CLIMATE CHANGE AND BRITISH WILDLIFE
Trevor BeeBee
Bloomsbury
2018
366 Pages
Hardback £35
ISBN: 978 147294 3194
Review by Peter Taylor
Charting nature’s winners and losers in a dynamic climate
When a book feels well-made, with quality illustrations and full references, I am inclined to forgive the price and forego much prejudice. Beebee strikes a very good balance, in contrast to some of the exaggeration and activism that I read from campaigners, some academics and much of the media on climate change. As with any major environmental change, there are winners and losers and the balance struck is to document both without the hype, and in some depth with up-to-date references to the scientific literature.
Beebee is Emeritus Professor of Evolution, Behaviour and Environment at Sussex University. He spans all of the wildlife and ecological fields succinctly, with chapters on plants, invertebrates, freshwater and terrestrial vertebrates, fungi, lichens and microbes, the latter of which seldom get much treatement. There are then chapters on communities, including coastal and marine; on future scenarios and models; and on conservation priorities.
Thankfully, the author understands the limitations of models and projections and the caveats required when making conclusions from sparse data. The climate of Britain has always been changing and Beebee is weak on the cyclic nature of such change, and there could be more about past temperature regimes, but he is strong on detail, both available data (and its gaps) and the care required for interpretation.
The conclusions are clear: Britain’s fauna and flora are responding to rising temperatures, particularly over the last two decades of the 20th century, but the changes are not dramatic. The British Isles is on the northerly limit for many species that require a continental climate, and at the southern limit for northern species, especially Arctic or boreal. Some plants and insects, especially moths and butterflies are expanding northward, with some new insect species arriving from the continent; and some northern species are contracting at the southern end of their range; plants and insects are also moving upslope. In general, northern range expansion is greater than southern range contraction – but we are talking mostly of tens of kilometres, perhaps 100km at the most for the mobile insects. Iconic northern birds, like snow bunting, appear more robust to southern contraction and there are new breeding arrivals, such as egrets.
The main years of warming were 1976~2006. Prior to that, there was a natural warming from 1900-1940, a cool period from 1940-1975; and since then, apart from a major El Nino in 2016, surface temperatures have remained relatively flat, but about one degree Celsius above ‘pre-industrial levels’ (prior to 1800). These decades have also coincided with decades of agricultural intensification and habitat loss, especially on hills, acid rain and nitrogen deposition. On the plus side, forestry policy has shifted dramatically toward diversification; wetlands, especially reedbeds, have been re-created; and grazing pressure on the hills has been reduced. Beebee is skilled at disentangling (where it can be done) the competing pressures necessary to identify the role of climate. For example, the southernmost habitat of the ring ouzel on Dartmoor has changed little, yet this species has contracted its range and lost abundance within it. A number of other upland species may be affected by drier summers, such as curlew, dunlin and golden plover, where the biomass of craneflies is crucial to nestling success.
Mild winters are also as much a threat to some species as a boon to others, as diseases and parasites may thrive as well as winter food supplies. There are mismatches in timing of prey species – for example, caterpillars coming earlier than hatching chicks of woodland species; newt predators arriving before frog-spawn can escape the gelitaneous envelope – but the effects appear marginal. All in all, ecosystems have been resilient to the one-degree rise over the past century.
What of the future? Here Beebee reviews the use of climate models and with a sufficiently critical eye, looking at methods of assessing species ‘climate envelopes’ and noting how early models took little cognisance of available habitats when predicting changes in range or abundance from temperature change alone. Again, there are expected losers in a world which may warm by another one or two degrees – for example, the snow-bed willow, a specialist of disturbed ground in the alpine zone; and there are expected expansions of range which will bring newcomers to the mix, for example purple heron and cattle egret. The best models are built upon species data for range and abundance changes over the past 40 years, with a judicial eye on other factors, such as agricultural practices.
I would like to have seen a treatment of natural cycles – of how white storks nested in Scotland during the previous peaking of the 1000-year cycle; or how the lake-dwellers of Somerset ate pelicans for breakfast eight-cycles ago. If this warm period (whatever balance of natural and human influence) is as extensive as the last, we may yet see the storks return to the UK. They have been seen prospecting and we already had a white pelican wandering around Cornwall last year! But, of those small number of modellers who have incorporated cycles, there is an expectation of a natural downturn – a combination of oceans absorbing more heat, and the sun putting out less energy.
Although Beebee shows how the major phenological changes have been slow and relatively contained with regard to community response, it is in the marine environment, where major ecosystems shifts have taken place, especially in the North Sea, with rapid replacement of cold water plankton, migration of cold-adapted fish, and consequent impacts on seabird breeding success. He notes, however, that the latter has also to be distinguished from over-fishing by industrial fleets such as the expansion of sand-eel fisheries, the major food source for kittwakes and puffins.
Finally, there is a chapter on how conservation strategies should respond. It includes the usual plea for hedgerows, joining up woodlands and extending reserves; the blocking of upland drainage, tree planting for flood control, fenland re-creation and managed retreat in coastal areas. It could be a bit more inclusive of ‘rewilding’ schemes and the potential for rewilded areas to create more robust ecosystems, but I am glad to see that renewable energy gets a balanced treatment, including recognition that some technologies can have disbenefits for wildlife.
This is an even-handed, dispassionate look at the current level of knowledge and expectations. I thoroughly recommend it for its breadth, clarity and scholarship.