A large body of research shows that biodiversity loss can reduce ecosystem functioning.
You don’t say. Several years ago we half-heartedly attempted to summarize the literature here a couple of times. We’ve sort of given up on that of late: there’s just too much of it. But there is a fundamental problem with this literature…
…much of the evidence for this relationship is drawn from biodiversity–ecosystem functioning experiments in which biodiversity loss is simulated by randomly assembling communities of varying species diversity, and ecosystem functions are measured.
Fear not, though, help is at hand. The two quotes above are from the abstract of a paper bearing the following title.
The results of biodiversity–ecosystem functioning experiments are realistic.
Phew.
The paper cited before the `Phew’ says in the Conclusion: “Although we do not provide direct evidence for strong BEF relationships in real-world communities…”
Just so. These people are still at it after decades. The experiments are done in unreal environments where many plant species can flourish and the main stress is inter-species competition. In the real world most environments are not unstressed. In fact, where you really need ecosystem services, that is, in stressed environments, just one species can dominate. There is no competition: what remains is the single species best adapted to the prevailing stress. These people totally ignore the substantial ecosystem services provided by monodominance in `marginal’ conditions.
Examples are legion at the margins of water, salt and fresh: mangroves, giant kelp, Phragmites, turtle-grass, Pemphis woodland, lots of `marginal’ northern and southern forest, and much more besides. These can be vast areas where one species provides all the ecosystem services obtained from macrophytes. This vegetation is ignored by those fiddling around with multi-species experimentation.
The main lesson for arable farming is that multi-species experiments are a waste of effort. Most of the first cereals were taken into cultivation from monodominant stands of wild relatives. The main purpose of expensive and/or laborious tillage and weeding was a copycat of nature: the need to maintain the environmental stress under which wild relatives grew as monodominants (my guess the stress of seasonal fire to which wild relatives were adapted by their ability to self-bury seed).