One for the Potential list:
A great new paper has just come out in Global Change Biology by Sarah Jackson and Kevin Gaston: Land use change and the dependence of national priority species on protected areas. In what is simultaneously frightening and ecouraging is the observation that of nearly 400 Biodiversity Action Plan (BAP) species considered either to be globally threatened or rapidly declining in the UK (i.e., > 50 % decline over 25 years), 55 % were largely restricted to statuatory protected areas in the UK. These areas cover about 11.5 % of Britain’s land surface.
What’s amazing about this is that without these reserves, these (hundreds) of species would already be extinct (or very close to it) – if this isn’t one of the strongest arguments for reserves, I don’t know what is. Not only are reserves essential for maintaining populations of threatened species, their spatial connectivity is also highly influential on persistence probability (future posts on fragmentation coming).
Much of the planet has now been modified to the point where any sort of species preservation will necessarily require large, expansive, contiguous networks of protected areas. Jackson & Gaston conclude:
Britain has undergone particularly extensive land transformation, reducing many originally much more widespread vegetation/habitat types to scattered fragments, few of which can be considered strictly natural (Rackham, 1986). A proportion of these fragments receive statutory protection and intensive management, increasing the likelihood that species of conservation concern are restricted to such areas. This circumstance is not unique to Britain, being found in many heavily developed regions including much of northwestern Europe, although it is not so extreme in many others. Britain may, thus, represent a possible future scenario for such regions. Under such circumstances, it is not unlikely that many species if they are not already restricted to protected areas will become so (e.g. species confined to tropical forest habitats following deforestation).
Keeping things off limits from the burgeoning human population is therefore one of the major ways we can stem the tide of extinctions.