Nature 2007 February

The Hills Are Alive with the Smells of Nature

2006 proved to be yet another ‘warmest year on record’. It was also amongst the wettest in recent years with thirty inches of rain. 2007 has so far continued in much the same vein. The outlook for February and March is for above average rainfall and whist it will remain warmer than average for the next few weeks March will turn colder with sharp winds forecast towards the end of the month. Another consequence of the increased rainfall over the past year has been the rising water table. For the first time since late 2005 there is water in the well and it is increasing by five inches a day. After a series of drought ridden years and assuming this recovery continues, this is good news for gardeners, farmers and wildlife.

Whilst humans may have the edge on other animals when it comes to intellectual capabilities, well usually, but when it comes to our ability to use or senses we come a poor second, not just to mammals but also to most invertebrates too. Take, for example, our sense of smell. Yes we can both appreciate the perfume of bluebells in springtime and find ourselves recoiling from the stinkhorn’s odour of decay in late summer, but the extent of our olfactory abilities is equivalent to viewing the beauty of nature in black and white without even the benefit of seeing shades of grey. Meanwhile for many animals odours produced by both plants and animals including man, provide them with the equivalent of a three-dimentional multicoloured world. During the next two months many of the animals we are familiar with in these parts will emerge or stir from their winter rest. These animals have a totally different view of the Hilltop Villages to us. For example, insects such as moths are able to detect hundreds of chemicals or pheromones, which create a route map that directs them from as far as thirty miles away, through obstructions towards others of their species. Honeybees use them to set out instructions to tell others how to find new food supplies. Amphibians such as frogs and newts detect ponds and streams and make for them cross-country style. Grass snakes are said to taste with their tongue but this is somewhat of a misnomer. What they are actually doing is collecting molecules of the essence from the air and transferring this to their olfactory organs in the roof of their mouth. From this they can determine what is producing the scent; friend, food or foe and how recent or how far away the source is. The raucous echoing grunts of muntjacs are often the result of one male straying into another’s territory. And what about the bluebells and the stinkhorns? Well they’re both at the same game. Bluebells abound in ancient woodlands. To ensure their continued survival they must emerge and produce sufficient energy from photosynthesis so they can flower before the woodland canopy blocks out the light. Fewer insects are around in woodland this early so the bluebell has evolved to produce its characteristically pungent aroma to attract flies and beetles. The stinkhorn has evolved to emit an odour similar to rotting meat as far as insects are concerned. Flies and beetles, which land on the fungi, get spores either stuck to them or may consume the fungi and the indigestible spores are similarly distributed. To us all such odours have a distinct but just a single smell. To the dog you encounter on a walk or one of his fleas you present a fruit cocktail in glorious technicolor which will ensure you have their attention.

So will spring be early or late this year? A clue to this comes from comparing the earliest and latest dates when particular events relating to certain indicator species occurred from year to year. For example, I have records of Hazel flowering between 29th Jan and 9th Feb, Snowdrops between 29th Jan and 3rd Feb, the first Bumblebees appearing between 26th Feb and 18th Mar and Ladybirds between 9th and 31st Mar.

Ponds are excellent places to see the transition of winter into spring. Around now they are typically dormant but even a small temperature increase can suddenly make them erupt into life. So for this month’s field trip visit one of the many ponds in the area.

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