Wild bees depend on the landscape structure
Research team investigates flower strips, organic farming and small crop fields

Date:
June 30, 2020
Source:
University of Go"ttingen
Summary:
Sowing strips of wildflowers along conventional cereal fields
and the increased density of flowers in organic farming encourage
bumblebees as well as solitary wild bees and hoverflies. Bumblebee
colonies benefit from flower strips along small fields, but in
organic farming, they benefit from large fields.



FULL STORY ========================================================================== Sowing strips of wildflowers along conventional cereal fields and the
increased density of flowers in organic farming encourage bumblebees as
well as solitary wild bees and hoverflies. Bumblebee colonies benefit from flower strips along small fields, but in organic farming, they benefit
from large fields. This research was carried out by agroecologists from
the University of Go"ttingen in a comparison of different farming systems
and landscape types. The results of the study have been published in
the Journal of Applied Ecology.


========================================================================== Organic farming and flower strips are financially supported by
the European Union in order to enhance populations of wild bees
and hoverflies, which are major pollinators of most crops and wild
plants. The research team selected nine landscapes in the vicinity of Go"ttingen along a gradient of increasing field size and then analysed
the wild bees and hoverflies in each landscape at the edge of an organic
wheat field, in a flower strip along conventional wheat, and at the
edge of a conventional wheat field without flower strips. The result:
most pollinators were found in the flower strips, but organic fields, characterized by more flowering wild plants than conventional fields,
were also beneficial. Bumblebee colonies established on the margins
of fields as part of the project produced more queens in flower strips
when located in landscapes with small conventional fields. In contrast,
large areas were particularly advantageous when it came to flower-rich
organic fields. Flower strips offer a high local density of pollen and
nectar, but organic areas compensate for this by their increased area.

"The results show that action at both local and landscape level is
important to promote wild bees," emphasises Costanza Geppert, first author
of the study. The investigations were part of her Master's thesis in the Agroecology Group in the Department of Crop Sciences at the University
of Go"ttingen. "Wild bees and other insects cannot survive in a field
simply by making improvements to that field, they depend on the structure
of the surrounding landscape," adds Head of Department Professor Teja Tscharntke. "Therefore, future agri-environmental schemes should take
more account of the overall landscape structure," adds Dr Pe'ter Bata'ry
who initiated the study.


========================================================================== Story Source: Materials provided by University_of_Go"ttingen. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Costanza Geppert, Annika Hass, Rita Fo"ldesi, Bettina Donko',
Asma Akter,
Teja Tscharntke, Pe'ter Bata'ry. Agri‐environment schemes
enhance pollinator richness and abundance but bumblebee reproduction
depends on field size. Journal of Applied Ecology, 2020; DOI:
10.1111/1365- 2664.13682 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200630125142.htm

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