Lowland Heathland Management for selected Insects - the need for bare, undisturbed soil for nesting.

Habitat features of heathland sites

Footpaths, Tracks and Bridleways across heathland

On most lowland, dry heathlands today the only bare ground that is evident is on the surface of the heathland walking and horse riding routes. This bare ground in mosaic with the heather dwarf shrub vegetation is just as important as the heathland itself especially where it is situated in open and sun-exposed areas of the heath. It is in such locations that important elements of the heathland fauna make their homes. This is the solitary bees and wasps by digging nest holes in the sand of such situations in which their next generations will develop along with their "cuckoo" species, parasites, parasitoids and other exploiters of the nest resources they create, such as various beetle species and shadow flies.

ABOVE: A dry heathland eroded track, a part of a richly biodiverse lowland heathland situated in East Hampshire. The exposed bare ground suits a variety of insect species for nesting. © Copyright SMiles.

ABOVE: A typical solitary wasp inhabitant of sandy paths and tracks, Ammophila pubescens' attending to its' nest hole in the natural soil of the track on a dry, sun-exposed lowland heathland. This species is the host in the pre-pupal state to the Mottled Bee-Fly, Thyridanthrax fenestratus. © Copyright C.Spilling.

In a few cases the sand lizard occupies such tracks and the bare ground of them which it uses to excavate and lay its' eggs in. These situations if over used by people become heavily trampled creating loose sand that all too easily runs off the heath in rainstorms. Thus this is one of the sensitivities of heathland, too many people if located nearby will ensure that much of the insect and other faunas is lost due to trampling. Equally if there are not enough people or grazing animals using these routes then they may grow over, though usually this is much less of a problem and this limited use is often beneficial as is the consequential lack of disturbance.

Many of such tracks are often walked by dog walkers but the results of such walks often show up as the growth of various grasses at the edge of the path or track because it has been enriched by the dog faeces and urine as a result of the walk. The owner's feet may provide a benefit in helping to keep the path open but the presence of people's pets is potentially more damaging to the nutrient poor and usually acidic soils of the heathland.

National Cycle Trails/Long Distance Trails/Access for All/Rights of Way

The conversion and promotion of many heathlands and especially of the footpaths, tracks and bridleways on them into major leisure routes in England is a continuing disaster for the species that nest in or near them. Rights of Way for humans can produce a benefit for wildlife provided the usage is not constant and on a daily basis, the preference is for no more than five to ten people for each route per day on foot but preferably less use. But particularly since the introduction of the Countryside and Rights of Way Act 2000 (CROW) and the increases in mountain bike use, access and disturbance to ground nesting heathland birds and disturbance of the other wildlife that use heathland is getting worse and worse. Examples of particularly bad routes that pass over heathland are The Shipwright's Way on the greensand heaths on the boundary between Hampshire and West Sussex, the Sika Trail in Dorset and the bridleways that criss-cross Chobham Common, Surrey north of the M3 motorway. This is especially the case since government and voluntary sector organisations have got involved and are now actively promoting the so-called health benefits to humans of access to the remaining UK countryside, with little consideration of the other users of it, our wildlife, for whom it is their home!

The use of continuous tracked wheels of mountain bikes and other bicycles which began in Summer 2013 to churn up the soil of the track used for the Shipwright's Way across Weaver's Down in Hampshire, has now in 2015 and onward resulted in it becoming fully and disastrously churned up for the soil nesting insects that formerly used the bare sand to nest in. This threatens the success of the nesting of the host wasp - Ammophila pubescens - of the Mottled Bee-fly as the nest holes excavated by the wasp are beginning to become constantly filled up with the loose soil during the summer breeding season, as I predicted they would in my pleas to the local authorities for this site not to be used for cycling. This in turn threatens the population of the Biodiversity Action Plan species' the Mottled Bee-fly, Thyridanthrax fenestratus here, because cyclists are now fanning out all over the area on every footpath and track to their detriment. A disaster caused by the failure of Natural England and the Ministry of Defence, as well as the South Downs National Park Authority (SDNPA) in the opinion of this website promoter, to oppose the growth of cycling in this lowland heathland area.

Sadly the wildlife trusts in the south of England are also causing the same damage by surfacing the former bare ground on the bridleways of the heathland on Chobham Common (North). This Chobham situation is a particularly bad example, which encourages even more public use and disturbance of this site by dog-walkers and cyclists. Yet this site is or perhaps was one of the best sites in England for our solitary bee and wasp fauna as indicated by the comprehensive lists of these species for this site that occurred on it up to 1977 (Entomologist's Gazette). The facts that a wildlife trust as site manager and a county council as site owner and the Government organisation, Natural England are all involved in the destruction of the insect biodiversity of this site is a disgrace in the opinion of this website promoter.

ABOVE: A hard surfaced track passing through heathland, a modern disaster, an example of official vandalism. Everything that may have nested here is now entombed and only the few small edges that survive provide any opportunity for our bare ground insects to nest in. This illustrates the selfish lack of consideration shown for wildlife by the land-owning and managing local councils and other authorities in the UK today, just to support cycling. © Copyright SMiles.

Hard or soft surfacing of trails - this is bad practice

The other consequential demand is that such bridleways and tracks used on heathland should be surfaced to facilitate safe access for all human users and easy access for the fire brigade, often needed because of the bad habits of the human visitors in setting fire to the heaths. So a surfacing of stones, hoggin, or woodchips, in some cases underlain by canvas is employed and sometimes stones of a calcareous nature are brought in, into an acid heathland situation, thus enriching the sites. Because such stone tracks also offer niches, cracks in between the surfacing materials which then make such tracks capable of supporting plant growth, there is the potential for damaging fires to jump these tracks much more easierly as they then no longer offer a barrier to fire. This surfacing destroys the biodiversity of the bare ground habitat killing all the insects and other invertebrates that occupy it and its' application and spread by various so-called management experts and local authorities needs to be curtailed or stopped.

This is especially the case on lowland heathland and in other sites, such as woodlands that support large insect populations that nest in the exposed, open soil of rides, tracks and bridleways. There is a compromise that can be achieved by just surfacing the middle two metres of such tracks if this must be done and leaving one to two metres, depending on the width of the track, on either edge for bare ground inhabiting insects to continue to use.

The traditional management of heathland and the bare patch creation that occurred as part of this management

In the past bare ground was created incidentally by the methods used by the population to exploit the natural resources provided by the heathland habitat. The right of turbary as one of the old commoning practices for extracting turves and peat for fuel from the heaths helped create incidental mosaics of bare ground patches. In lowland heathland areas this method had virtually ended by the early years of the twentieth century. Common in soil, as a right to take sand, gravel, stone or other minerals for the use of the heathland commoner in or about his home also enabled the use of sand to be placed on the floor of the home. Some aspects of this use continued to the mid-part of the twentieth century in England. Finally setting fire to the heath was done to encourage fresh green growth for grazing animals, often these fires would go out of any control. But as today all these methods enabled bare ground to be exposed or created.

Bare patch creation by hand digging or mechanical digger excavation

Common Standards' Monitoring was introduced by the Joint Nature Conservation Committee (JNCC) in 1998, it was designed to select attributes for monitoring on specific habitats across the UK. On lowland heathlands one of the target attributes is bare ground. The general target on dry heathland is "for at least 1% but not more than 10% cover" of the bare ground feature. Ideally it should be in mosaic with the dominant dwarf shrub "heather" vegetation. With the loss of the only consistently occurring micro-habitat of bare ground as present in the late twentieth and early twenty-first century on the bridleways, tracks and footpaths to either too much trampling or to hard surfacing it is essential that alternative bare patches are created by either hand or mechanical digger excavation. A regular programme of creation, as a part of any lowland heath's management plan enables these patches and also the associated turf and spoil banks to become the new centres of the bare ground habitat providing our wasps and bees with future nest homes.

ABOVE: Typical nest holes of solitary bees and wasps situated in the bare ground of the tracks which are frequently overlooked by site managers' seemingly ignorant of this biodiversity which they are killing unnecessarily by entombing with hard surfacing, just to serve the leisure interests of the human species of animal. © Copyright SMiles.

ABOVE: Part of a hand excavated bare patch dug by the website promoter with the landowner and Natural England's permission on a heathland Site of Special Scientific Interest at Aldershot, Hampshire, a part of the Thames Basin Heaths' European Special Protection Area. This patch was excavated in February 2008 specifically to help the Mottled Bee-fly as mitigation for bare ground track habitats lost to hard surfacing for military vehicle use. © Copyright SMiles.

The retention of sand and earth banks, sand cliffs and sand-pits in the countryside

Wherever soil banks, containing bare sand, loam or clay occur in open, sun-exposed situations they need to be retained as a microhabitat that can be exploited by our nesting solitary bees and wasps. Sadly where these occur as a result of poaching of the soil surface on verges, by cars on narrow roads squeezing past each other, even here highway authorities have a tendency to hard surface the resultant earth patches. Sand or clay pits are also important sites for our nesting bees and wasps especially where vertical cliffs result from the excavations as these often have a different fauna from those locations where such soil exposures are on the flat. Important sites in Surrey have sadly been lost to development in the last ten years, they should not be seen as sites just suitable for refuse dumps or housing development. Especially on heathland, sandpits are very important in providing nesting situations for numerous species of solitary bees and wasps and their parasitoids.

ABOVE: Nest holes with the excavated soil still present of solitary bees and wasps in a vertical cliff sand-cutting in Hogmoor Inclosure, Bordon possibly threatened by landscaping to convert this ex-military training area into a Site of Alternative Natural Greenspace (SANG). © Copyright SMiles.

Further reading and references, some of which are referred to in the text above.

1 - A Code of Practice for the Management of Heathland Paths and Tracks, 2009, by S Miles, privately distributed by the author.

2 - Heathland Harvest - The Uses of Heathland Plants Through the Ages by Chris Howkins and published by the author in 1997 in England.

3 - Hymenoptera Aculeata in Surrey, by K M Guichard, published in the Entomologist's Gazette Volume 28, No 4 in 1977.

4 - Lowland Heathland SSSIs: Guidance on conservation objectives setting and condition monitoring by Alonso, I (et al). English Nature Research Report Number 511, published by English Nature (now Natural England) in 2003. (Based on Common Standards Monitoring guidance originally produced by the Lowland Heathland Lead Agency Group of the JNCC).

5 - The Common Lands of Hampshire by L E Tavener published by Hampshire County Council in 1957.

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