Elsevier

Ecological Indicators

Volume 10, Issue 2, March 2010, Pages 303-310
Ecological Indicators

Aquatic degradation in shallow coastal plain lakes: Gradients or thresholds?

https://doi.org/10.1016/j.ecolind.2009.06.001Get rights and content

Abstract

The establishment of introduced species in aquatic and wetland habitats is often associated with human-related environmental degradation. In the blackwater streams of the New Jersey Pinelands, the presence of nonnative species drives the relationship between community composition and watershed disturbance associated with developed land and upland agriculture. Most Pinelands lakes are shallow, artificial stream impoundments. In this study, we determined if land-use gradients or thresholds were associated with the presence of nonnative-herbaceous-plant, woody-plant, fish, and anuran species in 30 Pinelands stream impoundments. Correlation and regression analyses indicated that the response of all four taxonomic groups to watershed disturbance was an increase in the number of nonnative species and the proportion of total species richness represented by nonnative species. Native-anuran richness decreased along the watershed-disturbance gradient. We found both linear and nonlinear responses when relating species-richness attributes to the percentage of altered land (combined percentage of upland agriculture and developed land) in the associated watersheds, but the nonlinear responses cannot be considered land-use-related degradation-threshold responses. The breaks in the regression lines describing the relationship between the percentage of total species richness represented by nonnative plants and fish and altered land in our Pinelands watersheds did not represent a degradation threshold because, with the exception of the percentage of total species richness represented by nonnative-anuran species, a progressive decline in aquatic integrity was observed before the break points. Kruskal–Wallis ANOVA revealed significant differences in species-richness attributes only among stream impoundments with contrasting altered-land profiles, providing further evidence that aquatic degradation was progressive. Logistic regression identified the point along the watershed-disturbance gradient at which the probability of encountering nonnative bullfrogs was greater than that for native carpenter frogs.

Introduction

The establishment of introduced species in aquatic and wetland habitats is often associated with human-related environmental degradation (Moyle, 1973, Moyle, 1986, Ehrenfeld, 1983, Ehrenfeld and Schneider, 1991, Ehrenfeld and Schneider, 1993, Moyle and Light, 1996, Ashton and Mitchell, 1989, Owen, 1999, Galatowitsch et al., 2000, Green and Galatowitsch, 2002, Marchetti et al., 2004, Zedler and Kercher, 2004, Burton et al., 2005). The concept of degradation thresholds has been used to describe the level of urbanization and associated impervious surface that results in stream impairment (Arnold and Gibbons, 1996, May et al., 1997, Paul and Meyer, 2001, Gergel et al., 2002, Stepenuck et al., 2002). The concept is valid in areas dominated by urban-land use, however it fails to account for the effect of agriculture on the ecological integrity of surface waters in areas with mixed-land uses since both urban land and agriculture can result in water-quality degradation (Johnson et al., 1997, Carpenter et al., 1998, Herlihy et al., 1998, Rhodes et al., 2001) and associated changes in the composition of aquatic communities (Lenat and Crawford, 1994, Wang et al., 1997, Waite and Carpenter, 2000). In the New Jersey Pinelands, the extent of both developed land and upland agriculture must be considered to adequately explain variations in stream-water quality (Conway, 2007, Zampella et al., 2007). Ten-percent altered land, defined as the percentage of developed land and upland agriculture in a drainage basin, has been described as the threshold at which a significant deviation from reference-site water-quality conditions occurred in a major Pinelands watershed (Zampella et al., 2007).

Although the relationship between the presence of nonnative species and aquatic degradation associated with upland-agricultural and developed-land uses is well documented in the blackwater streams of the New Jersey Pinelands (Morgan and Philipp, 1986, Zampella and Laidig, 1997, Zampella and Bunnell, 1998, Zampella and Bunnell, 2000, Zampella et al., 2001, Bunnell and Zampella, 2008), the land-use-related degradation threshold at which the occurrence of nonnative species might occur has not been established. The purpose of this paper is to determine if altered-land-use gradients or thresholds are associated with the presence of nonnative plants, fish, and anurans in Pinelands stream impoundments.

Section snippets

Land use and study-site selection

Most Pinelands lakes are shallow, artificial stream impoundments that were created for sawmills, ironworks, papermaking, and cranberry production (Patrick et al., 1979, Wacker, 1979). We selected 30 impoundments that represented a range of watershed conditions characterized by the percentage of developed land and upland-agricultural land (Fig. 1). Mean lake area (±1 SD) was 16.2 (±11.6) ha. Land-use/land-cover and impervious-surface profiles for watersheds associated with the impoundment were

Water quality

For pH and specific conductance, medians for the 2003–2005 sampling period at all 30 impoundments ranged from 4.1 to 6.8 and 30.2 to 215 μS cm−1, respectively (Fig. 2). Both pH (r = 0.85, p < 0.001) and specific conductance (r = 0.75, p < 0.001) were positively correlated with a disturbance gradient represented by the percentage of altered land in a watershed.

Shoreline habitats

Mean nearshore-water depth ranged from 21 to 60 cm and averaged 41.5 (±9.0 SD) cm. Sediments other than sand or mud (muck or silt) were rarely

Discussion

The association between land-use change and biological invasions is a global phenomenon (Vitousek et al., 1997, Dukes and Mooney, 1999). Although land-use change has been implicated in the occurrence of nonnative species in wetland and aquatic communities in the Pinelands and elsewhere, the threshold at which such invasions occur is not well understood. The purpose of this paper was to determine if altered-land-use gradients or thresholds are associated with the presence of nonnative plants,

Acknowledgements

Jennifer Ciraolo and Kimberly Spiegel assisted with various aspects of the study, including the collection of water-quality samples and data entry. This article is based on a report submitted to the U.S. Environmental Protection Agency. Funding for the study was provided by a grant from the U.S. Environmental Protection Agency (Wetlands Protection State Development Grant CD98237801-0) with additional funding from the National Park Service and the Pinelands Commission. The views and conclusions

References (60)

  • P.J. Ashton et al.

    Aquatic plants: patterns and modes of invasion, attributes of invading species and assessment of control programmes

  • D.B. Booth et al.

    Forest cover, impervious-surface area, and the mitigation of stormwater impacts

    Journal of the American Water Resources Association

    (2002)
  • J.F. Bunnell et al.

    Native fish and anuran assemblages differ between impoundments with and without non-native centrarchids and Bullfrogs

    Copeia

    (2008)
  • M.L. Burton et al.

    Riparian woody plant diversity and forest structure along an urban-rural gradient

    Urban Ecosystems

    (2005)
  • S.R. Carpenter et al.

    Nonpoint pollution of surface waters with phosphorus and nitrogen

    Ecological Applications

    (1998)
  • C.L. Dow et al.

    Specific conductance and pH as indicators of watershed disturbance in streams of the New Jersey Pinelands, USA

    Environmental Management

    (2000)
  • J.G. Ehrenfeld et al.

    Chamaecyparis thyoides wetlands and suburbanization: effects on hydrology, water quality and plant community composition

    Journal of Applied Ecology

    (1991)
  • J.G. Ehrenfeld et al.

    Responses of forested wetland vegetation to perturbations of water chemistry and hydrology

    Wetlands

    (1993)
  • S.M. Galatowitsch et al.

    The vegetation of wet meadows in relation to their land-use

    Environmental Monitoring and Assessment

    (2000)
  • S.E. Gergel et al.

    Landscape indicators of human impacts to riverine systems

    Aquatic Sciences

    (2002)
  • H.A. Gleason et al.

    Manual of vascular plants of northeastern United States and adjacent Canada

    (1991)
  • E.K. Green et al.

    Effects of Phalaris arundinacea and nitrate-N addition on the establishment of wetland plant communities

    Journal of Applied Ecology

    (2002)
  • R.W. Hastings

    The fishes of the Mullica River, a naturally acid water system of the New Jersey Pine Barrens

    Bulletin of the New Jersey Academy of Science

    (1984)
  • A.T. Herlihy et al.

    The relationship between stream chemistry and watershed land cover data in the Mid-Atlantic Region, U.S.

    Water, Air, and Soil Pollution

    (1998)
  • L.B. Johnson et al.

    Landscape influences on water chemistry in midwestern stream ecosystems

    Freshwater Biology

    (1997)
  • R.D. Klein

    Urbanization and stream quality impairment

    Water Resources Bulletin

    (1979)
  • E.K. Kratzer et al.

    Macroinvertebrate distribution in relation to land use and water chemistry in New York City drinking-water-supply watersheds

    Journal of the North American Benthological Society

    (2006)
  • D.R. Lenat et al.

    Effects of land use on water quality and aquatic biota of three North Carolina Piedmont streams

    Hydrobiologia

    (1994)
  • R.D. Lopez et al.

    Ecological relationships between landscape change and plant guilds in depressional wetlands

    Landscape Ecology

    (2002)
  • M.P. Marchetti et al.

    Fish invasions in California watersheds: testing hypotheses using landscape patterns

    Ecological Applications

    (2004)
  • View full text