Beneficial

Create skylark plots

1All four studies (two replicated, controlled trials) from Switzerland and the UK investigating the effect of skylark plots on Eurasian skylarks found positive effects, including increases in population size. A replicated study from Denmark found skylarks used undrilled patches in cereal fields. Three studies (one replicated, controlled) from the UK found benefits to plants and invertebrates. Two replicated studies (one controlled) from the UK found no significant differences in numbers of invertebrates or seed-eating songbirds. Assessment: beneficial (effectiveness 100 %; certainty 80 %).

2http://www.conservationevidence.com/actions/540

Leave cultivated, uncropped margins or plots (includes ‘lapwing plots’)

3Seventeen of nineteen individual studies looking at uncropped, cultivated margins or plots (including one replicated, randomized, controlled trial) primarily from the UK found benefits to some or all target farmland bird species, plants, invertebrates or mammals. Two studies (one replicated) from the UK found no effect on ground beetles or most farmland birds. Two replicated site comparisons from the UK found cultivated, uncropped margins were associated with lower numbers of some bird species or age groups in some areas. Assessment: beneficial (effectiveness 100 %; certainty 65 %).

4http://www.conservationevidence.com/actions/562

Likely to be beneficial

Create beetle banks

5Five reports from two replicated studies (one controlled) and a review from Denmark and the UK found beetle banks had positive effects on invertebrate numbers, diversity or distributions. Five replicated studies (two controlled) found lower or no difference in invertebrate numbers. Three studies (including a replicated, controlled trial) from the UK found beetle banks, alongside other management, had positive effects on bird numbers or usage. Three studies (one replicated site comparison) from the UK found mixed or no effects on birds, two found negative on no clear effects on plants. Two studies (one controlled) from the UK found harvest mice nested on beetle banks. Assessment: likely to be beneficial (effectiveness 80 %; certainty 60 %).

6http://www.conservationevidence.com/actions/651

Leave overwinter stubbles

7Eighteen studies investigated the effects of overwinter stubbles. Thirteen studies (including two replicated site comparisons and a systematic review) from Finland, Switzerland and the UK found leaving overwinter stubbles benefits some plants, invertebrates, mammals or birds. Three UK studies (one randomized, replicated, controlled) found only certain birds were positively associated with overwinter stubbles. Assessment: likely to be beneficial (effectiveness 90 %; certainty 50 %).

8http://www.conservationevidence.com/actions/695

Reduce tillage

9Thirty-four studies (including seven randomized, replicated, controlled trials) from nine countries found reducing tillage had some positive effects on invertebrates, weeds or birds. Twenty-seven studies (including three randomized, replicated, controlled trials) from nine countries found reducing tillage had negative or no clear effects on some invertebrates, plants, mammals or birds. Three of the studies did not distinguish between the effects of reducing tillage and reducing chemical inputs. Assessment: likely to be beneficial (effectiveness 60 %; certainty 60 %).

10http://www.conservationevidence.com/actions/126

Undersow spring cereals, with clover for example

11Eleven studies (including three randomized, replicated, controlled trials) from Denmark, Finland, Switzerland and the UK found undersowing spring cereals benefited some birds, plants or invertebrates, including increases in numbers or species richness. Five studies (including one replicated, randomized, controlled trial) from Austria, Finland and the UK found no benefits to invertebrates, plants or some birds. Assessment: likely to be beneficial (effectiveness 60 %; certainty 43 %).

12http://www.conservationevidence.com/actions/136

Unknown effectiveness (limited evidence)

Convert or revert arable land to permanent grassland

13All seven individual studies (including two replicated, controlled trials) from the Czech Republic, Denmark and the UK looking at the effects of reverting arable land to grassland found no clear benefits to birds, mammals or plants. Assessment: unknown effectiveness — limited evidence (effectiveness 0 %; certainty 20 %).

14http://www.conservationevidence.com/actions/561

Create rotational grass or clover leys

15A controlled study from Finland found more spiders and fewer pest insects in clover leys than the crop. A replicated study from the UK found grass leys had fewer plant species than other conservation habitats. A UK study found newer leys had lower earthworm abundance and species richness than older leys. Assessment: unknown effectiveness — limited evidence (effectiveness 0 %; certainty 10 %).

16http://www.conservationevidence.com/actions/643

Increase crop diversity

17Four studies (including one replicated, controlled trial) from Belgium, Germany and Hungary found more ground beetle or plant species or individuals in fields with crop rotations or on farms with more crops in rotation than monoculture fields. Assessment: unknown effectiveness — limited evidence (effectiveness 0 %; certainty 9 %).

18http://www.conservationevidence.com/actions/560

Plant cereals in wide-spaced rows

19Two studies (one randomized, replicated, controlled) from the UK found planting cereals in wide-spaced rows had inconsistent, negative or no effects on plant and invertebrate abundance or species richness. Assessment: unknown effectiveness — limited evidence (effectiveness 0 %; certainty 18 %).

20http://www.conservationevidence.com/actions/564

Plant crops in spring rather than autumn

21Seven studies (including two replicated, controlled trials) from Denmark, Sweden and the UK found sowing crops in spring had positive effects on farmland bird numbers or nesting rates, invertebrate numbers or weed diversity or density. Three of the studies found the effects were seasonal. A review of European studies found fewer invertebrates in spring wheat than winter wheat. Assessment: unknown effectiveness — limited evidence (effectiveness 40 %; certainty 35 %).

22http://www.conservationevidence.com/actions/137

Plant nettle strips

23A small study from Belgium found nettle strips in field margins had more predatory invertebrate species than the crop, but fewer individuals than the crop or natural nettle stands. Assessment: unknown effectiveness — limited evidence (effectiveness 50 %; certainty 10 %).

24http://www.conservationevidence.com/actions/118

Sow rare or declining arable weeds

25Two randomized, replicated, controlled studies from the UK identified factors important in establishing rare or declining arable weeds, including type of cover crop, cultivation and herbicide treatment. Assessment: unknown effectiveness — limited evidence (effectiveness 40 %; certainty 15 %).

26http://www.conservationevidence.com/actions/642

No evidence found (no assessment)

27We have captured no evidence for the following interventions:

• Add 1 % barley into wheat crop for corn buntings
• Create corn bunting plots
• Leave unharvested cereal headlands in arable fields
• Use new crop types to benefit wildlife (such as perennial cereal crops)

Evidence not assessed

Implement ‘mosaic management’, a Dutch agri-environment option

28A replicated, controlled before-and-after study from the Netherlands found mosaic management had mixed effects on population trends of wading bird species. A replicated, paired sites study from the Netherlands found one bird species had higher productivity under mosaic management. Assessment: this intervention has not been assessed.

29http://www.conservationevidence.com/actions/130

Plant more than one crop per field (intercropping)

30All five studies (including three randomized, replicated, controlled trials) from the Netherlands, Poland, Switzerland and the UK looking at the effects of planting more than one crop per field found increases in the number of earthworms or ground beetles. Assessment: this intervention has not been assessed.

31http://www.conservationevidence.com/actions/124

Take field corners out of management

32A replicated site comparison from the UK found a positive correlation between grey partridge overwinter survival and taking field corners out of management. Brood size, ratio of young to old birds and density changes were unaffected. Assessment: this intervention has not been assessed.

33http://www.conservationevidence.com/actions/128