In this master's thesis, we researched the influence of water level and human intervention
in the channel of the Stržen river on the structure of the macroinvertebrate community.
Since Stržen was regulated in the past and renaturation projects were conducted on it a
few years ago, we evaluated the ecological state of the ecosystem after the interventions.
Sampling took place in two renatured and two natural (reference) sections of the
watercourse, where we measured physical, chemical and hydromorphological
parameters, determined the percentage of macrophyte species coverage and collected
macroinvertebrate samples. When analysing the data, we calculated the abundance of
macroinvertebrates and various diversity and biotic indices, based on which we
determined the structure and diversity of macroinvertebrate community. We found 10,994
macroinvertebrate individuals, which we classified into 27 different families, of which
the Chironomidae family was the most represented. Changes in water level affected
certain abiotic factors, the abundance and diversity of macroinvertebrates. Compared to
the results from 2021, the improvement of conditions in the renatured small bend (sample
site M) is particularly evident, because the diversity of macroinvertebrates has increased.
Human interventions in the watercourse have negatively affected the ecological
conditions of the Stržen river, but since the restoration of aquatic systems is a long-term
process, we expect that the complexity of the macroinvertebrate community will increase
in the following years.
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