Conservation policy and practice reviews

HCI is involved in topical and cutting edge issues through commissions and independent research. Below are examples of a recent and a longer-term study.

Olympic Games 2012 impact review: great crested newt.

In 2007  Tom Langton undertook a review of a mitigation project at Hog Hill, London Borough of Redbridge for the Mayor’s Office of the Greater London Authority. A replacement cycle track to one lost in the Olympic Park construction zone has been built on farmland, between a pond  and adjoining woodland. This was habitat occupied by the great crested newt,  which is highly fragmented and scarce in the capital city. The Method Statement and its implementation, licensed by Natural England,  was  evaluated by HCI.

Hog Hill

Olympic Games 2012, London









Green Frog Information Programme.

HCI has produced two reports on the Pool frog in advance of, and following English Nature’s release of this species at a location near Thetford in Norfolk.

Controversy has surrounded evidence relating to the nativeness of pool frogs to England. This is set around a key claim that sub-fossil pelvic frog bones can be identified precisely to species, contrary to the views of  leading  European amphibian frog bone experts. Swedish pool frogs were released into the UK at a well known wildlife area in Norfolk  and immediately given legal protection with the minimum of consultation. Swedish pool frogs have been considered by Natural England (formerly English Nature) to have been a relictual native that somehow survived the ‘little ice age’ (1650-1850) . Other views consider that a mix of  ‘green frogs’; marsh frogs, pool frogs and even their hybrid the edible frog died out much earlier and since the last full ice age and have been introduced to Britain on multiple occasions over the last 2000 years.  Green frogs were  imported with other human food species to boost food supply by humans colonising England from Scandinavia and Northern Europe. Fossil evidence is crucial to the science of these issues, but funding of the research  needed to end  uncertainty has been shelved and substituted with releases.

Below are common/grass frog pelvic bones (the ilia with the socket that receives the ball of the thigh bone or femur). These bones, (all of common frog) illustrate variation in bone shapes. Leading experts believe that only frog head bones can be used for definitive identification. DNA extraction from sub-fossil bones is likely to answer this question in time. Meanwhile some conservationists question the wisdom of spending public finance on pool frog introduction and giving them legal protection. This is not least because all of the three types of  green frog have already become established elsewhere in southern and eastern England and will eventually mix with any pure pool frog introductions, especially if our climate further warms.

Pool frog This small sample of common or grass frog pelvic bones show how bone shape variation is extensive. The top bone is complete.








The case is interesting as it illustrates divergence in conservation opinion. Some believe public funds should be spent on protecting only species definitely proven to be native to a country without human transfer. Others believe the UK (and other largely highly disturbed landscapes) should encourage possible past-natives and even non-natives, especially declining ones, moving them from outside their natural range into climatic zones that they might enter if they could cross natural (as opposed to man-made) barriers to dispersal. There is a need for a strategic international approach and guidelines to address these complex issues. Current policies are simplistic, outdated and may result in confusion, despite the resulting significant draw on public funds when government agencies take decisions.  

A broken and partly degraded  sub-fossil bone found at Gosberton in Lincolnshire has been attributed to that of a Pool frog. A better preserved bone is reported from Ely. Several bone experts doubt the Gosberton and Ely  identifications. Green and brown frog bones overlap in shape and size and the degree of overlap has not yet been fully documented. Anyone interested in viewing detailed images of these bones should contact the HCI office.  

As a protected European species, the UK government can now justify  financial resources to research this problem of definitive bone identification further, through careful sampling of natural sediments and other deposits, and using dna and morphometric studies. Although this matter lies outside the  risk analysis for the  introduction (now undertaken), it must surely now be important in assessment of  the ethical and financial probity of this work and its future resourcing.

GRIP Report no.1  On the approach to investigating the historic status of the Green/Water frog Rana lessonae in England using archive material, with particular reference to English Nature funded Research Reports and proposals to release Pool frogs in the wild in England.  2005  J.A. Burton and T.E.S. Langton.


Click here for text  grip-report-1


GRIP Report no.2 Pool frog Rana lessonae in Britain: past nativeness unresolved. On the verification of sub-fossil bone identification. 2005  T.E.S. Langton and J.A. Burton.


Click here for text  grip-report-2








Great crested newt appraisal

Due to publication of the existence of this otherwise private report to the European Commission from 2009, it is being made public. Click GCN Report GCN PONDS FINAL