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Behind many efforts to make agriculture more sustainable is the idea that our farming systems need to be more like nature. According to agroecologist Miguel Altieri, “By designing farming systems that mimic nature, optimal use can be made of sunlight, soil nutrients, and rainfall.” This strategy arises from a long history of thinking that there exists a “balance of nature.” This idea has greatly influenced how we look at nature1 and agriculture. In the latter case, it drives much of what is done in organic farming and agroecology, but also finds its way into no-till farming. Nonetheless, it is false, and because it is false we can abandon the restrictive “nature knows best” argument in designing agricultural systems. Instead, we can improve on nature.
The “balance of nature” view and it derivations assume that ecosystems, as integrated communities, maintain themselves in an equilibrium if undisturbed by man. The equilibrium is maintained through governing rules, emergent properties, and self-organization within ecosystems. These properties act not just on the local populations, but on wider communities. Pests, predators, prey, and herbivores are kept in check by complex interactions between species and by a specific mix of species (biodiversity).
It is by these processes and properties that ecosystems have come to be thought of as analogous to organisms, with their own immune systems and other self-regulating mechanisms. In this model, every species has its function, and every interaction is essential for maintaining the overall working balance of the ecosystem.
Such thinking can be traced back to ancient Greece, and was supported by notable ecologists like Eugene P. Odum in his Fundamentals of Ecology (1953), but there have been critics. Henry A. Gleason (1882-1975) rejected the “super-organism” description of plant communities and instead suggested that the makeup of these communities was greatly influenced by chance events, which, within a locale, could result in very different communities; there was no balance, no climax state toward which all of the communities moved.
Other critics have been more forceful. Conservation biologist Michael Soulé writes “the idea that species live in integrated communities is a myth.”2 Ecologist William Drury, in his studies of forests, found no support for emergent properties, governing rules, or integration3. In his book, The Balance of Nature; Ecology’s Enduring Myth4, ecologist John Kricher states it bluntly, “there really is no such thing as a ‘balance of nature.’ Nor is there purpose to nature.” Evolutionarily speaking, Kricher points out, ecosystems do not evolve; they change because organisms change.
In addition to being false, the whole idea of the “balance of nature” is misleading. From it has come the view that ecosystems are a highly complex, integrated system of interactions between species, complexity that is beyond our understanding. The evidence, however, points to different conclusions. Drury reports “once seen, most of the interactions are simple and direct. Complexity seems to be a figment of our imaginations driven by taking the ‘holistic’ view.” Similarly, because ecology (at least until recently) has maintained that “natural communities tend towards equilibrium” Soulé concludes “the science of ecology has been hoist on its own petard.” In other words, ecologists have been misled by erroneously seeing what they assumed they would see.
Even as ecologists have, for the most part, abandoned the “balance of nature” thinking, it remains influential in popular thought and in agriculture. R. Ford Denison, in his book Darwinian Agriculture5, takes up this thread and asks the question, “Have ecosystem-level features, such as the mix of species and how they are distributed in space and time, been reliably improved by natural processes?” The answer is “no” according to Denison; natural communities have not been optimized and so we have no reason to mimic these communities in designing agricultural ecosystems. Because of this, Denison questions whether agroecologists, those for whom “the near-perfection of natural ecosystems is apparently the foundational hypothesis,” are misguided in promoting certain practices based on this thinking. The evidence, according to Denison, does not support them.
In Darwinian Agriculture, Denison concludes that because “evolution has improved trees much more consistently than it has improved forests,” we will find ‘nature’s wisdom’ not in natural ecosystems, but in individual species, where natural selection has improved survival and reproduction. And by looking at adaptations in individual plants and animals, “we may be able to improve on nature.”
I agree. If what we see in natural ecosystems is not optimized, but random (stochastic, say the ecologists), we should be able to do just as well or better. We can, with ingenuity, wisdom, and a good dose of humility, purposefully assemble systems that outperform natural ecosystems in providing both products and ecosystem services. By taking advantage of individual species’ properties and processes, and by managing abiotic conditions (soil physical and chemical properties and water levels, etc.) we can create designer agro-ecosystems, successful by criteria that matter in agriculture; productivity, efficiency, and stability. I propose that this is, in fact, what we have been doing all along (more on this my follow-up post), and that the “balance of nature” has only been a distraction from our efforts to improve the sustainability of our agriculture, a distraction that should be decisively cast aside.
1 Marris, E. (2013). Rambunctious Garden: Saving Nature in a Post-Wild World. Bloomsbury Publishing USA.
2 Soulé, Michael. (1995). “The Social Siege of Nature.” In Reinventing Nature? Responses to postmodern deconstruction. eds. M.E. Soule and G. Lease. Washington: Island Press.
3 Drury, W.H. (1998). Chance and Change: Ecology for Conservationists. Berkeley: University of California Press.
4 Kricher, J. (2009). The Balance of Nature: Ecology’s Enduring Myth. Princeton University Press.
5 Denison, R. F. (2012). Darwinian Agriculture: How Understanding Evolution Can Improve Agriculture. Princeton University Press. (Denison’s other main thesis in this book is that natural selection has left us few tradeoff-free opportunities for genetic improvement through genetic engineering. Full Disclosure – Denison served as my major professor in graduate school at UC-Davis.). His book blog.
Comments
Andy, surely ‘balance’ and ‘complexity’ are different things? The quotation from Drury begs some questions in this respect: ‘Once seen, most of the interactions are simple and direct’. So first we have to see them, which isn’t a trivial problem (Donald Rumsfeld’s ‘unknown unknowns’ spring to mind). And then they will surely appear simple and direct if we look at them one by one, as the quotation implies, but that’s not how they actually present themselves in natural or agro-ecosystems. The farmer has to optimise many and conflicting variables with partial knowledge, so while you’re surely right that nature can be ‘improved on’ from a human perspective (virtually the definitional conceit of any type of farming), I’m not yet persuaded that the notion of complexity should be abandoned – or to put it another way, maybe you’re not stressing the ‘humility’ you mention enough. As we’ve learned so often before, many ‘improvements’ have downstream costs that we tend to underestimate a priori. So on balance, I’m not sure that metaphors of balance and complexity are such bad guides for everyday farming practice.
Chris, yes, I agree that they are different things. In the context of my post, I think they are related to the whole “balance of nature” thinking in which it is the complexity of ecosystems that give them their balance.
However, since the balance idea does not seem to hold up to scrutiny, I think these ecologists are also questioning, specifically, that type of complexity which produces the balance. This does not mean we ignore biodiversity, but rather look at it in a different way, as Denison says in his book, “Diversity may be there for a reason…but that does not mean that diversity is there for a purpose.” Drury also says “most species (in what we often call a community) are superfluous to the operation of those sets of species between which we can clearly identify important interactions.” These superfluous species perhaps represent the complexity that does not exist in terms of providing a balance to nature.
As to your suggestion that balance and complexity may still be good metaphors for the farm, I would ask, why use a metaphor based on a myth? The diversity in nature, as perhaps a different kind of complexity, even those superfluous species, can certainly be of use to us in agriculture, and we may decide they have value just because we like them, but complexity in the sense of the cause of the “balance of nature” is not so useful.
Andrew: I think questioning the `balance of nature’ is probably not the best critique of agroecological thinking. They seem to most concentrate of species-diverse systems and even woody climax vegetation as a model for agriculture. The latter is a non-starter: most food comes from grasses and most grasses are wind-pollinated – not a good idea in forest. However, the species-diversity model is also suspect. Just what ecosystems did early farmers choose as models? At least for Old World cereals – rice, wheat, sorghum – wild relatives can be found in (relatively) pure stands (large seeds and high ability to compete) often in yearly disturbed conditions. No surprise that we now have ploughing each year and cereal monocultures. But tell that to an agroecologist and you get your head bitten off. I think Denison is on to something.
I liked Dave Wood’s “Nature’s Fields” paper, but the best photo I have of natural monoculture’s is wild rice here in Minnesota. I’m seminars, I ask “How does this low plant diversity benefit the ecosystem? Greater productivity? Greater stability? No reason to expect any of these, because nature doesn’t adjust species numbers for ecosystem benefit, the way evolution adjusts leaf number for individual benefit.”
I think we need greater crop diversity, but species mixtures may not be the best way to use it.
Ford: Thanks. People forget that under several types of conditions only one plant species is able to survive. Wild rice, Rhizophora mangroves, turtle grass, Alnus on scree slopes , timberline trees or whatever. They are specialists – best at the job, often where `ecosystem services’ are needed, mud, sand, cold, salinity and the rest. To think that all species are equally good and the more the better is a bit unreal. There has been a vast research effort in multi-species interactions and very little as to just how monodominant vegetation flourishes. Yet the latter is probably more important for agriculture.
Really interesting, thanks. Botkin is another notable critic of the “Balance of Nature” myth, see his 2012 book “The Moon in the Nautilus Shell”. He traces the origins to Judeo-Christian myths of the Great Chain of Being which he argues still hold a tight grip on the western mind, with a strong influence on environmentalism. He also discusses Odum and others, pointing out that the science of ecology emerged alongside computers, hence cybernetics played a big role in early ecological theory- ironically, “Nature”- which was romanticized as sacred in its supposed balance and harmony- was actually modeled as if a machine.
I am just a newbie in the field of sustainable agriculture, but the entire time I was reading this I was thinking “haven’t we been doing that all along?” And then in the last paragraph you state just that. Honestly, the whole thing reads like an ad for Monsanto. It is quite disheartening to me that with all of the problems that we have caused with our monocultures and synthetic chemicals, anyone could still say we just need to keep doing the same thing (trying to bend natural systems to our will) but with a different outcome.
Please give answer for those questions;
1. How does holistic approach of agroecology allow or the integration of ecological soundness, economic viability, and social equity
Everything we do is within the context of nature your a prior conclusion that learning from nature is schizophrenic right out of the gate ecology is not dependent on computers at all not even wrong all these people are experimenting ultimately whatever we do must maintain the planets life support system or else
Well written article and interesting perspective. There certainly is a point to accelerating the development of individual species to suit our needs.
However, there are many principles of functioning ecosystems we can look towards in an attempt to replicate. Intermediate disturbance for example. Most ecosystems, especially grasslands and savannas, greatly benefit from intermittent disturbance from fire and grazing animals. This helps clear old growth, sequester carbon, and encourage new plant growth.
Concepts such as holistic management and farms such as Polyface Farm, attempt to model a functioning ecosystem and substitute species that help meet our needs.
Sure there is random variation in nature but the underlying principles driving adaptation have allowed life to proliferate in the face of extreme stress.
Andy, excellent and well written. The article just showed up on linkdin and I was embarrassed, being from WA, that a gentleman from FL had to point it out to me.
You are an asset to agriculture. You have been at it a while. I can remember when you fought hard to get cover crops started and now they are mainstream. Well done my man!
Thank you. I am glad you found some value in this.