Integrating limnological characteristics of high mountain lakes into the landscape of a natural area |
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Authors: | Gary L Larson Andy Wones C David McIntire Barbara Samora |
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Institution: | (1) National Biological Survey Cooperative Park Studies Unit College of Forestry, Oregon State University, 97331 Corvallis, Oregon, USA;(2) Department of Botany and Plant Pathology, Oregon State University, 97331 Corvallis, Oregon, USA;(3) Mount Rainier National Park, Tahoma Woods, Star Route, 98304 Ashford, Washington, USA |
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Abstract: | A general conceptual watershed-lake model of the complex interactions among climatic conditions, watershed location and characteristics,
lake morphology, and fish predation was used to evaluate limnological characteristics of high mountain lakes. Our main hypothesis
was that decreasing elevation in mountainous terrain corresponds to an increase in diversity of watershed size and lake area,
depth, temperature, nutrient concentrations, and productivity. A second hypothesis was that watershed location and aspect
relative to climatic gradients within mountainous terrain influences the limnological characteristics of the lakes. We evaluated
these hypotheses by examining watershed location, aspect and size; lake morphology; water quality; and phytoplankton and zooplankton
community characteristics among high mountain forest and subalpine lakes in Mount Rainier National Park.
Although many of the comparisons between all forest and subalpine lakes were statistically insignificant, the results revealed
trends that were consistent with our hypotheses. The forest lake group included more lakes with larger watersheds, larger
surface areas, greater depths, higher concentrations of nutrients, and higher algal biovolumes than did the group of subalpine
lakes. Deep lakes, which were mostly of the forest lake type, exhibited thermal stratification and relatively high values
of some of the water-quality variables near the lake bottoms. However, the highest near-surface water temperatures and phytoplankton
densities and the taxonomic structures of the phytoplankton and zooplankton assemblages were more closely related to geographical
location, which corresponded to a west-east climate gradient in the park, than to lake type. Some crustacean and rotifer taxa,
however, were limited in distribution by lake type.
Fish predation did not appear to play an important role in the structure of the crustacean zooplankton communities at the
genus level with the exception of Mowich Lake, where crustacean taxa were absent from the zooplankton community. This was
the only lake inhabited by a true zooplanktivourous species of fish. |
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Keywords: | Limnology High mountain lakes |
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