Effects of shoreline development on the nearshore environment in large deep oligotrophic lakes

Abstract

Summary 1. In large deep oligotrophic lakes, the shallow nearshore waters may provide the most important habitat for animals to feed and breed, and it is this area of the lake where humans are most likely to have initial impacts as the shoreline is developed. Nutrients in fertilizers, sediments and sewage effluents are likely to be rapidly intercepted by nearshore algae at the lake edge, having heterogeneous effects nearshore before offshore effects are noted. 2. Here we examined the spatially explicit effects of residential development on nearshore periphyton communities in three large deep oligotrophic lakes that have all experienced modest residential development in the Pacific Northwest of the United States. We demonstrate that substantial nearshore changes in the basal food web are detectable even with low levels of shoreline development. These changes can potentially affect whole‐lake food web dynamics. 3. For our primary study site (Lake Crescent, Washington, USA), we found that algal biomass and accumulation of detritus were higher at developed sites. In addition, both macroinvertebrate and periphyton communities exhibited a shift in composition with more detritivores and filamentous green algae at developed sites. These differences were more pronounced during the spring than at other times of year. 4. A complementary investigation of field patterns in Priest Lake and Lake Pend Oreille (Idaho, USA) suggested that, although spatial and temporal patterns were idiosyncratic, indicators of productivity and the presence of filamentous green algae were generally higher at developed sites across lakes. 5. Stable isotope signatures and water column nutrients were not useful in distinguishing developed and undeveloped sites, increasing the potential usefulness of periphyton monitoring during early stages of lake development. 6. A laboratory investigation suggested that common macroinvertebrate grazers assimilated a much greater proportion of diatoms than the filamentous green algae that are associated with fertilization at developed sites. 7. These findings have at least two clear implications: (i) periphyton may be used to detect human impacts before disturbance is evident in offshore monitoring programmes and (ii) nearshore impacts in response to modest residential development have the potential to disrupt lake food web dynamics.

Ecology of freshwater shore zones

“…In natural shore zones, nutrient inputs are controlled largely by the geological structure of the shore zone and its surroundings, but modern shore zones often are dominated by human inputs from sewage, urban and agricultural runoff, and atmospheric deposition. Even small changes in the inputs of phosphorus and nitrogen can affect the species composition and productivity of macrophytes and algae (e.g., Bertness et al 2002;Hecky et al 2004;Boers and Zedler 2008;Rosenberger et al 2008). …”

The challenge of self-enhancement bias for educational programs designed to encourage natural shorelines

“…Fortunately a variety of actions are available to property owners to mitigate the impact of development, such as selectively planting native vegetation or allowing remnant natural vegetation to grow in the near-shore zone * Corresponding author: amato@wisc.edu of their property and the littoral zone along it. The benefits of more natural shorelines may include increased plant diversity (Elias and Meyer 2003), reduced algae (Rosenberger et al 2008), higher numbers of animals such as frogs and native birds (Lindsay et al 2002, Woodford and Meyer 2003, Henning and Remsburg 2009, as well as larger and more abundant fish populations (Radomski andGoeman 2001, Helmus andSass 2008).…”

Assessing local and landscape patterns of residential shoreline development in Michigan lakes

“…In addition, human population growth and urbanization of rural areas have increased development pressure on lakes, and there is growing concern Understanding the consequences of residential development is therefore critical for understanding the ecology of lake ecosystems. A growing number of studies have found negative relationships between lakeshore development and water quality (Moore et al 2003); habitat structure (Christensen et al 1996, Jennings et al 2003, Francis and Schindler 2006; and population dynamics and community structure of primary producers (Radomski and Goeman 2001, Jennings et al 2003, Rosenberger et al 2008, macroinvertebrates (Banziger 1995, Brauns et al 2007, and fishes (Bryan and Scarneccia 1992, Jennings et al 1999, Schindler et al 2000, Radomski and Goeman 2001, Scheuerell and Schindler 2004, Sass et al 2006, Wagner et al 2006. These comparative studies provide much needed information linking shoreline development and key lake characteristics.…”