Warming climate and agriculture halve insect populations in some areas


Date:
April 20, 2022
Source:
University College London
Summary:
Climate change and intensive agricultural land use have already
been responsible for a 49% reduction in the number of insects in
the most impacted parts of the world, finds a new study.



FULL STORY ========================================================================== Climate change and intensive agricultural land use have already been responsible for a 49% reduction in the number of insects in the most
impacted parts of the world, finds a new study by UCL researchers.


==========================================================================
The study published in Nature is the first to identify that an interaction between rising temperatures and land use changes, is driving widespread
losses in numerous insect groups across the globe.

Lead author Dr Charlie Outhwaite (UCL Centre for Biodiversity &
Environment Research, UCL Biosciences) said: "Many insects appear to be
very vulnerable to human pressures, which is concerning as climate change worsens and agricultural areas continue to expand. Our findings highlight
the urgency of actions to preserve natural habitats, slow the expansion of high-intensity agriculture, and cut emissions to mitigate climate change.

"Losing insect populations could be harmful not only to the natural environment, where insects often play key roles in local ecosystems,
but it could also harm human health and food security, particularly with
losses of pollinators.

"Our findings may only represent the tip of the iceberg as there is
limited evidence in some areas, particularly in the tropics which we
found have quite high reductions in insect biodiversity in the most
impacted areas." The researchers analysed a large dataset of insect
abundance and species richness from areas across the globe, including three-quarters of a million records for nearly 20,000 insect species.



==========================================================================
The team compared insect biodiversity in different areas depending on
how intensive agriculture is in the area, as well as how much historic
climate warming the local area has experienced.

They found that in areas with high-intensity agriculture and substantial climate warming, the number of insects was 49% lower than in the most
natural habitats with no recorded climate warming, while the number of different species was 29% lower. Tropical areas saw the biggest declines
in insect biodiversity linked to land use and climate change.

The researchers found that in areas of low-intensity agriculture and substantial climate warming, having nearby natural habitat buffered the
losses: where 75% of the land was covered by natural habitat, insect
abundance only declined by 7%, compared to a 63% reduction in comparable
areas with only 25% natural habitat cover. Many insects rely on plants
for shade on hot days, so a loss of natural habitats could leave them
more vulnerable to a warming climate.

The researchers say that insect declines due to human influences may
be even greater than their findings suggest as many areas with long
histories of human impacts would have already seen biodiversity losses
before the start of the study period, and the study also did not account
for the effects of other drivers such as pollution.

Senior author Dr Tim Newbold (UCL Centre for Biodiversity & Environment Research) said: "The environmental harms of high-intensity agriculture
present a tricky challenge as we try to keep up with food demands of
a growing population. We have previously found that insect pollinators
are particularly vulnerable to agricultural expansion, as they appear to
be more than 70% less abundant in high-intensity croplands compared to
wild sites. Careful management of agricultural areas, such as preserving natural habitats near farmland, may help to ensure that vital insects
can still thrive." Joint first author Peter McCann, who conducted the
research while completing an MSc at the UCL Centre for Biodiversity & Environment Research, said: "We need to acknowledge how important insects
are for the environment as a whole, and for human health and wellbeing,
in order to address the threats we pose to them before many species
are lost forever." UCL Centre for Biodiversity & Environment Research scientists are at the forefront of research into human impacts on the
planet, such as by developing the science underpinning the IUCN's Red
List that quantifies extinction risk, and discovering that changes to
land use may be increasing the risks of disease outbreaks like Covid-19
that jump from animals to humans. The centre's new interdisciplinary
People and Nature Lab is developing innovative approaches, such as
citizen science programmes and employing artificial intelligence, to
tackle these urgent global challenges and foster a more sustainable relationship between people and nature.

The research was supported by the Natural Environment Research Council
and the Royal Society.


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


========================================================================== Journal Reference:
1. Charlotte L. Outhwaite, Peter McCann, Tim Newbold. Agriculture and
climate change are reshaping insect biodiversity worldwide. Nature,
2022; DOI: 10.1038/s41586-022-04644-x ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220420112914.htm

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