Local and landscape effects of organic farming on butterfly species richness and abundance
Författare
Summary, in English
1. Agri-environmental schemes (AES) are commonly adopted in Europe to reduce the loss of farmland biodiversity. These schemes have, however, been criticized as not fulfilling this goal, partly because their effectiveness is thought to differ depending on external factors such as landscape heterogeneity, the focal organism and scale of application.
2. We used one AES, organic farming, as a landscape-scale experiment to test whether its effect on butterflies depends on the spatial scale at which it is applied. Our study system consisted of organically and conventionally managed fields within eight pairs of matched landscapes, differing in the proportion of land under organic management at the landscape scale. Butterflies and their nectar and host-plant resources were surveyed along the fields and adjacent field borders.
3. Butterfly species richness and abundance were significantly increased by organic farming at the
local scale. However, local butterfly species richness was also positively affected by a large proportion
of organic farming in the surrounding landscape, independent of the local farming practice. Local and landscape farming practices interacted such that the farming practice within fields had a larger
effect on butterfly abundance if surrounded by conventionally rather than organically managed fields. These results could only partly be explained by variation in local availability of nectar and host-plant resources.
4. The total observed species richness (γ-diversity) was higher in organically managed landscapes, mainly because of higher within-field diversity (α-diversity), whereas the between-field diversity (β-diversity) tended to be similar in both landscape types.
5. Synthesis and applications. Butterflies were positively affected by organic farming at a local scale,
but the amount of organic farming in the surrounding landscape had either an additive (species richness) or interactive (abundance) effect. Therefore, the spatial distribution of AES must be taken into account to maximize their potential to increase farmland biodiversity. We have shown that organic farming affected butterfly species richness on nearby conventionally managed land. This suggests a landscape effect of organic farming that may indicate a wider benefit of AES for biodiversity
conservation.
2. We used one AES, organic farming, as a landscape-scale experiment to test whether its effect on butterflies depends on the spatial scale at which it is applied. Our study system consisted of organically and conventionally managed fields within eight pairs of matched landscapes, differing in the proportion of land under organic management at the landscape scale. Butterflies and their nectar and host-plant resources were surveyed along the fields and adjacent field borders.
3. Butterfly species richness and abundance were significantly increased by organic farming at the
local scale. However, local butterfly species richness was also positively affected by a large proportion
of organic farming in the surrounding landscape, independent of the local farming practice. Local and landscape farming practices interacted such that the farming practice within fields had a larger
effect on butterfly abundance if surrounded by conventionally rather than organically managed fields. These results could only partly be explained by variation in local availability of nectar and host-plant resources.
4. The total observed species richness (γ-diversity) was higher in organically managed landscapes, mainly because of higher within-field diversity (α-diversity), whereas the between-field diversity (β-diversity) tended to be similar in both landscape types.
5. Synthesis and applications. Butterflies were positively affected by organic farming at a local scale,
but the amount of organic farming in the surrounding landscape had either an additive (species richness) or interactive (abundance) effect. Therefore, the spatial distribution of AES must be taken into account to maximize their potential to increase farmland biodiversity. We have shown that organic farming affected butterfly species richness on nearby conventionally managed land. This suggests a landscape effect of organic farming that may indicate a wider benefit of AES for biodiversity
conservation.
Publiceringsår
2008
Språk
Engelska
Sidor
813-820
Publikation/Tidskrift/Serie
Journal of Applied Ecology
Volym
45
Issue
3
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
John Wiley & Sons Inc.
Ämne
- Ecology
Nyckelord
- agri-environment schemes
- diversity
- conservation
- farming practice
- Lepidoptera
- landscape ecology
- spatial distribution
- additive partitioning
- spatial scales
Status
Published
Forskningsgrupp
- Biodiversity and Conservation Science
ISBN/ISSN/Övrigt
- ISSN: 1365-2664