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- Aguilera, Guillermo, et al.
(författare)
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Intensive management reduces butterfly diversity over time in urban green spaces
- 2019
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Ingår i: Urban Ecosystems. - : Springer Science and Business Media LLC. - 1083-8155 .- 1573-1642. ; 22:2, s. 335-344
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Tidskriftsartikel (refereegranskat)abstract
- Loss and fragmentation of semi-natural grasslands have had negative consequences for grassland biodiversity, such as butterflies. Urban parks and other urban green spaces have so far largely been overlooked as suitable butterfly habitats, although they could potentially sustain diverse butterfly populations over time. We analysed the temporal change in butterfly species assemblages in urban green spaces in the city of Malmö, Southern Sweden. We studied changes in species richness and abundance of butterflies between 2006 and 2015 in 20 public urban green spaces, characterized by different management regimes. We sampled butterflies in traditional parks with intense grass cutting regimes, in semi-natural grasslands mowed only a few times per year, and in un-managed or irregularly managed ruderal sites. We found a slight increase in the total number of butterfly species in the study area, but a general decline in local species numbers in urban green spaces. Traditional urban parks had the greatest loss of species over time, and altogether the lowest number of species. In contrast, semi-natural parks and ruderal sites had higher numbers of butterfly species and also lost fewer species over time. Our study shows that intensive management strategies in urban green spaces have a negative impact on butterfly assemblages over time. We suggest that less intensive management strategies can be used to create high-quality areas for flower-visiting insects in urban green spaces, possibly in combination with planting larval host plant species, depending on the park type and design.
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| 2. |
- Huuva, Ivan, et al.
(författare)
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Measurements of forest biomass change using L- and P-band SAR backscatter
- 2017
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Ingår i: International Geoscience and Remote Sensing Symposium (IGARSS). - 9781509049516 ; 2017-July, s. 5818-5821, s. 5818-5821
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Konferensbidrag (refereegranskat)abstract
- Three-year forest above-ground biomass change were measured using L- and P-band Synthetic Aperture Radar (SAR) backscatter. The SAR data were collected in the airborne BioSAR 2007 and BioSAR 2010 campaigns over the hemiboreal Remningstorp test site in southern Sweden. Regression models for biomass were developed using reference biomass maps created using airborne laser scanning data and field measurements. The results from regression analysis show that using HV backscatter (or VH) in a model with above-ground biomass and backscatter change on either natural logarithmic or square root, and decibel scale, respectively, explained most of the variation in the biomass change, both for L- and P-band. In the case of L-band, the two best cases showed R2 values of 66%, when comparing two SAR images acquired 2007 and 2010. For P-band using the same models, the best cases showed R2 values of 62%. In summary, the results look promising using L- and P-band backscattering for mapping biomass change.
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| 3. |
- Petersson, Erik, et al.
(författare)
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Effects of fin-clipping regarding adult return rates in hatchery-reared brown trout
- 2014
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 422-423, s. 249-252
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Tidskriftsartikel (refereegranskat)abstract
- Fin clipping has been used for decades as a marking method for sea-ranched salmonids but there are concerns about the method such as reduced survival and other animal welfare aspects. In this study sea migrating hatchery-reared brown trout juveniles (20-21 months old) were marked in four groups by removing either the adipose fin, left pelvic fin, both pelvic fins or the adipose fin + the left pelvic fin. All groups, together with an unmarked control group, were tagged with coded wire tags and released into the River Dalalven (Sweden). This was repeated over four years and on average the return rate was <1%. Brown trout marked by removing both pelvic fins had ca 30% lower adult return rate compared with the other four groups. The other three fin clipping groups did not differ from the unclipped control group. These results, in combination with earlier studies, indicate that adipose fin removal is least detrimental to the fish and removal of a single paired fin may be used in exceptional cases. We advise against multiple fin removal. (C) 2013 Elsevier B.V. All rights reserved.
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