Biodiversity / Ecosystem Function
It has become routine in ecology to assume that biodiversity is, at
least to some degree, responsible for the functioning of ecological
communities. This notion is now the foundation of a major argument in
favour of conservation, though some do question it. As usual, the
extent to which it is true critically depends on the precise
definitions used for both biodiversity and ecosystem function. If we
define biodiversity as the system’s total functional information, then
function rather obviously follows. For this reason, we believe the
ideas presented on this website cast a strong light on the Biodiversity
- Ecosystem Function debate.
Below we show one of the most comprehensive BEF relations, generated by
simulation of ecological communities, to date (Fung et al. 2014 in
review). The graph shows the effect of gradually removing 'species'
(from right to left on the x-axis), from a system of originally several
thousand (though only the simulated 'fish' species are removed).
Clearly there is a systematic relationship between the production rate
(growth and reproduction of fish) and species richness. However,
production rate is a single and rather crude measure of ecological
function and it is not surprising that in this measure, we see evidence
of considerable functional redundancy among 'species'. What is really
happening here is that as species are lost, others take up the workload
of production in compensation, but gradually the extra workload for
each of those fewer and fewer remaining species becomes relatively
greater - they fall behind in their compensating and the curve dips
down. This has little to do with information, but that is because it is
so crude a representation of both biodiversity and function. We would
like to develop a more sophisticated simulation, but that currently
awaits the necessary funding.