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Biodiversity in the wake of urban sprawl: loss among epiphytic lichens on large oaks
Södertörn University, School of Life Sciences, Environmental science. Södertörn University, School of Life Sciences, Biology.
Linköpings universitet, Ekologi.
Linköpings universitet, Institutionen för fysik, kemi och biologi.
Linköpings universitet, Institutionen för fysik, kemi och biologi.
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(English)Manuscript (preprint) (Other academic)
Abstract [en]

Biodiversity often suffers from urbanisation. In the present study, we focused on how the age of urbanisation affects the richness of 17 epiphytic lichens species and their cover on large oaks, with a minimum spacing of 250 m, in urban environments in the city of Linköping (100,000 inhabitants), SE Sweden. We also surveyed trees in adjacent rural areas, selected to have similar distributions of tree trunk circumference and oak density within 300 m. Lichen richness and cover were significantly lower on urban trees compared to rural trees. Furthermore, richness and cover decreased with the length of time that urban trees had been surrounded by houses. Roughly one species is lost every 30 years. Most of the species that were analysed demonstrated a drop in occurrence with respect to the duration of housing development. The reduction in the probability of occurrence varied from 60% (Calicium viride, Evernia prunastri), 80% (Chrysotrix candelaris) to 90% (Ramalina spp.) during the 160-year period of urbanisation considered. Therefore, even if valuable trees survive over the course of development, their lichen flora are likely to become depleted over time.

Keyword [en]
Housing; landscape; Linköping; Quercus; spatial; urbanization
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:sh:diva-17074OAI: oai:DiVA.org:sh-17074DiVA: diva2:553149
Note

Som manuskript i avhandling. As manuscript in dissertation.

Available from: 2012-09-14 Created: 2012-09-18 Last updated: 2012-11-01Bibliographically approved
In thesis
1. Studies on spatial and temporal distributions of epiphytic lichens
Open this publication in new window or tab >>Studies on spatial and temporal distributions of epiphytic lichens
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Lichens are an important group of organisms in terms of environmental issues, conservation biology and biodiversity, principally due to their sensitivity to changes in their environment. Therefore it is important that we develop our understanding of the factors that affect lichen distribution. In this thesis, both spatial and temporal distributions of epiphytic lichens at different scales have been studied in southern Sweden.

Generation time of the red-listed lichen Cliostomum corrugatum was examined using Bjärka-Säby as the study site. The results showed that the average age of an individual of C. corrugatum is 25–30 years at the onset of spore production.

The rarity of C. corrugatum was also examined. DNA analysis of an intron from 85 samples, collected at five sites in Östergötland, yielded 11 haplotypes. Results from coalescent analysis, mantel test and AMOVA indicated that C. corrugatum have a high ability to disperse. The study concluded that its rarity is most likely connected with the low amount of available habitat, old Quercus robur.

The changes in the distribution of epiphytic lichens in southern Sweden, between 1986 and 2003, were also compared. For each year a centroid was calculated on all combinations of tree and lichen species. The three significant cases showed that the centroid movement pointed toward a north-east or north-north-east direction.

Finally differences in species richness and cover of lichens on large Q. robur were examined between urban and rural environment. The results demonstrated that species number and percent cover was significantly higher on oaks standing rural compared to oaks standing urban. Effects of urban sprawl showed a decline in species richness and cover with increasing age of the surrounding buildings.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2012. 42 p.
Series
Södertörn Doctoral Dissertations, ISSN 1652-7399 ; 72
Series
, Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1471
National Category
Environmental Sciences
Identifiers
urn:nbn:se:sh:diva-17075 (URN)978–91–7519–810–1 (ISBN)
Public defence
2012-10-22, Plank, Fysikhuset, Campus Valla, 10:00 (Swedish)
Opponent
Supervisors
Available from: 2012-09-18 Created: 2012-09-18 Last updated: 2014-12-22Bibliographically approved

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