Crossing a critical threshold: Accelerated and widespread land use changes drive recent carbon and nitrogen dynamics in Vichuquén Lake (35°S) in central Chile

Fuentealba, Magdalena; Latorre, Claudio; Frugone-Álvarez, Matías; Sarricolea, Pablo; Godoy-Aguirre, Carolina; Armestó, Juan J.; Villacís, Leonardo A.; Carrevedo, María Laura; Meseguer-Ruiz, Óliver; Valero‐Garcés, Blas L.

doi:10.1016/j.scitotenv.2021.148209

Cited by 5 publications

(2 citation statements)

References 47 publications

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“…There is abundant evidence of increased soil erosion in Chilean tree plantations, such as truncated soil profiles in an eucalyptus stand at 36 o 37'S (Banfield et al, 2018), a fourfold increase in net soil loss under pine stands relative to native forest at Talcamavida (37 o 7'S) and Nacimiento (37 o 30'S) (Aburto et al, 2020) or changes in nutrient cycles and increased sedimentation rates in coastal lakes, such as Matanza (33 o 45'S, Fuentealba et al, 2020), Vichuquén (34 o S, Fuentealba et al, 2021), San Pedro (36 o 51', Cisternas et al, 2001), and Lanalhue (37 o S, Alaniz et al, 2021). Based on such strong empirical evidence along CCR and our own results (Fig.…”

Section: Discussionmentioning

confidence: 99%

Exotic tree plantations in the Chilean Coastal Range: Balancing effects of discrete disturbances, connectivity and a persistent drought on catchment erosion

Tolorza

Mohr

Zambrano‐Bigiarini

et al. 2023

Preprint

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The Coastal Range in the Mediterranean segment of the Chilean active margin is a soil mantled landscape able to store fresh water and potentially support a biodiverse native forest. In this landscape, human intervention has been increasing soil erosion for ~200 yr, with the last ~45 yr experiencing intensive management of exotic tree plantations. At the same time, this landscape has been affected by a prolonged megadrought, and how the anthropogenic disturbances and hydrometeorologic trends affect sediment transport is not yet well understood. In this study we calculate a decadal-scale catchment erosion rate from suspended sediment loads and compare it with a 10-year-scale catchment denudation rate estimated from detritic 10Be. We then contrast these rates against the effects of discrete disturbances and hydroclimatic trends. Erosion/denudation rates are similar on both time scales, i.e. 0.018 ± 0.005 mm/yr and 0.024 ± 0.004 mm/yr, respectively. Recent human-made disturbances include logging operations during each season and a dense network of forestry roads, which increase structural sediment connectivity. Other disturbances include the 2010 M 8.8 Maule earthquake, and two widespread wildfires in 2015 and 2017. A decrease in suspended sediment load is observed during the wet seasons for the period 1986-2018 coinciding with a decline in several hydroclimatic parameters. The low 10-year denudation rate agrees with a landscape dominated by slow soil creep. The low 10-year-scale erosion rate and the decrease in suspended sediments, however, conflicts with both the observed disturbances and increased structural (sediment) connectivity. These observations suggest that, either suspended sediment loads and, thus, catchment erosion, are underestimated, and/or that decennial sediment detachment and transport were smeared by decreasing rainfall and streamflow. Our findings indicate that human-made disturbances and hydrometeorologic trends may result in opposite, partially offsetting effects on recent sediment transport, but both contribute to the degradation of the landscape.

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Section: Discussionmentioning

confidence: 99%

Exotic tree plantations in the Chilean Coastal Range: Balancing effects of discrete disturbances, connectivity and a persistent drought on catchment erosion

Tolorza

Mohr

Zambrano‐Bigiarini

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Nevertheless, we can discuss if the observed land management is a suitable solution for soil erosion mitigation in the CCR. There is abundant evidence of increased soil erosion in Chilean tree plantations, such as truncated soil profiles in an eucalyptus stand at 36 o 37'S (Banfield et al, 2018), a fourfold increase in net soil loss under pine stands relative to native forest at Talcamavida (37 o 7'S) and Nacimiento (37 o 30'S) (Aburto et al, 2020) or changes in nutrient cycles and increased sedimentation rates in coastal lakes, such as Matanza (33 o 45'S, Fuentealba et al, 2020), Vichuquén (34 o S, Fuentealba et al, 2021), San Pedro (36 o 51', Cisternas et al, 2001), and Lanalhue (37 o S, Alaniz et al, 2021). Based on such strong empirical evidence along CCR and our own results (Fig.…”

Section: Discussionmentioning

confidence: 99%

Exotic tree plantations in the Chilean Coastal Range: Balancing effects of discrete disturbances, connectivity and a persistent drought on catchment erosion

Tolorza

Mohr

Zambrano‐Bigiarini

et al. 2022

Preprint

View full text Add to dashboard Cite

The Coastal Range in the Mediterranean segment of the Chilean active margin is a soil mantled landscape able to store fresh water and potentially support a biodiverse native forest. In this landscape, human intervention has been increasing soil erosion for 200 yr, with the last 45 yr experiencing intensive management of exotic tree plantations. Such intense forest management practices come along with rotational cycles as short as 9-25 yrs, the construction of dense forest road networks, and the fostering of wildfire susceptibility due to the high amounts of fuel provided by dense plantation stands. Here we first compare decadalscale catchment erosion rates from suspended sediment loads with a 10ˆ4-years-scale catchment erosion rate estimated from detrital 10 Be. We then explore these erosion rates against the effects of discrete disturbances and hydroclimatic trends. Erosion rates are similar on both time scales, i.e. 0.018 ±0.005 mm/yr and 0.024 ±0.004 mm/yr, respectively. Recent human-made disturbances include logging operations during each season and a dense network of forestry roads, which increase structural sediment connectivity. Other disturbances include the 2010 M w 8.8 Maule earthquake, and two widespread wildfires in 2015 and 2017. A decrease in suspended sediment load is observed during the wet seasons for the period 1986-2018 coinciding with a decline in several hydroclimatic parameters. The low 10ˆ4-years erosion rate agrees with a landscape dominated by slow soil creep. The low 10-years-scale erosion rate and the decrease in suspended sediments, however, conflicts with both the observed disturbances and increased structural (sediment) connectivity. These observations suggest that, either suspended sediment loads and, thus, catchment erosion, are underestimated, and/or that decennial sediment detachment and transport were smeared by decreasing rainfall and streamflow. Our findings indicate that human-made disturbances and hydrometeorologic trends may result in opposite, partially offsetting effects on recent sediment transport.

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Machine learning modeling of lake chlorophyll content in a data scarce region (Northern Patagonia, Chile): insights for environmental monitoring

Caputo,

Molina,

Ayllon

et al. 2024

Inland Waters

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Crossing a critical threshold: Accelerated and widespread land use changes drive recent carbon and nitrogen dynamics in Vichuquén Lake (35°S) in central Chile

Cited by 5 publications

References 47 publications

Exotic tree plantations in the Chilean Coastal Range: Balancing effects of discrete disturbances, connectivity and a persistent drought on catchment erosion

Exotic tree plantations in the Chilean Coastal Range: Balancing effects of discrete disturbances, connectivity and a persistent drought on catchment erosion

Exotic tree plantations in the Chilean Coastal Range: Balancing effects of discrete disturbances, connectivity and a persistent drought on catchment erosion

Machine learning modeling of lake chlorophyll content in a data scarce region (Northern Patagonia, Chile): insights for environmental monitoring

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