Lake sediments as environmental archives of past ecological changes: Learning from the past for better management of freshwater ecosystems

Senast ändrad: 09 september 2022

Simon Belle.

Aquatic ecosystems face tremendous changes due to a multitude of stressors among which climate change and eutrophication are the most widespread drivers of biodiversity dynamics. Predicting how global change will affect biodiversity remains, however, an elusive challenge for scientists and ecosystem managers worldwide.

Understanding the underlying drivers of biodiversity in a changing world requires that we consider how ecosystems respond adaptively to global change over long time scales, but environmental monitoring records do not extend beyond the past few decades. Fortunately, paleolimnological approaches, using lake sediments as ecological archives, can supplement monitoring data in freshwater lakes. Reconstructing past temporal dynamics of aquatic communities will therefore be an important step in developing a hierarchical understanding of the influences of multiple stressors on lake ecosystems.

My research focuses on unravelling the response of aquatic invertebrate biodiversity to natural and anthropogenic variations in environmental and climatic conditions. Specifically, I study the taxonomy of subfossil chironomid remains to provide unique insights into past temporal dynamics of aquatic biodiversity. I am particularly interested in the interactions between chironomid species and their environment (using functional trait-based approach) and with co-occurring species (using combined use of stable isotope and sedimentary DNA).

In this lecture, I will present how lake sediments can be used to learn from the past for better management of freshwater ecosystems. The first part of my lecture will introduce the basic theoretical principles and methodological approaches in the use of lake sediments in aquatic paleoecology. The second part will address how aquatic paleoecology is used to expand the temporal scale over which ecologists pose and investigate questions. I will also provide a few key examples, and explain how my research fills knowledge gaps in the links between biodiversity dynamics, global change, and ecosystem management. Finally, in the last part of the lecture, I will explain how the topics mentioned above relate to the management and preservation of aquatic ecosystems and biodiversity. I will discuss potential and limitations of the use of sediment records in quantifying the effectiveness of different management strategies and political decisions, as well as defining realistic restoration targets. I will conclude by explaining my strategy for future research and education at SLU.