The first snail of Spring
The first daffodils bloomed on 1st January in my garden, but the snails Cantareus (Helix aspersa as was) under the ivy were deep in hibernation in mid-February and look unlikely to emerge any earlier than normal. The mild winter could be more serious for hibernating bats and hedgehogs if their fat reserves run out before there are enough invertebrates to feed on.
The obvious consequences of climate change are to length of growing seasons and times of breeding, migration and flowering. There will be major consequences for species ranges, for farmers' choice of agricultural crops, and an alteration to the balance between crop pests and biocontrol agents. The range of parasites may also change - the snail hosts of human blood fluke may find areas of Europe, Asia and the Americas more to their liking while parts of Africa become too hot. If Southern Ocean temperatures increase two degrees further, locomotion of marine molluscs will be impaired,. Moreover, the landmass of Antarctica is a barrier to their poleward migration.
Secondary effects include increased precipitation and cloud cover, thawing of glaciers and permafrost, more frequent fires, sea levels rising 1-2 mm per year, and the increasing frequency and intensity of extreme events such as storm surges, leading to flooding of low lying areas and coastal erosion. The seas have absorbed 50% of carbon dioxide produced by human activities in the last 200 y, but by the end of this century, pH is predicted to fall from 8.2 to 7.7, causing problems in shell formation for molluscs and crustaceans - and for plankters such as coccolithophores, which form a literal carbon sink as their shells fall to the sea bed.
The changes in the next few decades are the unstoppable consequences of our past and present activities. Although events such as climate change may be regarded as having the inevitability of gradualness, they are fast enough that we can see the effects over a generation, as species ranges drift northward at 6 Km per decade and migration, flowering and egg-laying advance by 2-3 days per decade.
I am grateful to all, especially Villie Flari and Laurence Cook, who have contributed material for this issue. Please send contributions for the next (August) issue to me by mid-July. Contributions of articles, brief reviews, and news items (including items from non-malacological journals) are especially welcome. Please keep articles and abstracts 'as short as possible but as long as necessary' and avoid or explain specialist terms. Where appropriate, include a reference to a more detailed account, and an illustration.
Dr S E R Bailey
Faculty of Life Sciences, 3.614 Stopford Building, University of Manchester, Oxford Rd, Manchester M13 9PT, UK.
Email: bill...@manchester.ac.uk. Tel: 0161 962 2573.