Providing evidence to improve practice

Action: Create ponds for great crested newts Amphibian Conservation

Key messages

  • Three before-and-after studies (including two replicated studies) in Germany and the UK found that naturally colonizing, captive-bred and translocated great crested newts established breeding populations at 57–75% of created ponds or sites. One systematic review in the UK found that there was no conclusive evidence that mitigation, which often included pond creation, resulted in self-sustaining populations.
  • Three replicated, before-and-after studies in the UK found that up to 88% of created ponds were colonized by translocated or by small numbers of naturally colonizing great crested newts. One replicated before-and-after study in the UK found that head-started great crested newts reproduced in 38% of created ponds.

 

Supporting evidence from individual studies

1 

A replicated before-and-after study in 1991–1993 of eight created ponds on restored opencast mining land in England, UK (Bray 1994) found that head-started great crested newts Triturus cristatus returned as adults to five ponds and reproduced in three in the second year. Adults returned to at least five of eight ponds and tadpoles were caught in three of five ponds netted in 1993 (2–5 tadpoles/pond). Sixteen ponds (30 x 20 m) with shelved edges and terrestrial habitat were created on restored opencast land. Ponds were planted with submerged and edge plants. Terrestrial habitat created included scrub, woodland, rough grassland, ditches and hedgerows. Newt eggs were collected and reared to larvae in aquaria. In 1991, 630 larvae were released into four ponds and in 1992, 1,366 larvae into eight ponds (66–243/pond). Ponds were surveyed using dip-netting in July 1993.

 

2 

A replicated, before-and-after study in 1994–2004 of 14 created ponds in wet meadows in the Luhe valley, Germany (Kinne 2004) found that captive-bred great crested newts Triturus cristatus established stable breeding populations in nine ponds. Fourteen ponds and many small pools of different designs were created. Some aquatic plants were introduced. Management also included fish removal, hanging wildfowl deterrents, mowing, scrub clearance and creation of hibernacula. From 1994, 60 captive-bred great crested newts were released into two created ponds annually. In 2000–2004, 5–10 adults were also released into the two ponds.

 

3 

A replicated, before-and-after study in 2005 of seven mitigation projects in England, UK (Lewis, Griffiths & Barrios 2007) found that translocated great crested newt Triturus cristatus established populations at four sites with created ponds. The four populations were classified as ‘medium’ sized (peak count: 16–86) after three or more years. Very low numbers were captured at the other three sites (peak count: 1–2). Newts used nine of 13 created ponds. Mitigation projects during development work had been carried out at least three years previously. Between one and three ponds were created and 2–164 newts translocated to each site in 1992–2000. Terrestrial habitat management was also undertaken at two sites. Monitoring was undertaken in March–May 2005 using egg searches, torch surveys, bottle trapping and mark-recapture.

 

4 

A replicated, before-and-after study in 1999–2006 of eight created ponds at a restored steelwork site in North Lanarkshire, Scotland, UK (McNeill 2010) found that small numbers of great crested newts Triturus cistatus colonized seven of the ponds within three years. Within one year, three of eight ponds were colonized by breeding newts. Up to six newts used each pond annually in 2000–2003. In 2006, the habitat suitability for newts for five of the created ponds was categorized as ‘average’ to ‘good’ (Habitat Suitability Index: 0.6–0.7). Two ponds were dry. There was no significant difference between the habitat suitability of created and existing ponds. Eight ponds were constructed in 1999. Newts were monitored by torchlight sampling, egg counts and metamorph counts at the perimeter fence. Created ponds were compared to seven existing ponds.

 

5 

A replicated, before-and-after study in 2008–2010 of 13 created ponds in a nature reserve with many existing ponds in England, UK (Furnborough et al. 2011) found that some created ponds were colonized by small numbers of great crested newts Triturus cristatus. One pond had six and another 18 newts in one year. However, the majority of ponds that contained newts had only one or two animals. In winter 2008–2009, 13 new ponds were created. Torchlight surveys were undertaken in March-June 2009–2010.

 

6 

A before-and-after study in 1998–2011 of eight created ponds in unimproved grassland in Kent, UK (Lewis 2012) found that great crested newts Triturus cristatus established a population in the ponds. The population increased by 30% within the first year following construction. The population was 10–14 newts in 2000–2006, increased to 32 in 2008 following draining and relining of ponds and then to 40 following construction of four additional ponds. Larvae were recorded in six ponds. There was no significant preference for older or newer ponds (117 vs 134 captures), apart from the first-time breeders that tended to colonize new ponds more than old ponds. Four experimental ponds (2 x 1 m; maximum depth 0.7 m) were created in a row in 1998 and four in 2009. Populations were sampled weekly in March–May using bottle trapping, torch surveys and mark-recapture.

 

7 

A systematic review in 2011 of the effectiveness of mitigation actions for great crested newts Triturus cristatus in the UK (Lewis 2012) found that neither the 11 studies captured or monitoring data from licensed mitigation projects showed conclusive evidence that mitigation, which often included pond creation, resulted in self-sustaining populations or connectivity to populations in the wider countryside. Only 22 of 460 licensed projects provided post-development monitoring data and of those, 16 reported that small populations, three medium and one large population was sustained. Two reported a loss of the population. A total of 127 (41%) of English and 46 (30%) of Welsh licence files contained licence return (reporting) documents. Of those, only 9% provided post-development monitoring data, a further 7% suggested surveys were undertaken, but no data were provided. The review identified 11 published or unpublished studies and 309 Natural England and 151 Welsh Assembly Government (licensing authorities) mitigation licence files. Mitigation measures were undertaken to reduce the impact of the development and included habitat management such as creating or restoring ponds, as well as actions to reduce deaths including translocations.

 

Referenced papers

Please cite as:

Smith, R.K., Meredith, H. & Sutherland, W.J. (2017) Amphibian Conservation. Pages 9-65 in: W.J. Sutherland, L.V. Dicks, N. Ockendon & R.K. Smith (eds) What Works in Conservation 2017. Open Book Publishers, Cambridge, UK.