concept of the threshold is key to explaining change and is something
to be avoided in terms of management. However, the term is not well
parameterised nor is it always capable of being used. This paper explores
the notion behind it and the research needed to make it useful.
assumed that the greater areas in the tropics allows for greater biodiversity.
This study of bats demonstrates that a strong gradient does exist,
and at two scales, but area is not the main cause of variation.
studies on gradients are not that common and the effects are therefore
not well known. This comprehensive study suggests more needs to be
done as well as putting forward some useful ideas on impacts of gradients.