Past extinction events are key to understanding how modern life will respond to climate change. For ecologists who study communities of interacting or

The importance of soft-bodied organisms in ancient food webs « Earth & Environmental Science « Cambridge Core Blog

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2021-08-11 21:30:07

Past extinction events are key to understanding how modern life will respond to climate change. For ecologists who study communities of interacting organisms, the fossil record holds a wealth of information about how different species react to environmental perturbations, but with a major drawback — it only captures species with bones and shells.

In a recent paper, my colleagues and I identified how one key bias in the fossil record—the lack of preservation of soft-bodied organisms, such as worms—might impact how we understand ancient communities and their dynamics.

Our research builds on the burgeoning science of food webs, which are networks of different organisms represented as “nodes” connected by “edges” that represent consumer-resource interactions. Mathematical analyses of food webs have revealed various aspects of community dynamics, such as stability, and are also used to evaluate how ecological communities may respond to future perturbations, such as abrupt climate change. Studies like this are becoming increasingly important considering our rapidly changing climate. However, inferences from modern food webs are limited by the fact that existing ecosystems have not experienced the range or intensity of climatic and other perturbations forecast for the future (i.e., modern food webs cannot adequately serve as analogs for the future).

The limitations of modern food webs have led researchers to turn to the fossil record to enhance our understanding of community responses to the significant current and future perturbations. The fossil record documents many different disturbances across the history of animal life. For example, researchers analyzing food webs constructed from fossil data have assessed community responses to perturbations such as mass extinctions (e.g., Roopnarine and Angielczyk 2015), which can help scientists to understand how the ongoing “sixth extinction” will affect the trajectory of modern life. Unfortunately, fossil data is biased. Unlike modern data, fossilized records of ancient communities are subjected to information loss caused by geological processes that can destroy evidence of the existence of certain taxa. This will affect how researchers interpret biotic interactions and ecosystem properties recorded in ancient food webs. Such biases need to be accounted for to draw robust ecological inferences about the past and future.