Shallow Peatlands as Sentinels of Climate Change

The ecosystem services provided by northern peatlands has motivated the profusion of research into their carbon and water storage functions and the processes that maintain these functions. Yet typically this research has been conducted in deep, laterally extensive peatlands. These systems exhibit numerous regulatory mechanisms that enhance resilience to disturbances like wildfire and stressors like climate. In contrast, shallow peatlands have demonstrated greater vulnerability to external environmental pressures, exhibiting higher moss moisture stress, lower net carbon sequestration, and higher burn severity.

Given that climate change is anticipated to enhance drying in northern peatlands, and increase the frequency, severity, and areal extent of wildfire, we suggest that the contemporary biogeochemical and hydrological behaviour of shallow peatlands presages the future behaviour of deep peatlands. The limited capacity of autogenic feedback mechanisms operating in shallow peatlands to regulate their environment offers a valuable opportunity to study the boundaries of peatland resilience – an opportunity only available with ecosystems that are operating on the margins of survivability. We advocate for the study of shallow peatlands to understand: 1) their spatial distribution and hydroclimatic envelope; 2) the strength of their regulatory mechanisms; 3) tipping points that manifest in these regulatory mechanisms; and 4) identification of metrics that indicate when thresholds have been exceeded. This will not only further our process-based understanding of peatland regulatory feedbacks, but also aid in peatland restoration, and contribute to our conceptualization of peatland development.