Letter: Species counts can fail to capture biodiversity

From David Barden, Llantrisant, Mid Glamorgan, UK

From

25 May, p 36

Having read your piece about how to measure biodiversity, it is worth remembering that although the species concept is immensely useful, it does have its limits. This is because species descriptions, in order to be practical, have to encompass a lot of variation between individuals, both in their outward characteristics and their genetic codes.

For example, species in the marsh orchid genus (Dactylorhiza) readily interbreed to produce lots of fertile plants spanning the whole spectrum of characteristics. In such cases, a simple species count can’t easily capture the true diversity present.