On Ecological Rants and Microcosms

Recently, over at the blog Ecological Rants the eminent ecologist Charles Krebs wrote a post about the ills of simplification in ecology. The post focuses specifically on how ecology has been ‘led astray’ by simplified models and lab studies. This has recently been picked up on Dynamic Ecology by Jeremy Fox who responded generally to the post but specifically to the affront to microcosms. I strongly recommend you check them out for yourself and not just rely on my version of events.

I went on record a long time ago (in blog years I think 2011 was a century ago) that I believe that we need a multitude of approaches, so I don’t plan on wading into the microcosm debate. That we’re still having this debate exhausts me. Instead, I want to focus on a different angle in Kreb’s post. Here’s the specific section:

“If we assume equilibrial dynamics in our communities and ecosystems, we fly in violation of almost all long term studies of populations, communities, and ecosystems. The problem lies in the space and time vision of our science. Our studies are too short to show even a good representation of dynamics over a 100 year time scale, and the problems of landscape ecology highlight that what we see in patch A may be greatly influenced by whether patches B and C are close by or not. We see this darkly in a few small studies but are compelled to believe that such landscape effects are unusual or atypical. This may in fact be the case, but we need much more work to see if it is rare or common. And the broader issue is what use do we as ecologists have for ecological predictions that cannot be tested without data for the next 100 years?”

I agree with a lot of this paragraph, though my perspective on it is different. I agree that our focus for much of the past 60 years in community ecology has been on equilibrial dynamics at a specific spatial scale with limited understanding on the impact context (i.e. what patches are near what other patches) can have on the local community. Does this make it difficult for us to predict what will happen in the dynamic world we actually live in? Yes. But unlike Krebs I don’t see the past few decades of research as a waste. We’ve learned a great deal about the fundamentals of ecological systems – species interactions, food web structure, biodiversity, niche partitioning, colonization, extinction, etc etc etc – all with the help of microcosms and simplified theory (and field studies and macroecology). We needed those decades of work to understand the basics of how communities are structured under idealized conditions.

SquidwardSquidward

 

Left: A child’s line drawing of SpongeBob’s Squidward. Right: Squidward.Does the drawing capture the essence of squidward? I’m biased, but I say yes. But how does a child get to being able to create a reasonable facsimile of something without first learning how pencils work, how they respond to hand movement, and how to simplify an image but still make it recognizable to others? I think this is also true with ecology. How do we know how to reasonably abstract a complicated system down to its most important components without first understanding what the components are and how to convey them in simple understandable ways?

Now, our challenge is to take what we have learned and apply it to the more complicated scenarios that are happening in nature (i.e. how does our Squidward change as he interacts with the dynamic setting of Bikini Bottom*). How do ecosystems change through time? What is the role of species interactions, context-dependence, and processes at different spatial and temporal scales in driving (or ameliorating) changes in food webs, niche partitioning, etc? These are pressing questions for our society as we try to predict how nature will respond to human perturbations, but these are also important for the basic development of our science. Some of this work will be done through detailed case studies out in the field, but some (hopefully) will be done with the help of theory, controlled experiments, and data-intensive approaches like macroecology to generate generalizations that help us know how to think and predict likely responses and scenarios.

The danger that I think Krebs is concerned about is that we become so attached to our clean, simplified view, our polished theories, that we refuse to engage with the more complicated scenarios. For example, if long-term studies suggest that the focus on equilibrial communities is misplaced, it would be to our detriment to continue to focus only on equilibrial communities in our theories and experiments. However, I don’t think this is happening (or if it was, I think momentum is shifting). Landscape ecology, metacommunity theory, biogeography, are all areas where people have been actively studying the very spatial issues Krebs bemoans us neglecting. I think he is more accurate about community ecology shying away from rigorously thinking about temporal dynamics, but I have a whole post on that planned, so I’ll spare you my rant. That we are starting to think about these more complex issues is what makes ecology exciting right now (and frustrating and really really hard). We have a grasp (tenuous, maybe, but a grasp nonetheless) on the fundamental, general concepts that bridge across ecosystems and organisms. We have more data, better tools, and better theoretical constructs than at any time in the past. Now is the time to tackle these more complex questions and to do so will require all the scientific approaches available to us – that includes field ecology, macroecology, theory, and, yes, microcosms.

 

*Yes I have been forced to watch too much SpongeBob lately.

8 Comments on “On Ecological Rants and Microcosms

  1. Excellent post, Morgan. There is so much red meat in your comments! I always feel the hair bristle on the back of my neck when folks say things like “too attached to this… completely ignoring that, etc.” Science moves in ebbs and flows, very naturally, and I see no reason for being critical of that tendency. So I agree with you that people often display a knack to criticize things simply because those things are at the forefront.

    ” Our studies are too short to show even a good representation of dynamics over a 100 year time scale, and the problems of landscape ecology highlight that what we see in patch A may be greatly influenced by whether patches B and C are close by or not.”

    To some extent I agree with this comment, but I also believe there looms two more significant and underlying issues. The first has to do generally with study design and more specifically with statistical power. So very often we assume our designs are sufficient, and our statistics are appropriate- and so very often we are mistaken. I might, for example, be inclined to believe 100 samples are sufficient for a given study. However, my hypotheses may not treat those 100 samples as a collective. Ecology is a tricky business, and I think by far and away the most difficult aspect of ecology is study design. Ergo, I would say the problems Krebs eludes to are not necessarily a product of limitations in spatio-temporal dynamics, but rather at least in part flawed designs and related statistics.

    We can, for instance, assess community dynamics over 100 year or even greater time scales with appropriate approaches. By way of a rudimentary example- watershed A was burned 100 yrs ago, B 50 yrs ago, C 25 yrs ago. As such, we can approach many community ecology questions assessing relatively long temporal scales in the present moment. Replication, of course, is always very difficult concerning field studies- and that is likely a barrier we never overcome. It’s just the nature of the beast.

    Secondly, the area where I see our greatest difficulty in advancing the science of ecology concerns uniformity of protocols. We still very much have a cottage industry mentality resulting in a wide array of approaches to similar topics. That makes it difficult, if not impossible, to merge data and derive quantitative assessments. That I believe is where the spatio-temporal aspect rears its ugly head. Lab A applies one set of spatio-temporal approaches, while labs B through Z each have their own sets. Complicating it further are the specifics of data acquisition.

    So in my warped world view, I argue that the absence of standardized protocols, along the lines of what we see in medicine, is far more a handicap that what Krebs highlights.

  2. Interesting points Morgan. Certainly, we don’t only focus on equilibrial dynamics, but it far and away dominates the literature I would argue. My perception of ESA this year was that it was even gaining steam whether those using equilibrial assumptions realized it or not. So, not totally buying that the momentum is shifting, but I would be ecstatic to be wrong : D

  3. @David: Thanks for stopping by and leaving your thoughts. I agree that part of the problem is standardization of data collection – which is what NEON is supposed to help with by providing standardized data collection for a variety of measures across multiple ecosystems.

    @Nate: Hey Nate! Great to hear from you. Well, I have to admit I believe the optimistic view with respect to spatial issues more than I do for the temporal ones (which is why I have a blog post on that rattling in my head). I agree, the equilibrial perspective is pervasive and we’ve been really reluctant as a field to grapple with time in a serious fashion. However, I do think the forces of change are beginning to gather and I point to this non-exhaustive list of recent developments: 1) Hasting’s recent MacArthur Award is large part about the importance of thinking about time and in particular thinking about non-equilibrial dynamics, 2) Chesson is now working on environmental non-stationarity in the context of coexistence (http://eco.confex.com/eco/2015/webprogram/Paper54006.html) , 3) the temporal dynamics of species richness debate (the fact that there even is one occurring is a big shift), 4) increasing paleoecology presence at ESA (which is much needed since I think most people have no frame of reference for how much ecosystems have changed even just since the last ice age), 5) a scattering of people at ESA this year trying to wrestle with the idea of time scales and applying tools like wavelets, etc (which is a scattering more than I’ve seen in the past).
    I agree that none of these herald that a new era has begun, but I think it is a sign that maybe we are finally getting a critical mass of people interested in temporal dynamics of communities that we can start making some progress.

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