Cross-European landscape analyses: illustrative examples using existing spatial data
Thirty-nine landscape metrics related to (1) conditions of terrestrial habitat, water quality, and ecosystem productivity, (2) potential pressures on or stresses to environmental resources, and (3) changes in conditions, were generated for Europe from existing spatial data. The core land cover data used were available at resolution scales of 1 km (International Geosphere Biosphere Program or IGBP) and 100 m (Corine). These core data were used to calculate landscape metrics on water catchments (average area of approximately 2,500 km2 for 1,888 catchments) and on 64 km2 areas to capture finer-scale patterns. We also calculated the same metrics using finer-scale landscape data on the Yantra River Basin of north-central Bulgaria, permitting a comparison to broader-scale results from across Europe. We found that data to calculate all of the metrics did not exist for all of Europe and this resulted in analysis of two different spatial extents of Europe and different mixes of metrics in the landscape analyses. The Corine data set did not cover all of Europe but where it existed it was available for the approximate periods of 1990 and 2000. Greenness (Normalized Difference Vegetation Index or NDVI) estimates were available for all of Europe for approximately the same time period (1992- 2003), but at a resolution scale of 64 km2. These data sets in total offered an opportunity to compare results for the different metric sets used, and different spatial scales and changes in values between sample times. The results showed some differences in several key metrics between the different data sets but that it was possible to map areas with regards to relative condition with reasonable agreement. As expected the 64 km2 analysis units showed greater detail and variation in landscape conditions and change than did catchments. However, the relatively course-scaled nature of the stream and river database for Europe precluded an analysis of riparian habitat conditions on the 64 km2 areas. Overall changes in the landscape metric values between the 1990 and 2000 sample times were small, but there was considerable spatial variation in the amount of gain or loss. For example, relatively large percent gains in forests were observed in Spain, southern France, and in east-central Europe, whereas relatively large percent losses were observed in southwest France and western Spain. Forest change was inversely associated (from most to least important) with changes in shrubland, total agriculture, grassland, and urban land cover (p < 0.05). Agriculture lands were inversely (in decreasing order of importance) associated with changes in grassland, forest, shrubland, and urban land cover. However, because the Corine 1990 and 2000 databases were created from different methodologies, the change results must be interpreted with caution. On average, Europe became significantly greener between 1992 and 2003. Significant (p < 0.05) positive trends in greenness were observed across Europe, but in larger patches in eastern Spain, Wales and Scotland (UK), and in Romania. Significant negative trends were observed in southern Spain and southwestern Russia along the Caspian Sea. Trends in greenness and land cover change were uncorrelated. Results from the European-wide analyses of the Yantra River Basin compared favorably to the more detailed analyses that were based partially on finer resolution biophysical data. However, estimates for riparian land cover metrics were much higher for the more detailed analyses than the broader-scale analyses, a result of a denser stream network used in the former. Additionally, because of differences in the scale of Digital Elevation Model data used in the two analyses (90 m and 25 m), estimates for agriculture on greater than 3% slopes differed as well. A principal components analysis (PCA) was used to combine multiple landscape metrics to evaluate the relative environmental condition of and change in catchments and the 64 km2 areas. Additionally, a simple index of relative vulnerability was calculated and mapped by combining PCA results for landscape condition and change. We discuss results and limitations of this analysis. We also discuss the value of this preliminary assessment for broadscale analyses to identify geographic areas where environmental security may become an issue. We note limitations in the analytical techniques used, data gaps and issues regarding interpretation of these results and make suggestions for future landscape analyses.
Keywords: Landscape metrics; European landscape analysis; integrated analysis; catchments; goods and services
KeywordsLand Cover Normalize Difference Vegetation Index Grid Cell Geographic Information System Land Cover Change
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