Pollination, seed set and seed predation on a landscape scale

Citation
I. Steffan-dewenter et al., Pollination, seed set and seed predation on a landscape scale, P ROY SOC B, 268(1477), 2001, pp. 1685-1690
Citations number
49
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Experimental Biology
Journal title
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES
ISSN journal
0962-8452 → ACNP
Volume
268
Issue
1477
Year of publication
2001
Pages
1685 - 1690
Database
ISI
SICI code
0962-8452(20010822)268:1477<1685:PSSASP>2.0.ZU;2-C
Abstract
We analysed the combined effects of pollination and seed predation on seed set of Centaurea jacea in 15 landscapes differing in structural complexity. In the centre of each landscape, a patch of Centaurea plants was establish ed for standardized measurements of flower visitation, seed predation and s eed set. Both the number of flower-visiting bees and the proportion of flow er heads damaged by seed predators increased,,vith landscape complexity, wh ich was measured as the proportion of semi-natural habitats. The mean numbe r of seeds per flower head did not increase with the proportion of semi-nat ural habitats, presumably because of the counterbalancing effects of pollin ation and seed predation. For a subset of undamaged flower heads, the numbe r of seeds per flower head was positively correlated with the number of flo wer visits. Further reasons for the unexpected failure to detect a correlat ion between landscape complexity and seed set appeared to be changes in flo wer-visitor behaviour and the contrasting responses of honeybees and wild b ees to habitat context. Landscape analyses at eight spatial scales (radius of landscape sectors, 250-3000 m) showed that different groups perceived th e landscape at different spatial scales. Changes in pollinator numbers coul d be explained only at small scales (up to 1000 m), while the seed predator s also responded to large scales (up to 2500 m).