In Britain, 98% of our species-rich traditional grasslands have been lost since 1945, largely because they do not fit with modern farming practices. Consequently managing the remainder sustainably is difficult. Meadows need to be cut annually; a recent newspaper dispute relating to Heswall Fields has been over the date of that cut. Before the 1980s it would have been cut in July, the date varying with the weather and other farm activities. I have found 2 botanical surveys of the Fields, dating from 1984 and 2004. Both are done differently to the survey I was part of in 2011, but there is no evidence for a decline in plant species richness in the Fields.
The arguments about cutting date centre around the effects on bee and other insects of loss of nectar source. These animals are mobile, moving around the landscape to find food, using woods in spring, meadows in early summer, marshes and heathlands later on, and gardens all season. The clifftop field at Heswall Fields has much black knapweed, a late-flowering perennial not normally found in hay meadows. It is the cause of the perceived problem, as it is still flowering at hay-cut time, although most other plant species present have seeded by then. There is considerable visual impact to it being cut in flower, but the loss of nectar to the insects is relatively small, at a time when other habitats are providing forage.
There are two ways of sustaining the habitat by keeping the Fields mown as a hay crop. One is the existing farm tenancy, which gets the field cut and baled, but must be done while there is still food value in the hay crop, otherwise it is unusable and unsaleable. This means cutting sometime in July, depending on weather. Alternatively pay a contractor to do it, which is equally dependant on weather and machinery availability, and if done after the end July, as has been demanded by some people would also entail paying to dispose of the arisings to commercial composting, as they would be worthless as hay. This could cost at least £1000 per annum. I consider the latter would be unsustainable in financial terms, does not produce significant benefit to insects, and is not justified in environmental terms, as it would lead to waste and a greater carbon footprint.
So it is my opinion that a small loss of nectar/pollen forage in August, when there are plenty of other sources locally, is an acceptable price for sustainable management of this grassland habitat. We have to think long-term and in landscape terms if we are to sustain even our existing wildlife in the coming difficulties wrought by global climate change. See www.cheshirewildlifetrust.org.uk about Landscape-scale nature conservation.
For some scientific background to support the information above, the following may be of interest.
Heswall Fields and Other Hay Meadows:
Management Considerations
For a scholarly but accessible account of meadows in general, see George Peterken. (2013). Meadows. British Wildlife Publishing.
1. Hay meadows and other traditional species-rich grasslands are the habitat to have suffered most loss since 1945: at least 97%, rather more in Cheshire. The losses are mostly due to changes in farming practice: modern farmers make silage rather than hay, apply fertilisers to increase yield, and herbicides to control unwanted species. Remaining species-rich grasslands therefore have to be managed as exceptions to usual farming practice, or outside farming practice by mowing and removing the arisings. In traditional farming systems the aftermath would be grazed in autumn and sometimes early spring.
2. The date of the hay-cut has always varied depending on weather and the season. "When the yellow-rattle rattles, the hay is ready to cut" - referring to a once-common hay meadow plant. The balance is between the crop being mature enough to dry swiftly, and it still having good nutritional value. In Cheshire, the hay-cut was usually in mid to late July. However, weather was and is a problem: hay needs at least 5 days fine weather to cut, make and bale. We do not get 5 fine days together very often in this part of the world! So a farmer has always had to take advantage of whatever window of weather appeared. Farm tenancies have long specified a minimum date for hay-cut, and this is done for remaining hay meadows to prevent silage cutting: in Cheshire the usual date is July 1st, to allow a practical window for cuttings depending on weather and season. For some time in the 2000s, the then farm environmental support scheme (Countryside Stewardship) gave a payment towards hay-making which allowed a later date of 15th July to be set, with the payment making up for losses if the hay was not got in while still good as feed. The current stewardship rules (Environmental Stewardship) are different and do not allow single fields to be funded this way.
3. There are habitat surveys of Heswall Fields available for 1984 and 2004, both done for National Trust, the first in house, the second by contractors. A botanical species list was done by Wirral Wildlife surveyors in 2011. RECORD have supplied other data they hold, including a number of invertebrates. The various surveys are not directly comparable, but there is no evidence for a decline in species richness of the clifftop field over the last 30 years.
Neither of the two earlier surveys mentions the abundance of common or black knapweed (Centaurea nigra), which is now a feature of the clifftop field. Knapweed is not normally prominent in hay meadows, because it flowers in July-August and would set relatively little seed before the hay cut. There could be several reasons for its abundance at Heswall Fields.
If a recent phenomenon, then it could be due to acidification of the soil by rainfall and/or falling soil fertility, as knapweed is tolerant of both. The rain on Heswall Fields must be fairly clean, so not markedly acid, but also carrying little nitrogen or phosphate, unlike rain further inland. Traditional hay meadows were fertilised annually with farmyard manure (FYM), and the local ponds suggest the Heswall ones, like many in Wirral, were also periodically marled to lessen acidity. Artificial fertilisers at normal farm rates rapidly reduce species-richness by increasing the growth of a small number of highly competitive grasses and other species, including knapweed. However, on the clifftop field the hay crop is now very light, so much so that it must be barely worth the farmer's while to harvest it. It may be that he has not been applying FYM or lime because of the public access, and this over the years has led to dropping soil fertility.
If the knapweed abundance is long-standing, then it could indicate that the clifftop field was either managed as foggage (late summer grazing) or cut as bedding in late summer. Foggage is impractical on a public field with an open cliff edge, and bedding in an era of good road transport is much more easily and cheaply bought in as straw.
A difference in cutting date between July and August will not have significant effect on the plant composition of the field: at worst a mid-July cut might reduce the knapweed somewhat, but not completely as it will continue on the uncut margins and, as a long-lived perennial, from occasional years when the weather forces a late cut or occasionally none at all.
4. Invertebrate usage. The Fields are used by a range of flying invertebrates: systematic survey is lacking, but data from RECORD show that a range of wild bees, butterflies, hoverflies etc occur there. Species-rich clifftop grasslands in general are important for the solitary bees that nest in eroding cliff-faces. The cliffs along Heswall Fields are part of the Dee Cliffs SSSI, but invertebrate study has not been carried out in detail on this SSSI. Solitary bees mostly fly fairly early in the season.
All these flying invertebrates move round the landscape to find forage. Wood and hedges are good sources in spring; remaining species-rich grasslands in early summer; marshes and heathlands in late summer; and gardens all season. Early summer (June) has become the thinnest time in many landscapes, with the loss of traditional grasslands.
By the time the knapweed flowers on the clifftop grassland, most other species present have set seed - the one significant exception is wild carrot, which favours the clifftop edge, where it is not cut anyway for obvious reasons. There is also a wide margin left along some of the hedges where carrot and knapweed continue flowering. So some nectar sources are left when the hay is cut - but more importantly, by that time of year other nectar sources in the area, e.g. the headland at Heswall Dales and the saltmarsh on the Dee Estuary, are in full flower and providing alternative sources. So the loss of nectar/pollen when the field is cut is relatively minor and the flying insects will simply move elsewhere.
Since the aftermath is not grazed, there is in many years a degree of fresh flowering of various species in August-September, which provides some useful late nectar for species feeding up before hibernation e.g. Comma and Small Tortoiseshell butterflies. If the cut was later, this fresh flowering would be less.
5. To keep the Heswall Fields as species-rich grassland habitat they must be cut or grazed, otherwise they would turn into woodland. Grazing is impractical on a public site of this nature. The cut can be done by:
a) keeping the existing farm tenancy, which gets the field cut and baled, but must be done while there is still food value in the hay crop, otherwise it is unusable and unsaleable. This means cutting sometime in July, depending on weather. The cutting at this date entails a considerable visual effect by removing knapweed, and a small loss to foraging insects, but makes use of the hay for local feed and has minimal carbon footprint, being done by the local farmer.
b) pay a contractor to do it, which is only slightly less dependent on weather and machinery availability and, especially if done in late August to let the knapweed flower longer, would also entail paying to dispose of the arisings to commercial composting, as they would be worthless as hay: cost at least £1000 per annum. Also probably loss of the hay as feed, and a bigger carbon footprint as machinery has to travel to this isolated site.
I consider this second route would be unsustainable in financial terms, and is not justified in environmental terms, as a small loss of nectar/pollen at a non-critical time would lead to a waste of animal food and greater carbon footprint. So it is my opinion that a small loss of nectar/pollen forage in August, when there are plenty of other sources locally, is an acceptable price for sustainable management of this grassland habitat.
6. There may be some confusion with wildflower grasslands created in urban areas, for amenity and biodiversity benefits in the urban landscape. I have been involved with such habitat creation schemes for 35 years, and our biggest problem throughout that time is continuity of management. Urban sites cannot be grazed, nor usually mown for hay because of fire risks to the drying hay and contamination with dog faeces and litter. Getting the wildlife grassland cut in late summer is not always a problem, but there is great difficulty in getting the arisings taken off to prevent smothering and nutrient build-up, the latter gradually leading to competitive species taking over the sward. In practice, the cuttings are either left on, leading to decline in flowers (see Central Park, Wallasey), or the grassland is not cut at all, with rapid failure (Maher Park, Bebington), or the cuttings are taken off for a few years, but when money gets short the management fails (Bidston Moss landfill, managed by Forestry Commission). Similarly ask Ness Gardens or Woodland Trust (Upton Meadow) or Wirral BC (Arrowe Park) about the problems getting their hay meadows/wildflower grasslands cut. So a sustainable farming tenancy has a lot to recommend it in the long term.
7. We have to think long-term and in landscape terms if we are to sustain even our existing wildlife in the coming difficulties wrought by global climate change. The flying invertebrates need a whole landscape; large-scale farming support schemes and changes to urban land management are needed to put back wildflowers back into the landscape. Also much reduced and careful use of pesticides and fertilisers. Sustainable ways of doing this have to be continued or found, bearing in mind that money is likely to be in short supply for along time, perhaps indefinitely, as rising fuel prices continue. "Climate weirding" is already with us as climate change happens, making our weather even less predicable and activities that depend on it, like hay-making, harder to carry out. A sustainable farm tenancy has much to recommend it, and my main concern is that the public use of the field is inhibiting that management, and could be a long-term problem, especially as so few people understand the practicalities of grassland management.
Hilary Ash
.jpg)
