Do agri-environment schemes benefit bats and their insect prey?

Transcription

1 Do agri-environment schemes benefit bats and their insect prey? Elisa Fuentes-Montemayor Dr. Kirsty Park Prof. Dave Goulson

2 Agricultural intensification and expansion: INTRODUCTION 76% of UK is agricultural land! Conventional farming practices Negative effects on biodiversity Bat populations

3 Agri-environment (AE) schemes: INTRODUCTION Financial incentives for farmers to adopt environmentally friendly agricultural practices 45% of agricultural land in UK UK Rural Development Programme billion to support sustainable agriculture Benefits to biodiversity? Contrasting results Benefits to bats?

4 Bats: INTRODUCTION Population decline during 20th century 16 species in UK, 9 in Scotland: Pipistrellus pipistrellus, P. pygmaeus, P. nathusi, Myotis daubentonii, M. nattereri, M. mystacinus, Nyctalus noctula, N. leisleri, Plecotus auritus. Insectivorous (Diptera, Trichoptera, Lepidoptera)

5 What for? Do AES benefit bat populations and insects? Which prescriptions are more useful for foraging bats and insects? Recommendations for AES Conservation of bats

6 Methods: METHODS Site selection Central Scotland Rural Stewardship Scheme 2004 Paired site design: 18 pairs AE vs. conventional farms Within 8 km of each other Same farming activities Similar size Field sites (pairs of farms)

7 Methods: METHODS AE farms had at least 4 types of prescriptions Habitat features relevant for insects and bats Compare with conventional farms Prescriptions in AE farms Field margins / beetle banks Hedgerows Water margins Species rich grasslands Equivalent features in conventional farms Unmanaged field margins Unmanaged hedgerows Unmanaged water margins Grassland / arable fields

8 Beetle bank vs. field margin METHODS

9 Hedgerows METHODS

10 Water margins METHODS

11 Species-rich grassland vs. pastoral field METHODS

12 Surveys and samplings: METHODS 1 pair of farms was surveyed during the same night during summer Bat activity was assessed with a bat detector. Transects ( km) incorporated AE prescriptions or equivalent features. Nocturnal insects were collected using moth traps, which were set at each prescription / feature at dusk and left for 4 hours.

13 METHODS Data analysis: Insects: abundance and id Bats: sound analysis, assign passes to prescriptions: FM WM HR Legend: Transect surveyed with bat detector Bats FM Field margin SRG HR WM SRG Hedgerow Water margin Species rich grassland Landscape analysis Statistics: generalized linear mixed effects models (using R)

14 Landscape analysis: METHODS What scale is more appropriate to assess the effects of the surrounding landscape on bats?

15 Landscape analysis: METHODS What scale is more appropriate to assess the effects of the surrounding landscape on bats? 250 m

16 Landscape analysis: METHODS What scale is more appropriate to assess the effects of the surrounding landscape on bats? 500 m

17 Landscape analysis What scale is more appropriate?

18 Landscape analysis: METHODS What scale is more appropriate to assess the effects of the surrounding landscape on bats? Does it depend on the mobility of the species? Buffer sizes from 250 m to 3 km around each transect.

19 Landscape analysis: METHODS OS MasterMap Topography Layer data (Digimap Ordnance Survey Collection) ArcGIS 9.2 Classify land in 5 categories: Urban (buildings & roads) Farmland Water Natural environment (rough grassland & scrub) Woodland Fragstats 3.3 to compute landscape metrics: For each land type (e.g. proximity between patches) For the whole landscape (e.g. heterogeneity index)

20 Landscape analysis: METHODS

21 250 m Landscape analysis: METHODS Urban Farmland Water Natural Woodland

22 500 m Landscape analysis: METHODS Urban Farmland Water Natural Woodland

23 1000 m Landscape analysis: METHODS Urban Farmland Water Natural Woodland

24 RESULTS Results food availability 15,000 nocturnal insects collected: Diptera (68%) Lepidoptera (19%) Trichoptera (10%) Coleoptera (1%) Hymenoptera (1%) Hemiptera (1%) Macros excluded for further analyses Micros only 4%

25 Food availability RESULTS Agri-environmental Conventional 500 Insect abundance per habitat Insect abundance per habitat: Fitted values - Insect abundance Field margin Hedgerow Grassland Water margin

26 RESULTS Bats Bat activity recorded at 95% of sites 2000 bat passes 6 species identified: Pipistrellus pipistrellus Pipistrellus pygmaeus Plecotus auritus Myotis daubentonii Myotis nattereri Nyctalus noctula

27 RESULTS Bats Agri-environmental Conventional P. pygmaeus per habitat 25 Fitted values - P. pygmaeus passes Field margin Hedgerow Grassland Water margin

28 RESULTS Bats Agri-environmental Conventional 8 P. pipistrellus per habitat Fitted values - P. pipistrellus passes Field margin Hedgerow Grassland Water margin

29 RESULTS Bats vs. food availability p < 0.001, z = 4.86 p < 0.001, z = 4.97

30 Bats vs. landscape RESULTS

31 Bats vs. landscape RESULTS

32 Summary SUMMARY Higher insect abundance at conventional farms No significant difference in biomass. Negative correlation bat activity insect biomass. Higher bat activity levels at conventional farms (except AE field margins). Surrounding landscape: P. pygmaeus and P. pipistrellus very different. Landscape important even at 3 km scale (management implications) Woodland very important! Promote creation and management for bats.

33 Acknowledgments Land owners Scottish Government People s Trust for Endangered Species CONACyT Liam Cavin Bob Dawson Lucy Dockray Emma Heskey Gillian Lye Víctor Peredo Jennifer Smith Rosie Trodden Mario Vallejo-Marín Rhona Webster

34 Thank you!