In an attempt to identify the most important sites in Kent for amphibians and reptiles, KRAG has created a Key Site Register.
Details of some of these sites will be added to this page at a later date but already detailed is the rationale for key sites and their criteria.
02. What is a Key Site and how are they identified?
Key Sites in Kent
The extensive survey work that KRAG undertakes means that we have many thousands of herpetofauna records for the county. However, the next step is to be able to decide, objectively, which sites are the most important in Kent. Recent advances with KRAG’s recording database mean that the process of identifying potential key sites can be automated. Flagged sites are then reviewed and those that are considered to exceed the minimum criteria for designation are proposed to the KRAG Committee. Once a site is formally designated, details are sent to the Kent Wildlife Trust so that the information can be used to help designate Local Wildlife Sites (LWS). Since LWS are protected through policies in the Kent and Medway Structure Plan, we now have a mechanism to identify and safeguard important herpetofauna sites from inappropriate development activities.
Google Earth image representing Kent Key Sites – Reptiles
Imagery © 2017 Data SIO, NOAA, U.S. Navy, NGA, GEBCO, Landsat / Copernicus, Map data © Google
A challenge in defining key sites, is identifying (and adequately recording) site boundaries. We have now adopted Google Maps as our preferred tool for this. The great thing about Google Maps is that the maps are all digital and can be quickly and easily updated as more information is collected. The maps can be modified by any of the KRAG Committee and the recorder can add additional detail on different species as appropriate. As a taster for what is now possible, here is a live link to Polhill Bank (Site Ref 529), one of the 34 Key Reptile Sites that KRAG has designated to date.
View Polhill Bank (Site Ref: 529) in a larger map
Polhill Bank was designated a Key Reptile Site on 7th October 2008 because the site supports all four of Kent’s widespread reptile species. Detailed information on population status for some species is lacking, but all four species have been recorded in recent years.
03. Criteria for Reptiles
In November 1999 Froglife published the excellent Reptile Survey Advice Sheet that deals with how to conduct reptile surveys and interpret their results. There hasn’t been anything published since that has offered a better review. One of the outstanding achievements of the Froglife Reptile Survey advice sheet was in devising a simple, but meaningful tool by which reptile sites could be formally assessed. Such survey assessments led to the promotion of Key Reptile Sites.
“The Key Reptile Site Register is a mechanism designed to promote the safeguard of important reptile sites.”
KRAG have adopted and slightly amended this methodology to create criteria used to identify key reptile sites.
(1) All sites with sand lizard.
(2) The site supports three or more reptile species.
(3) The site supports two snake species.
(4) The site supports an exceptional population of one species.
(5) The site supports an assemblage of species scoring at least four, based on the relative population scoring system described by Froglife (1999).
(6) The site is of particular regional importance due to local rarity. In Kent, such sites will include (but not be exclusive to) any areas that support a ‘good’ or ‘exceptional’ population of adder, based on the population scoring system described by Froglife (1999).
(7) The boundary of a Key Reptile Site may be defined as an area of land within a specified ownership.
(8) The boundary of a Key Reptile Site may be defined as land within a specified Survey Region that may be owned and/or managed by one or more landowners.
(9) Greater emphasis will be placed on promoting designated sites where available data indicates the presence of a breeding population. Breeding will be determined by the identification of eggs, neonates and/or juveniles.
(10) Greater emphasis will be placed on promoting designated sites that include terrestrial habitat features that are deemed of particular importance to reptiles. Such features may include hibernation areas, nesting sites and foraging areas.
Froglife’s Scoring System
Froglife’s scoring system for a site is based upon the number of adult animals of each species found in one day by one person. If artificial cover objects (refugia) are used then their density should be no more than 10 per hectare.
For adder and grass snake.
Under 5 animals score 1 (Low population)
5 – 10 animals score 2 (Good population)
Over 10 animals score 3 (Exceptional population)
For slow worm and viviparous lizard.
Under 5 animals score 1 (Low population)
5 – 20 animals score 2 (Good population)
Over 20 animals score 3 (Exceptional population)
Example. If 2 Adders (1 point), 7 Grass Snakes (2 points) and 33 Slow-worm (3 points) were seen on one site then the site score would total 6 points and would qualify as a key site.
04. Criteria for Amphibians
Defining Key Amphibian Sites usually concerns breeding ponds. However, the criteria must take into consideration important terrestrial habitat. KRAG has therefore developed the following system that borrows heavily from the SSSI scores described by Trevor Beebee and Robin Grayson in the Herpetofauna Workers Manual (now out of print but can be downloaded from the link)
(1) All sites with Natterjack Toads.
(2) All sites with an exceptional (or large) population or metapopulation of Great Crested Newts.
(3) All sites with a good or exceptional population of Common Toads.
(4) Sites with amphibian assemblages that score 5 or more on the SSSI scoring system described by Beebee and Grayson (1998). Greater emphasis to be placed on sites with the highest scores.
(5) The boundary of a Key Amphibian Site may be defined as an area of land within a specified ownership that may include a single waterbody or a collection of waterbodies that supports a metapopulation of one or more species.
(6) The boundary of a Key Amphibian Site may be defined as an area of land within a specified ownership that does not include a waterbody, but does include terrestrial habitat that is considered important for one or more species (particularly for common toad).
(7) The boundary of a Key Amphibian Site may be defined as land within a specified Survey Region that may be owned and/or managed by one or more landowners. The site may include a single waterbody, a collection of waterbodies that support a metapopulation of one or more species and/or terrestrial habitat that is considered important for one or more species.
(8) The boundary of the Key Amphibian Site should include all areas of suitable terrestrial habitat that are located within 250 m of each waterbody that is occupied by the species (or species assemblage) of interest. Such terrestrial habitat is considered critical to the functioning of a metapopulation.
(9) Where a waterbody that is occupied by the species (or species assemblage) of interest is located outside of a Key Amphibian Site boundary, but situated within 500 m of another occupied waterbody that is already located within a Key Amphibian Site boundary, both waterbodies and their associated terrestrial habitat should be considered for inclusion within the Key Amphibian Site boundary.
(10) Key Amphibian Sites should relate to waterbodies and terrestrial habitat that is located on the proximal side of significant dispersal barriers.
Beebee and Grayson’s SSSI Scoring System
The SSSI scoring system for a site is based upon counts for a single visit.
For Common Frogs count the number of clumps of spawn.
Under 50 clumps score 1 (Low population)
50 – 500 clumps score 2 (Good population)
Over 500 clumps score 3 (Exceptional population)
For Great Crested Newts count the number of adults seen or netted by day or counted by torchlight.
Under 5 adults seen or netted by day or under 10 adults counted by torchlight score 1 (Low population)
5-50 adults seen or netted by day or 10-100 adults counted by torchlight score 2 (Good population)
Over 50 adults seen or netted by day or over 100 adults counted by torchlight score 3 (Exceptional population)
For Smooth and Palmate Newts.
Under 10 adults in a visit score 1 (Low population)
10 – 100 adults score 2 (Good population)
Over 100 adults score 3 (Exceptional population)
For Common Toads.
Under 100 adults counted or under 500 adults estimated in a visit score 1 (Low population)
100 – 1000 adults counted or 500 – 5000 adults estimated in a visit score 2 (Good population)
Over 1000 adults counted or over 5000 adults estimated in a visit score 3 (Exceptional population)
Example. If 3 Palmate Newts (1 point), 17 Smooth Newts (2 points) and 133 Frog spawn clumps (2 points) were seen on one site then the site score would total 5 points and would qualify as a key site.