How do ecological controversies typically end?

We talk a lot around here about ecological controversies–asking why some ecological ideas become controversial, and polling ecologists on what they think about currently-controversial ideas.

But how do ecological controversies end? I can think of several possibilities:

  • The controversy gets resolved in favor of one side or the other, at least in the eyes of most people. Example: the late-90s controversy over whether effects of biodiversity on ecosystem function in “random draws” experiments are driven by a “sampling effect”. Resolved by widespread adoption of the Loreau & Hector (2001) additive partition and related approaches. (well, resolved except maybe in the eyes of a few holdouts)
  • The controversy gets resolved because everyone agrees that both sides were partially right. That is, everyone agrees that the answer to the controversial question is “it depends”, or “one side is right X% of the time, the other side is right 100-X% of the time”, or “one side is right under conditions Y and Z, the other side is right under other conditions”. This is purportedly the way all ecological controversies get resolved, but based on our poll data it’s actually not easy to find examples of ecological controversies that get resolved in this way! Though I can think of a few. The controversy over whether local-regional richness relationships typically are linear or saturating, for instance.
  • The controversy gets resolved when both sides turn out to be totally wrong. I’m thinking for instance of 19th century debates about the age of the Earth. As far as I know (please correct me if I’m wrong!), everyone involved missed on the low side.
  • The controversy gets resolved by a Hegelian synthesis of both sides’ opposing views. That is, a synthesis that shows that both sides had a point, but they also shared some blind spots. Synthesizing the views of both sides not only resolves the controversy (or points the way to showing how it could be resolved), but also raises new questions that both sides had overlooked. That’s more or less how the density-dependence vs. density-independence debate in population ecology was resolved (Bjornstad & Grenfell 2001).
  • The controversy devolves into two opposing camps who keep repeating the same points, while everyone else stops caring about the issue. Based on our poll results, that’s more or less how the controversy over ratio-dependent functional responses looks to be resolving itself. And further back, I think the SLOSS debate might be another example? As a grad student back in the late 90s, I recall David Ehrenfeld telling a class that, as EiC of Conservation Biology, he’d decided to stop publishing SLOSS papers because nobody had anything new to say on the issue.
  • The controversy stops without being resolved because everybody, including the main participants, stops caring about the issue. Can’t think of any examples of this in ecology off the top of my head.
  • The controversy gets resolved because it’s shown to not actually be a controversy. Ziebarth et al. (2010) is a possible example, showing that a famous old controversy over population regulation should never have been a controversy at all. There was actually no conflict between the claims the claims of the opposing camps. The whole debate was premised on a misunderstanding of the implications of the relevant empirical evidence. An example from evolutionary biology is Robert Mark’s brilliant demonstration that the whole debate over “spandrels” was premised on misunderstandings of architecture on the part of all the main participants.
  • The controversy doesn’t get resolved and just runs forever. P-values, anyone?

It would be interesting (and hard) to compile data on the frequency with which ecological controversies get resolved in different ways, and try to explain why different controversies were resolved differently. It would also be interesting to know if ecological controversies tend to get resolved differently these days than they used to. For instance, do more empirical controversies get resolved in favor of “it depends” these days, thanks to the widespread adoption of meta-analysis?

12 thoughts on “How do ecological controversies typically end?

    • Good question! My answer is “yes, partially”, because the terms of the debate were partially determined by the metaphor. If you’re arguing whether evolution is full of “architectural by-products” (Gould & Lewontin) or “obligatory design opportunities (Dennett), well, the very terms of the debate are set by a bad architectural metaphor. Get rid of the metaphor, and you change what the debate is about. I say “partially” because there were, and are, other debates about “constraints” in evolution that weren’t framed in terms of the “spandrels” metaphor, and so weren’t resolved by the discarding of the “spandrels” metaphor.

      • behavioral and evolutionary ecology used ‘fitness max in the face of constraints and tradeoffs’ as its major form of argument long before Spandrels paper, which is why we found its popularity completely puzzling. Just check any works on optimal foraging, life history evolution, kin selection , etc, etc..
        BUT the Mark paper did not resolve anything, nor dent the continuing influence of the Spandrels paper: In web-of-Science mark has been cited ~15 times, Spandrels ~3760 times, and ~ 140 times / yr recently. The Zombie walks.

  1. On the SLOSS debate, I would argue that it was a classic “fizzle out and ignore” scenario that ecology is so good at for a few decades. But I think there has been a resolution more recently. A number of studies have shown empirically that the answer to SLOSS is they are equal (e.g. papers by Yaron Ziv and students plus some others). This exactly matches the Fahrig answer that area per se is much more important than the fragmentation structure. So the answer to SLOSS is that it was a useless question – fragment structure doesn’t matter much.

    On the other hand you don’t address neutral theory. That debate was another classic “fizzle out and ignore”. We came up with the idea that communities are on a spectrum from mostly neutral to mostly niche. That let everybody win. But then we walked away and never answered the question about relative frequency (I think the evidence largely points to mostly niche). I would predict that we will return to this question in 20-25 years and show that it is mostly niche.

    • Ah, good, I was hoping that someone who actually knows something would chime in on the SLOSS thing. That’s way more efficient for me than actually having to, you know, look stuff up. 🙂

      And good point re: the connection to Lenore Fahrig’s recent work, I hadn’t thought of that.

      I wish I could say that I intentionally omitted the neutral theory example from the post just so you could have the pleasure of addressing it in the comments. 🙂 But the truth is I was writing fast and just using whichever examples happened to pop into my head first.

      I will be curious to see if your bold prediction holds! I predict that somebody will return to this question in 20-25 years, only to run into the same outcome: you can’t use species-abundance distributions or other “bulk” data on community structure to infer anything about how strong or weak stabilizing mechanisms are. It’ll be like the “null model wars” of the late ’70s and early ’80s getting revived with better permutation algorithms in the mid-90s. Everyone will eventually realize that, oh wait, the whole problem with this line of research was not lack of statistical rigor, so making our stats more rigorous doesn’t actually help. Then the same thing will happen again in another 20-25 years.

      • I agree that patterns testing neutral theory is not going to pan out. But we’ve already got stronger tests (e.g. predictions about spatial and temporal beta diversity which get pretty directly at the sampling/drift nature of neutral theory). Almost none of those tests have panned out.

    • The SLOSS debate, sensu stricto has, perhaps, fizzled out. However, I believe its essence has been given a new life in the form of the land-sparing vs land-sharing controversy. Although more nuanced than SLOSS, land-sparing basically says that having one large conserved “patch” is the most effective way to meet conservation goals while land-sharing suggests that it is better to have many smaller “patches” that are mixed in with other land-uses.

      I think it’s quite common for a controversy to be resolved but then reborn when the main parameters are described in more detail or slightly differently. Land-sparing/sharing explicitly defines the matrix as habitat with some conservation value. It adds a new spin to SLOSS that had previously considered the matrix as “hostile.” The debate is also different because a strict concept of “conservation value” has been expanded to consider trade-offs between biodiversity conservation and food production.

    • A correspondent has pointed out to me that saying SLOSS was a useless question is harsh and not accurate. I can’t get mad that nobody bothered to study the question for 20 years and then say that when they did get the answer it was useless. “surprising” or “redirecting us to other questions” would be more accurate than what I said. I actually find it pretty profound that the world is balanced on the knife’s edge where SL=SS. Additionally SLOSS did inspire lots of other good work.

  2. So, Gleason vs Clements. Gleason wins most of the time but Clements partly right? Then Clementsian dysclimax becomes an alternate state which generates the “do they exist” controversy which is resolved by fixing semantics (?) where everyone was more or less right, depending on the conditions they stated… (and how long a run of a sentence can be used to described the issue).

    Has “Exotic = Bad : Native = Good” been resolved yet (aside from in my mind)?

    • “Has “Exotic = Bad : Native = Good” been resolved yet (aside from in my mind)?”

      Not as far as I know, but I’m really the wrong person to ask. My impression is that one’s going to run forever.

    • Wow, I can’t even edit a run on sentence to say “run on sentence.” Must be early tryptophan overdose.

      I’m not sure about funding vs ethics. There are good examples of when an exotic species is a good choice, particularly for degraded areas where native pioneers don’t establish well. There are lots of examples of bad exotics of course. Seems to me that much of native = bad is dogma and for some is the mantra regardless of the situation.

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