Comparison of carbon and water fluxes and the drivers of ecosystem water use efficiency in a temperate rainforest and a peatland in southern South America

• DOI: 10.5194/bg-21-1371-2024
• Publication Date: 2024-03-18T12:58:16Z
• Authors: Jorge F. Perez-Qu...; David Trejo; Javier Lopatin; David Aguilera; Bruce Osborne; Mauricio Gallegui...; Luca Zattera; Juan L. Celis-Diez; Juan J. Armesto
• Keywords: Ecosystem respiration; Water Use Efficiency; Temperate rainforest; Carbon sink

Abstract. The variability and drivers of carbon water fluxes their relationship to ecosystem use efficiency (WUE) in natural ecosystems southern South America are still poorly understood. For 8 years (2015–2022), we measured dioxide net exchange (NEE) evapotranspiration (ET) using eddy covariance towers a temperate rainforest peatland Chile. NEE was partitioned into gross primary productivity (GPP) respiration (Reco), while ET evaporation (E) transpiration (T) used estimate different expressions WUE. We then the correlation between detrended time series structural equation modelling identify main environmental WUE, GPP, ET, E T. results showed that forest consistent sink (−486 ± 23 g C m−2 yr−1), was, on average, small source (33 21 yr−1). WUE is low both likely explained by high annual precipitation this region (∼ 2100 mm). Only included atmospheric demand seasonal variation. Variations were related more changes than T remained relatively stable, accounting for around 47 % most study period. ecosystems, increased with higher global radiation surface conductance when table closer surface. Higher values also found wind speeds air temperatures peatland. absence close GPP dominance plant species either do not have stomata (i.e. mosses or epiphytes forest) poor stomatal control anisohydric tree forest). observed increase potential last 2 decades projected drought suggests could these particularly forest, where may be significant.