Бидний тухай
Багш ажилтан
Grassland insects face some of the most severe declines in species diversity and total abundance, in part due to agriculture. Livestock grazing is the largest agricultural land use in Mongolia that can have both positive and negative effects on insect communities. Here, we provide an assessment of rare and charismatic insects that can serve as a baseline for monitoring future population changes of selected species in the nature reserve. A total of 20 species were chosen including three species of dragonflies/damselflies (Odonata), two species of grasshoppers (Orthoptera), one species of true bug (Hemiptera), one species of lacewing (Neuroptera), nine species of beetles (Coleoptera), one species of ant (Hymenoptera), and three species of butterflies (Lepidoptera), and we discussed the future conservation issues in this nature reserve, where protection of existing habitat should be the primary goal for insect conservation.
This is the first comprehensive study based on a planned and intensive sampling eff ort that describes the community composition of insects in Khar Yamaat Nature Reserve, Mongolia. As part of ongoing research project in the reserve, we recorded 341 insect species representing 9 orders and 70 families. Coleoptera represented the most speciose order (171 spp.) followed by Lepidoptera (44 spp.) and Orthoptera (33 spp.), whereas Odonata (4 spp.) and Neuroptera (5 spp.) were the least specious. At the family level, the ground beetles (Carabidae, 43 spp.), leaf beetles (Chrysomelidae, 30 spp.), grasshoppers (Acrididae, 25 spp.), and weevil beetles (Curculionidae, 22 spp.) were the most species rich among other families. We selected six ground-dwelling beetle groups for the study of their post-fi re succession, and their activity densities among different years after the wildfire were not significantly different. The trophic guilds of selected beetles did not differ much among the years after the wildfire, and across the years, predators were more abundant than the other feeding types. The number of dominating species has fluctuated greatly in the years after the wildfire.
We studied the community structure of dung beetles in livestock dung within the steppe ecosystem of Mongolia. We found 15 species of dung beetles belonging to three families and representing two functional guilds, namely paracoprids and endocoprids. All species were found in the horse dung, but only 11 species inhabited cow dung, and except Geotrupes koltzei none of these species seemed linked exclusively to one kind of dung. A few species dominated the communities, specifi cally Aphodius comma, Aphodius altaicus and Aphodius antiquus. Among these, Aphodius comma was the predominant species, occupying 44.4% of total surveyed dungs. Species richness, biomass, and abundance of beetles per dung were signifi cantly higher in horse dung than cow dung. Abundance of beetles was signifi cantly higher in the middle of summer than in late summer, but species richness was not signifi cantly diff erent between the middle of and late summer. This study constitutes one of the fi rst eff orts to systematically understand dung beetle assemblages in the steppe of Mongolia, including the eff ects of dung types and environmental gradients on beetle communities.
The Mongolian marmot (Marmota sibirica) is a large, endangered rodent species that ranges across the steppe regions of Mongolia, and parts of China and Russia. Marmot lives colonially and creates extensive burrow systems that change the soil nutrient profiles and influence plant and animal community composition and productivity. We examined the role of marmots on the diversity and abundance of ground-dwelling and flying insects. We hypothesize that the arthropod communities differ between marmot colonies and surrounding grasslands in diversity and abundance. We trapped 4765 individuals of arthropods representing 178 species of insects and 12 families of spiders. Marmot colony sites differed significantly from off colony sites by communities of ground-dwelling and flying insects. Our findings indicate that abundance and species richness of arthropods are largely associated with marmot burrows, which might be a reason for increased habitat heterogeneity, such as bare ground, specific vegetation structure, and thermoregulatory site by ecosystem engineering. Our results demonstrate that the marmots are keystone species in arid ecosystems, and have complementary, additive effects on steppe arthropod communities.
