Early ecosystem responses to watershed restoration along a headwater stream

Emilie M.F. Kallenbach; Kaj Sand-Jensen; Jonas Morsing; Kenneth Thorø Martinsen; Theis Kragh; Karsten Raulund-Rasmussen; Lars Båstrup-Spohr

doi:10.1016/j.ecoleng.2018.03.005

Early ecosystem responses to watershed restoration along a headwater stream

Emilie M.F. Kallenbach^*, Kaj Sand-Jensen, Jonas Morsing, Kenneth Thorø Martinsen, Theis Kragh, Karsten Raulund-Rasmussen, Lars Båstrup-Spohr

^*Corresponding author af dette arbejde

2 Citationer (Scopus)

Abstract

Along many streams, natural riparian vegetation has been replaced by agricultural fields or plantations resulting in ecosystem alterations due to changes of the interactions across the land-water ecotone. We studied the effect of restoration interventions by removing a dense spruce plantation in a 25 m wide zone along a 4 km section of a headwater stream. Water discharge, nutrient and total organic carbon concentrations were unaffected by the intervention, which only involved 0.7% of the catchment area. Focusing on the oxygen dynamics within several sections of the stream revealed that the stream water was generally oxygen under-saturated both before and after the restoration reflecting the dominance of heterotrophy over photoautotrophy typical of small streams. Oxygen saturation was tightly coupled to water discharge, with anoxia or hypoxia developing during low summer flow, and levels just below saturation during high autumn-spring flow at low temperature and low metabolism. Stream-near felling increased incident irradiance and reduced the duration and extent of summer hypoxia despite unaltered discharge, temperature and concentration of total organic carbon. Increased incident irradiance was accompanied by higher oxygen saturation in open sections compared to control sections with intact tree cover. Diel oxygen changes followed incident irradiance during low summer flow, while alterations at high winter flow were caused by changes in temperature-dependent oxygen solubility and high reaeration. In conclusion, we show that anoxic or hypoxic oxygen levels occur in warm, low-flow summer periods and this stress is reduced when intense shading from spruce plantation is removed and in-stream oxygen production is stimulated.

Originalsprog	Engelsk
Tidsskrift	Ecological Engineering
Vol/bind	116
Sider (fra-til)	154-162
Antal sider	9
ISSN	0925-8574
DOI	https://doi.org/10.1016/j.ecoleng.2018.03.005
Status	Udgivet - 2018

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10.1016/j.ecoleng.2018.03.005

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title = "Early ecosystem responses to watershed restoration along a headwater stream",

abstract = "Along many streams, natural riparian vegetation has been replaced by agricultural fields or plantations resulting in ecosystem alterations due to changes of the interactions across the land-water ecotone. We studied the effect of restoration interventions by removing a dense spruce plantation in a 25 m wide zone along a 4 km section of a headwater stream. Water discharge, nutrient and total organic carbon concentrations were unaffected by the intervention, which only involved 0.7% of the catchment area. Focusing on the oxygen dynamics within several sections of the stream revealed that the stream water was generally oxygen under-saturated both before and after the restoration reflecting the dominance of heterotrophy over photoautotrophy typical of small streams. Oxygen saturation was tightly coupled to water discharge, with anoxia or hypoxia developing during low summer flow, and levels just below saturation during high autumn-spring flow at low temperature and low metabolism. Stream-near felling increased incident irradiance and reduced the duration and extent of summer hypoxia despite unaltered discharge, temperature and concentration of total organic carbon. Increased incident irradiance was accompanied by higher oxygen saturation in open sections compared to control sections with intact tree cover. Diel oxygen changes followed incident irradiance during low summer flow, while alterations at high winter flow were caused by changes in temperature-dependent oxygen solubility and high reaeration. In conclusion, we show that anoxic or hypoxic oxygen levels occur in warm, low-flow summer periods and this stress is reduced when intense shading from spruce plantation is removed and in-stream oxygen production is stimulated.",

keywords = "Ecological restoration, Forest clearance, Hypoxia, Oxygen conditions, Watershed restoration",

author = "Kallenbach, {Emilie M.F.} and Kaj Sand-Jensen and Jonas Morsing and Martinsen, {Kenneth Thor{\o}} and Theis Kragh and Karsten Raulund-Rasmussen and Lars B{\aa}strup-Spohr",

year = "2018",

doi = "10.1016/j.ecoleng.2018.03.005",

language = "English",

volume = "116",

pages = "154--162",

journal = "Ecological Engineering",

issn = "0925-8574",

publisher = "Elsevier",

}

TY - JOUR

T1 - Early ecosystem responses to watershed restoration along a headwater stream

AU - Kallenbach, Emilie M.F.

AU - Sand-Jensen, Kaj

AU - Morsing, Jonas

AU - Martinsen, Kenneth Thorø

AU - Kragh, Theis

AU - Raulund-Rasmussen, Karsten

AU - Båstrup-Spohr, Lars

PY - 2018

Y1 - 2018

N2 - Along many streams, natural riparian vegetation has been replaced by agricultural fields or plantations resulting in ecosystem alterations due to changes of the interactions across the land-water ecotone. We studied the effect of restoration interventions by removing a dense spruce plantation in a 25 m wide zone along a 4 km section of a headwater stream. Water discharge, nutrient and total organic carbon concentrations were unaffected by the intervention, which only involved 0.7% of the catchment area. Focusing on the oxygen dynamics within several sections of the stream revealed that the stream water was generally oxygen under-saturated both before and after the restoration reflecting the dominance of heterotrophy over photoautotrophy typical of small streams. Oxygen saturation was tightly coupled to water discharge, with anoxia or hypoxia developing during low summer flow, and levels just below saturation during high autumn-spring flow at low temperature and low metabolism. Stream-near felling increased incident irradiance and reduced the duration and extent of summer hypoxia despite unaltered discharge, temperature and concentration of total organic carbon. Increased incident irradiance was accompanied by higher oxygen saturation in open sections compared to control sections with intact tree cover. Diel oxygen changes followed incident irradiance during low summer flow, while alterations at high winter flow were caused by changes in temperature-dependent oxygen solubility and high reaeration. In conclusion, we show that anoxic or hypoxic oxygen levels occur in warm, low-flow summer periods and this stress is reduced when intense shading from spruce plantation is removed and in-stream oxygen production is stimulated.

AB - Along many streams, natural riparian vegetation has been replaced by agricultural fields or plantations resulting in ecosystem alterations due to changes of the interactions across the land-water ecotone. We studied the effect of restoration interventions by removing a dense spruce plantation in a 25 m wide zone along a 4 km section of a headwater stream. Water discharge, nutrient and total organic carbon concentrations were unaffected by the intervention, which only involved 0.7% of the catchment area. Focusing on the oxygen dynamics within several sections of the stream revealed that the stream water was generally oxygen under-saturated both before and after the restoration reflecting the dominance of heterotrophy over photoautotrophy typical of small streams. Oxygen saturation was tightly coupled to water discharge, with anoxia or hypoxia developing during low summer flow, and levels just below saturation during high autumn-spring flow at low temperature and low metabolism. Stream-near felling increased incident irradiance and reduced the duration and extent of summer hypoxia despite unaltered discharge, temperature and concentration of total organic carbon. Increased incident irradiance was accompanied by higher oxygen saturation in open sections compared to control sections with intact tree cover. Diel oxygen changes followed incident irradiance during low summer flow, while alterations at high winter flow were caused by changes in temperature-dependent oxygen solubility and high reaeration. In conclusion, we show that anoxic or hypoxic oxygen levels occur in warm, low-flow summer periods and this stress is reduced when intense shading from spruce plantation is removed and in-stream oxygen production is stimulated.

KW - Ecological restoration

KW - Forest clearance

KW - Hypoxia

KW - Oxygen conditions

KW - Watershed restoration

U2 - 10.1016/j.ecoleng.2018.03.005

DO - 10.1016/j.ecoleng.2018.03.005

M3 - Journal article

AN - SCOPUS:85043976367

SN - 0925-8574

VL - 116

SP - 154

EP - 162

JO - Ecological Engineering

JF - Ecological Engineering

ER -

Early ecosystem responses to watershed restoration along a headwater stream

Abstract

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