Individual study: Does it help to restore ponds? A case of the tree frog (Hyla arborea)
Hels T. & Fog K. (1995) Does it help to restore ponds? A case of the tree frog (Hyla arborea). Memoranda Societatis pro Fauna et Flora Fennica, 71, 93-95
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 1991–1994 of nine created ponds on the island of Lolland, Denmark (Hels & Fog 1995) found that European tree frogs Hyla arborea colonized three of the ponds by 1994. Those colonized were within 500 m of densely populated ponds. The ponds were dug in 1991–1993. Frogs were monitored by call surveys and dip-netting each year.
Deepen, de-silt or re-profile ponds
A replicated, controlled study in 1991–1994 of 29 restored ponds on the island of Lolland, Denmark (Hels & Fog 1995) found that numbers of calling male tree frogs Hyla arborea increased significantly and larvae increased and then decreased after dredging. Numbers of calling males increased significantly in dredged but not undredged ponds from 1991 to 1994. The year after dredging, numbers of larvae were significantly higher in dredged ponds compared to undredged ponds; numbers had been similar before dredging. However, two years after dredging, there was no significant difference between numbers of larvae in dredged and undredged ponds. In 1991–1993, 29 ponds that had at least three calling males were restored by dredging. Water was usually pumped out and mud removed from the bottom. Frogs were monitored by call surveys and dip-netting (30 minutes) in 1991–1994.
(Summarised by Rebecca K Smith)