Evaluating structural landscape development in the municipality Upplands-Bro, using landscape metrics indices

Sammanfattning: The aim of this study was to evaluate and describe the landscape development in an area located in the municipality of Upplands-Bro, Sweden. The main hypothesis was that the landscape patterns in the study area have changed, as I expected to discover that the landscape has undergone structural changes, in form of both changed land use and changed landscape patch composition. The hypothesis was based on the general landscape trend according to previous research, which says that landscapes worldwide, generally become less homogeneous and more fragmented. Not least in areas like the study area, which is located in the vicinity or in connection with already existing urban environments or developing communities. The aim was achieved through land use interpretation of orthophotos and implementation of different landscape indices. The interpretation and implementation of indices made it possible to quantify and analyse the landscape change over the studied time period 1960-2015. The study mainly comprises areas in and adjacent to the town Kungsängen, north east of Stockholm, Sweden. Digital land use vector maps that show land use 1960, 1975, 1995 and 2015 were created in GIS. The landscape development was evaluated using the landscape indices Patch density, Patch area mean, S1 and S2. The objective of implementing the landscape indices, was to compare how the distribution and geometry structure of different land use patches in the study area changed over time. The Shannon Diversity Index was implemented to measure how the landscape diversity in the study area changed over time. The results of the landscape evaluation showed as expected, that the landscape in the study area has undergone structural changes under the studied period. The study concluded that there has been both a redistribution of land use and changed landscape patch composition in the study area. 31% of the total study area has had changed land use between the years 1960-2015. Over the observed period, it is possible to discern that the proportions of built-up areas and open land/pasture has increased while the proportions of forest and agriculture areas has decreased. Mainly has the land use change been concentrated to the eastern parts of the study (in the surroundings to Kungsängen), although it is possible to discern land use change in areas throughout the hole study area. The most distinctive land use development trend observed was 1), a high percentage increase in built-up areas, mainly in areas adjacent to already existing built-up areas, and 2), a large percentage decline in agricultural areas. A decrease that is largely linked to the expansion of built-up areas. For each observed year has the landscape become more fragmented, in terms of patch density. The landscape patches have also become more complex in their form. Complexity of the patch is a measure that describes how a patch deviate from an isodiametric form. The landscape development in the study area in Upplands-Bro municipality reflects the general landscape development trend that takes place in many other areas and regions around the world. Not least in near urban areas in regions that have experienced a high development and population increase. The study also showed how implementation of landscape metrics can be used when analysing landscape development and evaluating how patterns in the landscape changed over time.