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Djodjic F.,Swedish University of Agricultural Sciences | Spannar M.,County Administrative Board of Dalarna
Acta Agriculturae Scandinavica Section B: Soil and Plant Science | Year: 2012

Identification of main contributing sources and critical source areas is a precondition for a cost-effective abatement strategy. This task is even more complicated in small ungauged catchments where inadequate amount of input, calibration, and validation data exists and thereby limit the application of process-based, parameter-heavy models. In this study, we present methodology to assess spatial variations in erosion and P losses, and based on source-apportionment and erosion modeling, to develop a base for source and site-specific abatement countermeasures. Water quality monitoring program was developed to cover spatial variability in erosion and phosphorus (P) losses. Conducted soil survey detected high variations in soil P content within the catchment and strong correlation between soil P test and easily soluble P. A simple water balance model, calibrated for the comparable catchment with existing water flow measurements, was applied to determine water discharge, providing necessary input data for calculations of loads and source-apportionment. Source-apportionment modeling based on results from water discharge modeling, water quality monitoring program and soil survey identified P losses from arable fields as main source of P to two small lakes situated in the catchment, contributing roughly a half of total P load to the lakes. Inclusion of an assumed but previously undocumented point source considerably improved the performance of source-apportionment model. Existence of such a point-source was afterwards confirmed by results from detailed water quality monitoring program. Erosion modeling based on high-resolution digital elevation data identified areas most prone to erosion, and model results were compared to farmers' observations and analyses of 137Cs. Use of a spectrum of models and assessment tools formed a broad support for further steps in abatement efforts, and created concrete discussion base for implementation of detailed site-specific countermeasures. © 2012 Copyright Taylor and Francis Group, LLC. Source


Jonsson M.T.,Swedish University of Agricultural Sciences | Ruete A.,Swedish University of Agricultural Sciences | Kellner O.,County Administrative Board of Gavleborg | Gunnarsson U.,County Administrative Board of Dalarna | Snall T.,Swedish University of Agricultural Sciences
Biodiversity and Conservation | Year: 2016

Incorporating functional values in biodiversity monitoring systems could add novel perspectives of the status of biodiversity in conservation areas. Stable frequencies of large foliose nitrogen-fixing cyanolichens likely have positive effects on the nitrogen budget of forests and provide food, material and shelter for invertebrates, gastropods and birds. Stable volumes of deadwood and frequencies of associated fungi provide an important supporting function for ecosystem services such as nutrient cycling, carbon storage and soil formation. Based on regional monitoring data from boreal old-growth forest nature reserves and key habitats, we tested for changes in the frequency of various functionally important substrates and species over time. We detected significant reductions in the frequency of indicator cyanolichens occurring on deciduous trees already after 10 years in key habitats, despite non-significant changes in their host substrates. Frequencies of indicator pendulous lichens Alectoria sarmentosa and Bryoria nadvornikiana had also decreased in key habitats, despite overall stable volumes of large conifer host trees. Lichen reductions were more pronounced in the smaller key habitats compared to the larger formally protected nature reserves, likely due to degrading fragmentation and isolation effects. In contrast to these lichens, the average frequencies of old-growth forest indicator fungi decaying coniferous deadwood and common fungi on deciduous trees (Fomes fomentarius) and coniferous trees (Fomitopsis pinicola) remained unchanged. The studied cyanolichens and fruiting fungi generally had similar extinction rates over 10 years, whilst only cyanolichens had substantially lower colonization rates. Amid a severely fragmented landscape, conservation areas seem to struggle in preserving some of the basic old-growth forest values. © 2016 Springer Science+Business Media Dordrecht Source

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