Detecting and Understanding Threats to Eelgrass in the Gulf of Maine: The Times, They Are A- Changin

Transcription

1 College of William and Mary W&M ScholarWorks Presentations Detecting and Understanding Threats to Eelgrass in the Gulf of Maine: The Times, They Are A- Changin Hillary A. Neckles Follow this and additional works at: Part of the Marine Biology Commons, and the Terrestrial and Aquatic Ecology Commons Recommended Citation Neckles, Hillary A.. "Detecting and Understanding Threats to Eelgrass in the Gulf of Maine: The Times, They Are A-Changin " VIMS 75th Anniversary Alumni Research Symposium. This Presentation is brought to you for free and open access by W&M ScholarWorks. It has been accepted for inclusion in Presentations by an authorized administrator of W&M ScholarWorks. For more information, please contact

2 Detecting and Understanding Threats to Eelgrass in the Gulf of Maine: The Times, They Are A-Changin Hilary Neckles 90 USGS Augusta, ME

3 Natural Disturbance Threats to Eelgrass Indirect Human Impacts: Upland development Direct Human Disturbance Global Climate Change Hydrologic/ Physical Alterations Chemical Inputs Altered Sediment Processes Altered Landscape Species Introduction Biological Structure Physical Environment Ecosystem Function

4 Natural Disturbance Threats to Eelgrass Indirect Human Impacts: Upland development Direct Human Disburbance Global Climate Change Hydrologic/ Physical Alterations Chemical Inputs Altered Sediment Processes Altered Landscape Species Introduction Biological Structure Physical Environment Ecosystem Function

5 Watershed Impacts on Coastal Water Quality Human Population Density Nitrogen Load Persons per square mile Modeled N load, kg yr -1 NOAA National Ocean Service/US Census, 2003 USGS SPARROW Model, 2002

6 Relative Effects of Nutrient Enrichment and Grazing VIMS SAV Greenhouse 1987 Neckles et al Oecologia 93:

7 Relative Effects of Nutrient Enrichment and Grazing VIMS SAV Greenhouse 1987 Neckles et al Oecologia 93:

8 Onward to the Gulf of Maine

9 Roworth, E. & R.P. Signell USGS Open File Report Bay of Fundy Gulf of Maine Browns Bank Scotian Shelf Georges Bank

10 Green, E.P. & F.T. Short World Atlas of Seagrasses. UNEP-WCMC. Eelgrass Distribution Gulf of Maine

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13 Seagrass Conservation Assess resource status Implement management options Diagnose causal relationships

14 Natural Disturbance Threats to Eelgrass Indirect Human Impacts: Upland development Direct Human Disturbance Global Climate Change Hydrologic/ Physical Alterations Chemical Inputs Altered Sediment Processes Altered Landscape Species Introduction Biological Structure Physical Environment Ecosystem Function

15 Trawling and Dragging Paul Cunningham

16 Hilary Neckles

17 Paul Cunningham

18 John Sowles

19 Mussel Dragging Causes Severe and Long-lasting Impact Percent Cover Shoot Density Dist/Ref Independent Recovery Trajectories: 9-11 years to reach 95% cover Casco Bay Space for time substitution Maquoit Bay Spatial simulation model Years Since Dragging Neckles et al Marine Ecology Progress Series 285:57-73.

20 Seagrass Conservation Assess resource status Implement management options Diagnose causal relationships

21 Seagrass Conservation Assess resource status Implement management options Diagnose causal relationships

22 Monitoring Challenges: Detecting trends before losses are irreversible Forecasting changes in distribution and condition Predicting changes on large spatial scale Efficient and affordable

23 Decreasing numbers of sites Decreasing spatial representation Increasing sample frequency Increasing number of variables Hierarchical Monitoring Framework Intensive monitoring Regional surveys Broad inventories and remote sensing Neckles et al Estuaries and Coasts 35:23 46.

24 Cape Cod National Seashore Tier 1 Mapping Tier 2 Baywide Survey Tier 3 Intensive Measures m Bed location Bed size Percent cover Canopy height Multiple linear regression model: Biomass is dependent on Percent cover, canopy height R 2 = 0.84 Percent cover Canopy height Shoot density Biomass Light, temp, seds

25 Natural Disturbance Threats to Eelgrass Indirect Human Impacts: Upland development Direct Human Disturbance Global Climate Change Hydrologic/ Physical Alterations Chemical Inputs Altered Sediment Processes Altered Landscape Species Introduction Biological Structure Physical Environment Ecosystem Function

26 Casco Bay Maquoit Bay Change in eelgrass in upper Casco Bay: the next two slides are views of the bed at the top of Maquoit Bay

27 2001 Hilary Neckles

28 2013 Hilary Neckles

29 Eelgrass Destroyed by Invasive European Green Crabs 56% loss of eelgrass area: 3,338 ha to 1,477 ha Neckles Northeastern Naturalist 22:

30 Hilary Neckles Impacts of eelgrass loss on shellfish calcification?

31 Expanding Populations of Invasive Colonial Tunicates Carman et al., Management of Biological Invasions, submitted

32 The Times, They Are A-Changin... It s even more complicated! Existing threats exacerbated by direct and indirect effects of global change Long-term sustainability of eelgrass in the Gulf of Maine will demand multi-faceted approaches

33 Thank you and best wishes for the next 75 years!