Estimation of the populations status and habitat conditions of Anseriformes in the State Nature Reserve «Gydansky» (Russia) using ultralight aviation
Authors: Rozenfeld S.B., Kirtaev G.V., Rogova N.V., Soloviev M.Yu., Gorchakovsky A.A., Bizin M.S., Demianets S.S.
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The Gydan Peninsula is one of the least explored and inaccessible Arctic regions in both the Yamalo-Nenetsky Autonomous Okrug and Russia as a whole. In 2016–2017 we conducted a survey of the Gydansky State Nature Reserve and adjacent areas, counted and assessed the quality of habitats of Anseriformes and their threats. The results of the study and the data volume obtained have proved the effectiveness of using ultralight aviation to study a hard-to-reach and vast area. We elaborated the methodology of aerial surveys and counting, the technique of population abundance extrapolation based on modern statistical methods and the use of Landsat images. According to the data obtained, we created GIS databases on abundance, biotopic distribution, key conservation areas of Anseriformes and threats. On their basis, it will be possible to develop a scheme of long-term monitoring of Anseriformes, and specific recommendations on the protection regime. By preliminary assessing the habitat quality on the selected plots, we found that Anseriformes form main groupings on salt marshes, although their areas on the Gydansky Peninsula are not large. The preliminary study of the feeding spectrum of herbivory Anseriformes (Anser, Branta, Cygnus) showed that on three studied sites, a significant proportion of their diet is occupied by common plant species of salt marshes (Carex subspathacea + Puccinellia phryganodes). Studies of the pastures quality on salt marshes on molting sites and on control sites demonstrated that Anser albifrons and Branta bernicla provoked a decrease in phytomass of dead grass by an average of 5.3 times. This increases the pasture quality and prevents turfness. On the molting sites examined, the phytomass of the main feeding plants was on average 4.6 times less than on the control sites. However, we can not consider it as a negative influence, since the constant pasture grazing stimulates the vegetation growth. Based on data obtained during the preliminary study, we established the impact of Anseriformes on invertebrates. We found that on control sites, the number of spider species was two times higher than on molting sites, and their number was four times higher than on molting sites. There were no significant differences in the Acarini number. The presence of mass concentrations of Aneriformes influences the structure of dominance in the microarthropod communities. We did not establish the influence of the Anseriformes concentrations on the diversity and species composition of Coleoptera and Heteroptera. Although on sites of mass concentration of Anseriformes, the number of Heteroptera predators greatly reduced (in 3–23 times). We showed that Ursus maritimus have became an important factor that influence the Anseriformes abundance, especially colonial species. We distinguished the nine sites which are the most important for Anderiformes. Within these areas, annual monitoring of Anseriformes using ultralight aviation is most relevant. On the distinguished key sites outside the Gydansky State Nature Reserve, it would be advisable to create regional-level complex sanctuaries with complete hunting ban. The presence of people and transport in protected areas will create an increase in the disturbance factor and poaching. It is necessary to strengthen the protection regime and conduct raids to combat poaching both in the Gydansky State Nature Reserve and on distinguished key sites. We propose the use of ultralight aviation as the most effective method for these targets. The results of obtained aerial surveys showed that the highest abundance of Polysticta stelleri, Somateria spectabilis and Clangula huemalis, the maximal concentrations of molting Cygnus bewickii, Anser albifrons, A. fabalis and Branta bernicla were recorded on Neupokoev Island and Vilkitsky Island. In this regard, we assert the necessity to revise the existing boundaries of the Gydansky State Nature Reserve by including into the Protected Area the following sites: Vilkitsky Island together with the Vostochnaya Spit and Shvede Bay, the Neupokoev Island together with the Neupokoeva Spit and water areas adjacent to these islands at a distance of 5 km from the coastline.