Beetles (Coleoptera) of the Bečva river and its surroundings at the site of the planned construction of the Skalička dam, part II.

Abstract

The Bečva River is the last of the major gravel‑bed rivers in the Czech Republic whose flow regime is not influenced by a dam on its main course. Although most of its channel was regulated during the 20th century, several short near‑natural stretches with valuable biota have been preserved. Moreover, following the floods at the turn of the 20th and 21st centuries, additional sections of the river have escaped the effects of earlier channelization, and a gradual restoration of natural river dynamics has been taking place. One such site is located near the village of Skalička. Coincidentally, this very place had been selected for the construction of a dam intended to provide flood protection and contribute to water retention in the landscape. However, the implementation of this project would undoubtedly have resulted in the destruction of extremely valuable habitats. For this reason, a group of entomologists initiated a comprehensive faunistic survey, which confirmed the presence of numerous species listed in the Red List of Invertebrates of the Czech Republic. The results of this research became one of the arguments that led to a reassessment of the original plan. It was decided that, instead of a dam, a dry side‑polder should be built here, a measure that – if carried out appropriately – would have a considerably smaller negative impact on the local nature. The present study builds upon the published results of the first phase of the survey and substantially expands our knowledge of the unique beetle communities occurring at the site. An additional 443 species were newly recorded; in total (including species reported in the previous publication), 834 species belonging to 74 families are now documented from the study area. Of these, 136 species are classified in one of the threat categories of the Czech Red List of Invertebrates. Species richness, including threatened species, is therefore higher at Skalička than in other protected riverine areas in the wider region. This can be illustrated, for example, by the genus Bembidion, of which 32 species have so far been found at Skalička–making it the richest locality for this genus within the Czech Republic. Among the most faunistically and conservation‑wise significant newly recorded species are: Agrilus guerini, Anogcodes rufiventris, Anthicus sellatus, Aphthona abdominalis, Bembidion striatum, Brachygluta xanthoptera, Cryptocephalus octopunctatus, Hydraena reyi, Hydrosmecta delicatula, Laccobius simulatrix, Mordellaria aurofasciata, Olibrus vako, Opatrum riparium, Pelecotoma fennica, Pelochares versicolor, Pentaria badia, Psammodius asper, Smaragdina flavicollis, Thinodromus hirticollis and Zorochros flavipes. The species Pentaria badia (Scraptiidae) is reported as new to the Czech Republic. The exceptional natural value of the locality is further underscored by the recent discovery of a species previously unknown to science (Olibrus vako, family Phalacridae), whose occurrence at the type locality Skalička has been confirmed by an additional record presented in this paper. In the final part of this study, recommendations are  proposed for the construction of the polder, the acceptance of which would substantially reduce the damage to local ecosystems. Nevertheless, the best solution would be to abandon the Skalička water‑management project altogether and seek alternative, far more nature‑friendly measures that would ensure not only flood protection but also contribute to water retention in the landscape and the preservation of the area’s extraordinary biological value. The surveyed area is of such significance that it should be designated as a specially protected area under Czech legislation.

Keywords

Czech Republic, dead wood, endangered species, faunistics, floodplain forest, gravel bars, habitat conservation, Moravia region, phytophagous beetles, polder, riparian beetles, saproxylic beetles, water beetles

Fulltext

Brouci (Coleoptera) řeky Bečvy a jejího okolí v místě plánované výstavby vodního díla Skalička, II. část