Methods in Temporal Ecology

Post provided by Althea L. Davies & M. Jane Bunting

This post presents our reflections from two sessions at the first British Ecological Society Annual Meeting since the Palaeoecology Special Interest Group (SIG) was formed. Did the term “palaeoecology” make you want to stop reading? Then you’re not alone – our field of ecology seems to have drifted apart from neoecology over the last couple decades. We seem to have been separated by our choice of methods, rather than brought together by the fascinating, complex and essential challenges of better understanding ecosystem function that we share.

The diversity of talks at BES 2018 showed that ecologists working on time scales beyond the scope of direct study are researching the same urgent, exciting questions as other flavours of ecology. And that they are doing it by using an ever-growing range of methods and technologies. The Thematic Session ‘Advancing Our Understanding of Long-Term Ecology’ showcased advances in studies of long-term ecology. The Palaeoecology Oral Session demonstrated the diversity within this field. We don’t have room to mention all presenters, so we’d like to highlight contributions from two speakers in each session which demonstrate how strong the shared ground between palaeoecology and neoecology is.

Advancing Our Understanding of Long-Term Ecology

Maria Dornelas, the opening speaker in the Thematic session, explored trends and rates of biodiversity change over multiple decades. She looked for early warning signs of an impending Mass Extinction event. Her analyses are based a database that pulls together records of species assemblages spanning 1874-2016.

In contrast, Jack Williams looked to the future in his keynote, discussing the extent to which climates (and communities) in coming decades will increasingly be novel. This will lead to a decrease in the predictive capacity of ecological models. He concluded that, in the face of current rapid changes, all ecologists should think of ourselves as temporal ecologists. We can’t continue to consider palaeoecologists’ emphasis on dynamic ecosystems as substantially different from other kinds of ecology.

The Palaeoecology Oral Session

Multiple speakers in both sessions showed how a wide range of methods, from species distribution models, organic chemistry and historical sources to the more familiar sedimentary archive records, can be used as a ‘time-machine’. These methods can help us to study how species respond and reassemble under conditions beyond current ecological experience. They also allow us to test and improve ecological forecasting.

A striking example in the Palaeoecology session was presented by Emily Mitchell. Emily’s research involves not just finding new species, but also exploring extinct ecosystems. Her work on the first marine animals uses “snapshot” fossil assemblages which were both killed and preserved by the deposition of volcanic ash during the Ediacaran, around 635-540 million years ago. She elegantly showed how modern models can be applied to understand what controls the distribution of sessile organisms in a completely unfamiliar ecosystem.

©Lubasi

The importance of longer-lived ecosystem components such as trees means that our understanding of some situations can be radically changed by considering different time scales. Repeat surveys of forest plots form the basis of our understanding of the responses of the Amazon rainforests to recent changes. But comparing the spatial distribution of pre- and post-colonial human activity in Amazonia with the distribution of forest plots led Crystal McMichael to raise a warning flag for users of that data. A disproportionate number of the plots may still be in a state of successional recovery from past human-mediated disturbance, rather than mature forest communities, in comparison to the Amazon ecoregion as a whole. As a result, community characteristics and ecosystem functioning deduced from the forest plot data may not be representative of mature tropical forest systems. So it may be a poor basis for evaluating climatic and conservation impacts.

What is Palaeoecology?

Jack Williams began his talk by offering a simple definition of palaeoecology as the use of geology-derived methods to study ecological problems. But the range of topics in his own talk and in the rest of these sessions showed that those were far from the only methods being used by researchers interested in temporal ecology (ecological system dynamics occurring beyond the direct observational range of the present-day researcher).

The new Palaeoecology SIG aims to strengthen understanding of the common concerns shared by palaeoecology with other types of ecologist. We want to provide a forum for all temporal ecologists regardless of the methods used. Our group will be a focus for palaeoecologists in the UK and beyond to continue to understand and develop our own particular tool-kit and the insights it provides into the ecologies of other times and places.

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