Tест-система визначення вмісту мангану у ґрунтах долини ріки Cамари дніпровської

Abstract

Forest litter plays an important role in the forest ecosystem. It influences chemical composition of a solution that enters the soil, regulates heat regime and water-physical characteristics of the forest soil. A litter contains organic matters at different stage of their decomposition and humification. The quantity of forest litter depends on the species composition, age, shape and type of stands, soil water regime, live soil cover, and other factors. Soil-inhabiting fauna are associated with the decomposition and transformation of dead organic substances into inorganic ones. Changes to forest floor microarthropod community structure may lead to changes in these processes. Many studies consider soil microarthropods as possible indicators of soil quality. \nThe study was conducted in the central part of Zhytomyr Polissya (Radomyshl Forest State Enterprise). Litter was sampled at the beginning of April, August, and November 2012 in the fresh piny-oak forests of the following age groups: cut forest, non-closed forest, young forest, middle-aged forest and mature forest. A sample was a square litter monolith sized 10×10 cm each (100 сm2) with the thickness of a monolith equaled the thickness of the litter. A total of 75 samples were examined: 5 age groups × 3 seasons × 5 sampling occasions. Microarthropod extraction was conducted using modified Tullgren funnels (diameter 15 cm) containing inserted wire mesh with cells 2×2 mm. An electrical bulb was used as a source of heat. Invertebrates dropped through the exit hole of the funnel into collecting bottles containing 70 % alcohol. Extraction time lasted two days. \nTo characterize the composition of invertebrate communities and their diversity, the following ecological indices were used: density, percentage relative abundance, a comparison of two samples with Student’s t-test, Shannon’s index of biodiversity, inverse of Simpson’s index, and index of similarity after Marczewski and Steinhaus. \nIn all litter samples, invertebrate communities were composed predominantly of mites (Acari) and springtails (Collembola), the representatives of microarthropods, which accounted for up to 98% of extracted animals. Among other extracted invertebrates were representatives of the following taxa: Arеnеae, Pseudoscorpionida, Annelida, Nematode, Centipedes, Coleoptera, Hymenoptera, and insects larvae. Mite population in all studied samples included Oribatid, Prostigmatid, Mesostigmatid, and Astigmatid mites. The relative contribution of these suborders to the total mite abundance changed slightly with forest age. The density of all litter-inhabiting mesofauna and its major groups in pine forests varies significantly during the year.\xa0\xa0 \nMean absolute density of litter invertebrates increased with the forest age. The difference between cut and middle-aged or mature stands was statistically significant. \nThe ratio between mites and springtails are grew with age of the forests. The difference between cut and middle-aged or mature stands, and between non-closed forest sites and middle-aged stands was statistically significant. \nAmong the litter microarthropods of all studied areas dominated prostigmatid, oribatida mites, and springtails. The structure of microarthropods’ community was changed with the forests age. The relative abundance of mesostigmata and astigmata mites increased. this changes between cut and middle-aged or mature forests were statistically significant.