The effectiveness of reptile exclusion techniques as revealed by photorecognition Dr Liam Russell CEcol MCIEEM (Russell Ecology & ARC Ecological Services Ltd) Jim Foster MCIEEM (ARC Ecological Services Ltd & Amphibian and Reptile Conservation Trust) CIEEM Autumn Conference, Manchester, 21-22 November 2017
Outline Introduction Evidence & implications Your views
Introduction: Removal & exclusion in reptile mitigation Conventional approach: Active capture ( depletion) and exclusion
Disadvantages of conventional approach: Time-consuming Expensive Fence installation harm?
An alternative approach? No capture No fencing Instead: Habitat manipulation encourage reptiles to vacate and stay out of the development footprint Passive removal or displacement
Adjacent receptor site: Depletion and exclusion by habitat manipulation No fence, no capture Non-adjacent receptor site: Depletion by capture Exclusion by distance & habitat manipulation Fenced non-adjacent receptor site: Depletion by capture Exclusion by fence (& distance) (Conventional approach)
Natural England, In Practice 93 (2016)
Is there any evidence for the effectiveness of these new approaches? Studying how individual reptiles behave in these mitigation interventions can help build an evidence base. Over to Liam to talk about our experience
Individual photorecognition for reptiles It s easy! (for some species ) Track individual reptiles Assess numbers during survey Monitor capture success Monitor behaviour during mitigation Post-mitigation monitoring
Sand lizards: dorsal markings
Field photos no capture Breeding on receptor site 9 June 2016 Captured as a juvenile 9 June 2015 Recorded on receptor site 10 August 2017
Adders: Head and Neck Scale irregularities
Smooth snakes: Head and Neck
Grass snakes: upper ventrals
Common lizard and slow worm More difficult Less distinct markings Often large numbers Differences in numbers of labials Patterns on back and side of head not always distinct Throat scalation ventral spot pattern in males
I 3 S (www.reijns.com/i3s/index.html) Computer programmes Various versions could be applied to all species Needs uniform photos (no use for field photos) Requires hand annotation of identifying features Extract Compare (conservationresearch.org.uk/home/extractcompare/index.html) Specific versions for adder and sand lizard Works on photos from all angles Requires hand annotation of photos
Application in Mitigation Projects
Case study 1: Surrey woodland site Photorecognition very useful Take photos of all life stages No information on new animals entering the site Sand lizards can be very determined to get home Sand lizards can disperse through short vegetation Habitat manipulation can be effective but needs to be extremely thorough Possible risk of injury
Case study 2: Dorset quarry (1) 29 Male (18 recaptures) 29 Female (17 recaptures) 51 Immature (17 recaptures) 49 Hatchlings (0 recaptures) Open-ended fencing easily breached Habitat manipulation ineffective Lizards entering the site not just homing using breeding sites
Case study 3: Coastal site Homing ability in sand lizards by far exceeds documented distances 585m compared to 150m (Strijbosch et al 1983) Possibly due to shape of territory? Open-ended fencing not effective
Case study 4: Dorset quarry (2) Habitat manipulation not effective at causing sand lizards to move Even apparently secure fences can be breached Once an individual learns how to breach a fence it will remember! Breaches of fencing not limited to homing animals Fence breached to reach breeding place
Interactive session Advantages and disadvantages of these new approaches? Split into sub-groups Discuss, and use proforma to note findings - 20 minutes Report key conclusions at end of breakout session
Interactive session We are very interested to hear of your experiences, particularly if you have data you can share If you are undertaking any reptile translocations in the coming season and want to employ any of these techniques, please let us know liam@russellecology.co.uk jim.foster@arc-trust.org