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The Floral Survey at Three Lakes

A very special lakeside wet willow woodland habitat with Royal fern understorey

The reasons for taking a floral survey as part of a palaeoecological study are three fold.

At the present time there are major concerns, world wide, but also specifically in Ireland, that biodiversity is being lost. This is happening at an alarming rate, and as described in other posts, there are several reasons for this. But a major part of understanding what has been, and is being, lost, is to find out what is there now, so biodiversity surveys are all the rage at the moment. Ireland has a specific organisation and website for understanding this - The National Biodiversity Data Centre - and data is being accepted from any genuine source - citizen science is coming into it’s own at last. The floral survey at Three Lakes will add in to this.

As a postscript to that first point there is also a scheme to register habitats across Ireland, and the original habitats defined by Fossitt (see here - pdf file) have since been replaced by a national vegetation classification ( see here - NBDC) which is managed by the National Biodiversity Data Centre. As well as determining the degree of biodiversity by surveying the vegetation, we will also be able to help define specific habitat types as we find them, and any variations that may be found.

A small selection of plants from the various habitats within the Three lakes area

More specifically related to palaeoecology is the fact that having determined the vegetation that exists at this place today, we can make use of this to understand the vegetation of the past.

We shall be examining the pollen record from the top layers of the core, and we can make the assumption that the vegetation growing today is not so very different - because we believe the habitat types have not changed - from what grew here a hundred or two hundred years ago. So we can then relate the pollen preserved in the bog or lake sediment with the vegetation that was producing the pollen. Not all plants produce the same amount of pollen, and not all pollen is preserved, so looking at pollen does not give a complete picture. But maybe we can fill in the gaps by understanding what plants grow together, so finding pollen of one plant can indicate that another set of plants were probably also present. This will help to interpret the fossil record and build a picture of the vegetation from that time. An added implication of this aspect is that we shall also have to survey the vegetation of the surrounding area, the valley sides, back west towards the watershed, and eastward into the gorge. That way we can gain an understanding of how pollen from further afield ends up in the sediment we are examining.

The third use of the vegetation survey is simply to provide a final stage in the historical record of the changing plant communities over time. At Three Lakes the sediment covers the last 16,000 years, approximately, providing a record that goes back to the end of the Ice Age. In the intervening time the vegetation communities have built up through various changes in climate - a warming after the ice, a severe cooling for a thousand years or more at the Nahanagan Stadial (otherwise known as the Younger Dryas), and then, in the Holocene, a warming to above what used to be normal, then slight cooling. And of course we are now going into a rapidly warming period.

The record will continue into the future and we can assume there will be some quite severe changes. The past record may help us to understand these changes, not because they have happened before, but as part of a continuing process.