Monday, November 9, 2009

Welsh and Ollivier (1998) responce

In the terms of stream conservation, Welsh and Ollivier (Ecological Applications: 8, 1118-1132) did a good job at showing distinctly how the influxes of sediment from road construction affected amphibian densities and populations, within the vicinity of human populations. By comparing amphibian population in streams impacted by sedimentation to neighboring, unimpacted streams, the authors provided results describing three common species’ responses as being species specific and varying by mesohabitat type. In doing so they provide evidence that careful monitoring of these populations in streams, especially in areas in the vicinity of human disturbance, may be a valuable indicator of ecosystem health. They displayed that amphibians could be good in monitoring stream ecosystems. However, this paper did very little to address an ecosystem service, as I see it's definition being the monitory value that the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life.

Ecosystem health surveys main aim is to establish how well the habitat can sustain populations of native organisms. These are not done for the direct benefit of humans. Indirectly, a well maintain ecosystem can benefit humans in many ways, including, among other things, better fishing habitats, aesthetic views, etc. I see no direct monetary value to humans in use of amphibians as indicators. Furthermore, I see that, in the terms of monitoring streams that other indicators has done a good job as indicators (specifically, Ephemeroptera, Plecoptera, and Tricoptera relative abundance and diversity); through theses taxa are, according to our authors "short-lived, explosive breeders, or subject to seasonal movements...which can complicated their use as bioindicators."

In all, every measure that that these papers make are indirectly for the benefit of humans, most of the time monetarily, in one way or another (i.e., aesthetic, water quality, etc.). This is just a new "hip" term that is used to catch the eye and interest of the reader.

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