An Ecologically Based Approach to Identifying Restoration Priorities in an Acid‐Impacted Watershed

Abstract The extent of impairment to some Appalachian water-sheds from acid precipitation is so extreme that watershedscale analytical tools are needed to help guide cost-effective management decisions. The objective of thisstudy was to develop a measure of the functional value ofstreams as potential areas for juvenile Brook trout recruit-ment. This measure, which we term ‘‘weighted potentialrecruitment area’’ (WPRA), is a function of the expectedBrook trout spawning intensity and juvenile survivorship.Estimates of WPRA for each stream segment were thenused to identify restoration priorities and optimal restora-tion programs in the upper Shavers Fork watershed inWest Virginia, U.S.A. Using this approach, we deter-mined that the watershed has lost nearly 80% of its his-toric juvenile recruitment potential as a result of acidprecipitation. We also determined that of the 145 streamsegments in the watershed, eight critical stream segmentsaccount for nearly 20% of the loss. The costs and eco-logical beneﬁts of a series of ﬁve alternative restorationprograms were then assessed using an ArcGIS model(Environmental Systems Research Institute, Redlands,CA, U.S.A.). This approach identiﬁed two ‘‘optimal’’ al-ternatives: (1) a low-cost, moderate-beneﬁt approach thatwould use existing rail access to treat acidiﬁcation in threecritical headwater locations and (2) a high-cost, high-beneﬁt approach that would use aerial limestone applica-tion to treat numerous acidic tributaries near their source.The measure of stream ecological value that we developedwas effective in identifying critical restoration prioritiesand optimal restoration strategies in this watershed. Asimilar procedure could be used to guide watershed resto-ration decisions throughout the Appalachian region.Key words: acid precipitation, Appalachian streams,Brook trout, cost–beneﬁt analysis, restoration priorities.IntroductionAcid precipitation is ubiquitous in the eastern UnitedStates, and it has had devastating effects on many aquaticecosystems (Wigington et al. 1996). This is especially truein the high-elevation watersheds of the central Appala-chian Mountains. In fact, it is estimated that more than25% of Brook trout (Salvelinus fontinalis) streams in WestVirginia have been impaired by acid precipitation. Highloadings of acidity from precipitation reduce bufferingcapacity in surrounding soils, leach nutrients from water-sheds (Lajewski et al. 2003), and lead to decreased pH andincreased concentrations of dissolved aluminum in surfacewaters (Wigington & Dewalle 1996; Fitzhugh et al. 1999).Abrupt changes in surface water chemistry typically havesevere impacts on aquatic communities. Diverse, highlyproductive benthic invertebrate communities are con-verted to communities comprised of only a few acidophilictaxa (Kobuszewski & Perry 1993; Rosemond et al. 1993).In addition, entire ﬁsh communities can be lost from acidi-ﬁed streams. Numerous studies have shown that acute de-pressions in stream pH and increased levels of inorganic,monomeric aluminum cause severe reductions in ﬁshsurvivorship and growth, especially in early life stages(Menendez 1976; Sharpe et al. 1987; Fiss & Carline 1993;Baker et al. 1996; Van Sickle et al. 1996; Heard et al. 1997).The only long-term solution to the acidiﬁcation problemis through reduction of nitrate and sulfate emissions fromvehicles and coal-ﬁred power plants. However, in an effortto quickly recover lost ecosystem values, state and federalagencies spend considerable sums of money each yeartreating acidiﬁed streams with limestone (Zurbuch 1984).Although there are numerous methods for treating acidicsystems, the most common approach is to add large quanti-ties of limestone sand directly to impacted streams. Thisapproach has proven successful, especially in poorly buff-ered watersheds of the central Appalachians (Ivahnenkoet al. 1988; Downey et al. 1994; Clayton & Menendez 1996;Menendez et al. 1996; Clayton et al. 1998; Hudy et al.2000). Various studies have determined that regular lime-stone additions to acidiﬁed streams can dramatically im-prove water quality and result in the recovery of diverseinvertebrate and ﬁsh communities. In addition to beinghighly effective, this approach is relatively inexpensiveas long as there is existing road access within affectedwatersheds.Currently, two important logistical problems limit ourability to effectively manage and recover acid-impacted