The multiple-factor story expands to other contexts...
Now sustainable agriculture: the number of interventions seems to matter
As a reader of this newsletter you have very likely read something about our number-of-factors work. We have initially applied this idea to the number of global change factors: a greater number of global change factors leads to ever stronger effects on ecosystem processes and biodiversity; we have shown that in highly controlled lab experiments, and more recently also in the field (unpublished), as well as in a global data synthesis exercise. In every experiment or observational data we could detect the signature of the number of global change factors.
The second chapter of this work was to apply the same idea about the number of items to a different context, namely restoration. We hypothesized that a greater number of restoration management interventions would unlock greater benefits for restoration success, for example in the context of soil health. The initial evidence supports this notion, consisting of our own experimental work in the lab, but also that of others. This is interesting because the same basic idea seems to hold also in a completely different ecological context.
Now the third chapter has been opened with another data synthesis exercise, just out in Ecology Letters, a collaboration with the lab of Manu Delgado-Baquerizo (the study is first-authored by Luna Medrano). In this data synthesis, we looked at the effects of an increasing number of agricultural management practices aimed at sustainability. And once again, we could detect a signature of the number of practices: the more, the better for agro-ecosystem sustainability.
I find this super fascinating. It would appear that the number of items carries real meaning in ecology. The idea originally came from biodiversity-ecosystem-functioning work (B-EF), and in this case the items were plant species. This idea, which originated in the random-sampling from a pool protocol pioneered by David Tilman for plant species effects on ecosystem process rates, has now moved quite a bit to other contexts.
One may wonder, as I have before, if this idea of the number of items combined also applies in other area of biology, or biomedical contexts, for example. Or even more broadly across all of the natural sciences, so also in chemistry and physics. If so, what are the basic underlying mechanistic principles? Are there basic common mechanisms? What does this tell us about our world?
Let me know your thoughts on this.
A fascinating piece of research to read. One of the most interesting parts was the distinction you make between parts of the world where only a few sustainable practices will be enough to make a difference and those areas where many would be required. My question is about the latter - ie where many are required. Will any six do, as long as there are six of them? Does the grower need to know which practices need to be in the mix, or will any mix be OK, as long as there are many of them? A related question is what is your hunch about how the many practices interact? In a simple additive sense or more as a complex web? Thanks.