Written evidence submitted by the UK Centre for Ecology & Hydrology (INS0022)

Executive summary

  1. The UK Centre for Ecology & Hydrology (UKCEH) welcomes the opportunity to submit evidence on insect decline and UK food security to the Science and Technology Committee.

 

  1. UKCEH is an independent, not-for-profit research institute carrying out excellent environmental science with impact. We have a long history of investigating, monitoring and modelling environmental change and take a whole systems approach to understanding the environment, how it sustains life, and the human impact on it.

 

  1. We identify key drivers of biodiversity change, develop tools and technologies for monitoring biodiversity, and provide long-term data for assessing the status and trends of species populations. We also provide robust socio-economic and environmental solutions for restoring biodiversity and increasing resilience. 

 

  1. Please note that UKCEH scientists are currently contributing to relevant ongoing research funded by Defra, including the National Honey Monitoring Scheme, the Butterfly Monitoring Scheme, and the regular State of Nature Reports.

 

  1. We would be happy to discuss the evidence provided with the Committee. 

 

Glossary

Species abundance

Species abundance is the number of individuals of each species in an area.

Species distribution

Species distribution is the distribution or recorded presence of species across geographical space.

Species occupancy

Species occupancy is the proportion of sites (typically 1 km squares) occupied by a species.

 

Evidence

The current evidence base for insect abundance in the UK, and the gaps in scientific understanding that require further research.

  1. Overview. Data on insect abundance from long-term, structured monitoring across the UK is available for a relatively limited number of taxonomic groups: butterflies (UK Butterfly Monitoring Scheme, since 1976), moths and aphids (Rothamsted Insect Survey, since 1964), freshwater insects (Environment Agency, since 1991) and more recently bumblebees (BeeWalk transects, since 2010) and a range of pollinators (UK Pollinator Monitoring Scheme, since 2017).


Much of our evidence is therefore derived from records of species presence submitted by naturalists to volunteer-led schemes and societies. These data are analysed by the Biological Records Centre at UKCEH to produce estimates of species occupancy and distribution, which are in turn used to produce the UK Biodiversity Indicators and as the basis for scientific research.


Volunteer recording plays an important role, providing a wealth of records that go back many years. However, unstructured records typically suffer from significant sampling bias. Therefore, estimates of species distribution may not reflect either the true status and temporal trends of all species, or the relative abundance of individuals and their ability to provide services to benefit human wellbeing and ecosystem resilience. For the majority of insect groups, the lack of long-term data on abundance makes it difficult to understand our true baseline.

 

UKCEH is leading three projects due to provide significant new evidence on the status of UK insects in the coming year (see below).

 

  1. Current evidence: Analyses of trends in species distribution, occupancy and abundance of insects in the UK over the past 50 years reveal a mixed picture, with patterns of change varying across taxonomic groups, over space and time. Many species are in decline, but some show a more stable trend in recent decades, while others have increased, remained stable or had insufficient records to allow detection of a trend.

 

For pollinating insects, models of species occupancy for 353 wild bee and hoverfly species in Great Britain between 1980 and 2013 found evidence of declines across a third (33%) of species, likely driven by pressures such as habitat loss, climate change, and pesticides. Losses were concentrated in rare species and linked to specific habitats, with a 55% decline among species associated with uplands. In contrast, some species such as dominant crop pollinators increased in occupancy by 12%, possibly in response to agri-environment measures. The official UK Biodiversity Indicator for pollinating insects was updated in 2022. The indicator shows a 21% decline in occupancy of wild bee and hoverfly species between 1980 and 2019 and a 4% decline since 2014. 

 

Evidence on the state of larger moths shows that total abundance of moths recorded in the RIS light-trap network in Britain decreased by 33% over 50 years (1968-2017).  Four times as many moth species decreased in abundance as increased. Meanwhile, data on distribution trends from records of species presence co-ordinated through the National Moth Recording Scheme are more variable. Of 511 species recorded, 32% (165) species decreased and 37% increased in distribution between 1970 and 2016. For butterflies, long-term trends show that 80% of species in the UK have decreased in abundance or distribution or both since the 1970s.

 

Freshwater macroinvertebrates, including insects, support several different ecosystem functions and services and constitute the bulk of the diets of many fish, bird and bat species. Analysis of a long-term dataset of river macroinvertebrate abundance collected from 2002 to 2019 across 5009 sampling sites in England reveals a complex picture, with abundance trends varying across taxa, trophic groups and river typology.

 

The State of Nature Report 2019 reported a 16% decline in abundance of butterflies and a 25% decline in moth abundance in the UK between 1970 and 2016. The occupancy indicator for insects also showed a decrease in average species distribution of 10% over the long term (1970-2015), and 8% over the short term (2011-2015).

 

  1. Forthcoming evidence: The State of Nature Report. The new State of Nature Report due to be published in Autumn 2023 will report occupancy trends for 5014 species of invertebrates and disaggregated metrics by key ecosystem function, including pollination, pest control and freshwater nutrient cycling, at UK and country level. 

 

Drivers and Repercussions of UK Insect Declines. Research from the NERC-funded Drivers and Repercussions of UK Insect Declines (DRUID) project, will be published in 2024. This will contribute to the evidence base for changes in insect abundance and distribution, and to our understanding of the environmental causes for these in the UK. The project has collated updated species occurrence data for 17 terrestrial and freshwater insect groups, to calculate new trends in occupancy for over 2500 insect species, which will be summarised alongside a detailed description of the potential implications of data gaps and sampling bias.

 

The UK Pollinator Monitoring Scheme. The UK Pollinator Monitoring Scheme (UK PoMS) was established in 2017, using structured surveys to understand how insect pollinator populations are changing across the UK. The first five-year analyses are due to be published by UKCEH and JNCC in summer 2023, and PoMS-generated records have already contributed to a major current revision of the Red List for British aculeates (bees, wasps, ants). It is critical that the UK PoMS partnership continues to receive funding after the 2025 end date of the current contract with JNCC.

 

  1. Evidence gaps 

 

  1. References

 

The effects of pesticides, such as neonicotinoids or other agricultural control methods on insects including pollinators and their impact on UK food security.

  1. Overview: Despite improvements to policy and management over the last 30 years, the way we are managing agricultural systems is failing to conserve and restore insect biodiversity. Integrated Pest Management is critical to ensuring crop yields while minimising the risks to human health and the environment. Pesticides used in crop and plant protection include fungicides, herbicides and acaricides as well as insecticides; the evidence cited here focuses on the latter.

 

  1. Current evidence. The UK Centre for Ecology & Hydrology led much of the research which informed the UK’s decision to support an EU-wide ban on three neonicotinoids for outdoor agricultural use in 2018. A large-scale replicated field study in UK, Germany and Hungary demonstrated the negative effects of neonicotinoid use on honeybees, bumblebees, and wild bees. In addition, we led an assessment of 62 wild bee species over 18 years showing that those feeding on neonicotinoid-treated oilseed rape have undergone significantly greater declines in their distributions in England than non-oilseed foragers.

 

Research led by our scientists also shows that neonicotinoids continue to be detected in                             honey produced by honeybees foraging in agricultural landscapes even after the ban on                             neonicotinoid use, indicating that the effects of these pesticides persist in the environment;               and reveals evidence of increased disease risk for honeybees resulting from sub-lethal                             exposure to insecticides at a national scale.

 

  1. Forthcoming evidence: Preliminary results from the NERC-funded ChemPop project show that insects are declining in occupancy across Great Britain, but declines tend to be stronger in areas of intensive agriculture. This effect was particularly strong for bees, which show declines twice as severe in areas with 50 to 100% cropland cover. 

 

  1. References

 

The extent that biodiversity initiatives, such as creating reservoir populations, are addressing insect decline and whether there is sufficient co-ordination with the UK food system.

  1. Overview: Applied research, carried out in collaboration with the farming industry, has demonstrated clear positive impacts on insect abundance and species richness from land management interventions such as Environmental Stewardship schemes, however a joined-up approach at landscape scale is essential to ensure that insect populations can move between farmed and unfarmed or protected areas. Continued support for national-level surveillance is necessary to measure the impact of such interventions.

 

  1. Current evidence: Research led by UKCEH demonstrates that wildlife friendly management supporting ecosystem services is compatible with, and can even increase, crop yields. For example, increasing areas of non-cropped natural habitats in productive arable farmland (from 3% to 8% cover) supported insect populations providing pollination and natural pest control over a five-year rotation. Despite taking land out of productive agriculture, there was no adverse impact on overall yield in terms of monetary value or nutritional energy.

 

Agri-environmental schemes establishing flower-rich field margins or creating species-rich semi-natural grassland increase populations of insects in intensively managed agricultural landscapes and can be used to help support pollination services and natural pest control for arable and high value fruit crops, an integral part of Integrated Pest Management.

 

Our research shows that UK protected areas, such as SSSIs (Sites of Special Scientific Interest), are failing to conserve invertebrate biodiversity and that more effective protected areas are needed to address insect declines. While UK protected areas on average support 15% more invertebrate species and double the number of rare species than unprotected ones, declines in occupancy were of similar magnitude over the same period, with pollinating insects suffering particularly strong declines between 1990 and 2018.

 

  1. Forthcoming evidence: UKCEH have led a Defra-funded assessment on the environmental impact of land management actions being considered for future Environmental Land Management (ELM) schemes, referred to as the 'Defra Qualitative Environmental Impact Assessment project'. This involved developing an evidence review for impacts of agri-environmental management interventions to inform an expert-based integrated assessment, where actions were given a qualitative impact score against Ecosystem Services relevant to environmental objectives for ELM schemes.


This assessment is a key part of the evidence base to inform which actions should be included in future schemes, as well as an important source for appraising the potential of schemes. Defra intends to publish the QEIA report in the coming months. It indicates those interventions that are likely to have the most positive impact on ecosystem services provided by insects (pollination and pest control) as well as on overall biodiversity, and where sufficient evidence was available, on rare and priority species on farmland in England.

 

  1. References

 

Whether the threat to UK food security from insect decline receives sufficient cross-government priority.

  1. Integration could be improved across different departments. The National Pollinator Strategies led by devolved administrations are a good example of this. For example, Defra could work with the Department for Health and Social care and the devolved nations to strengthen links between conservation of insect biodiversity, human health (through nutritious diets rich in insect-pollinated crops) and wellbeing (through connections with nature and green space).
  2. Accelerating the reversal of biodiversity loss requires the redirection of financial flows to support biodiversity net gain as well as the creation of effective monitoring, verification and enforcement of biodiversity credit schemes. There is a need for an integrated policy approach between departments including Defra, DSIT and HM Treasury, which is joined up with the finance sector. The implementation of such an approach can be supported by geospatial tools, coordinated by the Geospatial Commission. 

 

References

 

Additional policy initiatives and solutions needed in the UK and internationally to reduce and reverse the trends in insect decline.

  1. Overview: The issue of insect decline is long-term in nature and requires a sustained response over a number of years. The role of insects in providing ecosystem services needs to be integrated with achieving net zero and sustainability goals for agriculture. A long-term approach to the funding of environmental monitoring is required to ensure consistency in data to provide robust evidence over time.

 

There is a need for ongoing monitoring and surveillance, including for invasive non-native species. Early detection through initiatives such as the Asian Hornet Response Plan developed by the Great Britain Non-native Species Secretariat (GBNSS) can prevent the spread of species detrimental to the environment, industry and public health, as well as to other insects.

 

In some cases, detailed understanding of the life history of insect species is required to underpin conservation. The successful reintroduction of the large blue butterfly provides an example of successfully linking habitat management and restoration to conservation efforts. Such detailed studies will be important for other species going forward.

 

Furthermore, understanding the effects of climate change and land-use change is important to inform ongoing habitat management and conservation. There is a need for landscape approaches linked to life history studies.

 

Local government and communities are critical to achieving the Nature Recovery Plan, a key commitment of the 25 Year Environment Plan, and delivering on the Green Recovery Challenge Fund. There is a need to increase support for monitoring at regional and local scales to support local governments in achieving these policy goals and monitoring them.

 

Along with this, there is a need to provide support for initiatives which link practitioners with scientists and national monitoring schemes. For example, the Chilterns Conservation Board "Tracking the Impact" takes nationally applied monitoring methods and applies them at local level.

 

  1. References

www.ceh.ac.uk/case-studies/case-study-large-blue-butterfly

28 April 2023