MAMMALS

Page 1

4

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

Trans. Suffolk Nat. Soc. 37 (2001)


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.