Landscape fragmentation caused by transportation infrastructure and built-up areas has a number of ecological effects. It contributes significantly to the decline and loss of wildlife populations and to the increasing endangerment of species in Europe, for example through the dissection and isolation of populations, and affects the water regime and the recreational quality of landscapes. In spite of the planning concept of preserving large unfragmented areas, fragmentation has continued to increase during the last 20 years, and many more new transportation infrastructure projects are planned, in particular in eastern Europe, which will further increase the level of landscape fragmentation significantly. Therefore, data on the degree of landscape fragmentation are needed that are suitable for comparing different regions, especially in relation to different natural landscape types and different socioeconomic conditions. This report quantitatively investigates the degree of landscape fragmentation in 28 countries in Europe for the first time for three different fragmentation geometries at three levels. The three levels include countries, regions (NUTS‑X, according to the Nomenclature of Statistical Territorial Units), and a grid of 1 km2 cells (LEAC grid, which is used for Land and Ecosystem Accounting activities).
The report applies the method of 'effective mesh density' which quantifies the degree to which the possibilities for movement of wildlife in the landscape are interrupted by barriers. The effective mesh density values across the 28 investigated countries cover a large range, from low values in large parts of Scandinavia to very high values in western and central Europe. Many highly fragmented regions are located in Belgium, the Netherlands, Denmark, Germany, France, Poland and the Czech Republic. High fragmentation values are mostly found in the vicinity of large urban areas and along major transportation corridors. The lowest levels of fragmentation are usually associated with mountain ranges or remoteness. Fragmentation geometry B2 'Fragmentation of non-mountainous land areas' which includes highways up to class 4, railways and urban areas, is the most important fragmentation geometry, as it is suitable for comparing regions with differing geographical conditions like different amounts of mountains or lakes; it also encompasses the most complete set of physical barriers that may affect a large number of species.
Predictive models of landscape fragmentation
In the second part, this report investigates potential causes that contribute to an increased or decreased degree of landscape fragmentation and determines their relative importance. The density of the transportation network and the extent of landscape fragmentation are largely a function of interacting socioeconomic drivers such as population density and geophysical factors such as topography. Current levels of landscape fragmentation need to be interpreted within the context of these regional socioeconomic and geophysical conditions. Therefore, this report applies a set of statistical models to determine which of these factors drive the process of landscape fragmentation in Europe. We analysed the statistical relationships between landscape fragmentation and a range of predictive variables, applied these relationships to predict the likely fragmentation values for all regions in our study area, and compared actual values with predicted values.
In general, the most relevant variables affecting landscape fragmentation were population density, gross domestic product per capita, volume passenger density, and the quantity of goods loaded and unloaded per capita. The amount of variation in the level of fragmentation that was explained by the predictor variables was high, ranging from 46 % to 91 % in different parts of Europe. The statistical relationships indicated that different drivers of landscape fragmentation are important in different parts of Europe. Efforts for curtailing landscape fragmentation should take these differences into account.