Search

Faunistic and ecological studies on saproxylic Collembola species were carried out in the Wigry National Park (NE Poland). Nine sites representing Tilio-Carpinetum, Serratulo-Pinetum and Peucedano-Pinetum habitats each including three different levels of disturbance were visited twice in 2015. Samples from fallen logs in different stages of decay, neighboring litter and soil as well as arboreal epiphytes were taken on each visit. The Collembola specimens were then extracted using Tullgren funnels resulting in a total of 73 838 specimens from 270 samples. Specimen identification revealed the occurrence of 63 species, including 5 saproxylobiontic, 7 saproxylophilous, 4 xerophilous species living in epiphytic mosses and lichens as well as 47 hemiedaphic or euedaphic species. This composition of saproxylic fauna seems to be typical for the region with the most diverse assemblages being found in Tilio-Carpinetum habitats, while Serratulo-Pinetum and Peucedano-Pinetum are clearly less diverse. Additionally, a slight decrease in the number of Collembola species with increasing forest disturbance was observed. Furthermore, an increase in the number of Collembola species with the degree of dead wood decomposition was also found. This indicates that saproxylic springtail assemblages are sensitive to anthropogenic changes.

Homing rates and initial orientations after release from different directions were investigated in the solitary bee Dasypoda altercator. Homing rates and the proportion of individuals returning on the day of release declined with distance, implying that homing from greater distances is not based solely on the use of landmarks. A long duration of return (often not on the same day) and high efficiency of homing (four bees out of 10 returned from a 4 km distance over the lake), as well as an increase in average return speed ≅ 10 m/min) with distance of bees homing on the same day suggest that homing is also not based upon radial scatter as the sole tactic. This is supported by the observation that the initial orientations of the bees were not equally probable. Departures towards the sun greatly exceeded those away from the sun and the bees also tended to depart in cardinal geographical (or geomagnetic) directions, preferring meridional directions (especially southward) to parallel ones (of which east was preferred). Departure directions did not depend on wind direction but did depend, to some extent, on the landscape features of release sites. However, bees neither tended to depart in the direction of the nest, nor did homing success correlate with the direction of departure in relation to that of the nest.

This is the first study of the morphological and molecular variation in two peripheral populations of the butterfly Jutta Arctic, Oeneis jutta, a glacial relict species endangered by the fragmentation of its habitat in Poland. An analysis of the morphological characteristics indicates that both Polish populations are similar but differ significantly in some characteristics. Levels of genetic variation were assessed using mitochondrial cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 5 (ND5) gene fragments together with a segment of the mtDNA control region (CR) and a nuclear elongation factor-1a (EF-1a) gene sequence. In addition, the pattern of molecular variation in specimens from eastern and northern Europe was examined. Interestingly, the analysis of variation in a 932-bp sequence of the nuclear EF-1a gene in representatives of the populations studied revealed a relatively higher level of diversity than that of mitochondrial genes. There was evidence of divergence between the peripheral populations and lack of gene flow between them. The two closely situated populations had a high FST value (0.69), which clearly indicates their isolation. These populations appear to be demographically independent breeding units, with distinctive allele frequencies and consequently should be recognized as separate units for management and conservation. The preliminary results are in accord with an a priori subdivision based on collection areas and suggest that habitat fragmentation has affected the genetic diversity and structure of these populations.