Worldwide Insect Decline
Above: Painted Lady butterfly Vanessa cardui on Zinnia.A paper has been published, which highlights the worrying worldwide decline of insects.
The
paper, Worldwide decline of the entomofauna: A review of its drivers (1) by Francisco
Sánchez-Bayo and Kris A.G. Wyckhuys, presents a thorough review of 73
historical reports of insect declines from across the globe, and systematically
assesses the underlying drivers.
Key
Points From The Paper
- Over 40% of insect species are threatened with extinction.
- Lepidoptera (moths and butterflies), Hymenoptera (bees, wasps, ants and sawflies) and dung beetles (Coleoptera) are the taxa most affected.
- Four
aquatic taxa are dangerously threatened, and have already lost a large
proportion of species.
- Affected insect groups include both specialists that occupy particular ecological niches, as well as many common and generalist species.
Are
Any Insect Species Increasing?
The
abundance of a small number of species is increasing. These are adaptable, generalist species that
are occupying the vacant niches left by the ones declining.
Drivers
Of Insect Decline
The
main drivers of species declines listed in order of importance:
These drivers are of course, well known and established, but action needs to be taken to make a meaningful difference as quickly as possible. |
Solution
The paper proposes:
“A rethinking of current agricultural practices, in particular a
serious reduction in pesticide usage and its substitution with more
sustainable, ecologically-based practices, is urgently needed to slow or
reverse current trends, allow the recovery of declining insect populations and
safeguard the vital ecosystem services they provide. In addition, effective remediation
technologies should be applied to clean polluted waters in both agricultural
and urban environments.”
Comment
– The Impact On Birds
In
tandem with global insect decline, birds have also been declining, especially those of
farmland habitats. The increased use
and efficacy of pesticides leads to the loss of insect food and wildflower
and weed seeds. Many small farmland
birds feed their young chicks on insects in the spring and summer months, whilst the
developed adults eat mainly seeds.
In
2013, Bird Life International wrote:
“An
analysis of 148 of Europe’s common birds has revealed that, over a 30-year
period, 57 species (39%) have declined across 25 European countries. Farmland birds have fared particularly badly,
with 300 million fewer birds today than in 1980. These population trends of representative
suites of wild birds can indicate the health of the environment, for birds and
wider biodiversity.”
“A
comparison of new and old EU Member States shows that although farmland birds
were performing better in new EU countries, their trends appear to be worsening
in recent years, now mimicking the trends in old EU countries. It is widely
accepted that these declines have been driven by agricultural intensification
and the resulting deterioration of farmland habitats, and it is likely that the
trends observed are mirrored by other farmland taxa.” (2)
They also state:
- An assessment in 1994 estimated that 25% of all European bird species were undergoing substantial population declines (Tucker and Heath 1994).
- Overall, out of 148 bird species, 57 (39%) have declined over 30 years, from 1980 to 2010.
References
(1) Worldwide decline of the entomofauna: A review of its drivers.
(2) Europe-wide monitoring schemes highlight declines in widespread farmland birds.
COPYRIGHT 2010 - 2019: WWW.BUZZABOUTBEES.NET
ALL RIGHTS RESERVED.
