How to Rewild

Dwarf Shrub Heath

Habitat Management Plan

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Dwarf Shrub Heath
Habitat Guide

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These are habitats that have benefited from our impact on the environment. Lowland and Upland Heathland developed when woodland was cleared for livestock grazing, and the habitat is, in many places, maintained for grouse shooting and extensive (low intensity) grazing. In contrast, the range of Mountain Heaths now extends far below its historic mountaintops, because high populations of deer eat young trees that would otherwise take the place of this habitat.

However, these habitats aren’t human-made – they’re communities of organisms which exist without our influence in some cases. You might find Lowland Heath in coastal areas as a transition community on sand dunes, or Willow Scrub in mountains above the treeline. This wild origin means that healthy Dwarf Shrub Heath can boast a diverse and abundant population of wildlife, especially in summer when it is home to breeding birds.

There’s a lot of political back-and-forth about the value of heathland because some land managers burn gorse and heather to resist succession (‘muirburn’). Any habitat with lower structural diversity like this will have lower species diversity and abundance (see the 3 D’s). This means that, while a burned heathland habitat can support valuable populations of threatened breeding birds, it is more valuable overall to biodiversity and bioabundance when there are stands of trees, healthy ponds, bogs etc. The relative value of these threatened species reliant on muirburn, and the overall ecosystem health is up for debate. A mosaic habitat is less likely to be found on burned, degraded heathland, though it is true that some management needs to take place to resist succession and maintain the mosaic.

Sub Habitats

A fairly open habitat on acidic and peaty soils, typically below 300m in elevation with a characteristic mix of plant species (see UKHab website) that is dominated by heathland species such as gorse or heather.

A fairly open habitat on acidic and peaty soils, typically above 300m in elevation with a characteristic mix of plant species (see UKHab website) that is dominated by heathland species such as gorse or heather.

A fairly open habitat which occurs above the treeline, with a characteristic mix of plant species (see UKHab website) that is dominated by scrub, such as heather and willow.

Value

The UK holds about 20% of the world’s Lowland Heathland, and this habitat, along with Upland Heathland, is home to a wide variety of reptiles. In fact, all 6 species of British reptiles are found here, as the mix of low scrub, exposed stone and soil, and dense grasses makes this ideal habitat for them. Alongside reptiles, heathland is also home to unique bird species like the enigmatic Nightjar, Dartford Warbler and Stonechat.

Poor, typically acidic soils, which overlie thin peat or rock near the surface of the ground, shape the vegetation that is found in these habitats. Low shrub in the form of Heather and Cross-Leaved Heath, as well as Gorse, tend to dominate Heathland, while low-growing Willow is found in Willow Scrub areas. In places, stands of pioneer trees like Birch and Aspen can be found, and this habitat may be colonised by non-native Rhododendron.

The structural diversity of healthy heathland can be high, as ponds, streams, bog, heather, scrub and woodland transition into one another in a mosaic landscape. This patchwork is valuable for a diverse range of plants, invertebrates, birds, mammals, reptiles and amphibians. That is why, despite the human-created nature of the habitat, conservationists have been battling to protect the remnants of lowland heath for the past century (we have just 16% of what existed in 1800). But degraded heath, where muirburn is practised, and/or deer and sheep populations are very high, can be of lower value as a monoculture of heather tends to dominate.

Gorse scrub
Gorse can tend to dominate this habitat as its rapid growth and defensive thorns are effective at resisting control measures.

Protect

The non-native invasive species Rhododendron ponticum is ideally-suited to colonise this habitat, as its tall evergreen foliage shrouds the low-growing vegetation and thrives in acidic soils. The plant’s toxic leaves make it inedible to livestock and deer, so it spreads unimpeded. This means it is important to identify and remove any Rhododendron as soon as it appears, to minimise future management costs. Pulling plants is effective, as is cutting them and treating the drilled stumps with a herbicide to prevent regrowth. But the seeds may persist in the soil, so it is worth checking back to ensure regeneration does not occur.

Encroachment of scrub and trees can cause a heathland to close over and turn into scrubland, then woodland. While this is a natural process, it does also represent the loss of a Priority Habitat, and in the case of SSSIs, landowners will be required to maintain the status quo. A mosaic landscape tends to have higher biodiversity, so scrub removal is an important part of many conservationists’ work. Burning of heathland has both carbon and biodiversity implications – so the use of brushcutting equipment is likely to have less of an impact.

In general though, scrub management is most cost-effectively achieved using livestock. Breeds like Highland Cattle can graze and browse at low density alongside primitive horses like Dartmoor and Exmoor Ponies, which create valuable wild ‘grazing lawns’ that are home to threatened species of wildflower.  The Rare Breeds Survival Trust can offer advice on which livestock is suitable for your particular conditions. The occasional wildfire (through human or natural causes) is to be expected in a dry heathland habitat, and it is likely to aid in scrub management over the long term, at low frequencies.

Bare ground is an important part of a mosaic landscape, and it may revert to shallow pools – ephemeral ponds – especially in the presence of larger livestock like cattle and ponies. Cattle are also ideal for managing bracken, as they tend to crush the plants, while ponies are better at browsing gorse (though this may not be enough on its own to resist its dominance). Primitive sheep like Soay are most effective at controlling heather, creating variability in the low scrub, and more opportunities for wildflowers, bog and grasses. Due to the fragility of this habitat, grazing tends to take place in the summer months, though low density winter grazing may create valuable open and muddy patches of habitat. Ideal stocking density is significantly lower than in grassland, at about 0.22 LU/ha in SW England.

Willow scrub
Fast-growing Willow can outcompete other vegetation, to rapidly succeed into woodland on Dwarf Shrub Heath.

Restore

A uniform heathland with thousands of hectares of knee-height heather, managed with sheep grazing and/or muirburn is not a natural ecosystem. Shifting these habitats towards a wilder approach would likely reduce costs and create more climate change-resilient uplands. A mosaic habitat resists the spread of wildfires, especially where healthy bog is present (this is degraded by burning). Healthy heathland also reduces downstream flooding and increases the storage of carbon in the soil and above-ground vegetation.

This doesn’t necessarily mean allowing heathland to succeed to forest or converting it to bog, but it does mean creating a mosaic habitat in places where there are miles upon miles of heather. This mosaic should arise naturally through regeneration if sheep numbers are reduced and muirburn stops. However, if tree and bog seeds and plants have become depleted over time, as is often the case in these habitats, it may be necessary to intervene. 

In Scotland, Trees for Life grow locally-harvested tree and scrub seeds in bulk and plant out the cultivated seedlings – this appears to be an effective strategy for establishing a locally-appropriate, diverse ecosystem. It may be possible to partner with a local plant nursery on a project like this, as is the case with sphagnum cultivated by Celtic Wildflowers for the Lost Peatlands Project.

Bits of land with specific conditions tend to be ideally suited for certain habitats, and working against this ‘will of the land’ can be counterproductive. If you have an exceptionally-wet peat soil, then the land is likely to happily revert to bog, provided the water table is consistent throughout the year. If it’s the sides of a secluded valley in the uplands, your patch is likely to ‘scrub-up’ and shift towards Temperate Rainforest over time. Old maps and place names may help you identify which habitat had pre-existed the heathland, or an ecologist may be able to offer some expertise. Getting these ancient habitats re-established could take a large upfront effort due to missing species, but this will trail off over time as natural processes take over. Biodiversity will then remain high and inputs will be low, as the land will tend to maintain itself, provided you have the right balance of grazing (this could be very low in e.g. temperate rainforests or high in Acid Grassland).

Where a high deer population artificially maintains a heathland habitat, then measures to reduce the numbers could boost local biodiversity. This has proven effective in restoring a mosaic upland in the Cairngorms, where deer were culled, with the population reduced to a much lower, more sustainable level. The cull needs to be maintained over time, in the absence of predators like lynx and wolf, which would naturally control the number of deer. However, there tends to be a large initial reduction in numbers, and then a small ongoing cull each year.

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