Introduction to ecosystems
Introduction to ecosystems

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Introduction to ecosystems

5.3 The survival of Wicken Fen

We will now revisit Wicken Fen, Britain’s oldest nature reserve. The reserve is being managed artificially, in order to support multiple habitats, and by extension multiple species and multiple food chains. Those working on the reserve believe that without management the fen would be overtaken by bushes and trees, which would reduce the number of habitats, and support fewer species.

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Survival of Wicken Fen

Succession is an ongoing natural process. If humans didn't manage the fen, succession would continue, and much of the land here would be covered with bushes and trees. This would greatly reduce the diversity of habitats available, and therefore, the diversity of species. Management of succession is a key reason why biodiversity of this fen is so high.
Management is important at Wicken Fen, because it, in effect, halts the progression of succession at different stages. If there wasn't any management, succession would just continue through to the, what's termed the climax, which, in most places in the UK, is forests.
And what we're trying to do at Wicken is hold those different areas of succession so that we can have the whole range of the different habitats, from the open water through the meadows through the sedge fields and also the areas of scrub. And by doing that, that really enables us to have the maximum diversity on the site.
The sedge harvest is another of the key management tools used on the fen. By cutting the fen's sedge fields on a regular basis, succession is halted before trees and bushes can grow. This type of management is very intensive. It requires a considerable amount of time and labour. Maintaining the fen solely through such intensive methods is unrealistic. The cost alone makes it prohibitive. So the management committee at Wicken is also using other ways of halting succession. Large herbivores, like cattle, have been used for many years. Using grazing animals like these provides a cost effective and environmentally friendly way of maintaining open fen. More recently, a herd of wild ponies has been brought to Wicken.
The area, before the ponies were introduced, was covered by large trees and scrub, small bushes. We've done quite a lot of work manually cutting the trees down to try and revert the land. The ponies are here to keep on top of the work we've already previously done. And as they move through an area, obviously that will have an impact. So we should see quite a mosaic of habitats - sedge fields punctuated with grass meadows, reed fields, again, punctuated with sedge.
Grazers represent a more sustainable way of managing the existing fen. But even management techniques like this may not be enough to guarantee its long term future. One of the main threats to the fen is its situation in the middle of farmland. Unlike the fen itself, the surrounding farms have been drained so that crops can be grown. Drainage effectively shrinks the soil. This means the fen now stands at a higher level than the neighbouring land.
The site is perched somewhere in the region of two to three metres or more above the surrounding farmland, which means that when you're trying to manage a wetland in those sort of conditions, water is very difficult to keep in. You can't stack it up with the best will in the world, which has meant that much of the site is actually now surrounded with a waterproof membrane to keep the water in. So hydrology is a big problem for us.
Maintaining water levels is not the only problem the site is faced with.
Wicken is fairly close to a number of small villages. But it's also quite close to Cambridge, Ely, and Newmarket. And potentially, that number of people close on the doorstep could be a problem.
Potential threats like encroachment could have a devastating impact on Wicken Fen. Because it is so small, even contained disasters may wipe out a significant proportion of the reserve, in the process, eliminating habitats and species.
Really, somewhere like Wicken Fen at the moment can almost be described as a paper handkerchief, a tiny little area now in a sea of different types of landscape i.e. a very agricultural landscape. If we're going to try and maintain the species that we've got here, we really need to try and expand the fen and give greater scale for these species to actually live on so they can move out and spread and have a better chance of survival in the future. And as a result of that, the National Trust has drawn up this vision relief for Wicken Fen for the next 100 years. And it involves acquiring land around the fen, gradually restoring that back to some form of wetlands. And we hope to, over the next 100 years, create that much larger area which will act as the buffer for the fen, new habitats for wildlife.
This increase in scale means the reserve can support larger populations of species within a diversity of habitats. And these larger populations are less likely to go extinct. On the other hand, if the area of Wicken Fen isn't increased, it will be less likely to survive in the long term, seriously depleting biodiversity levels in the UK,
The significance of Wicken Fen is that it's one of the very few areas of fenland remaining in the UK. And it's home to a huge diversity of species, many of which can be found only in this type of fenland. If we lost a place like Wicken Fen, we would lose a huge number of species along with it. And the UK as a whole does not have a huge amount of biodiversity. And to lose a place as important as this would put a real dent in all of the UK's biodiversity.
If Wicken Fen was lost tomorrow, we would certainly see 7,000 species disappear from this part of the world. A number of those species are now incredibly rare in the UK, maybe one or two other sites. So we would see some species almost being pushed to extinction in the UK. And what we would also see, I think, with the loss of Wicken, is the failure of conservation. And if we fail at Wicken, it's really only time, then, before we fail everywhere else.
High levels of species diversity rely on several factors - a range of habitats, the preservation of food webs, and in the case of Wicken, management of the fen. The National Trust plan to increase the size of the nature reserve at Wicken accommodates all these factors and will increase the chances that the fens unique biodiversity will survive.
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Is this a case where human intervention is a positive factor acting on the ecosystems present? Would you consider the fen to be an artificial ecosystem – one that would not exist but for human intervention? Here are some questions raised by this video. Make brief notes on possible answers in preparation for the discussion later.

  • What are the factors contributing to high level of species diversity?
  • What is the significance of Wicken Fen?
  • What kind of ecosystems and habitats would result if Wicken Fen wasn’t managed by humans?
  • Does the need for biodiversity outweigh the need for natural succession?
  • What kind of management tools are used to managed Wicken Fen?
  • What would be the result if Wicken Fen was destroyed or lost?

Contributors to this video include David Gowing (OU), Joanna Freeland (OU), Adrian Calston (Property Manager, Wicken Fen), Carol Laidlaw (Warden, Wicken Fen), Martin Lester (Head Warden, Wicken Fen).

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