Does rewilding improve ecosystem resilience?: a soundscape perspective

Understanding why some ecosystems appear more resilient to perturbation than others is of fundamental importance if we wish to avoid biodiversity collapse and maintain a habitable planet. There is a rapidly growing shift towards low intensity, large scale, semi-passive restoration approaches, such as rewilding, that seek to restore ecological processes

rather than deliver pre-defined structure-based outcomes. Within the overall context of rewilding harnessing the restorative power of beavers through their habitat engineering activities is becoming increasingly commonplace in Britain, with most English counties now having enclosed beaver projects either planned or in operation, a situation

unimaginable a decade ago. In Scotland Eurasian beavers have occurred again in the wild for about 20-years with their population now approaching 2000 animals and with plans to translocate them more widely. The ecological benefits that stem from dam building and the other engineering activities of beavers are, in some senses, well

established, with a catalogue of studies demonstrating increases in birds, plants, amphibians, invertebrates and bats [1]. These complement the ability of beaver ponds to intercept pollutants and improve downstream water quality, attenuate flow peaks and mitigate the disturbance effects of drought and wildfires [2]. However, the picture is

incomplete since many indicator biological taxa are studied in isolation while the benefits of beavers most likely do not accrue evenly and are sensitive to the surrounding landscape matrix. The degree of subsidy from aquatic to terrestrial systems and how this varies in relation to beaver activity, also remains poorly understood, despite its potential

importance to higher trophic levels when other resources are depleted [3]. Finally, although beaver ponds seem to provide a stabilising influence in the face of extreme events, it is unknown whether there is an accompanying ecological benefit in terms of enhanced resilience of populations, communities or ecosystem functions. The solution to

some of these questions has remained elusive in part because traditional monitoring approaches are invasive and costly and therefore cannot be deployed at the spatial and temporal frequency that is desirable.