Populační struktura blešivce potočního jako indikátor předchozího vyschnutí toku
| Title in English | Population structure of Gammarus fossarum as an indicator of preceding stream drying |
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| Authors | |
| Year of publication | 2019 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Global climate change has among other effects,impact also on stream drying. That affects aquatic invertebrates populations, as for example the populations of Gammarus fossarum. While in most permanent streams this species has high abundances, in intermittent streams are these populations strongly affected. Mostly because this species has no drought-resistant stage, and therefore has to recolonize the strem from nearby perennial parts of the stream, or from residual pools. We compared populations of this species from 12 pairs of intermittent and perennial localities from years 2012-16 and foung out, that recolonization changes the population structure of this species even after few weeks after stream rewetting. Beside significant decrease of abundances, there was also significant decrease of juvenile to adult ratio and increase in larger individuals and males in the population. (Bigger body - faster migration). We also carried out fecundity analysis in year 2017, comparing the situation in residual pools and nearby perennial reaches. In this experiment we discovered significant decrease of gravid females in the population. This phenomenon can relate to higher predation pressure in loaded residual pools, where stress increases and cannibalism can occur. These results indicate, that populations of Gammarus fossarum are strongly affected by drought and therefore Gammarus is one of possible indicators of previous drought in streams. |
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