Public science data suggest that fish is the most important factor in reducing small pond biodiversity in Czechia

This project tested a public-science approach to the assessment of freshwater habitat quality via simple invertebrate sampling. We combined a mobile phone application and simple instruction to children to sample 50 ponds in Central Czechia, and we analyzed the data using a standard ecological statistics approach. Despite the limitation in scope and taxonomic precision, our data revealed the same patterns as academic studies of the same topic. Specifically, we conclude that the main cause of invertebrate community decline is fish overstocking, while diverse invertebrate communities require aquatic macrophytes. Pollution detectable by children has an effect on invertebrate community structure, but a different effect than fish has, and not as statistically robust. Importantly, almost all large ponds were found overstocked with fish; therefore they support not more diversity than small ponds, but less, and serve as ecological traps. Our findings suggest that pond conservation should focus primarily on the restoration of aquatic vegetation, and that the most effective approach will be the removal of excessive fish.

Comparative Investigation of Aquatic Invertebrates in Springs in Münsterland Area (Western Germany)

The main aim of this study was to investigate the abundance of invertebrates in groundwater in relation to groundwater conditions (groundwater table, discharge, rainfall, and physio-chemical parameters), and to examine the suitable time for invertebrate sampling in springs. Thus, eight springs in two separate study areas, “Baumberge” and “Schöppinger Berg” (Münsterland area, North-Rhine Westphalia in Germany), were sampled five times (24 h for 2–5 consecutive sampling days) between November 2018 and October 2019. The results showed high spatial and temporal variance. In general, the existence of invertebrates and stygobites increased, whereas invertebrate types decreased with increasing hydraulic head and spring discharge. Therefore, investigating the abundance of invertebrates and invertebrate species is recommended to be done separately. Abundance of invertebrates was affected by different factors in both areas. Spearman correlation test (two-tailed) and factor analyses (n = 80, p ≤ 0.01) highlighted the importance of detritus as the main controlling factor for invertebrate existence and stygobite individuals in Baumberge, whereas dissolved oxygen is essential for their existence in Schöppinger Berg.