Harvard Forest Research

Disentangling Mercury Pollution from Other Ecoregional Threats: An Information Theoretic Approach Applied Across Disturbance Gradients in the Northeastern United States

Principal Investigator: Michael Bank
Harvard School of Public Health: Jun 15 2007 - Dec 31 2010:

Abstract:
Ecoregional conservation targets typically face numerous interacting threats, making it difficult to distinguish the effects of individual threats. This hampers our ability to set priorities, establish policy positions, mobilize resources and partners, or convince policy-makers to address these threats. The threat of atmospheric mercury deposition presents a telling example. The ecological and human health consequences of this widespread pollutant are issues of national and international debate, highlighting a need to distinguish the effects of this threat from others affecting individual species and ecosystem structure and function.
We will collect field data to fill gaps in existing information and use geographic statistics to distinguish the ecological effects of atmospheric mercury pollution from those of other key regional stressors across a gradient of disturbances and physical and biotic conditions in the northeastern United States (Eastern U.S. Conservation Region); the results will include a predictive model of the geographic distribution of ecotoxic risk. Additionally, we will seek support for a regional conference addressing mercury pollution from both environmental and human health perspectives. The resulting information will be essential to:
(1) identify geographic areas, habitats, taxonomic groups, and natural communities at greatest ecotoxic risk from atmospheric mercury deposition;
(2) evaluate the effectiveness of current regulatory policies and potential effectiveness of alternative policies;
(3) build a much needed regional assessment of environmental stressors in the Northeastern U.S.;
(4) establish generalizable practices for disentangling webs of potentially high-priority ecoregional stressors, and baseline information for conservation efforts to investigate the spatial and temporal relationships among suspected stressors.

The proposed salamander sample collections will take place in the Harvard Forest chronic nitrogen amendment plots: 1) control, 2) low N, 3) low N plus sulfur (N+S) and 4) high N. We will collect Plethodon cinereus adults (n = < 5 total from each site for a total of 20 salamanders) using standard hand and dip-net capture methods (Heyer et al. 1994). Spatial coordinates (UTM) of all specimens collected will be provided after field sampling since it is impossible to know the exact locations prior to the collections.

The goal of this investigation is to evaluate the effects of the N-treatments on mercury and other trace metal bioavailability, trophic position (δ15N), and energy flow (δ13C) in Plethodon cinereus.
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