274Google Scholar
- Evers DC (2001) Common loon population studies: continental mercury patterns and breeding territory philopatry. Ph.D. Dissertation, University of Minnesota, St. Paul, MNGoogle Scholar
- Evers DC (2004). Status assessment and conservation plan for the Common Loon (Gavia Nimmer) in North America. US Fish and Wildlife Service, Hadley, MAGoogle Scholar
- Götmark F (1992) The effects of investigator disturbance on nesting birds. In Current ornithology. Springer, Boston, MA, pp 63–104.Google Scholar
- Hake M, Dahlgren T, Ahlund M, Lindberg P, Eriksson MO (2005) The impact of water level fluctuation on the breeding success of the Black-throated Diver Gavia arctica in South-west Sweden. Ornis Fennica 82:1–2Google Scholar
- Nelson GA (2015). Fishmethods: fishery science methods and models in R. R package version 1.7–0. http://cran.r-project.org/web/packages/fishmethods/index.html
- Ream CH (1976) Loon productivity, human disturbance, and pesticide residues in northern Minnesota. Wilson Bull 88(3):427–432Google Scholar
- Schoch N, Glennon M, Evers D, Duron M, Jackson A, Driscoll C, Yu X, Simonin H (2011) Long-term monitoring and assessment of mercury based on integrated sampling efforts using the common loon, prey fish, water, and sediment NYSERDA Rep No 12-06:116. https://www.nyserda.ny.gov/About/Publications/Research-and-Development-Technical-Reports/Environmental-Research-and-Development-Technical-Reports#eco. Accessed 25 Jan 2017
- Schoch N, Glennon MJ, Evers DC, Duron M, Jackson AK, Driscoll CT, Ozard JW, Sauer AK (2014) The impact of mercury exposure on the Common Loon (Gavia immer) population in the Adirondack Park. Waterbirds, New York, USA, pp 133–146. 37Google Scholar
- Schoch N, Yang Y, Yanai RD, Buxton VL, Evers DE, Driscoll CT (2019) Spatial patterns and temporal trends in mercury concentrations in common loons (Gavia immer) from 1998 to 2016 in New York’s Adirondack Park: has this top predator benefitted from mercury emission controls? EcotoxicologyGoogle Scholar
- U.S. Environmental Protection Agency (2007) Mercury in solids and solutions by thermal decomposition, amalgamation, and atomic absorption spectrophotometry. U.S. Environmental Protection Agency, EPA-7473. 17ppGoogle Scholar
- Weeber RC (1999) Temporal patterns in breeding success of Common Loons in Ontario, 1981–1997. Final report. Bird Studies Canada to Environment Canada, Gatineau, Quebec, CanadaGoogle Scholar
- Wolfe MF, Atkeson T, Bowerman W, Burger J, Evers DC, Murray MW, Zillioux E (2007) Wildlife indicators. In: Harris R, Krabbenhoft DP, Mason R, Murray MW, Reash R, Saltman T (eds) Ecosystem responses to mercury contamination: Indicators of change. Webster, NY: CRC Press, pp 134–200Google Scholar