Academic literature on the topic 'Above ground net primary production'
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Journal articles on the topic "Above ground net primary production"
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Pantel, A., J. T. Romo, and Y. Bai. "Above-ground net primary production of plains rough fescue [Festuca hallii (Vasey) Piper] after a single defoliation on five landform elements." Canadian Journal of Plant Science 91, no. 4 (July 2011): 689–96. http://dx.doi.org/10.4141/cjps2010-030.
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Pantel, A., Romo, J. T. and Bai, Y. 2011. Above-ground net primary production of plains rough fescue [ Festuca hallii (Vasey) Piper] after a single defoliation on five landform elements. Can. J. Plant Sci. 91: 689–696. Above-ground net primary production (ANPP) was determined for plains rough fescue [Festuca hallii (Vasey) Piper] following a single defoliation to 7.5 cm stubble height on five landform elements in the Northern Mixed Prairie. The landform elements included north aspect-concave slopes, north aspect-convex slopes, south aspect-concave slopes, south aspect-convex slopes, and level uplands. Above-ground net primary production was determined for 2 yr after defoliating plants in May through November. Above-ground net primary production after defoliation was not dependent on landform elements in the first (P=0.23) and second years (P=0.22) after defoliation. In the first year after June through September defoliation, ANPP was reduced 29 to 41% (P <0.01), whereas May, October, or November defoliation had no significant effect on ANPP. Above-ground net primary production did not vary significantly (P=0.61) among months of defoliation in the second year after defoliation. Less ANPP in the first year after June through September defoliation indicates the need for ≥1 yr of deferred use to allow plants to regain their production potential. Unaffected ANPP after May, October, or November defoliation suggests plains rough fescue can be grazed annually. Recuperation of ANPP after defoliation depends on the month of the year in which plains rough fescue is defoliated, but not on landform elements in the Northern Mixed Prairie.
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Chen, Yuxiang, Gilzae Lee, Pilzae Lee, and Takehisa Oikawa. "Model analysis of grazing effect on above-ground biomass and above-ground net primary production of a Mongolian grassland ecosystem." Journal of Hydrology 333, no. 1 (January 2007): 155–64. http://dx.doi.org/10.1016/j.jhydrol.2006.07.019.
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Aragão, L. E. O. C., Y. Malhi, D. B. Metcalfe, J. E. Silva-Espejo, E. Jiménez, D. Navarrete, S. Almeida, et al. "Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils." Biogeosciences 6, no. 12 (December 1, 2009): 2759–78. http://dx.doi.org/10.5194/bg-6-2759-2009.
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Abstract. The net primary productivity (NPP) of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1) How do Amazonian forests allocate productivity among its above- and below-ground components? (2) How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3 Mg C ha−1 yr−1 (mean±standard error), at a white sand plot, and 17.0±1.4 Mg C ha−1 yr−1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9 Mg C ha−1 yr−1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above- and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content.
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Aragão, L. E. O. C., Y. Malhi, D. B. Metcalfe, J. E. Silva-Espejo, E. Jiménez, D. Navarrete, S. Almeida, et al. "Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils." Biogeosciences Discussions 6, no. 1 (February 25, 2009): 2441–88. http://dx.doi.org/10.5194/bgd-6-2441-2009.
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Abstract. The net primary productivity (NPP) of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1) How do Amazonian forests allocate productivity among its above- and below-ground components? (2) How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3 Mg C ha−1 yr−1 (mean±standard error), at a white sand plot, and 17.0±1.4 Mg C ha−1 yr−1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9 Mg C ha−1 yr−1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above- and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content.
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Chambers, Jeffrey Q., Joaquim dos Santos, Ralfh J. Ribeiro, and Niro Higuchi. "Tree damage, allometric relationships, and above-ground net primary production in central Amazon forest." Forest Ecology and Management 152, no. 1-3 (October 2001): 73–84. http://dx.doi.org/10.1016/s0378-1127(00)00591-0.
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Siche, Raúl, and Enrique Ortega. "Emergy and value of the net primary production (NPP) above ground in natural areas." Ecological Questions 10 (July 21, 2008): 99. http://dx.doi.org/10.12775/v10090-009-0011-2.
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Qin, Xiao-jing, Jiang-tao Hong, Xing-xing Ma, and Xiao-dan Wang. "Global patterns in above-ground net primary production and precipitation-use efficiency in grasslands." Journal of Mountain Science 15, no. 8 (August 2018): 1682–92. http://dx.doi.org/10.1007/s11629-017-4772-6.
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Baeza, S., F. Lezama, G. Piñeiro, A. Altesor, and J. M. Paruelo. "Spatial variability of above-ground net primary production in Uruguayan grasslands: a remote sensing approach." Applied Vegetation Science 13, no. 1 (February 2010): 72–85. http://dx.doi.org/10.1111/j.1654-109x.2009.01051.x.
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Szumigalski, Anthony R., and Suzanne E. Bayley. "Net above-ground primary production along a bog-rich fen gradient in Central Alberta, Canada." Wetlands 16, no. 4 (December 1996): 467–76. http://dx.doi.org/10.1007/bf03161336.
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Gibson, N. "The Environments and Primary Production of Cushion Species at Mt Field and Mt Wellington, Tasmania." Australian Journal of Botany 38, no. 3 (1990): 229. http://dx.doi.org/10.1071/bt9900229.
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Primary production of four species of alpine cushion plants were studied over a 2-year period. The climate of these areas was found to be severe but with a high degree of variability on a seasonal and yearly basis. The growing season at the higher altitude sites generally exceeded 6 months. Net above ground primary production of the four cushion species ranged from 282 to 709 g m-2 year-1. Reproductive effort fluctuated between species and years, ranging from 0 to 30% of net above ground production. Patterns in dry matter accumulation suggest no individual species would show consistently superior growth rates under present climatic conditions. Soil moisture and soil nutrient status was found to be similar between all sites. Altitude of the sites (830-1400 m) was found to be strongly correlated with the timing of flowering and/or seed set but appeared to have little effect on net primary production.
Dissertations / Theses on the topic "Above ground net primary production"
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Eisfelder, Christina. "Modelling Net Primary Productivity and Above-Ground Biomass for Mapping of Spatial Biomass Distribution in Kazakhstan." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-119964.
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Biomass is an important ecological variable for understanding the responses of vegetation to the currently observed global change. The impact of changes in vegetation biomass on the global ecosystem is also of high relevance. The vegetation in the arid and semi-arid environments of Kazakhstan is expected to be affected particularly strongly by future climate change. Therefore, it is of great interest to observe large-scale vegetation dynamics and biomass distribution in Kazakhstan.
At the beginning of this dissertation, previous research activities and remote-sensing-based methods for biomass estimation in semi-arid regions have been comprehensively reviewed for the first time. The review revealed that the biggest challenge is the transferability of methods in time and space. Empirical approaches, which are predominantly applied, proved to be hardly transferable. Remote-sensing-based Net Primary Productivity (NPP) models, on the other hand, allow for regional to continental modelling of NPP time-series and are potentially transferable to new regions.
This thesis thus deals with modelling and analysis of NPP time-series for Kazakhstan and presents a methodological concept for derivation of above-ground biomass estimates based on NPP data. For validation of the results, biomass field data were collected in three study areas in Kazakhstan. For the selection of an appropriate model, two remote-sensing-based NPP models were applied to a study area in Central Kazakhstan. The first is the Regional Biomass Model (RBM). The second is the Biosphere Energy Transfer Hydrology Model (BETHY/DLR). Both models were applied to Kazakhstan for the first time in this dissertation. Differences in the modelling approaches, intermediate products, and calculated NPP, as well as their temporal characteristics were analysed and discussed.
The model BETHY/DLR was then used to calculate NPP for Kazakhstan for 2003–2011. The results were analysed regarding spatial, intra-annual, and inter-annual variations. In addition, the correlation between NPP and meteorological parameters was analysed. In the last part of this dissertation, a methodological concept for derivation of above-ground biomass estimates of natural vegetation from NPP time-series has been developed. The concept is based on the NPP time-series, information about fractional cover of herbaceous and woody vegetation, and plants’ relative growth rates (RGRs). It has been the first time that these parameters are combined for biomass estimation in semi-arid regions. The developed approach was finally applied to estimate biomass for the three study areas in Kazakhstan and validated with field data.
The results of this dissertation provide information about the vegetation dynamics in Kazakhstan for 2003–2011. This is valuable information for a sustainable land management and the identification of regions that are potentially affected by a changing climate. Furthermore, a methodological concept for the estimation of biomass based on NPP time-series is presented. The developed method is potentially transferable. Providing that the required information regarding vegetation distribution and fractional cover is available, the method will allow for repeated and large-area biomass estimation for natural vegetation in Kazakhstan and other semi-arid environments.
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Eisfelder, Christina [Verfasser], Manfred F. [Akademischer Betreuer] Buchroithner, Stefan [Akademischer Betreuer] Dech, and Martin [Akademischer Betreuer] Kappas. "Modelling Net Primary Productivity and Above-Ground Biomass for Mapping of Spatial Biomass Distribution in Kazakhstan / Christina Eisfelder. Gutachter: Manfred F. Buchroithner ; Stefan Dech ; Martin Kappas." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://d-nb.info/1068153679/34.
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Kho, Lip Khoon. "Carbon cycling in a Bornean tropical forest : exploring carbon allocation and cycling of tropical forest in the 52-ha Lambir Hills forest dynamics plot." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:bfa1f206-97bf-4bcd-a148-521506225c90.
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The tropical forests on the island of Borneo are among of the richest in the world in terms of tree diversity, and their capacity to store a large reservoir of carbon. The Southeast Asian forests are fundamentally different from Neotropical and African forests, with their single-family dominance by dipterocarp trees, and with inherently greater stature and biomass. The carbon productivity and allocation in Asian tropical forests is still poorly quantified, and their responses to environmental drivers are still poorly understood. Almost all recent advances in tropical forest carbon cycling research have occurred in the Neotropics, with very few studies in Asia. The principal aim of this thesis is to quantify the carbon budget of a lowland dipterocarp forest in the Lambir Hills National Park, Miri, Sarawak, Malaysian Borneo. I examined and explored the productivity and carbon cycling processes and their responses to environmental factors across two major and contrasting soil types, in particular the clay and sandy loam soils. I recorded and analysed the Net Primary Productivity (NPP) and respiration for the above- and below-ground components, and observed the responses to seasonal variation and environmental drivers. Total soil respiration was relatively high and contributed a great deal to ecosystem respiration. Variation in soil respiration rates appeared closely related to soil moisture content. I found a strong diurnal cycle in soil respiration. On the basis of the first soil carbon dioxide (CO2) efflux partitioning study undertaken in a tropical forest, the diurnal cycle in total soil respiration appeared to be entirely driven by the diurnal cycle in litter respiration, and in turn litter is strongly controlled by moisture. There was little seasonal variation in allocation of net primary productivity (NPP), but there was evidence showing potential inter-annual variability for several components of NPP. Further, the allocation of NPP showed a strong seasonal shift between the forest plots on clay and sandy loam soils. Combining all the data measured and obtained in this D.Phil. thesis, the overall carbon budget assessed in this lowland dipterocarp forest showed a high level of agreement with other studies in Asia using micrometeorological techniques and the situation appears to be comparable to tropical forests in Amazonia. The key difference is that the aboveground NPP is higher and is the largest component contributing to the overall carbon budget, with relatively higher carbon use efficiency (CUE). The lowland dipterocarp forest in Lambir shows higher allocation in the above-ground NPP, and there were also differences in NPP and its allocation between sandy and clay-rich plots.
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"Effects of Water Holding Capacity and Precipitation on Above Ground Net Primary Production." Master's thesis, 2019. http://hdl.handle.net/2286/R.I.53849.
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abstract: Aboveground net primary production (ANPP) is an important ecosystem process that, in drylands, is most frequently limited by water availability. Water availability for plants is in part controlled by the water holding capacity of soils. Available water holding capacity (AWHC) of soils is strongly influenced by soil texture and depth. This study drew upon localized rain gauge data and four data-sets of cover-line and biomass data to estimate ANPP and to determine annual precipitation (PPT). I measured soil depth to caliche and texture by layer of 112 plots across the four landscape units for which estimation of ANPP were available. A pedotransfer function was used to estimate AWHC from soil depth increments to depth of caliche measurements and texture analysis. These data were analyzed using simple and multivariate regression to test the effect of annual precipitation and available water holding capacity on aboveground net primary production. Soil texture remained constant among all plots (sandy loam) and depth to caliche varied from 15.16 cm to 189 cm. AWHC and the interaction term (PPT*AWHC) were insignificant (p=0.142, p=0.838) and annual PPT accounted for 18.4% of the variation in ANPP. The y-intercept was significantly different for ANPP ~ annual PPT when considering AWHC values either above or below 3 cm. Shrub ANPP was insensitive to precipitation regardless of AWHC (R2=-0.012, R2=0.014). Results from this study indicate that a model incorporating annual PPT and AWHC may not serve as a good predictor for ANPP at a site level where there is little variation in soil texture.Dissertation/Thesis
Masters Thesis Sustainability 2019
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Adamek, Markus. "Effects of increased nitrogen input on the net primary production of a tropical lower montane rain foest, Panama." Doctoral thesis, 2009. http://hdl.handle.net/11858/00-1735-0000-0006-B124-0.
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Eisfelder, Christina. "Modelling Net Primary Productivity and Above-Ground Biomass for Mapping of Spatial Biomass Distribution in Kazakhstan." Doctoral thesis, 2012. https://tud.qucosa.de/id/qucosa%3A27091.
Full textAbstract:
Biomass is an important ecological variable for understanding the responses of vegetation to the currently observed global change. The impact of changes in vegetation biomass on the global ecosystem is also of high relevance. The vegetation in the arid and semi-arid environments of Kazakhstan is expected to be affected particularly strongly by future climate change. Therefore, it is of great interest to observe large-scale vegetation dynamics and biomass distribution in Kazakhstan.
At the beginning of this dissertation, previous research activities and remote-sensing-based methods for biomass estimation in semi-arid regions have been comprehensively reviewed for the first time. The review revealed that the biggest challenge is the transferability of methods in time and space. Empirical approaches, which are predominantly applied, proved to be hardly transferable. Remote-sensing-based Net Primary Productivity (NPP) models, on the other hand, allow for regional to continental modelling of NPP time-series and are potentially transferable to new regions.
This thesis thus deals with modelling and analysis of NPP time-series for Kazakhstan and presents a methodological concept for derivation of above-ground biomass estimates based on NPP data. For validation of the results, biomass field data were collected in three study areas in Kazakhstan. For the selection of an appropriate model, two remote-sensing-based NPP models were applied to a study area in Central Kazakhstan. The first is the Regional Biomass Model (RBM). The second is the Biosphere Energy Transfer Hydrology Model (BETHY/DLR). Both models were applied to Kazakhstan for the first time in this dissertation. Differences in the modelling approaches, intermediate products, and calculated NPP, as well as their temporal characteristics were analysed and discussed.
The model BETHY/DLR was then used to calculate NPP for Kazakhstan for 2003–2011. The results were analysed regarding spatial, intra-annual, and inter-annual variations. In addition, the correlation between NPP and meteorological parameters was analysed. In the last part of this dissertation, a methodological concept for derivation of above-ground biomass estimates of natural vegetation from NPP time-series has been developed. The concept is based on the NPP time-series, information about fractional cover of herbaceous and woody vegetation, and plants’ relative growth rates (RGRs). It has been the first time that these parameters are combined for biomass estimation in semi-arid regions. The developed approach was finally applied to estimate biomass for the three study areas in Kazakhstan and validated with field data.
The results of this dissertation provide information about the vegetation dynamics in Kazakhstan for 2003–2011. This is valuable information for a sustainable land management and the identification of regions that are potentially affected by a changing climate. Furthermore, a methodological concept for the estimation of biomass based on NPP time-series is presented. The developed method is potentially transferable. Providing that the required information regarding vegetation distribution and fractional cover is available, the method will allow for repeated and large-area biomass estimation for natural vegetation in Kazakhstan and other semi-arid environments.
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Runyon, John R. "Environmental limits on above-ground production : observations from the Oregon transect." Thesis, 1992. http://hdl.handle.net/1957/37133.
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"Nematode Herbivory as a Mechanism Behind the Influence of Precipitation on the Partitioning of Net Primary Production between Above and Belowground Components." Master's thesis, 2018. http://hdl.handle.net/2286/R.I.49279.
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abstract: Aboveground net primary production (ANPP) and belowground net primary production (BNPP) may not be influenced equally by the same factors in arid grasslands. Precipitation is known to affect ANPP and BNPP, while soil fauna such as nematodes affect the BNPP through herbivory and predation. This study on black grama grass (Bouteloua eriopoda) in the Chihuahuan Desert investigates the effects of precipitation and nematode presence or absence on net primary production (NPP) as well as the partitioning between the aboveground and belowground components, in this case, the fraction of total net primary production occurring belowground (fBNPP). I used a factorial experiment to investigate the effects of both precipitation and nematode presence on the components of NPP. I used rainout shelters and an irrigation system to alter precipitation totals, while I used defaunated and re-inoculated soil for the nematode treatments. Precipitation treatment and seasonal soil moisture had no effect on the BNPP and a nonsignificant positive effect on the ANPP. The fBNPP decreased with increasing precipitation and seasonal soil moisture, though without a significant effect. No predator nematodes were found in any of the microcosms at the end of the experiment, though other functional groups of nematodes, including herbivores, were found in the microcosms. Total nematode numbers did not vary significantly between nematode treatments, indicating that the inoculation process did not last for the whole experiment or that nematodes had little plant material to eat and resulted in low population density. Nematode presence did not affect the BNPP, ANPP, or the fBNPP. There were no significant interactions between precipitation and nematode treatment. The results are inconclusive, possibly as a result of ecosystem trends during an unusually high precipitation year, as well as the very low NPP values in the experiment that correlated with low nematode community numbers.Dissertation/Thesis
Masters Thesis Biology 2018
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Müller-Haubold, Hilmar. "Climate response of above- and belowground productivity and allocation in European beech." Doctoral thesis, 2014. http://hdl.handle.net/11858/00-1735-0000-0022-5FFB-6.
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Die Rotbuche (Fagus sylvatica L.) ist die bestimmende Baumart der potentiell natürlichen Vegetation in den Wäldern Mittel- und Westeuropas die ökonomisch bedeutsamste Laubbaumart Deutschlands. Obwohl diese spät-sukzessionelle Baumart über eine hohe physiologische Toleranz gegenüber einem weiten Spektrum klimatischer Wuchsbedingungen verfügt, wird die Buche gegenüber anderen temperaten Laubbaumarten als relativ trockensensitiv eingeschätzt. Da im Zuge des globalen Klimawandels mit einer Verschlechterung der klimatischen Wasserbilanz und mit einer Zunahme sommerlicher Trockenperioden gerechnet wird, wird die zukünftige Rolle der Rotbuche in der europäischen Forstwirtschaft derzeit intensiv diskutiert. Diese Studie hatte zum Ziel, hydrologische und klimatische Einflüsse auf die Produktivität und die Vitalität der Rotbuche zu untersuchen. Hierdurch sollen grundlegende Mechanismen der Trockenstressantwort bei dieser trocken-sensitiven Art identifiziert, und Rückschlüsse auf zukünftige Klimaantworten von Buchenbeständen ermöglicht werden. Zu diesem Zweck wurde die ober- und unterirdische Biomasseproduktion von 12 Buchenaltbeständen im Norddeutschen Tiefland entlang eines natürlichen Niederschlagsgradienten (543-816 mm a-1) auf einheitlichem geologischen Substrat ermittelt. Um den zusätzlichen Einfluss der Wasserspeicherkapazität der Böden zu berücksichtigen, wurden Paare von Buchenbeständen untersucht, die unter nahezu identischen klimatischen Bedingungen, jedoch auf Böden unterschiedlicher Textur (sandige versus lehmig-sandige Böden) stockten. Einflüsse der Wasserverfügbarkeit und klimatischer Variationen auf das Wachstum wurden untersucht unter Berücksichtigung (i) der gesamten ober- und unterirdischen Biomasseproduktion, (ii) der Dynamik von Ressourcen-Allokation und Kohlenstoff-Partitionierung, sowie (iii) der Morphologie wasseraufnehmender und -abgebender Oberflächen.
Unerwarteterweise zeigte sich die gesamte Produktivität von Buchen-Altbeständen nur geringfügig von Veränderungen der hydrologischen Regime entlang des Gradienten beeinflusst. Trotz deutlicher Unterschiede in der jährlichen Wasserverfügbarkeit nahmen die oberirdische und die gesamte Biomasseproduktion auf den trockeneren Flächen des Transektes nicht ab. Allerdings führten ausgeprägte früh-sommerliche Wasserdefizite (in den Monaten Juni und Juli) zu deutlichen Einbußen der oberirdischen Biomasseproduktion, und insbesondere der Stammholzproduktion. Entlang des untersuchten Gradienten konnte eine ausgeprägte, kontinuierliche Verschiebung der Allokationsmuster festgestellt werden: Mit abnehmender Wasserverfügbarkeit nahm die Feinwurzelproduktion zu und das Verhältnis von oberirdischer:unterirdischer Biomasseproduktion ab. Anders als oberirdische Komponenten zeigte die Feinwurzelproduktion eine hohe Sensibilität gegenüber Unterschieden hinsichtlich hydrologischer Regime. In Übereinstimmung mit der Optimalitätstheorie der pflanzlichen Ressourcennutzung konnte dieses Allokationsverhalten in sowohl in Reaktion auf veränderte Niederschläge, als auch in Antwort auf auch veränderte Wasserspeicherkapazitäten beobachtet werden. Allokative Anpassungsmechanismen an Wassermangel wurden im Feinwurzelbereich zusätzlich durch morphologische Plastizität (Zunahme im Verhältnis von Oberfläche: Biomasse) und durch Regulierung der räumlichen Verteilung (zunehmende Konzentrierung von Feinwurzeln in der organischen Auflage) komplementiert. Im Gegensatz zu diesen komplexen unterirdischen Trockenheits-Antworten konnten keinerlei Anpassungen der Blattmorphologie an veränderte hydrologische Bedingungen festgestellt werden.
Neben Reaktionen auf Wasserverfügbarkeit wurde die Fruchtbildung als zweiter wesentlicher Einfluss auf das Allokationsverhalten der Buche erkannt. Eine deutliche Ressourcen-Allokation zu Gunsten der Fruchtentwicklung beeinträchtigte maßgeblich das oberirdische vegetative Wachstum, insbesondere den Stammholzzuwachs. Auf Grund einer hohen Attraktionsstärke der Früchte gegenüber C und N führte zunehmende Fruktifizierung auch zu einer Gewichts- (und Größen-) Abnahme der Einzelblätter und somit zu reduzierter Bildung von Blattmasse und Bestandesblattfläche (LAI). Neben dieser Abnahme an assimilierender Blattoberfläche führte auch eine deutliche Senkung der Blatt-Stickstoffgehalte in Folge der reproduktiven Ressourcenwidmung mutmaßlich zu einer Verschlechterung der C-Bilanz, sowohl im Mast- als auch im Folgejahr. Eine Analyse klimatischer Einflussfaktoren auf das Mastverhalten legt nahe, dass die Blütenbildung der Buche durch Überschreitung eines Schwellenwertes der Kohlenstoffassimilation im Frühsommer (Juni-Juli) induziert wird.
Sofern diese Schlüsse zutreffen, unterliegt das zeitliche Muster der Fruktifikations-Antwort auf Witterungsauslöser einer Rückkopplungskontrolle durch pflanzliche Stickstoff-Dynamik. Vor dem Hintergrund anhaltend erhöhter Stickstoffdepositionen ergäbe sich aus diesem Mechanismus eine zusätzliche Belastung für das zukünftige vegetative Wachstum der Buche.
Es ist anzunehmen, dass die in dieser Studie belegte hohe allokative Plastizität in Altbäumen Fagus sylvatica dazu befähigt, ihre hohe Konkurrenzkraft in einem breiten Spektrum hydrologischer Regime zu entfalten. Darüber hinaus werden die hier dargestellten Mechanismen einer langfristigen Trockenheitsanpassung mutmaßlich zu einer gesteigerten Resistenz und Resilienz von Buchen-Altbeständen gegenüber Ereignissen extremer Sommertrockenheit beitragen.
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Kotowska, Martyna Małgorzata. "Carbon pools and sequestration in vegetation, litter dynamics and hydraulic anatomic properties in rainforest transformation systems in Indonesia." Doctoral thesis, 2015. http://hdl.handle.net/11858/00-1735-0000-0028-863B-9.
Full textBooks on the topic "Above ground net primary production"
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Primary production in arable crops: Above-ground growth dynamics, net production and nitrogen uptake. Uppsala: Swedish University of Agricultural Sciences, Dept. of Ecology and Environmental Research, 1987.
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Runyon, John R. Environmental limits on above-ground production: Observations from the Oregon transect. 1992.
Find full textBook chapters on the topic "Above ground net primary production"
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Vitt, Dale H. "Estimating Moss and Lichen Ground Layer Net Primary Production in Tundra, Peatlands, and Forests." In Principles and Standards for Measuring Primary Production, 82–105. Oxford University Press, 2007. http://dx.doi.org/10.1093/acprof:oso/9780195168662.003.0006.
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Madera, Petr, Diana Lopez, and Martin Senfeldr. "The Above-Ground Biomass Production and Distribution in White Willow Community During 11 Years of Primary Succession." In Biomass and Remote Sensing of Biomass. InTech, 2011. http://dx.doi.org/10.5772/19990.
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Milchunas, Daniel G., and William K. Lauenroth. "Effects of Grazing on Abundance and Distribution of Shortgrass Steppe Consumers." In Ecology of the Shortgrass Steppe. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195135824.003.0022.
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Although livestock are the most obvious consumers on the shortgrass steppe, they are certainly not the only consumers. However, livestock may influence the other consumers in a number of different ways. They may directly compete for food resources with other aboveground herbivores. There is behavioral interference between livestock and some species of wildlife (Roberts and Becker, 1982), but not others (Austin and Urness, 1986). The removal of biomass by livestock alters canopy structure (physiognomy) and influences microclimate. Bird, small-mammal, and insect species can be variously sensitive to these structural alterations (Brown, 1973; Cody, 1985; MacArthur, 1965; Morris, 1973; Rosenzweig et al., 1975; Wiens, 1969). There are both short- and long-term effects of grazing on plant community species composition, primary production, and plant tissue quality. Belowground consumers can also be affected by the effects of grazing on soil water infiltration, nutrient cycling, carbon allocation patterns of plants, litter accumulation, and soil temperature. The overall effects of livestock on a particular component of the native fauna can be negative or can be positive through facilitative relationships (Gordon, 1988). In this chapter we assess the effects of cattle grazing on other above- and belowground consumers, on the diversity and relative sensitivity of these groups of organisms, and on their trophic structure. We first present some brief background information on plant communities of the shortgrass steppe and on the long-term grazing treatments in which many of the studies reported herein were conducted. Details on the plant communities are presented by Lauenroth in chapter 5 (this volume), grazing effects on plant communities by Milchunas et al. in chapter 16 (this volume); and grazing effects on nutrient distributions and cycling by Burke et al. in chapter 13 (this volume). The physiognomy of the shortgrass steppe is indicated in its name. The dominant grasses (Bouteloua gracilis and Buchloë dactyloides), forb (Sphaeralcea coccinea), and carex (Carex eleocharis) have the majority of their leaf biomass within 10 cm of the ground surface. A number of less abundant midheight grasses and dwarf shrubs are sparsely interspersed among the short vegetation, but usually much of their biomass is within 25 cm of the g round. Basal cover of vegetation typically totals 25% to 35%, and is greater in long-term grazed than in ungrazed grassland. Bare ground (more frequent on grazed sites) and litter-covered ground (more frequent on ungrazed sites) comprise the remainder of the soil surface (Milchunas et al., 1989).
Conference papers on the topic "Above ground net primary production"
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Diao, Zhaoyan, Shihai Lv, Chaoyang Feng, Derong Su, Liang Sun, and Xue Tian. "The Correction ground spectral model for estimating above-ground net primary productivity at the peak of growing season on Meadow Steppe, Hulunbeier, Inner Mongolia, China." In 2014 Third International Conference on Agro-Geoinformatics. IEEE, 2014. http://dx.doi.org/10.1109/agro-geoinformatics.2014.6910596.
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Zhang, Dalin, Changliang Liu, Libo Qian, Guanghui Su, and Suizheng Qiu. "Numerical Research on Steady Coupling of Neutronics and Thermal-Hydraulics for a Molten Salt Reactor." In 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48096.
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The Molten Salt Reactor (MSR), which is one of the ‘Generation IV’ concepts, can be used for production of electricity, actinide burning, production of hydrogen, and production of fissile fuels. In this paper, a single-liquid-fueled MSR was selected for conceptual research. For this MSR, a ternary system of 15%LiF-58%NaF-27%BeF2 was proposed as the reactor fuel solvent, coolant and also moderator with ca. 1 mol% UF4 dissolving in it, which circulates through the whole primary loop accompanying fission reaction only in the core. The fuel salt flow makes the MSR different from the conventional reactors using solid fissile materials, and makes the neutronics and thermal-hydraulic coupled strongly, which plays the important role in the research of reactor safety analysis. Therefore, it’s necessary to study the coupling of neutronics and thermal-hydraulic. The theoretical models of neutronics and thermal-hydraulics under steady condition were conducted and calculated by numerical method in this paper. The neutronics model consists of two group neutron diffusion equations for fast and thermal neutron fluxes, and balance equations for six-group delayed neutron precursors considering flow effect. The thermal-hydraulic model was founded on the base of the fundamental conservation laws: the mass, momentum and energy conservation equations. These two models were coupled through the temperature and heat source. The spatial discretization of the above models is based on the finite volume method (FVM), and the thermal-hydraulic equations are computed by SIMPLER algorithm with domain extension method on the staggered grid system. The distribution of neutron fluxes, the distribution of the temperature and velocity and the distribution of the delayed neutron precursors in the core were obtained. The numerical calculated results show that, the fuel salt flow has little effect to the distribution of fast and thermal neutron fluxes and effective multiplication factor; however, it affects the distribution of the delayed neutron precursors significantly, especially long-lived one. In addition, it could be found that the delayed neutron precursors influence the neutronics slightly under the steady condition, and the flow could remove the heat generated by the neutron reactions easily to ensure the reactor safe. The obtained results serve some valuable information for the research and design of this new generation reactor.
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Esquitin, Yosafat, Chima Chima, Ricardo Vasques, Paul Hazel, and Brian Schwanitz. "Securing Zonal Isolation Across a Highly Depleted GoM Deep Water Reservoir." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206374-ms.
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Abstract Effective zonal isolation within a layered reservoir in the Gulf of Mexico is a necessity to meet regulations for stacked reservoirs and to maximize total recoverables. Effective zonal isolation also ensures maximum production is achieved via a high-pressure proppant fracture treatment. A primary cement operation of a 10 1/8" production liner (within a 12 ¼" drilled hole section) was challenging due to a combination of high equivalent circulation density (ECD) and potential losses across a layered GOM reservoir. One layer had potential and significant depletion up to 8,000 psi. Critical well parameter considerations were: maintaining the liner burst of 18,200 psi, maximizing rotation and reciprocation capability of the liner, minimizing the impact on circulation and ECD, and ensuring compatibility with the mud systems. Following careful job planning, including the analysis of caliper data from logging while drilling (LWD) for the optimum placement, two metal expandable packers (MEPs) were installed on the 10 1/8" liner. The MEPs were positioned to straddle the highly depleted layer (one above and one below) in the 12 ¼" open hole section. The liner was deployed, and the cement operation was executed with minimal ECD impact from the inclusion of the MEPs. Surface pressure was applied to create sufficient differential pressure across the 10 1/8" liner wall to hydraulically expand the MEPs quickly under full surface control. This paper covers the qualification, planning, and deployment of MEPs to provide cement assurance (CA) for zonal isolation and improve the effectiveness of contingency cement squeezes. Though this technology has been used in other regions for several years, this was the first deployment in the Gulf of Mexico (GOM). The solution improved the probability of success of the primary cement job, negating the requirement for a remedial cement squeeze. The decision to run MEPs was based on the estimated cost savings of 3.5 million USD for remedial squeeze operations, a value proposition that did not account for the net present value (NPV) gain, due to improved fracture placement, compared to the case of poor cement isolation.
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Mosse, Laurent, Stephen Pell, and Thomas Neville. "IDENTIFICATION OF BREAKOUT BEHIND CASING: METHODOLOGY TO OBTAIN OPENHOLE EQUIVALENT CALIPER MEASUREMENTS THROUGH SLOTTED LINER USING THE DENSITY TOOL." In 2021 SPWLA 62nd Annual Logging Symposium Online. Society of Petrophysicists and Well Log Analysts, 2021. http://dx.doi.org/10.30632/spwla-2021-0046.
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Growth in the coal seam gas industry in Queensland, Australia, has been rapid over the past fifteen years, with greater than USD 70 billion invested in three liquified natural gas export projects supplied by produced coal seam gas. Annual production is of the order of 40 Bscm or 1,500 PJ, with approximately 80% of this coming from the Jurassic Walloon Coal Measures of the Surat Basin and 20% from Permian coal measures of the Bowen Basin. The Walloon Coal Measures are characterized by multiple thin coal seams making up approximately 10% of the total thickness of the unit. A typical well intersects 10 to 20 m of net coal over a 200 to 300 m interval, interbedded with lithic-rich sandstones, siltstones, and carbonaceous mudstones. The presence of such a significant section of lithic interburden within the primary production section has led to a somewhat unusual completion strategy. To maximize connection to the gas-bearing coals, uncemented slotted liners are used; however, this leaves fluid-sensitive interburden exposed to drilling, completion, and produced formation fluids over the life of a well. External swellable packers and blank joints are therefore used to isolate larger intervals of interburden and hence minimize fines production. Despite these efforts, significant fines production still occurs, which leads to failure of artificial lift systems and the need for expensive workovers or lost wells. Fines production has major economic implications, with anecdotal reports suggesting up to 40% of progressive cavity pump artificial lift systems in Walloon Coal Measures producers may be down at any one time. The first step in solving this problem is to identify the extent and distribution of fines production. The wellbore completion strategy above, however, precludes use of mechanical calipers to identify fines production-related wellbore enlargement. A new caliper-behind-liner technique has therefore been developed using a multiple-detector density tool. Data from the shorter spacing detectors is used to characterize the properties of the liner as well as the density of the annular material. This is particularly important to evaluate as the annulus fill varies between gas, formation water, drilling and completion fluids, and accumulated fines. The longer spacing detector measurements are then used in conjunction with pre-existing open-hole formation density measurement to determine the thickness of the annulus, and hence hole size, compensating for liner and annulus properties. This methodology has been applied to several wells completed in the Walloon Coal Measures. Results have demonstrated the ability to identify zones of borehole enlargement behind slotted liner, as well as intervals of either gas or fines accumulation in the annulus. In addition, the technique has been successful in verifying the placement of swellable packers and their integrity. The application of this solution has been used to drive improvements in the design of in-wellbore completion programs and in the future will help drive recompletion decisions and trigger proactive workovers.