What Makes a Niche in Nature? And Where Does it End Up?

Or: How to Learn from your Undergraduate Students

by Aaron Jonas Stutz

Let’s start with learning from the learners. In all of my courses, I attempt to challenge my early undergraduate (Freshman and Sophomore) students to clarify and make connections among concepts that my scientific colleagues and I don’t entirely agree on. Or even pay attention to.

I look at it this way. As many of my faculty colleagues in diverse institutions would vouch for, it is basically impossible for any one of us scientists to steer general academic conversations–within any given discipline or specialization–toward concept-focused issues of what we don’t understand, have failed to define, or have thoroughly muddled. This is partly because, as Thomas Kuhn (1996 [1962]) famously discussed, scientific research communities tend toward what are tacitly accepted as normal paradigms. No matter how compelling a lone dissenter’s argument may be, it’s unlikely that a broader research community will immediately see a shared interest in un-learning, re-learning, and creatively reorganizing and redefining key concepts, observation and analysis methods, questions, and all of the jargon and time spent reading and debating that goes with it.

In any case, for several years now, I have confronted my students in an Emory University 200-level core course in the Neuroscience and Behavioral Biology major with a major problem in studying the evolutionary foundations of human behavior:

  • what is the human niche … and where is it?

As I have discussed elsewhere on this blog (The Human Niche–An Overview), biological anthropologists and human biologists are undoubtedly interested in the evolution of the human niche. And they express increasing interest in the concept of niche construction dynamics. But if you put most of us on the spot and asked us to summarize what the human niche is–let alone what a niche is, in general–you’d get a lot of embarrassed expressions. From a few of us, you’d get concise, confident answers … but these would be sure to differ in dramatic ways. You’d be left scratching your head, wondering where to begin.

That is, where to begin roughing out a preliminary definition of the human niche.

And where to begin getting biological anthropologists and human biologists–those scientists best suited to refine that definition–to agree on broader theoretical themes to shape research priorities. Themes as different as “the role of hominins in the evolution of Pleistocene carnivore guilds,” “the symbolic niche,” “how climate has constrained and shaped human evolution,” and “the origins of an anthropocene era.”

Fortunately, undergraduate students have not already spent years investing in becoming part of a normal paradigm of scientific inquiry, whereas this is a structurally built-in occupational hazard for university research-focused faculty. By asking beginning undergraduates to grapple with defining or comparing concepts about which professional scientists disagree–but which are undoubtedly relevant for explaining and predicting a particular range of complex natural phenomena–professors can collaboratively work with their students to figure out new ways of framing their questions … and of selecting their observation and analysis methods.

OK. Enough of the background. Many readers will correctly guess that I felt inspired–or, arguably, obligated–to write this blog post when confronted by an unusual, challenging insight from a student, as we began to read about and discuss the concept of ecological niche.

So, what happened? In my introductory Neuroscience and Behavioral Biology core course on the foundations of behavior, I had asked my students to cover some readings about what a niche is and how it evolves with populations and adaptations in ecosystems. An important critical review essay is R.H. Whittaker and colleagues’ 1973 publication “Niche, Habitat, and Ecotope.” Although very technical in places, such an advanced reading is good for two reasons. On the one hand, it challenges students to advance informal hypotheses about what they think the article is about, and then try to use detailed textual evidence from within the article–along with supplementary readings and in-class lecture and discussion–to revise or refine that understanding. On the other hand, it gives the students an opportunity to see that very smart, collaborative, and professionally successful scientists (one of the co-authors of this classic essay, Simon Levin, went on to receive a MacArthur grant [a.k.a. genius grant] and is probably the most cited ecologist in the scientific literature over the past 25 years [see Levin 1992]) do not easily see all of the answers. But they can give future students good materials for building new, potentially more scientifically productive paradigms. In short, students can first appreciate why important scientists are giants … but little enough giants that they can reasonably get up on the shoulders of. So, in discussing Whittaker et al. (1973) in class the other day, one of my students called me out on summarizing the scientific essay in a way that contradicted one of their main points.

I had suggested that Whittaker et al. (1973) had emphasized separating out aspects of physical habitat from food-web factors in shaping the diversity of niches in an ecosystem. Yet, as my student pointed out, Whittaker et al. (1973:326) clearly stated that the two main aspects to separate out are local, intracommunity factors (what they call niche) and broader intercommunity factors or structures (what they call habitat). And quite clearly, those local factors may have to do with very particular habitat details, and not just trophic or food-web factors. As I re-read Whittaker et al. (1973:334) now, it is clear that they were trying to clarify ecosystem complexity, distinguishing the local from the regional. They were trying to give a formal model framework to the concepts of realized (local) and fundamental niche for a given species’ population network’s role in a regional set of ecosystems, spread across a wider habitat. Of course, it gave me pause to realize that I had managed rather willfully–yet unwittingly–to misread Whittaker et al. (1973). I got the bit about their aim to clarify the notion that a biological species’ niche is complex and multidimensional. But–in alarming contrast to what I urge my students to do, which is to read carefully, in order to figure out the nuts and bolts of an author’s argument, not just the general topic of that argument–I assumed I already knew where they were going.

When all of this discussion transpired last week, this led me to tell the class that we’d return to the topic after the weekend. Because it led me to emphasize that this is an opportunity to learn from a situation where a beginner seemed to read things more accurately than me, the experienced scientist. Now, remember that biological anthropologists like me don’t have a widely agreed-on, ready definition of the human niche. Or, at least if some of us do, we’d mainly invite debate rather than consensus (which is cause for optimism, because the scientific instinct is to test the proposed definition’s applicability to diverse cases and contexts, but this is something we should have been debating and studying for a while already). Perhaps more important, we are not in sufficient dialogue with ecologists who have continued to investigate what shapes and sustains a species’ niche in an ecosystem. I realize that–in my reading and teaching–I had been overemphasizing the importance of foodweb connections over physical habitat connections in ecosystems in general. Human evolution has long been dominated by our non-equilibrium impacts on foodwebs in which we have become top predators, plant food consumers and–especially with the advent of domestication–dispersers, and densely networked parasite population reservoirs. Only later have we begun to have widespread impacts on landscape or habitat factors. From my paleoanthropological perspective, the foodweb dimensions and landscape dimensions seem clearly different. But this is not the case for most ecologists studying ecosystems marginal to more intense human activities: montane forests, rivers and lakes, and shallow estuaries, for example. In those cases, it’s mainly about the local abiotic and foodweb factors, with occasional or indirect regional impacts (Whittaker et al. 1973). But human population networks are especially good at influencing ecosystem energy, matter, and information flows at multiple scales–ones that we consider daily or local, as well as regional ones. And now, global ones.

Thanks to my students, I have gained a better understanding of the research history in a related field (I’m a biological anthropologist working at learning more in-depth knowledge about how ecosystems, niches, and adaptations evolve together in diverse contexts, including those in which humans have no direct local impact). The main question I’ll be asking my students is how the complex contemporary human niche or ecotope came to occupy multiple landscape and time scales, dominated by multiple high-impact foodweb connections? This raises an even more basic question: how local was the early hominin niche that became so evolutionary modified during our subsequent descent from ancient ape origins?

A multi-dimensional view of the contemporary hominin (that is, human) ecotope. In contrast to the local landscape constraints emphasized by Whittaker et al. (1973), this depiction emphasizes how the human niche is remarkably complex in terms of foodweb connections and impacts. AND it spans extensive time and geographic scales.
A multi-dimensional view of the contemporary hominin (that is, human) ecotope. In contrast to the local landscape constraints emphasized by Whittaker et al. (1973), this depiction emphasizes how the human niche is remarkably complex in terms of foodweb connections and impacts. AND it spans extensive time and geographic scales.


Kuhn, Thomas S.
1996  [1962] The Structure of Scientific Revolutions. University of Chicago Press.
Levin, Simon A.
1992  The Problem of Pattern and Scale in Ecology: The Robert H. MacArthur Award Lecture. Ecology 73(6): 1943–1967.
Whittaker, R. H., S. A. Levin, and R. B. Root
1973  Niche, Habitat, and Ecotope. The American Naturalist 107(955): 321–338.