Insect diversity boosted by combination of crop diversity and semi-
natural habitats

Date:
August 13, 2020
Source:
British Ecological Society
Summary:
To enhance the number of beneficial insect species in agricultural
land, preserving semi-natural habitats and promoting crop diversity
are both needed, according to new research.



FULL STORY ==========================================================================
To enhance the number of beneficial insect species in agricultural land, preserving semi-natural habitats and promoting crop diversity are both
needed, according to new research published in the British Ecological
Society's Journal of Applied of Ecology.


==========================================================================
The study, by researchers in Sweden, the UK, Italy, Germany, Spain and
France, found that increasing the diversity of crops in agricultural
landscapes increased the diversity of beneficial insects such as
pollinators. However, this benefit was only seen in landscapes with high proportions of semi-natural habitats such as forests and grassland.

In landscapes with both high crop diversity and semi-natural habitat
cover, the researchers observed an increased diversity of ground beetle
species as well as pollinators like bees and hoverflies. These insects
have the potential to benefit crops through predating pests or pollinating flowering crop plants, both important for crop yields.

The same effects were not found for spiders, which surprised the
researchers.

"We expected pollinators to benefit because they are a highly mobile
species, but the difference between ground beetles and spiders is
harder to explain since both share similar adaptations to inhabit local
crops." said Guillermo Aguilera of the Swedish University of Agricultural Sciences and lead author of the study.

Many beneficial insects and invertebrates are in decline, partly due
to intensive crop management practices and a loss of semi-natural
habitats from agriculture land, meaning the results have important implications. Guillermo Aguilera said: "We show that increasing local
insect communities is possible in landscapes with semi-natural habitats
by increasing crop diversity. Therefore, reducing the arable land and increasing semi-natural habitats is not always the only way for obtaining benefits from insects." Insects and other invertebrates provide important ecosystem services. "Ground beetles and spiders are predators of species
that can become pests. Wild pollinators have one of the most important
roles in flowering crops. Both services, pest control and pollination,
are important for the final crop yield." explains Guillermo Aguilera.

A greater diversity of crops may benefit pollinators through giving
them a more varied and continuous food source. Oilseed rape, the most
abundant flowering crop in the study area, provides massive resources
for pollinators. However, its flowers are only open for a short period
of time. Growing other crops that flower throughout the year could help
support pollinators.

Semi-natural habitats provide nesting sites and additional food for both pollinators and predators. They're likely to be particularly beneficial
to mobile species of ground beetles which often colonise crop fields
from these habitats.

The researchers compiled data from seven previous studies that looked at invertebrate abundances in crop fields. The data spanned 154 crop fields
in southern Sweden, an area consisting of arable land and semi-natural habitats, like grassland and woodland, between 2007 and 2017.

"The ultimate goal was to investigate the effect of crop diversity in
the landscape with local communities of invertebrates" said Guillermo
Aguilera.

"After obtaining the invertebrate information and the coordinates of
the fields where they were collected, we analysed the diversity of
crops present in the landscape at the time of the sampling as well as
the amount of semi-natural habitats such as grasslands." The research
focussed on southern Sweden, the most agriculturally important region in
the country in terms of crop production. While this gave the researchers
a large study area, they acknowledge that it's hard to generalise the
results to a more global landscape.

Guillermo Aguilera said "It would be interesting to see what happens in
other landscapes with a higher crop diversity by default than Sweden. It
would also be interesting to look at how invertebrate communities respond
to other forms of diversification in agriculture landscapes. For instance,
the management of certain crops is something that can vary a lot between countries or regions."

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


========================================================================== Journal Reference:
1. Guillermo Aguilera, Tomas Roslin, Kirsten Miller, Giovanni
Tamburini,
Klaus Birkhofer, Berta Caballero‐Lopez, Sandra
Ann‐Marie Lindstro"m, Erik O"ckinger, Maj Rundlo"f,
Adrien Rusch, Henrik G. Smith, Riccardo Bommarco. Crop diversity
benefits carabid and pollinator communities in landscapes with
semi‐natural habitats. Journal of Applied Ecology, 2020;
DOI: 10.1111/1365-2664.13712 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200813100642.htm

--- up 4 weeks, 1 day, 1 hour, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)