Throughfall enrichment and stream nutrient chemistry in small headwater catchments with different land cover in southern Chile

Abstract

Land cover changes have a great impact on nitrogen (N) and phosphorous (P) fluxes catchments. In this study, we wanted to compare different land covers: deciduous (D), evergreen (E) (both native forests), and exotic Eucalyptus globulus plantation (EP), affected precipitation, and stream discharge on N and P species concentrations and fluxes, under a low deposition climate in south‐central Chile. For this, we collected bulk precipitation, throughfall, and stream water samples after 41 rainfall events in E and EP, during the period June 2009–March 2011, and 31 rainfall events in D, during the period October 2009–March 2011. The highest canopy enrichment of N and P species for throughfall was observed in deciduous forest, while E. globulus showed the minimum enrichment. Total nitrogen (total‐N) discharge in EP was about 8.6 times higher than that of E and D catchments. Total‐N annual retention was positive only in E and D catchments. However, EP catchment showed a net loss (−4.79 kg N ha/year). The biggest difference was observed in nitrate stream concentrations, which showed low values for E (3.4 ± 1.3 μg/L), while EP and D showed higher nitrate concentrations (84.9 ± 16.7 and 134.7 ± 36.7 μg/L, for EP and D, respectively). Total phosphorous (total‐P) discharge flux was low in EP (0.4 kg P ha/year), and negligible in E and D forests (<0.1 kg P ha/year). Total‐P annual retention was near to 1.0 kg N ha/year (on E and D), while a net loss (−1.5 kg N ha/year) was observed for EP. We attribute the observed differences in nutrient throughfall enrichment due to high multi‐stratified canopies in the native forests. Both deciduous and evergreen native forest‐covered catchments showed the highest retention of total‐N and total‐P, in contrast to Eucalyptus‐covered plantation

High‐frequency monitoring of hydrological and biogeochemical fluxes in forested catchments of southern Chile

“…Although we did not detect significant differences in nutrient concentrations among streams from different successional forest (Figures 3(c,d) and S2), there was a remarkable nutrient enrichment overall, via throughfall water (Table 2), which is highly relevant for ecosystem biogeochemistry (Hervé‐Fernandez et al, 2016; Nelson et al, 2013; Weathers et al, 2001, 2006). Because this study comprised a limited number of rain events at a specific time of the year, results are subject to uncertainties that must be addressed in future long‐term studies (Zhang & Wei, 2021).…”

Preface for the South American Hydrology Virtual Special Issue

“…Ochoa‐Tocachi et al () implemented a paired catchment setup and used data from 25 headwater catchments in the tropical Andes to link their hydrological responses to different types of human interventions (i.e., cultivation, afforestation, and grazing) and found that all anthropogenic interventions increased streamflow variability and generated significant reductions in catchment regulation capacity and water yield. Hervé‐Fernandez, Oyarzún and Woelfl () assessed the “two water worlds” theory through a whole year in two catchments, one covered by Eucalyptus nitens and the other by a native evergreen forest, finding that the two water worlds does not apply throughout the year confirming previous hypotheses. In addition their results suggest that E .…”

“…Eight of the manuscripts tackle the effects of afforestation of grasslands and native forest substitutions and forest management in catchments covered with fast growing forest plantations; two of them approach rainfall partitioning analyses (Silva et al, ; Soto‐Schönherr & Iroumé, ), one analysed throughfall enrichment and stream nutrient chemistry in small headwater catchments (Hervé‐Fernández, Oyarzún, Brumbt, et al, ), two studied the hydrological effects of forest plantation management (Almeida, Smethurst, Siggins, Cavalcante, & Borges, ; Silveira et al, ) and other types of human interventions (Ochoa‐Tocachi et al, ), and one investigated water sources for native and exotic tree species (Hervé‐Fernandez, Oyarzún, & Woelfl, ). Silva et al () studied throughfall patterns in sugarcane and riparian forest to understand the effect of sugarcane age and land use conversion, finding no significant differences between cycles of sugarcane, growth phases, and riparian forest.…”

“…other types of human interventions(Ochoa-Tocachi et al, 2016), and one investigated water sources for native and exotic tree species(Hervé-Fernandez, Oyarzún, & Woelfl, 2016) Silva et al (2016). studied throughfall patterns in sugarcane and riparian forest to understand the effect of sugarcane age and land use conversion, finding no significant differences between cycles of sugarcane, growth phases, and riparian forest.…”

Direct and indirect effects of rainfall and vegetation coverage on runoff, soil loss, and nutrient loss in a semi‐humid climate

“…At the same time, the increased root system improves the physical and chemical properties of the surrounding soil (Gao et al, 2009). Vegetation type can affect soil nutrient loss in the basin (Hervé‐Fernandez et al, 2016). Turnbull et al (2011) studied the loss and redistribution of soil N and P caused by runoff in the process of grassland degradation to shrub land and found that in areas dominated by shrubs, N losses were considerably higher than in grass areas.…”