Mercury Bioaccumulation within Terrestrial Foodwebs in the Adirondack Park of New York State Amy Sauer 1 , Charles Driscoll 1 , David Evers 2 , Carrie Osborne 2 , Allyson Jackson 2 1 Syracuse University, 2 BioDiversity Research Institute
Appalachian Mountain Mercury Network Partnering agencies and organizations to gain a better understanding of atmospheric deposition and impacts of pollution on forested ecosystems using thrushes and other songbirds as indicators All Photos by Permission or http://common-wikimedia.org
Wildlife Studies Detrimental impacts have been documented in studies relating to amphibian and songbird communities in the Northeastern United States. (Bank et al. 2005, 2006, 2007, Evers et al. 2005, Rimmer et al. 2005)
Pathways for Bioaccumulation Seasonally, songbirds are able to reduce the concentrations of mercury in their bodies through feather growth and egg deposition With continued ingestion of prey species high in mercury content, individuals may accumulate mercury faster than they can rid their bodies of it through natural processes
Indicator Species for Terrestrial Ecosystems Red-eyed Vireo Lincoln’s Sparrow Hermit Thrush Palm Warbler Insectivores are widespread across the landscape ~ necessary to understand the role that these species may represent in regards to the health of the surrounding environment
Indicator Species for Terrestrial Ecosystems • Regional efforts conducted by BioDiversity Research Institute to assess the impacts of Hg on songbird species across 5 terrestrial ecosystems • Each system has an indicator species that best represents the mercury risk in that particular habitat ~ identify at-risk species and sensitive habitats Source: Hidden Risks, BRI 2011
Indicator Species for Terrestrial Ecosystems 30% Reduction in nesting success 20% 10% Source: Hidden Risks, BRI 2011
Methylmercury Bioaccumulation within Montane, Terrestrial Foodwebs Do mercury concentrations in songbirds and invertebrate, prey species change • with respect to elevation, aspect and seasonal variation in high-elevation, terrestrial foodwebs on Whiteface Mountain? • Mercury deposition 2-5x higher in high-elevation, boreal forests as compared to surrounding low-elevation, hardwood forests ~Miller et al. 2005
Methylmercury Bioaccumulation within Montane, Terrestrial Foodwebs STUDY SITES 2009-2010 13 Study Sites Between 450 m – 1400 m
STUDY DESIGN Bicknell’s Thrush HIGH ~ ALPINE ZONE ~ 1300 meters Swainson’s Thrush MID ~ CONIFEROUS ~ 800 meters Balsam Fir/Red Spruce/Paper Birch Hermit Thrush LOW ~ HARDWOOD ~ 450 meters Beech/Birch/Maple TEMPORAL PATTERNS BIOTIC SAMPLES ASPECT Early Summer (early -June) Thrush Family East vs. West Mid Summer (early-July) Invertebrates Late Summer (early-August)
Elevation Patterns – Mercury Exposure in Thrush Species Whiteface Mountain: 2009 - 2010 Sharp-Shinned Hawk Bicknell’s Thrush 2009 - 1.723 ppm Coniferous/ (0.094 ppm) Alpine – 2010 – 1.121 ppm High Elevation Red-Tailed Hawk (Captive) Swainson’s Thrush (0.089 ppm) 2011 - 0.041 ppm (0.085 ppm) Bicknell’s Thrush (0.088 ppm) Swainson’s Thrush Coniferous – (0.120 ppm) Mid Elevation ( 0.109 ppm) Hermit Thrush (0.107 ppm) Hermit Thrush (0.063 ppm) Hardwood – Within-site Low Elevation Blood Hg Levels Swainson’s Thrush (0.068 ppm) (0.081 ppm)
Aspect Patterns- Mercury Exposure in Boreal Songbird Species : Mercury concentrations were higher for all species sampled on the West side of Whiteface mountain, with the exception of Red-eyed Vireo, Bicknell’s Thrush and White-throated Sparrow. Blood Mercury Values (ppm) for Songbird Species on East and West Side of Whiteface Mountain: 2009-2010 0.2 0.18 0.16 Mean Blood Mercury (ppm, ww) 0.14 0.12 0.1 East 0.08 West 0.06 0.04 0.02 0 White-throated Slate-colored Ovenbird Blackpoll Hermit Thrush Bicknell's Swainson's Red-eyed Blue-headed Sparrow (n=24, Junco (n=18, (n=23, 11) Warbler (n=1, (n=21, 10) Thrush (n=16, Thrush (n=19, Vireo (n=11, Vireo (n=1, 1) 7) 17) 2) 7) 23) 11) Species
Seasonal Patterns - Mercury Exposure in Boreal, Forest Species : Bicknell’s and Hermit Thrush show a decrease in Hg concentrations during the field season, while Swainson’s Thrush shows a slight increase. Blood Mercury Values (ppm) for Boreal Songbird Species on Whiteface Mountain: 2009- 2010. 0.25 0.2 Bicknell's Thrush Mean Blood Mercury (ppm, ww) y = -0.0003x + 0.1426 R² = 0.0147 0.15 Hermit Thrush y = -8E-05x + 0.0784 0.1 R² = 0.0029 Swainson's Thrush 0.05 y = 0.0003x + 0.0351 R² = 0.0079 0 150 160 170 180 190 200 210 Julian Day
Methylmercury Bioaccumulation within Sphagnum Bog and Northern Hardwood Forest Foodwebs How does mercury bioaccumulate from the base of the terrestrial food chain to • top predator, songbird species? Do mercury concentrations in biota vary between Sphagnum bog and adjacent, • northern hardwood forests due to differences in mercury cycling? Are there detectable seasonal and species-specific patterns within and between • study sites?
Methylmercury Bioaccumulation within Sphagnum Bog and Northern Hardwood Forest Foodwebs Study Sites – 2008, 2009, 2011 Spring Pond Bog Massawepie Mire Bloomingdale Bog Madawaska Flow Spatial Sampling Sphagnum Bog vs Hardwood Forest Temporal Pattern Early Season - Late May Mid Season – Late June Late season – Late July Species Comparisons Bog Birds : Palm Warbler, Lincoln’s Sparrow, Nashville Warbler Forest Birds : Ovenbird, Hermit Thrush, and Red-eyed Vireo
Breeding Songbirds : 2008-2009. Palm warblers and Red-eyed vireos had the highest Hg concentrations compared to other species. These species may be at higher risk to the impacts of Hg contamination than other associated bog and forest species. Blood Mercury Values (ppm) for Songbird Species at Bloomingdale Bog, Madawaska Flow, Massawepie Mire and Spring Pond Bog: 2008-2009 2 Mean Blood Mercury (ppm) Maximum Species Level Detected 1.8 1.6 LOAELs associated with 10% (0.69 ppm), 20% (1.23 ppm), 30% (1.70 ppm) reduced nesting success were determined by Jackson et al. (2010). 1.4 Mean Blood Mercury (ppm, ww) 1.2 1 0.8 0.6 0.4 0.2 0
Mercury Exposure by Habitat Type : 2008-2010. At all sites, Bog species were elevated over adjacent, forest species. Hardwood forests adjacent to bog habitats have forest songbirds with higher mercury levels than those documented in the Whiteface study. Blood Mercury Values (ppm) for Sphagnum Bog and Forest Songbird Species at Bloomingdale Bog, Madawaska Flow, Massawepie Mire, Spring Pond Bog (2008-2009) and Whiteface Mountain (2009-2010). 1 0.9 0.8 Mean Blood Mercury (ppm, ww) 0.7 0.6 Forest 0.5 Bog 0.4 0.3 0.2 0.1 0 Bloomingdale Bog Madawaska Flow Massawepie Mire Spring Pond Bog (n= Whiteface Mountain (n=22, 17) (n=20, 24) (n=22, 12) 16, 20) (n=88) Site
Seasonal Patterns - Mercury Exposure in Sphagnum Bog Species : Lincoln’s Sparrow show a decrease in Hg concentrations during the field season, while Nashville and Palm Warbler show slight increases. Blood Mercury Values (ppm) for Sphagnum Bog Songbird Species at Bloomingdale Bog, Massawepie Mire, Madawaska Flow and Spring Pond Bog: 2008 - 2009 2 1.8 1.6 Lincoln's Sparrow Mean Blood Mercury (ppm) 1.4 y = -0.0042x + 1.0075 R² = 0.2062 1.2 1 Nashville Warbler y = 0.0012x - 0.1263 R² = 0.0936 0.8 0.6 Yellow Palm 0.4 Warbler y = 0.0061x - 0.4651 R² = 0.1115 0.2 0 140 150 160 170 180 190 200 210 220 Julian Day
Seasonal Patterns - Mercury Exposure in Forest Species : All species show decreases in mercury concentrations during the field season, which may be linked to seasonal dietary shifts and mercury concentrations in selected prey species. Blood Mercury Values (ppm) for Forest Songbird Species at Bloomingdale Bog, Massawepie Mire, Madawaska Flow and Spring Pond Bog: 2008 - 2009 1.4 1.2 Hermit Thrush Blood Total Hg (ppm) 1 y = -0.0018x + 0.4688 R² = 0.2024 0.8 Ovenbird 0.6 y = -0.0008x + 0.2269 R² = 0.5711 0.4 Red-eyed Vireo y = -0.0041x + 1.0855 0.2 R² = 0.143 0 140 150 160 170 180 190 200 210 220 Julian Day
CONCLUSIONS • Montane ~ High elevation songbirds had elevated Hg levels as compared to low-elevation songbirds • Habitat Type ~ Bog-obligate songbirds had higher Hg levels than nearby forested species. Reinforced by BRI efforts relating high Hg levels to bog habitats • Species Patterns ~All bog and forest sites identified certain species with higher Hg exposure – Yellow Palm Warbler and Red-eyed Vireo • Sphagnum Bog Influence ~ Elevated Hg levels in forest songbirds suggest that Sphagnum bog systems are driving high Hg levels in biota within the immediate and surrounding environment • Further research needed to better characterize the dynamics of mercury cycling through sensitive, terrestrial foodwebs
Acknowledgements Research Committee: • Charles Driscoll • David Evers • Mark Ritchie • Al Uy Funding & In-Kind Support: • New York State Energy Research and Development Authority • BioDiversity Research Institute • Northeastern Ecosystem Research Cooperative
Acknowledgements Biology Lab Members: Environmental Engineering Lab Members: Megan McSherry Mario Montesdeoca Andrew Siefert Ed Mason Geofrey Soka Brad Blackwell Jason Townsend Field Assistance: Melissa Duron Julia Braunmueller Chelsea Baldino Grace Conklin Sara Nason Kendra Nash
Recommend
More recommend
