Spiders and pseudoscorpions on old pedunculate oaks (Quercus robur) with tree cavities were studied in a Central European floodplain (South Moravia, Czech Republic). Altogether 322 specimens from 47 spider taxa and 71 specimens of six pseudoscorpion species were collected during 2010 and 2011 from tree cavities using two methods. More specimens and species of spiders were obtained from flight interception traps and more specimens and species of pseudoscorpions were obtained from pitfall traps. Remarkable records represent typical cavity dwellers, i.e. the spider Midia midas (Simon, 1884), the pseudoscorpions Larca lata (Hansen, 1884) and Apocheiridium ferum (Simon, 1879), the latter occurs mostly under tree bark. Five arachnid species are listed in the Czech red list: Midia midas, Leptorchestes berolinensis (C. L. Koch, 1846), Dipoena erythropus (Simon, 1881), Larca lata and Dendrochernes cyrneus (L. Koch, 1873). Zusammenfassung. Spinnen und Pseudoskorpione alter Stieleichen (Quercus robur) mit Baumhöhlen wurden in einer mitteleuropäischen Aue (Südmähren, Tschechische Republik) untersucht. Insgesamt wurden 322 Individuen aus 47 Spinnentaxa und 71 Individuen aus sechs Pseudoskorpionarten in den Jahren 2010 und 2011 mit zwei Methoden erfasst. Spinnen wurden in höhere Individuen- und Artenzahl mit Kreuzfensterfallen und Pseudoskorpione zahl- und artenreicher in Bodenfallen in Baumhöhlen gefangen. Bemerkenswerte Artnachweise betreffen typischer Baumhöhlenbewohner: die Spinne Midia midas (Simon, 1884) sowie die Pseudoskorpione Larca lata (Hansen, 1884) und Apocheiridium ferum (Simon, 1879), letztere kommt vor allem unter Baumrinde vor. Fünf Arten sind in der Tschechischen Roten Liste enthalten: Midia midas, Leptorchestes berolinensis (C. L. Koch, 1846), Dipoena erythropus (Simon, 1881), Larca lata und Dendrochernes cyrneus (L. Koch, 1873).

First records of pseudoscorpions from Lithuania are presented based on specimens preserved in Lithuanian collections and new material collected during the latest ten years. Pseudoscorpions were collected at 25 localities in both deciduous and coniferous forests at altitudes of 5 to 186 m above the sea level. Sifting of litter and moss, pitfall traps and collecting by picking under the bark of deadwood were used as the collecting methods. Altogether 132 specimens belonging to eight species from three families were recorded. The findings of Neobisium crassifemoratum (Beier, 1928) represent the northernmost known records of the species.

Fragments of woodland represent important natural and semi-natural elements that contribute to ecological stability and biodiversity in a landscape. In the Czech Republic, they are part of the Territorial System of Ecological Stability (TSES), which consists of bio-centers, bio-corridors, and interaction elements. The presence of fragments of woodland is of growing importance in the agricultural landscape, where they provide effective protection against soil erosion and serve as a refuge for many animals, whose presence is crucial in maintaining essential ecosystem functions. A functioning ecosystem is especially important in intensively farmed landscapes, which are exposed to frequent and heavy disturbance. Our aim was to evaluate the influence of certain habitat characteristics of fragments of woodland on the activity-density and species richness of selected groups of soil invertebrates (ground beetles, spiders, harvestmen, centipedes, millipedes, and isopods). The research was conducted in the agricultural landscape of South Moravia (Czech Republic) in the summers of 2016–2017, for which we used pitfall traps to collect soil invertebrates on preselected fragments of woodland. The results highlight a wide range of habitat preferences of individual groups of invertebrates, wherein it is not possible to clearly determine the most favorable environmental conditions for all organisms. Consequently, the priority should be to maintain the highest possible degree of heterogeneity among natural and semi-natural features, including with respect to their surrounding landscape. In addition, we found that due to their small size and width, fragments of woodland that are not included in the concept of bio-centers and bio-corridors can similarly support the activity-density and diversity of soil fauna.

(1) Nesting of the great cormorants strongly influences terrestrial ecosystems by physical destruction of vegetation and chemical changes in the soil and around the nesting colonies. (2) We investigated spider, harvestmen, and centipede assemblages in different influenced plots (starting colony, active dense colony, and partly abandoned colony) in the biggest Lithuanian cormorant colony in pine woods on the shore of the Baltic Sea in the Curonian Spit National Park in Lithuania. Selected groups of ground dwelling predatory arthropods were collected by pitfall traps in 2012–2014. (3) We recorded a total of 4299 spider specimens (102 species), 451 harvestmen specimens (9 species), and 1537 centipede specimens (7 species). The coverage of moss and herb vegetation, mean Ellenberg value for light, bare ground without vegetation, and number of nests significantly influenced the abundance, species richness, and ecological groups of arthropod predators. (4) Active ground hunters represented by spider Trochosa terricola and centipede Lithobius forficatus were positively influenced by bare ground without vegetation and a higher density of nests, and negatively influenced by an increasing coverage of moss and herbs. The opposite effect was found for web builder spiders and less movable species, represented by dominant spider species Diplostyla concolor and harvestmen Nemastoma lugubre and Oligolophus tridens. (5) The results show how cormorant influence the forest vegetation structure and affect the abundance and species diversity of ground dwelling predatory arthropods.

Spiders are common inhabitants of tree hollows, as well as bird nesting boxes, especially in autumn and winter. Some species of spiders use bird nesting boxes for overwintering. We investigated spider assemblages in nesting boxes and how temperature influences the abundance of overwintering spiders in nesting boxes in lowland forest in the Czech Republic. The study was conducted in the European winters of 2015–2017. In total, 3511 spider specimens belonging to 16 identified species were collected from nesting boxes over three years in late autumn and winter. Almost all species were arboreal specialists. The dominant species were Clubiona pallidula, Anyphaena accentuata, Platnickina tincta, and Steatoda bipunctata. Although the tree species had no effect on the abundance of overwintering spiders, the presence of nest material affected the abundance of spiders in the nesting boxes (preferred by C. pallidula and P. tincta). In general, spiders resettled nesting boxes during winter only sporadically, however A. accentuata reoccupied boxes continuously, and its activity was positively correlated with the outside temperature. Nesting boxes support insect-eaters all year around—birds during spring and summer and spiders during autumn and winter.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic