Do we need to learn to be more welcoming of nature’s migrants?
“We are at a point in recent geological history where the rate of human-induced climate change will far outstrip the ability of species to adapt successfully, especially when the resilience of nature has been reduced by habitat loss, non-native species introductions and over-exploitation. The disruption to the web of life is a threat not just to wildlife, but to the lives of people around the world.”
The report sets out evidence that wildlife of all kinds will be challenged because of climate change, and it says that protected areas and nature reserves will be vital in helping wildlife cope with a changing climate, which is something that many UK wildlife charities will agree with. For UK birds, for example, higher rainfall will adversely affect bearded tits, capercaillie and shags, and warmer temperatures in southern Europe will result in habitat loss for Dartford warblers. But Clarke says that it’s not all bad news from the RSPB perspective, as new bird species have begun breeding here, such as little egrets, black-winged stilts and little bitterns.
Clarke also raises the issue of whether we need to be both less precious about the idea of native, and much more welcoming of nature’s migrants:
“The wildlife we typically accept as being part of our ‘native’ flora and fauna is moving, and new species are arriving as colonists, partly driven by climate change. The assemblage of species we consider ‘native’ is therefore in a state of flux. We cannot arrest the changes, so to aid adaptation it will be important to enable species to colonise new areas via provision of sufficient, suitably-protected habitat, in areas that will become more climatically suitable over time.”
This idea is also part of what Fred Pearce argues in his book ‘The New Wild: why invasive species will be nature’s salvation’. Pearce says that keeping out non-native species looks increasingly flawed as a strategy and that we should celebrate their dynamism and the novel ecosystems they create. Pearce thinks that, in an era of climate change and widespread ecological damage, we should be finding ways to help nature regenerate, and that embracing this ‘new wild’ is our best chance.
Clearly, not everyone will agree with this open, liberal approach, and there are other, considered points of view. In all this, it’s necessary, perhaps, to distinguish between the invasive, and the merely non-native: that is, between those species that are here causing trouble, and those that are just here. Invasive species can be plants, animals, or other groups such as fungi or algae that cause disease or pest problems, and the RHS says that, after habitat destruction, invasive non-native species are the most serious threat to global biodiversity. It says that, in the UK, there are now 1402 non-native plant species, with 108 (8%) of these considered as invasive. Internationally, the database of such troublesome species is managed by the International Union for Conservation of Nature, which now lists 3,163 such plants and 820 animals. Based on this, the EU looks set to approve a list of 37 plant and animal species that member-states must eradicate where possible. Mercifully, this does not include John Wyndham’s triffids, that ultimate invasive species.
Non-native species are those that occur outside their natural range due to direct or indirect introduction by humans, and where the introduced species persist in natural or unmanaged habitats, they are termed ‘naturalised’. It is obvious that many naturalised species do not cause a problem; however, if they spread and out-compete native species they can threaten ecosystems, habitats, or the existence of native species themselves, and give rise to environmental damage and economic cost. One problem is that many non-native species can take a long time to become invasive, and many of the plants now considered invasive have been growing in the UK for over 100 years without causing a problem. Where they are a problem, however, they can be expensive to eradicate and it can take a long time: for example, at least ten years might be needed to eradicate giant hogweed, and three to four years to get rid of Japanese knotweed. A recent Economist article: Invasive Species – day of the triffids (which surprisingly doesn’t mention climate) argues for a measured and pragmatic approach to non-native species. It quotes Chris Thomas, a biologist at the University of York, who has calculated that of the UK’s 677 most widespread plant species, 68 were introduced by humans before 1500 and another 56 after that date, with not one of these introduced species ranking among the 50 most widespread plants in the country. Even Himalayan balsam is so rare that it barely makes the list. This is, of course, to take a national view, whereas all politics (whether about plants or people) is local and Himalayan balsam has to be tackled wherever it is found.
As I hinted at the outset, there are some parallels in all this with the current debate about the migration of peoples, although there are clearly important differences as well. For example, some of the language regularly used in relation to plants and animals cannot be used about people. But it’s possible that a discussion of the migration of plants and animals, and how tolerant we should be of the benefits and problems they bring, might ease a consideration of the much more difficult topic of the immigration of people.
Royal Horticultural Society (RHS) Invasive non-native species http://ow.ly/Wauus
Pearce F (2015) The New Wild: why invasive species will be nature’s salvation. London: Icon Books
RSPB (2015) The Nature of Climate Change – Europe’s wildlife at risk http://ow.ly/Wauq6
The Economist (2015) Invasive Species – day of the triffids http://ow.ly/Waulx