Master thesis offers a close-up look at urban ecosystems
Julie Brastein Halvorsen recently defended her MSc thesis, titled "Characterisation and typification of urban ecosystem types: a test of the NiN system".
Julie in the field on a hot summer day.
The urban landscape hosts diverse ecosystems, many of which are strongly modified by humans while some are semi-natural or natural. Julie B. Halvorsen's close look at the urban ecosystems of Oslo, defined using the NiN system, shows that also strongly modified ecosystems can be distinguished by the plants that grow there.
Halvorsen's multivariate analysis (DCA and GNMDS) of species composition was based on her maps and botanical inventory of 201 plots along an urban-rural gradient from Oslo's city centre to the surrounding forest. She mapped these 10x10 m plots at 1:500 m scale using NiN ecosystem types, and recorded abundances of all vascular plant species in each of the mapped polygons in the plots.
Her results support the existing partitioning of strongly modified ecosystems in NiN, which is based mainly on substrate types and physical history. Environmental variables like elevation and temperature did not seem to affect the species composition, leaving human influence and soil properties as the most important determinants of urban vegetation patterns.
Julie's supervisors were Olav Skarpaas and Rune Halvorsen.