Small biotopes in agricultural landscapes: importance for vascular plants and effects of management
Author
Summary, in English
As a consequence of agricultural intensification, large areas of non-crop habitat have been lost and farmland biodiversity has declined. Previous studies have shown that the extent of non-crop habitat influences farmland biodiversity, but the relative importance of different habitat types is less well known and the contribution of small incidental habitats to landscape-scale species richness is not fully understood. In the thesis, I have examined the importance of small biotopes (uncultivated field margins, ditches, marl pits, road verges etc.) to landscape-scale richness of vascular plants within agricultural landscapes of varying complexity. I sampled vascular plants within five different habitat types and calculated the relative contribution of each habitat type to overall species richness. The results showed that small biotopes are highly important for the preservation of vascular plants within agricultural landscapes. Small biotopes contained a majority of the species that were found within each study site and contributed considerably more than their relative area to total species richness. Plant species used as pollen and nectar resources by bees were found in the same relative proportions within the different habitat types as all vascular plants, but the extent to which the habitat types were used as pollen resources varied over the season and between bee taxa. I also used data from the regional flora for Scania to model the importance of different types of non-crop habitat for total and grassland species richness within 6.25 km2-sites in agricultural landscapes of varying complexity. Within the most simplified landscapes, landscape-scale species richness (all species and grassland species) was mainly determined by the most widespread non-crop habitat types, whereas the extent of small biotopes influenced landscape-scale species richness within the more complex agricultural landscapes.
Historically Swedish small biotopes were kept open by grazing and haymaking, but after the traditional management was abandoned a gradual encroachment of woody vegetation began. Concern that the increase in woody vegetation would adversely affect the biological and cultural values of small biotopes lead to the establishment of a Swedish agri-environment schemes (AES)which stipulated farmers to keep small biotopes on their property free from woody vegetation. In the thesis I have evaluated to what extent the biological values of small biotopes are influenced by the prescribed management. To this end, I compared the flora (richness and species composition of vascular plants) of open and overgrown field margins. I found no indication that non-woody plant species benefited from the removal of woody vegetation as prescribed by the AES for small biotopes. Taking measures to counteract eutrophication, in combination with field layer management of the least impoverished small biotopes,is therefore more likely to enhance the floristic values of small biotopes than the removal of woody vegetation alone.
Historically Swedish small biotopes were kept open by grazing and haymaking, but after the traditional management was abandoned a gradual encroachment of woody vegetation began. Concern that the increase in woody vegetation would adversely affect the biological and cultural values of small biotopes lead to the establishment of a Swedish agri-environment schemes (AES)which stipulated farmers to keep small biotopes on their property free from woody vegetation. In the thesis I have evaluated to what extent the biological values of small biotopes are influenced by the prescribed management. To this end, I compared the flora (richness and species composition of vascular plants) of open and overgrown field margins. I found no indication that non-woody plant species benefited from the removal of woody vegetation as prescribed by the AES for small biotopes. Taking measures to counteract eutrophication, in combination with field layer management of the least impoverished small biotopes,is therefore more likely to enhance the floristic values of small biotopes than the removal of woody vegetation alone.
Department/s
Publishing year
2015
Language
English
Document type
Dissertation
Publisher
Lund University, Faculty of Science
Topic
- Ecology
- Physical Geography
Keywords
- Small biotopes
- incidental habitat
- vascular plants
- woody vegetation
- grassland species
- resource provisioning
- species richness
- habitat specificity
- non-crop habitat
- landscape complexity
- heterogeneity
- local management
- agri-environment scheme
Status
Published
Supervisor
ISBN/ISSN/Other
- ISBN: 978-91-7623-276-7
- ISBN: 978-91-7623-275-0
Defence date
17 April 2015
Defence time
09:30
Defence place
Blue Hall, Ecology Building, Sölvegatan 37, Lund
Opponent
- Doreen Gabriel