Rewilding watersheds: using nature’s algorithms to fix our broken rivers

Natalie K. Rideout,Matilda Kattilakoski,Donald J. Baird,Katie M. McGee,Wendy A. Monk,Bernhard Wegscheider

doi:10.1071/mf20335

Abstract

Rewilding is an ecological restoration concept that promotes the natural recovery of ecosystems, through (initial) active or passive removal of human influence. To support the application of rewilding approaches in rivers and their watersheds, we propose a framework to assess ‘rewilding potential’ based on measurement of basic river ecosystem functions (e.g. restoring flood and nutrient pulses), including examples of specific indicators for these processes. This includes a discussion of the challenges in implementing rewilding projects, such as lack of spatio-temporal data coverage for certain ecosystem functions or tackling ongoing problems once active management is removed. We aim to stimulate new thinking on the restoration of wild rivers, and also provide an annotated bibliography of rewilding studies to support this.

Highlights

Rivers have played a critical role in human history, providing communication routes for trade and access to resources, as sources of food and fibre, and as a result, have become modified and degraded through over-use
We further propose to move beyond vague ‘goal-setting’, which ignores the restoration of high-level ecosystem processes, towards a science-based rewilding framework designed for rivers and their associated watersheds, including measurable and trackable restoration of basic ecological functions, providing metrics of rewilding success
We are not alone in suggesting that a new paradigm in river management is urgently needed to reverse multi-stressor driven freshwater ecosystem decline (e.g. the ‘curve-bending’ approach suggested by Tickner et al (2020))

Summary

Introduction

Rivers have played a critical role in human history, providing communication routes for trade and access to resources, as sources of food and fibre, and as a result, have become modified and degraded through over-use. Restoration of river habitats is a highly active discipline within river science, yet many restoration efforts have been performed by engineers, geomorphologists and community groups, focusing on restoration of physical habitat through flow management or placement of in-channel structures. These activities rarely consider or address the recovery of basic ecosystem functions, and can require constant injections of cash and resources for their maintenance (Palmer et al 2014). We argue that a new paradigm in river management is urgently required, to renew degraded rivers by first restoring ecosystem functions and reconnecting species to functioning habitats. We believe that a new conservation approach, namely rewilding, Journal compilation Ó CSIRO 2021 Open Access CC BY www.publish.csiro.au/journals/mfr

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