University of Tasmania
whole_TanusilpVongwiwat2002_thesis.pdf (26.88 MB)

Factors affecting the aquatic macroinvertebrate (EPT) fauna at Nam Nao National Park, Thailand

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posted on 2023-05-27, 12:57 authored by Tanusilp, V
Little is known about the invertebrate communities, which inhabit the freshwater streams of northeastern Thailand. This study has investigated the macroinvertebrate assemblages, which live in several forest streams in the popular Nam Nao National Park located in the headwaters of several important northeastern rivers. The distribution and relative abundance of EPT taxa (orders Ephemeroptera, Plecoptera and Trichoptera) was investigated in relation to this environmental variability. The main purpose was to document the natural variation in these communities as a baseline against which to recognize detrimental impacts which may arise from increasing visitor pressure on the National Park. This was approached via three research questions: Do taxa occupy certain substrates preferentially at different times of the year? Does taxa richness differ in various parts of the streams (pools, riffles and runs)? and what is the nature of the small scale variation in close proximity to a pre-existing tourist facility? The streams, located in a monsoonal climate, were found to be highly variable in terms of monthly flows, substrates and other physico-environmental factors. The invertebrate fauna was sampled by Surber sampling, and was found to be very rich. It was dominated by mayflies and caddisflies, but had a low diversity of stoneflies. Responses to environmental factors differed at order, family and genus level. Some taxa were relatively insensitive to natural changes, others were sensitive at some times and at some sites, whereas others displayed clear preferences for certain habitat factors all year. Communities were recognized by TWINSPAN analysis and ordination methods. The project was successful in recognizing certain taxa, which were indicators for various environments at certain times of the year. A useful baseline dataset has been achieved which can be used in future as a benchmark for pristine water conditions in the National Park.


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Copyright 2002 the author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s). Thesis (MEnvSt) - University of Tasmania, 2002. Includes bibliographical references

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