IS WILDLIFE REVEALING CLIMATE CHANGE?

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IS WILDLIFE REVEALING CLIMATE CHANGE? ROGER TABOR Thank you very much to Martin Sanford for inviting me along to talk and to chair this conference as well. The conference is called ‘Some Like it Hot’, and current climate change indicators seem to point to Global Warming as a reality. The last 15 years in the UK have been exceptionally warm. The outlook is certainly not encouraging and the further the prognostications go the worse it appears. For many the only consolation is encapsulated in: “it may not be too bad for my lifetime but heaven help the next generation”.

However, the precept underlying this conference can be realised in another phrase: “every cloud has a silver lining!” We were asked as speakers to try to reflect that counterbalancing reality, for some species will certainly benefit with changing conditions. The Guardian recently published some pictures created to look at what the paper suggested could be Britain in 2020. They showed South American parrots flying from palm trees across the Cam, with crocodiles below beside punting students. However, Tim Sparks quite rightly pointed out that bridge would probably not be at today’s level as shown, because by the time the flora and fauna have changed that much the water level in East Anglia, and specifically in Cambridge, is going to have risen dramatically! The Fens and the Broads would have a different appearance to today.

I am chairman of The British Naturalists Association (BNA), the national body for naturalists. It was founded 100 years ago by E. K. Robinson who also started our continuing Phenological Survey. The BNA’s centennial conference was held at Cressing Temple in May and the diversity of opinion on how we interpret Global Warming was clearly demonstrated by the differing viewpoints of Bill Oddie and David Bellamy who both spoke about the issues.

That conference was held in the Cressing Temple Barns in conditions that seemed almost as cold as it could be in an English May, that is until Global Warming changes and we suddenly lose the Gulf Stream. In such circumstances Britain could become colder while the rest of Europe becomes hotter. We could find ourselves very cold while everybody else is very hot.

Our geographical position makes it harder to predict with certainty climate outcomes.

However, climate change does not occur in isolation, and other factors are significant at the same time. The future is looking really gloomy for specialist species, because even without further Global Warming anything that causes disruption can cause problems where their habitat is fragmented. For example, the tiger with very specific requirements is finding it difficult to survive while the generalist domestic cat which has gained distribution around the world by our movement over time has less specific requirements.

For most species oceans have been barriers. One alarming trend for the future is tied to our global mobility. The number of species that we introduce, such as Oxford ragwort, has escalated and will continue to do so as climate changes as we change our gardening habits as it gets hotter. There will be more species that can migrate into the countryside. Scorpions may not stay on the Central Line platform at Ongar, but may go inter-city! Not all introduced species are as charming as grey squirrels (even though they supplant the red Trans. Suffolk Nat. Soc. 42 (2006)

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squirrel). Naturalists tend to ignore some of the other wildlife we’ve introduced with our movement around the world, like syphilis. Both black rats and the plague bacillus that was spread by them are species that most people would prefer not to re-establish. Both were spread by human travel, and both flourished in the warm medieval period at the expense of the human population in Britain. They both like it hot! Similarly malaria was then common in Britain, the parasite spread by mosquitoes, both our current native species but probably also the Anopheles Mosquito. It is assumed the future risk of malaria even returning to the levels of the 18/19th centuries would be low due to the lack of extensive marshland habitat that has been drained.

Confidence in drainage cannot be sustained if sea level rises become as rapid as some projections suggest. Confidence in health service controls would be undermined if changes occur rapidly and globally cause chaos.

Hardly anyone looks upon disease organisms as part of the planet’s diversity of species, because they affect us negatively. Many are loath to consider rats as wildlife species for the same reasons. Yet anyone making these distinctions are doing so because inherently they do not see us as part of the natural world. We do need a precise understanding of our relationship, we are part of the planet and the one thing that Global Warming is going to remind us about is how much we are a part of the planet.

Everything on this planet is ultimately entirely dependent on the sun. It enables plants to photosynthesise, and energy passes to herbivores and then on to carnivores. Global Warming is not something that has only happened in the post Industrial Revolution period, one of the less appreciated realities about Global Warming is that it enables us to live on this planet at all – it is essential for us to exist. When light reaches our world, some of it passes through carbon dioxide in the atmosphere and through some of the water vapour, and warming occurs. The light continues on until bouncing up off the earth as infrared, hitting again onto the same gasses and ending up as a thermal blanket around the world. If it wasn’t for that the planet’s surface could be about -18°C. So Global Warming is necessary, but how much is the critical factor. The greenhouse gas that has most effect is carbon dioxide. The Inter Governmental Panel on Climate Change is concerned that suddenly temperatures are rising well above past levels and we’re alarmingly facing almost exponential rise.

The changes have been concurrent with the sudden release of carbon dioxide and some of the other gasses since the Industrial Revolution. In the Carboniferous Period gas and shales were laid down over millions of years and in 150–200 years that carbon is being released as carbon dioxide. The stored photosynthetic products are being oxidised and released in a remarkably short time. It is suggested that by 2100 the carbon dioxide level in the atmosphere will have doubled.

The earth’s surface temperature has fluctuated considerably over the last thousand years, yet the rise over the last 200 is abrupt. The World Meteorological Organisation compared findings from research on tree rings, coral, ice cores, lake sediments and found the different sources all revealed a profound cooler period across the 17th century in the northern hemisphere, in accord with the snow scenes painted by Dutch Painters at that time. In contrast

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the medieval period was significantly warmer. In the 17th century the growing season was one to two months shorter than now. We know that a lot of glaciers reached their maxima within our knowledge of recorded distances.

There are records of Alpine glaciers blocking roads and running over villages.

Professor David Bellamy and others have stressed that natural cycles occur over time. How much of recent changes are part of a long natural cycle and how much caused by the recent burning of carboniferous fuels is debatable.

Yet it is unambiguous that we have released huge amounts of carbon dioxide over the last 150–200 years.

While the Inter Governmental Panel on Climate Change have viewed the outcomes from a range of computer models, the projections of which may vary, they all point in one direction. Carbon dioxide levels and global temperatures are rising. The northern hemisphere seems to be rising more than the south, as in the north there is more landmass than in the south, with a thermal difference between land and sea.

Sea levels are rising, much due to volume change as the large body of water becomes warmer, and melting ice will contribute. The permafrost then becomes less, with as a result that far more methane added to the Global Warming blanket.

BNA Phenological Survey If you keep a wildlife diary, as I do, you become tightly attuned with the seasons and this in turn helps with identification. However, it is no use gathering information if it is not going to be used and interpreted. The BNA has gathered a lot of seasonal biological data in its Phenological Survey from 1905 to the present day. For our centennial, data was collated – and also BNA collaborated with Dr Tim Sparks, who incorporated 22,000 pieces of information from the BNA into the UK Phenological Network, and also kindly produced graphs from BNA data.

The BNA data revealed a direct relationship between warmer mean December–February temperatures and the flowering season of Lesser Celandine Ranunculus ficaria getting earlier (a one degree temperature shift tied to a ten day reduction). The mean flowering date of Blackthorn Prunus spinosa flowers some seven days earlier per one degree rise. Wood Anemone Anemone nemorosa too flowers earlier in warmer conditions, some four days per degree. The data for Swallow arrivals had a greater scatter than the plant species closer tie to UK temperature, which is be expected for long distance migrants. Nonetheless, warmer temperatures were linked to slightly earlier arrivals. So phenology is really just as straightforward as ‘doing a Gilbert White’. You spot the first primrose, first lesser Celandine, hear your first cuckoo etc. and, if the seasons shift with climate change, then we have a very sensitive and direct marker of changes. Wildlife really can reveal climate changes.

Swallow departures are getting later as Autumn falls back, and as the Spring is getting earlier, our overall growing period extends. It’s not the same for everyone though, because I live on the coast I am more buffered by the sea unlike inland Essex which has more of a continental climate with more

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noticeable sharp frosts. So as you go up through Britain what is correct for your local phenology isn’t the same as for the national phenology.

Looking into the future the general scenario is not good, globally becoming increasingly catastrophic. The IPCC predict massive global average temperature rises of 1·4–5·8ºC across this century, which are irreversible even if we didn’t burn anything else as of today.

The figures for Southeast England predicted by the Hadley and Tyndall Centres show rising sea levels (26–86 cm), but that the reality will be worse due to surging (anything from 2–90% increase). Summers are predicted to follow the current trend and continue to be hotter, while winters are anticipated as wetter and more turbulent with up to 90% less snow.

While Europe continues to grow hotter, there are predictions for the slippage of the Gulf Stream happening after the end of this century, suddenly reversing the trend for the UK. Are there advantages to Global Warming?

As shown above there is a reasonably direct relationship between biological events for a species and temperature. Current distributions of species reflect their optimal condition requirements. When the fauna and flora of one county like Suffolk, or of a country like England is considered, then as climate changes so will its balance of species.

Selfishly one gain directly to ourselves is that the UK winter human death rate could drop by 70% by the middle of the century, for we currently have the highest rate in Europe. Gardeners with extended growing season for plants, particularly in Essex, Suffolk and Norfolk, will increasingly switch to drought resistant, high temperature preferring plants. In the short term suburban East Anglia will increasingly support Mediterranean species in gardens, and then as successful escapes. Our current populations of wild “Mediterranean” plants including Shrubby Seablite Suaeda vera (which is particularly found mainly on the coast of East Anglia in Britain), Sea Heath and Butcher’s Broom appreciate our existing temperature-buffered conditions, and require September daily mean temperatures of 14·75ºC. Some plants like the Dwarf Thistle Cirsium acaule, that flourishes at Grimes Graves, and currently across southern England, need a July mean above 16·5ºC. If the edge of the distribution range of Dwarf Thistle moves north it will reflect that the limiting temperature has shifted north.

We will be able to observe damselflies and dragonflies gaining a prolonged laying and breeding period. Houseflies will benefit too! Some UK Lepidoptera particularly benefit from warmer conditions, such as the Wall Butterfly Lasiommata mega. The Pine Beauty Moth Panolis flammea has been demonstrated to have a direct relationship between its fecundity and temperature, as the greater number of degree days over 7ºC so the number of eggs laid increases. In this species, whose natural host is the Scots Pine, both its adult emergence from the pupae and its egg laying are very vulnerable to the prevailing weather conditions in March. The Pine Beauty has become an economic pest of the lodgepole pine plantations in Scotland, so the temperature benefit to one species has been at a cost to another.

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Cutting back on damage For naturalists with an interest in sustaining ancient woodland management, the use of coppice and pollard wood is in the current growing cycle, and consequently has no net effect on atmospheric carbon dioxide. Europe’s (including the UK) woodlands absorb nearly a third of the continents emissions. Keeping ancient coppice and pollard woods is much better than new planted woods, for cleared soil has been found to release more carbon dioxide than young whip trees can absorb over 10 years.

Redundant water mills and mill sites are being encouraged to produce electricity, which also benefits wildlife by habitat enrichment as mill sluices can control water levels to retain better summer levels. Just by growing and eating locally we can help counter the trend to global warming as a quarter of the UK carbon dioxide emissions has been attributed to the importation of food.

Conclusion Phenological data is proving to be a sensitive indicator of climate change, and, although climate fluctuates over time, the current period is one of abrupt global surface temperature rise. Temperature sensitive species’ population distributions will shift, but human-mediated global transposition of species and human fragmentation of habitats will be expected to favour some species at the expense of others.

References BNA’s Centennial Conference Issue, Country-side, The British Naturalists’ Association. Winter 2005/2006. Vol 32, No 4.

Houghton, J., Ding, Y., Griggs, D., Noguer, P., van der Linden, P., Dai, X., Maskell, K. & Johnson, C. (2001). Climate Change: The Scientific Basis.

Intergovernmental Panel on Climate Change. Cambridge Univ. Press.

Valentini, R. (18 Oct. 2002). CarboEurope; Can Forest Mitigate Climate Change? European Commission. Valencia.

Watt, A. (1985). The Ecology of the Pine Beauty Moth in Commercial Woods in Scotland, in Trees & Wildlife in the Scottish Uplands, Ed: Jenkins, D. Institute of Terrestrial Ecology/NERC 79–87 World Meteorological Organisation (2000). Organisation Statement on the Status of the Global Climate. WMO-No. 913.

Roger Tabor Chairman of The British Naturalists’ Association B.N.A. P.O. Box 5682 Corby Northants NN17 2ZW www.bna-naturalists.org chairman@bna-naturalists.org

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