Management or demise of forests can affect water quality and quantity. Restoration of bottomland hardwoods, riparian forests on agricultural lands, and wetlands can help re-establish ecological functions and connections. Forest Watershed Science is working to provide knowledge and technology to generate social, economic, and environmental benefits.
The siricid woodwasp (Sirex noctilio) is an invasive nonnative pest of North American pines. The USDA Animal Plant Health Inspection Service will use the molecular tool Station scientists and partners developed to detect larvae in wood and dunnage intercepted at ports. The Forest Service and State forestry agencies will use the tool to detect larvae in living trees to identify priority control areas and monitor movement and dispersal. SRS is testing a nematode parasite used in Australian monocultural pine plantations as a biological control agent for Sirex noctilio. Scientists study effects on native insects and fungi to identify potential adverse effects to avert unexpected problems. Effective use of the nematode could prevent considerable economic losses.
Landscape-scale water quality benefits of establishing vegetated buffers, like riparian forest buffers, around cropland will result in greater benefits if applied on sites having greater buffering capability. National Agroforestry Center scientists produced a tool that utilizes USDA Natural Resource Conservation Service county-level soil surveys to support a targeted approach to placement and design of water quality buffers for controlling sediment and dissolved pollutants in surface runoff and groundwater. These methods provide estimates of how effective a standard buffer design would be in specific locations. The methods were designed for application across the Eastern U.S., but can be used anywhere for generalized assessments.
Hemlock woolly adelgid (HWA) is a nonnative invasive pest that impacts eastern and Carolina hemlocks. Without control, hemlocks typically die about 5 years after infestation. Neither natural predators nor host resistance have stopped the spread. Hemlocks are a keystone species in Southern Appalachian riparian areas, providing critical habitat for birds and other animals, and shading streams to maintain cool water temperatures required by trout and other aquatic organisms. Scientists are investigating impacts of hemlock mortality on streamflow, soil moisture, and nutrient and carbon cycling processes. The significance of the loss of hemlocks is magnified because it is likely no other species will fill its ecohydrological role.
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Impacts of Eastern Hemlock Mortality on Southern Appalachian Ecosystem |
Developing Biological Control for Sirex noctilio Woodwasp (Pine Borer) The siricid woodwasp (Sirex noctilio), introduced into forests in New York State and southeastern Ontario, is a major invasive nonnative insect pest of North American pines planted in the Southern Hemisphere. ...more... |
Southern Appalachian Trout Distribution in a Warmer Climate |
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More Water Quality per Buffer Buck: Using Soil Surveys to Guide the Placement of Water Quality Buffers |
Context-Specific Effects of Severe Drought on Freshwater Mussel Communities |
Restoration of Degraded Shortleaf Pine Ecosystems |
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GIS Model of Non-Breeding Range of Cerulean Warbler |
New watershed science products in 2007 ...more... |
Impacts of Eastern Hemlock Mortality on Southern Appalachian Ecosystems
Hemlock woolly adelgid (HWA) is a non-native invasive pest that impacts eastern and Carolina hemlocks. First reported in the 1950s in the Northeast, HWA has spread to the Southern Appalachian region of northern Georgia, western North Carolina, and southern Virginia. Without control, hemlocks typically die within about five years after infestation. Neither natural predators nor host resistance have stopped the spread. Hemlocks serve important ecological roles in the Southern Appalachians. They are a keystone species in riparian areas, providing critical habitat for birds and other animals, and shading streams to maintain cool water temperatures required by trout and other aquatic organisms. We quantified the impacts of hemlock mortality on hydrological process and predict that annual transpiration will be reduced by 10 percent, and winter and spring transpiration by 30 percent. We expect increases in streamflow and soil moisture may subsequently impact nutrient and carbon cycling processes. It is likely that no other species will fill the ecohydrological role of eastern hemlock if widespread mortality occurs. Chelcy Ford (cford@fs.fed.us)
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Developing Biological Control for Sirex noctilio Woodwasp (Pine Borer)
The siricid woodwasp (Sirex noctilio), introduced into forests in New York State and southeastern Ontario, is a major invasive nonnative insect pest of North American pines planted in the Southern Hemisphere. Damage to North American coniferous forests is expected to be extensive, especially in the South, if an effective control is not developed. The molecular tool we developed will be used by APHIS to detect larvae in wood and dunnage intercepted at ports of entry, and by the Forest Service and State forestry agencies to detect larvae in living trees. Larval detection in forests will help managers identify priority control areas, and help in monitoring movement and dispersal geographically, useful for hazard assessments and epidemiological studies. A.Dan Wilson (Dwilson02@fs.fed.us) and Nathan M. Schiff (nschiff@fs.fed.us)
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Southern Appalachian Trout Distribution in a Warmer Climate
In the Southern Appalachians, native brook trout and introduced rainbow and brown trout are highly prized for their existence and for recreational fishing. Distribution of wild trout is limited by temperature and is expected to be limited further by a warmer climate. Southern Station scientists produced a regional map of current wild trout habitat and developed models to project future distributions over a range of increased temperature. If predictions of the Hadley Global Circulation Model (GCM) are assumed, temperature in this region would increase by 2.3o C and approximately 53 percent of trout habitat would be lost. If the more extreme Canadian GCM prediction of a 5.5o C temperature increase is used, 97 percent would be lost. Fragmentation would increase, leaving populations in small isolated patches vulnerable to extirpation because recolonization is unlikely. Patricia A. Flebbe (pflebbe@fs.fed.us)
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More Water Quality per Buffer Buck: Using Soil Surveys to Guide the Placement of Water Quality Buffers
The landscape-scale water quality benefits of establishing vegetated buffers, like riparian forest buffers, around cropland will accrue to a greater extent if they are applied on sites having greater buffering capability than if they are applied evenly across the landscape. This scientific information must be translated into easy-to-use tools that can accurately identify those critical locations. National Agroforestry Center (NAC) scientists have produced a tool that utilizes readily available USDA-Natural Resource Conservation Service county-level soil surveys to support a targeted approach to the placement and design of water quality buffers. Simple methods were developed from process-based mathematical models for rating soil map units, using information provided in county soil surveys, to identify relatively better locations for placing buffers for controlling sediment and dissolved pollutants in surface runoff and dissolved pollutants in groundwater. These methods also provide estimates of how effective a standard buffer design would be in each location for controlling pollutants in surface runoff. Mike Dosskey (mdosskey@fs.fed.us)
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Context-Specific Effects of Severe Drought on Freshwater Mussel Communities
Freshwater mussel populations are often small and fragmented due to stream and landscape degradation. Isolated populations are highly vulnerable to natural disturbance. We studied five small stream sites on Bankhead National Forest heavily impacted by severe drought in 2000; one site dried almost completely and four sites experienced total or near cessation of flow. Three large stream sites retained flow and experienced minor streambed exposure. In small streams, mussel density before and after the drought declined by 65-83 percent. Most mussel species declined by similar percentages. Likelihood of survival was mostly a function of pre-drought abundance. Assemblage composition changed primarily due to loss of rare species, resulting in a shrinking species pool. We found no evidence for changes in total abundance or composition in large streams that continued to flow. Mussels are also highly sensitive to secondary effects of drought, most likely low levels of dissolved oxygen caused by low flow, warm temperatures, and high biological oxygen demand. Wendell R. Haag (whaag@fs.fed.us) and Melvin L. Warren (mwarren01@fs.fed.us)
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Restoration of Degraded Shortleaf Pine Ecosystems
Interactions among past land use, fire exclusion, drought, and southern pine beetle have caused substantial pine mortality and degradation of pine/hardwood stands in the southern Appalachians. Land managers are now challenged with the task of (1) reducing wildfire risk from widespread dead, fallen, and dying trees, (2) restoring beetle-killed forests, and (3) reducing the potential for development of stand conditions that promote increased fire risk. Land managers need information on management options that will accomplish these three goals in cost effective and practical ways. We studied the effectiveness of prescribed fire as a restoration tool in degraded shortleaf pine/bluestem ecosystems and determined that while understory burning does not adversely impact water quality, long-term site productivity, or forest floor dwelling macroinvertebrates, fire alone is not sufficient to create conditions required to regenerate shortleaf pine or increase bluestem abundance. Our current research is examining the effectiveness of more aggressive treatments, such as felling dead pines prior to burning, followed by planting shortleaf pine seedlings and seeding warm season grasses. Katherine Elliott (kelliot@fs.fed.us)
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GIS Model of Non-Breeding Range of Cerulean Warbler
The footprint of mountaintop removal coal mining in its breeding range and of coffee production in its nonbreeding range mark cerulean warbler as a species for whom integration of land management, conservation, and productive economic activity will be essential to future existence. By bringing together a large group of experts in geographic information systems and bird biology to analyze existing distribution records and relate them in a rigorous way to data on land forms, climate, and vegetation in the northern Andes, the members of El Grupo Cerúleo, subcommittee of the Cerulean Warbler Technical Group, produced a hypothetical distribution of this important and representative species in South America. We pooled results of five different modeling approaches into a combined, consensus hypothesis of distribution. The strength of the hypothesis is that it can be tested with detailed fieldwork and improved through evaluation. Paul B. Hamel (phamel@fs.fed.us)
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