Barbastelle Bats as a flagship species in landscape ecology

Graeme Lyons (summarising work by Frank Greenaway and Rich Howorth)

Photographs © Frank Greenaway

• Rare (Near Threatened), BAP and

heavily protected

• Complex ecology enables them to

act as an effective indicator of habitat

quality at the scale of the West Weald

landscape

Barbastelle Bat - a flagship species for landscape conservation

Barbastella barbastellus

Ferengi

• Roost in old-growth woodland with abundant damage & decay

Barbastelle Bat ecology

Barbastelle Bat ecology

• Forage for nocturnal flying insects (including micro-moths) in wetland fringes, damp grasslands & wet woodlands

• Bats studied since 1990s at Ebernoe Common SAC

Barbastelle Bat ecology

Long-term study

Flightline connectivity

• Commutes out along linear flight lines of woodlands, dense hedgerows and wooded river courses• Aversion to large gaps close to roost woods evident

Ecological Networks of Ebernoe Barbastelles

(1998)

Blue - good flightline

Red - unsuitable flightline habitat (break in cover)

Yellow - historic route,

no longer used

Barbastelle Bat flightlines from Ebernoe:

Barbastelle research

- Methods

• Studies at both The Mens and Ebernoe Common SACs in 2008:a new baseline survey and re-survey after 10 years respectively

• Individual Barbastelle Bats were sequentially caught and ringed

• Selected breeding females were radio-tagged and tracked to identify roosts, flightlines and forage areas • Roost counts were also made at the time of evening emergence to assess colony size & structure

• Point data, directly derived from field bearings and observations.

• Ranging data. Computer-generated Minimum Convex Polygons (MCPs).

• Foraging data. Computer-generated 50% activity forage-area kernels.

Barbastelle research

- Data & Analysis

41 Barbastelles trapped, 18 tagged

17 tree roosts identified

Population minimum of 80 females

At least 4 different sub groups

8 flightlines – all to the East

50%-activity forage-area kernels

averaged 31% of the MCP area

Results for the Mens SAC

Barbastelles of The Mens SAC

55 Barbastelles trapped, 20 tagged

27 tree roosts identified

Population minimum of 64 females

At least 3 different sub groups

6 flightlines – varying directions

50%-activity forage-area kernels

averaged 23% of the MCP area

Results for Ebernoe Common SAC

Barbastelles of Ebernoe Common SAC

The Mens

Ebernoe

Landscape Overview

Results – MCPs & Forage Kernels

• Travelled shorter distances.• Ranged over smaller areas.• Used smaller forage areas.

At Ebernoe Common in 2008 there were twice as many Barbastelles as 10 years earlier, but they:

Results – Ebernoe Forage Areas

1998 vs. 2008

Mean characteristics of Barbastelle populations for The Mens SAC (2008) and Ebernoe Common SAC

(2008 re-survey and 1998-99 original survey)

Max distancetravelled (& range)

(km)

50% forage kernel

area (& range) (ha)

Total MCP ranging activity area (&

range) (ha)

Minimum number of breeding

female bats

The Mens 2008(n = 18)

7.1(2.6-12.2)

379.8(61.3-1152.2)

1235.7(260.2-2928.0)

80

Ebernoe 2008 (n = 20)

5.2(1.2-10.5)

178.2(20.9-368.3)

779.5(45.1-2521.0)

64

Ebernoe 1998-1999 (n = 19)

7.1(4.5-17.8)

325.9(14.4-1146.0)

1243.9(41.2-4575.3)

29

• Estimated population is 200 & 250 bats at Ebernoe and The

Mens respectively.

•445 km2 covered by these.

• A strong dependence on woody flightlines.

• A seasonal dependence on exclusive forage areas.

• In 2008, Ebernoe Barbastelles showed more favourable

population characteristics than The Mens population.

•The reduced size and closer proximity of forage areas around

Ebernoe in 2008, indicates that insects are more locally available

Overview of Bat Research Findings

We can attribute the positive changes of the Ebernoe Barbastelle population over the last ten years to a combination of:

• New habitat creation nearby

• Less intensive land use

• Targeted reserve management

• Greater integrity of ecological corridors

Landscape improvements around Ebernoe

001Butcherland flightline structure and management.

• A mosaic of grassland and scrub developing on 60 ha of ex-arable fields since 2001, under an extensive grazing regime.

• Particularly beneficial to Barbastelles, as evidenced by the improved flightline cover and extensive commuting and foraging activity recorded there.

Butcherlands

2001Butcherlands 2001

2013Butcherlands 2013

Butcherlands 2005Butcherlands 2005

Butcherlands 2011Butcherlands 2011

2005Butcherlands 2005

2011Butcherlands 2011

• 1181.7 saplings/ha

• 52.2 hawthorns/ha

• 414.9 oaks/ha

• 25,000 oaks at Butcherlands!

Regeneration at Butcherlands

•The Barbastelle Bat serves as an excellent flagship species for landscape scale conservation.• Targeted conservation measures for Barbastelles are likely to benefit other wildlife.• Barbastelles also act as a good specific focal species for habitat condition and connectivity - spanning woodland, grassland and wetland BAP priority habitats.•The species is interesting, unusual and charismatic and draws funding and media attention.• However, caution should be used in using the Barbastelle as an ‘indicator species’ for other taxa, unless this is supported by a strong evidence base.• This research is helping to steer sensitive spatial planning through the Local Development Framework and can support WFD implementation. • A programme of further research and periodic monitoring is in place to support ongoing conservation enhancements to the ecological networks identified.

General Conclusions

Acknowledgements:

•Funding of bat research by BBC Wildlife Fund, Heritage Lottery Fund and Chichester District Council

•Bat licensing by Natural England

•Local Landowners for access and allowing ecological enhancements

•Frank Greenaway for all bat images

•Sussex Wildlife Trust for other images

•Sussex Biodiversity Record Centre for additional mapping