scholarly journals NEP of a Swiss subalpine forest is significantly driven not only by current but also by previous year's weather

2014 ◽  
Vol 11 (6) ◽  
pp. 1627-1635 ◽  
Author(s):  
S. Zielis ◽  
S. Etzold ◽  
R. Zweifel ◽  
W. Eugster ◽  
M. Haeni ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Linear Models ◽  
Environmental Drivers ◽  
Subalpine Forest ◽  
Co2 Uptake ◽  
Spruce Forest ◽  
Subalpine Spruce Forest ◽  
Eddy Covariance Measurements ◽  
Explained Variance

Abstract. Understanding the response of forest net ecosystem productivity (NEP) to environmental drivers under climate change is highly relevant for predictions of annual forest carbon (C) flux budgets. Modeling annual forest NEP with soil–vegetation–atmosphere transfer models (SVATs), however, remains challenging due to unknown delayed responses to weather of the previous year. In this study, we addressed the influence of previous year's weather on the interannual variability of NEP for a subalpine spruce forest in Switzerland. Analysis of long-term (1997–2011) eddy covariance measurements showed that the Norway spruce forest Davos Seehornwald was a consistent sink for atmospheric CO2, sequestering 210 ± 88 g C m−2 yr−1 on average. Previous year's weather strongly affected interannual variability of NEP, increasing the explained variance in linear models to 53% compared to 20% without accounting for previous year's weather. Thus, our results highlight the need to consider previous year's weather in modeling annual C budgets of forests. Furthermore, soil temperature in the current year's spring played a major role controlling annual NEP, mainly by influencing gross primary productivity early in the year, with spring NEP accounting for 56% of annual NEP. Consequently, we expect an increase in net CO2 uptake with future climate warming, as long as no other resources become limiting.

scholarly journals Forest NEP is significantly driven by previous year's weather

2013 ◽  
Vol 10 (10) ◽  
pp. 15587-15611
Author(s):  
S. Zielis ◽  
S. Etzold ◽  
R. Zweifel ◽  
W. Eugster ◽  
M. Haeni ◽  
...  
Keyword(s):  
Linear Models ◽  
Environmental Drivers ◽  
Co2 Uptake ◽  
Spruce Forest ◽  
Annual Variability ◽  
Subalpine Spruce Forest ◽  
Eddy Covariance Measurements ◽  
Explained Variance ◽  
Norway Spruce Forest

Abstract. Understanding the response of forest net ecosystem productivity (NEP) to environmental drivers under climate change is highly relevant for predictions of annual forest carbon (C) flux budgets. Modeling annual forest NEP with soil–vegetation–atmosphere transfer models (SVATs), however, remains challenging due to unknown responses of forests to weather of the previous year. In this study, we addressed the influence of previous year's weather on the inter-annual variability of NEP for a subalpine spruce forest in Switzerland. Analysis of long-term (1997–2011) eddy covariance measurements showed that the Norway spruce forest Davos Seehornwald was a consistent sink for atmospheric CO2, sequestering 210 ± 88 g C m−2 per year on average. Previous year's weather strongly affected inter-annual variability of NEP, increasing the explained variance in linear models to 53% compared to 20% without previous year's weather. Thus, our results highlight the need to consider previous year's weather in modeling annual C budgets of forests. Furthermore, soil temperature in the current year's spring played a major role controlling annual NEP, mainly by influencing gross primary productivity early in the year, with spring NEP accounting for 56% of annual NEP. Consequently, we expect an increase in net CO2 uptake with future climate warming, as long as no other resources become limiting.

scholarly journals A long-term record of carbon exchange in a boreal black spruce forest: means, responses to interannual variability, and decadal trends

2007 ◽  
Vol 13 (3) ◽  
pp. 577-590 ◽  
Author(s):  
ALLISON L. DUNN ◽  
CAROL C. BARFORD ◽  
STEVEN C. WOFSY ◽  
MICHAEL L. GOULDEN ◽  
BRUCE C. DAUBE
Keyword(s):  
Interannual Variability ◽  
Black Spruce ◽  
Spruce Forest ◽  
Carbon Exchange

scholarly journals Rozpad drzewostanu i odnowienie świerka a struktura i dynamika karpackiego boru górnoreglowego [Breakdown of tree stand and spruce regeneration versus structure and dynamics of a Carpathian subalpine spruce forest]

2014 ◽  
Vol 82 ◽  
pp. 1-209 ◽  
Author(s):  
Jan Holeksa
Keyword(s):  
Large Scale ◽  
Strong Dependence ◽  
Mosaic Structure ◽  
Coarse Grained ◽  
Subalpine Forest ◽  
Forest Belt ◽  
Spruce Forest ◽  
Herb Layer ◽  
Structure And Dynamics ◽  
Subalpine Spruce Forest

Structure and dynamics of the Carpathian subalpine spruce forest was a subject of research conducted in Babia Góra National Park, protecting the highest massif in the whole West Beskids. The mosaic structure was simultaneously treated as a background for and a result of breakdown of spruce stand and spruce regeneration. The forest texture, dead trees, gaps, synusia of herb layer and spruce saplings were mapped over the area of 14,4 ha. Simultaneous mapping over the same and large area madę it possible to analyse the spatial relationships between all these phenomena and to reveal strong dependence between most of them. Particular attention was focused on spruce regeneration. It was stated that young spruces arę closely linked to microsites created by death of trees: windthrow mounds, logs and stumps in advanced stage of decay, and gaps larger than 200 m<sup>2</sup>. Seedlings and saplings were also relatively more abundant in patches dominated in herb layer by <em>Vaccinium myrtillus</em> or <em>Dryopteris dilatata</em> than in others. The conclusion was achieved that coarse-grained type of mosaic structure in subalpine spruce forest and large-scale disturbances not only arę the result of low resistance of congeneric and one-layered tree stands against wind, snów, glaze and insects. To large degree they are also shaped by condition of spruce regeneration. As a light-demanding species, spruce at high elevation needs large gaps for successfull regeneration. It leads to excessive thinning of stands and expose them to disruptive action of harsh climat in the subalpine forest belt.

scholarly journals Interannual variability of the ecosystem CO<sub>2</sub> fluxes at paludified spruce forest and ombrotrophic bog in southern taiga

2021 ◽  
Author(s):  
Vadim Mamkin ◽  
Vitaly Avilov ◽  
Dmitry Ivanov ◽  
Andrey Varlagin ◽  
Julia Kurbatova
Keyword(s):  
Interannual Variability ◽  
Environmental Conditions ◽  
Ecosystem Respiration ◽  
Growing Season ◽  
Southern Taiga ◽  
Co2 Uptake ◽  
Forest Site ◽  
Spruce Forest ◽  
Ombrotrophic Bog ◽  
Flux Measurements

Abstract. Climate warming in high latitudes impacts CO2 sequestration of northern peatlands through the changes in both production and decomposition processes. The response of the net CO2 fluxes between ecosystems and the atmosphere to the climate change and weather anomalies can vary across the forest and non-forest peatlands. To better understand the differences in CO2 dynamics at forest and non-forest boreal peatlands induced by changes in environmental conditions the estimates of interannual variability of the net ecosystem exchange (NEE), total ecosystem respiration (TER) and gross primary production (GPP) was obtained at two widespread peatland ecosystems – paludified spruce forest and adjacent ombrotrophic bog in the southern taiga of west Russia using 6-year of paired eddy covariance flux measurements. The period of measurements (2015–2020) was characterized by both positive and negative annual and growing season air temperature and precipitation anomalies. Flux measurements showed that in spite of the lower growing season TER (332…339 gC∙m−2) and GPP (442…464 gC∙m−2) rates the bog had a lower NEE (−132…−108) than the forest excepting the warmest and the wettest year of the period and was a sink of atmospheric CO2 in the selected years while the forest was a CO2 sink or source between years depending on the environmental conditions. Growing season NEE at the forest site was between −142 and 28 gC∙m−2, TER between 1135 and 1366 gC∙m−2 and GPP between 1207 and 1462 gC∙m−2. Annual NEE at the forest was between −62 and 145 gC∙m−2, TER between 1429 and 1652 gC∙m−2 and GPP between 1345 and 1566 gC∙m−2 respectively. Anomalously warm winter with sparse and thin snow cover lead to the increased GPP as well as lower NEE in early spring at forest and to the increased spring TER at the bog. Also, the shifting of the compensation point to the earlier dates at the forest and to the later dates at the bog following the warmest winter of the period was detected. This study suggest that the warming in winter can increase CO2 uptake of the paludified spruce forests of southern taiga in non-growing season.

scholarly journals Influences of Environmental Drivers on Land Cover Structure and its Long-Term Changes: a Case Study of the Villages of Malachov and Podkonice in Slovakia / Vliv Environmentálních Podmínek Na Strukturu Krajinného Pokryvu A Její Dlouhodobé Změny: Případová Studie Obcí Malachov A Podkonice Na Slovensku

2014 ◽  
Vol 22 (3) ◽  
pp. 29-41 ◽  
Author(s):  
Michal Druga ◽  
Vladimír Falťan
Keyword(s):  
Land Cover ◽  
Land Cover Change ◽  
Linear Models ◽  
Arable Land ◽  
Aerial Photographs ◽  
Environmental Drivers ◽  
Cadastral Maps ◽  
Cover Class

Abstract The influence of environmental drivers on long-term land cover changes in two mountainous villages in Central Slovakia is assessed in this paper using generalized linear models (GLM). Historical cadastral maps and aerial photographs were analyzed to describe the land cover change over five time horizons ranging from 1860 to the present, using the CORINE Land Cover classification. The hypothesis that higher slope, elevation and distance to settlement strongly influence lower intensities of land use was mostly confirmed, but geology was also identified as an important factor. The category of ‘forests’ was the most accounted for land cover class, while arable land and grassland were only considerably affected by the drivers in some periods. On the other hand, shrubs were almost completely unrelated to the investigated drivers. The areas of land cover change were not so well explained by the GLMs.

scholarly journals Predicting Rates of Inbreeding in Populations Undergoing Selection

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1851-1864 ◽  
Author(s):  
John A Woolliams ◽  
Piter Bijma
Keyword(s):  
Overlapping Generations ◽  
Linear Models ◽  
Selection Process ◽  
Correction Term ◽  
Random Mating ◽  
Nonrandom Mating ◽  
Selection Processes ◽  
Genetic Contributions ◽  
The Relationship

AbstractTractable forms of predicting rates of inbreeding (ΔF) in selected populations with general indices, nonrandom mating, and overlapping generations were developed, with the principal results assuming a period of equilibrium in the selection process. An existing theorem concerning the relationship between squared long-term genetic contributions and rates of inbreeding was extended to nonrandom mating and to overlapping generations. ΔF was shown to be ~¼(1 − ω) times the expected sum of squared lifetime contributions, where ω is the deviation from Hardy-Weinberg proportions. This relationship cannot be used for prediction since it is based upon observed quantities. Therefore, the relationship was further developed to express ΔF in terms of expected long-term contributions that are conditional on a set of selective advantages that relate the selection processes in two consecutive generations and are predictable quantities. With random mating, if selected family sizes are assumed to be independent Poisson variables then the expected long-term contribution could be substituted for the observed, providing ¼ (since ω = 0) was increased to ½. Established theory was used to provide a correction term to account for deviations from the Poisson assumptions. The equations were successfully applied, using simple linear models, to the problem of predicting ΔF with sib indices in discrete generations since previously published solutions had proved complex.

scholarly journals Detection of epileptic activity in presumably normal EEG

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Sara Baldini ◽  
Francesca Pittau ◽  
Gwenael Birot ◽  
Vincent Rochas ◽  
Miralena I Tomescu ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Epileptic Activity ◽  
Scalp Eeg ◽  
Vigilance State ◽  
Explained Variance ◽  
Long Term Monitoring ◽  
Interictal Discharges ◽  
The Individual ◽  
Term Monitoring

Abstract Monitoring epileptic activity in the absence of interictal discharges is a major need given the well-established lack of reliability of patients’ reports of their seizures. Up to now, there are no other tools than reviewing the seizure diary; however, seizures may not be remembered or dismissed voluntarily. In the present study, we set out to determine if EEG voltage maps of epileptogenic activity in individual patients can help to identify disease activity, even if their scalp EEG appears normal. Twenty-five patients with pharmacoresistant focal epilepsy were included. For each patient, 6 min of EEG with spikes (yes-spike) and without visually detectable epileptogenic discharges (no-spike) were selected from long-term monitoring recordings (EEG 31–37 channels). For each patient, we identified typical discharges, calculated their average and the corresponding scalp voltage map (‘spike-map’). We then fitted the spike-map for each patient on their (i) EEG epochs with visible spikes, (ii) epochs without any visible spike and (iii) EEGs of 48 controls. The global explained variance was used to estimate the presence of the spike-maps. The individual spike-map occurred more often in the spike-free EEGs of patients compared to EEGs of healthy controls (P = 0.001). Not surprisingly, this difference was higher if the EEGs contained spikes (P &lt; 0.001). In patients, spike-maps were more frequent per second (P &lt; 0.001) but with a shorter mean duration (P &lt; 0.001) than in controls, for both no-spike and yes-spike EEGs. The amount of spike-maps was unrelated to clinical variables, like epilepsy severity, drug load or vigilance state. Voltage maps of spike activity are present very frequently in the scalp EEG of patients, even in presumably normal EEG. We conclude that spike-maps are a robust and potentially powerful marker to monitor subtle epileptogenic activity.

scholarly journals Predictors of invertebrate biomass and rate of advancement of invertebrate phenology across eight sites in the North American Arctic

Polar Biology ◽  
2021 ◽  
Vol 44 (2) ◽  
pp. 237-257
Author(s):  
Rebecca Shaftel ◽  
Daniel J. Rinella ◽  
Eunbi Kwon ◽  
Stephen C. Brown ◽  
H. River Gates ◽  
...  
Keyword(s):  
Prey Availability ◽  
Population Level ◽  
The Arctic ◽  
Environmental Drivers ◽  
Chick Survival ◽  
The North ◽  
Phenological Mismatch ◽  
Nesting Sites ◽  
North American Arctic

AbstractAverage annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers affecting invertebrate availability, we modeled the biomass of invertebrates captured in modified Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confirmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively affected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey availability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level effects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.

scholarly journals Climate impacts on multidecadal <i>p</i>CO<sub>2</sub> variability in the North Atlantic: 1948–2009

2015 ◽  
Vol 12 (17) ◽  
pp. 15223-15244
Author(s):  
M. L. Breeden ◽  
G. A. McKinley
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Atlantic Multidecadal Oscillation ◽  
Climate Impacts ◽  
Co2 Uptake ◽  
Subpolar Gyre ◽  
The North ◽  
The North Atlantic

Abstract. The North Atlantic is the most intense region of ocean CO2 uptake. Here, we investigate multidecadal timescale variability of the partial pressure CO2 (pCO2) that is due to the natural carbon cycle using a regional model forced with realistic climate and pre-industrial atmospheric pCO2 for 1948–2009. Large-scale patterns of natural pCO2 variability are primarily associated with basin-averaged sea surface temperature (SST) that, in turn, is composed of two parts: the Atlantic Multidecadal Oscillation (AMO) and a long-term positive SST trend. The North Atlantic Oscillation (NAO) drives a secondary mode of variability. For the primary mode, positive AMO and the SST trend modify pCO2 with different mechanisms and spatial patterns. Warming with the positive AMO increases subpolar gyre pCO2, but there is also a significant reduction of dissolved inorganic carbon (DIC) due primarily to reduced vertical mixing. The net impact of positive AMO is to reduce pCO2 in the subpolar gyre. Through direct impacts on SST, the net impacts of positive AMO is to increase pCO2 in the subtropical gyre. From 1980 to present, long-term SST warming has amplified AMO impacts on pCO2.

scholarly journals Geographical variability of length-age structure of the Black Sea sprat Sprattus sprattus phalericus (Risso) (Pisces: Clupeidae) and intraspecific differentiation

2016 ◽  
Vol 1 (1) ◽  
pp. 24-35
Author(s):  
G. V. Zuyev ◽  
V. A. Bondarev ◽  
Yu. V. Samotoi
Keyword(s):  
Interannual Variability ◽  
Black Sea ◽  
Age Structure ◽  
The Black Sea ◽  
Population Parameter ◽  
Intraspecific Differentiation ◽  
Geographical Regions ◽  
The Crimea ◽  
Scientific Technical

Investigations of the Black Sea sprat intraspecific differentiation are the basis for the scientific substantiation of rational exploitation of its resource potential. This work is devoted to the study of spatial variability of length and age structure of sprat as specific population parameter reflecting its intraspecific differentiation. Our own data and materials of Scientific, Technical and Economic Committee for Fisheries (STECF) of the European Commission have been used. The first time long-term dynamics (2007–2012) and interannual variability of length and age structure of sprat in different geographical regions of the Black Sea (coastal waters of Bulgaria – Romania, Turkey and the Crimea) have been investigated. Differences of the long-term dynamics and interannual variability of length and age structure in these regions have been found. Sprat population from Bulgaria – Romania region is in better conditions (mean length 8.59 ± 0.01 cm; mean age 1.79  year), sprat population from Crimea region is in worse conditions (mean length 7.64 ± 0.01 cm; mean age 1.38 year). It has been shown that the main factor determining the interregional biological heterogeneity of sprat is the different fishery regulations. This fact disagrees with concept of united commercial sprat stock in the Black Sea.

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