67 research outputs found
Modelling and simulating change in reforesting mountain landscapes using a social-ecological framework
Natural reforestation of European mountain landscapes raises major environmental and societal issues. With local stakeholders in the Pyrenees National Park area (France), we studied agricultural landscape colonisation by ash (Fraxinus excelsior) to enlighten its impacts on biodiversity and other landscape functions of importance for the valley socio-economics. The study comprised an integrated assessment of land-use and land-cover change (LUCC) since the 1950s, and a scenario analysis of alternative future policy. We combined knowledge and methods from landscape ecology, land change and agricultural sciences, and a set of coordinated field studies to capture interactions and feedback in the local landscape/land-use system. Our results elicited the hierarchically-nested relationships between social and ecological processes. Agricultural change played a preeminent role in the spatial and temporal patterns of LUCC. Landscape colonisation by ash at the parcel level of organisation was merely controlled by grassland management, and in fact depended on the farmer's land management at the whole-farm level. LUCC patterns at the landscape level depended to a great extent on interactions between farm household behaviours and the spatial arrangement of landholdings within the landscape mosaic. Our results stressed the need to represent the local SES function at a fine scale to adequately capture scenarios of change in landscape functions. These findings orientated our modelling choices in the building an agent-based model for LUCC simulation (SMASH - Spatialized Multi-Agent System of landscape colonization by ASH). We discuss our method and results with reference to topical issues in interdisciplinary research into the sustainability of multifunctional landscapes
The importance of sedimenting organic matter, relative to oxygen and temperature, in structuring lake profundal macroinvertebrate assemblages
We quantified the role of a main food
resource, sedimenting organic matter (SOM), relative
to oxygen (DO) and temperature (TEMP) in structuring
profundal macroinvertebrate assemblages in
boreal lakes. SOM from 26 basins of 11 Finnish lakes
was analysed for quantity (sedimentation rates),
quality (C:N:P stoichiometry) and origin (carbon
stable isotopes, d13C). Hypolimnetic oxygen and
temperature were measured from each site during
summer stratification. Partial canonical correspondence
analysis (CCA) and partial regression analyses
were used to quantify contributions of SOM, DO and
TEMP to community composition and three macroinvertebrate
metrics. The results suggested a major
contribution of SOM in regulating the community
composition and total biomass. Oxygen best explained
the Shannon diversity, whereas TEMP had largest
contribution to the variation of Benthic Quality Index.
Community composition was most strongly related to d13C of SOM. Based on additional d13C and stoichiometric
analyses of chironomid taxa, marked differences
were apparent in their utilization of SOM and
body stoichiometry; taxa characteristic of oligotrophic
conditions exhibited higher C:N ratios and lower C:P
and N:P ratios compared to the species typical of
eutrophic lakes. The results highlight the role of SOM
in regulating benthic communities and the distributions
of individual species, particularly in oligotrophic
systems
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