nena masthead
SENA Home Staff & Editors For Readers For Authors

Terrestrial and Longitudinal Linkages of Headwater Streams
J. Bruce Wallace and Sue L. Eggert

Southeastern Naturalist, Volume 14, Special Issue 7 (2015): 65–86

Full-text pdf (Accessible only to subscribers.To subscribe click here.)

 



Access Journal Content

Open access browsing of table of contents and abstract pages. Full text pdfs available for download for subscribers.

Issue-in-Progress: Vol. 23 (1) ... early view

Current Issue: Vol. 22 (3)
SENA 22(3)

Check out SENA's latest Special Issue:

Special Issue 12
SENA 22(special issue 12)

All Regular Issues

Monographs

Special Issues

 

submit

 

subscribe

 

JSTOR logoClarivate logoWeb of science logoBioOne logo EbscoHOST logoProQuest logo


Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 65 Canaan Valley & Environs 2015 Southeastern Naturalist 14(Special Issue 7):65–86 Terrestrial and Longitudinal Linkages of Headwater Streams J. Bruce Wallace1,2,* and Sue L. Eggert1,3 Abstract - Headwater streams are important habitats for aquatic organisms. Within forested regions, headwater streams and riparian corridors function as zones of deposition, storage, processing, and subsequent transport of organic matter. In forested streams, organic matter from the adjacent forest provides the major fuel for the aquatic ecosystem. Along with habitat, headwater streams perform many valuable ecosystem services such as nutrient, hydraulic, and sediment retention; provide thermal refuges; and function as important sites of secondary production for higher animals. Headwater streams are being subjected to many anthropogenic impacts including dams, urbanization, agriculture, forestry, and mining. Ecologists should promote the importance of headwater streams, as well as devote more research to examining entire stream networks, rather than just studying individual longitudinal linkages. Introduction Extensive forest cover, rugged relief, abundant rainfall, and thousands of small streams characterize the Central and Southern Appalachian Mountains. These small streams are the headwaters, or portions of headwaters, of many large rivers including the Alabama, Chattahoochee-Apalachicola, Delaware, James, Ohio, Potomac, Roanoke, Santee, Savannah, Susquehanna, Tennessee, and Yadkin-Pee Dee. These rivers represent a critical water resource for many major downstream cities (Wallace et al. 1992). The proper management of headwaters is vital to maintaining down-river water quality. In many respects, Canaan Valley, a high-elevation wetland with many tributary streams, is an excellent example of the effects of past misuses of our headwaters. Since the area’s early colonization, these streams have suffered serious impairments, including those from extensive logging, (especially from 1900 to the 1920s), mining and acid mine drainage, agriculture, urbanization, and road construction (Meyer and Wallace 2001). Our objectives here are to emphasize the linkages between headwater streams and their terrestrial ecosystems, as well as linkages between headwaters and downstream reaches. Such linkages are critical for understanding lotic systems and how impairment in one reach may impact downstream segments. Here we review the literature regarding how these links have contributed to our overall understanding of several aspects of ecosystems, including 1) detrital food webs, 2) biogeochemistry and nutrient dynamics, 3) linkages between 1Department of Entomology, University of Georgia, Athens, GA 30602. 2Odum School of Ecology, University of Georgia, Athens, GA 30602. 3Current address - USDA Forest Service, Northern Research Station, 1831 Highway 169, Grand Rapids, MN 55744. *Corresponding author - bwallace@uga.edu. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 66 ecosystems, and 4) ecological consequences of exotic species, as well as the role of the linkages as indicators of ecosystem change. Headwater, Downstream, and Terrestrial Linkages Role of invertebrates in detrital processing Most headwater streams in the Appalachians drain forested or previously forested watersheds. Even in winter, many of these streams have extensive canopy cover by a dense riparian understory of evergreen Rhododendron spp. In-stream primary production tends to be a small fraction of total organic matter available for heterotrophic organisms such as bacteria, fungi, and invertebrates (Webster and Meyer 1997, Webster et al. 1995). Most of the energy base of these streams comes from the surrounding forest in the form of coarse particulate organic matter (CPOM), which consists of leaves, woody debris, and significant amounts of dissolved organic carbon (DOC) carried by groundwater (Webster and Meyer 1997). The invertebrates in these streams rely primarily on detritus and its associated microbial assemblage for most of their secondary production (Hall et al. 2000, Rosi-Marshall and Wallace 2002). In the process of gleaning their nutrition from this detritus, invertebrates also play an important role in detrital processing and upstream-to-downstream linkages. It has long been known that many invertebrates, primarily insects, readily consume autumn-shed leaves that fall into streams (e.g., Hynes 1941, Petersen and Cummins 1974, Wallace et al. 1999). How important are these invertebrates in processing organic matter at the ecosystem level? On 2 different occasions, 2 headwater streams at the Coweeta Hydrologic Laboratory in western North Carolina were treated with the insecticide methoxychlor. These treatments caused 4 effects. First, massive invertebrate drift, primarily of immature insects, resulted in altered community structure (Lugthart and Wallace 1992, Wallace et al. 1989, 1991b). Second, the abundance, biomass, and secondary production of invertebrates were reduced, especially of aquatic insect taxa (Lugthart and Wallace 1992, Lugthart et al. 1990). There was a corresponding increase in the abundance of non-insect taxa, primarily oligochaetes, copepods, and turbellarians. Third, there were lower rates of leaf-litter processing without reductions in microbial respiration or fungal diversity (Cuffney et al. 1990, Suberkropp and Wallace 1992). Fourth, by the end of the 3rd summer of treatment, the leaf litter standing crop increased 2.5- to 3-fold in the treatment stream compared with the 2 reference streams (Wallace et al. 1991a). Leaf-litter processing rates remained low throughout the pesticide treatment, but subsequently increased during recovery (Chung et al. 1993) due to fairly swift recolonization by aerial adults of several taxa (Wallace et al. 1991b, Whiles and Wallace 1992). Assimilation efficiency of most leaf-shredding insects is low: ≈10% (Wallace and Hutchens 2000), with ≈90% of the ingested material egested as fine organic particles. These small particles are much more easily transported downstream than is CPOM. Compared to reference streams, reductions in the processing rates Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 67 of organic matter in the treatment stream were followed by a 5-fold reduction in the export of fine particulate organic matter (FPOM; Cuffney et al. 1990). During the experiment, the export of FPOM from this small headwater stream was reduced by ≈170–200 kg ash-free dry mass (AFDM) (Wallace et al. 1991a). Invertebrate manipulation changed the stream’s seasonal export response to storms (Wallace et al. 1991a) and reduced export during storms (Cuffney and Wallace 1989). As the invertebrates recovered in the treatment stream, FPOM concentrations and export increased. Effects of the insecticide treatments on the stream’s FPOM export were as great as those produced by a range of discharges encompassing a 57-y record (Wallace et al. 1991a). Applying the measure of FPOM export per 100 m of wetted first-order channel during the pesticide manipulation to the 33.3 km of first-order channels in the 1600-ha Coweeta Basin, we conclude that the macroinvertebrate activities of the headwaters contribute ≈6 to 7 tons of FPOM to the basin’s downstream reaches annually. This study demonstrated the importance of stream biota, particularly invertebrates, on the processing of CPOM and subsequent export of FPOM. Collectively, these studies emphasize the importance of maintaining biodiversity in the headwaters as an important consideration in downstream management (Lugthart and Wallace 1992, Wallace et al. 1991a). Importance of longitudinal linkages In addition to local physical gradients, several kinds of large-scale physical changes occur along stream gradients. These longitudinal changes are incorporated into a general framework of riverine ecosystems known as the river continuum concept (RCC) (Minshall et al. 1983, Vannote et al. 1980). Since the RCC was proposed, the results from a number of studies around the world have indicated that changes in energy supply and biological communities as proposed in the RCC are not applicable to all river systems (e.g., Cushing et al. 1995, Meyer 1990, Statzner and Higler 1985). Many biological attributes of streams in the Little Tennessee River Basin of the Southern Appalachian Mountains are similar to those proposed in the original RCC, although some exceptions exist (Grubaugh et al. 1997). Striking differences in the production of invertebrate assemblages occurred between the headwaters and downstream reaches of the Little Tennessee (Grubaugh et al. 1997). Shredders, gatherers, and predators dominated the invertebrate assemblage production in the headwaters, whereas in the larger downstream reaches of the Little Tennessee River, 80% of the secondary production was attributed to filter-feeding taxa, which are adapted to remove particles from suspension. At the large river sites, production per m2 of substrate was 20 times greater than that of the shaded headwater stream (Grubaugh et al. 1997). The dissimilarities in production and community structure between up- and down-stream sites of the Little Tennessee River resulted from unequal distribution of resources along the river gradient (Wallace and Hutchens 2000). Hall et al. (2000) and Rosi-Marshall and Wallace (2002) used the trophic basis of production method (Benke and Wallace 1980) to estimate the annual food consumption by Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 68 invertebrates at up- and down-stream sites. Invertebrates in the headwaters consumed primarily leaf and amorphous detritus stored in the stream, which is easily obstructed by woody debris and highly retentive of CPOM. In contrast, primarily amorphous detritus and animal tissue were consumed in downstream areas (Rosi- Marshall and Wallace 2002). In the headwater stream draining a deciduous forest, there was an abundant supply of stored benthic organic matter, which was 8 times greater than that found downstream. In contrast, annual transport of organic matter per linear meter of stream of the larger river site exceeded that of the headwater stream by >260 times. Thus, there were large differences in the form of the organic matter, namely stored vs. transported, that were available to the benthic animal assemblages, and these were reflected in the functional structure of these assemblages. Specifically, shredders and collectors were dominant in upstream reaches, whereas filter feeders predominated in downstream areas. Filter-feeding organisms in the Little Tennessee River were supported by the most available resource, FPOM in transport, which was delivered from upstream areas. In small headwater streams, where the physical environment stores organic particles, invertebrate assemblages are dominated by shredders, gatherers, and invertebrate predators (Wallace and Hutchens 2000). Their feeding actions tend to decrease the particle size of the organic resources and favor the downstream export of FPOM, which is more easily transported than the larger CPOM. In contrast, downstream reaches experience higher discharge, greater stream power, and less retention, all of which promote the entrainment of organic matter. Again, the invertebrate assemblage exploits the physical characteristics of the system, supporting a dominance of filter feeders (Grubaugh et al. 1997), which promote the retention of entrained organic matter. Thus, in both up- and downstream reaches, the invertebrate feeding assemblages have evolved to effectively use the physical characteristics offered by the system. The result is a linkage between the upstream assemblages that break down and transport organic matter and the downstream assemblages that feed on the transported material. Invertebrates are exported from headwater streams via downstream drift and become important food sources for downstream animals such as fish. Invertebrate export from fishless headwater streams in southern Alaska was estimated to support 100 to 2000 young-of-the-year salmonids to downstream habitats (Wipfli and Gregovich 2002). Terrestrial-aquatic linkages Forested headwater streams are intimately connected with their adjacent terrestrial environment (Gomi et al. 2002, Hutchens and Wallace 2002, Richardson 2000). Terrestrially derived inputs of organic matter, leaves, and woody debris are the fuels that drive productivity within small streams (Fisher and Likens 1973, Richardson 1991, Webster and Meyer 1997). An ecosystem-level manipulation of organic matter inputs over an 8-y period in the Southern Appalachian Mountains of western North Carolina provided compelling evidence of the tight coupling between headwater streams and their riparian habitats. A gill-net Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 69 canopy constructed over a 170-m stream reach, starting at a headwater spring seep, excluded allochthonous inputs from the surrounding forest (Wallace et al. 1997, 1999). A nearby reference stream served to distinguish the effects of litter exclusion from natural variation. Most leaf litter disappeared from the exclusion stream within 6 months. The loss of leaf litter in the stream bottom resulted in a pulse of organic and inorganic particles as they were flushed from the stream (Eggert et al. 2012). Then, after 3 years of litter exclusion, all small wood was manually removed. Two years later, all large woody debris was removed by hand from the stream channel. The benthic storage of organic material declined further as the wood was removed from the stream bottom. Removals of benthic organic matter during the first 4 years of exclusion resulted in a 78% decline in invertebrate secondary production in the mixed substrates of the exclusion stream compared to pretreatment years (Wallace 1999). By the end of the study, secondary production in the exclusion stream was the second lowest ever measured for a north temperate stream when compared to other streams (Benke 1993). The shredder and gatherer functional feeding groups, which depend on organic matter from the terrestrial environment, were impacted most severely. Some detritivores with flexible feeding habits, such as species of Tipula spp. (crane flies) and Tallaperla (stoneflies), switched diets from leaf material to wood prior to wood removal, and then switched to amorphous detritus after wood removal (S.L. Eggert et al. unpubl. data, Hall et al. 2000). Other taxa, such as the caddisfly Pycnopsyche gentilis (McLachlan), did not shift their diets and, consequently, were extirpated from the litter-depleted stream (Eggert and Wallace 2003). The negative effects of these reduced detrital inputs were observed up the food chain to invertebrate predators and salamanders, the top predators in these small streams. Populations of Eurycea wilderae Dunn (Blue Ridge Two-lined Salamander) were significantly smaller and individuals grew at slower rates compared to the reference stream (Johnson and Wallace 2005). The flow of organic materials between terrestrial and aquatic habitats is not just unidirectional. Rather, organic matter and immature aquatic insects from the stream bottom can be deposited within the riparian zone during large storms (Hutchens and Wallace 2002, Wallace et al. 1995). Emerging aquatic insects travel up into the riparian zone, where they serve as food for terrestrial organisms (Nakano and Murakami 2001, Sabo and Power 2002, Sanzone 2001). Biogeochemistry and nutrient dynamics Anthropogenic inputs of nutrients from the burning of fossil fuels, wastewater discharges, fertilizer applications, and urban runoff have altered nutrient cycles in streams of the Appalachians and around the globe (Carpenter et al. 1998). Headwater streams are important zones of nutrient uptake and thereby reduce downstream nutrient loading. In the late 1990s, a team of scientists from a number of institutions around the US started the Lotic Intersite Nitrogen eXperiment (LINX), in which they studied the transformation and uptake of nitrogen (N) in various-sized streams at 12 sites, most of which were long-term ecological research sites representing a diverse range of biomes. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 70 To trace the uptake and transformation of N, the LINX team released 15N into streams. Headwater streams retained >50% of the inorganic N inputs (Peterson et al. 2001). Nitrogen was transformed or removed quickly from small streams, often within minutes to hours of its input. The shortest uptake distances of N were in the smallest streams. There was much less uptake, as indicated by longer distances traveled by N, in larger streams with higher discharge. These findings suggest that small streams are more important than large ones in regulating N dynamics. Small streams are often filled with organic detritus from their riparian habitats and have small cross-sectional areas that allow maximum interface between substrates and the flowing water. In conjunction with the litter-exclusion study in the Southern Appalachians, Meyer et al. (1998) found that the biogeochemistry of dissolved organic carbon (DOC) was altered after the elimination of leaf litter inputs. DOC generated from leaf litter that had been deposited in small streams contributed about 30% of the daily DOC export. Since DOC is an important source of organic matter in stream food webs, its absence from streams that have been decoupled from their terrestrial habitats would negatively impact higher trophic levels (Meyer 1994). The average uptake distance of phosphorus and ammonium increased following leaf-litter exclusion, and increased even more after woody debris was removed (Webster et al. 2000). In these small streams, microbial organisms colonize the surfaces of leaves and small woody debris, and immobilize dissolved nutrients (Tank and Webster 1998, Tank et al. 1998). Leaves and wood in small streams also serve to slow the flow of water. The presence of leaves, wood, and their associated microbes reduces the movement of nutrients to downstream reaches. In essence, small streams are like the vertebrate kidney—they clean the system of wastes (Meyer 1990). As with the flow of organic matter between a stream’s channel and its terrestrial environment, nutrients likewise can move from stream to land. A wellknown example of this phenomenon is the transfer of marine-derived nutrients by salmon in the Pacific Northwest (Gende et al. 2002, Naiman et al. 2002). Nutrients released from salmon carcasses after spawning stimulate the production of periphyton and invertebrates in headwater streams (Chaloner and Wipfli 2002, Wipfli et al. 1998). Bears, birds, and other mammals transport nutrients in the form of salmon carcasses from streams to the terrestrial environment when they consume carcasses directly (Hilderbrand et al. 1999), or feed on the increased invertebrate biomass (Gende and Willson 2001). Salmon-derived nutrients may also increase the growth of riparian vegetation (Helfield and Na iman 2001). Problems with assessing small streams As we have said, small streams are critical to the functions of their larger drainage network. Unfortunately, the value of small streams is often underappreciated and underestimated (Meyer and Wallace 2001), in part because the streams are inadequately mapped. First-order streams make up 48% of the total river miles in the United States (Leopold et al. 1964). However, maps of basin networks are usually drawn at a scale of 1:24,000 or larger, which excludes the Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 71 smallest streams (Leopold 1994). In the Coweeta Creek basin for example, >98% of the total stream length is unaccounted for on 1:500,000-scale maps (Table 1). Many of the smallest streams do not appear on 1:7200-scale maps. It is ironic that >190 papers have been published on research in Coweeta headwaters that do not exist according to USGS maps (Meyer and Wallace 2001). For the Chattooga River watershed in the Blue Ridge Mountains of Georgia, North Carolina, and South Carolina, only 50% and 75% of the perennial streams were shown on 1:100,000- and 1:24,000-scale maps, respectively (Hansen 2001). Almost none of the intermittent and ephemeral streams in the Chattooga basin were drawn on either map. The problem exists because there are no hydrologic criteria for mapping ephemeral (shown as dashed blue lines) and perennial (solid blue lines) streams on US Geological Survey maps. Most headwater streams are mapped according to the personal aesthetics of laboratory-bound technicians (Leopold 1994). Hansen (2001) defined perennial, intermittent, and ephemeral streams based on channel presence, flow duration, stream-bed water level (above channel, near channel surface, or below channel), aquatic insect presence, material movement, and channel materials. The state of West Virginia defines “intermittent stream” as a lotic system draining a watershed of >2.6 km2. West Virginia also uses a biological criterion in which streams are classified as intermittent if they do not support species that require a continuous aquatic period of >6 months. Many small drainages and spring seeps of <20 ha support animals with multiyear life cycles, but they appear as dashed blue lines on topographic maps. To protect all of the surface waters of the US under the federal Clean Water Act, biologically meaningful and hydrologic definitions of the smallest streams must be determined as soon as possible. Small streams under assault Headwater streams in the Appalachians tend to be stenothermal, that is, they have narrow ranges of temperatures, compared to downstream areas (e.g., Vannote and Sweeney 1980). They offer thermal refuges to many unique species of invertebrates and amphibians. Very few taxonomic studies to the species level have been published about the intermittent and permanent small streams of the Central Appalachians. However, even given the limited data, Meyer et al. (2007) and Morse et al. (1993, 1997) point out that much of Appalachia’s biodiversity Table 1. Stream distances in the Coweeta Hydrologic Laboratory (16.3 km2) in western North Carolina from maps of various scales.1 Map scale Kilometers of streams 1:500,000 0.8 km 1:24,000 24.4 km 1:7200 56.0 km* 1Data from Meyer and Wallace (2001). *There are many permanent streams that do appear on the 1:7200 scale maps. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 72 and unique fauna are found in these headwater streams. Unfortunately, as the latter authors point out, small headwater streams are under assault from a variety of anthropogenic disturbances. Ecological consequences of exotic species Exotic aquatic species alter the community dynamics of steams and compete with native species for preferred habitat. With the exception of Oncorhynchus mykiss (Rainbow Trout) replacing Salvelinus fontinalis (Brook Trout) in secondand third-order streams of the Southern Appalachians (Larson and Moore 1985), the headwaters of the Appalachian Mountains have not been tremendously affected by non-native species. Because Rainbow Trout compete with Brook Trout for food (Ensign et al.1990), Rainbows may affect the Brook Trout habitat selection and growth rates (Lohr and West 1992, Whitworth and Strange 1983). Exotic species also affect the linkage between headwater streams and the terrestrial environment adjacent to them. Some terrestrial exotics have caused large changes in headwater stream habitat. For example, outbreaks of terrestrial non-native invasive species, such as Adelges piceae (Ratzeburg) (Balsam Woolly Adelgid), A. tsugae (Annand) (Hemlock Woolly Adelgid), and Lymantria dispar dispar L. (Gypsy Moth), can cause riparian canopy loss, and pesticides used in eradication protocols enter nearby streams via runoff. Both infestation and treatment affect stream functions (Griffith et al. 1996, Hutchens and Benfield 2000, Orwig 2002, Snyder et al. 2002, Webster et al. 2012). Non-native scales and fungi cause diseases such as dogwood anthracnose and beech bark disease, which have already invaded forests of the Appalachian Mountain region. The fungus that causes butternut canker is beginning to spread rapidly in the region (Ward and Mistretta 2002); another introduced fungus that causes chestnut blight eliminated Castanea dentata (Marsh.) Borkh. (American Chestnut) from eastern forests. The blight and resulting eradication of American Chestnut has had lasting impacts on Appalachian streams including decreased leaf-litter processing, lower quality of litter inputs, and slower invertebrate growth rates in headwater streams (Smock and MacGregor 1988, Wallace et al. 2001). Blight-related Chestnut mortality caused input of large woody debris into streams between 1934 and the 1950s, before the second logging of the Appalachian forests. This fortuitous timing facilitated the retention of sediment and served to stabilize stream channels after subsequent logging (Wallace et al. 2001). Clearly, introduced species within streams and riparian habitats can have long-lasting effects on the functions of headwater streams. Agriculture Filling and tiling of wetlands and headwater streams for agriculture has greatly reduced the surface area of water in the Appalachians and worldwide. For example, the drainage density of the Kävlinge River catchment in Skåna, a southern province of Sweden, was severely altered for extensive agriculture (Wolf 1956). Between 1812 and 1953, 96.6% of the original surface water area in the catchment was lost to channelization and drainage for farming. Along Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 73 with the losses of small streams, intensive agriculture has caused nitrate levels in water to exceed safe drinking levels. Over-fertilization of agricultural land in low-order sections of river networks often affects downstream river reaches. David and Gentry (2000) estimated that agricultural sources in Illinois contributed 10–15% of the nitrogen and phosphorus loads to the Mississippi River. Dramatic shifts in the invertebrate community associated with increased sedimentation and temperature have been observed from headwater to downstream reaches of agriculturally impacted streams (Harding et al.1999). Stream fishes are also susceptible to sediment inputs from agricultural activities (Walser and Bart 1999, Waters 1995). Along with sedimentation effects, insecticide runoff from agricultural fields into headwater streams can have deleterious impacts on stream water quality (Liess et al. 1999). In the Appalachians, agricultural activity has the potential to modify and reduce the diversity of stream biota for many years after reforestation (Harding et al. 1998). In 1940, a mountain farm experiment began at Coweeta Hydrologic Lab using standard Southern Appalachian farming techniques (mule and plow). Initially, increases in neither storm runoff nor soil loss were observed, mainly due to the presence of organic matter in the soil (Hursh 1951). The disappearance of organic matter from the soil 3 years after clearing resulted in an average of 354 kg of sediment lost per day during May to September 1943. During one storm in 1949, 68,400 kg of sediment were carried into the stream in a 65-minute period. The effects of cattle grazing on the headwater streams of a mountain watershed were also demonstrated at Coweeta. No visible effects on stream water quality were observed over the first 8 summers of grazing (Hursh 1951). After the 9th summer of grazing, however, the 8 head of cattle had trampled an area large enough to cause increased storm runoff into stream channels, which flushed leaf packs from the small stream. Without leaf litter to trap sediment and slow the stormflow, the maximum effects were finally seen well after the experiment had begun, demonstrating the unique ecosystem services provided by the accumulations of organic matter in small streams (Hursh 1951). Urbanization and roads Urban-growth scenarios predict substantial (0.5 to >10%) increases in population and income growth for the Central and Southern Appalachians (Wear 2002). Losses of forested land are expected to occur in areas of increased urbanization. Deforestation extent is predicted to be greatest in the Southern Appalachian Piedmont, the Blue Ridge Mountains, the Ridge and Valley, and the Southern Cumberland Plateau (Wear 2002). The Canaan Valley has also experienced rapid growth in the last 30 years due to increases in recreation, tourism, and residential development (Waldron and Wiley 1996). The replacement of forested land and riparian habitats with impervious surfaces, such as roads and rooftops, alters stream hydrology and geomorphology (Elmore and Kaushal 2008, Finkenbine et al. 2000, Paul and Meyer 2001, Rose and Peters 2001). Increases in surface runoff associated with storm flow lead to Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 74 declines in water quality, including increased turbidity and bacterial populations (Bolstad and Swank 1997). Pesticide, herbicide, and fertilizer runoff into nearby streams during storms increased with urbanization as well (Hoffman et al. 2000, Winter and Duthie 2000). Increased sediment runoff and erosion from construction sites causes channel widening (Nelson and Booth 2002, Trimble 1997), resulting in habitat losses for aquatic life (Waters 1995). Fish species diversity and abundance declined significantly in Tuckahoe Creek, VA after 32 years of increased road construction, commercial and residential development, and riparian losses (Weaver and Garman 1994). In streams of southeastern Pennsylvania, only pollution-tolerant fish and macroinvertebrate species survive in urbanized streams (Kemp and Spotila 1997). Urbanization has also been associated with less-diverse, pollution-tolerant macroinvertebrate assemblages in streams of southeastern Wisconsin (Stepenuck et al. 2002), south-central Maine (Huryn et al. 2002), and Georgia Piedmont (Roy et al. 2003). Measurable aquatic degradation occurs as ~10% of a watershed’s area becomes impervious area (Booth and Jackson 1997; Wang et al. 2002, 2001). Construction of impervious surfaces, such as roads, has long been associated with decreased water quality of nearby streams (Duncan et al. 1987, Forman and Alexander 1998, Jones et al., 2000, Wemple et al. 2001). Ruth Cooper Allman, a lifelong resident of Canaan Valley, also wrote of the disappearance of “millions of Brook Trout in the streams when pioneers came to the valley” (Allman 1976). The construction of West Virginia Route 32 in 1932 resulted in so much sediment flowing into nearby streams that residents reported, “the water became so muddy in the spring that the fish either died or had to leave as they could not live in the muddy water” (Allman 1976). Skid trails and logging roads are often major sources of sediment in streams located in logged watersheds, and their presence has significant effects on aquatic organisms (Tebo 1955). Soil erosion from logging roads has been studied extensively at the Coweeta Hydrologic Laboratory (Swift 1988) and Fernow Experimental Forest (Trimble 1977). Guidelines for building environmentally friendly and low-cost forest roads have been pioneered through demonstration projects at both sites (Kochenderfer and Helvey 1987; Swift 1984a, b). Longterm monitoring at one of these demonstration projects (Watershed 7 at Coweeta) showed that copious sedimentation occurred only during storms immediately following road construction (Swank et al. 2001). Forestry practices Most Appalachian headwater streams were exposed to a major disturbance around the turn of the 19th–20th century with the widespread logging of the eastern deciduous forest. An excellent and informative account of the early logging in West Virginia, including the Canaan Valley and surrounding area, can be found in Clarkson (1964). Early logging obviously degraded streams as the logs were often floated downstream with the aid of splash dams, thereby scouring stream beds. Based on photographs (Clarkson 1964), it is evident that many log slides were constructed in the channels of small headwater streams. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 75 In addition to habitat alteration due to stream scour by floating logs, logging also causes other problems for streams and headwater biota. These effects include changes in stream temperature regimes (Swift 1983); greater discharge and altered hydrology (Bormann and Likens 1979, Swank et al 2001); increased levels of nutrients (Swank et al. 2001), solar radiation, and primary production (Duncan and Brusven 1985, Noel et al. 1986, Webster et al. 1983); more sediment export (Gurtz et al. 1980, Swank et al. 2001, Webster and Golladay 1984); and changes in the kinds and amounts of dissolved organic matter from the adjacent terrestrial ecosystem (Meyer and Tate 1983). These changes can be accompanied by large changes in the energy base of the stream, with a shift from allochthonous detritus to autochthonous production (Webster et al. 1983). The physical and energy-base changes can lead to large shifts in the structure of the macroinvertebrate community (Gurtz and Wallace 1984, Newbold et al. 1980, Noel et al. 1986, Stone and Wallace 1998). Invertebrate taxa with short life cycles and the ability to exploit increases in primary production greatly increase in population abundance, biomass, and productivity (Wallace and Gurtz 1986). Studies in the Central (Griffith and Perry 1991) and Southern Appalachians (Benfield et al. 2001) show that long-term patterns of leaf litter breakdown can be altered for many years after logging. However, depending upon the extent of terrestrial succession, invertebrate assemblages can revert toward their pre-logged and forested reference stream condition in about 15 y, although differences remain between reference and logged streams (Stone and Wallace 1998). Most of the studies cited above were performed in Southern Appalachian streams at the Coweeta Hydrologic Laboratory in western North Carolina. However, the data clearly show that logging causes an array of physical and biotic disturbances to streams draining logged catchments. The logging effects that probably cause the largest changes in benthic assemblages include increased solar radiation, altered thermal regimes, greater sediment with associated physical disturbance of the substrate, and increased water yield and sto rmflow. Dams and impoundments Dams and impoundments alter the ecology, geomorphology, temperature, and hydrology of river networks (Chin et al. 2002, Nislow et al. 2002, Stanford and Ward 2001). Alterations of flow regimes and stream network fragmentation that accompany impoundment lead to direct habitat loss, water quality degradation, and decreased biodiversity of aquatic species (Bunn and Arthington 2002, Dynesius and Nilsson 1994). Small impoundments are common in higher elevations in the Central and Southern Appalachians (Menzel and Cooper 1992, Merrill 2001). The number of these small impoundments, mostly in the form of ponds <10 ha in area, is staggering. In one northern Georgia Piedmont watershed, 46% of 6167 headwater streams have been impounded (Merrill 2001). Over 5400 of these small ponds had inundated 8% of the total stream length; the many dams severely fragmented the river network. Approximately 31% of the stream length had a downstream Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 76 impoundment within 5 km. Because 1:24,000 maps were used in this analysis, these values are most certainly underestimates due to streams and impoundments unmapped at this scale. Dam-building and feeding activities by Castor canadensis Kuhl. (Beaver) can also negatively affect the quantity and quality of headwater streams. In portions of the Canaan Valley, increasing Beaver populations have converted 17% of the total stream length to pond habitat and may contribute to lower dissolved oxygen levels in downstream reaches (Synder et al. 2006). Headwater streams flowing into impoundments have lower biological integrity than free-flowing streams (Merrill 2001). Fortunately, much of this impact can be reversed with dam removal, although responses vary between up- and down-stream areas, which proceed at different rates (Bednarek 2001, Hart et al. 2002). Longitudinal linkages are reestablished after dam removal, and mobile organisms, such as fish, can respond relatively quickly (Bushaw-Newton et al. 2002). Changes in channel geomorphology, and in sediment and nutrient transport, may take longer to respond to dam removal (Doyle et al. 2002, Hart et al. 2002, Pizzuto 2002, Stanley and Doyle 2002). Mining About 2017 km2 of the Central and Southern Appalachians were surface mined for coal between 1930 and 1971. Some 32% to 48% of this mined area was not reclaimed, and abandoned mines represent an on-going problem (Samuel et al. 1978). Invertebrate and fish populations were reduced for >20 years after mining operations ended. Odonata (Dragonflies and Damselflies), Ephemeroptera (Mayflies), Megaloptera (Alderflies, Dobsonflies and Fishflies), and Diptera (True Flies) were severely affected (Roback and Richardson 1969). Some of West Virginia’s rivers have been so severely degraded by coal mining, stream acidification, and industrialization, especially chemical plants, that only the more tolerant species of benthic organisms can inhabit them (Pond et al. 2008, Snyder et al. 2006, Tarter 1976). Selenium concentrations in mining effluent can reach levels 15 times the threshold for toxic bioaccumulation in aquatic organisms (Lemly 2008). These concentrations have caused teratogenic deformities and reproductive toxicity in fish of the Mud River ecosystem, WV (Lemly 2008). In recent years, heated controversy has developed around the practice of mountaintop removal and valley-fill coal mining (Palmer et al. 2010). As of 1998, some 1450 km of streams, primarily in West Virginia, Kentucky, Tennessee, and Virginia had been permanently buried by overburden from mining operations (USFWS 1998). Since these estimates of filled streams were made from a USGS 1:24,000-scale map, there is no doubt that the estimate of 1450 km is a significant underestimate. This continues to be one of the most important environmental concerns facing headwater streams in West Virginia. Conclusions Research has yielded much data and increased our knowledge of functional aspects of headwater streams. In the last 3 decades, we have studied stream Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 77 segments along longitudinal reaches spanning multiple stream orders (Grubaugh et al. 1997, Vannote et al. 1980). We have also made progress toward understanding how physical factors, such as local geomorphology and discharge, influence nutrient uptake, retention, and transformation, as well as how they affect detritus retention, food webs, and the functional structure of biota. However, we need to apply what we know about individual streams and longitudinal linkages to entire stream networks (Fisher 1997, Meyer and Wallace 2001). Such applications would inform the debate about mountaintop mining and the burial of small streams during that process. Studies of streams as entire networks are especially important because we are currently burying steams without knowing the basin-wide consequences of these practices. Headwater streams are exceptionally valuable sites of nutrient uptake and retention. Research had already demonstrated many biotic and abiotic effects of stream alteration. Science can help the public and policy-makers to answer several questions that have arisen: How much of an increase in downstream nutrients, as well as harmful chemicals in our water supplies, are we willing to accept as a result of buried headwater streams? Are we willing to accept the altered hydrology with the propensity to raise downstream flood peaks? These floods are associated with the flushing of organic matter, scouring of algal food resources, and enhanced drift of aquatic animals. The burial of headwater streams eliminates the linkages among forests, headwaters, and downstream segments. Complete biotic inventories are required for most, if not all, of the buried streams. It is obvious that, based on their invertebrate assemblages, some streams destined to be buried are currently of excellent quality. How much concern do we place on the loss—in perpetuity—of this biotic diversity and habitat? How many long-term, irrevocable cumulative effects to downstream rivers is the public willing to accept? Finally, once the environment has been degraded and the resources are diminished, can we maintain a reasonable quality of life? These important questions directly affect a substantial area of the Central Appalachians, and in many instances, decisions are being made without considering the consequences of our actions. Acknowledgments We appreciate the efforts of Dr. George Constantz and Mr. Ron Preston in organizing the Canaan Valley and its Environs Celebration and this special issue. We thank the editors and reviewers for editorial comments that improved this manuscript. Much of the information reported here was supported by grants from the National Science Foundation (Ecosystems Studies Program and Long-term Ecological Research) and the US Department of Agriculture Forest Service. We thank these agencies for their continued support of research on headwater streams. Literature Cited Allman, R.C. 1976. Canaan Valley and the Black Bear. McClain Printing Co., Parsons, WV. 118 pp. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 78 Bednarek, A.T. 2001. Undamming rivers: A review of the ecological impacts of dam removal. Environmental Management 27:803–814. Benfield, E.F., J.R. Webster, J.L. Tank, and J.J. Hutchens. 2001. Long-term patterns in leaf breakdown in response to watershed logging. International Review of Hydrobiology 86:467–474. Benke, A C. 1993. Concepts and patterns of invertebrate production in running waters. Proceedings of the International Association of Theoretical and Applied Limnology 25:15–38. Benke, A.C., and J.B. Wallace. 1980. Trophic basis of production among net-spinning caddisflies in a southern Appalachian stream. Ecology 61:108–118. Bolstad, P.V., and W.T. Swank. 1997. Cumulative impacts of land use on water quality in a southern Appalachian watershed. Journal of the American Water Resources Association 33:519–533. Booth, D.B., and C.R. Jackson. 1997. Urbanization of aquatic systems: Degradation thresholds, stormwater detection, and the limits of mitigation. Journal of the American Water Resources Association 33:1077–1090. Bormann, F.H., and G.E. Likens. 1979. Pattern and Process in a Forested Ecosystem. Springer-Verlag, New York, NY. 253 pp. Bunn, S.E., and A.H. Arthington. 2002. Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity. Environmental Management 30:492–507. Bushaw-Newton, K.L., and 15 others. 2002. An integrative approach towards understanding ecological responses to dam removal: The Manatawny Creek study. Journal of the American Water Resources Association 38:1581–1599. Carpenter, S.R., N.F. Caraco, D.L. Correll, R.W. Howarth, A.N. Sharpley, and V.H. Smith. 1998. Nonpoint pollution of surface waters with phosphorus and nitrogen. Ecological Applications 8:559–568. Chaloner, D.T., and M.S. Wipfli. 2002. Influence of decomposing Pacific salmon carcasses on macroinvertebrate growth and standing stock in southeastern Alaska streams. Journal of the North American Benthological Society 21:430–442. Chin, A., D.L. Harris, T.H. Trice, and J.L. Given. 2002. Adjustment of stream channel capacity following dam closure, Yegua Creek, Texas. Journal of the American Water Resources Association 88:1521–1531. Clarkson, R.B. 1964. Tumult on the Mountains: Logging in West Virginia—1770–1920. McClain Printing Co., Parsons, WV. 410 pp. Chung, K., J.B. Wallace, and J.W. Grubaugh. 1993. The impact of insecticide treatment on abundance, biomass, and production of litterbag fauna in a headwater stream: A study of pretreatment, treatment, and recovery. Limnologica 28:93–106. Cuffney, T.F., and J.B. Wallace. 1989. Discharge-export relationships in headwater streams: Influence of invertebrate manipulations and drought. Journal of the North American Benthological Society 8:331–341. Cuffney, T.F., J.B. Wallace, and G.J. Lugthart. 1990. Experimental evidence quantifying the role of benthic invertebrates in organic matter dynamics of headwater streams. Freshwater Biology 23:281–199. Cushing, C.E., K.W. Cummins, and G.W. Minshall (Eds.). 1995. River and Stream Ecosystems. Vol. 22: Ecosystems of the World. Elsevier, Amsterdam, The Netherlands. 817 pp. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 79 David, M.B., and L.E. Gentry. 2000. Anthropogenic inputs of nitrogen and phosphorus and riverine export for Illinois, USA. Journal of Environmental Quality 29:494–508. Doyle, M.W., E.H. Stanley, and J.M. Harbor. 2002. Geomorphic analogies for assessing probable channel response to dam removal. Journal of the American Water Resources Association 38:1567–1579. Duncan, S.H., R.E. Bilby, J.W. Ward, and J.T. Heffner. 1987. Transport of road-surface sediment through ephemeral stream channels. Water Resources Bulletin 23:113–119. Duncan, W.F.A., and M.A. Brusven. 1985. Energy dynamics of three low-order southeast Alaskan streams: Autochthonous production. Journal of Freshwater Ecology 3:115–166. Dynesius, M., and C. Nilsson. 1994. Fragmentation and flow regulation of river systems in the northern third of the world. Science 266:753–762. Eggert, S.L., and J.B. Wallace. 2003. Reduced detrital resources limit Pycnopsyche gentilis (Trichoptera: Limnephilidae) production and growth. Journal of the North American Benthological Society 22:388–400. Eggert, S.L., J.B. Wallace, J.L. Meyer, and J.R. Webster. 2012. Storage and export of organic matter in a headwater stream: Responses to long-term detrital manipulations. Ecosphere 3(9):75. Elmore, A.J., and S.S. Kaushal. 2008. Disappearing headwaters: Patterns of stream burial due to urbanization. Frontiers in Ecology and the Environment 6:308-312. Ensign, W.E., R.J. Stranger, and S.E. Moore. 1990. Summer food limitation reduces Brook and Rainbow Trout biomass in a southern Appalachian stream. Transactions of the American Fisheries Society 119:894–901. Finkenbine, J.K., J.W. Atwater, and D.S. Mavinic. 2000. Stream health after urbanization. Journal of the American Water Resources Association 36:1149–1160. Fisher, S.G. 1997. Creativity, idea generation, and the functional morphology of streams. Journal of the North American Benthological Society 16:305–318. Fisher, S.G., and G.E. Likens. 1973. Energy flow in Bear Brook, New Hampshire: An integrative approach to stream ecosystem metabolism. Ecological Monographs 43:421–439. Forman, R.T.T., and L.E. Alexander. 1998. Roads and their major ecological effects. Annual Review of Ecology and Systematics 29:207–231 Gende, S.M., and M.F. Willson. 2001. Passerine densities in riparian forests of southeast Alaska: Potential role of anadromous spawning salmon. Condor 103:624–629. Gende, S.M., R.T. Edwards, M.F. Willson, and M.W. Wipfli. 2002. Pacific salmon in aquatic and terrestrial ecosystems. BioScience 52:917–928. Gomi, T.R., C. Sidle, and J.S. Richardson. 2002. Understanding processes and downstream linkages of headwater systems. BioScience 52:905–916. Griffith, M.B., and S.A. Perry. 1991. Leaf-pack processing in two Appalachian Mountain streams draining catchments with different management histories. Hydrobiologia 220:247–254. Griffith, M.B., E.M. Barrows, and S.A. Perry. 1996. Effects of aerial application of diflubenzuron on emergence and flight of adult aquatic insects. Journal of Economic Entomology 89:442–446. Grubaugh, J.W., J.B. Wallace, and L.S. Houston. 1997. Production of benthic macroinvertebrate communities along a southern Appalachian river continuum. Freshwater Biology 37:581–596. Gurtz, M.E., and J.B. Wallace. 1984. Substrate-mediated response of stream invertebrates to disturbance. Ecology 65:1556–1569. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 80 Gurtz, M.E., J.R. Webster, and J.B. Wallace. 1980. Seston dynamics in southern Appalachian streams: Effects of clearcutting. Canadian Journal of Fisheries and Aquatic Sciences 37: 624–631. Hall, R.O., J.B. Wallace, and S.L. Eggert. 2000. Organic matter flow in stream food webs with reduced detrital resource base. Ecology 81:3445–3463. Hansen, W.F. 2001. Identifying stream types and management implications. Forest Ecology and Management 143:39–46. Harding, J.S., E.F. Benfield, P.V. Bolstad, G.S. Helfman, and E.B.D. Jones III. 1998. Stream biodiversity: The ghost of land use past. Proceedings of the National Academy of Sciences of the USA 95:14,843–14,847. Harding, J.S., R.G. Young, J.W. Hayes, K.A. Shearer, and J.D. Stark. 1999. Changes in agricultural intensity and river health along a river continuum. Freshwater Biology 42:345–357. Hart, D.D., T.E. Johnson, K.L. Bushaw-Newton, R.J. Horwitz, A.T. Bednarek, D.F. Charles, D.A. Kreeger, and D.J. Velinsky. 2002. Dam removal: Challenges and opportunities for ecological research and river restoration. BioScience 52:669–681. Helfield, J.M., and R.J. Naiman. 2001. Effects of salmon-derived nitrogen on riparian forest growth and implications for stream productivity. Ecology 82:2403–2409. Hilderbrand, G.V., T.A. Hanley, C.T. Robbins, and C.C. Schwartz. 1999. Role of Brown Bears (Ursus arctos) in the flow of marine nitrogen into a terrestrial ecosystem. Oecologia 121:546–550. Hoffman, R.S., P.D. Capel, and S.J. Larson. 2000. Comparison of pesticides in eight US urban streams. Environmental Toxicology and Chemistry 19:2249–2258. Hursh, C.R. 1951. Research in forest-streamflow relations. Unasy lva 5:3–9. Huryn, A.D., V.M. Butz Huryn, C.J. Arbuckle, and L. Tsomides. 2002. Catchment land use, macroinvertebrates, and detritus processing in headwater streams: Taxonomic richness versus function. Freshwater Biology 47:401–415. Hutchens, J.J., and E.F. Benfield. 2000. Effects of forest defoliation by the Gypsy Moth on detritus processing in southern Appalachian streams. American Midland Naturalist 143:397–404. Hutchens, J.J., and J.B. Wallace. 2002. Ecosystem linkages between southern Appalachian headwater streams and their banks: Leaf-litter breakdown and invertebrate assemblages. Ecosystems 5:80–91. Hynes, H.B.N. 1941. The taxonomy and ecology of the nymphs of British Plecoptera, with notes on the adults and eggs. Transactions of the Royal Entomological Society of London 91:459–557. Johnson, B.R., and J.B. Wallace. 2005. Bottom-up limitation of a stream salamander in a detritus-based food web. Canadian Journal of Fisheries and Aquatic Sciences 62:301–311. Jones, J.A., F.J. Swanson, B.C. Wemple, and K.U. Snyder. 2000. Effects of roads on hydrology, geomorphology, and disturbance patches in stream networks. Conservation Biology 14:76–85. Kemp, S.J., and J.R. Spotila. 1997. Effects of urbanization on Brown Trout (Salmo trutta), other fishes, and macroinvertebrates in Valley Creek, Valley Forge, Pennsylvania. American Midland Naturalist 138:55–68. Kochenderfer, J.N., and J.D. Helvey. 1987. Using gravel to reduce soil losses from minimum-standard forest roads. Journal of Soil and Water Conservation 42:46–50. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 81 Larson, G.L., and S.E. Moore. 1985. Encroachment of exotic Rainbow Trout into stream populations of native Brook Trout in the southern Appalachian mountains. Transactions of the American Fisheries Society 114:195–203. Lemly, A.D. 2008. Aquatic hazard of selenium pollution from coal mining. Pp. 167–183, In G.B. Fosdyke (Ed.). Coal Mining: Research, Technology, and Safety. Nova Science Publishers, Inc., New York, NY. 298 pp. Leopold, L.B. 1994. A View of the River. Harvard University Press, Cambridge, MA. 298 pp. Leopold, L.B., M.G. Wolman, and J.P. Miller. 1964. Fluvial Processes in Geomorphology. W.H. Freeman, San Francisco, CA. 522 pp. Liess, M., R. Schulz, M.H.D. Liess, B. Rother, and R. Kruzig. 1999. Determination of insecticide contamination in agricultural headwater streams. Water Research 33:239–247. Lohr, S.C., and J.L. West. 1992. Microhabitat selection by Brook and Rainbow Trout in a southern Appalachian stream. Transactions of the American Fisheries Society 121:729–736. Lugthart, G.J., and J.B. Wallace. 1992. Effects of disturbance on benthic functional structure and production in mountain streams. Journal of the North American Benthological Society 11:138–164. Lugthart, G.J., J.B. Wallace, and A.D. Huryn. 1990. Secondary production of chironomids communities in insecticide-treated and untreated headwater streams. Freshwater Biology 23:417–427. Menzel, R.G., and C.M. Cooper. 1992. Small impoundments and ponds. Pp. 389–420, In C.T. Hackney, S.M. Adams, and W.H. Martin (Eds.). Biodiversity of the Southeastern United States, Aquatic Communities. John Wiley, New York, NY. 779 p. Merrill, M.D. 2001. Local and watershed influences on stream fish biotic integrity in the upper Oconee watershed, Georgia, USA. M.Sc. Thesis, University of Georgia, Athens, GA. 237 pp. Meyer, J.L. 1990. A blackwater perspective on riverine ecosystems. BioScience 40:643–651. Meyer, J.L. 1994. The microbial loop in flowing waters. Microbial Ecology 28:195–199. Meyer, J.L., and C.M. Tate. 1983. The effects of watershed disturbance on dissolved organic carbon dynamics of a stream. Ecology 64:33–44. Meyer, J.L. and J.B. Wallace. 2001. Lost linkages and lotic ecology: Rediscovering small streams. Pp. 295–317, In M.C. Press, N.J. Huntly and S. Levin (Eds.). Ecology: Achievement and Challenge. Blackwell Science, Oxford, UK. 406 pp. Meyer, J.L., J.B. Wallace and S.L. Eggert. 1998. Leaf litter as a source of dissolved organic carbon in streams. Ecosystems 1:240–249. Meyer, J.L., D.L. Strayer, J.B. Wallace, S.L. Eggert, G.S. Helfman, and N.L. Leonard. 2007. The contribution of headwater streams to biodiversity in river networks. Journal of the Water Resources Association 43:86–103. Minshall, G.W., R.C. Petersen, K.W. Cummins, T.L. Bott, J.R. Sedell, C.E Cushing, and R.L. Vannote. 1983. Interbiome comparison of stream ecosystem dynamics. Ecological Monographs 53:1–25. Morse, J.C., B.P. Stark, and W.P. McCafferty. 1993. Southern Appalachian streams at risk: Implications for mayflies, stoneflies, caddisflies, and other aquatic biota. Aquatic Conservation: Marine and Freshwater Ecosystems 3:292–303. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 82 Morse, J.C., B.P. Stark, W.P. McCafferty, and K.J. Tennessen. 1997. Southern Appalachian and other southeastern streams at risk: Implications for mayflies, dragonflies and damselflies, stoneflies, and caddisflies. Pp. 17–42, In G.W. Benz and D.E. Collins (Eds.). Aquatic Fauna in Peril: The Southeastern Perspective. Special Publication 1, Southeastern Aquatic Research Institute. Lanz Design and Communications, Decatur, GA. 554 pp. Naiman, R.J., R.E. Bilby, D.E. Schindler, and J.M. Helfield. 2002. Pacific salmon, nutrients, and the dynamics of freshwater and riparian ecosystems. Ecosystems 5:399–417. Nakano, S., and M. Murakami. 2001. Reciprocal subsidies: Dynamic interdependence between terrestrial and aquatic food webs. Proceedings of the National Academy of Sciences of the USA 98:166–170. Nelson, J.E., and D.B. Booth. 2002. Sediment sources in an urbanizing, mixed land-use watershed. Journal of Hydrology 264:51–68. Newbold J.D., D.C. Erman, and K.B. Roby. 1980. Effects of logging on macroinvertebrates in streams with and without buffer strips. Canadian Journal of Fisheries and Aquatic Sciences 37:1076–1085. Nislow, K.H., F.J. Magilligan, H. Fassnacht, D. Bechtel, and A. Ruesink. 2002. Effects of dam impoundments on the flood regime of natural floodplain communities in the Upper Connecticut River. Journal of the American Water Resources Association 38:1533–1548. Noel, D.S., C.W. Martin, and C.A. Federer. 1986. Effects of forest clearcutting in New England on stream macroinvertebrates and periphyton. Environmental Management 10:661–670. Orwig, D.A. 2002. Ecosystem to regional impacts of introduced pests and pathogens: Historical context, questions, and issues. Journal of Biogeography 29:1471–1474. Palmer, M.A., E.S. Bernhardt, W.H. Schlesinger, K.N. Eshleman, E. Foufoula-Georgiou, M.S. Hendryx, A.D. Lemly, G.E. Likens, O.L. Loucks, M.E. Power, P.S. White, and P.R. Wilcock. Mountaintop-mining consequences. Science 327:148–149. Paul, M.J., and J.L. Meyer. 2001. Streams in the urban landscape. Annual Review of Ecology and Systematics 32:333–365. Petersen, R.C., and K.W. Cummins. 1974. Leaf processing in a woodland stream. Freshwater Biology 4:343–368. Peterson, B.J., W.M. Wollheim, P.J. Mulholland, J.R. Webster, J.L. Meyer, J.L. Tank, E. Marti, W.B. Bowden, H.M. Valett, A.E. Hershey, W.H. McDowell, W.K. Dodds, S.K. Hamilton, S. Gregory, and D.D. Morrall. 2001. Control of nitrogen export from watersheds by headwater streams. Science 292:86–90. Pizzuto, J. 2002. Effects of dam removal on river form and process. BioScience 52:683–691. Pond, G.J., M.E. Passmore, F.A. Borsuk, L. Reynolds, and C.J. Rose. 2008. Downstream effects of mountaintop coal mining: Comparing biological conditions using familyand genus-level macroinvertebrate bioassessment tools. Journal of the North American Benthological Society 27:717–737. Richardson, J.S. 1991. Seasonal food limitation of detritivores in a montane stream: An experimental test. Ecology 72:873–887. Richardson, J.S. 2000. Life beyond salmon streams: Communities of headwaters and their role in drainage networks. Pp. 473–476, In L.M. Darling (Ed.). Proceedings of a Conference on the Biology and Management of Species and Habitats at Risk, 15–19 Feb 1999, Vol. 2. BC Ministry of Environment, Lands and Parks, Victoria, BC and University College of the Cariboo, Kamloops, BC. 520 pp. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 83 Roback, S.S., and J.W. Richardson. 1969. The effects of acid mine drainage on aquatic insects. Proceedings of the Academy of Natural Sciences of Philadelphia 121:81–107. Rose, S., and N.E. Peters. 2001. Effects of urbanization on streamflow in the Atlanta area (Georgia, USA): A comparative hydrological approach. Hydrological Processes 15:1441–1457. Rosi-Marshall, E., and J.B. Wallace. 2002. Invertebrate food webs along a stream resource gradient. Freshwater Biology 47:129–141. Roy, A.H., A.D. Rosemond, M.J. Paul, D.S. Leigh, and J.B. Wallace. 2003. Stream macroinvertebrate response to catchment urbanization (Georgia, US). Freshwater Biology 48:329–346. Sabo, J.L., and M.E. Power. 2002. Numerical response of lizards to aquatic insects and short-term consequences for terrestrial prey. Ecology 83:3023–3036. Samuel, D.E., J.R. Stauffer, and C.H. Hocutt (Eds.). 1978. Surface mining and fish/ wildlife needs in the eastern United States. US Fish and Wildlife Service, Office of Biological Services FWS/OBS-78/81. 386 pp. Sanzone, D.M. 2001. Linking communities across ecosystem boundaries: The influence of aquatic subsidies on terrestrial predators. Ph.D. Dissertation. University of Georgia, Athens, GA. 263 pp. Smock, L.A., and C.M. MacGregor. 1988. Impact of the American chestnut blight on aquatic shredding macroinvertebrates. Journal of the North American Benthological Society 7:212–221. Snyder, C.D., J.A. Young, D.P. Lemarié, and D.R. Smith. 2002. Influence of Eastern Hemlock (Tsuga canadensis) forests on aquatic invertebrate assemblages in headwater streams. Canadian Journal of Fisheries and Aquatic Sciences 59:262–275. Snyder, C.D., J.A. Young, and B.M. Stout III. 2006. Aquatic habitats of Canaan Valley, West Virginia: Diversity and environmental threats. Northeastern Naturalist 13:333–352. Stanford, J.A., and J.V. Ward. 2001. Revisiting the serial discontinuity concept. Regulated Rivers: Research and Management 17:303–310. Stanley, E.H., and M.W. Doyle. 2002. A geomorphic perspective on nutrient retention following dam removal. BioScience 52:693–701. Statzner, B., and B. Higler. 1985. Questions and comments on the river continuum concept. Canadian Journal of Fisheries and Aquatic Sciences 42:1038–1044. Stepenuck, K.F., R.L. Crunkilton, and L.Z. Wang. 2002. Impacts of urban land use on macroinvertebrate communities in southeastern Wisconsin streams. Journal of the American Water Resources Association 38:1041–1051. Stone, M.K., and J.B. Wallace. 1998. Long-term recovery of a mountain stream from clear-cut logging: The effects of forest succession on benthic invertebrate community structure. Freshwater Biology 39:141–169. Suberkropp, K., and J.B. Wallace. 1992. Aquatic hyphomycetes in insecticide-treated and untreated streams. Journal of the North American Benthological Society 11:165–171. Swank, W.T., J.M. Vose, and K.J. Elliott. 2001. Long-term hydrologic and water-quality responses following commercial clearcutting of mixed hardwoods on a southern Appalachian catchment. Forest Ecology and Management 143:163–178. Swift, L.W., Jr. 1983. Duration of stream temperature increases following forest cutting in the southern Appalachian Mountains. Pp. 273–275, In A.I. Johnson and R.A. Clark (Eds.). Proceedings of the International Symposium on Hydrometerology, Denver, CO, 13-17 June 1982. American Water Resources Association, Bethesda, MD. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 84 Swift, L.W., Jr. 1984a. Soil losses from roadbeds and cut and fill slopes in the southern Appalachian Mountains. Southern Journal of Applied Forestry 8:209–216. Swift, L.W., Jr. 1984b. Gravel and grass surfacing reduce soil loss from mountain roads. Forest Science 30:657–670. Swift, L.W., Jr. 1988. Forest access roads: Design, maintenance, and soil loss. Pp. 313– 324, In W.T. Swank and D.A. Crossley, Jr. (Eds.). Forest Hydrology and Ecology at Coweeta. Springer-Verlag, New York, NY. 469 pp. Tank, J.L., and J.R. Webster. 1998. Interaction of substrate availability and nutrient distribution on wood biofilm development in streams. Ecology 79:216 8–2179. Tank, J.L., J.R. Webster, and E.F. Benfield. 1998. Effect of leaf-litter exclusion on microbial enzyme activity associated with wood biofilms in streams. Journal of the North American Benthological Society 17:95–103. Tarter, D.C. 1976. Limnology in West Virginia: A Lecture and Laboratory Manual. Marshall University Bookstore, Huntington, WV. 249 pp. Tebo, L.B., Jr. 1955. Effects of siltation, resulting from improper logging, on the bottom fauna of a small trout stream in the southern Appalachians. Progressive Fish-Culturist 17:64–70. Trimble, G.R., Jr. 1977. A history of the Fernow Experimental Forest and the Parsons Timber and Watershed Laboratory. General Technical Report NE-28. USDA Forest Service, Broomall, PA. 46 pp. Trimble, S.W. 1997. Contribution of stream channel erosion to sediment yield from an urbanizing watershed. Science 278:1442–1444. US Fish and Wildlife Service. 1998. Permitted stream losses due to valley filling in Kentucky, Pennsylvania, Virginia, and West Virginia: A partial inventory. Pennsylvania Ecological Services Field Office, State College, PA. 12 pp. Vannote, R.L., and B.W. Sweeney. 1980. Geographic analysis of thermal equilibria: A conceptual model for evaluating the effect of natural and modified thermal regimes on aquatic insect communities. American Naturalist 115:667–695. Vannote, R.L., G.W. Minshall, K.W. Cummins, J.R. Sedell, and C.E. Cushing. 1980. The river continuum concept. Canadian Journal of Fisheries and Aquatic Sciences 37:130–137. Waldron, M.C., and J.B. Wiley. 1996. Water quality and processes affecting dissolved oxygen concentrations in the Blackwater River, Canaan Valley, West Virginia. Water- Resources Investigations Report 95-4142, US Geological Survey, Charleston, WV. 85 pp. Wallace, J.B., and M.E. Gurtz. 1986. Response of Baetis mayflies (Ephemeroptera) to catchment logging. American Midland Naturalist 115:25–41. Wallace, J.B., and J.J. Hutchens. 2000. Effects of invertebrates in lotic ecosystem processes. Pp. 73–96, In D.C. Coleman and P.E. Hendrix (Eds.). Invertebrates as Webmasters in Ecosystems. CABI Publishing, Oxon, UK. 336 p. Wallace, J.B., G.J. Lugthart, T.F. Cuffney, and G.A. Schurr. 1989. The influence of repeated insecticidal treatments on drift and benthos of a headwater stream. Hydrobiologia 179:135–147. Wallace, J.B., T.F. Cuffney, J.R. Webster, G.J. Lugthart, K. Chung, and B.S. Goldowitz. 1991a. Export of fine particulate organic matter from headwater streams: Effects of season, extreme discharge, and invertebrate manipulation. Limnology and Oceanography 36:670–682. Wallace, J.B., A.D. Huryn, and G.J. Lugthart. 1991b. Colonization of a headwater stream during three years of seasonal insecticidal applications. Hydrobiologia 211:54–76. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 85 Wallace, J.B., J.R. Webster, and R.L. Lowe. 1992. High-gradient streams of the Appalachians. Pp. 133–190, In C.T. Hackney, S. Marshall Adams, and W.H. Martin (Eds.). Biodiversity of Southeastern United States, Aquatic Communities. John Wiley and Sons, New York, NY. 779 pp. Wallace, J.B., M.R. Whiles, S. Eggert, T.F. Cuffney, G.J. Lugthart, and K. Chung. 1995. Long-term dynamics of coarse particulate organic matter in three Appalachian Mountain streams. Journal of the North American Benthological Society 14:217–232. Wallace, J.B., S.L. Eggert, J.L. Meyer, and J.R. Webster. 1997. Multiple trophic levels of a forest stream linked to terrestrial litter inputs. Science 277:102–104. Wallace, J.B., S.L. Eggert, J.L. Meyer, and J.R. Webster. 1999. Effects of resource limitation on a detrital-based ecosystem. Ecological Monographs 69:409–442. Wallace, J.B., J.R. Webster, S.L. Eggert, J.L. Meyer, and E.R. Siler. 2001. Large woody debris in a headwater stream: Long-term legacies of forest disturbance. International Review of Hydrobiology 86:501–513. Walser, C.A., and H.L. Bart. 1999. Influence of agriculture on in-stream habitat and fish community structure in Piedmont watersheds of the Chattahoochee River system. Ecology of Freshwater Fish 8:237–246. Wang, L., J. Lyons, P. Kanehl, R. Bannerman, and E. Emmons. 2000. Watershed urbanization and changes in fish communities in southeastern Wisconsin streams. Journal of the American Water Resources Association 36:1173–1189. Wang, L.Z., J. Lyons, and P. Kanehl. 2001. Impacts of urbanization on stream habitat and fish across multiple spatial scales. Environmental Management 28 :255–266. Ward, J.D., and P.A. Mistretta. 2002. Impact of pests on forest health. Pp. 403–428, In D.N. Wear and J.G. Greis (Eds.). Southern Forest Resource Assessment. General Technical Report SRS-53, USDA Forest Service, Southern Research Station, Asheville, NC. 635 pp. Waters, T.F. 1995. Sediment in Streams: Source, Biological Effects, and Control. American Fisheries Society, Bethesda, MD. 251 pp. Wear, D.N. 2002. Land use. Pp. 153-173, In D.N. Wear and J.G. Greis (Eds.). Southern Forest Resource Assessment. General Technical Report SRS-53, USDA Forest Service, Southern Research Station, Asheville, NC. 635 pp. Weaver, L.A., and G.C. Garman. 1994. Urbanization of a watershed and historical changes in a stream fish assemblage. Transactions of the American Fisheries Society 123:162–172. Webster, J.R., and S.W. Golladay. 1984. Seston transport in streams at Coweeta Hydrologic Laboratory, North Carolina, USA. Proceedings of the International Association of Theoretical and Applied Limnology 22:1911–1919. Webster, J.R., and J.L. Meyer (Eds.). 1997. Stream organic matter budgets. Journal of the North American Benthological Society 16:3–161. Webster J.R., M.E. Gurtz, J.J. Hains, J.L. Meyer, W.T. Swank, J.B. Waide, and J.B. Wallace. 1983. Stability of stream ecosystems. Pp. 355–395, In J.R. Barnes and G.W. Minshall (Eds.). Stream Ecology. Plenum Press, New York, NY. 399 pp. Webster, J.R., J.B. Wallace, and E.F. Benfield. 1995. Organic processes in streams of the eastern United States. Pp. 103–164, In C.E. Cushing, G.W. Minshall, and K.W. Cummins (Eds.). River and Stream Ecosystems (Ecosystems of the World, Vol. 22). Elsevier Science, Amsterdam, The Netherlands. 817 pp. Southeastern Naturalist J.B. Wallace and S.L. Eggert 2015 Vol. 14, Special Issue 7 86 Webster, J.R., J.L. Tank, J.B. Wallace, J.L. Meyer, S.L. Eggert, T.P. Ehrman, B.R. Ward, B.L. Bennett, P.F. Wagner, and M.E. McTammany. 2000. Effects of litter exclusion and wood removal on phosphorus and nitrogen retention in a forest stream. Proceedings of the International Association of Theoretical and Applied Limnology 27:1337–1340. Webster, J.R., K. Morkeski. C.A. Wojculewski, B.R. Niederlehner, E.F. Benfield, and K.J. Elliott. 2012. Effects of hemlock mortality on streams in the southern Appalachian Mountains. American Midland Naturalist 168:112–131. Wemple, B.C., F.J. Swanson, and J.A. Jones. 2001. Forest roads and geomorphic process interactions, Cascade Range, Oregon. Earth Surface Processes and Landforms 26:191–204. Whiles, M.R., and J.B. Wallace. 1992. First-year benthic recovery of a headwater stream following an insecticide-induced disturbance. Freshwater Biology 28:81–91. Whitworth, W.E., and R.J. Strange. 1983. Growth and production of sympatric Brook and Rainbow Trout in an Appalachian stream. Transactions of the American Fisheries Society 112:469–475. Winter, J.G., and H.C. Duthie. 2000. Export coefficient modeling to assess phosphorus loading in an urban watershed. Journal of the American Water Resources Association 36:1053–1061. Wipfli, M.S., and D.P. Gregovich. 2002. Export of invertebrates and detritus from fishless headwater streams in southeastern Alaska: Implications for downstream salmonid production. Freshwater Biology 47:957–969. Wipfli, M.S., J. Hudson, and J. Caouette. 1998. Influence of salmon carcasses on stream productivity: Response of biofilm and benthic macroinvertebrates in southeastern Alaska, USA. Canadian Journal of Fisheries and Aquatic Sciences 56:1600–1611. Wolf, Ph. 1956. Utdikad Civilisation (Drained Civilization). Gleerups, Malmo, Sweden. 104 pp.