The Anthropocene is a fantastic time to be a Quaternarist. The last 2.5 million years of global changes offer so many important natural experiments to understand the future, from abrupt climate change to extinction to species introductions to disturbance shifts. New advances are pushing the boundaries of what we can glean from the ecological flotsam and jetsam of the fossil record, and how we date it. The age of Big Data in ecology (e.g., NEON Inc.) and earth science (e.g., EarthCube) is providing an unprecedented ability to answer questions about change through space and through time. We have an embarrassment of riches, and an unprecedented demand for those intellectual treasures from our colleagues in other fields.
For a very long time, our field was largely qualitative and descriptive (in some ways, it still is). New field, laboratory, and analytic methods, give us the opportunity to connect pattern and process in ways we’ve never been able to before. These connections can be made through modeling and bringing together multiple streams of information. Exciting work by folks like Elisabeth Jeffers of the Long Term Ecology & Resource Stewardship Lab at Oxford University (e.g., Jeffers et al., 2011) is allowing us to explicitly test mechanisms that underlie the patterns we observe in paleorecords. Multi-proxy, interdisciplinary studies, like those that involve cross-collaborations with phylogeographers, ecosystem ecologists, or anthropologists, are bringing exciting new dimensions to understanding paleoecologies and paleoclimates.
One major untapped resource, however, is the present. You’re probably thinking, “Wait, I’m a paleo-scientist. I don’t study the present for a reason!” The Quaternary encompasses the last 2.588 million years until the present. That means I just typed the word “present” during the Quaternary. I’m eating Quaternary pretzels on a bus traveling on a highway through Quaternary Maine as I write this post. The Holocene is a convenient (if somewhat anthropocentric) stratigraphic unit—it’s just the most recent of many interglacials. It’s easy to conceive of paleoscience as prehistoric only – encompassing nothing after the written record. But for many of us, history is an important source of information. Weather logs from ships and early American forts, to paintings, to the sediment record of the late Cenozoic overburden (as my geologist friend likes to call the soil and sediment overlying her own records). I’m not talking about historical ecology or climate here. I’m talking about the temporal purview of our neo-ontological colleagues: now.
From proof-of-concept studies to modern experimental manipulations, there are many opportunities to understand the “known unknowns” of our science (sensu Jackson, 2012). Linking observation (e.g., the abundance of a pollen type) with an inference (e.g., the relative abundance of a tree species) has relied not only on the sediment-water interface, but modern experiments to understand the production, transport, fall speeds, depositions, and preservation of pollen (though much of that work was done decades ago and would be great to revive). I’m a big fan of this kind of work, both only in terms of proxy validation, like my work with the dung fungus Sporormiella (Gill et al., 2013), but also to explicitly understand the mechanisms behind the clues we see in the paleorecord.
So, what does this mean, exactly? My neo-ecological colleagues at the University of Maine and I are tackling a once-and-future problem from a joint paleo/neo ecological perspective: the loss of eastern hemlock (Tsuga canadensis). Based on our mutual interest on the connections between terrestrial and aquatic systems, my neontological colleagues and I decided to link our temporal perspectives and methodological expertise. We’ve got a pilot project going, where we created a series of mini-lakes to understand the impacts of hemlock loss on food webs and ecosystem processes. Our goal is to eventually link up our artificial, experimental system with the actual sediment record of the mid-Holocene hemlock decline.
Linking past and present perspectives will, we hope, allow us to understand our system in ways that would never be possible if we worked alone. I’m obviously excited about our own project, but I’d love to see this approach expanded to other systems and problems. There are so many situations where bridging the deep-time (and often broadly-spaced) perspectives of the Quaternary with the short-term, locally focused present. Being able to see your study system in action is, I’m finding, remarkably powerful. Being able to manipulate it is even better. Whether we use the past to inform modern experiments, or use the present to tease apart the mechanisms we see in the past, we can go so far beyond proxy validation (though that’s important, too). We’re all just doing science in the Quaternary, anyway.
Gill JL, et al. (2013). Linking abundances of the dung fungus Sporormiella to the density of bison: implications for assessing grazing by megaherbivores in palaeorecords. Journal of Ecology, 101, 1125-1136.
Jackson ST. (2012). Representation of flora and vegetation in Quaternary fossil assemblages: known and unknown knowns and unknowns. Quaternary Science Reviews, 49, 1-15.
Jeffers ES, Bonsall MB, Watson JE, & Willis KJ. (2012). Climate change impacts on ecosystem functioning: evidence from an Empetrum heathland. New Phytologist, 193, 150-164.