Landscape-scale species monitoring of agri-environment schemes in England

This final project report evaluates landscape-scale species responses to agri-environment schemes (AES) management in England. It was part of the Natural England monitoring and evaluation project 'LM0465', focusing on pollinators, birds and other taxa across 54 survey squares from 2017 to 2021.

The evaluation aimed to determine whether key mobile taxa, such as butterflies, moths, bats and birds are affected by AES management beyond individual option or agreement boundaries, particularly across large spatial scales and multiple taxa. It also considers impacts on the abundance, species richness and diversity of these taxa. The survey covered six regions in England over several years, collecting baseline data for future comparisons and further large-scale modelling.

The main objectives of the evaluation include:

1. To assess spatial associations between AES management and the abundance or diversity of mobile taxa at local (1 km squares) and landscape (3 × 3 km) scales.
2. To identify whether different mobile taxa respond similarly to AES management at these scales.
3. To analyse if the richness, abundance or diversity of these species increases over time due to AES interventions.
4. To provide a foundation for future resurveys that could assess population changes as a result of AES management interventions.

The study applied a field-based survey methodology using habitat and option mapping to categorise land use and ecological features. Data collection was carried out through botanical surveys, insect taxa assessments and bird counts. Each field parcel was surveyed for habitat types with information directly recorded using GIS-based tools for habitat validation and option implementation mapping. Furthermore, functional trait analyses were conducted on insect species to understand their responses to habitat management.

The study utilised a combination of field survey data, satellite imagery and GIS layers, including the Land Cover Map 2007 and ordnance survey data for habitat classification. Existing species distribution records from national databases, as well as peer-reviewed literature, were used to validate the survey results.

For the analysis, ecological factors were considered based on species abundance, richness and diversity across surveyed taxa (e.g. birds, insects and plants). The study focused on factors such as species presence/absence, floral diversity and habitat condition. Specific functional traits, including species mobility and feeding preferences, were assessed to determine the impact of agricultural management on biodiversity.

Limited sample sizes for some taxa, potential unobserved interactions at smaller scales, variability in AES option implementation and missing data due to the COVID-19 pandemic in 2020 affected survey schedules.

Strong positive relationships were found between landscape-scale AES gradients and the abundance, richness and diversity of mobile taxa, particularly butterflies and moths. Butterflies showed a significant response to landscape AES gradients, with survey squares at the higher end of the AES gradient having, on average, 53% more butterflies than those at the lower end (an estimated increase of 117 butterflies per square). Moths, especially micro-moths, also showed strong positive responses with a 14% increase in species richness in squares with higher AES gradients.

Bat species such as Barbastelle and Daubenton’s bats exhibited small positive effects from AES management at the landscape scale. There was a 1% increase in the likelihood of these bat species being present in squares with higher AES gradients, although the overall effect sizes were modest.

There was no strong evidence that AES gradients affected the abundance, richness or diversity of bees or hoverflies. Parasitic bumblebees and hoverflies with detritivorous larvae were slightly more abundant in areas with higher AES gradients, but the effects were weak and inconsistent across the study. Bird responses were minimal with no clear relationships between bird community metrics and AES gradients. Some weak positive associations were found for winter bird abundance and species richness, but the overall evidence for AES effects on birds was limited.

Habitat diversity, rather than AES gradients, had a stronger influence on bird responses. Within-square analyses revealed significant effects of AES at the option patch level for butterflies and bumblebees. These species were more abundant and diverse on AES managed patches compared to non-managed patches, with a notable increase in butterfly abundance (+11 butterflies per transect section) and bumblebee abundance (+6 bumblebees per transect section). However, these within-square effects did not always scale to the broader landscape level when aggregated across multiple survey squares.

The findings indicate that AES management is particularly effective for certain mobile species like butterflies and moths at the landscape scale, while other taxa like birds, bees and hoverflies show more variable or limited responses. The study suggests that focusing AES efforts on larger landscape scales may be more beneficial for highly mobile species, while the impact on other taxa may require further targeted interventions.