Land use intensity and landscape complexity - analysis of landscape characteristics in an agricultural region in Southern Sweden.

摘要

It is generally recognised that agricultural intensification has lead to simplification of landscape structure, but it has not been clarified if this is a ubiquitous relationship. That is, it has been an open question whether agricultural intensity and landscape simplicity should be regarded as one single or as two separate dimensions. To evaluate this we analysed landscape data in 136 different 1 km x 1 km study sites and within a buffer zone of 2 km around each site (i.e. approximately 5 km x 5 km). The sites were distributed over a large part of the region of Scania, southernmost Sweden, an area dominated by agriculture but with large variation in both intensity and complexity. We used spatially explicit digital data on land use, digitised aerial photographs, field surveys of landscape elements and agricultural statistics. Two separate factor analyses, one for each scale of measurements (1 km and 5 km), suggest that there are five and three relevant factors for each scale respectively. At the 1 km scale, the first factor can be interpreted as describing the intensity of land use in the form of proportion arable land which is highly correlated to crop yield. The second and third factors are more connected to landscape structure and amount of small patches of semi-natural habitats. The fourth and fifth factors contain one major variable each: proportion pasture and leys respectively. The division of intensity and complexity related variables is less clear at a larger spatial scale. At the 5 km scale, factor 1 is defined almost identically as at the 1 km scale. However, factors 2 and 3 are interpreted as descriptors of dairy and livestock farming systems but also include structural variables. Our analyses suggest that land use intensity and structural complexity of landscapes are more or less separate landscape level factors, at least at smaller spatial scales. This is important to bear in mind, especially when trying to explain patterns of biodiversity change in agricultural landscapes.