Many thanks for your thoughtful answer to my question about aquatic
biodiversity, management and mapping.
Based on what you've told me, and my (entirely hypothetical ;-)) need to put
some type of management in place in only a short time with only a small
budget (limiting my biological survey work to a team of one grad student
with a summer student) and not much say about who calls the shots on the
watershed (whether local communities, a pulp and paper company, or the
Minister of Natural Resources), here's what I'd do:
1. Knowing my broad macroclimatic subdivisions, plus the buffering capacity
of soils and rocks in my area and the predominance of coniferous, mixed, and
deciduous forest stands on a watershed basis, I'd attempt a classification
that would separate blackwater oligotrophic, clearwater mesotrophic, and
turbid water eutrophic types in the relatively pristine (well, too bad about
acid rain :-(( ) upper reaches of my watershed (upstream from agro-urban
influences). Downstream, I'd have to approach things differently.
2. I'd use my 1:10,000 scale aerial photos or fine-scale GIS topographic
layer with other gis tricks and tools to map out sections of stream
to map sections of stream according to (a) predicted flow based on
catchment area and channel width, and (b) the slope of the land under the
stream (or lake) and its width. My guess is that these variables are
related to water depth and flow rate, both of which would affect the nature
of the substrate (gravelly, sandy, or rich in organic matter) water clarity
and light penetration (apologies for inappropriate or imprecise terminology).
3. On sites pulled from the strata identified in step 2, I'd send my
student crew to characterize the physical attributes of the stream,
including flow rate, depth, character of the substrate, etc., and to do an
inventory of aquatic plants, both submerged and emergent, vertebrates, and
invertebrates.
4. The grad student would do some fairly standard ordination/classification
work, linking the biotic community with the physical attributes of the
stream and substrate, and evaluating our ability to map these with available
tools. In a short period of time you'd have a shaky but consistently shaky
inventory of stream sections, lakes and ponds classified using important,
community-correlated biophysical factors.
5. I'd establish permanent sampling plots representative of these strata to
monitor changes.
What have I left out, besides a deserving group of highly-trained
entomologists, biologists, hydrologists, and botanists! :-(
> The best predictors of aquatic community structure are suites of
>organisms that represent fundamental phase states for any given habitat.
>In plain English, this means that it is important to know if, say, ponds
>have high transparency and well-developed submerged macrophyte communities,
>or if they are subject to massive phytyoplankton blooms and have relatively
>sparsely vegetated littoral zones, or else heavy growths of water lillies,
>the other two littoral phases you'd be likely to encounter.
Are these pollution-dependent, or somehow naturally cyclical phenomena?
> When the community makes its decisions about the future, it has to
>be kept in mind that maintenance of intact ecosystems and maximization of
>game are overlapping objectives, potentially, but the area of overlap is
>not huge. It is necessary to consider other values, such as scenic,
>recreational, and ethical. That last one is always difficult to bring to
>the table, but it is probably the most important one of all.
>
Is beauty an inherent quality of something, or is it merely in the eye of
the beholder? Maybe we'll leave this one for another list to deal with!!
Please send more
Vince Zelazny