Research Evidence

  • Over-eating - me? Stock graze the grass they like and leave what they don't like alone - one of the biggest invaders is bracken which has increased as grazing has intensified

Research Evidence – all reinforced by the positive results on Bredon Hill

Here is a summary of the research evidence gathered by Ian Wells since becoming aware that we were down to the last singing lark on the high hills in 2015. The evidence suggests that they will not come back under the current short-grazing regime. Whilst grazing in the mid and lower slopes is beneficial it is not beneficial on the tops and reducing grazing to leave the grass longer is going to add to species diversity generally, not just benefit skylarks. Furthermore it will not lead to scrub incursion. Here is his evidence:

The  sward is now too sort for skylarks in their most recent territories. Evidence: It is not controversial that larks prefer  20-40cm sward. Research included talks with Chris Kriek conservation supervisor at the RSPB, review of Paul Donald’s authoritative  “The Skylark” , an excellent summary of research. Photos from a 25km survey of Clee Hill showed clearly and simply that larks were present on open, dry slopes with 20cm plus sward (like the High Malverns were a few years ago when larks bred) and not on adjacent tightly grazed but otherwise similar areas. Leo Smith Shropshire County Bird Recorder and author of Birds of Shropshire reviewed the results and wondered why a survey was needed as it was obvious to him that tight grazing meant no skylarks. The positive results of more lenient grazing on Bredon Hill seal the argument – nothing much else changed there. There are skylarks breeding in Ashton Court in the middle of Bristol and they were encouraged to make a temporary return to Wimbledon Common in 2015 – the common factor was longer grass.

Tight grazing is probably not good for other species either. Evidence: A consequence of grazing is often an increase of coarse invasive grasses and it looks like this is what is happening – a proper plot survey would be needed to confirm it, but it is certainly far from clear that the cows and sheep are doing anything more than mowing the lawn. In the previous longer grass there used to be grasshoppers and all manner of moths, beetles and bugs. You don’t see many now. Grayling Butterflies need bare patches not tight sward. If the munching continues the grass will be too short for meadow pipits too. That means no ground nesting birds on the high hills. I understand some species diversity research was done in recent years and those results would be interesting to see and need repeating.

Grazing is not needed to keep the high hills scrub free – in fact it encourages shrub growth. Evidence: In the 10 years of no grazing from 1992 the high slopes did not suffer shrub incursion – the sward length settled at 30cms or so. The photos in the slider above were taken in 1995 and again in 2000 and it looked like that until grazing started again around 2002. The blanket statement “grazing is important to control shrub incursion” may be true on the mid and lower slopes (commons) but not true on the high hills, especially if the mid slopes are controlled to prevent any upward incursion. The slider photo comparing 2013 and five years later shows considerable bracken invasion as grazing intensified. Grazing that is too tight on skylark territories on the commons or the high hills will not sustain skylarks.

Tight grazing is making the hills less beautiful: Evidence: Subjective one this, but the government has produced guidance on natural beauty quoted in the Malvern Hills Management Plan: ‘“Natural Beauty” is not just the look of the landscape, but includes landform and geology, plants and animals, landscape features and the rich history of human settlement over the centuries’. Looking at the photos above, you can decide which you would prefer to go for a walk in 1995, 2000 or 2017.

It seems there skylarks looking for territory early in the season – there were two records of larks on North Hill and Sugarloaf (They did not take up territory of course). So whatever the pattern of national decline they are around. Disturbance may well be a factor but North Hill is still quieter than the Worcester Beacon was when the Worcester Beacon had singing larks. There is every hope that larks will return if he habitat is right. Once again demonstrated at Bredon, No chance if it isn’t.