05/31/2000 Env Bd Packet - Laserfiche WebLink

Home Search

Defining Restoration Goals Table 1. Advantages and disadvantages of designing restoration with respect to different types of goals. Level Advantages Disadvantages & Causes of Failure Species Rescue of endangered species Lack of recognition of ecosystem- and landscape - Increase in biodiversity level interactions and processes Inadvertent damage to other species Attention to one target species may divert attention to other species Ecosystem functions Recognition of large -scale processes Definition of "ecosystem" unclear; can lead to problems identifying unit to be restored necessary for species' persistence p Encouragement of integration of management Definition of "ecosystem function" unclear; goals of diverse agencies, interest groups functions are heterogeneous in scale and generality, Recognition of dynamic nature of ecological and are poorly correlated with each other entities Ecosystem services Generation of public support, funding Same problems of definition, scale as with ecosystem Specific actions readily identified function Value depends on constancy of "willingness -to -pay," economic conditions Creation of one service may preclude others larger -scale processes may lead to failure of reintroduc- tions, many of which may appear paradoxical (Mon- talvo et al. 1997). An excellent example of such prob- lems is the attempt to create habitat for the endangered Light- footed clapper rail in salt marshes of southern California (Zedler 1996). Although the correct vegeta- tion and hydrology were restored at the mitigation site, nitrogen cycling was limited by sediment texture, re- sulting in stands of Spartina foliosa (saltmarsh grass) that were too short and sparse to allow birds to breed. Ef- forts to increase nitrogen supply by fertilization only re- sulted in allowing another plant, Salicornia bigelovii, to competitively displace the desired grasses (Boyer & Zedler 1999). Because of the linkage of sediment texture at the created site to nitrogen dynamics, and their link- age to the composition of the vegetation, all attempts to restore the rail at this site have been abandoned (J. Zedler, personal communication). It is likely that simi- lar unforeseen connections between habitat variables and ecosystem or landscape processes have affected other species -based restoration efforts. Another problem, sometimes associated with species - based restoration, is the ancillary damage done to other species as a result of an intense effort focused on one spe- cies. Meffe (1992), for example, described attempts to re- store salmonid fisheries in the Pacific Northwest as "techno- arrogance" because the methods used to increase fish populations are causing a variety of other conserva- tion problems, such as increased fishing of native salmon stocks and genetic pollution of native populations. He points out that similar problems have arisen with efforts to restore other endangered species, including sea turtles. Species- oriented restoration implicitly demands that the restoration effort attempt to recreate the habitat of the target species, without regard to the habitat require- ments of co- occurring species, including species over the complete spectrum of organisms — microbial, floral, and faunal —that make up an ecosystem. The widely ac- cepted view of communities as individualistic associa- tions of species suggests that the community that devel- ops in a site restored to meet a particular species' needs may or may not be similar to communities in which the target species was originally found. Thus, the agency or group that decides which species should be the object of restoration efforts may inadvertently cause the loss of habitat for species for which there are no competing in- terest groups to generate public support. It follows that if conservation and restoration are focused exclusively on species, as called for by Goldstein (1999), for exam- ple, non - target species, especially small, obscure species in poorly known groups, may inadvertently suffer. Ecosystem Functions and Ecosystem Management Perceptions of some of the problems associated with spe- cies-based conservation, together with a widespread in- crease in appreciation for the integrated function of whole landscapes, led to the development of ecosystem based paradigms for directing conservation and restoration ef- forts (Risser 1995; Walker 1992, 1995), and of ecosystem management as an approach to land management and res- toration (Grumbine 1994; Christensen et al. 1996; Pearson & Klimas 1996). This approach recognizes that the viability of populations of all species, including rare and endan- gered species, depends on the maintenance of large -scale as well as small- scale, ecological processes, on the presena of a characteristic mosaic of community types over a broac area, and on the movements of individuals and popula lions over large areas. The advantages of using ecosystem management a: an organizational framework for restoration have bees well summarized by Allen (1996) (Table 1). He point 4 Restoration Ecology MARCH 20(