Preliminary data on the distribution and phenology of Eubranchipus grubii (Dybowski 1860) (Crustacea: Anostraca) in the Wielkopolska region
The paper presents preliminary data on phenology and distribution of Eubranchipus grubii in the Wielkopolska region (W Poland) collected in 2008. In total, 211 water bodies were sampled during a field survey and E. grubii was recorded in 38 out of them (18%). On ten localities the species was recorded for the first time.
The occurrence of the species was recorded already at the beginning of February, in five of the seven ponds sampled in two-week intervals. This has been the earliest observation of E. grubii ever recorded in Poland. Individuals from two of the studied populations had already well formed sexual traits, indicating that hatching might have occurred already in December. The maximum occurrence period of the species recorded in studied populations was 12 weeks. Two of the sampled populations became extinct before reaching maturity, ca. 3 weeks after hatching.
Rafał Bernard, Radosław Jaros, Juliusz Samoląg and Jakub Z. Kosicki
Monitoring studies in Strzaliny, one of the greatest hibernacula in Poland, comprised 31 annual bat censuses (1989–2019). The abundance peaked in 2002 for Myotis myotis, 2009 for Myotis nattereri and 2008 for the whole assemblage. Comparison of the maximum abundance in the monitoring period with that from 1980 to 1982 showed an almost fourfold increase for the whole assemblage, tenfold increase for M. nattereri and fourfold increase for M. myotis.
In 1989–2019, the numbers of M. myotis, M. nattereri, Myotis daubentonii and Plecotus auritus were fluctuating, but most of the recorded changes could not be explained by methodological problems or a direct human impact. Therefore, the cumulative results largely reflected the real trends in the species abundance. A long-term upward trend in the whole bat assemblage was recognisable, but with a stable or slightly decreasing phase in the last decade. An upward trend in M. nattereri was even stronger and has only slightly flattened recently. In M. myotis, the trend was clearly upwards up to the early 2000s, but weakly downwards in the following years. In M. daubentonii and P. auritus, no significant trend was determined. In strongly fluctuating M. daubentonii, the numbers were mostly moderate or high, and even increasing, up to 2008 and only moderate or low in the following years. In P. auritus, an increase occurred in the 1980s and early 1990s, and then, after the stochastic human-induced drop in 1994, its abundance remained relatively stable.
The population trends in Strzaliny largely reflected the general trends assessed for a large part of Europe. This suggests that the general population trends may be recognisable even in one large winter assemblage if it is reliably and consistently monitored through a long period. In this context, the hibernaculum in Strzaliny appeared to be a model object for such studies.