All wild creatures are indicators of the health of our countryside. Stable populations of fish or foul, mammals or insects, show that the countryside is in good heart. When species begin to wane, as so many have in the past two or three decades, it is a sure sign that things are amiss.

Now, as far as bats go at least, there is good news: many caves and caverns in the Yorkshire Dales, once thought to be home to only a handful of these flying mammals, in fact house thousands - and there have been unconfirmed reports of lesser horseshoe bats, not recorded in Yorkshire for over 50 years and not in the Dales for over 100.

These findings are the preliminary results of an on-going survey under a biodiversity campaign launched last year by the Yorkshire Dales National Park and led by Prof. John Altringham, from the University of Leeds.

However, there is a potential problem: these bats are not alone. Many of the caves they use are also a magnet to humans - the thousands of potholers who swarm to the Dales every weekend.

Fortunately - or so the early evidence suggests - the potholers and the bats live in peace together. But results of the research will enable the park authority to work with pothole clubs to draw up plans to help protect the area's bat populations and further develop voluntary codes of practice for the recreational use of caves and potholes.

Now this I like. Potholers, like climbers and committed walkers, tend to be as interested in conservation work as the professional environmentalists: after all, the countryside (or, in this particular case, the sub-countryside) is where they find their pleasure and it is in their interests to preserve it.

We should have more of this sort of co-operation because the more eyes there are on the alert for signs of damage to our habitat, the better it will be protected.