Journal of Environmental Biology

The wild flora biodiversity in pesticide free bufferzones along old hedgerows

Author Details

L.C. Andresen

(Corresponding author)

Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen,

Denmark

Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Sciencepark 904,

1098 XH Amsterdam, Netherlands

e-mail: l.c.andresen@uva.nl

J. Nothlev

Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen,

Denmark

K. Kristensen

Department of Genetics and Biotechnology, University of Aarhus, Blichers All? 20, DK-8830 Tjele,

Denmark

S. Navntoft

Department of Agriculture and Ecology, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark

I. Johnsen

Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark

Publication Data

Paper received:

14 September 2010

Revised received:

17 February 2011

Re-revised received:

02 May 2011

Accepted:

25 May 2011

Abstract

The natural field margin ecotone from the field border and into a cropped field hosts a diversity of plant species. In conventional cropped fields, biodiversity suffers from fertilizer and pesticide application.? In our study at Danish conventional spring-barley fields, we laid out bufferzones with no pesticide application spraying after sowing, with the widths: 24, 12, 6 and 4 m (and control) to the field edge hedgerow. Through one season: plant species number, biodiversity and evenness for each bufferzone at the distances: 18, 9, 5, 2 and 0 m from the hedgerow were significantly affected by distance to the hedge and by width of bufferzone.? The bufferzones affected: species number (total of 92 weed species), species diversity (1.27 to 0.44) and species evenness index (0.63 to 0.87), and revealed that the bufferzone of 24 m gave the largest improvement of the field margin for plants. Decreasing the bufferzone widths provided smaller biodiversity and larger evenness of plants at distances larger than the buffer width: the distance at which diversity (Shannons) was reduced by half the difference between hedge- and field diversity was 1.2, 3.1, 6.7, 10.8 and 10.9 m in bufferwidth treatments of 0, 4, 6, 12 and 24 m; likewise, the half-way distance for Smiths and Wilsons evenness index was 1.2, 1.7, 5.4, 14.0 and 30.2 m in the bufferwidth treatments of 0, 4, 6, 12 and 24 m.? Based on modelled diversity and evenness indexes a positive effect of buffer was evident from 6 m bufferzone. The average diversity over the distances from 0 to 18 m was 0.66, 0.75, 0.98, 1.14 and 1.11 in bufferwidth treatments of 0, 4, 6, 12 and 24 m and the average evenness over the distances from 0 to 18 m was 0.82, 0.80, 0.74, 0.66 and 0.63, in bufferwidth treatments of 0, 4, 6, 12 and 24 m. Furthermore, the accumulated number of species revealed that a bufferzone width of at least 6 m was needed to significantly increase the species richness at all distances between 2 and 18 m. At 18 m distance, the accumulated number of species was 37.1, 39.7, 41.2, 42.4 and 42.7 in bufferwidth treatments of 0, 4, 6, 12 and 24 m. ??

Key words

Bufferstrips, Field margin management, Hedge, Herbicide, Insecticide?

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