Biodiversity: Land use - Threat to and opportunity for bumblebees

Date:
August 20, 2021
Source:
Karlsruher Institut fu"r Technologie (KIT)
Summary:
Bumblebees largely contribute to the pollination of crops. However,
they are threatened by land use changes due to climate
change. Long-term simulations have now shown that smart land
management may stabilize some species.



FULL STORY ========================================================================== Bumblebees largely contribute to the pollination of crops. However,
they are threatened by land use changes due to climate change. Long-term simulations made by researchers of Karlsruhe Institute of Technology (KIT)
and partners from Italy have now shown that smart land management may
stabilize some species. The results are reported in Global Change Biology.


==========================================================================
The global food system depends strongly on pollination by
insects. According to the European Commission, this ecosystem service can
be estimated to be worth several billion euros for Europe alone. Wild pollinators, such as bumblebees, play an important role. But their
dispersion areas will change as a result of climate change. "Earlier
studies revealed that populations of more than half of the European
bumblebee species are decreasing," says Dr. Reinhard Prestele from
the Atmospheric Environmental Research Department of the Institute
of Meteorology and Climate Research (IMK-IFU), KIT'S Campus Alpine
in Garmisch- Partenkirchen. "But bumblebee populations are not only
threatened by climate, also by land use changes." Although the risks of intensive agriculture are known, they were not differentiated sufficiently
from climate change in continental studies. This has now been done by researchers of KIT and partners from the Joint Research Centre (JRC)
of the European Commission in Ispra (Italy). They simulated the effects
of land use changes on the future dispersion of European bumblebees.

Models Reveal Potential Development Paths For their study, the researchers calculated potential dispersions of 47 European bumblebee species for
the years 2050 and 2080 in seven scenarios based on various assumptions relating to future climate and land use changes in Europe. "We compared projections for a constant climate and dynamic land use with projections
for the opposite case," Penelope Whitehorn (IMK-IFU) says.

"Climate changes turned out to have the strongest total effect and to
threaten the existence of many bumblebee species. In some scenarios,
however, some rare species are affected by land use changes as severely
as they are by climate change." Apart from the loss of their habitat,
excessive use of fertilizers and pesticides plays a role." In this
connection, other studies already revealed that colonies grow more slowly
and produce less queens," Whitehorn adds.

Protection by Smart Land Management But simulations also show that there
is a glimmer of hope for threatened bumblebee species. Determined
climate protection combined with smart land management, such
as increased organic farming and protected refuge areas for the
species, may help stabilize some species even under moderate climate
change. Development of the corresponding protection strategies,
however, still requires research, Prestele says. "For concrete
findings as to what may help, we still need better models of specific ecological processes, such as the role of small habitats in agricultural regions and the precise impacts of different land use methods on the
life cycle of bumblebee colonies." Long-term simulations of land
use changes will not only allow to derive protection measures for
bumblebees. "Our approach may also be transferred to other important
wild pollinators, like wild bees and wasps," Prestele adds. (mhe) ========================================================================== Story Source: Materials provided by
Karlsruher_Institut_fu"r_Technologie_(KIT). Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Reinhard Prestele, Calum Brown, Chiara Polce, Joachim Maes, Penelope
Whitehorn. Large variability in response to projected climate and
land‐use changes among European bumblebee species. Global
Change Biology, 2021; DOI: 10.1111/gcb.15780 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210820111112.htm

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