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Pollinating insect responses to grazing intensity, grassland characteristics and landscape complexity

behaviour, species diversity and composition

Sjödin, N. Erik (2007). Pollinating insect responses to grazing intensity, grassland characteristics and landscape complexity. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2007:55
ISBN 978-91-576-7354-1
[Doctoral thesis]

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Pollinators uphold important ecological functions and their economic and ecological importance is considerable. In the present thesis the relationship between management practices and the behaviour, diversity and composition of four flower visitor groups: bees, butterflies, hoverflies and beetles, are examined in grasslands with different grazing intensity and in different landscapes in East-Central Sweden. Four flower visitor groups were influenced by grazing intensity in different ways. Hoverflies and beetles were positively related to vegetation height, while bees and butterflies were not. In the latter two groups some species were favoured by short vegetation. Hoverflies were more species rich in forested landscapes, whereas butterfly species richness was lower in areas containing many roads. Bees showed the most complex responses mainly due to their diverse life-history strategies corresponding to different environmental factors. The species richness of nest-parasitic and soil nesting bees was favoured by intensive grazing and the existence of bare soil. Cylinder-nesting solitary bees were little affected by management, and high species richness was associated with eutrophication and low plant species richness. The reproductive output in this group can be measured by produced offspring biomass, and this related mainly to human activity. Bumblebees were influenced mainly by landscape factors and long-tongued species appearing late in the season were especially dependent on landscape connectivity and grassland cover. To maintain viable populations of flower visitors, alternative grazing strategies are recommended. To maintain a high diversity of flower visitors in isolated grasslands local optimisation of grazing may be the best strategy. In interconnected landscapes a better strategy may be to vary grazing intensity at the landscape level. Grasslands with different grazing management could thus complement each other. In landscapes where conditions are particularly good for specific insects, a third alternative would be to manage the landscape to enhance the diversity of this particular group.

Authors/Creators:Sjödin, N. Erik
Title:Pollinating insect responses to grazing intensity, grassland characteristics and landscape complexity
Subtitle:behaviour, species diversity and composition
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2007
Number of Pages:39
ALLI. Sjödin, N. E. Pollinator behavioural responses to grazing intensity. Biodiversity and conservation DOI, 10.1007/s10531-006-9103-0. II. Sjödin, N E. Bengtsson & J. Ekbom, B. The influence of grazing intensity and landscape composition on pollinator diversity. (Submitted manuscript). III. Sjödin, N E. Ekbom, B. & Bengtsson, J. Bee (Apoidea) guild variability in semi-natural grasslands. (Submitted manuscript). IV. Sjödin, N E. Reproductive success in trap-nesting bees found in seminatural grasslands. (Manuscript).
Place of Publication:Uppsala
ISBN for printed version:978-91-576-7354-1
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:apidae, syrphidae, lepidoptera, coleoptera, pollinators, life cycle, behaviour, grasslands, natural pastures, grazing intensity, biodiversity, landscape, ecology, sweden
Keywords:Semi-natural grasslands, grazing intensity, behaviour, diversity, Apoidea, Syrphidae, Lepidoptera, Coleoptera, landscape ecology, life-history traits
Permanent URL:
ID Code:1388
Department:(NL, NJ) > Dept. of Ecology
(S) > Dept. of Ecology
Deposited By: N Erik Sjödin
Deposited On:13 Apr 2007 00:00
Metadata Last Modified:02 Dec 2014 10:11

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