Version classiqueVersion mobile

What Works in Conservation 2021

 | 
William Junior Sutherland
, 
Lynn V. Dicks
, 
Silviu O. Petrovan
, 
et al.

2. Bat conservation

2.9 Threat: Pollution

Texte intégral

2.9.1 Domestic and urban waste water

Unknown effectiveness

Change effluent treatments of domestic and urban waste water

1One study evaluated the effects of different sewage treatments on the activity of foraging bats. The study was in the UK. We found no studies that evaluated the effects of changing effluent treatments of domestic and urban waste water discharged into rivers on bat populations.

2COMMUNITY RESPONSE (0 STUDIES)

3POPULATION RESPONSE (1 STUDY)

4Abundance (1 study): One replicated, site comparison study in the UK found higher activity (relative abundance) of foraging bats over filter bed sewage treatment works than over active sludge systems.

5BEHAVIOUR (0 STUDIES)

6Assessment: unknown effectiveness (effectiveness 25 %; certainty 20 %; harms 0 %).

https://www.conservationevidence.com/​actions/​1014

No evidence found (no assessment)

7We have captured no evidence for the following interventions:

  • Prevent pollution from sewage treatment facilities from entering watercourses

  • Reduce or prevent the use of septic systems near caves.

2.9.2 Agricultural and forestry effluents

Likely to be beneficial

Reduce pesticide, herbicide or fertiliser use

8Four studies evaluated the effects of reducing pesticide, herbicide and fertiliser use on bat populations. One study was in each of Mexico, Portugal, Germany and Columbia.

9COMMUNITY RESPONSE (3 STUDIES)

10Community composition (1 study): One replicated, site comparison study in Portugal found that farms using few or no chemicals had different compositions of bat species to farms using high chemical inputs.

11Richness/diversity (2 studies): One site comparison study in Mexico found that coffee agroforestry plantations using few or no chemicals had a higher diversity of insect-eating bat species than plantations with high chemical inputs, but the diversity of fruit and nectar-eating bat species did not differ. One paired sites study in Germany recorded more bat species over grassland with moderate or no fertiliser applications than grassland with high fertiliser applications.

12POPULATION RESPONSE (3 STUDIES)

13Abundance (2 studies): Two site comparison or paired sites studies (one replicated) in Portugal and Germany found that farms or grasslands with few or no chemical inputs had higher overall bat activity (relative abundance) than those using high chemical inputs.

14Condition (1 study): One replicated, site comparison study in Columbia found that great fruit-eating bats captured in ‘silvopastoral’ areas that used no chemicals, along with agroforestry, had higher body weights and body condition scores than those in conventional farming areas that used chemicals. BEHAVIOUR (0 STUDIES)

15Assessment: likely to be beneficial (effectiveness 77 %; certainty 60 %; harms 0 %).

https://www.conservationevidence.com/​actions/​2013

No evidence found (no assessment)

16We have captured no evidence for the following interventions:

  • Change effluent treatments used in agriculture and forestry

  • Introduce legislation to control the use of hazardous substances

  • Plant riparian buffer strips

  • Prevent pollution from agricultural land or forestry from entering watercourses

  • Use organic pest control instead of synthetic pesticides.

2.9.3 Light pollution

Beneficial

Leave bat roosts and roost entrances unlit

17Five studies evaluated the effects of leaving bat roosts and roost entrances unlit on bat populations. Two studies were in the UK, and one study was in each of Canada, Hungary and Sweden.

18COMMUNITY RESPONSE (0 STUDIES)

19POPULATION RESPONSE (2 STUDIES)

20Abundance (1 study): One replicated, controlled study in Canada found that numbers of big brown bats and little brown bats roosting in buildings increased when roosts were left unlit and decreased when roosts were illuminated with artificial lights.

21Condition (1 study): One replicated, controlled study in Hungary found that juvenile bats had a higher body mass and greater forearm length at unlit roosts than at roosts with artificial lighting.

22BEHAVIOUR (4 STUDIES)

23Use (1 study): One replicated, before-and-after study in Sweden found that all of 13 unlit churches continued to be used by brown long-eared bat colonies over 25 years, but bat colonies abandoned their roosts at 14 of 23 churches that were either partly or fully lit with floodlights.

24Behaviour change (3 studies): Three controlled studies (including two replicated studies) in the UK and Hungary found that more bats emerged, and bats emerged earlier and foraged for shorter periods, when roosts were left unlit than when they had artificial lighting.

25Assessment: beneficial (effectiveness 90 %; certainty 80 %; harms 0 %).

https://www.conservationevidence.com/​actions/​1017

Likely to be beneficial

Avoid illumination of bat commuting routes

26Three studies evaluated the effects of avoiding the illumination of bat commuting routes on bat populations. Two studies were in the UK and one was in the Netherlands.

27COMMUNITY RESPONSE (0 STUDIES)

28POPULATION RESPONSE (3 STUDIES)

29Abundance (3 studies): One replicated, before-and-after study in the Netherlands found similar numbers of pond bats flying along unlit canals and canals illuminated with lamps. Two replicated, controlled studies in the UK found greater activity (relative abundance) of lesser horseshoe bats and myotis bats along unlit hedges than along hedges illuminated with street lights, but activity was similar for common and soprano pipistrelles and Nyctalus/Eptesicus species along unlit and illuminated hedges.

30BEHAVIOUR (2 STUDIES)

31Behaviour change (2 studies): One replicated, before-and-after study in the Netherlands found that 28–96 % of pond bats changed their flight paths along canals to avoid light spill from lamps. One replicated, controlled study in the UK found that lesser horseshoe bats were active earlier along unlit hedges than along those illuminated with street lights.

32Assessment: likely to be beneficial (effectiveness 70 %; certainty 50 %; harms 0 %).

https://www.conservationevidence.com/​actions/​2017

Avoid illumination of bat foraging, drinking and swarming sites

33Two studies evaluated the effects of avoiding the illumination of bat drinking sites on bat populations. Both studies were in Italy and one was also in Israel. COMMUNITY RESPONSE (0 STUDIES)

34POPULATION RESPONSE (2 STUDIES)

35Abundance (2 studies): Two replicated before-and-after studies (one randomized) in Italy found that unlit water troughs had greater activity (relative abundance) of five of six bat species/species groups and six of eight bat species/species groups than troughs illuminated with artificial light. One of the studies also found that unlit desert ponds in Israel had greater activity (relative abundance) of three bat species than illuminated ponds.

36BEHAVIOUR (0 STUDIES)

37Assessment: likely to be beneficial (effectiveness 80 %; certainty 52 %; harms 0 %).

https://www.conservationevidence.com/​actions/​2018

Use low intensity lighting

38Three studies evaluated the effects of using low intensity lighting on bat populations. The three studies were in the UK.

39COMMUNITY RESPONSE (0 STUDIES)

40POPULATION RESPONSE (2 STUDIES)

41Abundance (2 studies): One replicated, randomized, controlled study in the UK found that activity (relative abundance) of lesser horseshoe bats, but not myotis bats, was higher along hedges with medium or low intensity lighting than hedges with high intensity lighting. One replicated, randomized, controlled study in the UK found that activity of myotis bats, but not common pipistrelles, was higher along treelined roads with street lights dimmed to an intensity of 25 % than roads with streetlights dimmed to 50 % or left undimmed.

42BEHAVIOUR (1 STUDY)

43Behaviour change (1 study): One replicated, controlled study in the UK found that more soprano pipistrelles emerged from two roosts when the intensity of red lights was reduced by placing filters over them.

44Assessment: likely to be beneficial (effectiveness 65 %; certainty 50 %; harms 5 %).

https://www.conservationevidence.com/​actions/​1018

Use red lighting rather than other lighting colours

45Three studies evaluated the effects of red lighting on bat populations. Two studies were in the Netherlands and one was in the UK.

46COMMUNITY RESPONSE (0 STUDIES)

47POPULATION RESPONSE (2 STUDIES)

48Abundance (2 studies): One replicated, controlled, site comparison study in the Netherlands found that red lighting resulted in higher activity (relative abundance) for one of three bat species groups than white or green lighting. One site comparison study in the Netherlands found that culverts illuminated with red light had similar activity of commuting Daubenton’s bats as culverts illuminated with white or green light.

49BEHAVIOUR (1 STUDY)

50Behaviour (1 study): One replicated, controlled study in the UK found that more soprano pipistrelles emerged from a roost when lit with red light than when lit with white light, but no difference was found between red and blue lights.

51Assessment: likely to be beneficial (effectiveness 50 %; certainty 50 %; harms 0 %).

https://www.conservationevidence.com/​actions/​2021

Unknown effectiveness

Restrict timing of lighting

52One study evaluated the effects of restricting the timing of lighting on bat populations. The study was in France.

53COMMUNITY RESPONSE (0 STUDIES)

54POPULATION RESPONSE (1 STUDY)

55Abundance (1 study): One replicated, paired sites study in France found that turning off streetlights for part of the night resulted in mixed results for activity (relative abundance), depending on bat species, when compared with leaving streetlights switched on all night.

56BEHAVIOUR (0 STUDIES)

57Assessment: unknown effectiveness (effectiveness 38 %; certainty 20 %; harms 0 %).

https://www.conservationevidence.com/​actions/​1019

Use ultraviolet filters on lights

58One study evaluated the effects of using ultraviolet filters on lights on bat populations. The study was in the UK.

59COMMUNITY RESPONSE (0 STUDIES)

60POPULATION RESPONSE (1 STUDY)

61Abundance (1 study): One randomized, replicated, controlled study in the UK found that hedges lit with ultraviolet filtered lights had higher soprano pipistrelle, but not common pipistrelle activity (relative abundance) than hedges lit with unfiltered light.

62BEHAVIOUR (0 STUDIES)

63Assessment: unknown effectiveness (effectiveness 45 %; certainty 22 %; harms 0 %).

https://www.conservationevidence.com/​actions/​1020

No evidence found (no assessment)

64We have captured no evidence for the following interventions:

  • Direct lighting away from bat access points or habitats

  • Use ’warm white’ rather than ’cool’ LED lights

  • Use glazing treatments to reduce light spill from inside lit buildings.

2.9.4 Timber treatments

Likely to be ineffective or harmful

Restrict timing of timber treatment application

65One study evaluated the effects of restricting the timing of timber treatment application on bat populations. The study was in the UK.

66COMMUNITY RESPONSE (0 STUDIES)

67POPULATION RESPONSE (1 STUDY)

68Survival (1 study): One replicated, controlled laboratory study in the UK found that treating timber with lindane and pentachlorophenol 14 months prior to exposure by bats increased survival but did not prevent death.

69BEHAVIOUR (0 STUDIES)

70Assessment: likely to be ineffective or harmful (effectiveness 5 %; certainty 55 %; harms 50 %).

https://www.conservationevidence.com/​actions/​1023

No evidence found (no assessment)

71We have captured no evidence for the following interventions:

72• Use mammal-safe timber treatments in roof spaces.

2.9.5 Industrial effluents

No evidence found (no assessment)

73We have captured no evidence for the following interventions:

74• Introduce or enforce legislation to prevent ponds and streams from being contaminated by toxins.

2.9.6 Noise pollution

No evidence found (no assessment)

75We have captured no evidence for the following interventions:

  • Impose noise limits in proximity to bat roosts and habitats

  • Install sound barriers in proximity to bat roosts and habitats.

CC-BY-4.0

Le texte seul est utilisable sous licence CC BY 4.0. Les autres éléments (illustrations, fichiers annexes importés) sont « Tous droits réservés », sauf mention contraire.

Acheter

Rechercher dans OpenEdition Search

Vous allez être redirigé vers OpenEdition Search