Semi-natural habitat patches complement flower strips in protecting pollinators

Date:
August 3, 2021
Source:
University of Freiburg
Summary:
Ecologists observe the diversity of insects on the edge of apple
orchards on Lake Constance.



FULL STORY ==========================================================================
At the moment, many flower strips are buzzing and humming: cornflowers, poppies, wild carrots and many other flowers attract numerous insects. The field edges covered by these flowers typically bloom between mid-May and
mid- August. Complementary habitats are needed to support pollinator
insects in agricultural landscapes throughout the year. Semi-natural
small structures, such as ditches, banks, hedgerows, or overgrown fences,
could provide such a complement. "Researchers have already shown many
times how important natural habitats are for pollinators. Almost always, however, only large-scale structures have been researched for this
purpose, for example, wide meadows or pastures. Studies on what small structures mean for pollinators and which species particularly benefit
from them are rare," says Vivien von Ko"nigslo"w from the Institute of
Earth and Environmental Sciences at the University of Freiburg. As a
result, together with Dr. Anne-Christine Mupepele and Prof. Dr.

Alexandra-Maria Klein, she studied flower strips as well as semi-natural habitat patches in the Lake Constance area over a period of two years,
a place in which there is a particular interest in pollinating insects
due to large- scale fruit cultivation. The researchers published their
results in the journal Biological Conservation.


========================================================================== Semi-natural habitats attract more bees "Our goal was to find out
how the diversity of wild bees and hoverflies can be promoted in the
vicinity of large-scale orchards," says von Ko"nigslo"w. To do this,
their study compared the occurrence of bees and hoverflies in flower
strips and in existing flower-rich habitats, each located on the edge of conventional apple orchards in southern Germany. Their analysis showed
that the different flowering times and plant species in the semi-natural habitats, such as hedgerows and small groves, mainly benefit solitary and oligolectic bees, i.e. those that collect only one pollen species. The
existing biotope areas attracted bee species with a different pollen specialization than the sown flower strips. At the same time, the
researchers found a greater number of pollinators in the flower strips
and counted more species than in the small structures. "Thus, semi-natural habitats complement existing flower strips," von Ko"nigslo"w concludes.

For their research, the ecologists established flower strips at the edge
of private orchards in 2018. Semi-natural small structures, including
drainage ditches, embankments and overgrown fences, were already in
place. The researchers monitored the bees and hoverflies at least once
a month from spring to late summer.

Effective and cost-efficient "Semi-natural habitat patches can play
an important role in protecting pollinators because they help ensure
that flowers are available all year round," says Klein, head of the
Chair of Nature Conservation and Landscape Ecology at the University
of Freiburg. They also provide potential retreats and nesting sites,
which are important for overwintering bumblebees, for example.

"For effective and cost-efficient protection of pollinating insects, the
focus should not only be on flower strips," Klein concludes. "Existing
small structures of spontaneous vegetation, plant species that grow
on their own from existing seeds in the soil, are also attractive to
insects and should be preserved." The Freiburg scientist explains that
at present, however, there are hardly any incentives for farmers to
develop and preserve small semi-natural habitat patches.

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


========================================================================== Journal Reference:
1. Vivien von Ko"nigslo"w, Anne-Christine Mupepele, Alexandra-Maria
Klein.

Overlooked jewels: Existing habitat patches complement sown flower
strips to conserve pollinators. Biological Conservation, 2021;
261: 109263 DOI: 10.1016/j.biocon.2021.109263 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210803121337.htm

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