Cinnabar moth July 21
I have always pulled ragwort up off my allotment but reading Wilding by Isabella Tree made me think about what I do. What stopped me in my tracts was the fact that 177 species of insect use common ragwort as a source of nectar or pollen. That’s quite a lot on a small plot!
Seven species of beetle, twelve species of flies, one macromoth – the cinnabar, with its distinctive black-red-and-yellow rugby jersey caterpillars – and seven micromoths feed exclusively on common ragwort. It is a major source of nectar for at least thirty species of solitary bees, eighteen species of solitary wasps and fifty insect parasites. (Tree, 2018, p142)
I know ragwort can be toxic to horses especially and cattle but apparently they only eat it if they are in an over-grazed field where there is not enough grass for them. There are other plants that can have the same toxic effect on them: foxgloves, elder, spindle and daffodil all of which I have on the plot (although I have no horses or cattle!) and no one bats an eyelid about them.
The seed can stay dormant in the soil for about 10 years and only needs a slight scratching around it to stimulate germination which would explain how I come to have it each year on my plot and the wildlife plot. This year, however, I am going to let it grow on the wildlife plot.
And if you want more information about micromoths, this site is useful.
A volunteer who works with me on the wildlife plot suggested I read Wilding: The return of nature to a British farm by Isabella Tree. I hadn’t heard of this book but it was highly commended by the 2019 Wainwright Book Prize and so there is no time like the present to get started on it.
It is a fantastic story about wilding the Knepp Estate, a mixed farm, which through grants and lack of money became the most amazing return to nature with a little help from the owners. The one thing the book does really well is show the inter-connectedness of everything. So, rather than write the normal sort of review, I am going to record some of the elements which were new to me or amazed me.
- I didn’t know about the relationship between oak trees and jays. Jays eat acorns but also store them. They peck and push them far down into the soil – in fact to the very distance that is most propitious for an acorn to sprout. During the summer months they leave the acorns as there is plenty of other food but then eventually return. By now the acorn has sprouted so the jay pulls it up just enough to get to the cotyledon leaves which remain underground. Because the oak sends down strong roots very early in its life, it is often strong enough to withstand this attack and will carry on growing. If that isn’t enough, the jay will bury the acorns at the edge of scrub plants and these continue to grow and eventually provide a thorny tree guard for the oak, preventing cows, deer and other grazing animals getting to it. So, not only does the jay get a carbohydrate rich food, but it plants the seeds from which the next oaks will grow. In a four week period a jay can bury about 7,500 acorns. Why aren’t we allowing jays to do this for us instead of recruiting hundreds of volunteers to plant trees that need plastic guards?
- By not using herbcides, pesticides and any other cide on the farm the number and type of dung beetles increased dramatically. In fact the owners timed how long it took for beetles to arrive at a newly deposited pile of dung and it was three minutes. Using wormers and paratiscides on cattle kills the dung beetles or any other insect that eats the dung. Because dung beetles tunnel, this has an impact on the quality of the soil reducing the aeration, fertility and ability to soak up water. But even better, the dung beetles reduce the parasites in the dung by eating it up quickly and therefore reduce the amount of wormers needed. And of course, if you use wormers, it reduces the beetles and other insects which then has an effect on the birds and so on up through the food chain.
- Honeysuckle provides nesting material for doormice. I didn’t know that and we don’t really have any, honeysuckle or doormice, on the wildlife plot so need to take some cuttings and grow some if only for the scent.
Credit – Getty images
What comes through loud and clear in the book is something Tree refers to as ‘species-shifting syndrome’ as exemplified by nightingales and purple emperor butterflies. Nightingales are often referred to as a woodland species but left to their own devices at Knepp, the nightingales have nested in wide, prickly hedges and open-grown scrub both of which are rich in insects, not woodland. Could it be that they are seen in coppiced woodland because they are clinging on to a habitat that is present, not their preferred but the least worst thing. Time and again, Tree says that if you look in wildlife guides over a 100 years ago the range and type of habitat described in them is different to the modern guides. If we take the modern guides at face value we would be planting lots of coppiced woodlands to encourage nightingales but it wouldn’t. They cling on to these as a last hope not actively choosing them as their preferred habitat. She demonstrates the same with the butterflies and suspects the same thing with collared doves.
- If you want to increase biodiversity allow herbivores on the land. They create a biodiverse ecosystem from a blank slate – just one species will do but if you have more then there will be an even bigger effect. One example given in the book is in Nigeria where cattle grazed with donkey’s put on 60% more weight because the donkeys graze the tough, upper portion of the grass revealing more delicate parts for cows. This also happens slightly closer to home on Dartmoor where the wild ponies eat what they like, leaving close cropped grass for other herbivores such as free-roaming cattle and sheep. What they leave behind is ideal habitat for marsh fritillary butterflies.
- Islands of wilding are not enough. We need corridors and more, bigger and better sites.
This is such a fantastic book, jam-packed full of interesting, slowly evolving rewilding observations. The big take away from it is that nature does it best; not the big, well-known conservation groups although they have all done other good things. It is their lack of ability to take risks and to be at the forefront of different ways of working that is quite frustrating.
All I can say is the winning book of the Wainwright prize in 2018 must have been excellent.