Browsing by Author "Joharchi O"

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    Landscape gradients in Sphagnum peatlands: Nutrients, trace elements and diversity of free-living mites (Arthropoda: Acari) along a 1600 km transect on the West Siberian Plain
    (Elsevier B.V., 2024-09-24) Minor MA; Sheykin SD; Stolbov VA; Ermilov SG; Joharchi O; Afonin AS; Shvartseva OS; Tolstikov AV
    The West Siberian Plain holds special ecological significance as the largest peatland region of the world, which is expected to be affected by the climate change. We analysed water chemistry, chemical composition of Sphagnum tissues (total C, total N, K, P, and a range of trace elements) and biodiversity (abundance, species richness, community composition) of free-living mites (Oribatida and Mesostigmata) in twelve Sphagnum peatlands along the 1600 km transect (54°46′N to 67°29′N) on the West Siberian Plain. Mites were classified into two functional groups – “limnic” (Oribatida species which inhabit aquatic habitats), and “terrestrial” (all other species). The results showed a latitudinal productivity gradient, with a consistent increase in nutrient content of Sphagnum and water pH from North to South; the northern-most site had lowest N and highest C:N ratio, indicating potential N limitation. There was an increase in levels of Cr, Zn, Ni and Sr in the Sphagnum tissues in proportion to the abundance of lithophile Ti on the southern end of the transect; however, in absolute terms, the concentrations of these elements were low. The abundance patterns of terrestrial and limnic mites reflected increasing nutrient load in Sphagnum bogs from North to South, as well as increasingly xeric conditions. Latitude and nutrients (P and C:N ratio) together explained 67.2 % variability in community composition of Oribatida and Mesostigmata. We found no effect of latitude or productivity on species richness; the main driver for species richness appeared to be the local micro-topography, with dryer areas colonised by a wider range of species. Our data help to elucidate landscape-scale patterns of productivity and biodiversity in West Siberian peatlands and provide a checkpoint in the timeline of global change. As sensitive intrazonal ecosystems, peatlands can act as useful early warning systems, offering insights about the effects of human activities on a large scale.
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    Using spectral indices derived from remote sensing imagery to represent arthropod biodiversity gradients in a European Sphagnum peat bog
    (MDPI (Basel, Switzerland), 2023-03) Minor MA; Ermilov SG; Joharchi O; Philippov DA; Oliveira Júnior JMB
    Monitoring of peatlands is an important conservation issue. We investigated communities of soil mites (Acari: Oribatida, Mesostigmata) inhabiting a relatively undisturbed European boreal mire characterized by a mosaic of oligotrophic and meso-eutrophic areas. We assess the potential of using remote sensing approach as a mapping and predictive tool for monitoring productivity and arthropod biodiversity in a peat bog. In georeferenced plots, Acari biodiversity, water table level, water pH and plot productivity class on the oligotrophic-eutrophic gradient were recorded. Data from the Landsat 8 OLI sensor were used to calculate several spectral indices known to represent productivity and surface moisture gradients in terrestrial ecosystems. We then explored the relationship between spectral indices, environmental gradients and biodiversity of mites. We found that several spectral indices were significantly and consistently correlated with local environmental variables and biodiversity of soil mites. The Excess Green Index performed best as a predictor of plot trophic class on the oligotrophic-eutrophic gradient and showed significant relationship with Oribatida diversity in 2016. However, following hot summer in 2019, there was no significant relationship between abundance and species richness of Oribatida and remotely sensed data; there was a weak correlation between abundance of Mesostigmata and spectral indices which represent surface moisture gradient (e.g., Normalised Difference Moisture Index). We discuss advantages and challenges of using spectral indices derived from remote sensing imagery to map biodiversity gradients in a peatland.