Wildlife Trust Derbyshire Wildlife Trust
East Mill, Bridge Foot, Belper, Derbyshire, DE56 1XH
Tel: 01773 881188 Fax: 01773 821826
E-mail: enquiries@derbyshirewt.co.uk

Da Vinci Community College Ponds

Da Vinci College



Derbyshire Wildlife Trust
East Mill
Bridgefoot
Belper
Derbyshire
DE56 1XH
A report for the Wild About Ponds Project
Prepared by Trevor Taylor
Local Wildlife Sites Officer (Planning)
Derbyshire Wildlife Trust

November 2010

Protecting Wildlife for the future

Regisered charity no. 222212
DWT is a company registered in England and Wales
with the Company Number 715675

Da Vinci Community College Ponds

Background

Derbyshire Wildlife Trust was commissioned to survey the two ponds located within the Da Vinci Community College Nature Area as part of the Wild About Ponds Project in order to provide management recommendations based upon the findings of the survey. It would also enable a comparison of survey results against data obtained as part of the 2004/5 Derby City Pond Survey.

Map 1 shows the location of the ponds. Two ponds are located within the Da Vinci Community College Nature Area (known as The Newt Pond). The site is a designated Local Wildlife Site DE023 and is registered on the Derby City Wildlife Alert Map.

Da Vinci Community College is a PFI (Private Finance Initiative) school with Norwest Holst contracted to build the new school and manage the project. As a PFI school the City Council have leased the school site to Norwest Holst for 25 years after which it will revert back to Derby City Council.

The north and east boundaries and some of the south boundary to the site is formed by steel security fencing. The west boundary is formed by hedge and temporary Herris fencing and part of the south boundary is formed by hedge. Access is only possible via a locked ornamental pedestrian gate in the west boundary. There is no access wide enough for vehicles.

Due to the need to ensure the safety and general welfare of the students the site is not suitable for open access to the general public and the boundary fencing and locked gate prevent unauthorised access.

The ponds are surrounded by a variety of habitat types including neutral grassland (species rich, damp and species poor rough), Bramble scrub, plantation woodland and hedgerows.

The two ponds within the site are distinctly different. The larger pond on the eastern side of the site is shown on Ordnance Survey First Edition maps dated 1882 and would therefore appear to be of some local historic interest. The smaller pond on the west side is more recent in origin and is thought to have been created around 1990. and includes a small central island. The western pond is seasonal in nature and regularly dries out during the summer months which, unlike the eastern pond, has prevented the establishment of a fish population. The shallow nature of the pond is such that much of the pond is dominated by emergent vegetation.

Survey objectives

The aim of the survey was to gather ecological information using the PSYM methodology in order to determinethe overall ecological quality of the pond and inform management recommendations to enhance the biodiversity value.

Methodology

The survey followed the standard survey methodology known as PSYM developed by Pond Action (now Pond Conservation) and the Environment Agency. PSYM, the Predictive System for Multimetrics, (pronounced sim) was developed to provide a standard method for assessing the biological qualities of still waters in England and Wales.

The method uses a number of aquatic plant and invertebrate measures (known as metrics) which are combined together and fed into a computer model, along with basic environmental and location data, to obtain a single value which represents the waterbody’s overall quality status.

The following information was gathered for the pond:

Calculating the pond metrics

The data collected from the surveys are used to calculate three plant metrics and three invertebrate metrics.

1. Number of submerged and emergent plant species

This is simply the number of submerged plant species plus the number of emergent plant species. The calculation does not include the number of floating-leaved species present. This is because the pond data suggest that the number of floating-leaved plants occurring at a site does not decline significantly with increasing degradation. The metric is therefore improved by omitting this plant group.

2. Trophic Ranking Score (TRS)

TRS is a measure of the average trophic rank for the pond. This is calculated by assigning each plant species with a trophic score based on its affinity to waters of a particular nutrient status. The trophic scores vary between 2.5 (dystrophic, i.e. very nutrient poor conditions) and eutrophic, i.e. nutrient rich conditions).

Unfortunately, not all plants have trophic scores. This situation has arisen because the current TRS values for standing waters (Palmer et al., 1992) are based only on analysis of lake data, and many plant species which are common in ponds occurred at too low a frequency in lakes to give them a score. Also, some plant species exhibit little nutrient preference.

The TRS value for a site is calculated as follows:

  1. The trophic scores from each plant species present at the site are summed together.
  2. The summed score is divided by the total number of plant species which have a trophic ranking score to give the TRS.
3. Uncommon Species Index

Uncommon species are those which have a rarity score of 2 or more. The number of these species is simply summed to give the number of uncommon species.

Uncommon species refers to species which can be best described as "local", "nationally scarce" or "Red Data Book". The rarity status values for Scarce and Red Data Book species are based on existing definitions derived from the Red data Books and other authorities. The definition of "local" has been used to define species which are not uniformly common and widespread in Britain: with plants this refers specifically to species recorded from between 100 and 700 10 x 10 km squares in England, Wales and Scotland.

4. Average Score per Taxon (ASPT)

The ASPT is calculated by summing the BMWP scores for all taxa present at the site and dividing by the total number of BMWP taxa present.

BMWP (Biological Monitoring Working Party) scores are assigned to taxa depending on their known tolerance to organic pollution, a higher score indicating lower tolerance. The scores were defined by Maitland in 1977.

5. Number of dragonfly and alderfly families.

This metric is the sum of the number of dragonfly (Odonata) and alderfly (Megaloptera) families.

6. Number of beetle families

This metric is the sum of the number of beetle (Coleoptera) families present at the site. The metric has a relationshipwith bank quality as well as water quality.

Results

The pond was surveyed using the PSYM methodology enabling an assessment of its biological quality to be made together with a comparison with other ponds in the area.

The PSYM scores are placed in four categories which reflect the ecological quality of the pond:

0-25% is very poor, 26-50% is poor, 51-75% is fair, and 76-100% is good

Da Vinci Pond West

Site and sample details

Grid reference: SK 37459 38362

Site Name: Da Vinci West

Location: Da Vinci Community College, Chaddesden

Owner/site access details: Derby City Council

Survey Date: 10th June 2010Surveyors: Trevor Taylor (Derbyshire Wildlife Trust)
Vanessa Amaral-Rogers
Alison Martin

During the site visit undertaken on 10th August 2010 the pond was totally dry and, as such, it was not possible to undertake a PSYM survey. A survey of aquatic plants was undertaken upon which it was possible to make management recommendations.

The PSYM survey details for the site visit undertaken as part of the 2004/5 Derby City Pond Survey are reproduced below:

Survey Date: 11th August 2004Surveyor: Trevor Taylor

Environmental Data

Altitude: (m)96m aslpH:8.32
Shade: % pond overhung:3%% emergent plant cover85%
Inflow (absent = 0, present = 1):0Pond area (m2)294m2
% of pond margin grazed:0

Pond base: categories into one of three groups; 1=0%-32%, 2=33%-66%, 3=67%-100%)

Clay/silt:1Sand, gravel, cobbles:3Bed rock:1
Peat1Other1

Emergent plants Rarity Score Trophic Ranking Score
 
Alisma plantago-aquqtica, Water-plantain19
Cardamine pratensis, Cuckooflower 1 -
Glyceria fluitans, Floating Sweet-grass 1 -
Iris pseudoacorus, Yellow Iris 1 -
Juncus articulatus, Jointed Rush 1 -
Juncus effusus, Soft rush1-
Juncus inflexus, Hard Rush1-
Sparganium erectum, Branched Bur-reed18.5
Typha latifolia, Bulrush18.5
 
Submerged plants
 
Ranunculus, aquatilis, Common Water Crowfoot210

Number of emergent and submerged species – 10
Number of uncommon species (with a rarity score of 2 or more) – 1

Trophic Ranking Score – 9.00

Macroinvertebrates
Group 2 taxa (BMWP:8)
Libellulidae (Dragonfly, Common Darter, Sympetrum striolatum)

Macroinvertebrates
Group 5 taxa (BMWP:5)
Nepidae - Water bug (Water scorpion)
Corixidae - Water bug (water boatman)
Hydrophilidae - Water beetle (scavenger)

Macroinvertebrates
Group 6 taxa (BMWP:4)
Baetidae - Mayfly

Macroinvertebrates
Group 7 taxa (BMWP:3)
Planorbidae - Ramshorn snail
Sphaeridae - Pea Mussel
Hirundinae - Leech, Horse Leech, Haemopsis sangusiuga)

Macroinvertebrates
Group 8 taxa (BMWP:2)
Chironomidae - Fly (non biting midge)

Macroinvertebrates
Group 9 taxa (BMWP:1)
Oligochaetae - True worm

Total No. Of taxa10
Total BMWP Score39
ASPT43.9
No. OM taxa1
No. Coleopt taxa1

Index of Biotic Integrity (PSYM Score %) = 50. As such the pond would be considered to be in poor ecological condition.

During pond dipping sessions undertaken in May 2006 good numbers of cased caddis of the family Limnephilidae and diving beetles of the family Dytiscidae were netted. This would result in an increase of the PSYM score during 2006 to 61% thereby placing the pond in the fair ecological quality category.

Da Vinci College

Above: Da Vinci West in 2005

Da Vinci College

Above: Da Vinci West in 2010

Survey results

The pond is considered to be a seasonal temporary pond which regularly dries out during the summer months. Noticeable features of the pond include the presence of a large population of Horse Leech, Haemopsis sangisuga together with good numbers of the Common Darter dragonfly Sympetrum striolatum.

During survey visits undertaken in 2004/5 it was noted that the pond contained much litter and debris as demonstrated in the above photograph. This was subsequently removed by a number of work parties facilitated by WildDerby and delivered by the school and Groundwork. Following the installation of security fencing, as part of the PFI school contract, incidents of abuse and litter have been much reduced.

Amphibian surveys undertaken in 2004 and 2005 identified the pond to support good numbers of Smooth Newt, Common Frog and Common Toad. On 3rd May 2005 a bottle trapping exercise caught 25 male smooth newts and 7 female smooth newts.

Da Vinci College

The pond is largely dominated by emergent aquatic vegetation with frequent Branched Bur-reed, Sparganium erectum and Yellow Iris, Iris pseudacorus. A small population of Common Water-crowfoot occurs in the eastern part of the pond

Left: Branched Bur-reed

Da Vinci College

Above: Common Water Crowfoot

A number of willows of varying ages have colonised the pond.

Recommendations

The surveys have identified that the dominance of emergent aquatic vegetation has resulted in the presence of little open water within the pond. The shallow nature of the pond, the dominance of emergent vegetation and the presence of colonising willow trees also accelerates the drying out of the pond particularly during hot, dry summer periods.

It is therefore recommended that some removal of emergent vegetation (Branched Bur-reed, Yellow Iris and Typha) is carried out in order to achieve open water up to approximately one-third of the total pond area. The vegetation removal, including the willow trees, should be undertaken during autumn/early winter when the majority of amphibians will have left the water. Great care should be taken to avoid the areas containing Common Water-crowfoot which is present in the eastern half of the pond. All removed material should be left on the margin of the pond for a few days to allow any invertebrates to return to the water. The removed material should then be composted on site at agreed identified locations to provide additional amphibian/reptile habitat.

Any rubbish/litter should be removed at the same time.

Annual PSYM surveys should be undertaken during the period June to August to monitor the ecological condition of the pond. The results would give some indication of management success and the need for further emergent vegetation removal. The results of the surveys should be forwarded to Derby City Pond Wardens Association and the Derbyshire Wildlife Trust.

Da Vinci Pond East

Site and sample details

Grid reference: SK 37562 38391

Site Name: Da Vinci East

Location: Da Vinci Community College, Chaddesden

Owner/site access details: Derby City Council

Survey Date: 10th August 2010Surveyors: Trevor Taylor (Derbyshire Wildlife Trust)
Vanessa Amaral-Rodgers
Alison Martin

Environmental Data

Altitude: (m)102m aslpH:7.39
Shade: % pond overhung:30%% emergent plant cover60%
Inflow (absent = 0, present = 1):0Pond area (m2)452m2
% of pond margin grazed:0

Pond base: categories into one of three groups; 1=0%-32%, 2=33%-66%, 3=67%-100%)

Clay/silt:1Sand, gravel, cobbles:3Bed rock:1
Peat1Other1

Emergent plants Rarity Score Trophic Ranking Score
 
Alisma plantago-aquqtica, Water-plantain19
Cardamine pratensis, Cuckooflower 1 -
Deschampsia caespitose, Tufted Hair-grass 1 -
Epilobium hirsutum, Great Willowherb1 -
Glyceria Fluitans, Floating Sweet-grass 1 -
Iris pseudoacorus, Yellow Iris1-
Juncus effusus, Soft rush1-
Juncus inflexus, Hard Rush1-
Solanum dulcamara, Bittersweet1-
Sparganium erectum, Branched Bur-reed18.5
Typha latifolia, Bulrush18.5
 
Floating leaved plants
 
Lemna minor, Common Duckweed19

Number of emergent and submerged species – 11
Number of uncommon species (with a rarity score of 2 or more) – 0

Trophic Ranking Score – 9.00

Macroinvertebrates
Group 2 taxa (BMWP:8)
Aeshnidae (Dragonfly, Southern Hawker, Aeshna cyanea)

Group 5 taxa (BMWP:5)
Gerridae - Water bug (Water skater)
Hydrometridae - water bug (Water measurer)
Corixidae - Water bug (Water boatman)
Hygrobiidae - Water beetle (Screech beetle)

Group 6 taxa (BMWP:4)
Baetidae - Mayfly

Group 7 taxa (BMWP:3)
Lymnaeidae - Snail (Lymnaea peregra)
Planorbidae - Ramshorn snail

Group 8 taxa (BMWP:2)
Chironomidae - Fly (non biting midge)

Group 9 taxa (BMWP:1)
Oligochaetae - True worm

Total No. Of taxa10
Total BMWP Score41
ASPT4.1
No. OM taxa1
No. Coleopt taxa1

Index of Biotic Integrity (PSYM Score %) = 44. As such the pond would be considered to be in poor ecological condition.

The previous PSYM survey undertaken on 16th August 2004 also returned score of 44% indicating that the pond has remained in poor condition for a number of years.

Da Vinci college

Above: Da Vinci East in 2004

Da Vinci college

Above: Da Vinci East in 2010


Survey Results

The pond is of some historic interest and is shown on the First Edition Ordnance Survey Maps dating from 1882. Unfortunately, the site has been subject to much abuse and dumping of rubbish over recent years. During a site visit in 2004, the pond was found to be very overshaded by mature willows and much dumping of rubbish, including oil drums, was evident. It was even reputed that a vehicle had been deposited in the pond.

During 2005 and 2006, as part of the PFI contract, much work was undertaken to clear the debris from the pond. The work was facilitated by WildDerby and delivered by Groundwork and the school and also included the pollarding of surrounding mature willows.

The reduction in shade has resulted in a slight increase in emergent vegetation which largely comprises Branched Bur-reed and Bulrush with occasional Yellow Iris. Evidence of young willows growing in the pond was noted. A noticeable feature of the pond is the presence of a large population of Three-spined Stickleback which presumably limits the macroinvertebrate interest. Amphibian surveys undertaken in 2004 and 2005 recorded Smooth Newt and Common Frog.

During the 2010 survey, evidence of debris was still present along with a surface film of oil which is likely to be a remnant from its past abuse.

Recommendations

The current extent of open water should be maintained by the removal of Branched Bur-reed and Bulrush on an annual basis during autumn/early winter with the aim of achieving up to one third of the pond area as open water.

All removed material should be left on the margin of the pond for a few days to allow any invertebrates to return to the water. The removed material should then be composted on site at agreed identified locations to provide additional amphibian/reptile habitat.

The young willows growing in the pond should also be removed and attempts should also be made to clear any debris and rubbish from within the pond.

Further pollarding of surrounding willows should also be undertaken.

Annual PSYM surveys should be carried out during the period June to August to monitor the ecological condition of the pond. The results would give some indication of management success. The results of the surveys should be forwarded to Derby City Pond Wardens Association and the Derbyshire Wildlife Trust.

Da Vinci College Map