RESUMEN
The relationship between species diversity and spatial scale is a central topic in spatial community ecology. Latitudinal gradient is among the core mechanisms driving biodiversity distribution on most scales. Patterns of ß-diversity along latitudinal gradient have been well studied for aboveground terrestrial and marine communities, whereas soil organisms remain poorly investigated in this regard. The West Siberian Plain is a good model to address diversity scale-dependence since the latitudinal gradient does not overlap with other possible factors such as elevational or maritime. Here, we collected 111 samples following hierarchical sampling (sub-zones, ecosystem types, microhabitat and replicate samples) and performed multi-scale partitioning of ß-diversity of testate amoeba assemblages as a model of study. We found that among-ecosystem ß-diversity is a leading scale in testate amoeba assemblages variation. Rare species determine ß-diversity at all scale levels especially in the northern regions, where rare taxa almost exclusively accounted for the diversity at the ecosystem level. ß-Diversity is generally dominated by the turnover component at all scales in lower latitudes, whereas nestedness prevailed at among-ecosystem scale in higher latitudes. These findings indicate that microbial assemblages in northern latitudes are spatially homogeneous and constrained by historical drivers at larger scales, whereas in southern regions, it is dominated by the turnover component both at the microhabitat and ecosystem scales and therefore determined by recent vegetation and environmental heterogeneity. Overall, we have provided the evidence for the existence of negative latitudinal gradient for among-ecosystem ß-diversity but not for among-microhabitat and among-sample ß-diversity for terrestrial testate amoeba communities.
RESUMEN
Background: Testate amoebae are a polyphyletic group of unicellular eukaryotic organisms that are characterised by a rigid shell and inhabit mostly freshwater and terrestrial ecosystems. They are particularly abundant in peatlands, especially in Sphagnum-dominated biotopes. Peatland hydrology is the most important influence on testate amoebae communities. The good preservation of the shells in peat deposits and their response to hydrological regime changes are the principles for palaeohydrological reconstructions. Any changes in the water balance of mires should be expected to have far-reaching effects on biogeochemical cycles, productivity, carbon dioxide and methane exchange. New information: This paper presents a dataset (Darwin Core Archive - DwC-A) on the distribution of Sphagnum-dwelling testate amoebae in nine mires located in the forest-steppe subzone of the East European Plane. The dataset includes information about 86 taxa belonging to 29 genera and contains 3,123 occurrences of 49,874 individuals. The following environmental variables are provided: microtopography, oxidising and reducing potential, total mineralisation, substrate temperature, acidity, substrate wetness and water table depth. These data might be used for biogeographical and palaeoecological studies, including quantitative reconstructions.
RESUMEN
High-latitude peatlands are changing rapidly in response to climate change, including permafrost thaw. Here, we reconstruct hydrological conditions since the seventeenth century using testate amoeba data from 103 high-latitude peat archives. We show that 54% of the peatlands have been drying and 32% have been wetting over this period, illustrating the complex ecohydrological dynamics of high latitude peatlands and their highly uncertain responses to a warming climate.