Ecosystem Services Provided by Freshwater Benthos

Alan P. Covich, Katherine C. Ewel, Robert O. Hall, Jr., Paul S. Giller, Willem Goedkoop, and David M. Merritt

The concept of ecosystem goods and services (Daily 1997; Heal 2000; Brismar 2002) conveys how natural processes such as biomass production and nutrient cycling are essential to the Earth's capacity for sustaining human populations. Here we examine how species diversity and ecosystem processes, which supply these goods and services to human societies, are mediated by sediment- or bottom-dwelling (benthic) organisms in fresh waters. Benthic invertebrates, microbes, and aquatic plants are widely distributed in fresh waters. Their ecology is well understood in many temperate-zone regions and the diversity of freshwater benthic communities is broadly documented (Bronmark & Hansson 1998; Giller & Malmqvist 1998; Thorp & Covich 2001). This biota includes some species that are widespread, functional generalists and others that are restricted in their distributions and are functionally specialized.

Sediment-dwelling plants and invertebrates provide numerous critical ecosystem services in fresh waters (Ewel 1997; Covich et al. 1999), yet economic valuation of associated ecosystem functions is rarely measured other than in shellfisheries production (Carpenter & Turner 2000; Odum & Odum 2000). What are the values of nonmar-ket goods and services derived from a lake or river or wetland? Relationships between species diversity, water resource allocations, and freshwater ecosystem services are being evaluated by ecologists and economists (Loomis 2000; Daily & Ellison 2002; National Research Council in press). Moreover, benthic biologists are beginning to determine how the loss of different species affects freshwater ecosystem functioning (Wall et al. 2001); to date, however, these experiments have primarily focused on small-scale, short-term studies of relatively few species (Giller et al. 2004; Covich et al. in press). Vulnerability of ecosystem services is increasing because of the elimination of many fresh-

The authors would like to acknowledge Nina Caraco for her contributions to this chapter.

Fresh Water Ecosystem Diagram

Figure 3.1. Schematic overview of a functional food web showing the linkages between food web processes and services provided by sediment and above-surface biota in freshwater ecosystems. Small black arrows indicate pathways for nutrient uptake and cycling from sediment-dwelling species to those in the open waters. Large gray arrows indicate major nutrient sources (inputs) and resulting ecosystem services (outputs) from biological processing in lakes and streams. FPOM = Fine Particulate Organic Matter.

Figure 3.1. Schematic overview of a functional food web showing the linkages between food web processes and services provided by sediment and above-surface biota in freshwater ecosystems. Small black arrows indicate pathways for nutrient uptake and cycling from sediment-dwelling species to those in the open waters. Large gray arrows indicate major nutrient sources (inputs) and resulting ecosystem services (outputs) from biological processing in lakes and streams. FPOM = Fine Particulate Organic Matter.

water habitats and the accelerated rates of extinction among key species. Time for research on the ecological and economic importance of species is short (Everard & Powell 2002; Dudgeon 2003), and there is growing concern about losing these services following declines in species diversity (Davies & Day 1998; Moulton 1999).

In this chapter we outline the types and importance of freshwater ecosystem services. In particular, we discuss the role of benthic species in ecosystem processes such as productivity, nutrient transformations, and decomposition of organic matter (Figure 3.1). We also examine patterns of inter-connected ecosystem processes and ways to evaluate them. We briefly review how particular sediment-dwelling organisms can alter freshwater ecosystem services. We discuss three major categories of ecosystem services: provisioning, supporting, and cultural (Millennium Ecosystem Assessment 2003). Each of these categories is then illustrated with examples of how benthic species provide different ecosystem services. The vulnerability of ecosystem services in fresh waters is dis cussed in Chapter 6, where we consider the concept of disservice (or the exploitation of one ecosystem service that leads to a negative effect or elimination of a second service) and review several case studies.

Berry Boosters

Berry Boosters

Acai, Maqui And Many Other Popular Berries That Will Change Your Life And Health. Berries have been demonstrated to be some of the healthiest foods on the planet. Each month or so it seems fresh research is being brought out and new berries are being exposed and analyzed for their health giving attributes.

Get My Free Ebook


Post a comment