Why is habitat management necessary? Why can we not just leave nature to its own devices and let it regulate itself? Members of the public walking past a coppicing team in a woodland often ask why we have to cut the trees down at all – so why do we humans have to intervene so much in maintaining particular habitats, surely they all existed just fine way before humans arrived on the scene?
Of course, in a completely natural and fully functioning ecosystem habitats such as woodland, heath, scrub, meadow, ponds and marshes would exist in a complex mosaic and all maintain and regenerate themselves without the slightest input from a human. The thing is, the Britain we live in today is very, very far from being a fully-functioning ecosystem. We live in a land almost completely shaped and altered by mankind, not a square metre of it is untouched by our hands and as a consequence nature in Britain is not really itself.
Imagine the British ecosystem as a whole represented by a factory, let’s say a chocolate factory (why not?), it is full of hundreds of workers who all have a specific job in keeping the factory operational, each worker represents a species of animal or plant. We humans are not in the factory, we just stand outside eating the chocolate. Now if some of those workers start going off sick, or taking long holidays, or even handing in their notice and leaving, the factory is not going to be running as smoothly as it was. Let’s say that a large number of important workers all leave one day (perhaps their pay is cut) and no replacements can be found in time – the factory ceases production. We humans rather like chocolate though, so with the limited remaining workforce we end up running all over the factory trying to fill in all the roles that the workers who left once performed.
In the real world, those important workers in the analogy were in fact ‘keystone species’ – animals that once played a vital role in the British ecosystem but have, one-by-one, gone extinct. In essence we are now working with a broken landscape, there are still just enough species left to keep it running, but it is far from being the original natural state it was in at the end of the last ice age. Most of those keystone species are only extinct because we killed and/or ate them.
I do a bit of conservation management myself as part of a volunteer team, what I have come to notice is that a lot of the jobs we do are things that would once have been carried out (and much better) by now-extinct animals. A good example is heathland, this is a habitat that requires a lot more management than others as it is an open habitat that keeps wanting to return to a climax woodland. All heaths in Britain today are man-made, many relics of ancient commons or hunting forests, they have been kept open for centuries by people cutting and burning and grazing livestock on them. Heath is a habitat that is home to many species of specialist plants and animals (especially invertebrates) that cannot live anywhere else – they have evolved to survive in heathland communities. This suggests heaths have existed long before humans came along and kept them open – so what kept heaths from succeeding to woodland before people arrived in Europe?
Keystone species are the ones that made a big impact on the landscape and species around them – large herbivores and apex predators being the best examples, although there are exceptions. It is the big grazers that would have roamed ancient Britain which kept the patches of natural heath open, back then the land would have been a complicated mix of scrubland, mature wood, glades, grassland and heathy areas – although perhaps not the large expanses of heather we see today. The key species would have been Aurochs (the huge, wild ancestors of modern cattle), Boar, Bison, Elk and giant Irish Elk – and if you go back far enough then Mammoths and Woolly Rhinoceros would have been very important to the ecosystem of ice-age Britain.
I believe there is a theory that the reason many European trees species (such as Hazel, Birch and Willow) can grow back so well after coppicing is because they evolved alongside Elephants (or Woolly Mammoths) that would snap whole trees over with ease. I wonder though if Beavers had a part to play in that, they are renowned as landscape-engineers and they chew down many trees for the construction of dams and lodges. On the subject of Beavers, it is interesting to note that we are now having to perform the duties that they would naturally do in order to reduce flood-risk on our rivers and streams and also to increase river biodiversity. Blocking rivers upstream with logs and branches to slow the flow of water and keep more water in the catchment area is exactly what Beavers could be doing if they weren’t extinct (although it is good to see that we now have a few thanks to re-introductions).
Then there are the predators – Lynx, Wildcat, Bears, Wolves and Cave Lion – animals that would have existed at low density but would have kept the herbivore populations in check. Today we have to spend a lot of money controlling deer populations in Britain, they cause a huge amount of damage to forestry in particular but also cause problems for wildlife conservation. Although Fallow and Sika (Muntjac and Water Deer are less numerous) were introduced by us so are our problem, the native species could certainly do with efficient natural culling courtesy of a wolf pack or two – if only.
You could argue that the animals I am mentioning are creatures of the ice-age, an ecosystem quite different from that we have in Britain today and that surely, if humans had never been involved, many of these would have naturally gone extinct anyway due to the change in climate. The thing is, our environment and the species that live in it are still very much in a end-of-the-ice-age phase, evolutionary speaking, things haven’t moved on because we got in there and mucked things about before it had the chance. The floral and fauna assemblage is still much as it would have been 8-9000 years ago when Britain was covered in the post-glacial wild forest – just much depleted and minus all the cool big stuff. Plus if you look over the channel, mainland Europe still has Wolves, Bears, Lynx, Bison, Beavers and Boar – although admittedly hardly in the numbers or range they would be if humans weren’t here.
So when we are clearing Birch scrub from a heath and cutting heather to create open patches – those are jobs Aurochs and Boar could have been doing. When we are ‘re-wilding’ river channels – that is a job Beavers could be doing. When we are cutting swathes of reedbed to keep it a diverse sward – that is a job Elk or Tarpan (wild horses) could have been doing. When we are coppicing and cutting down trees to create glades and rides for wildflowers and butterflies – that is a job Bison could be doing.
It is a shame that some of these mighty animals no longer exist anywhere on Earth – Mammoths, Aurochs, Irish Elk, Tarpan, Woolly Rhinos – yet it is possible to use equivalent animals to fill the gaps; longhorn cattle and Konik ponies for example. There are still those other, still extant, species; especially the larger predators such as Lynx which do still exist and could, potentially, be re-introduced and carry out their roles in the ecosystem once again.
(cave painting is from Lascaux, France, depicting Aurochs, deer and wild horses)