I have been carrying out some minor research – admittedly lacking real scientific rigour – into one of the hazards we often encounter when visiting nature reserves, namely dogs and in particular, the evidence they leave behind indicating that they have used the path. Linear transects along obvious routes into the reserves were undertaken. Counts of "evidence" were made at intervals divided into 100 metre sections.
Two sites, Totternhoe Quarry in Bedfordshire and Devil’s Dyke, Cambridgeshire, were selected for this study; similar results would have undoubtedly have been found on a local footpath near to my home.
It is apparent that the most hazardous area is not in or even close to the car park but several hundred of metres into the reserve. The fall-off in apparent activity occurs quite abruptly at about 800 metres beyond which conditions become relatively benign for the butterfly watcher.

- Totternhoe.jpg (64.94 KiB) Viewed 1147 times

- DDyke.jpg (71.58 KiB) Viewed 1147 times
As indicated, this survey would hardly stand up to Peer Review as many factors have not been considered:
Type of dog
The age of the dog
The age of the dog owner
Whether or not the dog is on a lead
Was the evidence left on the outward or return part of the walk?
... and so on
Nevertheless, it is hoped that you will have at least a little insight into one of the most frequently encountered hazards for the butterfly watcher. It might also be useful for Reserve Managers in helping them determine the best places to erect dog-waste bins; it would seem the car park is not necessarily optimal.
I take the opportunity at the start of a new month to wish my fellow butterfly enthusiasts a productive season.
Jack