Monday, October 10, 2016

American Dipper

Understanding long-term trends in Se and Hg exposure and effects in an aquatic songbird, the American Dipper (Cinclus mexicanus).

In 1990s and early 2000s, research by Environment and Climate Change Canada (ECCC) in collaboration with SFU, utilized the American Dipper as an excellent water quality indicator to establish a valuable long term database that is an ideal resource for current CEAA assessments on specific locations throughout BC. In 2014-2015, the impacts of Run of the River (ROR) hydroelectric generation was evaluated by studying American Dipper at ROR sites in Whistler- Pemberton. Although ROR sites have a small reservoir and water holding time is about 48 hours, Dippers are attracted to the reservoirs, and there is some evidence of fewer hatch year birds at the ROR streams. Stable isotopes in the birds and food web indicate sulphate reducing bacteria are present with potential methylation of mercury, and at one site the Hg levels in American Dippers exceeded levels that are considered health risks for songbirds. In 2016-2017, a new graduate student with UBC (Kathy Martin/Bishop supervisors) will examine Se/Hg contamination in the Elk Valley/Kootenays and its effects on American Dippers and other aquatic birds where multiple coal mines now exist. This study will compare results in American Dippers to a study in 2002-2003 at the same study sites, some of which were sampled pre mine construction.  Notably, the Se levels in the water in the Elk River have increased 5 x above the levels when the earlier study was conducted.

A uniquely banded America Dipper




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