1.7 Threat: Natural system modifications

Beneficial

Regulate water levels

1Three studies, including one replicated, site comparison study, in the UK and USA found that maintaining pond water levels, in two cases with other habitat management, increased or maintained amphibian populations or increased breeding success. One replicated, controlled study in Brazil found that keeping rice fields flooded after harvest did not change amphibian abundance or numbers of species, but changed species composition. One replicated, controlled study in the USA found that draining ponds increased abundance and numbers of amphibian species. Assessment: beneficial (effectiveness 70 %; certainty 65 %; harms 10 %).

2http://www.conservationevidence.com/​actions/​833

Unknown effectiveness (limited evidence)

Mechanically remove mid-storey or ground vegetation

3One randomized, replicated, controlled study in the USA found that mechanical understory reduction increased numbers of amphibian species, but not amphibian abundance. Assessment: unknown effectiveness — limited evidence (effectiveness 40 %; certainty 30 %; harms 0 %).

4http://www.conservationevidence.com/​actions/​781

Likely to be ineffective or harmful

Use herbicides to control mid-storey or ground vegetation

5Three studies, including two randomized, replicated, controlled studies, in the USA found that understory removal using herbicide had no effect or negative effects on amphibian abundance. One replicated, site comparison study in Canada found that following logging, abundance was similar or lower in stands with herbicide treatment and planting compared to those left to regenerate naturally. Assessment: likely to be ineffective or harmful (effectiveness 10 %; certainty 50 %; harms 50 %).

6http://www.conservationevidence.com/​actions/​778

Use prescribed fire or modifications to burning regime (forests)

7Eight of 15 studies, including three randomized, replicated, controlled studies, in Australia, North America and the USA found no effect of prescribed forest fires on amphibian abundance or numbers of species. Four found that fires had mixed effects on abundance. Four found that abundance, numbers of species or hatching success increased and one that abundance decreased. Assessment: likely to be ineffective or harmful (effectiveness 30 %; certainty 58 %; harms 40 %).

8http://www.conservationevidence.com/​actions/​877

Use prescribed fire or modifications to burning regime (grassland)

9Two of three studies, including one replicated, before-and-after study, in the USA and Argentina found that prescribed fires in grassland decreased amphibian abundance or numbers of species. One found that spring, but not autumn or winter burns in grassland, decreased abundance. Assessment: likely to be ineffective or harmful (effectiveness 10 %; certainty 40 %; harms 70 %).

10http://www.conservationevidence.com/​actions/​862