Carbon sequestration and methane emissions along a microtopographic gradient in a tropical Andean peatland

Jorge A Villa; Gloria M Mejía; Daniela Velásquez; Andrés Botero; Sharon A Acosta; Juliana M Marulanda; Ana M Osorno; Gil Bohrer

doi:10.1016/j.scitotenv.2018.11.109

Carbon sequestration and methane emissions along a microtopographic gradient in a tropical Andean peatland

Sci Total Environ. 2019 Mar 1:654:651-661. doi: 10.1016/j.scitotenv.2018.11.109. Epub 2018 Nov 10.

Authors

Jorge A Villa¹, Gloria M Mejía², Daniela Velásquez², Andrés Botero², Sharon A Acosta², Juliana M Marulanda², Ana M Osorno², Gil Bohrer³

Affiliations

¹ Grupo de Investigación Aplicada al Medio Ambiente GAMA, Corporación Universitaria Lasallista, Carrera 51 no. 118 sur-57, Caldas, Antioquia 055440, Colombia; Department of Civil, Environmental & Geodetic Engineering, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210, USA. Electronic address: villa-betancur.1@osu.edu.
² Grupo de Investigación Aplicada al Medio Ambiente GAMA, Corporación Universitaria Lasallista, Carrera 51 no. 118 sur-57, Caldas, Antioquia 055440, Colombia.
³ Department of Civil, Environmental & Geodetic Engineering, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210, USA.

PMID: 30447603
DOI: 10.1016/j.scitotenv.2018.11.109

Abstract

Tropical alpine peatlands are among the least studied wetlands types on earth. Their important ecosystem services at local and regional scope are currently threatened by climate and land use changes. Recent studies in these ecosystems suggest their importance to the provision of climate regulation services, prompting a better understanding of the underlying functions and their variability at ecosystem scales. The objective of this study is to determine the variability of methane (CH₄) fluxes and carbon (C) sequestration within a tropical alpine peatland in three locations along a microtopographic gradient and its associated plant diversity. These locations accounted for: 1) hummocks, found mostly near the edge of the peat with a water table below the soil surface, 2) lawns, in the transition zone, with a water-table near the soil surface, and 3) hollows, permanently flooded with a water table above the soil surface, composed of small patches of open water intermingled with unconsolidated hummocks that surface the water level. Results indicate that CH₄ flux is lowest in the lawns, while C sequestration is highest. Conversely, the hummock and hollow have higher CH₄ flux and lower C sequestration. In addition, plant diversity in the lawns is higher than in the hummock and hollow location. Dryer conditions brought by current climate change in the northern Andes are expected to lower the water tables in the peatland. This change is expected to drive a change in CH₄ flux and C sequestration at the lawns, currently dominating the peatland, towards values more similar to those measured in the hummocks. This decrease may also represent a change towards the lower plant diversity that characterized the hummock. Such changes will reduce the ratio of C sequestration:CH₄ flux signifying the reduction of resilience and increment of vulnerability of the climate-regulating service to further perturbations.

Keywords: Carbon sequestration; Climate regulation; Ecosystem services; Methane emission; Páramo; Resilience; Vulnerability.