Case Study: Providing food and shelter for invertebrates in Autumn

Author: Catherine Jones, Buglife

As the days continue to shorten, temperatures drop and the morning frosts start to appear, the value of autumnal vegetation for wildlife should not be underestimated.

In addition to creating the striking frost-bitten scenery in autumn and winter, allowing tussocky grass and wildflower seed heads to remain uncut through winter, in field margins, along tracks and roadside verges, and in gardens, will provide food and shelter for invertebrates and other wildlife.

© Gethin Davies

The remaining seed heads of the summer flushes of wildflowers such as willow herbs, thistles and even dandelions supply food for goldfinches, linnets and other seed eating birds and shelter for invertebrates. Ladybirds and earwigs may shelter in large wildflowers seed heads.

© Guy Sharrock

© Jodie Randall

Tall tussocky grass provides shelter for many overwintering invertebrates, and spiders construct their webs between long fronds that collect water droplets in the early morning mists. Grass tussocks may also hide ‘runs’ where mice and voles move from place to place protected by the dense vegetation above. Carder bee queens, emerging from hibernation, will search for nesting sites at the base of grass tussocks in spring.

Autumn is a great time to cut areas of long grass, including wildflowers meadows, and to remove the cuttings to help wildflowers to thrive the following year which in turn produce nectar and pollen to feed our valuable pollinators. But leaving leaving some patches of long tussocky grass and tall wildflower seed heads back then has now provided food and shelter in hardest months and nesting opportunities next spring.

© Gethin Davies

Additional information on managing farmland for pollinators is available from:

Bug Life: Helping Pollinators at Farm Scale

Bug Life: Helping Pollinators at Field Scale

Case Study: Managing Farmland for Grey Long-eared Bats

Author: Craig Dunton, Grey long-eared bat Project Officer, Bat Conservation Trust

Species: Grey Long-eared bat:

© Craig Dunton/www.bats.org.uk

 

Why is farmland important for this species?

With as few as 1000 individuals In the UK, the grey long-eared bat is one of our rarest mammals. Their distribution is restricted to the southern coast (Devon, Dorset, Somerset, Hampshire, Isle of Wight and Sussex) and there are only 9 known maternity colonies; meaning that this species is on the brink of extinction in this country. Currently, work is being carried out to conserve this species as part of 'Back from the Brink' – a Heritage Lottery funded conservation project aiming to save 20 species from extinction. https://naturebftb.co.uk/

Farmland is vitally important to all bat species. 70% of land in the UK is used for agriculture, so for very mobile species that utilise the whole landscape, farming practices can have significant impacts on bat populations. Some bat species are more resilient than others, but for those that have very low populations, are particularly sensitive to light and disturbance, and have very specific habitat requirements, there are significant threats to their survival.

Like all bats, the grey long-eared bat needs some key elements throughout its range in order to survive and thrive.

Roosts: Bats utilise a wide variety of structures to roost in, as their requirements change throughout the year. Roosts are needed for different activities – hibernation roosts, maternity roosts, night feeding roosts (for some bats) – these are all needed at different times of the year, and different bat species choose different structures for different activities.

Many bats hibernate underground, using caves, mines, cellars and tunnels that have a cool and constant temperature that bats need to hibernate. Many farms have these types of features, so it is important to be aware of their importance for bats. Some bats roost in a variety of different tree features; cracks, splits, woodpecker holes, loose bark – so it is important to retain trees that have ‘interesting’ features.

Grey long-eared bats are mostly associated with man-made roosts – usually the roof spaces of large, traditional, stone buildings with slate roofs. There are some records of them using caves and rock crevices, but no records of them using bat boxes in England.

Many buildings on farms can provide important roosts for grey long-eared bats, particularly large stone buildings with slate roofs and large, open roof voids. These can provide vital maternity roosts, temporary day and night roosts and opportunities for hibernation. As all bat species are protected, if you are planning to carry out any work that might impact bats or their roosts, the National Bat Helpline will point you in the right direction, please email enquiries@bats.org.uk

Foraging sites: As with roosts, different species of bats have different types of habitats that they favour for foraging. All UK bat species are insectivores, and depending on their size, flight habits and other physical adaptations, different species need different insect prey and therefore different habitats for foraging in. Greater horseshoe bats are large bats and so favour large prey, particularly around the maternity period. Cockchafers and dung beetles are their food of choice. Daubenton’s bats are often seen foraging over water, trawling insects from the surface of the water with their specially adapted, large hairy feet.

© Craig Dunton/www.bats.org.uk

Grey long-eared bats have a close association with unimproved lowland grassland and riparian (wet) habitats such as meadows and marshes.

Managing permanent pasture more extensively with very low or no inputs will benefit grey long-eared bat populations, offering more opportunities for invertebrates including the moths and craneflies that grey long-eared bats favour. Managing land to maintain or increase species diversity (more flowering plants) as well as structural diversity (a range in sward height), will give insects food and shelter resources. If possible, consider transitioning land back to hay meadow management as opposed to silage production, as this allows insects and plants to complete life cycles and thrive.

In terms of cultivated land, increase pollen and nectar plots and wildflower margins, and manage by cutting or grazing to maintain plant diversity. These areas alongside trees and tall hedgerows have proven benefits for some bat species. Minimise pesticide use and consider crops that contain lots of flowering plants such as herbal leys.  Within arable land, conservation headlands or low input cereals can be beneficial if management results in increased invertebrate numbers. These are all ways of increasing foraging opportunities on less productive areas of land for grey long-eared (and other) bats.

Farming organically has many advantages, including huge benefits to biodiversity, natural resource protection and reducing greenhouse gas emissions. Following organic principles should be considered if aiming to encourage bats and other biodiversity.

Connectivity: For so much of our wildlife, good habitat connectivity is critically important. Linear features in the landscape such as hedgerows, watercourses and ditches, enable different species to flow freely through the landscape, enabling opportunities for feeding, interacting and breeding. For bats, good connectivity is vital, as many bats use linear features to navigate through the landscape, using their echolocation to move from roosting sites to foraging sites. When these features are well managed, they can also provide foraging opportunities as well as providing obvious features to allow free movement. Extensive hedgerow management (2-3 year cutting cycle) allows hedgerow plants to flower and fruit, providing vital resources for insects. Buffer strips along streams and rivers not only provides increased opportunities for foraging, but can also protect watercourses from nutrient and pesticide run off, protecting aquatic flora and fauna.

For more information on land management for grey long-eared bats contact Craig Dunton (Grey long-eared bat project officer) on cdunton@bats.org.uk

 

 

 

Case Study: Helping hedgehogs on farmland

Author: Nida Al-Fulaij, Grants Manager, People’s Trust for Endangered Species

Species: Hedgehog

Why is farmland important for this species?

Hedgehogs are found throughout the UK in all habitats. They have historically been associated with farmland for centuries. Hedgehogs are insectivores, foraging in fields and on grassland for worms, and along field margins and at the base of hedgerows for beetles, snails and other invertebrates. They are considered a generalist species, inhabiting most areas of our countryside, our villages and many areas of our towns too. However, as the dominant habitat in the UK, farmland is particularly important for hedgehogs.

Hedgehogs, like all animals, need to feed, hide from predators and find mates. A variety of habitats that provide foraging areas and secure nesting sites is ideal. Both arable and pasture land can support healthy hedgehog populations. Wide, species-rich hedgerows with buffers of grassy margins on either side provide safe ‘highways’ for hedgehogs to move around the landscape. Hedgerows with wide bases that are managed on rotation should have healthy invertebrate populations for hedgehogs to feed on. Old hedges with dense root systems and lots of deciduous leaves are ideal for them to use as nesting sites, both during the summer and in winter as hibernation spots.

The denser the network of hedges, the more securely hedgehogs can move around, and the higher the availability of prey species for them to feed on.

Recently ploughed fields can provide a bounty of earthworms and other prey; hedgehogs can be found in-field taking the opportunity to feed on invertebrates once crops have been harvested.

Recent studies show hedgehogs are found nearer to farm buildings. These areas could be providing safety from predators on farmland with less robust and fewer hedgerows, and larger fields.

Hedgehog (c) Ben Andrew (rspb-images.com)

Habitat management

Hedgerows:

Increasing hedgerow availability provides more nesting and foraging areas for hedgehogs. Ensure that hedgerows are species-rich, contain native trees and are as wide, high and dense as possible. Maintaining hedge bases at least 2m wide with minimal or no gaps provides secure safe nesting sites. Managing hedgerows on a 3 year rotation ensures that hedges remain diverse and robust.

Field margins:

Field margins provide buffer zones to protect hedgerow bases. 2m margins in arable fields and 3-6m margins in pasture ensures the hedges are protected from trampling and grazing, whilst the grassland provides extra invertebrate prey. Beetle banks also provide buffer zones and extra foraging areas.

Fields:

Smaller field sizes with a mixed crop provides greater variety, and therefore greater food security, for hedgehogs and other wildlife. Increasing hedges and field margins on farms with fewer, larger fields, provides habitat for hedgehogs. Reducing tillage or moving to no-till or conservation agriculture reduces soil compaction, increases soil invertebrates and improves and increases the depth and quality of the soil organic layer.

Pesticide & herbicide use:

Reducing pesticide and herbicide use means that more invertebrate prey, in particular earthworms, will be available on farmland for hedgehogs to feed on.

The above management measures recommended to provide a healthy landscape for hedgehogs are typically those associated with traditional farming practices. There should be no problems, though many of the measures may be more time-consuming than those associated with farming on a larger scale.

Hedgerow with grassy margin (c) Gethin Davies

Peoples Trust for Endangered Species (PTES) and British Hedgehog Preservation Society (BHPS) have created an advice note detailing management and stewardship options that will benefit not only hedgehogs but other wildlife too (see link below).

Benefits and costs

Creating and managing hedgerows sensitively has financial costs but there are stewardship options available; individual ones for the management regimes listed above are detailed in the attached advice note.

Managing a farm for a species such as a hedgehog involves looking at the farm as a whole. Unlike species that fly, such as butterflies, hedgehogs needs the entire landscape to be suitable in order to thrive. Consequently, many of the management techniques recommended to improve habitats for hedgehogs will also provide a healthier landscape. A denser proportion of hedges and associated smaller field sizes both help to reduce soil erosion. Reducing tillage improves soil organic matter and reduces soil compaction.

PTES guide - How to help rural hedgehogs