Alderfly assemblages (Megaloptera, Sialidae) along an oligotrophic karst hydrosystem: spatial patterns and species-environment relationship

Abstract

Even though alderflies, as well as many other aquatic macroinvertebrates, are widely used as indicators of freshwater quality, the knowledge of their distribution, biology and ecology in karst freshwater habitats is still very scarce. Aiming to fill this gap, we investigated alderfly assemblages along an oligotrophic karst hydrosystem. Sampling was carried out on a monthly basis over a one-year period (2007/2008) in different types of freshwater habitats and microhabitats. Our goals were to determine population aspects, habitat and microhabitat preferences of alderflies as well as their relation to environmental factors. Due to the specificity of karst freshwater habitats, alderflies were rather rare in the studied hydrosystem. Yet, their fauna was diverse with four identified species, where Sialis fuliginosa Pictet, 1836 was the most widespread one. Sialis sordida (Klingstedt, 1932) was recorded for the first time in the Balkan Peninsula being the rarest species in our study. Substrate type and water velocity showed as key environmental parameters in determining alderfly assemblages. Alderflies were mostly recorded from a canyon type mountainous stream, and silt with leaf litter, respectively. They were not recorded at sites characterized by predominately solid stones (i.e. cobbles) and mosses, and with intermittent water flow. Our results strongly indicate that alderflies could be used in future conservation and protection management procedures in karst freshwater habitats.

One new species of Aneumastus D.G. Mann et Stickle (Bacillariophyceae) from Krka River, Croatia

“…The chemistry of groundwater is influenced by lithology, with varying degrees of karst formation and complex groundwater pathways (Cukrov et al 2007). The Krka River is characterized by tufa formations -an unusual phenomenon: secondary calcium carbonate deposits, which are the result of calcium carbonate precipitation and biotic activity (Primc-Habdija & Matoničkin 2005;Vilenica et al 2018). A lentic dilatation of the Krka River is Lake Visovac, which also belongs to a group of karstic barrage lakes (Gligora Udovič et al 2017).…”

Long-Term Chironomid Emergence at a Karst Tufa Barrier in Plitvice Lakes National Park, Croatia

“…Plitvice Lakes was chosen as a study site because the anthropogenic impact on the system is minimal [17]. Ongoing research on insect emergence in Plitvice Lakes has already provided some valuable information on the phenology and ecology of various aquatic insects: namely, Trichoptera [18], Ephemeroptera [19,20], Plecoptera [21], Odonata [22], Megaloptera [23], Neuroptera [24] and various Diptera families [16,[25][26][27][28][29][30][31][32].…”