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Mark Anderson

The Nature Conservancy (TNC) recently completed an unprecedented assessment of almost 14,000 dams in the Northeastern United States. The Northeast Aquatic Connectivity (NAC) project allows fisheries managers and other interested parties to assess dams at multiple scales based on their potential to benefit anadromous and resident fish species if removed or bypassed. This work has continued, with support from NOAA and USFWS, in the Chesapeake Bay watershed, where data refinements and further analysis have produced a web map and tool that allow users to interactively prioritize dams for mitigation at multiple scales and with varying criteria.The Southeast Aquatic Resources Partnership (SARP) has recently completed...
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This shapefile represents The Nature Conservancy’s (TNC) “essential forests” and “key connectors” in the Central Appalachians Whole System. Essential Forests are built around groups of large forest patches, ecoregional portfolio roll-up sites, and areas with high local integrity and high flow density (from M. Anderson’s resiliency analysis). Key Connectors provide physical linkages among essential forests, have high flow density, and may also include large forest patches and matrix blocks. The polygons were originally delineated by TNC staff at a workshop near Petersburg, West Virginia, on March 9 and 10, 2011. The boundaries were hand-drawn on paper maps and then hand-digitized by A. Watland (TNC-VA) and T. Gagnolet...
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Between 1999 and 2005, drought in the western United States led to a >44 m fall in the level of Lake Powell (Arizona-Utah), the nation's second-largest reservoir. River discharges to the reservoir were halved, yet the rivers still incised the tops of deltas left exposed along the rim of the reservoir by the lake-level fall. Erosion of the deltas enriched the rivers in sediment such that upon entering the reservoir they discharged plunging subaqueous gravity flows, one of which was imaged acoustically. Repeat bathymetric surveys of the reservoir show that the gravity flows overtopped rockfalls and formed small subaqueous fans, locally raising sediment accumulation rates 10–100-fold. The timing of deep-basin deposition...
Categories: Publication; Types: Citation; Tags: Geology
Developing consistent region-wide information to ensure enough water for people and wildlife.
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In response to the need and an intergovernmental commission for a high resolution and data-derived global ecosystem map, land surface elements of global ecological pattern were characterized in an ecophysiographic stratification of the planet. The stratification produced 3,923 terrestrial ecological land units (ELUs) at a base resolution of 250 meters. The ELUs were derived from data on land surface features in a three step approach. The first step involved acquiring or developing four global raster datalayers representing the primary components of ecosystem structure: bioclimate, landform, lithology, and land cover. These datasets generally represent the most accurate, current, globally comprehensive, and finest...
Categories: Publication; Types: Citation
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