Carbon sequestration rates indicate ecosystem recovery following human disturbance in the equatorial Andes

PLoS One. 2020 Mar 30;15(3):e0230612. doi: 10.1371/journal.pone.0230612. eCollection 2020.

Abstract

Few studies exist that document how high-elevation Andean ecosystems recover naturally after the cessation of human activities and this can limit the implementation of cost-effective restoration actions. We assessed Andean forest (Polylepis stands) and páramo grassland recovery along an elevation gradient (3,600-4,350 m.a.s.l.) in the Yanacocha Reserve (Ecuador) where natural recovery has been allowed since 1995. Within the Yanacocha Reserve in 2012 and 2014 the aboveground biomass (AGB), aboveground necromass (AGN) and belowground biomass (BGB) carbon (C) stocks were measured and C sequestration rates calculated as proxy of ecosystem recovery. The soil organic carbon (SOC) stock to 36-cm depth was also quantified during the 2012 survey. To explore potential drivers of spatiotemporal variation of the forest and páramo C stocks they were related to abiotic and biotic variables. Andean forest C stocks were influenced mainly by disturbance history and tree-species composition. Páramo C stocks´ spatial variation were related to the elevation gradient; we found a positive significant trend in páramo AGB-C stocks with elevation, whereas we found a significant negative trend in AGN-C stocks. Likewise, significant temporal changes were found for AGB-C and AGN-C stocks. Net increases in AGB-C stocks were the largest in the Andean forest and páramo, 2.5 Mg C ha-1 year-1 and 1.5 Mg C ha-1 year-1 respectively. Carbon sequestration rates were partly explained by environmental variables. In the Andean forest, plots with low dominance of Baccharis padifolia were observed to present higher AGB-C and lower BGB-C sequestration rates. In the páramo, higher sequestration rates for AGB-C were found at higher elevations and associated with higher levels of growth-forms diversity. Temporal changes in BGB-C stocks on the contrary were non-significant. Our results indicated that terrestrial aboveground C sequestration rates might be an appropriate indicator for assessing Andean forest and páramo recovery after human disturbance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomass
  • Carbon / analysis
  • Carbon Sequestration*
  • Climate
  • Ecosystem*
  • Ecuador
  • Humans
  • Soil / chemistry

Substances

  • Soil
  • Carbon

Grants and funding

This paper has been developed thanks to the financial support of: The EcoAndes Project conducted by CONDESAN and UN-Environment, funded by the Global Environmental Fund (GEF <http://www.thegef.org>). Grant number: 4750 The Swiss Agency for Development and Cooperation (SDC, < www.eda.admin.ch/sdc >) through the CIMA (Gran number PA0042-C011-0031) and Andean Forest Programs (Grant number 81028631). FC, MCL, EP The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.