The current capacity for the purposeful study of the mammalian fauna of Russia using public databases is discussed. A list of species of Russian fauna compiled under united principles is lacking and the lists of species published in different departments are inconsistent. Systems that can monitor changes in the qualitative or quantitative composition of the fauna are not yet sufficiently refined. The systematization of previously accumulated faunal data requires the involvement of qualified taxonomists. Nevertheless, initial work on the “Mammals of Russia” database, which currently contains 16 512 records on 235 species of mammals, has allowed us to positively assess the prospects for further ordering of faunal information within the country.
Testate amoebae are important components of benthic communities in freshwater lakes, where they play an essential role in decomposer food webs. They are used widely in paleoecological investigations because of their high taxonomic diversity, well-defined ecological preferences and decay-resistant tests. Studies of testate amoeba assemblages in lake surface sediments are necessary to better understand lake ecosystem function and improve the use of these organisms as bio-indicators in paleoecology. This study explored the use of testate amoebae as proxies for inferring past water level in freshwater lakes, and expanded upon the limited body of research into lake testate amoebae in Russia. Our results indicate that species composition of testate amoeba assemblages in the lakes was typical for such biotopes, with most of the species belonging to the genera Difflugia, Centropyxis, Arcella and Euglypha. Analysis of variation of testate amoebae along a water-depth gradient showed that three assemblage types could be distinguished: shallow-water (0–4.5 m), intermediate-water-depth (4.5–20.5) and deep-water (20.5–33 m). Deep-water assemblages did not contain any unique taxa and were dominated by eurybiotic and planktonic species. Species diversity was highest in the intermediate-water-depth assemblages and lowest in deep-water ones. Although variations in testate amoeba assemblages across water depth in freshwater lakes are complex and context-dependent, there are clear patterns in species composition and diversity, which can be used to infer past lake water levels. Future studies on the effect of water depth on testate amoeba assemblages in diverse types of freshwater lakes should increase the utility of the method.
Fifty-two species and intraspecific taxa of testate amoebae have been detected in 24 different habitats in the Belaya River basin (Northwestern Caucasus). Four types of communities are distinguished which differ in the composition of the complex of dominating species: freshwater species from bottom sediments in water bodies and water courses, soil-dwelling species from inundated parts of floodplains, a mixture of soildwelling and freshwater species in different littoral biotopes, and eurybiontic species in moss hummocks along the banks.
Population dynamics is a field rich in theory and poor in long‐term observational data. Finding sources of long‐term data is critical as ecosystems around the globe continue to change in ways that current theories and models have failed to predict. Here we show how long‐term ecological data can improve our understanding about palaeo‐population change in response to external environmental factors, antecedent conditions and community diversity.
We examined a radiometrically dated sediment core from the Didachara Mire in the mountains of south‐western Georgia (Caucasus) and analysed multiple biological proxies (pollen, fern spores, non‐pollen palynomorphs, charcoal, diatoms, chrysophyte cysts, midges, mites and testate amoebae). Numerical techniques, including multivariate ordination, rarefaction, independent splitting and trait analysis, were used to assess the major drivers of changes in community diversity and population stability. Integrated multi‐proxy analyses are very rare in the Caucasus, making this a unique record of long‐term ecological change in a global biodiversity hotspot.
Synthesis. Population changes in the terrestrial community coincided primarily with external environmental changes, while populations within the peatland community were affected by both internal and external drivers at different times. In general, our observations accord with theoretical predictions that population increases lead to greater stability and declines lead to instability. Random variation and interspecific competition explain population dynamics that diverged from predictions. Population change and diversity trends were positively correlated in all taxonomic groups, suggesting that population‐level instability is greater in more diverse communities, even though diverse communities are themselves more stable. There is a continuing need to confront population theory with long‐term data to test the predictive success of theoretical frameworks, thereby improving their ability to predict future change.
We investigated how the land-use change from rainforest into jungle rubber, intensive rubber and oil palm plantations affects decomposers and litter decomposition in Sumatra, Indonesia. Litterbags containing three litter types were placed into four land-use systems and harvested after 6 and 12 months. Litter mass loss and litter element concentrations were measured, and different microbial groups including bacteria, fungi and testate amoebae were studied. After 12 months 81, 65, 63 and 53% of litter exposed in rainforest, jungle rubber in oil palm and rubber plantations was decomposed. In addition to land use, litter decomposition varied strongly with litter type and short-term effects differed markedly from long-term effects. After 6 months, oil palm and rubber litter decomposed faster than rainforest litter, but after 12 months, decomposition of rainforest litter exceeded that of oil palm and rubber litter, reflecting adaptation of bacteria and fungi to decompose structural compounds in rainforest litter but not (or less) in rubber and oil palm litter. Bacterial and fungal community composition and testate amoeba species number and density varied strongly with litter type, but little with land use. However, community composition of testate amoebae was mainly affected by land use. Generally, changes in bacteria, fungi and testate amoebae were linked to changes in litter element concentrations, suggesting that element ratios of litter material as basal resource for the decomposer food web shape the structure of decomposer communities and decomposition processes via bottom-up forces. Overall, changing rainforest to monoculture plantations shifts the decomposer community structure and negatively affects litter decomposition.