SLU news

New thesis: Resilience and stability of freshwater invertebrate communities across space and time

Published: 07 June 2021
Cover of thesis.

Understanding ecosystem response to environmental change is one of the biggest challenges in ecology. In a new thesis, Hannah Fried-Petersen has studied ecosystem change from the perspectives of ecological and social-ecological resilience, ecosystem stability, and adaptive capacity.

The amount of disturbance that a particular ecosystem can handle while still maintaining its basic identity is referred to as ‘ecological resilience’. Assessing ecological resilience is key for management of biodiversity and ecosystem functioning. However, measuring ecological resilience is difficult because ecosystems are complex and since they may be affected by different disturbances at the same time. Furthermore, adaptive capacity and ecological stability, which form part of a system’s resilience, are also difficult to quantify. In her thesis, Hannah Fried-Petersen argues that stability and adaptive capacity form part of the ecological resilience of an ecosystem. They describe things about the ecosystem in its current state, like how resistant it is to change when disturbed, or the specific mechanisms that allow it to buffer a disturbance.

Hannah Fried-Petersen used freshwater invertebrate communities from Swedish lakes and streams as models of complex systems, to quantify indicators of stability and adaptive capacity of these communities. She found that there is variation in the stability of invertebrate community composition across time and space in Swedish lakes. This could be important for identifying particularly stable or unstable lakes and for understanding broad spatial patterns. She also found that functional redundancy and response diversity (metrics of adaptive capacity) show positive correlations at a broad spatial scale in Swedish streams. Both of these indicators were influenced by physiochemical characteristics of the waterbodies, as well as known pervasive anthropogenic disturbances in the landscape. This indicates that human activities are affecting stability and adaptive capacity in these systems.

The thesis highlights the importance of studying long-term and spatially extensive changes in biotic communities using a framework that integrates different aspects of ecosystem resilience to environmental change.

Dissertation and thesis

Hannah Fried-Petersen defends her thesis "Resilience and stability of freshwater invertebrate communities across space and time" on 8 June 2021. All interested are welcome to take part in the public defense online.

Read the thesis: Fried-Petersen, Hannah (2021). Resilience and stability of freshwater invertebrate communities across space and time. Diss. (sammanfattning/summary) Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880. ISBN 978-91-7760-754-0. eISBN 978-91-7760-755-7