ArticlePDF Available
correspondence
International scientists formulate a roadmap for
insect conservation and recovery
To the Editor — A growing number of
studies are providing evidence that a suite
of anthropogenic stressors — habitat loss
and fragmentation, pollution, invasive
species, climate change and overharvesting
— are seriously reducing insect and other
invertebrate abundance, diversity and
biomass across the biosphere18. These
declines affect all functional groups:
herbivores, detritivores, parasitoids,
predators and pollinators. Insects are
vitally important in a wide range of
ecosystem services9 of which some are
vitally important for food production and
security (for example, pollination and
pest control)10. There is now a strong
scientific consensus that the decline of
insects, other arthropods and biodiversity
as a whole, is a very real and serious threat
that society must urgently address1113. In
response to the increasing public awareness
of the problem, the German government is
committing funds to combat and reverse
declining insect numbers13. This funding
should act as a clarion call to other
nations across the world — especially
wealthier ones — to follow suit and
to respond proactively to the crisis by
addressing the known and suspected threats
and implementing solutions.
We hereby propose a global ‘roadmap’
for insect conservation and recovery
(Fig. 1). This entails the immediate
implementation of several ‘no-regret’
measures (Fig. 1, step 1) that will act
to slow or stop insect declines. Among the
initiatives we encourage are the following
immediate measures:
Taking aggressive steps to reduce
greenhouse gas emissions; reversing recent
trends in agricultural intensification
including reduced application of synthetic
pesticides and fertilizers and pursuing
their replacement with agro-ecological
measures; promoting the diversification
and maintenance of locally adapted land-
use techniques; increasing landscape
heterogeneity through the maintenance of
natural areas within the landscape matrix
and ensuring the retention and creation of
microhabitats within habitats which may be
increasingly important for insects during
extreme climatic events such as droughts or
heatwaves; reducing identified local threats
such as light, water or noise pollution,
invasive species and so on; prioritizing the
import of goods that are not produced at
the cost of healthy, species-rich ecosystems;
designing and deploying policies (for
example, subsidies and taxation) to induce
the innovation and adoption of insect-
friendly technologies; enforcing stricter
measures to reduce the introduction of alien
species, and prioritizing nature-based tactics
for their (long-term) mitigation; compiling
and implementing conservation strategies
for species that are vulnerable, threatened
or endangered; funding educational
and outreach programs, including those
tailored to the needs of the wider public,
farmers, land managers, decision makers
and conservation professionals; enhancing
citizen science’ or ‘community science’
as a way of obtaining more data on insect
diversity and abundance as well as engaging
the public, especially in areas where
academic or professional infrastructure is
lacking; devising and deploying measures
across agricultural and food value chains
that favour insect-friendly farming,
including tracking, labelling, certification
and insurance schemes or outcome-based
incentives that facilitate behavioural
changes, and investing in capacity building
to create a new generation of insect
conservationists and providing knowledge
and skills to existing professionals
(particularly in developing countries).
To better understand changes in insect
abundance and diversity, research should
aim to prioritize the following areas:
Quantifying temporal trends in insect
abundance, diversity and biomass by
extracting long-term datasets from existing
insect collections to inform new censuses;
exploring the relative contributions
of different anthropogenic stressors
causing insect declines within and across
different taxa; initiating long-term studies
comparing insect abundance and diversity
in different habitats and ecosystems along
a management-intensity gradient and at
the intersection of agricultural and natural
habitats; designing and validating insect-
friendly techniques that are effective,
locally relevant and economically sound in
agriculture, managed habitats and urban
environments; promoting and applying
standardized monitoring protocols globally
and establishing long-term monitoring plots
or sites based on such protocols, as well as
increasing support for existing monitoring
efforts; establishing an international
governing body under the auspices of
existing bodies (for example, the United
Nations Environment Programme (UNEP)
or the International Union for Conservation
of Nature (IUCN)) that is accountable for
documenting and monitoring the effects of
proposed solutions on insect biodiversity in
the longer term; launching public–private
partnerships and sustainable financing
initiatives with the aim of restoring,
protecting and creating new vital insect
habitats as well as managing key threats;
increasing exploration and research to
improve biodiversity assessments, with
a focus on regional capacity building in
understudied and neglected areas, and
performing large-scale assessments of the
conservation status of insect groups to help
define priority species, areas and issues.
Most importantly, we should not wait
to act until we have addressed every key
knowledge gap. We currently have enough
information on some key causes of insect
decline to formulate no-regret solutions
whilst more data are compiled for lesser-
known taxa and regions and long-term data
are aggregated and assessed. Implementation
should be accompanied by research that
examines impacts, the results of which
can be used to modify and improve the
implementation of effective measures.
Furthermore, such a ‘learning-by-doing’
approach ensures that these conservation
strategies are robust to newly emerging
pressures and threats. We must act now.
Jerey A. Harvey  1*,
Robin Heinen  1, Inge Armbrecht  2,
Yves Basset3, James H. Baxter-Gilbert4,
T. Martijn Bezemer  1, Monika Böhm  5,
Riccardo Bommarco  6,
Paulo A. V. Borges  7, Pedro Cardoso8,
Viola Clausnitzer9, Tara Cornelisse10,
Elizabeth E. Crone11, Marcel Dicke  12,
Klaas-Douwe B. Dijkstra13, Lee Dyer14,
Jacintha Ellers  15, Thomas Fartmann16,
Mathew L. Forister14, Michael J. Furlong17,
Andres Garcia-Aguayo18, Justin Gerlach19,
Rieta Gols  12, Dave Goulson  20,
Jan-Christian Habel21, Nick M. Haddad  22,
Caspar A. Hallmann23, Sérgio Henriques  5,
Marie E. Herberstein24, Axel Hochkirch25,
Alice C. Hughes26, Sarina Jepsen27,
T. Hefin Jones28, Bora M. Kaydan29,
David Kleijn30, Alexandra-Maria Klein  31,
NATURE ECOLOGY & EVOLUTION | www.nature.com/natecolevol
correspondence
Tanya Latty32, Simon R. Leather  33,
Sara M. Lewis11, Bradford C. Lister34,
John E. Losey35, Elizabeth C. Lowe24,
Craig R. Macadam  36,
James Montoya-Lerma37,
Christopher D. Nagano10, Sophie Ogan25,
Michael C. Orr  38, Christina J. Painting39,
Thai-Hong Pham40, Simon G. Potts41,
Aunu Rauf42, Tomas L. Roslin6,
Michael J. Samways43,
Francisco Sanchez-Bayo44, Sim A. Sar45,
Cheryl B. Schultz  46, António O. Soares  7,
Anchana Thancharoen47, Teja Tscharntke48,
Jason M. Tylianakis  49,
Kate D. L. Umbers  50, Louise E. M. Vet1,
Marcel E. Visser  1, Ante Vujic51,
David L. Wagner52,
Michiel F. WallisDeVries  53,
1. No-regret solutions
3. New research
Solution
Avoid and mitigate
alien species
introductions
Phase out
pesticide use,
and replace
with ecological
measures
Enhance
restoration and
conservation
programs
Increase
landscape
heterogeneity
in agriculture
Phase out
pesticide use,
and replace
with ecological
measures
Increase
landscape
heterogeneity
in agriculture
Phase out
pesticide use,
and replace
with ecological
measures
Education for
awareness, citizen
science and capacity
building
Conservation
of threatened
species
Reduce light,
water and
noise pollution
Reduce imports
of ecologically
harmful products
2. Prioritization
Perform large-scale assessments
of the conservation status of insect
groups to define priority species,
areas and issues, for example increase
the number of insects with informative
IUCN Red List assessments.
Immediate action
Mid-term action
Conduct new research to disentangle the
contributions of different anthropogenic
stressors driving insect declines, within
and across different taxa. Perform field
studies along a management-intensity
gradient and at the intersects of agricultural
and natural habitats. Increase explorative
research to accelerate rate of knowledge
gain in understudied areas.
5. Partnerships
Long-term action
Launch public–private partnerships and
sustainable financing initiatives with the
aim of restoring, protecting and creating
new vital insect habitats, as well as
managing key threats.
4. Existing data
Analyse current data on insect diversity that
is present, such as in private, museum and
academic insect collections. This is important
to form new censuses of past insect diversity.
This is especially important in areas where
scientific data currently do not exist.
6. Global monitoring program
Promote and apply standardized monitoring
protocols at a global level under the auspices
of an existing international governing body
(for example, the UN or IUCN). Establish
standardized sites where monitoring is
conducted over longer terms. Ensure support
for existing monitoring efforts.
Fig. 1 | Roadmap to insect conservation and recovery, calling for action at short-, intermediate- and long-term timescales. No-regret measures for immediate
utilization in insect conservation refer to actions that should be implemented as soon as possible. These solutions will be beneficial to society and biodiversity
even if the direct effects on insects are not known as of yet (that is, no-regret solutions). This encompasses utilization of insect-friendly techniques that are
effective, locally relevant and economically sound, for example, in farming, habitat management and urban development.
NATURE ECOLOGY & EVOLUTION | www.nature.com/natecolevol
correspondence
Catrin Westphal54, Thomas E. White  32,
Vicky L. Wilkins55, Paul H. Williams56,
Kris A. G. Wyckhuys  57, Zeng-Rong Zhu58
and Hans de Kroon23
1Netherlands Institute of Ecology (NIOO-KNAW),
Wageningen, e Netherlands. 2Departamento de
Biología, Universidad del Valle, Cali, Colombia.
3ForestGEO, Smithsonian Tropical Research Institute,
Panama City, Panama. 4Centre for Invasion
Biology, Stellenbosch University, Matieland, South
Africa. 5Institute of Zoology, Zoological Society of
London, London, UK. 6Department of Ecology,
Swedish University of Agricultural Sciences,
Uppsala, Sweden. 7cE3c-Centre for Ecology,
Evolution and Environmental Changes / Azorean
Biodiversity Group, University of Azores, Lisbon,
Portugal. 8Laboratory for Integrative Biodiversity
Research (LIBRe), Finnish Museum of Natural
History, University of Helsinki, Helsinki, Finland.
9Senckenberg Research Institute, Goerlitz, Germany.
10Center for Biological Diversity, Portland, OR, USA.
11Department of Biology, Tus University, Medford,
MA, USA. 12Laboratory of Entomology, Wageningen
University, Wageningen, e Netherlands. 13IUCN
SSC Freshwater Conservation Committee, Naturalis
Biodiversity Center, Leiden, e Netherlands.
14Biology Department, University of Nevada, Reno,
NV, USA. 15Department of Ecological Sciences,
Vrije University, Amsterdam, e Netherlands.
16Department of Biodiversity and Landscape Ecology,
Osnabrück University, Osnabrück, Germany. 17School
of Biological Sciences, e University of Queensland,
St Lucia, Queensland, Australia. 18Estacion de
Biología Chamela, Instituto de Biología, Chamela,
Jalisco, Mexico. 19IUCN SSC Terrestrial Invertebrate
Red List Authority, Cambridge, UK. 20School of
Life Sciences, University of Sussex, Brighton, UK.
21Evolutionary Zoology, Department of Biosciences,
University of Salzburg, Salzburg, Austria. 22Kellogg
Biological Station and Department of Integrative
Biology, Michigan State University, Hickory Corners,
MI, USA. 23Institute for Water and Wetland Research,
Radboud University, Nijmegen, e Netherlands.
24Department of Biological Sciences, Macquarie
University, Sydney, New South Wales, Australia.
25Department of Biogeography, Trier University, Trier,
Germany. 26Centre for Integrative Conservation,
Xishuangbanna Tropical Botanical Garden, Chinese
Academy of Sciences, Menglun, Yunnan, China.
27e Xerces Society for Invertebrate Conservation,
Portland, OR, USA. 28School of Biosciences, Cardi
University, Cardi, UK. 29Biotechnology Application
and Research Centre, Çukurova University, Balcalı,
Adana, Turkey. 30Plant Ecology and Nature
Conservation Group, Wageningen University,
Wageningen, e Netherlands. 31Albert Ludwigs
University of Freiburg, Freiburg, Germany. 32School
of Life and Environmental Science, Sydney Institute
of Agriculture, University of Sydney, Sydney, New
South Wales, Australia. 33Crop & Environment
Science, Harper Adams University, Newport, UK.
34Department of Biological Sciences, Rensselaer
Polytechnic Institute, Troy, NY, USA. 35Entomology
Department, Cornell University, Ithaca, NY, USA.
36Buglife - e Invertebrate Conservation Trust,
Peterborough, UK. 37Departamento de Biología,
Universidad del Valle, Cali, Colombia. 38Key
Laboratory for Zoological Systematics and Evolution,
Institute of Zoology, Chinese Academy of Sciences,
Beijing, China. 39School of Science, University
of Waikato, Hamilton, New Zealand. 40Vietnam
National Museum of Nature & Graduate School
of Science and Technology, Vietnam Academy of
Science and Technology, Hanoi, Vietnam. 41Centre for
Agri-Environmental Research, School of Agriculture,
Policy and Development, Reading University,
Reading, UK. 42Department of Plant Protection,
IPB University, Bogor, Indonesia. 43Department of
Conservation Ecology and Entomology, Stellenbosch
University, Matieland, South Africa. 44Department
of Environment and Energy, Canberra, Australian
Capital Territory, Australia. 45National Agricultural
Research Institute, Lae, Papua New Guinea. 46School
of Biological Sciences, Washington State University,
Vancouver, British Columbia, USA. 47Department
of Entomology, Faculty of Agriculture, Kasetsart
University, Bangkok, ailand. 48Agroecology,
Department of Crop Sciences, University of
Göttingen, Göttingen, Germany. 49Bio-protection
Centre, School of Biological Sciences, University
of Canterbury, Christchurch, New Zealand.
50School of Science and Health, Western Sydney
University, Penrith, New South Wales, Australia.
51Department of Biology and Ecology, Faculty of
Sciences, University of Novi Sad, Novi Sad, Serbia.
52Ecology and Evolutionary Biology, University of
Connecticut, Storrs, CT, USA. 53De Vlinderstichting
(Dutch Buttery Conservation) & Plant Ecology and
Nature Conservation Group, Wageningen University,
Wageningen, e Netherlands. 54Functional
Agrobiodiversity, Department of Crop Sciences,
University of Göttingen, Göttingen, Germany.
55IUCN SSC Mid Atlantic Island Invertebrate
Specialist Group, IUCN, Cambridge, UK. 56Natural
History Museum, London, UK. 57Chrysalis
Consulting, Hanoi, Vietnam. 58Zhejiang Provincial
Key Laboratory of Crop Insect Pests and Diseases,
Hangzhou, Zhejiang, China.
*e-mail: j.harvey@nioo.knaw.nl
Published: xx xx xxxx
https://doi.org/10.1038/s41559-019-1079-8
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Competing interests
The authors declare no competing interests.
NATURE ECOLOGY & EVOLUTION | www.nature.com/natecolevol
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Recent reports of local extinctions of arthropod species 1 , and of massive declines in arthropod biomass 2 , point to land-use intensification as a major driver of decreasing biodiversity. However, to our knowledge, there are no multisite time series of arthropod occurrences across gradients of land-use intensity with which to confirm causal relationships. Moreover, it remains unclear which land-use types and arthropod groups are affected, and whether the observed declines in biomass and diversity are linked to one another. Here we analyse data from more than 1 million individual arthropods (about 2,700 species), from standardized inventories taken between 2008 and 2017 at 150 grassland and 140 forest sites in 3 regions of Germany. Overall gamma diversity in grasslands and forests decreased over time, indicating loss of species across sites and regions. In annually sampled grasslands, biomass, abundance and number of species declined by 67%, 78% and 34%, respectively. The decline was consistent across trophic levels and mainly affected rare species; its magnitude was independent of local land-use intensity. However, sites embedded in landscapes with a higher cover of agricultural land showed a stronger temporal decline. In 30 forest sites with annual inventories, biomass and species number-but not abundance-decreased by 41% and 36%, respectively. This was supported by analyses of all forest sites sampled in three-year intervals. The decline affected rare and abundant species, and trends differed across trophic levels. Our results show that there are widespread declines in arthropod biomass, abundance and the number of species across trophic levels. Arthropod declines in forests demonstrate that loss is not restricted to open habitats. Our results suggest that major drivers of arthropod decline act at larger spatial scales, and are (at least for grasslands) associated with agriculture at the landscape level. This implies that policies need to address the landscape scale to mitigate the negative effects of land-use practices.
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Insects make up the bulk of terrestrial diversity (1). Reports of insect declines, best documented in Europe and North America, suggest that 40% of insect species in temperate countries may face extinction over the next few decades (2), although this figure is probably inflated (3). Other studies have highlighted falling insect biomass in Germany and Puerto Rico (4, 5), as well as threats to many insect taxa in Europe (5) and insect pollinators worldwide (6) that support food production (7). To protect insects, it is crucial that they are considered as separate species with distinct responses to threats, with particular attention to tropical insects and their habitats. Bees and butterflies may serve as an initial focus, but conservation efforts must go far beyond these iconic species. Halting habitat loss and fragmentation, reducing pesticide use, and limiting climate change are all required if insect populations are to be preserved.
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Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxo-nomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and midsummer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.
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We must start an ambitious and professional global programme to explore and preserve invertebrate biodiversity, says Axel Hochkirch.
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Biodiversity of insects is threatened worldwide. Here, we present a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers. Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world's insect species over the next few decades. In terrestrial ecosystems, Lepidoptera, Hymenoptera and dung beetles (Coleoptera) appear to be the taxa most affected, whereas four major aquatic taxa (Odonata, Plecoptera, Trichoptera and Ephemeroptera) have already lost a considerable proportion of species. Affected insect groups not only include specialists that occupy particular ecological niches, but also many common and generalist species. Concurrently, the abundance of a small number of species is increasing; these are all adaptable, generalist species that are occupying the vacant niches left by the ones declining. Among aquatic insects, habitat and dietary generalists, and pollutant-tolerant species are replacing the large biodiversity losses experienced in waters within agricultural and urban settings. The main drivers of species declines appear to be in order of importance: i) habitat loss and conversion to intensive agriculture and urbanisation; ii) pollution, mainly that by synthetic pesticides and fertilisers; iii) biological factors, including pathogens and introduced species; and iv) climate change. The latter factor is particularly important in tropical regions, but only affects a minority of species in colder climes and mountain settings of temperate zones. 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.