Individual study: Pond restoration and common frog populations at Fryent Country Park, Middlesex, 1983-1993
Williams L.R. & Green M. (1993) Pond restoration and common frog populations at Fryent Country Park, Middlesex, 1983-1993. London Naturalist, 72, 15-24
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
A replicated before-and-after study in 1983–1993 of eight created ponds in a Country Park on restored farmland in England, UK (Williams & Green 1993) found that common frogs Rana temporaria colonized and reproduced in six of the ponds (see also Williams 2005). By 1992, a total of 195 egg clumps were counted (1–70/pond). Numbers declined to 123 egg clumps in 1993 (0–32/pond), which was considered to be due to drought. Ponds of 4–625 m2 were created in 1983–1987. Twenty ponds were also restored in the area increasing the total pond area from 2,248 m2 in 1983 to 4,965 m2 in 1993. Egg clumps were counted, as an index of numbers of breeding females, in created ponds in February–March.
Deepen, de-silt or re-profile ponds
A before-and-after study in 1981–1993 of 20 restored ponds in Middlesex, UK (Williams & Green 1993) found that the population of common frogs Rana temporaria increased as the number of ponds restored by deepening increased (see also Williams 2005). Egg clumps increased from 40 in one pond in 1983 to 584 in 1992 (1–370/pond). However, numbers declined to 399 egg clumps in 1993, which was considered by the authors to be due to drought. Many ponds within a country park had dried up and so were restored by deepening and enlarging (4–1,680 m2) in 1981–1993. Eight ponds were also created in the area increasing the total pond area from 2,248 m2 in 1983 to 4,965 m2 in 1993. Egg clumps were counted in restored ponds in February–March as an index of numbers of breeding females.
(Summarised by Rebecca K Smith)