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Providing evidence to improve practice

Individual study: Restoration of ponds in a landscape and changes in common frog (Rana temporaria) populations, 1983-2005

Published source details

Williams L.R. (2005) Restoration of ponds in a landscape and changes in common frog (Rana temporaria) populations, 1983-2005. Herpetological Bulletin, 94, 22-29


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Create ponds for frogs Amphibian Conservation

A continuation of a previous study (Williams & Green 1993), in this case combining data from 31 ponds in a grass and woodland park in 1983–2004 (Williams 2005), found that pond creation and restoration significantly increased reproduction by common frog Rana temporaria. Numbers of egg masses increased from 40 in 1983 to 1,852 in 2002, but then declined to 1,000 in 2004. Numbers of egg clumps increased with pond size and eight ponds contained 89% of the egg masses. The numbers of ponds used for breeding each year increased from one in 1983 to 20 in 2000. Breeding tended to occur two years after pond creation or restoration. Eggs, tadpoles and frogs were introduced and removed from ponds by the public, particularly in 1984. Colonization may not therefore have been natural.

 

Deepen, de-silt or re-profile ponds Amphibian Conservation

In a continuation of a study (Williams & Green 1993), a before-and-after study in 1983–2004 of 31 ponds in Middlesex, UK (Williams 2005) found that pond restoration and creation resulted in a significant increase in total common frog Rana temporaria egg masses. Numbers increased from 40 egg masses in 1983 to 1,852 in 2002, although then declined to 1,000 in 2004. Numbers of egg clumps increased with pond size and eight ponds contained 89% of the spawn. The numbers of ponds used for breeding each year increased from one in 1983 to 20 in 2000. Breeding tended to occur two years after pond creation or restoration. Egg clumps were counted in restored ponds in February–March as an index of numbers of breeding females. An unmonitored number of eggs, tadpoles and frogs were introduced and removed from ponds by the public, particularly in 1984. Colonization may not therefore have been natural.

 

(Summarised by Rebecca K Smith)