Ptyctimous mites (Acari: Acariformes: Oribatida) as zooindicators of changes in Dorrigo National Park in Australia (North Coast Bioregion)

The authors of the study present an analysis of the structure and changes in the examined community of ptyctimous mites (Acari: Acariformes: Oribatida) found in Dorrigo National Park in Australia. The research was conducted during two periods: between 1990 and 1993 and later in 2007. The analysed mite community comprises 35 species, though, the dominance and frequency of particular species were different for each period. In the first research period (1990–1993) in the area of Dorrigo National Park, 28 species were recorded, whereas in 2007 – 23 species were found. There were 16 species that occurred in both research periods, and 12 species only in the samples collected in the 90's, and 7 species only in those collected in 2007. The analysis also embraces the geographical distribution of the species in the area of Australia. Three species were designated as endemic, occurring only in the area of the examined national park (Austrophthiracarus dissonus Niedbala et Collof, 1997, Austrophthiracarus parapulchellus Niedbala, 2006 and Notophthiracarus distinctus Niedbala, 1989). The analysed samples contained only few specimens of these species. Due to the low abundance, great rarity of the local populations and high endemism, these species should be regarded as potentially endangered (EN according to the IUCN scale). A comparative analysis of the community from Dorrigo National Park (New South Wales) with those found in other larger areas of Australia in Victoria (Otway Ranges Area, Yarra Ranges Area, Strzelecki Ranges Area and Errinundra Plateau Area) examined by Niedbala and Szywilewska-Szczykutowicz (2017) has revealed that the communities found in Dorrigo National Park contained far more species, which constituted 30% of the whole fauna of Australia. In contrast to the communities of ptyctimous mites from Dorrigo, the individual communities in the area of Victoria contained only between 5% and 14% of all known species in Australia from this group.