A faunistic and ecological characterization of the water mites (Acari: Hydrachnidia) of the Bukowa River (central-eastern Poland)

Abstract

The water mite communities of the Bukowa River were found to be similar to those of other lowland rivers in Poland. An element specific to the Bukowa River was a much higher abundance of Lebertia inaequalis than in other Polish rivers. Another distinctive element was the very high numbers of Arrenurus crassicaudatus, but this taxon should be considered allochthonous – its presence in the river was due to the periodic inflow of water from fish ponds. The largest synecological group was rheophiles and rheobionts, which together accounted for 80% of the fauna. The very large quantitative share of rheobionts and rheophiles is indicative of the natural character of the river, and the physicochemical parameters confirm its good water quality. More individuals (1764) and species (47) were caught in the lentic zone of the river than in the lotic zone (1027 individuals, 32 species). The species most associated with the lotic zone and fast water flow were Sperchon clupeifer and Hygrobates calliger. Data from the Bukowa River, as well as other rivers of the Janów Forests Landscape Park, indicate that the most characteristic habitat for Lebertia inaequalis is the lentic zone, with abundant water vegetation. The typical habitats of Hygrobates setosus are marginal pools and zones with slower water flow. Mideopsis crassipes and Torrenticola amplexa were associated with the upper course of the river. Sperchon clupeifer was associated with lotic habitats of the middle and lower course of the river, and Hygrobates setosus and Forelia variegator were associated with habitats with slower flow in the middle and lower stretches of the river.

Keywords

• lentic zone
• lotic zone
• longitudinal profile of the river
• synecological groups
• species diversity