The Status and Distribution of Great Crested Newts Triturus cristatus in Worcestershire 2000

By Will Watson

Like most counties only casual records of great crested newts Triturus cristatus existed before 1986. However, these showed it to be widespread throughout the Worcestershire with records coming from Malvern in the west, Hopwood Dingle in the north and Corse Lawn in the south. In 1986 the National Amphibian Survey organised by Leicester Polytechnic was launched with funding from the Nature Conservancy Council. In 1987, Will Watson and Phil Williams conducted a blanket amphibian survey of the Warndon Parish in Worcester City; 410ha of biodiverse rural landscape scheduled for development. Forty five ponds were present and great crested newts were found in 12 of them in the first year. The ponds were studied over the 10 year period of the development recording great crested newts from 25 of the Warndon Ponds. The pond at Lyppard Grange, with 187 individual adult crested newts recorded in one evening, is still the best recorded site in Worcestershire.

Mainly from the mid 1990’s onwards I focused my attention on other parts of the county to find out if this high rate of occurrence was part of a pattern experienced elsewhere. Over a 14 year period of surveying (between 1987 and 2000 inclusive) I surveyed 387 ponds at least once for amphibians. Approximately half of the work conducted has been voluntary basis with the remainder of work being carried out from requests for amphibian data from a range a range of different organisations. Last year for example I was commissioned by the Environment Agency to survey 50 ponds in the county, I also undertook the survey of 28 ponds as Project Consultant for the County Council’s pond project Aqua Vitae 21.

A total of 335 of those ponds contained one or more species of amphibians, representing 86% of the total. An impressive 190 of those ponds surveyed contained Great Crested Newts. This is a 49% occurrence rate for this species. About 90% of the surveys carried out were targeted at all 5 common species and involved a minimum of 10 minute sampling either using netting or torching. Only about 10% of survey work carried out involved just egg searching and would be bias towards smooth and great crested newts.

This year have I attempted to focus on the areas where there is a high rate of occurrence for crested newts, usually coinciding with areas where there are clusters of ponds. By deliberately focusing on areas of known high occupancies one comes up with even more exceptional statistics. The survey of the National Trust estate at Hanbury Hall involved sampling 26 ponds (mostly, by egg search). Presence of great crested newts was found in 21 of these ponds within just 1.5km2. This was not a one off result for Worcestershire. Smaller surveys of pond clusters have revealed a similar rates of occupancy. These sites with high pond density supported by good terrestrial connectivity are by definition crested newt meta-populations.

The next and probably the most exciting phase of work will focus on carrying out evaluation on pond clusters where great crested newts are known to occur. This work will involve the recording of adult newts, during the breeding period using the most appropriate method according to the conditions. Sites which have been thoroughly surveyed on such a basis will be worthy of consideration for non-statutory wildlife site, SSSI or SAC designation.

Site designations alone will not protect ponds. Many of the ponds surveyed revealed that population sizes were low. In Warndon a fifth of ponds surveyed over the 10 year period revealed no signs of breeding at all. In a similar number of those ponds breeding only occurs wet seasons. This is believed to be typical for other parts of the county. What is also needed are financial incentives to manage ponds according to the best pond practices.

In terms of the biodiversity action plan establishing 20 new colonies within a county which on current evidence contains 2000 to 3000 great crested newt ponds is relatively insignificant objective and will not in itself lessen the rate of the extinction of local populations or the overall decline in population size. It is far more beneficial, in terms of species conservation, to encourage the natural expansion of the species in target areas and facilitate habitat management by restoring old ponds create new ponds and enhance existing amphibian corridors. Our next challenge is how to achieve such grand objectives under the local great crested newt species action plan.

What is required is strategic plan. Restoration work must carried out holistically to cater for also for macrophytes and macro-invertebrates. This process must work with the co-operation of landowners and where ever possible involve local communities. The Pond Warden Scheme operated in Cheshire and Lancashire is an excellent model to follow. But these schemes do not come cheap. Until we gear ourselves up to large scale restoration projects small -scale restoration maybe the most viable option in the short-term. We may achieve at least part of our objectives through Farm Plans tailor made for enhancing pond corridors as part of Countryside Stewardship agreements.

What has intrigued me for a long while is why some landscapes support large populations of great crested newts and others do not. We have known for a long while that there is strong correlation between pond density and great crested newt occurrence, but there is more to it than that. Worcestershire is not the mostly densely populated county for ponds. The county covers an area of 1735km2, there are approximately 5000 ponds covering less than 2ha in area within the county (derived by looking at recent Ordnance Survey maps). The average pond density in Worcestershire is 2.9 per 1km2. Both Cheshire and Suffolk have far more ponds. But Suffolk does not have anything like the same rate of occupancy by crested newts. However, part of Cheshire might equal rates of occupancy to Worcestershire. There is a common thread. The Cheshire plain is a clayland landscape predominated by Mercia Mudstone. The Severn Basin and Avon valley is also a clayland landscape. In Worcestershire as a whole Mercia Mudstone occupies about 40% of the county and Lower Lias clays about 20%. The greatest density of ponds are on the Mercia Mudstone. This substrate is contains bands of Tea-green Marl. Pond pH is usually to the basic side of neutral. Great crested newts are best suited to ponds which are slightly alkaline.

Worcestershire survey results

Worcestershire covers an area of 1735km2
There are approximately 5000 ponds covering less than 2ha in area within the county. (This figure was derived by looking at recent Ordnance Survey maps).
Average pond density in Worcestershire is 2.9 per 1km2.
387 ponds have been surveyed at least once for amphibians.
Approximately 7.7% of the total number of ponds within the county have been surveyed for amphibians.
190 of those ponds surveyed contained Great Crested Newts
This is a 49% occurrence rate for this species.
Based on these results there may be 2500 Great Crested Newt ponds in Worcestershire.
This would work out to be 1.44 Crested Newt ponds per kilometre across the whole county.
In 1916 there were 7653 ponds less than 2ha in size, comparing these results with today’s figures, we have lost at least 30% of our pond resource in the last 100 years.

Table 1 Occurrence of amphibian species by ponds in Worcestershire between 1987 and 1999. Numbers of ponds surveyed 386

Species present:
Great Crested Newt18950%
Palmate Newt103%
Smooth Newt21355%
Common Frog14838%
Common Toad4810%
Marsh Frog20.6%

The vast majority of the amphibian work was carried out be Will Watson, (herpetologist and West Midlands Regional Representative for HGBI) between 1987 and 1999. Most of these records were gathered in the last 3 years and 40% of all records were gathered last year. Fifty ponds were surveyed as a result of a survey commissioned by the Environment Agency and 28 through the Aqua Vitae 21 pond restoration initiative.
It is difficult to make direct comparison with surveys conducted in other counties. For a start very few counties have such a widespread series of records. However, this work indicates that there is an extremely high rate of occurrence for Great Crested Newts within Worcestershire ( Jim Foster: English Nature). It is possible to compare these results with a similar survey conducted in Cheshire by the Pond Life Project.

Table 2 Percentage occurrence of amphibian species in ponds by District in Worcestershire between 1987 and 1999

Species presentWychavonMalvern HillsWorcester CityRedditchBromsgroveWyeForest
Crested Newt62%52%33%46%28%44%
Palmate Newt0.9%8.3%6.4%11%
Smooth Newt60%62%53%80%26%33%
Common Frog30%46%54%69%50%22%
Common Toad12.5%36%5.8%38%6.4%22%
Marsh Frog0.9%1.4%
Nos. of ponds surveyed159728927349

There are several parts of the county which contain pond clusters where average pond density is over 6 per 1km2. This includes in the north-east of Bromsgrove District covering 8km2 and Bentley Pauncefoot in Bromsgrove. Other parts of county with similar pond density are Hanbury in Wychavon and Warndon Parish in Worcester City. The latter Parish contains 50 ponds within 4.1 km2.
All high pond density is on the so called ‘clayland’ landscape of the Mercia Mudstone which occupies about 40% of the land area of Worcestershire. Elsewhere on the Mercia Mudstone ‘claylands’ average pond density is between 3 and 6 ponds per 1km2. This landscape is well represented in Wychavon District, Malvern Hills District, Worcester City and Redditch Borough.
There is a good correlation between the rate of occurrence of Great Crested Newts and the distribution of ponds on the ‘clayland’ landscape. Over half of the ponds on the Mercia Mudstone were found to contain Great Crested Newts. In Warndon Parish for example 24 of the 50 ponds present were found to support Crested Newts. This figure would be much higher if one excludes the ephemeral ponds and permanent water-bodies containing fish. In Hanbury Parish, Wychavon District, 32 ponds have been surveyed and 26 of these have been found to contain Crested Newts.
Lower Lias deposits, where clay frequently outcrops cover about 20% of the county. However, pond density is much lower, usually averaging between 2 and 3 ponds per 1km2. High rates of occurrence for Great Crested Newts were also found on this substrate with the species being found in approximately 50% of all ponds surveyed.

Comparison with a survey in Cheshire

Cheshire covers an area of 2328km2
There are approximately 16000 ponds in Cheshire. (This figure was derived by studying Ordnance Survey maps, carrying out ground based field surveys and by looking at aerial photographs).
Average pond density is 6.9 per 1km2
ponds were surveyed for amphibians.
of those ponds contained Great Crested Newts.
This is a 31% occurrence rate for this species.
Based on these figures there may be 4960 Great Crested Newt sites in Cheshire.representing across the county an average occurrence of 2.13 Great crested Newt sites per 1km2.
In the 1870’s it was estimated that were 80,000 ponds in Cheshire, comparing these results with current figures it is estimated that 61% of ponds have been lost since that date.
This work was carried out by the Pond Life Project in 1995.

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