Remove tree canopy to reduce pond shading

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One before-and-after study in Denmark found that translocated garlic toads established breeding populations following pond restoration that included canopy removal.
  • One before-and-after study in the USA found that canopy removal did not increase hatching success of spotted salamanders.


About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A before-and-after study in 1994–1997 of two restored ponds in Jutland, Denmark (Jensen 1997) found that translocated garlic toads Pelobates fuscus established breeding populations of in both ponds. Breeding was recorded in one in 1996 and the other in 1997. Ponds were restored by removing surrounding willows and by levelling the banks of one pond. Forty-three toads were captured from a pond being eliminated by development. Four egg strings were laid and raised in captivity. The 43 adults and 1,000 tadpoles were released into one of the restored ponds in 1994. Toads were monitored by tadpole and call surveys.

    Study and other actions tested
  2. A before-and-after study in 2005–2007 of a restored forest pond in Illinois, USA (Sacerdote & King 2009) found that hatching success of spotted salamanders Ambystoma maculatum did not increase following canopy removal. Two egg masses failed in 2005 and 2006 before canopy removal and two failed in 2007 after removal. Restoration started in 2000 and included destruction of drainage tiles, clearing of invasive plants and prescribed burning. Canopy thinning was undertaken in winter 2006–2007. An egg mass was placed in two mesh enclosures (56 x 36 x 36 cm) in the pond. Eggs were monitored every five days until hatching was complete.

    Study and other actions tested
Please cite as:

Smith, R.K., Meredith, H. & Sutherland, W.J. (2020) Amphibian Conservation. Pages 9-64 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Amphibian Conservation

This Action forms part of the Action Synopsis:

Amphibian Conservation
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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