Wildlife
Biodiversity monitoring continues to reveal mixed fortunes for Hertfordshire’s wildlife
Water voles received extra legal protection in 2008 whilst bird indicators showed a decline in 2007 in the Eastern Region. Dragonfly fauna is rich but hare and butterfly numbers appear to be falling. SSSI condition continues to improve and Wildlife Site numbers remain stable.
Hertfordshire’s biodiversity resources remain under pressure despite the success of conservation initiatives. On one hand, agri-environment schemes and wildlife projects continue to deliver, support and raise the profile of wildlife. On the other, agricultural economics and extensive developments undermine sensitive land management, changing and fragmenting open land and habitats. Climate change places further environmental pressure on species as they are forced to adapt or they become threatened by non-native species and new diseases. Under these circumstances it is important to continue to understand what is happening to our wildlife and to make provisions for its conservation.1
Indicator WH1 - Water Voles2
Water vole
American mink
The Heritage Lottery Fund has financed a Wetlands for Water Voles and People Project which began in November 2007 and will guarantee future water vole conservation in Hertfordshire up to 2011. In the project’s first year, water vole surveys were carried out over 30km of wetland and river habitat. Of the sites surveyed, 19% showed signs of water vole presence with the rivers Mimram, Purwell, Lea and Chess maintaining their strongholds. The river Rhee also appeared to be supporting a good number. Control of the water vole’s main predator, the American Mink, has been maintained with reported sightings down in many areas from previous years. It is hoped that new legislation - see box - will make an impact on the protection of these species.
Indicator WH2 - Birds3
The British Trust for Ornithology (BTO) conducts a Breeding Birds Survey (BBS) which provides bird population data. In 2004 sixty-three 1km BBS squares were surveyed in Hertfordshire and four key indicator species were chosen to reflect the quality of particular habitats or land-use types in the county. The following data is derived from the BTO's 2006 BBS report and Hertfordshire Bird Club's2 2004 Hertfordshire Bird Report.
Grey Heron
Grey Heron
Grey herons breed in colonies and their nests are counted annually. A wetlands indicator, this bird is on the Green List of birds of conservation concern. Nationally its population increased by 12% (1994- 2007), but declined in the Eastern Region (GOR5) by 24% (1994-2007). In Hertfordshire, a total of 71 nests was recorded (113 were recorded in 2004).
Skylark
Skylark - Photograph: Tony Blake
Indicative of the condition of farmland, this national Biodiversity Action Plan species is on the national Red List of birds of conservation concern. Numbers declined by 21% (1994-2007) in England and by 29% in the Eastern Region (1994-2007). In the county numbers increased by 14% (2004-2005).
Song Thrush
Songthrush - Photograph: Tony Blake
Indicative of the condition of woodlands and mixed farmland, this national Biodiversity Action Plan species remains on the national Red List of birds of conservation concern. Although widespread, its numbers in England rose by 20% (1994-2007), but fell by 19% in the Eastern Region, (1994-2007). In the county numbers rose by 15% (2004-5).
House sparrow
House Sparrow
Indicative of the condition of the urban environment, House sparrows are classified as a national Red List species. In England, numbers declined by 18% (1994-2007). Regionally, the species declined by 33% (1994-2007). In Hertfordshire, the number of house sparrows recorded rose by 16% (2004-2005).
Indicator WH3 - Wildlife Sites4
Wildlife Sites, also known as Local Wildlife Sites, are the most important places for wildlife outside legally protected land such as Sites of Special Scientific Interest (SSSIs). Essential for biodiversity conservation, with statutory sites and nature reserves, they form a major part of the county’s natural assets and play a vital role in its Biodiversity Action Plan (BAP)9. Their identification assists site owners, planners and conservation bodies to make informed decisions to protect and maintain the county’s biodiversity. Latest research shows that by December 2007 there were 1,994 wildlife sites covering about 10% of the county. (New data is due May 2009). In 2007-8 over 337 planning applications, directly or indirectly affecting wildlife sites, were assessed or responded to by the Wildlife Sites Partnership. Volunteer surveyors carried out botanical surveys to assess the condition and status of 32 sites.
Indicator WH4 - Hares5 (replaces bat indicator)
Hare numbers are declining across the country. ©Gill Turner.
As bat data has not been available for some time, it was decided to replace this with data from a long term study of hare behaviour which has been taking place in the south east of Hertfordshire. Data produced over the last seven years can be used to show population trends. The countryside monitored includes mixed woodland with coppiced hornbeam, surrounded by grazing land, hay meadows and mixed arable land. Hares have always been most frequent in the arable areas and rare to absent elsewhere. Although 2004 was a good year for hares generally, since 2002 there has been a gradual decline within the study area. This is a disturbing trend for mixed countryside areas in Hertfordshire.
Source: Gill Turner & Hertfordshire Biological Records Centre, Hertfordshire County Council 2008
download and view this data in excel - disclaimer
Indicator WH5 - Butterflies4
Winter 2006-7 was very mild and a third of butterfly species appeared earlier than ever recorded in 2007, but the wet summer saw numbers of most species decline. Indeed, long term trend analysis over 18 years indicates that butterfly numbers were the lowest ever recorded in Hertfordshire, declining at twice the national rate. (This analysis is based on 7 butterfly transects with unbroken records since 1992; see graph below). Fluctuations are due to weather but butterfly numbers are down almost 2% per year in the county against the 1% per year for the same species nationally.
Whilst the warming trends of climate change may have been thought to benefit many species, the continued loss or degradation in the quality of their habitats, principally grasslands, could well be a major factor for butterfly and insect decline.
BAP9 species of conservation concern
Large Skipper
The Dingy Skipper, Grizzled Skipper and Green Hairstreak populations all fell by over 50% although these were more widespread. The Purple Emperor also declined and was seen at fewer sites.
Chalk grassland
Chalkhill Blue - Photograph: Tony Blake
The previously abundant Chalkhill Blue butterfly declined by 66% at Therfield Heath. This drop is thought to be partly due to over-grazing locally.
Neutral grassland/damp meadows
All grassland butterflies declined but the Marbled White continued to spread across the county, being found at 43% more sites in 2007 than 2006. The number of Small, Essex and Large Skippers declined substantially and their range retracted between 10% and 19%.
Annual average of sightings in transects taken in Hertfordshire
Source: Hertfordshire & Middlesex Butterfly Conservation November 2008
Note: Same percentage of same species used as for Hertfordshire. ie Comparing like with like.download and view this data in excel - disclaimer
Acid grassland/heath/bracken
Small Heath - Photograph: Tony Blake
Small Copper - Photograph: Tony Blake
Small Heath butterfly numbers declined by 25% and was lost from 12% of sites, whilst the Small Copper had a slight decline at 5% with no change in range.
Mature broad-leaved woodland
White Admiral numbers have fallen and range has declined, but at Bricket Wood there were signs of improvement due to woodland management.
Rides and Glades
Silver Washed Fritillary - Photograph: Tony Blake
White Letter Hairstreak - Photograph: Tony Blake
Speckled Wood butterflies are spreading steadily across the county, with a 4% rise in sites identified, despite numbers falling by 25%. The Silver-washed Fritillary, a species that returned to the county in 2004, rose 5% but was not so widespread. Purple and White-letter Hairstreaks declined considerably.
Scrub/hedgerows
Gatekeepers - Photograph: Tony Blake
Ringlet - Photograph: Tony Blake
Gatekeeper numbers fell by 38%, but their range increased by 6%. The Ringlet, however, declined in both number and range.
Indicator WH6 Condition of SSSIs7
43 sites in the county are designated to be of Special Scientific Interest (SSSI) for their national biological or geological interest and where management aims to maintain or enhance their value. Their condition is now a government indicator and sites are monitored to assess if they are favourable or unfavourable, improving or declining. A site classified as being in ‘favourable condition’ includes those in ‘favourable condition’ (36.6%) and those that are ‘unfavourable but recovering’ (51.09%). The SSSIs are divided into 119 recording units, 12 of which were visited during 2008. The condition figures are calculated using the sum of all visits in previous years and all have been visited in the last ten years.
SSSIs in a favourable condition*
| Year | 2004 | 2005 | 2006 | 2007 | 2008 |
|---|---|---|---|---|---|
| Percentage | 68% | 66% | 70% | 87% | 88% |
Source: Hertfordshire Biological Records November 2007
*favourable includes favourable but recovering by area
All aquatic habitats were in favourable condition, but terrestrial grassland and woodland habitats continue to be affected by challenges including encroachment by invasive plants, excess deer or rabbits, under or over grazing, nutrient enrichment, damage by vehicle and a lack of livestock or woodland management. Positive management can be supported by various agri-environment or forestry schemes. There was a slight change in improvement to ‘unfavourable but recovering’ classifications in Broadleaved Woodland habitats and an increase in the ‘favourable’ category of Standing Water.
Conditions of SSSIs
Source: Hertfordshire Biological Records Centre(Hertfordshire County Council) and Natural England December 2008
download and view this data in excel - disclaimer
New indicator WH7 Damselflies and Dragonflies8
These insects are one of the most efficiently recorded taxonomic groups in the UK. Situated between Hertford and Ware, King’s Meads is one of the best sites in the county for damselflies and dragonflies. It supports all of the county’s 19 breeding species and has been regularly monitored since 2003, results of which are summarised below. The continued variety in species reflects the site’s positive management.
Dragonfly species at Kings Meads 2003-7
| 2003 | 2004 | 2005 | 2006 | 2007 |
| 16 | 18 | 15 | 16 | 18 |
Source: A Reynolds and Hertfordshire Biological Records November 2008
The Blacktailed Skimmer dragonfly. Photo: Alan P Reynolds ©
Hertfordshire Biodiversity Action Plan Update9
Wetlands: Work to improve access and interpretation to wetland reserves has been undertaken, as has a project to audit Hertfordshire’s wet woodlands.
Orchards: Ten years of activity by Herts Orchard Initiative were celebrated by a launch at Shenley and eight other Apple Day events across the county.
Grasslands: A meeting for farmers was held with the Chilterns Area of Outstanding National Beauty to explore a wide range of issues affecting the livestock sector and conservation grazing.
Farmland: 6 applications for Higher Level Stewardship covering 2,250 hectares have been supported by the Countryside Management Service and specialist advisors. Other agri-environment schemes were supported by the Farming & Wildlife Advisory Group and Land Agents.
Urban: The draft Action plan was reviewed in June.
Bittern: Work to improve habitats for fish populations was undertaken to benefit Bitterns which feed on small fish. Nearly all reedbed management plans are focussed on benefiting Bitterns.
Tree Sparrow: Monitoring of the only breeding colony by the Hertfordshire Bird club has shown 2008 to be the best year recorded.
Stone-curlew: 8 nesting plots were successfully established over 26 hectares at 4 farms in the county.
Grizzled Skipper: 2008 was the best year for sightings of this species over the last 5 years. Waterford Pit has improved whilst other sites remained stable.
Purple Emperor: Numbers recorded in 2008 were very low, although reports from new sites in the west of the county suggest a presence in this area.
Wildlife Training: Herts & Middlesex Wildlife Trust, Hertfordshire Natural History Society and Lee Valley Regional Park ran ‘Learning about Wildlife’ workshops to encourage more people to become involved in recording the county’s biodiversity.
Biodiversity Action Reporting System (BARS): The Biodiversity Partnership contributed to the BARS data which helps to measure the UK’s progress towards the 2010 Biodiversity Target to reduce biodiversity loss.
Recent legislation and guidance10
National Indicator 197: Improved Local Biodiversity
As part of the UK Government’s objective to provide
‘A healthy, resilient, productive and diverse natural
environment’, this indicator has been created to
measure “Improved Local Biodiversity.” This will be
monitored annually as the “proportion of Local Sites
where positive conservation management has been or
is being implemented during the last 5 years.” Positive
conservation management is defined as “management
that maintains or enhances the features of interest for
which a site has been selected” and documented
evidence of appropriate management activities is
required. “Good performance” is indicated by an
increase in the percentage of sites under positive
conservation management year on year.
More protection for water voles
Water voles received further legal protection in April
2008. Fully protected under Section 9 of the Wildlife &
Countryside Act 1981, is it now an offence to:
- intentionally kill, injure or capture a water vole;
- possess or control a live or dead water vole, or any part of a water vole
- intentionally or recklessly damage, destroy or obstruct access to any structure or place which water vole use for shelter or protection or disturb water voles while they are using such a place;
- sell, offer for sale or advertise a live or dead water vole
The water vole is on the Government’s List of Species of Principal Importance for the Conservation of Biodiversity in England. An ecological appraisal, which may form part of a statutory Environmental Impact Assessment, is recommended for all developments where water voles may be affected. This will provide information regarding the level of impact and consider ways to reduce, avoid or remedy the impact.
Acknowledgements & Footnotes
This report was collated by Hertfordshire Biological Records Centre (HBRC) with additional information provided as shown
1 Martin Hicks, HBRC Tel: 01992 556158
2 Alison Washbrook, Wetlands for Water Voles & People Project ,
Herts & Middx Wildlife Trust (HMWT) Tel: 01727 858901 x231
3 Graham Goodall, HBRC Tel: 01992 556155
4 Anita Parry, HBRC, Carol Lodge, HMWT
5 Gill Turner, Martin Hicks c/o HBRC
6 Dr J Murray, Herts Natural History Society & Butterfly Conservation
(This is an analysis of actual 2007 data which was not previously
available and is the latest data available from our volunteers).
7 M Hicks, HBRC, Natural England County Statistics
8 M Hicks, HBRC, A Reynolds, Herts Dragonfly Group.
9 Catherine Wyatt, BAP Officer, Tel: 01279 655261
10 Martin Hicks HBRC, Alison Washbrook HMWT
Hertfordshire Biological Records Centre website: enquire.hertscc.gov.uk/hbrc
Herts & Middlesex Wildlife Trust website: /www.wildlifetrust.org.uk/herts/