MAMMALS

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Suffolk Natural History, Vol. 37 MAMMALS PAUL BRIGHT

I have worked for the Mammal Society for many years but during today’s presentation I will be speaking as myself and not as a representative of the Mammal Society, English Nature or the Peoples’ Trust for Endangered Species. I want to make the case to you as to why re-introductions, particularly the re-introductions of mammals are a jolly good thing and why they are not in any way ‘playing God’. I want to try and convince you that re-introductions are not just good for the mammals themselves but in fact offer multiple synergistic benefits to much other bio-diversity for the restoration of our heritage landscape.

The history of mammals in Britain is a long litany of extinctions and decline. The brown bear was one of the first to go in the 10th century at the latest, the lynx disappeared before that, the beaver disappeared soon after bears and wolves went in England and Scotland a few hundred years later.

Many of the species I am going to talk about today have declined greatly in distributional range even if they have not become extinct.

I think it is worth taking a step back to consider just why it is that so many of our mammals have declined. One important thing to remember is that mammals can occur at high density - they are often very thick on the ground compared to birds of a similar body size. An important implication of that is that for mammal populations to be viable they will usually have to occur at high density locally. This means that mammal populations are especially vulnerable to anything that reduces their normally high density and are therefore in danger of extinction when they are at low density. Since most of our mammals do not have wings they are not as well equipped to recolonise sites as birds. Also many mammals are phylopatric, ie they like to remain in the place they were born. So in general mammals are not predisposed to become great colonisers of habitats that become newly suitable. As 12% of Britain is urbanised with many congested and busy roads this also has an impact on the natural recolonisation of mammals. We know that if habitats are fragmented it produces small isolated populations which are vulnerable to extinction, especially in the face of fluctuating climate Therefore it is necessary to make attempts to redress the balance by translocation and re-introduction programmes.

So how do we decide which species to assist? My first slide is the mouseeared Bat. This is Britain’s last mammalian extinction. It has been extinct for about 10 years but had always been on the edge of its distributional range in Britain. The climate and habitat in Britain have not been suitable for this species for many years so maybe some would say it would be wise to just give up on this species as it should only just be here naturally anyway. I feel that this attitude is completely wrong, I feel we should never give up even on species on the edge of their range. I think this for two reasons. Firstly it would be a very brave man who would predict exactly how climate will change in this country. It may be that in 10 years time our climate will be more suitable for the mouse-eared Bat. It is also true to say that quite a lot of our flora and

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fauna are on the edge of their distributional range in Britain and if we abandon the mouse-eared Bat it sets the precedent to abandon a whole host of our other flora and fauna.

One of the first re-introductions of recent times was of the otter, or to be exact not really a re-introduction but a re-stocking programme of otters that were already present but at very low density. It is almost certain that the restocking of otters to East Anglia saved the otter population. The otter programme was well monitored by the NCC and the Otter Trust. For example, the first release group was radio tracked so we could monitor the distance travelled by the otters after their release. However, subsequent groups were released more covertly and this presented problems with trying to get data on the natural recolonisation of the otter. A similar problem occurred with reintroductions of barn owls. This illustrates that re-introduction need to be carefully monitored and should be nationally co-ordinated. Monitoring and proper surveillance of re-introductions is one of the key features in the International Conservation Unions Guidelines to Re-introductions.

Another example of a mammal that has been re-introduced in Britain is the dormouse - this is a mammal that is particularly ‘extinction prone’. It lives naturally at low population density, it is arboreal, i.e. tree dwelling, and it is small and for these reasons it is most unlikely to be able to recolonise across tens of kilometres of arable wasteland. This map shows the decline of the dormouse in Britain. There are only three known populations in the north of England and apart from that the dormouse has gone from six counties - over half its distributional range. This decline took place in just over a century. It is unlikely to recolonise of its own accord. Therefore there is the beguiling prospect that we could re-introduce the dormouse into the areas from which they have gone. However, we have shown through a long series of studies that re-introductions are not always straightforward, even when the should be. For example, we must confine them for a week to 10 days in a pre-release cage to allow the animals to accustom to a new habitat. Dormice used to be kept quite commonly as pets and they breed quite well in captivity, but dormice who have been born in captivity tend to perform considerably worse with a 22% survival rate in comparison to a 45% survival rate for those bred in the wild.

One of my students, Jenny Armstrong, set out with video monitoring equipment to find why this was and she concluded that those who paired up in captivity tended not to like their mate as much as those who paired up in the wild and tended to separate on release. In addition to this they seem to be poor at recognising when predators are around. So the price for captive bred dormice is divorce followed by death! However, in spite of this the reintroduction programme for dormice is going quite well and the one to north Suffolk this year has certainly been successful, with some 80 animals at that site from the 32–34 that were released in June.

Although the map shows seven successful re-introduction sites these are isolated populations and it could be argued that this is just cosmetic conservation. Will this really result in wider colonization of the countryside?

Let’s look at what has happened at the first re-introduction site, where we began releases in Huntingdonshire in 1992. They were released in the top

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Suffolk Natural History, Vol. 37

corner of a wood and for the first year they remained more or less in this corner but now they have reached right through the 200 acre woodland in all directions. There is now the prospect that the animals will be able to move along the hedgerows and into adjacent woodlands. This has made people think about re-establishing hedgerows coppicing and the planting of new woods.

Thus the re-introductions have added impetus to the cause of habitat restoration so benefiting not just dormice but many other species as well.

An animal that has been disgracefully treated in Britain is the pine marten.

It wasn’t protected until 1988 under the Wild Life and Countryside Act despite the fact that it had suffered huge declines. This slide shows just how common the pine marten was throughout Britain in 1800. By the time of the Great War the distribution of the pine marten had been severely reduced. It survived just on the far north west of Scotland and in some pockets of Northern England and North Wales, in fact I think it’s very lucky that the pine marten survived at all. So what caused this decline? Its decline was intimately associated with the rise of the game bird shooting estate and intensive keepering and trapping which was at its height just before the Great War. Today it is the game keepers that are under threat of extinction and there has been a considerable rise in suitable habitat for the pine marten. However, despite the improvement in these conditions there is no evidence that pine martens are recolonising, but we do know that re-introductions of pine martens can be successful. In Galloway in South West Scotland the Forest Commission made a reintroduction of the pine marten in the mid-1980s and showed an increase ten years later from the six released to 35 adults, but unfortunately the martens had only spread over an area of about 11 km. It would seem obvious therefore just to embark on a programme of re-introductions, but just as important as their viability is what the human populations response to the programme is.

For this reason it is necessary to consult with the various groups who will be affected by the re-introductions. In one such consultation where 1,000 questionnaires were sent out 90% of those returned by the general public showed support for pine marten re-introductions and, more surprisingly, we found that the majority of farmers and 65% of game keepers were also in support of re-introductions. This represents a huge change in attitude to carnivorous mammals in Britain and a possible useful source for cash for conservation. Not only were people happy to see re-introductions but they wanted them to be in their area so that they could benefit. from their reappearance. These were some of the comments in favour or releasing pine martens - ‘It might get rid of grey squirrels, ‘they make good hats!’ etc.

Mammals seem to be of more interest to the general public than other species.

The number of articles in the press about them is disproportionately larger in comparison to the number of articles about birds. Similarly, if we look at how many questions are asked in Parliament about mammals as compared with plants and insects we find that this is also disproportionately high. Mammals therefore are becoming ‘flag ship species’ that can be used to help the conservation of many other species and encourage people to restore habitats which can benefit the lower profile species as well.

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However, does that support extend to species such as the beaver? Scottish Natural Heritage are now going a head in a fairly timid way with the reintroduction of the beaver to Scotland. There are lots of reasons people give as to why we should not re-introduce beavers. The first being that there is not enough habitat support the beaver and the second that if beaver are released into small habitats they will create chaos and wreck it, causing landslides like those in the Alps. I think that these two arguments can be turned on their heads. They are in some ways the best arguments in support of bringing beavers back. We can use the fact that there is not enough wet woodland habitat in Scotland to support beavers at present as an argument to restore woodland. It maybe that the way in which beavers change the habitat is better in the long run any way - the beaver may know best.

Scotland is the largest wilderness area in Western Europe, surely there must be room for some of Europe’s larger carnivores in parts of Scotland? Just think how popular these larger more charismatic animals would be and what sort of impetus that would give to conservation. Most of the wilderness in Scotland is forest or sheep pasture, both or which are not that profitable, so it could be argued that there is a strong economic case for abandoning parts of the upland for the creation of a Scottish Game Park.

In conclusion I think it’s high time we thought about conservation in Britain much more in terms of restoration - turning the clock back rather than just retrenchment in isolated nature reserves. I think we should be considering the management of the landscape as a whole and I think that mammals are a key way to make that management successful. (text prepared by D. K. and M. N. Sanford from a recording made at the conference) Paul Bright School of Biological Sciences Royal Holloway College Egham Surrey TW20 0EX

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