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.
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.