Changing Microarthropod Communities in Front of a Receding Glacier in the High Arctic

Abstract

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.

Diversity and Distribution of Mites (Acari: Ixodida, Mesostigmata, Trombidiformes, Sarcoptiformes) in the Svalbard Archipelago

“…For example, at the Midtre Lovén glacier foreland, two oribatid species, Camisia foveolata and Tectocepheus velatus, were the first colonizers. Mesostigmata appeared later, Proctolaelaps parvanalis being the first species recorded at this glacier foreland [10]. All these species are widely distributed in different parts of the archipelago (see Table 1).…”

“…Studies conducted during the past 20 years have also added 16 species of Mesostigmata [8,18,20,27,28,30,85,92,93,95,98,166] and 36 species of Sarcoptiformes to the Svalbard fauna [8][9][10]67,71,72,74,146,167]. This indicates that despite the relatively long history of mite studies for a region in the Arctic, our knowledge remains surprisingly poor.…”

“…As a consequence of the increasing temperatures and changes in precipitation patterns, many glaciers are receding and revealing new land surfaces for primary succession. Therefore, regions such as Svalbard offer a unique opportunity to identify the pioneer species that first colonize barren post-glacial habitats and to analyze long-term processes of change, e.g., in invertebrate community assembly [10].…”

“…Changing climatic conditions that determine and stimulate changes in habitats also affect the ranges of some mite species. Several studies have considered changes in mite communities in Svalbard in space and time; their dispersal abilities [11][12][13][14][15][16][17], as well as their emergence in new areas or retreat from previously occupied locations [10,[18][19][20]. The uniqueness of polar areas, with their characteristic climates and isolated island distribution that often restricts dispersal processes, limits the range of some species.…”

The Use of Wood Chips for Revitalization of Degraded Forest Soil on Young Scots Pine Plantation

“…Previous studies have shown that the introduction of a 1-cm thick layer of forest litter into a suitable substrate, e.g., wood chips, is sufficient to inoculate soils with edaphon [25,33,35,36,[39][40][41]. On the one hand, these small animals have limited adaptability to new habitats [42][43][44], but on the other hand, some studies show that oribatid mites appear very early in adverse habitats, even on the glacier foreland [45] or on post-industrial dumps [46]. Haimi [38] believes that the presence of mesofauna, which restores the soil biological activity, is important during soil remediation operations.…”