Variability of snow water equivalent and snow energetics across a large catchment subject to Mountain Pine Beetle infestation and rapid salvage logging

Bewley, D.; Alila, Younes; Varhola, Andrés

doi:10.1016/j.jhydrol.2010.05.031

Cited by 49 publications

(65 citation statements)

References 34 publications

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“…Thus, it is possible that extra water was available to increase streamflow after the bark beetle outbreak. This has been postulated and debated [Bewley et al, 2010;Biederman et al, 2014;Pugh and Gordon, 2013] and observed over decades following previous spruce beetle outbreaks in the Rocky Mountains [Bethlahmy, 1974;Bethlahmy, 1975;Love, 1955]. While we cannot conclude that streamflow increased at GLEES, the observed decrease in summer ET is at least consistent with this hypothesis and warrants further investigation.…”

Section: Changes In Canopy Conductance and Evapotranspirationsupporting

confidence: 50%

Ecosystem CO₂/H₂O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles

et al. 2014

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Disturbances are increasing globally due to anthropogenic changes in land use and climate. This study determines whether a disturbance that affects the physiology of individual trees can be used to predict the response of the ecosystem by weighing two competing hypothesis at annual time scales: (a) changes in ecosystem fluxes are proportional to observable patterns of mortality or (b) to explain ecosystem fluxes the physiology of dying trees must also be incorporated. We evaluate these hypotheses by analyzing 6 years of eddy covariance flux data collected throughout the progression of a spruce beetle (Dendroctonus rufipennis) epidemic in a Wyoming Engelmann spruce (Picea engelmannii)-subalpine fir (Abies lasiocarpa) forest and testing for changes in canopy conductance (g c ), evapotranspiration (ET), and net ecosystem exchange (NEE) of CO 2 . We predict from these hypotheses that (a) g c , ET, and NEE all diminish (decrease in absolute magnitude) as trees die or (b) that (1) g c and ET decline as trees are attacked (hydraulic failure from beetle-associated blue-stain fungi) and (2) NEE diminishes both as trees are attacked (restricted gas exchange) and when they die. Ecosystem fluxes declined as the outbreak progressed and the epidemic was best described as two phases: (I) hydraulic failure caused restricted g c , ET (28 ± 4% decline, Bayesian posterior mean ± standard deviation), and gas exchange (NEE diminished 13 ± 6%) and (II) trees died (NEE diminished 51 ± 3% with minimal further change in ET to 36 ± 4%). These results support hypothesis b and suggest that model predictions of ecosystem fluxes following massive disturbances must be modified to account for changes in tree physiological controls and not simply observed mortality.

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Section: Changes In Canopy Conductance and Evapotranspirationsupporting

confidence: 50%

Ecosystem CO₂/H₂O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles

et al. 2014

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“…These climate changes have been associated with increasing rates of forest disturbance due to wildfire (Fauria and Johnson, 2006), insect infestation (Aukema et al, 2008), and disease (Woods et al, 2005). The hydrological cycle in mountain environments can be substantially altered by forest disturbance, leading to increased snow accumulation and snowmelt rates (Pomeroy and Gray, 1995;Boon, 2009;Burles and Boon, 2011;Pomeroy et al, 2012), enhanced surface runoff and peak flow (Whitaker et al, 2002;Pomeroy et al, 2012), and changing groundwater regimes (Rex and Dubé, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…The forest canopy dampens turbulent energy fluxes when compared with open snowfields (Harding and Pomeroy, 1996;Reba et al, 2012). As a result, energy to melt sub-canopy snow is dominated by radiation fluxes, which in turn are altered by extinction of shortwave transmission through the canopy and enhancement of longwave emission from canopies and trunks Sicart et al, 2004;Essery et al, 2008;Boon, 2009;Pomeroy et al, 2009;Ellis et al, 2013;Varhola et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Multi-variable evaluation of hydrological model predictions for a headwater basin in the Canadian Rocky Mountains

Fang

Pomeroy

Ellis

et al. 2013

Hydrol. Earth Syst. Sci.

114

151

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Abstract.One of the purposes of the Cold Regions Hydrological Modelling platform (CRHM) is to diagnose inadequacies in the understanding of the hydrological cycle and its simulation. A physically based hydrological model including a full suite of snow and cold regions hydrology processes as well as warm season, hillslope and groundwater hydrology was developed in CRHM for application in the Marmot Creek Research Basin (∼ 9.4 km 2 ), located in the Front Ranges of the Canadian Rocky Mountains. Parameters were selected from digital elevation model, forest, soil, and geological maps, and from the results of many cold regions hydrology studies in the region and elsewhere. Non-calibrated simulations were conducted for six hydrological years during the period 2005-2011 and were compared with detailed field observations of several hydrological cycle components. The results showed good model performance for snow accumulation and snowmelt compared to the field observations for four seasons during the period 2007-2011, with a small bias and normalised root mean square difference (NRMSD) ranging from 40 to 42 % for the subalpine conifer forests and from 31 to 67 % for the alpine tundra and treeline larch forest environments. Overestimation or underestimation of the peak SWE ranged from 1.6 to 29 %. Simulations matched well with the observed unfrozen moisture fluctuation in the top soil layer at a lodgepole pine site during the period 2006-2011, with a NRMSD ranging from 17 to 39 %, but with consistent overestimation of 7 to 34 %. Evaluations of seasonal streamflow during the period 2006-2011 revealed that the model generally predicted well compared to observations at the basin scale, with a NRMSD of 60 % and small model bias (1 %), while at the sub-basin scale NRMSDs were larger, ranging from 72 to 76 %, though overestimation or underestimation for the cumulative seasonal discharge was within 29 %. Timing of discharge was better predicted at the Marmot Creek basin outlet, having a Nash-Sutcliffe efficiency (NSE) of 0.58 compared to the outlets of the sub-basins where NSE ranged from 0.2 to 0.28. The Pearson product-moment correlation coefficient of 0.15 and 0.17 for comparisons between the simulated groundwater storage and observed groundwater level fluctuation at two wells indicate weak but positive correlations. The model results are encouraging for uncalibrated prediction and indicate research priorities to improve simulations of snow accumulation at treeline, groundwater dynamics, and small-scale runoff generation processes in this environment. The study shows that improved hydrological cycle model prediction can be derived from improved hydrological understanding and therefore is a model that can be applied for prediction in ungauged basins.

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“…Other reported causes are secondary impacts occurring as a result of forest mortality that enhance processes such as radiation (Royer et al, 2011;Varhola et al, 2010), changes in albedo (Winkler et al, 2010), evapotranspiration (Zou et al, 2010;Kang et al, 2006), groundwater availability (Bearup et al, 2014, and soil moisture states (Dale et al, 2001). Snow has been reported to play an important role in changes in streamflow (Solander et al, 2017;Bennett et al, 2015) through increased snow accumulation and snowmelt (Bewley et al, 2010;Boon, 2007), snow cover duration (Boon, 2009), reduced interception, canopy sublimation, and evapotranspiration in disturbed forests (Livneh et al, 2015b). Temperature changes were noted to play a role in decreasing streamflow in one of eight catchments examined in Somor (2010).…”

Section: K E Bennett Et Al: Climate-driven Disturbances In the Sanmentioning

confidence: 99%

“…Snow also melts quicker in response to increased shortwave radiation and turbulent heat transfers linked to negative longwave radiative fluxes (Burles and Boon, 2011). The responses have also been linked to decreased albedo due to higher litter and/or darker soils associated with dying trees (Bewley et al, 2010;Winkler et al, 2010). Other effects of tree mortality on the water balance include changes to soil moisture states, changes in groundwater recharge , and potential feedbacks to the atmosphere (Bonan, 2008).…”

Section: K E Bennett Et Al: Climate-driven Disturbances In the Sanmentioning

confidence: 99%

Climate-driven disturbances in the San Juan River sub-basin of the Colorado River

Bennett

Bohn

Solander

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. Accelerated climate change and associated forest disturbances in the southwestern USA are anticipated to have substantial impacts on regional water resources. Few studies have quantified the impact of both climate change and land cover disturbances on water balances on the basin scale, and none on the regional scale. In this work, we evaluate the impacts of forest disturbances and climate change on a headwater basin to the Colorado River, the San Juan River watershed, using a robustly calibrated (Nash-Sutcliffe efficiency 0.76) hydrologic model run with updated formulations that improve estimates of evapotranspiration for semiarid regions. Our results show that future disturbances will have a substantial impact on streamflow with implications for water resource management. Our findings are in contradiction with conventional thinking that forest disturbances reduce evapotranspiration and increase streamflow. In this study, annual average regional streamflow under the coupled climate-disturbance scenarios is at least 6-11 % lower than those scenarios accounting for climate change alone; for forested zones of the San Juan River basin, streamflow is 15-21 % lower. The monthly signals of altered streamflow point to an emergent streamflow pattern related to changes in forests of the disturbed systems. Exacerbated reductions of mean and low flows under disturbance scenarios indicate a high risk of low water availability for forested headwater systems of the Colorado River basin. These findings also indicate that explicit representation of land cover disturbances is required in modeling efforts that consider the impact of climate change on water resources.

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Variability of snow water equivalent and snow energetics across a large catchment subject to Mountain Pine Beetle infestation and rapid salvage logging

Cited by 49 publications

References 34 publications

Ecosystem CO₂/H₂O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles

Ecosystem CO₂/H₂O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles

Multi-variable evaluation of hydrological model predictions for a headwater basin in the Canadian Rocky Mountains

Climate-driven disturbances in the San Juan River sub-basin of the Colorado River

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Variability of snow water equivalent and snow energetics across a large catchment subject to Mountain Pine Beetle infestation and rapid salvage logging

Cited by 49 publications

References 34 publications

Ecosystem CO2/H2O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles

Ecosystem CO2/H2O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles

Multi-variable evaluation of hydrological model predictions for a headwater basin in the Canadian Rocky Mountains

Climate-driven disturbances in the San Juan River sub-basin of the Colorado River

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Product

Resources

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Ecosystem CO₂/H₂O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles

Ecosystem CO₂/H₂O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles