National Amphibian and Reptile Recording Scheme – NARRS Amphibian Surveys.
-
Upload
jessica-hibbard -
Category
Documents
-
view
229 -
download
0
Transcript of National Amphibian and Reptile Recording Scheme – NARRS Amphibian Surveys.
National Amphibian and Reptile Recording Scheme – NARRS
Amphibian Surveys
Aquatic habitat
Survey Methods
• Egg searching • Netting• Torching• Bottle trapping• Refuge searching• Pitfall trapping
Egg SearchingSubmerged vegetation
Great crested newt
Smooth/palmate newt
• Focus on newly-laid eggs• Harder to identify once larva takes shape
Egg Searching
Advantages Disadvantages
Quick method Little value for determining population size
Great crested newt eggs are distinctive
No equipment is needed
Low level disturbance
Netting
A good net with a rigid frame and a mesh of approximately 2-3mm costs around £50-60 including delivery
Netting Effort
• Work around the pond perimeter• Net along two-metre lengths of shoreline• Agitate the net through aquatic vegetation in two-
metre arc• Netting open water is less effective than netting in
vegetation
Great crested newt larva
Smooth newt larva
Overwintering larva
Netting
Advantages Disadvantages
Useful for catching great crested newt larvae and general sampling.
Needs a sturdy net.
Allows accurate identification. Often ineffective for adult great crested newts.
Long ‘season’ (March-October). Disturbance to pond.
Can be carried out during the daytime.
Risk of transfer of pest plants and possibly diseases.
Torching
• Newts primarily nocturnal
• Detects presence and allows a count
• Best time March-May
• Warm, still evenings (Avoid wind, rain, or low temperatures)
• Larvae detected late summer, early autumn
Torching
• Two- metre sections• The torch should be moved away from the bank
and back, to cover the area of the pond in the two- metre segment
• Repeat for all the accessible areas of the pond• Record the percentage of the perimeter surveyed• Daytime survey work should occur prior to
torching, so that any potential hazards can be identified in the daylight
Torching
• Size difference of GCN obvious, and male tail flash
• Count total newts seen
Torching
Brighter generally better. (e.g. 500,000 to 1,000,000 candlepower)
Good torch can cost £40-120e.g. Clubman CB1 or CB2
Torching
Advantages Disadvantages
Minimal disturbance to pond and newts
Has to be done after dark (safety & access issues)
Quick survey method Unsuitable in rainy and windy weather
Identification of species can be difficult from a distance
Difficult in murky and turbid ponds (e.g. after netting)
Bottle (or funnel) Trapping
• Typically used where torching is not possible
• Turbid water, too much vegetation, rain, wind
• More onerous and potentially dangerous than torching, netting etc.
Bottle Trapping – Welfare Issues
• March-April: 12 hours• May: 10 hours• June: 8 hours• July-August: 7 hours• Sept- October: 8 hours
Bottle Trapping
Advantages Disadvantages
Reliable method to detect adults and larvae
Risk of killing adults and larvae (and other species)
Useful technique in weedy or turbid ponds
Risk of vandalism/interference
Allows accurate identification Logistically onerous – You MUST be trained and experienced to use bottle trapping!
Keeps pond disturbance to a minimum
Stakes can puncture pond liners
Refuge searching
• Looking under rocks, logs, discarded debris – where moisture is retained
• March-October• A bit hit and miss• Supplementary technique only
Method J F M A M J J A S O N D
Bottle + ☻ ☻ ☻ + + ☻ L
☻ L
Egg + ☻ ☻ ☻ +
Torch + ☻ ☻ ☻ + + +L +L
Net + ☻ ☻ ☻ + + ☻ L
+L
Pitfall + ☻ ☻ ☻ + + + ☻ +
Refuge + ☻ ☻ ☻ ☻ ☻ ☻ +
+ = may be found/ less effective ☻ = optimal/ most effective L = larvae present
Fdsfgdgggdg
NARRS – pond selection
• A NARRS amphibian survey is conducted on a pond in a randomly-chosen square, usually within 5 km of the surveyor’s post code
• Important to have representative sample
Home
Locating the pond within your square
• Starting at the south-west corner of the square, find the nearest pond
• Can locate on map, but need to confirm in the field
Gaining access permission
Unless there are public rights of way, you must get permission from the landowner to visit the site and carry out the survey. You need to check that your mapped pond is still present, and that there are no other ponds closer to the south-west corner of the square.
• Knock on doors and ask locally
• Use access request letter (see www.narrs.org.uk)
Pond access
If there are no ponds within the survey square then move to one of the immediately neighbouring squares – start with the square to the north, then move clockwise
If a landowner is unwilling to grant permission for you to access the site, either move to a neighbouring square as above or request another square from ARC
Definition of ‘pond’
Water body between one square metre and two hectares, which holds water for at least four months of the year
How to carry out the pond survey
Your contact with the landowner is a good opportunity to find out some information about the pond, for example:
Has it been stocked with fish?
How often does it dry out?
Are there any safety issues, e.g. steep or slippery banks?
Is it known to support amphibians?
!Remember to prepare your risk assessment!
How to carry out the pond survey
NARRS amphibian surveys are conducted using the same methods we have practiced, but note also:
Breeding frogs and toads can be detected most easily during their peak spawning time
Frog- or toadspawn can be found
Techniques used for newts can also spot frog and toad tadpoles
Licensing
• Most widespread amphibians do NOT require a licence in order to carry out a survey - the exception is the great crested newt (and other EPS)
• If you are in an area where you’re likely to find GCNs, you should be licenced or accredited
• As a guide, if you find GCNs and are not licensed or accredited, you should stop surveying that pond and gain accreditation
• ARC can accredit people trained by ARC staff and/or if recommended by trusted trainers
• You must submit licence returns/results.
Filling in the Survey Form
The survey form has been kept as simple as possible – while allowing key information to be recorded
Most information requested is self-explanatory e.g.
• Pond details
• Your details
• Landowner details
Habitat suitability factors
Developed for the Habitat Suitability Index (HSI) for the great crested newt….
- the NARRS survey form contains space to record a simplified version of the HSI (see separate presentation).
For each survey technique, record numbers of amphibians seen (indicate presence only for larvae and newt eggs).
Visual search
Adu Imm Larva Egg
Common frog 1 0
Common toad
Great crested newt
Palmate newt ?
Smooth newt ?
Other species Crassula grass snake
Eggs of smaller newt species are not identifiable to species – so indicate with question mark if not sure which one you have
Survey conditionsThere are boxes to record the conditions under which the survey was conducted
Date
Time : to :
Air temperature oC
Water temperature oC
Water clarity (score 1-3)
Rain (score 0, 1, 2, 3)
Wind disturbing water (tick)
Bright moonlight (tick)
% Shoreline surveyed %
Number of traps used
(IF APPROPRIATE/LICENSED ONLY!)
Scoring for water clarity and rain given on survey form.
How many times to visit the pond?
Ideally, four survey visits – but in practice, as many as a surveyor can make, up to four
The survey form provides space to record information from up to four survey visits and the method/s used at each visit
When to survey the pond?
Ideally, an early survey in March and the rest mid-April to May (but later is still OK)
REMEMBER – your results are valuable and important to us however many methods you use or survey visits you are able to make!
Even NEGATIVE results (i.e. where you don’t find any species) are important!
www.narrs.org.uk
Photographs
• Photographs used in this presentation are by Fred Holmes, Phyl King, Will Watson, Steve Bolwell, Ben Driver and John Robinson
• Copyright of all photographs remains with the photographers and ARC
• These photographs should not be used for purposes other than NARRS training without the permission of the photographers.