Monitoring created seasonal pools for functional success: a six-year case study of amphibian responses, Sears Island, Maine, USA

  • Published source details Vasconcelos D. & Calhoun A.J.K. (2006) Monitoring created seasonal pools for functional success: a six-year case study of amphibian responses, Sears Island, Maine, USA. Wetlands, 26, 992-1003.


This study is summarised as evidence for the following.

Action Category

Excavate freshwater pools

Action Link
Marsh and Swamp Conservation

Restore wetland

Action Link
Amphibian Conservation
  1. Excavate freshwater pools

    A replicated study in 1997–2002 of excavated ephemeral pools/potholes (within replanted uplands) in Maine, USA (Vasconcelos & Calhoun 2006) reported that they were colonized by vegetation – mostly common cattail Typha latifolia – within five years. These results were not tested for statistical significance. After five years, cattail dominated three of three pools (60–84% of their vegetation cover) and 21 of 50 surveyed potholes (percent cover not reported). Shrubs were present in 30 of 50 surveyed potholes and were the dominant vegetation in seven (percent cover not reported). The study also reported that vegetation cover and species richness increased between three and five years after excavation (data not reported and not statistically tested). Methods: In autumn 1997, three seasonal freshwater pools (350–900 m2) and 200 seasonal freshwater potholes (0.3–110 m2) were excavated in an abandoned commercial development. Fill material was removed to expose soil from the forested wetland that historically occupied the site. Upland grasses, shrubs and trees were planted around the pools/potholes to stabilize the soil. Emergent vegetation cover, up to the high water mark, was estimated in each pool and 50 potholes in May–September 1999–2002.

    (Summarised by: Nigel Taylor)

  2. Restore wetland

    A small, replicated study in 1999–2004 of three seasonal ponds and 200 potholes created at a forested wetland restoration site on Sears Island, Maine, USA (Vasconcelos & Calhoun 2006) found that wood frogs Rana sylvatica and spotted salamanders Ambystoma maculatum colonized and reproduced in the three ponds and bred in 28% of potholes. Spring peeper Pseudacris crucifer colonized and bred in one pond and American toad Bufo americanus visited but did not breed in two ponds. Reproductive success varied between ponds for wood frogs (0.2–48.4 juveniles/egg mass) and spotted salamanders (1.8–5.4). Metamorphosis of these species was only completed in one pothole before drying. In 1997, two ponds were excavated within the original wetland (350 and 600 m2) and one dry detention basin was converted to a pond (900 m2). Approximately 200 small potholes (0.3–110 m2) were also created. Amphibians were monitored in the three ponds in March–October using enclosure drift-fencing. Pitfall traps were installed in pairs every 10 m either side of fences (9–18 pairs/pond). Eggs were counted within ponds and 50 potholes.


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