Land use change in the Ecuadorian páramo: The impact of expanding agriculture on soil carbon storage

ABSTRACT

The Andean páramo is notable for high soil carbon storage and its contribution to ecosystem services. However, the páramo’s ability to maintain high soil carbon levels is threatened by land use change from tussock grassland and shrublands to agricultural uses. A chronosequence study was conducted in the páramo around Quito, Ecuador, to determine the rate of soil carbon loss from traditional fallow agriculture. In parallel, a land use and land cover classification of Landsat images was used to measure the change in agricultural areas between 1991 and 2017. There was a significant negative relationship between the time since initial cultivation of a field and soil C: Older agricultural sites had significantly less C compared to natural ecosystems due to an average loss of 0.045 percent soil C per year. Undisturbed sites had significantly more soil C than cultivated sites but not pastures or fallow fields, indicating that cultivation is the most detrimental stage of the fallow agricultural cycle for soil C storage. There was an 838 percent increase in cultivated land between 1991 and 2017 but a 10 percent decrease in pastures, indicating a trend away from traditional regenerative agriculture toward land use types that lead to substantial losses in soil carbon.

KEYWORDS:

• Andes
• ecosystem services
• fallow agriculture
• Andosols

Acknowledgments

Publication made possible in part by support from the Berkeley Research Impact Initiative (BRII) sponsored by the UC Berkeley Library. We thank the Freshwater Ecology lab at USFQ for the field and laboratory space and equipment. We also thank Shahar Amitay and Valerie Dong for their help in the field and laboratory and Timothy Bowles for helpful comments. We also extend our gratitude to the U.S. Forest Service and Sustainable Wetlands Adaptation and Mitigation Program for use of the peatland data and maps. Finally, we are thankful for the anonymous reviewers for their comments on the article.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental material for this article can be accessed on the publisher’s website.

Additional information

Funding

This study was financially supported by the European Commission through the program Erasmus Mundus Master Course—International Master in Applied Ecology (EMMC‐IMAE; FPA2023‐0224/532524-1-FR-2012-1-ERA MUNDUS-EMMC). Support for ES and SC was provided by a Research Grant provided by Universidad San Francisco de Quito.