Furesfen Boat Surveys
Bat Surveys by boat on the Lee Navigation 30.9.06–30.10.061.0 / Introduction
1.1 / Bat activity surveys were undertaken by boat on the evenings of 30.9.06 and 30.10.06, during narrowboat journeys from Old Ford Lock to Springfield Park and from Springfield Park to Stonebridge Locks, respectively. A surveyor, using Bat Box 4 Frequency Division equipment recorded: bat activity; position (using GPS) and light levels (using a light logging metre). Sound was recorded onto compact flash cards, which was subsequently analyzed through Bat Sound Software. Bats usually emerge about twenty minutes after sunset depending on the species, light levels, weather conditions and time of year. However in open river habitats, this is usually much later and recordings were made from thirty five minutes after sunset. Subsequent bat activity will last for about an hour and thirty minutes after sunset, during times of peak insect activity.
2.0 / Legislation and conservation measures
2.1 / · Bats are protected under European Law. This pertains to the bat and its roost or place of shelter.
· Planning Policy Statement 9 issued last year states that ‘LPA’s (Local Planning Authorities) must pay regard to any features which a Biodiversity Target Species (BAP) relies upon’.
· Natural Environment and Rural Communities, 2006 (NERC) states that ALL public bodies now have duty to conserve biodiversity.
· In addition Natural England (formerly English Nature) has jurisdiction on the buffer zone around Special Sites of Scientific Interest (SSSI) such as Walthamstow Marshes.
Land managed for nature conservation often attracts protected species to the local area including Hackney and Walthamstow Marshes which are very attractive to foraging bats.
All species of bat are fully protected under the Wildlife and Countryside Act 1981 (as amended) through their inclusion in Schedule 5. All bats are also included in Schedule 2 of the Conservation (Natural Habitats, & c.) Regulations, 1994. The Act and Regulations make it illegal to:
· intentionally or deliberately kill, injure or capture (take) bats;
· deliberately disturb bats (whether in a roost or not);
· damage, destroy or obstruct access to bat roosts;
· possess or transport a bat or any other part of a bat, unless acquired legally; or
· sell, barter or exchange bats or parts of bats.
If a bat roost is to be affected by development activities, a licence from the Department for the Environment, Food and Rural Affairs (DEFRA) will need to be obtained.
The Natural Environment and Rural Communities Bill, 2006 was given royal assent in March and became law on October 1st. It extends the Countryside and Rights of Way Act, 2000 (CROW Act) on the duty of public bodies and statutory undertakers to ensure due regard to the conservation of biodiversity.
3.0 / BRIEF RESULTS
3.1 / Six species of bat were recorded during the boat trips:
Common pipistrelle Pipistrellus pipistrellus
Soprano pipistrelle Pipistrellus pygmaeus
Nathusius’s Pipistrelle Pipistrellus nathusii
Daubenton’s Bat Myotis daubentoniiNatterer’s Bat Myotis natterii
Noctule Bat Nyctalus noctula
3.2 / Lighting levels were high on certain stretches especially by, Heron House, Watermint Quay and Leaside, a new boathouse (approaching the bend towards Springfield Park). Where light levels were exceptionally high, (as measured using a logging light metre) very little bat activity was recorded and usually in the form of a brief pass rather than prolonged feeding. Some pipistrelle and noctule activity was recorded in illuminated areas, but usually where levels were below 5 lux.
Natterer’s bats were recorded only in the darkest stretches of the navigation.
During the late autumn survey, which took place on 30.10.06, common pipistrelle bats were noted foraging around the railway bridge and at Markfield Park.
4.0 / Summary
4.1 / Of the six species recorded, four are of particular conservation interest.
Nathusius’s pipistrelle:
This species has not been recorded in this part of London until recently. It was found to be the dominant pipistrelle species along the Springfield Park stretches of the Navigation.
Noctule bats over Hackney Marshes:
Noctules are rare in London their status is under re-evaluation due to recording analysis highlighting their regular confusion with Leisler’s bats. During 2005 car surveys undertaken by the Herts. & Middx. Bat Group, only eight Noctule bats were recorded during 600 miles of travel. Noctule bats will exploit invertebrates attracted to lighting (including floodlit areas, author’s data, 2006). They are not however flying in the lit areas but above them. It is likely that Leisler’s bats are also present.
Natterer’s Bat:
This is a species only found in particularly low levels of lighting and conservation measures must be taken to ensure its persistence. It is a biodiversity target species in Hertfordshire due to concerns regarding its conservation status. Records of this species exist in few London Boroughs (London Biological Records Centre, 2006).
Daubenton’s Bat:
Daubenton’s bats are probably the most frequently encountered of the Myotis species in Britain. It is closely associated with water and is known for its habitat of foraging close to the surface of ponds and rivers which makes it easily visible. Nationwide it is thought to be a widespread species which is possibly increasing, although this trend has not been repeated in the London region where conservation measures should be taken to ensure favourable status.
There are a number of scheduled operations along the navigation which need to consider the needs of bats. These include the restoration of buildings, treeworks and other developments.
There are proposals to increase the lighting within Markfield Park as part of a Heritage Lottery Funded Project. Bat surveys should be undertaken prior to any works to determine how the proposed changes may affect this species. In any event there should be no light spillage onto the watercourse.
Table 1: To show time, bat species, speed and lux along the Lee Navigation 30.9.06
Time / Bat Species / LUX / Speed / Grid Ref19:21:37 / 2x Natterer's / 0.4 / TQ 37293 84498
19:27:27 / 2x Natterer's / 0.6 / 1km/h / TQ 37253 84500 Bridge near Hertford Union
19:30:43 / 45 pip / 1.4 / 3 km/h / TQ 37239 84638
19:31:18 / 45 pip / 0.3 / 2 km/h / TQ 37232 84661
19:54:22 / Leisler's/noctule / 2.7 / 3 km/h / TQ 36527 85691 Hackney Marsh
19:54:52 / Leisler's/noctule / 2.9 / 4 km/h / TQ 36518 85712
19:55:34 / Leisler's/noctule / 2.5 / 3 km/h / TQ 36499 85750
19:56:12 / Leisler's/noctule / 2.2 / 3 km/h / TQ 36479 85775
19:56:48 / Myotis / 4.8 / 3 km/h / TQ 36456 85799
19:57:24 / Myotis / 3 / 3 km/h / TQ 36434 85815
20:12:53 / 45 pip / 0 / 2 km/h / TQ 35906 86409
20:14:19 / 45 pip / 0 / 1km/h / TQ 35864 86432
20:15:07 / 45 pip / 0 / 2 km/h / TQ 35840 86443
20:17:40 / 55 pip / 0.1 / 3 km/h / TQ 35733 86484
20:18:08 / 55 pip x 3 / 0.4 / 4 km/h / TQ 35706 86488
20:18:42 / 55 pip / 1.1 / 4 km/h / TQ 35675 86499
20:37:24 / Natterer's x2 / 4.0 / 4 km/h / TQ 35128 87260 Many Natterer's before Leaside boathouse
20:43:07 / pip species / 0.7 / 3 km/h / TQ 34914 87527 13 lux at boathouse
20:46:06 / Natterer's x2 / 0.1 / 3 km/h / TQ 34764 87611
20:46:55 / 2xNathusius / 1.3 / 4 km/h / TQ 34739 87651
20:49:20 / 55 pip / 0.1 / 4 km/h / TQ 34645 87768
20:50:32 / 45 pip / 0.2 / 3 km/h / TQ 34629 87844
20:51:28 / Nathusius’s / 0 / 3 km/h / TQ 34614 87898
20:52:44 / Nathusius’s / 0.1 / 3 km/h / TQ 34591 87955
20:53:06 / Nathusius’s x2 / 0.2 / 2 km/h / TQ 34584 87972
20:53:58 / Nathusius’sx2 / 0.5 / 1km/h / TQ 34578 88002
20:55:19 / 55pip / TQ 34577 88002
n.b. This is a snapshot, late season survey, undertaken during the bat mating season. A different picture may emerge during the bat breeding season and increased activity and a greater diversity of species would be noted. It can be difficult to separate the calls of Leisler’s and Noctule bats during the autumn and it is likely that both species are present.
Caution is needed when reading lux levels as the position of the boat can be several metres away from the position of the bat and anomalies will occur. This is why it is important that the results are not considered separately from the experience of the surveyors. It has been noted, in the case of Daubenton’s bats on the non-tidal Thames (Fure & Wedd, 2006) that bats will use the shadow created by the hull of the boat to navigate through brightly lit bridges.