Environmental factors influencing the occurrence of freshwater snails in woodland water bodies

Abstract

Studies were carried out in eight woodland water bodies that are situated in an urbanised area of Southern Poland (Upper Silesia). The aim of this study was to determine the influence of auto-and allochthonous plant detritus and exposure to sunlight on the structure of snail communities in woodland ponds. Among some physico-chemical water parameters, pH influenced the occurrence of snails, whereas sunlight caused an increase in diversity of the snail communities. In the total snail collection, 72.1% of specimens were gathered in sun-exposed sites. By the same degree of insolation more preferred by snails were the sites with allochthonic detritus. The snail fauna of subsidence ponds located inside a forest area differs from those occurring in urban agglomerations. The most conspicuous difference is the high numbers in three woodland ponds of Hippeutis complanatus (L.), which is rare in this area.

Occurrence and morphological variability of Gyraulus crista (Gastropoda: Pulmonata: Planorbidae) on different types of substratum in woodland ponds

“…For this reason, woodland ponds create specific habitats for the occurrence of invertebrates including freshwater snails. This was also confirmed in previous studies (Spyra 2010(Spyra , 2011. In this research, we found G. crista in only six ponds.…”

“…Previous studies that were carried out in woodland ponds (Spyra 2010) demonstrated that exposition to sunlight had no impact on the occurrenceof G. crista, and that individuals of this species were much more numerous in the autochthonous plant matter (Typha debris) as compared to allochthonous. Phragmites litter is nutritionally poor and an unfavorable food source for invertebrate detritivores (Kulesza et al 2008).…”

“…leaves and the remains of aquatic plants covering bottom sediments. It is also found in leaf detritus (Spyra 2010), on muddy sediments and stones (Hubendick 1947;Piechocki 1979) as well as on anthropogenic rubbish (Jatulewicz 2007).…”

The first record and occurrence of Stagnicola turricula (Held, 1836) (Gastropoda: Pulmonata: Lymnaeidae) in Upper Silesia (Southern Poland) in relation to different environmental factors

“…Thus, in this survey, the correlation of the occurrence of P. subtruncatum and the organic matter content in bottom sediments may also be explained by alimentation preferences. According to Spyra (2010), freshwater snails preferred sites that mainly had allochthonic detritus in anthropogenic reservoirs (Southern Poland, Upper Silesia): Radix balthica was more frequent on allochthonic detritus (F = 87.5%),…”

Aplexa hypnorum(Gastropoda: Physidae) exerts competition on two lymnaeid species in periodically dried ditches

“…hypnorum is known for its distribution in most European countries (Welter-Schultes, 2012, 2013 and North America (Dillon et al, 2006). But in some countries, the numbers of these snails were small such as in woodland ponds from Southern Poland (Spyra, 2010) and a few ponds of the upper Rhine valley (Mosimann, 2000;Bauer and Ringeis, 2002). This physid colonizes small and temporary waterbodies rich in vegetation, located in lowlands.…”