REWILDING

Herbivores at the core of ecological processes

I have just finished reading the book Rewilding by Paul Jepson & Cain Blythe (the illustrated edition, Icon Books 2021). It makes one rethink one’s whole understanding of terrestrial ecology. In summary, the book concludes that large herbivores have a major role to play in shaping the vegetation pattern across landscapes. However, because over much of the planet we have made large herbivores extinct, the current ecosystems we see as ‘natural’ are in fact no such thing. The book says that ‘rewilding’ should be about bringing back large herbivores to ecosystems, and thereafter allowing them to develop naturally; allowing the natural processes which have largely been lost. “Advances in ecological science have firmly positioned herbivores at the core of processes that produce vibrant ecosystems across all scales from the local to the planetary.” [page 137] In relation to this, I have noticed a contradiction in the approach taken to rewilding in the Scottish Highlands to that promulgated elsewhere in Europe: in most of Europe rewilding is about reintroducing large herbivores, whereas in the Highlands it is about removing them – or at least making them functionally extinct. I have argued for quite a few years that the vegetation pattern of the Highlands is one of the most natural remaining in Europe because the area retained a significant population of large herbivores (red deer) throughout the postglacial period; and for most of postglacial history the herds were unmanaged (although hunted), as described in my recent paper. Where else in Europe is this true? I have one cavil with the book, though, and that is that it does not recognise this contradiction between the Highlands and elsewhere. The book, in passing, accepts the narrative that high densities of deer in the Highlands are caused by the ‘hunting estate model’, and that there are too many deer as evidenced by the absence of trees. This seems to be an aberration that goes against everything else the book is saying! I would argue that reducing deer numbers for the sake of encouraging trees is not ‘rewilding’ as defined in the book, but instead it is humans expressing their will on the landscape to make the vegetation pattern accord with what ‘should’ be there. It is the opposite of ‘self-willed land’ and could almost be called ‘dewilding’. In the same way that the commonly used phrase ‘natural regeneration’ is based on ‘non- natural’ levels of grazing (by making herbivores functionally extinct); what is natural about this? The point is in effect illustrated in the book: it quotes research [page 83] suggesting that one area of Arctic Russia would have hosted a rich megafauna, with 1 sq km of land supporting: 1 mammoth 5 bison 7.5 horses 15 reindeer 0.25 lions 1 wolf This is mind boggling! – especially when compared with the measly 3-4 red deer/sq km being promoted by conservationists in the Highlands (low enough to encourage trees). My latest paper argues that, in fact, herbivore density is determined by food availability, and that upland vegetation in Scotland can support an order of magnitude more grazing than the exceedingly low level that enables trees to survive in the landscape. Hence the open landscape (too simple?!). March 2023

Dr James Fenton, Seil Island, Scotland www.fenton.scot ecology@fenton.scot

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