Historisk utvikling av grønnstruktur og bynær natur i Bergen kommune 1992 – 2022: Landsat 4 - 8 NDVI og landskapsanalyse

Urban green spaces are important components of cities. In a Norwegian context, these areas are large natural areas, accessible nature areas, parks and remnants of nature. Their function is important for both biodiversity and human wellbeing. Urbanization is an ongoing process and the resulting land use changes pose a threat to urban green spaces. Norway is a well-regulated society, and urban green spaces has been and is a part of the national and municipal area management. Historically, urban green space was an umbrella term. It eventually made its way into the current Plan and building act and its historical meaning was kept. Sustainability is a focus in Norwegian planning, but sustainability has many definitions. This study chose a landscape-focused view of sustainability, where sustainability is based on the ability of the landscape to maintain both ecological function and support human activities. In this context, urban green spaces consist of a lot more than just the areas zoned for that purpose and the question arises: What has happened to urban green spaces in Bergen between 1992 and 2022? This study seeks to answer this question using Landsat-derived NDVI remote sensing data with 30-meter spatial resolution and quantitative landscape analysis to examine the historical development of identifiable urban vegetation from 1992 to 2022. The study used Google Earth Engine to create composite NDVI time series mosaics. These mosaics were then used to determine the point when vegetated pixels had lasting change. The resulting dataset was used to detect the lost amount of urban vegetation and when it was lost. The study found that 38,2 km2 of the land area of Bergen municipality was covered by impervious surfaces at the end of 1995. From 1996 to 2022 an additional 34,4 km2 was covered by impervious surfaces. Areas that have traditionally been used for recreational purposes were maintained throughout the temporal scope of the study. The cumulative changes from the historical were used to create representations of landscapes from 1992 to 2022 with two classes, urban green spaces and impervious surfaces. A limited set of landscape metrics was chosen to examine the spatial dynamics over time. The results showed a general trend toward more consolidated impervious surfaces and resulting fragmentation of urban green spaces.

Masteroppgave i geografi

GEO350

MASV-MEHA

MPGEOGR

MASV-GEOG

MASV-PHYG