MANY people recall a countryside populated with a wider range of wild plants and animals, than can be seen today. Scientific studies of biodiversity prove that this is more than just nostalgia; there are fewer species surviving.
Changing agricultural practices are partly to blame, said Professor Phil Grime of the University of Sheffield. The dominance of fewer species through the use of fertiliser and simple rotations, and excessive soil disturbance are examples.
But scientists disagree as to whether or not declining biodiversity is necessarily a bad thing in terms of a sustainable ecosystem. Some of the most ancient habitats such as heath and bog contain few species, he explained.
"That said, diversity is important as part of our national heritage and regional identity. There are ways that agriculture could help protect diversity – for example, by including specific weed seeds on set-aside to feed certain endangered birds."
Climate change will affect biodiversity. Extreme weather will reduce species numbers, but this could be offset by new warm temperature species invading the south east from the rest of Europe, suggested Prof Grime.
US research is testing the theory that mixed plant populations may be better able to survive weather changes than single species arable systems. Early results indicate that greater biodiversity is more resilient up to a point – but Prof Grime commented that single species systems may be better able to bounce back when conditions revert. "It seems as though the dominant plants in any ecosystem have the most impact – and not necessarily the number of different species."