Wildlife
Wildlife and habitats are important aspects of quality of life, as plants and animals maintain ecological niches that collectively sustain the natural environment. Although much of Hertfordshire is a managed environment, natural processes do still operate and must be protected in order to maintain biodiversity.
Progress towards delivering biodiversity continued during 2005 with a number of important initiatives. These included managing the increasing pressure from development and changes in land use. The Government has published updated Guidance on Nature Conservation (PPS9) which supports non statutory sites and the need for information on wildlife. New Regional Spatial Strategies will place great pressure on county wildlife particularly around the M11 corridor, Luton Airport and Milton Keynes. Work continues to secure biodiversity conservation wherever possible, for instance there are new agrienvironment schemes which are targeted on the best wildlife areas.
Hertfordshire Biodiversity Action Plan Update
A county Biodiversity Officer was appointed in April 2005 to continue the biodiversity action planning process in Hertfordshire. The post is supported by both the Biodiversity Partnership and a Steering Group consisting of HEF supported by English Nature, the Environment Agency, Herts Biological Records Centre and Herts & Middlesex Wildlife Trust. The Partnership participated in the 3rd National Biodiversity Reporting Round, conducted online using the Biodiversity Action Reporting System (BARS).
The habitat and species working groups have now completed the review of their respective action plans (HAPs and SAPs). In pursuit of implementing actions within the Wetlands HAP, Herts and Middlesex Wildlife Trust has been successful in securing funding which enabled new reedbeds to be created at Rye Meads and Hilfield Park Reservoir and shorelines to be enhanced at Amwell Quarry Nature Reserve. Both projects will benefit a wide range of plants, animals and invertebrates. As part of the Farmland HAP, a community approach to the survey and recording of hedgerows on a Parish basis has been piloted by the Countryside Management Service (CMS) and a method for recording hedgerow lost from the county has been established. The Woodland group has prepared a project for mapping wood pasture and parkland and supported the open day at Broxbourne Woods National Nature Reserve. The Orchard HAP, implemented by the Herts Orchard Initiative (HOI), has helped to collect fruit from a number of orchards in East Herts for apple juice. HOI also co-ordinated 3 community fruit picking days and 6 highly successful Apple Day events across the County.
The Bittern SAP working group ran a co-ordinated roost watch monitoring programme through the winter months recording Bittern numbers at a number of sites. Evening tape-playing surveys for the Stone Curlew were conducted for the third year but sadly were unsuccessful in locating any birds and will not be carried out in the future. The action plan will now concentrate on creating nesting habitat for the birds on farms in north Herts through the Environmental Stewardship scheme. A field survey of all the known historical sites of River Water-dropwort was completed and records plotted onto the HBRC GIS system.
Indicator WH1 - Water voles
Water voles are thought to be Britain's most rapidly declining mammal and are now extinct in many rivers across the country. During the 1990s national surveys revealed that more than 90% of water voles disappeared in just a few years. Agricultural intensification and river management have degraded bankside habitats, whilst predation by the introduced American mink, against which water voles have no defence, has accelerated the decline of this vulnerable species.
The Hertfordshire Water Vole Project has carried out surveys in 2004 and 2005 along 40kms of rivers, ditches and lake banks. Overall 16% of sites had signs of water vole activity with strongholds remaining on the River Chess, River Mimram, River Purwell and parts of the Lea Valley. American mink have also been recorded on all main rivers in Hertfordshire during this period.
Indicator WH2 - Birds
The British Trust for Ornithology's Breeding Birds Survey (BBS) provides data on bird population changes from between 70-80 BBS plots surveyed in Hertfordshire every year. Four key indicator species have been chosen to reflect the quality of particular habitats or land-use types in Hertfordshire. The following is from the 2004 BBS report and the 2002 Hertfordshire Bird Report.
Grey heron (indicative of wetlands).
Grey herons breed in colonies and their nests are counted annually. Nationally, the grey heron is on the Green List of birds of conservation concern. In England, its population remained stable (1994- 2004), but numbers have declined in the Eastern Region (GOR5) by 28% (1994-2004). In Hertfordshire, breeding was recorded at just two sites: Amwell Gravel Pit (15 nests) and Verulamium Park (18 nests). Breeding also occurred at Stocker's Lake and Wilstone Reservoir, but no detailed counts of the number of nests were made.
Skylark (indicative of farmland)
is a national Biodiversity Action Plan species. Nationally, skylarks are on the Red List of birds of conservation concern. In England numbers declined by 19% (1994-2004), they also declined by 22% in the Eastern Region during the same period. In Hertfordshire numbers decreased by 8% (2000-2002).
Song thrush (indicative of woodlands and mixed, farmland)
is a national Biodiversity Action Plan species. Although widespread, song thrush remains on the national Red List of birds of conservation concern. In England numbers increased by 11% (1994-2004), but, in the Eastern Region, declined by 25% (1994-2004). In Hertfordshire numbers have increased by 23% (2000-2002).
House sparrow (indicative of the urban environment).
House sparrows are classified as a national Red List species. In England numbers have declined by 10% (1994-2004). Regionally, the species declined by 20% (1994-2004). However, in Hertfordshire, numbers increased by 1% in (2000-2002).
Indicator WH3 - Wildlife Sites
Wildlife Sites are the most important places for wildlife outside of nationally protected land such as SSSI's and are key to achieving biodiversity conservation in the wider countryside. Together with statutory sites and nature reserves, Wildlife Sites are a major part of the county's natural assets and play a vital role within the county Biodiversity Action Plan. There is now (Dec 2004) a total of 1975 Hertfordshire Wildlife Sites covering just 10% (approx) of the county.
| District | No.of WS | Total no.of sites notified | Percentage notified |
|---|---|---|---|
| Broxbourne | 94 | 65 | 69 |
| Dacorum | 242 | 209 | 86 |
| East Herts | 597 | 445 | 74 |
| Hertsmere | 124 | 96 | 80 |
| North Herts | 343 | 274 | 80 |
| St Albans | 197 | 145 | 74 |
| Stevenage | 41 | 35 | 75 |
| Three Rivers | 149 | 110 | 74 |
| Watford | 32 | 21 | 65 |
| Welwyn Hatfield | 206 | 166 | 81 |
| Total | 1975 | 1566 | 79 |
Note: Some Wildlife Sites occur across district boundaries and appear in counts for both districts. The total figure given is for the County.
Wildlife Sites are vulnerable to change and so monitoring is essential. This year a team of volunteer surveyors carried out 31 botanical surveys across the county. By Dec 2004, from this and other up-to-date information 10 new sites were added to the Wildlife Sites Register while 5 were removed, 2 to development and 3 to degradation. Given information about where Wildlife Sites are and why they are important, owners, planners and conservation bodies can work together to make informed decisions about the future of these sites and protect the county's Biodiversity. The Hertfordshire Wildlife Sites Partnership is coordinated by the Wildlife Sites Officer and consists of a number of conservation and farming organisations. 79% of sites have now been recorded to their owners and conservation advice to support /secure appropriate management continues to be provided by members of the partnership. Effective protection of Wildlife Sites is also achieved through the planning system. Over 232 planning applications affecting Wildlife Sites have been assessed/responded to by the partnership.
Indicator WH4 - Bats
It is no longer realistically possible to report back on the Pipistrelle bat indicator, so accessible data from bat hibernation counts in Hertfordshire are now to be used as a 'new' indicator. Some bat species move to underground hibernation sites during the winter months and since the 1990's licensed members of the Hertfordshire and Middlesex Bat Group have been monitoring the numbers of bats using these sites. A minimum of ten sites have been monitored on a regular basis since 1997, and data from these has been extracted to show the annual population trend from 1997 to 2004. Bats are counted in January and February and the total number recorded each year for all sites is shown in the table below. Numbers of Natterer's bats (a Hertfordshire Biodiversity Action Plan species) are also shown. Five species have been recorded from the hibernation sites since 1997. Natterer's are the most numerous (48%) followed by Daubenton's bat (41%), brown long-eared bat (10%), with Pipistrelle and Whiskered/Brandt's bat representing less than 1%. From 1997 to 2001, apart from a drop in 1998, there has been an increase in the total number of bats. Post 2001 however there appears to be a steady decline approaching 1998 levels.
Bat Hibernation Site Annual Counts (total 10 sites)
Bat counts
Source: HCC - download and view this data in excel
Indicator WH5 - Butterflies
Chalk grassland. Chalkhill Blue.
This very local species continues to live a charmed life on the chalk where its foodplant (Horseshoe vetch) is found, particularly Hexton Chalk Pit and Therfield Heath. The transect returns show long term stability and recent increases (18% up in 2004), but ultimately this species is always going to be limited by its foodplant which itself is localised and declining. If suitable sites, for example fields near Hexton Chalk Pit and Telegraph Hill, could be seeded then it is likely that the species would colonise and hopefully become more secure.
Neutral grassland/damp meadows.
Gatekeeper butterflies are doing well, with a 44% increase in numbers; the Meadow Brown has declined 23% this year but is still our most frequently-seen species. The Common Blue has a sadder tale to tell, with a 53% decline in 2004. Although still widespread, there has been a steady contraction in range from 84% of squares in the early 1980s to 63% in 1995-9 and 47% 2000-2004. This is presumably due to increasing loss of its foodplants by scrub encroachment or habitat degradation.
Acid grassland/heath/bracken.
There are signs of hope for the beleaguered Small Heath butterfly, with both an increase and an expansion for the second year running. However, the overall picture 2000-4 is not good, with continued losses and a thinner distribution compared to 1999. There is a hint from the data that the species is changing from universally common, as it was until the mid-1970s, to a species which is now really quite local. The Small Copper has dropped 41% this year, but is not as bad is it looked a couple of years ago, as its range has increased slightly.
Mature broad-leaved woodland.
The White Admiral butterfly experienced one of its best years numerically since the mid 1990s. Numbers were well up at Bricket Wood and Balls Wood, and about the same at Northaw Great Wood, so overall it has recovered from the low numbers of 2001-2003. Things have gone well for the Purple Hairstreak this year, with an increase in abundance and range, but it has still lost ground compared to 1995-9, particularly in southern Hertfordshire. Butterfly Conservation has just produced a leaflet on Woodland Management for Butterflies, in the hope of raising awareness among woodland owners and managers.
Rides and glades.
The Speckled Wood butterfly was down in numbers this year, but it has lost none of the ground gained in the great eastward movement of 1985-1999, and continues to be widespread. The Ringlet has also suffered a hopefully temporary setback, but despite this, the overall picture in the past five years is of continuing gains in ground and increasing numbers. An unexpected development has been the arrival of the Silver-Washed Fritillary butterfly in the county, with three sightings in 2003 and 25 sightings at 10 different sites in 2004. Though numbers were down in 2005, there is still hope that this species, which became extinct as a breeding species in Hertfordshire in the 1980s, may re-establish itself.
Scrub / hedgerows.
There has been very little change in numbers or range of the Brimstone, and the distribution is almost the same as five years ago. The Orange Tip butterfly fared extremely well in 2004, and showed an increase in range. The abundance in 2004 was almost the same as that in 1995.
The fortunes of our rare national BAP species of conservation importance show more cause for concern. A further drop in numbers of Grizzled Skipper this year highlights the precarious status if this species, and the data leaves little doubt that the position has worsened in the past five years. Lack of coppicing and regular canopy gaps in woodland, plus the decline in wildfires are held to be responsible. In our own area, Waterford Pit might typify what has happened. An excellent habitat in 1995 when it was wasteland with colonising vegetation, however with the best of intentions it has declined in value due to subsequent landscaping, tree planting, re-seeding and general tidying-up. More serious is the fate of the Small Blue. Hertfordshire's only known colony is almost certainly now extinct, with one caterpillar recorded in 2003, and nothing at all in 2004 and 2005. Only singletons of Green Hairstreak Butterfly were seen at 2 sites in 2004, after a long term loss of habitat, and there is little doubt that this species is in serious trouble in our area. It requires a short sward on chalk grassland, but on the other hand it also needs shrubs, especially Hawthorn, at low density to act as perches for male territorial behavior. The Purple Emperor is a much more encouraging story, and it is now known to be present at several sites in the south and west of the county, and new colonies have been found every year since 1999.
Indicator WH6 - Condition of SSSI's
Sites of Special Scientific Interest receive statutory protection for their biological or geological interest. Within Hertfordshire, 66% (by area) are considered to be in generally favourable condition. However, in terms of individual units assessed (by number), 100% of the open water units were considered favourable, but only 39% of grasslands and 52% of woodlands were favourable, the rest of these habitats being in an unfavourable class. This reflects the difficulties of achieving appropriate management. Livestock farming has declined and suitable grazing animals and graziers are increasingly hard to find, whilst the economics of forestry and the increasing damage caused by deer do not support or encourage appropriate woodland management. These broader issues affect management of the wider countryside as much as protected sites and reflect a larger problem which must be addressed if the quality of our best wildlife sites is to be maintained.