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Although large branchiopods are undoubtedly an important part of the temporary water bodies, they remain the least studied group of macroinvertebrates inhabiting freshwaters. One of these species is the fairy shrimp Branchipus schaefferi. Its known occurrences across the central Europe are limited almost exclusively to temporary pools on military training grounds. Thus, the species is particularly threatened by changes in military activities, especially by the decline in the number of temporary pools caused by abandoning of training grounds followed by the secondary plant succession. In the present study, we performed genetic analyses of known populations of B. schaefferi in military training grounds of Poland using nuclear 18S ribosomal DNA sequences. No genetic diversity was observed among nine populations from four military grounds. Further, very close phylogeographical relationships among B. schaefferi from distant geographic areas (Poland, Italy and Algeria) were found (genetic distance of 0.001-0.002 substitutions per site). [ABSTRACT FROM AUTHOR]

Water availability is one of the most important factors for terrestrial life. Terrestrial habitats may periodically become dry, which can be overcome by an organism's capability to undergo anhydrobiosis. In animals, this phenomenon has been reported for invertebrates, with tardigrades being the best-known. However, different tardigrade species appear to significantly differ in their anhydrobiotic abilities. While several studies have addressed this issue, established experimental protocols for tardigrade dehydration differ both within and among species, leading to ambiguous results. Therefore, we apply unified conditions to estimate intra-and interspecies differences in anhydrobiosis ability reflected by the return to active life. We analysed Milnesium inceptum and Ramazzottius subanomalus representing predatory and herbivorous species, respectively, and often co-occur in the same habitat. The results indicated that the carnivorous Mil. inceptum displays better anhydrobiosis survivability than the herbivorous Ram. subanomalus . This tendency to some degree coincides with the time of "waking up" since Mil. inceptum showed first movements and full activity of any first individual later than Ram. subanomalus . The movements of all individuals were however observed to be faster for Mil. inceptum . Differences between the experimental groups varying in anhydrobiosis length were also observed: the longer tun state duration, the more time was necessary to return to activity.