4.9 Threat: Natural system modification
p. 278-280
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Based on the collated evidence, what is the current assessment of the effectiveness of interventions for natural system modification?
Likely to be beneficial | ● Raise water levels in ditches or grassland |
Unknown effectiveness (limited evidence) | ● Create scrapes and pools |
No evidence found (no assessment) | ● Re-wet moorland |
Likely to be beneficial
Raise water levels in ditches or grassland
1Eight studies (including two replicated, controlled trials) from Denmark, the Netherlands and the UK found raising water levels increased numbers of birds, invertebrates or plants or allowed wet grassland plant species to establish more rapidly. Three studies (two replicated) from the Netherlands and the UK found raising water levels had negative, limited or no effects on plants or birds. A replicated study from the UK found unflooded pastures had a greater weight of soil invertebrates than flooded pastures. Assessment: likely to be beneficial (effectiveness 100%; certainty 55%).
http://www.conservationevidence.com/actions/121
Unknown effectiveness (limited evidence)
Create scrapes and pools
2Five studies (including a replicated, controlled, paired trial) from Sweden and the UK found creating scrapes and pools provided habitat for birds, invertebrates or plants or increased invertebrate diversity. Two replicated studies (one controlled, paired) from Ireland and the UK found mixed or no differences in invertebrate numbers between created ponds and controls="true" or natural ponds. A study in Sweden found fewer fish species in constructed than natural wetlands. Assessment: unknown effectiveness — limited evidence (effectiveness 100%; certainty 28%).
http://www.conservationevidence.com/actions/153
Manage heather by swiping to simulate burning
3A replicated, controlled trial from the UK found heather moorland subject to flailing had fewer plant species than burned plots but more species than unflailed plots. Assessment: unknown effectiveness — limited evidence (effectiveness 40%; certainty 9%).
http://www.conservationevidence.com/actions/151
Manage heather, gorse or grass by burning
4A long-term replicated, controlled trial in Switzerland found burning of chalk grassland did not increase the number of plant species. A replicated, controlled trial in the UK found more plant species on burned than unburned heather moorland. Assessment: unknown effectiveness — limited evidence (effectiveness 10%; certainty 5%).
http://www.conservationevidence.com/actions/152
Remove flood defence banks to allow inundation
5A controlled before-and-after study from the UK found a stretch of river that was allowed to flood had more bird species and territories than a channelized section. A study from Belgium found flooding and mowing increased plant species richness in meadow plots. Assessment: unknown effectiveness — limited evidence (effectiveness 80%; certainty 10%).
http://www.conservationevidence.com/actions/122
No evidence found (no assessment)
6We have captured no evidence for the following intervention:
Re-wet moorland
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