The potential of peatlands in global climate change mitigation: a case study of Terceira and Flores Islands (Azores, Portugal) hydrologic services

Abstract

Given the high precipitation verified in the Azores, peatlands, as water retention structures, are promoters of landscape balance, reducing the frequency of major events such as landslides. However, these ecosystems face increased land-use change disturbances that are placing the future security of these critical ecosystem services in doubt. This study aims to estimate the current and potential hydrologic services, particularly, water storage and water efflux, provided by the peatlands of Flores and Terceira Islands. Peatlands were initially identified through the distribution of Sphagnum, obtained by a spectral signature from satellite image analysis (Sentinel 2, Rapideye), completed with photointerpretation and historical data. The results show actual distributions of natural peatlands of 2766 and 2414 ha, for Terceira and Flores, respectively, which are relatively lower than the potential area estimated as 8035 and 5231 ha, correspondingly (20 and 37% of the total island area). Nowadays, these peatlands can retain 412,280,135 m3 of water. The higher altitude and more pristine areas represent the largest hydrological reservoirs and natural sources of water services. Theoretically, if all peatlands were natural, this capacity would increase to 300% of the retained water. These differences are most strongly reflected in peatland areas that are currently degraded or replaced by anthropogenic vegetation. Natural peatlands also showed greater capacity to restraint gravitational water, working as accumulation structures. Enhancing the naturalness of these areas would increase these ecosystems’ ability to act better as a buffer in extreme climate events.Article HighlightsActual distribution of natural peatlands is 2766 and 2414 ha, for Terceira and Flores, quite lower than the potential area.Currently retain 412,280,135 m3 of water, but this value could increase to 300% with adequate management and restoration, considering peatlands' potential area. This study follows the goals of the United Nations Sustainable Development as well as the 2030 Agenda in terms of climate change mitigation.Enhancing the naturalness would increase these ecosystems’ ability to act better as a buffer in extreme climate events. Restoration of peatlands would increase natural responses to expected climate change, protecting landscape equilibrium and population safety.