Despite a widespread recognition of the role of seabird colonies in the fertilization of nutrient-poor polar terrestrial ecosystems, qualitative and quantitative data documenting any consequential influence on soil invertebrate communities are still lacking. Therefore, we studied community structure and abundance of springtails (Collembola) in ornithogenic tundra near two large seabird colonies in Hornsund, south-west Spitsbergen. We found considerably (5–20×) higher densities and biomass of Collembola in the vicinities of both colonies (the effect extending up to ca. 50 m from the colony edge) than in comparable control areas of tundra not influenced by allochtonous nutrient input. The most common springtails observed in the seabird-influenced areas were Folsomia quadrioculata, Hypogastrura viatica and Megaphorura arctica. The latter species appeared the most resistant to ornithogenic nutrient input and was found commonly closest to the bird colonies. Collembolan abundance decreased with increasing distance from the seabird colonies. However, relationships between collembolan density and specific physicochemical soil parameters and vegetation characteristics were weak. The most important factors were the cover of the nitrophilous green alga Prasiola crispa, total plant biomass and soil solution conductivity, all of which were correlated with distance from the colony and estimated amount by guano deposition. Community composition and abundance of springtails showed no evidence of being influenced of seabird diet, with no differences apparent between communities found in ornithogenic tundra developing in the vicinity of planktivorous and piscivorous seabird colonies. The study provides confirmation of the influence of marine nutrient input by seabirds on soil microfaunal communities.

Although soil water repellency (SWR) has been reported under different soils, climates, and vegetation types of the world, especially in forest land and following wildfires, the understanding of this variable continues to be rather limited. This study presented the characterization of SWR from wild fire measurements in a Scots pine Peucedano-Pinetum forest in the Kampinos National Park (central Poland), which is characterized by a temperate continental climate. The main objectives were: [i] To evaluate the potential occurrence, intensity, and persistence of soil water repellency in the surface layers of podzolized rusty soils during a dry summer; [ii] to determine whether a wildfire increased SWR, compared to the unburnt condition of soil; and [iii] to identify changes in hydrophobicity 13 months after a fire. The Water Drop Penetration Time (WDPT) test was used to assess persistence and intensity of soil SWR. Hydrophobicity is a natural phenomenon during periods of drought in temperate continental climates. The extreme class of SWR was observed in surface layers of up to 20 cm. A higher hydrophobicity was noted in the older habitats of the Peucedano-Pinetum forest. Maximum WDPT values (10,800 s) were found for an older ecosystem cover, during a dry summer. SWR in fire-affected soils is dependent on the intensity of the fire, as well as displaying spatial and seasonal variability. Thirteen months after a fire, the highest variability in the occurrence of non-wettability, was recorded in the surface layers of areas affected by a weak fire. A positive relationship between soil pH and WDPT values was determined to a 20 cm depth. Prolonged dry periods resulting from global climate change, may enhance the effects of increasing SWR; it therefore seems reasonable for future research on biosphere–climate interactions, to take the presence of hydrophobicity into account.

This study was carried out at Ny-Ålesund on Spitsbergen in Svalbard (High Arctic). Eight study sites were established along a transect from the fjord to the snout of the glacier. The sites differed from each other by the type of vegetation cover and soil characteristics. Soil samples were collected and placed in Tullgren funnels. Extracted arthropods were represented by two groups of mites (Mesostigmata and Oribatida) and springtails (Collembola). The pioneer species that occurred first after retreat of the glacier were representatives of the Collembola (Agrenia bidenticulata and Hypogastrura concolor). Later, other springtails appeared including Folsomia alpha, Folsomia quadrioculata, Hypogastrura concolor, Isotoma anglicana, Sminthurinus concolor and the first species of oribatid mites; Camisia foveolata and Tectocepheus velatus velatus. Arthropod communities recorded along the transect were characterized by large variations in both species composition and abundance of individuals. The greater the distance from the glacier snout, the greater the species richness (2 to 22 species). The mean number of species per sample was the lowest at site 8 (1 ± 0.71) (the closest to the glacier) and greatest at site 1 (14 ± 1.41) (furthest from the glacier). The Simpson’s diversity index (D) was distinctly greater at sites 1 (4.61 ± 0.06) and 3 (3.94 ± 0.11) than at other sites, especially site 8 (1.07 ± 0.06). Densities were least in the samples closest to the glacier (30 to 101 individuals; density 3000–10,100 individuals/m2). At the other locations, abundance was highly variable (905 to 7432 individuals; density 90,500–743,200 individuals/m2). The mean abundances were greatest at sites 2 and 3. The great variations in total abundances observed were often due to the presence or absence of one or more dominant species exhibiting extreme abundance variability between sites. The microarthropod community of the High Arctic is composed of heterogeneous circumpolar species, yet on a landscape scale is extremely dependent on local environmental conditions which may be subject to rapid change.