Dissertations / Theses: 'Litter production and decomposition'

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Jali, Dulima Binti. "Nitrogen mineralisation, litter production and cellulose decomposition in tropical peat swamps." Thesis, Royal Holloway, University of London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269744.

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Enriquez, Luis Villavicencio. "The role of canopy structure in leaf litter production, quality and decomposition in rustic and traditional coffee systems and forests in Mexico." Thesis, Bangor University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510270.

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Altinalmazis, kondylis Andreas. "Tree diversity effects on root production, decomposition and nutrient cycling under global change." Thesis, Bordeaux, 2021. http://www.theses.fr/2021BORD0067.

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L'hypothèse de l'assurance prévoit que les forêts composées de mélanges d'espèces d'arbres pourraient mieux résister aux conditions environnementales stressantes que les forêts composées d'une seule espèce d'arbre. La majorité des travaux antérieurs ont testé cette hypothèse en se focalisant sur la productivité et les variables de réponse associées sans prendre en compte les processus souterrains. L’objectif principal de ma thèse était d’étudier l’effet de la diversité des espèces d’arbres sur les processus souterrains impliqués dans la décomposition des racines à travers des gradients climatiques. J'ai émis l'hypothèse que le mélange d'espèces ayant des systèmes racinaires contrastés entraînerait une faible compétition souterraine, et se traduirait par la production de plus biomasse de racines fines. En outre, j'ai émis l'hypothèse que les racines ayant des caractéristiques chimiques et morphologiques contrastées dans les peuplements mixtes se décomposent plus rapidement. Dans des conditions de stress hydrique, j'ai émis l'hypothèse d'une décomposition plus lente mais d’une atténuation des mélanges d'arbres sur la décomposition en raison de l'amélioration des conditions micro-environnementales. Pour tester ces hypothèses, j'ai examiné la variation des caractéristiques fonctionnelles des racines et leurs conséquences sur les flux de C, N et P à l'échelle de l'écosystème à travers l’étude de : 1) la ségrégation verticale des racines et la biomasse des racines fines, 2) la dynamique des racines fines et les flux de nutriments associés et 3) la décomposition des racines fines et des feuilles mortes. Dans ce cadre, trois deux expériences de terrain ont été réalisé, l'une avec une expérience de plantation d'arbres de 10 ans avec du bouleau et du pin près de Bordeaux (expérience ORPHEE), la seconde le long d'un gradient latitudinal de forêts de hêtres matures dans les Alpes françaises (expérience BIOPROFOR).Les résultats obtenus montrent que les racines de bouleaux et de pins présentaient une distribution verticale similaire et une biomasse souterraine similaire de racines dans les mélanges d'arbres par rapport aux monocultures, contrairement à ma première hypothèse. Cependant, l'attribution plus importante du pin mais pas du bouleau à la croissance des racines dans les horizons du sol supérieur dans des conditions moins limitatives en eau suggère des conditions localement favorables qui peuvent conduire à une compétition asymétrique à la profondeur du sol. De plus, la production et la décomposition des racines fines étaient similaires dans les mélanges et dans les monocultures, en contradiction avec ma deuxième hypothèse. Il est intéressant de noter que les racines de bouleau, mais pas les racines de pin, ont libéré du P pendant leur décomposition, ce qui suggère un rôle important du bouleau dans le cycle du P et pour la nutrition en P des arbres sur ces sols sableux limités en P. Conformément à ma troisième hypothèse, j'ai observé une décomposition plus lente de la litière de feuilles et des racines fines en réponse à une sécheresse estivale prolongée, tout au long du gradient latitudinal dans les Alpes. Cependant, cette décomposition plus lente sous la sécheresse n'a pas été atténuée dans les peuplements forestiers à essences mixtes par rapport aux peuplements à essences uniques. Il est intéressant de noter qu’il y a une libération nette d'azote dans les racines fines en décomposition mais pas dans la litière de feuilles en décomposition, ce qui suggère un rôle distinct des racines fines dans le cycle de l'azote. En conclusion, j'ai constaté que le mélange des espèces d'arbres n'atténue pas les effets négatifs du changement climatique. Cette thèse démontre que la promotion de mélanges peut toujours être bénéfique pour au moins une des espèces d'arbres mélangées, par l'ajout d'espèces, car une espèce d'arbre peut en faciliter la nutrition minérale d’une autre par des flux souterrains de N et de P
The insurance hypothesis predicts that forests with tree species mixtures may resist better to stressful environmental conditions than forests composed of only one tree species. Most of the currently available literature tested this hypothesis for aboveground productivity and its related response variables, but less is known about belowground processes. In my PhD thesis, I studied the drivers of belowground productivity and decomposition across climatic gradients and how they are affected by tree mixtures. I hypothesized that mixing of tree species with contrasting rooting patterns and fine root morphologies, would result in a release of competitive pressure belowground, and translate into higher fine root standing biomass and increased fine root productivity. Moreover, I hypothesized that roots with contrasting chemical and morphological characteristics in mixed stands would decompose faster, which may be particularly important under nutrient-limited conditions. Under water-limiting conditions, such as during extreme summer drought, I hypothesized overall slower decomposition but an attenuating effect of tree mixtures on decomposition due to improved micro-environmental conditions, in particular for leaves, since roots decompose in a more buffered soil environment. To test these hypotheses I examined the variation in tree root functional traits (across- and within-species), and its consequences for fluxes of C, N and P at the ecosystem scale. I addressed three main objectives and associated research questions to quantify the interactive effect of tree mixtures and climate on: 1) vertical root segregation and fine root standing biomass, 2) fine root dynamics and their associated nutrient fluxes and 3) fine root- and leaf litter decomposition. I could benefit from two different field experiments for my work, one with a 10-year-old tree-plantation experiment with birch and pine close to Bordeaux (ORPHEE experiment), the second along a latitudinal gradient of mature beech forests in the French Alps (BIOPROFOR experiment).I observed that roots from the birch and pine tree-plantation showed similar vertical distribution and similar belowground root standing biomass in tree mixtures compared to monocultures, contrary to my first hypothesis. However, the greater allocation of pine but not of birch to root growth within the top soil horizons under less water-limiting conditions suggests locally favourable conditions that may lead to soil depth-specific asymmetric competition. In the same experiment, fine root production and decomposition were similar in mixtures and in monocultures, in contradiction with my second hypothesis. Moreover, I did not observe any interactive effects of tree mixtures with stand density or water availability. Interestingly though, birch roots, but not pine roots released P during root decomposition, which suggests an important role of birch in the P-cycle and for P nutrition of trees on these P-limited sandy soils. In line with my third hypothesis, I observed a slower decomposition of leaf litter and fine roots in response to reinforced and prolonged summer drought, irrespective of the position along the latitudinal gradient in the Alps. However, this slower decomposition under drought was not attenuated in forest stands with mixed tree species compared to single species stands. Compared to leaf litter, fine roots decomposed slower and released less C. Interestingly, I found a net N release in decomposing fine roots but not in decomposing leaf litter, which suggests a distinct role of fine roots in the N cycle. In conclusion, I found that mixing tree species did not attenuate negative effects of climate change. However, this thesis demonstrates that promoting mixtures can still be beneficial for at least one of the admixed tree species, through species addition (i.e., complementing one tree species with another tree species), as one tree species may facilitate another via belowground fluxes of N and P

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Sangha, Kamaljit Kaur, and Kamaljit kaur@jcu edu au. "Evaluation of the effects of tree clearing over time on soil properties, pasture composition and productivity." Central Queensland University. School of Biological and Environmental Sciences, 2003. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20060921.115258.

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Tree clearing is practised for greater beef production and hence monetary gains from grazing systems of central Queensland. The high rates of clearing in the past and even recently (577, 000 ha/yr during 1999-2001) were mainly to develop land for pastures. The sustainability of cleared pasture systems over the long-term is questioned. Three major types of tree communities i.e. Eucalyptus populnea F. Muell., E. melanophloia F. Muell. and Acacia harpophylla F. Muell. ex. Benth. were selected on one property in central Queensland to quantify the impacts of clearing on pasture production and composition, and soil properties. The impacts were measured over time-since-clearing (recent (<5 years), medium (11-13years) and old (>30 years)) in unreplicated cleared pastures in comparison to their replicated uncleared/intact woodland pastures of each tree community. Measures of pasture above-ground biomass production on a single property over time-sinceclearing in cleared systems showed that gains were not sustained over the long-term. The difference in response to clearing between tree communities was evident and important to support the future policy decisions. The impact of clearing on soil properties (physicochemical and biological) was confirmed, and explained the lesser availability of nutrients with time of clearing in cleared pastures. The changes in some soil properties underscored the associated risks and changes in ecosystem functions due to clearing. Less litter was produced at cleared than uncleared pastures, but nutrient release was faster at cleared compared to uncleared systems. The overall effect of clearing in terms of pasture and litter production, and major soil parameters were analysed using multivariate analyses.

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Laliberté, Etienne. "Land-Use Intensification in Grazing Systems: Plant Trait Responses and Feedbacks to Ecosystem Functioning and Resilience." Thesis, University of Canterbury. School of Forestry, 2011. http://hdl.handle.net/10092/5109.

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Land-use change is the single most important global driver of changes in biodiversity. Such changes in biodiversity, in turn, are expected to influence the functioning of ecosystems and their resilience to environmental perturbations and disturbances. It is widely recognised that the use of functional traits and functional diversity is best for understanding the causes and functional consequences of changes in biodiversity, but conceptual development has outpaced empirical applications. This thesis explores these ideas in grazing systems, which are expected to undergo rapid intensification of fertiliser use and grazing pressure to meet the growing global demand for livestock products. First, a flexible framework for measuring different facets of functional diversity is described, and a new multidimensional functional diversity index, called functional dispersion (FDis), is presented. Second, two vegetation sampling methods are compared with regard to their ability to detect changes in vegetation composition. Third, shifts in plant trait distributions following land-use changes are quantified and compared to null models, and a maximum entropy approach is used to quantify the direction and strength of selection on each trait. Fourth, it is shown that these shifts in trait distributions have cascading effects on primary production, litter decomposition, soil respiration, and ultimately soil carbon sequestration. Finally, data from 18 land-use intensity gradients are used to show that land-use intensification reduces functional redundancy and response diversity, two components of biodiversity that are thought to influence ecosystem resilience to future disturbances. This study illustrates (i) the importance of considering species functional differences to understand how plant communities react to changes in soil resource availability and grazing pressure, and (ii) how such changes directly, indirectly, and interactively control ecosystem functioning, as well as (iii) increasing the vulnerability of ecosystems to future disturbances.

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Grugiki, Marilia Alves. "Ciclagem de nutrientes em coberturas florestais no sul do Espírito Santo." Universidade Federal do Espírito Santo, 2011. http://repositorio.ufes.br/handle/10/5801.

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Made available in DSpace on 2016-12-23T13:51:51Z (GMT). No. of bitstreams: 1 Dissertacao de Marilia Alves Grugiki.pdf: 353641 bytes, checksum: fa4c0514512e156b81e2fcfbd041e310 (MD5) Previous issue date: 2011-05-10
Este trabalho teve como objetivo geral avaliar a dinâmica de nutrientes e sua relação com o aporte, decomposição e mineralização da serapilheira nas coberturas florestais de floresta secundária, Sapindus saponaria, Acacia mangium e Hevea brasiliensis na região sul do estado do Espírito Santo. A deposição da serapilheira foi quantificada instalando 3 coletores (50 x 50 cm), em cada cobertura florestal. O material interceptado pelos coletores foi mensalmente coletado durante o período de janeiro a outubro de 2010. Para a quantificação do acúmulo de serapilheira no solo foi utilizado um gabarito de 0,33 x 0,33 m nos meses de novembro/2009, março/2010, junho/2010 e novembro/2010. Tanto no estudo de deposição de serapilheira como no de acúmulo, as amostras de serapilheira coletadas foram levadas para laboratório onde foram secas em estufa e pesadas, sendo em seguida determinados os teores e estoques de Ca, Mg, P e K. A decomposição da serapilheira foi quantificada através de litter bags coletados em cada cobertura florestal. O material remanescente em cada litter bags foi coletado em diferentes períodos de tempo onde foram pesados para obtenção da matéria seca. Para a avaliação da atividade microbiana, procedeu-se a quantificação do CO2 (C mineralizável). Os resultados experimentais mostraram que as coberturas florestais se comportaram de forma diferenciada quanto à deposição e acúmulo de serapilheira, com destaques para a Acacia mangium que, na época seca, proporcionou maior deposição de serapilheira total e para a seringueira, que dentre as coberturas florestais, foi a que apresentou desempenho inferior tanto para a deposição quanto para o acúmulo de serapilheira. Dentre os nutrientes avaliados na serapilheira depositada e acumulada, o teor de fósforo não variou entre as coberturas florestais, o mesmo ocorrendo para o teor de potássio na fração folhas e de magnésio na fração não-folhas da serapilheira depositada. O acúmulo de nutrientes foi mais influenciado pela produção de serapilheira do que pelos teores de nutrientes na serapilheira. A Acacia mangium, juntamente com a floresta secundária, apresentaram, de maneira geral, valores superiores e a seringueira, os menores valores. Quanto à decomposição, os resultados experimentais mostraram que as coberturas florestais se comportaram de forma diferenciada quanto à decomposição e atividade microbiana, com destaques para a Sapindus saponaria que, apresentou maior velocidade de decomposição de serapilheira total e para a seringueira, que dentre as coberturas florestais, foi a que apresentou velocidade de decomposição inferior em relação às outras coberturas. O conteúdo de nutrientes liberados na decomposição da serapilheira apresentou comportamento decrescente ao decorrer dos dias. A cobertura de Sapindus saponaria, apresentou para as duas profundidades, quantidades acumuladas de CO2 superiores em relação às outras coberturas florestais. A cobertura de Acacia mangium apresentou os menores valores de CO2 acumulado. Para este estudo, dentre os parâmetros avaliados, o acúmulo de nutrientes e a produção de serapilheira acumulada e ix depositada mostraram-se como importantes indicadores para avaliação de ciclagem de nutrientes em coberturas florestais
This study aimed to assess the overall nutrient dynamics and their relationship with the input, decomposition and mineralization of litter in the forest canopy of secondary forest, Sapindus saponaria, Acacia mangium and Hevea brasiliensis in the southern state of Espírito Santo. The deposition of litter was measured by installing three collectors (50 x 50 cm) in each forest cover. The material was intercepted by collectors collected monthly during the period from January to October 2010. To quantify the accumulation of litter in the soil was used a template 0.33 x 0.33 m in the months of November/2009, March/2010, November/2010 and June/2010. Both the study of deposition of litter accumulation as in the samples of litter were taken to the laboratory where they were oven dried and weighed, and then determined the levels and stocks of Ca, Mg, P and K. The decomposition of leaf litter was measured using litter bags collected in each forest cover. The remaining material in each litter bags were collected at different periods of time they were weighed to obtain dry matter. For the assessment of microbial activity, proceeded to quantify the CO2 (mineralizable C). The experimental results showed that the forest cover behaved differently regarding the deposition and accumulation of litter, with emphasis on Acacia mangium that, in the dry season, provided greater total litter deposition and rubber, that among the forest canopy, showed the lower performance for both the deposition and to the accumulation of litter. Among the nutrients in litterfall and accumulated phosphorus content did not vary between forest cover, and so on for the potassium content in leaves and magnesium fraction in the fraction of non-leaf litterfall. The accumulation of nutrients was more influenced by litter production than by the nutrient content in the litter. Acacia mangium, together with the secondary forest showed, in general, higher values and rubber, the lowest values. As for the decomposition, the experimental results showed that the forest cover behaved differently in terms of decomposition and microbial activity, with highlights for Sapindus saponaria that had a higher rate of decomposition of total litter and rubber, that among the forest cover, showed the lower rate of decomposition in relation to other coverage. The content of nutrients released in the decomposition of litter produced the downward trend over the day. The coverage of Sapindus saponaria presented for two depths, higher amounts of CO2 accumulated in relation to other forest cover. Coverage of Acacia mangium showed the lowest values accumulated CO2. For this study, among the parameters evaluated, the accumulation of nutrients and the production of litter accumulated and deposited proved as important indicators for assessing nutrient cycling in forest cover

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Sariyildiz, Temel. "Biochemical and environmental controls of litter decomposition." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312079.

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Yin, Na. "Mechanism of Positive, Non-Additive Litter Decomposition." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8564.

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Litter decomposition is a fundamental ecosystem process. It is responsible for nutrient cycling and influences carbon (C) sequestration, and soil physical and chemical properties. In nature, litter is usually heterogeneous and may not decompose the way homogeneous litter does. For example, heterogeneous litter decomposition is frequently non-additive. This makes the rate of nutrient cycling as well as fluxes of C into and out of soil C pools impossible to predict. The most frequently proposed mechanisms for positive, non-additive decomposition include the supply of limiting mineral nutrients, the supply of available C (priming), and the improvement of micro-environmental conditions. However, all three mechanisms are controversial in the sense that no single mechanism accounts for all cases of non-additive decomposition. In mesic ecosystems, both soil microbes and soil fauna are the major causes of decomposition. Microbes decompose litter by producing extracellular enzymes. The comminution of litter by soil animals interacts with microbial activities by increasing substrate surface area. In our study, positive, non-additive decomposition of oat straw when mixed with clover was not due to enhancing microarthropod density in oat straw but associated with significantly increased microbial activity in oat straw. We further investigated the factors that contribute to positive, non-additive decomposition by testing several common hypotheses used to explain non-additive decomposition (increased water content, and the transfer of C and/or nitrogen (N) compounds from clover to oat straw). We also tested a new hypothesis, which is that C, N and other nutrients are simultaneously supplied by clover to stimulate the decomposition of oat straw. Our study indicated that the addition of water to oat straw did not increase oat straw decomposition and adding ammonium chloride only or glucose and ammonium chloride together to oat straw had no significant effect on oat straw decomposition. Glucose addition alone (Low concentration) increased oat straw decomposition but was not sufficient to predict the effect of clover litter. Either the addition of glucose, ammonium chloride and other minerals together to oat straw, or soil was in contact with oat straw and glucose and ammonium chloride were added, oat straw decomposition was stimulated as if clover were present. These results suggest that the limiting resources are some combination of C, N and other mineral nutrients and that soil itself may be a source of limiting nutrients in litter decomposition. In nature, some combination of high quality litter and soil itself may supply resources that stimulate the decomposing organisms’ activity on low quality litter and then the decomposition of low quality litter. Our research provides insight into the dynamics of heterogeneous litter decomposition and will allow us to better model nutrient cycling.

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Almeida, R. de. "Nutrient and litter decomposition in a beechwood ecosystem." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354800.

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Joly, François-Xavier. "Tree diversity and litter decomposition in European forests." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS215.

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Les écosystèmes forestiers jouent un rôle clé en régulant des cycles du carbone (C) et des nutriments et l’érosion en cours de la biodiversité peut affecter ces fonctions écosystémiques. Ces deux dernières décennies, un effort de recherche important a cherché à comprendre comment la biodiversité affecte la productivité primaire. Le processus inverse de minéralisation du C pendant la décomposition de la matière organique est en revanche beaucoup moins étudié. Dans cette thèse, j’ai cherché à démêler les différents mécanismes par lesquels la diversité des arbres et de leurs litières foliaires affecte la décomposition des litières dans les écosystèmes forestiers d’Europe, à travers trois approches.En utilisant un réseau de placettes forestières contenant des gradients de diversité dans six types de forêts à travers l’Europe, j’ai étudié les effets de la diversité des arbres sur la décomposition de la litière via (i) des modifications de l’environnement de décomposition et (ii) les conséquences directes de la diversité des litières foliaires, avec deux expériences en sachets de litière. A travers tous les sites, alors que la richesse spécifique des arbres a eu un effet limité, la fermeture de la canopée a positivement affecté la décomposition par une modification potentielle des conditions microclimatiques. De plus, les traits moyens de qualité physique et chimique de la chute de litière et la dissimilarité de traits entre les litières d’espèces différentes ont influencé les communautés de décomposeurs permettant dans une certaine mesure de prédire la décomposition de substrats standards. Une fois ces effets pris en compte, la qualité des litières en décomposition a eu un impact supplémentaire mais relativement plus faible sur la décomposition. Ces résultats suggèrent que les effets indirects de la diversité des arbres sur la modification des conditions microenvironnementales sont plus importants pour la décomposition que les effets directs de la qualité intrinsèque des litières en décomposition.J’ai ensuite exploré le rôle des composés solubles lessivés à partir de litière d’espèces différentes sur les processus microbiens du sol par une expérience en microcosmes. Les lessivats de litière d’arbres décidus étaient qualitativement et quantitativement différents de ceux des litières de conifères et ont induit une respiration microbienne du sol plus importante. Le mélange de lessivats des différentes espèces a donné lieu à des effets non-additifs sur les processus microbiens du sol, associés à la dissimilarité de stochiométrie des lessivats. Le lessivage étant un processus dominant pendant la phase initiale de décomposition, l’identité et la diversité des lessivats peut contribuer au contrôle du recyclage du C et des nutriments.Par une troisième approche, mon but a été de mieux comprendre les mécanismes qui sous-tendent les forts effets observées des détritivores du sol sur la décomposition des litières et les effets de diversité. J’ai cherché à comprendre si la transformation de litière en fèces par le détritivores Glomeris marginata stimulait les décomposeurs microbiens, et si cette stimulation dépendait de la qualité de la litière ingérée. L’activité microbienne était stimulée pour les fèces issues de litières récalcitrantes, mais pas pour les fèces issus de litières de meilleure qualité initiale. Ainsi, les conséquences de la transformation de litière en fèces de macroarthropodes pour les décomposeurs microbiens dépend de l’espèce de litières et peut contribuer aux effets de diversité des litières.Les données collectées durant cette thèse montre que la diversité fonctionnelle des arbres peut affecter la décomposition des litières à travers plusieurs mécanismes à différentes étapes de la décomposition. Du fait de cette complexité, les conséquences des changements de diversité pour le cycle du C et des nutriments dans les forêts d’Europe peuvent être importantes, mais sont actuellement difficiles à prédire et à généraliser
Forest ecosystems play a key role in regulating the global carbon (C) and nutrient cycles, and the ongoing erosion of biodiversity is susceptible to modify these ecosystem functions. Over the past two decades, a strong research effort was put into the understanding of how changing biodiversity impacts primary productivity. The reverse process of respiratory C loss during organic matter breakdown however, remained much less studied. In this PhD thesis, I aimed at teasing apart the different mechanisms of how tree and associated leaf litter diversity may affect litter decomposition in European forest ecosystems using three distinct approaches.First, using a network of forest plots with tree diversity gradients in six major forest types across Europe, I studied the effects of tree diversity on litter decomposition through (i) modifications of the decomposition environment and (ii) the direct consequences of leaf litter diversity, with two litterbag experiments. Across all sites, while tree species richness had only a limited effect, forest canopy closure affected decomposition positively by potentially improving microclimatic conditions. In addition, mean chemical and physical quality traits of the litterfall, and trait dissimilarity in leaf litter from different species influenced decomposer communities in a way that decomposition of the common substrates was predictable to a reasonable degree. Once these effects were accounted for, the quality of decomposing litter showed an additional, but comparatively small impact. Collectively, these results suggest that the indirect effects of tree diversity on decomposition through microenvironmental controls are more important than the direct effects of the inherent quality of decomposing litter.With a second approach using microcosms under controlled-conditions, I aimed at assessing the role of soluble compounds leached from decomposing litter of different species for microbial-driven soil processes. Leachates from litter of broadleaved deciduous species differed in composition and quantity and induced stronger soil microbial respiration than those from litter of coniferous species. When the species-specific leachates were mixed, I observed non-additive mixing effects on soil microbial processes associated to the dissimilarity in leachate stoichiometry. Since leaching is the dominant process during the initial stage of decomposition, litter leachate identity and diversity may significantly contribute to the control of carbon and nutrient cycling.Finally, in a third approach my goal was to better understand the underlying mechanisms of the observed strong effects of soil detritivores on litter decomposition and diversity effects. I investigated whether the transformation of litter into feces by the detritivore Glomeris marginata stimulated microbial decomposers, and whether this stimulation depended on the quality of the ingested litter. Microbial activity was stimulated in feces derived from recalcitrant litter, but not in feces derived from litter of higher initial quality. In conclusion, the consequences of litter transformation into macroarthropod feces for microbial decomposers is litter species-specific which may further contribute to litter diversity effects.The data collected during my PhD thesis shows that the functional diversity of trees can affect litter decomposition through various mechanisms during different stages of decomposition. As a result of this complexity, the consequences of changes in biodiversity for the carbon and nutrient cycles in European forests can be substantial, but are presently difficult to predict and to generalize

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Magnusson, Rebecca. "Effects of litter quality and latitude on decomposition." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-137763.

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Decomposition of organic material (litter) is an important part of the global carbon cycle. Environmental conditions, litter quality and the microbial community are the main factors affecting decomposition. The decomposition is divided into two phases, one fast initial phase and one slow second phase. The tea bag index (TBI) was used as a standardized method to measure decomposition rate along a latitudinal gradient. A common garden set up and extractions were made to determine the composition of the litter to investigate if climate or litter quality affected the decomposition rate. The result showed that the decomposition rate increased with higher latitude. The litter from higher latitude has more material that is easy to decompose. Natural litter abroad had higher decomposition rate than at home. On the contrary, standard litter at home had higher decomposition rate than abroad. This indicates that litter quality is more important than latitude. Further studies are needed with more sites along the gradient to conclude how climate and litter quality are affecting decomposition.

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Schindler, Markus. "Effects of litter diversity, leaf quality and water chemistry on litter decomposition in streams /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16789.

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Zukswert, Jenna Michelle. "How well do plant functional traits and leaf-litter traits predict rates of litter decomposition?" Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57698.

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Foliar functional traits have been shown to strongly co-vary with each other and with rates of litter decomposition, demonstrating an “after-life effect” of foliar traits on ecosystem processes. Leaf-litter traits are often used to indicate substrate quality in decomposition studies. Chemical traits have been studied more extensively in the context of decomposition than physical traits such as specific leaf area (SLA) and leaf toughness, which impart information on litter structure and decomposer access. I investigated relationships among foliar and litter traits, and between traits and early mass-loss, in 14 plant species native to British Columbia. Both physical and chemical traits were measured in foliage and leaf litter of each species. Foliar traits novel to this kind of study include cuticle thickness and distance to lumen (DTL); novel litter traits include leaching loss and water uptake after 2 and 24 hours. Decomposition, as net proportion of mass lost over time, was measured in litterbags installed in a temperate rain forest at the University of British Columbia Farm in Vancouver. Mass loss was divided into two phases: Phase I from 0 to 3 months, and Phase II from 3 to 12 months. Foliar traits co-varied in ways predicted by the leaf economics spectrum hypothesis, and litter traits similarly co-varied. Trait-based relationships among species differed when using foliar traits and using litter traits, suggesting that the same traits measured in foliar and litter impart different meaning in the context of decomposition. Phase I was best predicted by leaching loss and litter traits, suggesting that leaching dominates Phase I, and Phase II was best predicted by foliar functional traits such as leaf dry matter content and nitrogen that relate to relative mesophyll abundance, suggesting that decomposer activity dominates Phase II. Physical traits predicted mass loss as well or better than chemical traits, and using both types of traits in correlative studies may provide insights into the processes that underlie litter decomposition.
Forestry, Faculty of
Graduate

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Baroudi, Robby Hassan. "Interactive Effects of Litter Quality and Invertebrates on Litter Decomposition Rates Across a Successional Gradient." Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1467656636.

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15

Balcer, Natalie. "Litter decomposition and phosphorus release in Okeechobee isolated wetlands." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0016520.

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Smaill, Simeon John. "The Decomposition of Nothofagus fusca Floral and Bark Litter." Thesis, University of Canterbury. Biological Sciences, 2001. http://hdl.handle.net/10092/1372.

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Nutrient cycles and budgets have been calculated for various ecosystems, but the impact of floral and bark litter decomposition on nutrient cycling has been little investigated. In this study, the characteristics and decomposition of floral and bark litter produced by Nothofagus fusca in the Lewis Pass Reserve, New Zealand, was investigated, using both field and laboratory studies. Nothofagus fusca floral litter production in 1999 was 734 ± 76 kg ha⁻¹. Floral production in 2000 was estimated to be approximately 1% of this mass, the considerable difference being due to mast flowering in 1999. The decay rate constant, k, for floral litter in the field was 0.94 ± 0.01, and mass loss after one year was estimated to be 61%. The input of nitrogen to the litter layer in Nothofagus fusca floral litter was 12 ± 1 kg ha⁻¹, and it was estimated that 65% of this nitrogen was released from the floral litter in the one year. Phosphorous input to the litter layer through Nothofagus fusca floral litter in 1999 was 0.8 ± 0.1 kg ha⁻¹, of which 69% was released in one year. It was estimated that in 1999 nitrogen and phosphorous inputs to the litter layer through Nothofagus fusca floral litter were 117% and 73% respectively of that through foliar litter. Four types of Nothofagus fusca bark were identified and further differences between bark types were confirmed by chemical analysis. Inner bark contained less nitrogen than outer bark, and was slower to decompose in microcosms, contradicting the findings of other research. Annual nitrogen and phosphorous inputs through the production of all types of Nothofagus fusca bark litter was estimated to be 1.0 kg ha⁻¹ and 0.2 kg ha⁻¹ respectively, although confidence in these values was low. Significant proportions of the nitrogen and phosphorous content in bark were water soluble. Field and laboratory experiments indicated net nitrogen immobilisation occurred in all bark litter types after one year in the field, while net release of phosphorous occurred after one year.

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Lidman, Johan. "Decomposition of leaf litter in headwater streams. : Effects of changes in the environment and contribution of microbial and shredder activity on litter decomposition." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-105488.

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Headwaters, which are the most common stream order in the landscape, are mostly dependent on energy produced in the terrestrial system, largely consisting of leaf litter from riparian vegetation. The aim of this study was to investigate the decomposition in headwaters of leaf litter from three native (alder, birch, spruce) and one non-native (lodgepole pine) species and how decomposition responds to changes in the environment. Further, microbial and shredder influences on leaf-litter decomposition and aquatic decomposer ability to adapt to non-native species was investigated. By using field-data from this study, calculations were made to assess if microbes and shredders are resource limited. Litterbags were placed in 20 headwater streams in northern Sweden that varied in water chemistry, stream physical characteristics and riparian vegetation. The results revealed that species litter decomposition of different plant species was affected differently by changes in environmental variables. Alder and birch decomposition were positively associated, whereas lodgepole pine deviated from the other species in decomposition and its relationship with important environmental variables, indicating that the ability of the boreal aquatic systems to decompose litter differs between introduced and native species. When including macroinvertebrates, shredder fragmentation generally increased decomposition, but was not significant for all sites. Resource availability for microbes and shredders was controlled by litter input, and no risk of resource limitations was evident during the study period. These findings highlight a complexity of the decomposition process that needs to be considered when predicting changes due to human activities.

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Dale, Sarah Elizabeth. "Leaf litter decomposition in tropical forests : disentangling leaf litter quality, soil nutrients, climate and microbial decomposers." Thesis, Lancaster University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.658223.

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Leaf litter decomposition in lowland tropical forests represents a significant flux of carbon (C) to the atmosphere, and is controlled by both extrinsic site conditions and intrinsic litter traits. However, there is a gap in the understanding about the relative importance of these two factors, and of the role of interactions between them. Global change drivers, such as mean annual precipitation (MAP) change and soil nitrogen (N) fertilisation by deposition, could affect both pathways simultaneously. In order to predict the response of the global C cycle to future change, a further understanding of such interactions is required, and is the focus of this thesis. Using a range of experimental factorial studies, in the field and laboratory, in mature tropical forests in Panama, the relative and interactive effects on decomposition of MAP, soil N and phosphorus (P) availability, litter species identity, and litter N and P status, were determined. Leaf litter species identity was a significant predictor of decomposition across the landscape, whilst soil C:N ratio was more important than MAP. Within species, elevated P concentration and decreased N:P ratio in litter was associated with decreased C mineralisation. Increased soil N availability altered microbial community composition, which increased decomposition of some leaf litter types. The results highlight litter traits as an important driver of decomposition via species identify and intra-species leaf litter chemistry. Also, the implications of decomposer activity and composition for decomposition will depend on litter traits. This thesis contributes valuable research evidence to augment current understanding of the importance of litter traits, and their interactions with decomposers, as a pathway through which global change drivers could affect the C cycle in tropical forests.

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梁慶祥 and Hing-cheung Leung. "Aspects of leaf litter decomposition in Kandelia candel (L.) Druce." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1986. http://hub.hku.hk/bib/B31207728.

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20

Osono, Takashi. "Fungal decomposition of leaf litter in a cool temperate forest." Kyoto University, 2002. http://hdl.handle.net/2433/78146.

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Leung, Hing-cheung. "Aspects of leaf litter decomposition in Kandelia candel (L.) Druce /." [Hong Kong : University of Hong Kong], 1986. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12326082.

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22

Evans, Alison. "The impact of selective beech (Nothofagus spp.) harvest on litter-dwelling invertebrates and the process of litter decomposition." Lincoln University, 1999. http://hdl.handle.net/10182/1717.

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Minimising the potential impact of forest management requires an understanding of the key elements that maintain forest diversity and its role in ecological processes. Invertebrates are the most diverse of all biota and play important roles in maintaining forest processes. However, little is known about invertebrates in New Zealand's beech forests or the degree to which selective beech harvest might impact on their diversity and ability to carry out ecosystem processes. Studying ecosystem responses to disturbance is considered vital for understanding how ecosystems are maintained. One of the main objectives of this research was to assess whether litter-dwelling invertebrates were susceptible to the impacts of selective harvest and, if so, whether they could be used as indicators of forest health. Changes in invertebrate diversity could have important implications for nutrient cycling and primary production in forests. Litter-dwelling invertebrates contribute to the process of decomposition by increasing the surface area of the leaves, mixing soil organic matter and by infecting leaf particles with soil microbes. This investigation into the function of invertebrates in beech forest was carried out in the context of ecological theories which relate diversity to ecosystem stability and resilience. A replicated study was established in Maruia State Forest (South Island, New Zealand) to assess the potential biotic and abiotic impacts of sustainable beech harvest. Litter-dwelling invertebrates and environmental factors were monitored during 1997, before harvest, to determine how much variability there was between study sites. Specifically, litter pH, light intensity, litter fall, litter temperature, moisture as well as invertebrate abundance and diversity were compared before and after selective harvest. On 17 January 1998, two to three trees were selectively harvested from three of the nine study sites. On 15 February 1998 a similar number of trees were winched over or felled manually to create artificial windthrow sites. The remaining three undisturbed sites were used as controls. Invertebrates belonging to the detritivore guild were assessed from litter samples and a series of litter-bags containing pre-weighed leaf litter which were placed in each of the sites to assess rates of litter decomposition. Millipedes (Diplopoda: Polyzoniidae, Schedotrigonidae, Dalodesmidae, Habrodesmidae, Sphaerotheridae), earthworms (Oligochaeta: Annelida), tipulid larvae (Diptera: Tipulidae), weevils (Coleoptera: Curculionidae), moth larvae (Lepidoptera: Oecophoridae, Tortricidae and Psychidae), slaters (Isopoda: Styloniscidae), Oribatid mites (Acarina: Cryptostigmata) and landhoppers (Crustacea: Amphipoda) were extracted from the litter-bags and their abundance and diversity was compared between the three treatments. Weight loss from the litter-bags and the carbon and nitrogen content of litter were used to measure the rate of decomposition in each treatment. An additional study investigated whether exclusion of invertebrates from leaf litter resulted in reduced rates of decomposition. The results indicated that there was an increase in light intensity and a small increase in temperature following selective harvest and artificial windthrow. There was no significant difference in litter moisture or the amount of litter fall between the treatments. Invertebrate abundances were significantly affected by season but did not appear to be affected by selective harvest or artificial windthrow. The diversity of invertebrates remained relatively constant throughout the year, as did the rate of decomposition. When invertebrates were excluded from the leaf litter there was no consequential effect on the rate of litter decomposition. This suggests that there may be compensatory mechanisms taking place between the trophic levels of the food web to maintain processes and that direct links between invertebrates and decomposition are relatively weak. In conclusion, it appears that the effects of selective beech harvest on forest-floor processes were minimal and are comparable to those created by natural windthrow disturbance. It also appears that macroclimatic effects such as seasonal climatic effects have a large effect on forest biota. As none of the invertebrates studied appeared to be detrimentally affected by selective harvest and as there was no direct link demonstrated with decomposition, it was considered inappropriate to advocate the use of this group of invertebrates as indicators of sustainable forest management. The results from this study provide information which may help inform decisions on the future management of diversity in beech forest ecosystems.

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23

Nason, Mark A. "Decomposition of tree leaf litter and formation of soil organic matter." Thesis, Bangor University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409217.

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24

Mohammed, Askia Musah. "Biomass, carbon, nutrient stocks and litter decomposition in Ghanain cocoa ecosystems." Thesis, University of Reading, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625496.

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This study recognised the quantification of biomass, C and nutrient stocks in cocoa systems of Ghana as an important step to producing a sustainable and carbon-friendly cocoa sector. Eight farms in Ghana were selected for sampling cocoa stands on the basis of three variables: region (Eastern region (ER), Western region (WR)), shade management (shaded, un shaded) and stand age «15, >15 years). All biometric data were collected within a plot area of 2700 m2 in each farm. Also two experiments, a l20-day dry matter loss and a l30-day carbon emission from litter decomposition and organic matter mineralization, were conducted concurrently. In these, single species leaf litters: cocoa (as in unshaded cocoa system), Newbouldia laevis (dominant shade tree in Eastern region) and Persea americana (dominant shade tree in Western region) and I: I mixed species leaf litters (mimicking shaded systems: cocoa + Newbouldia laevis and cocoa + Persea americana) were incubated to determine and predict the litter decomposition and nutrient dynamics in cocoa systems with or without the shade trees. Allometric equations were developed to estimate the biomass of live cocoa tree components (R2 = 0.79 - 0.95). Biomass of non-cocoa trees was estimated using an existing allometric equation developed by the Food and Agricultural Organization. In addition, the Water, Nutrient and Light Capture in Agroforestry Systems (WaNuLCAS) model was tested on hypothetical cocoa systems to assess its suitability to simulate biomass, C and nutrient stocks in the systems over time. Total ecosystem biomass ranged from 48.1 ± 6.5 to 101.6 ± 12.6 Mg I ha. The unshaded system had the lowest biomass production. Biomass production was higher in the Eastern than Western region and larger in > 15 years stands than < 15 years stands. While the C stock in biomass from shaded systems was twice that in unshaded systems, there was no significant difference in total ecosystem C stocks (biomass C + soil C to 60 cm depth) between the two systems due to a larger soil carbon stock in the latter.

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25

Dray, Matthew William. "Effects of multiple environmental stressors on litter chemical composition and decomposition." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/68365/.

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Tree litter is a key basal resource in temperate deciduous woodlands and streams that drain them. Litter decomposition promotes carbon and nutrient cycling, fueling woodland food webs. Research to date has not thoroughly explored how ongoing environmental changes affect this process. This study used microcosm and field experiments to investigate how multiple stressors (urban pollution, elevated atmospheric CO2 and stream acidification) affected litter chemical composition, invertebrate consumption, and terrestrial and aquatic mass loss. Leaf litter chemical composition differed between ambient- and elevated-CO2 litters, and between rural and urban litters, but the direction of these responses was complex and differed between experiments. In microcosms, leaf litter consumption by terrestrial and aquatic invertebrate detritivores was species-specific. After exposure to a woodland floor or headwater streams, urban litter broke down faster than rural litter, while CO2 treatment did little to influence mass loss. The abundance, richness and diversity of terrestrial and aquatic invertebrates associated with leaf litter generally declined from 28 to 112 days in the field. Taxon richness and diversity were generally higher in elevated- than ambient-CO2 leaf litter through time, while urban leaf litter had greater diversity than rural litter after 112 days only. Abundance was greater in the circumneutral than the acid stream. Aside from leaf litter, small woody debris was also affected by CO2 treatment: elevated-CO2 twigs had a greater concentration of nitrogen and lignin, and broke down faster than ambient-CO2 twigs on a woodland floor and in headwater streams. This work highlights the complexity of invertebrate- and ecosystem-scale responses to the effects of multiple environmental stressors, with implications for nutrient cycling and food webs. Urban pollution may have a greater influence on litter chemical composition than CO2 treatment, while effects of growth condition may be more important than stream acidity in influencing decay and invertebrate communities.

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26

Giai, Carla. "Fire, Exotic Earthworms and Plant Litter Decomposition in the Landscape Context." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1236626931.

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Suzuki, Yoriko. "The effects of millipedes (Harpaphe haydeniana) on microbial decomposition of leaf litter." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/41623.

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Most estimates of litter decomposition rates do not account well for the effects of soil macrofauna, and so are suspect in ecosystems in which litter-transforming soil fauna are abundant. In coastal rainforests, millipedes consume substantial amounts of leaf litter, most of which is egested as faecal pellets. Little is known about the fate of this material, which hinders estimation of realistic rates of litter decomposition in these ecosystems. In this study, I assess the influence of feeding by the millipede (Harpaphe haydeniana) on decomposition of leaf litter by comparing rates of CO₂ release during laboratory incubation from leaf litter which has been ingested by millipedes and transformed into faecal pellets with that from litter which has not been ingested by millipedes. Changes in litter microbial communities as a consequence of millipede ingestion are assessed by comparing the PLFA profiles of faeces and uningested litter during incubation. Rates of CO₂ release from faeces and litter were similar. CO₂ release was higher in maple litter than Douglas-fir litter, and this difference persisted in the faeces from litter that millipedes fed on. Differences in bacterial abundance between litter types were also retained during millipede gut passage. Grinding of litter increased CO₂ release, as did grinding of faeces, indicating that structure of litter and millipedes’ faecal pellets may restrict microbial access and thus decrease the decomposition rates. Microbial activity and abundance did not differ between leaf litter and faeces incubated alone vs together.

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28

Cotrufo, Maria Francesca. "Effects of enriched atmospheric concentration of carbon dioxide on tree litter decomposition." Thesis, Lancaster University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282385.

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29

Levi, Eva Marie, and Eva Marie Levi. "Foliar and Woody Litter Decomposition in a Shrub-Invaded Sonoran Desert Grassland." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/623065.

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Decomposition of organic matter is a critical component in global biogeochemical cycling. While decomposition rates have been robustly predicted for mesic systems, modeling decomposition dynamics in drylands has proven to be problematic, reflecting a need to account for processes that may be unique to dryland systems: low and spatially variable vegetation cover, high rates of soil movement, and high levels of radiant energy exposure at the soil surface. Recent empirical evidence suggests that the discrepancies between measured and predicted decomposition rates in drylands may be due to the greater influence of abiotic drivers, such as soil-litter mixing (SLM) and solar radiation, on plant litter decomposition relative to more mesic systems. UV-driven photodegradation may dominate until SLM reaches a threshold, at which point litter is shielded from radiation and microbial processes become predominant. The overarching goal of this dissertation was to examine the influence of SLM and solar radiation on decomposition of foliar and woody plant litter in a dryland ecosystem undergoing woody plant encroachment. A series of four complimentary experiments sought to quantify the effects of these abiotic drivers on decomposition in relation to variables such as vegetation patch type (e.g., beneath a shrub canopy, in a grass patch, on bare ground), radiant energy regime (e.g., full sun vs. shade), geomorphic surface (e.g., sandy, Holocene-age vs. clay-rich, Pleistocene-age soils), seasonality of litter fall (e.g., summer vs. winter), and litter quality (e.g., grass, shrub leaf, woody). Results indicate that interactions between SLM and photodegradation are complex and mediated by variations in ground cover which influence the local radiant energy environment and the movement of soil across the landscape by wind and water. Decomposition rates were significantly influenced by SLM, UV radiation, radiant energy regime, vegetation structure, and initial litter quality. While these results confirmed the importance of SLM and photodegradation as dryland decomposition drivers, they also reinforced the need for additional research to further clarify the relative importance of these processes under field conditions, particularly the interplay between UV radiation and SLM and their relative influence on biotic and abiotic decomposition processes. Given the changes in climate and vegetation projected for drylands, it is critical to further elucidate the influence of these processes on dryland biogeochemical cycling, as their effects may be magnified or dampened under future conditions. A deeper understanding of the processes driving biogeochemical cycling that may be unique to systems undergoing shifts in plant lifeform composition will allow us to better account for the fate of carbon in these globally important ecosystems.

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30

Kirkwood, Donovan. "An experimental test of the importance of litter and soil type in the decomposition of five fynbos biome litter types." Thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/26050.

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31

Neatrour, Matthew Aaron. "The Role of Floods in Particulate Organic Matter Dynamics of a Southern Appalachian River/Floodplain Ecosystem." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34913.

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I investigated the role of a flood in particulate organic matter (POM) dynamics of the Little Tennessee river/floodplain ecosystem in western North Carolina, USA. I measured litter inputs, leaf breakdown, floodplain litter, and aboveground herbaceous net primary production at 12 sites. Annual litter inputs (274-625 g m-2 y-1) were typical of a temperate deciduous forest, but lower than other floodplain forests in the eastern United States. Mean aboveground herbaceous net primary production ranged from 61-439 g m-2 y-1 and leaf breakdown rates of 4 tree species ranged from 0.001-0.010 d-1. Following a flood on 8 January 1998, sites were separated into three inundation classes: inundated, partially-inundated, and non-inundated. Sites inundated by a January flood had significantly less forest floor leaf litter and coarse woody debris after the flood. There was no significant change at the partially-inundated or non-inundated sites. In addition, there was no significant difference in herbaceous material between pre- and post-flood collections for any inundation classes. Litter input, leaf breakdown, and floodplain litter standing crop data suggest that flood entrainment of POM from the floodplain of Little Tennessee River is a source of POM to the active channel. The impact of floods on the floodplain POM dynamics, however, is highly dependent on the time of year and magnitude of the flood, and on the structure of floodplain tree assemblages, which is strongly influenced by anthropogenic land use. Compared to direct litterfall and instream primary production, the floodplain may be a small annual source of POM for the river.
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32

Lukumbuzya, T. K. (Tadde Kahana). "Effects of base cation fertilization on litter decomposition in a sugar maple forest." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68207.

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Sugar maple foliage litters from fertilized and unfertilized plots on a base-poor site and from a naturally base-rich site were incubated in litterbags of 1 and 3 mm mesh on fertilized and unfertilized plots at the base-poor site. Mass loss of unfertilized litter was slower in fertilized than unfertilized plots, suggesting a negative effect of fertilization on decomposers. Mass loss of fertilized litter was faster than unfertilized litter in the same plots, indicating that changes in litter quality due to fertilization enhanced microbial decomposition. Mass loss was higher in large mesh than in small mesh size bags, suggesting that larger soil fauna played a significant role in litter decomposition.
Potassium appeared to be rapidly leached, whereas Ca and Mg were released at rates more closely related to litter mass loss. Nitrogen was mineralized from N-rich Arboretum litter only; all other litters immobilized N. Release of Ca and Mg was reduced significantly on fertilized plots. Large soil fauna enhanced Ca release, while they delayed N-mineralization in Arboretum litter.

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Wookey, Philip Andrew. "Effects of dry deposited sulphur dioxide on the decomposition of forest leaf litter." Thesis, Lancaster University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328496.

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34

Thoman, Heather Marie. "A Critical Temperature Threshold for Early Leaf Litter Decomposition and Microbial Enzyme Activity." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1399571419.

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35

Van, der Ham Ilana. "The effect of inorganic fertilizer application on compost and crop litter decomposition dynamics in sandy soil." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97109.

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Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Inorganic fertilizer applications are common practice in commercial agriculture, yet not much is known regarding their interaction with organic matter and soil biota. Much research has been done on the effect of inorganic N on forest litter decomposition, yet very little research has focused on the effect of inorganic fertilizers on crop litters and, to our knowledge, none on composted organic matter. Furthermore none of the research has been done in South Africa. The main aim of this research project was to determine the effect of inorganic fertilizer applications on the decomposition of selected organic matter sources commonly used in South African agriculture and forestry. Two decomposition studies were conducted over a 3-month period, one on composts and the other on plant litters, using a local, sandy soil. In the first experiment a lower quality compost, compost A (C:N ratio, 17.67), and higher quality compost, compost B (C:N ratio, 4.92) was treated with three commercially used fertilizer treatments. Two were typical blends used for vegetable (tomato and cabbage) production: tomato fertilizer (10:2:15) (100 kg N, 20 kg P, 150 kg K per ha) and cabbage fertilizer (5:2:4) (250 kg N, 100 kg P, 200 kg K per ha). The third fertilizer blend, an equivalent mass application of N and P applied at 150 kg of each element per ha, is more commonly used in pastures. In the second experiment, five commonly encountered crop and forestry litters, namely kikuyu grass, lucerne residues, pine needles, sugar cane trash and wheat straw, were selected to represent the labile organic matter sources. The litters were treated with the tomato and cabbage fertilizer applications rates. Both decomposition experiments were conducted under ambient laboratory conditions at field water capacity. Decomposition rates were monitored by determining CO2 emissions, DOC production, β-glucosidase and polyphenol oxidase activity (PPO). At the start and end of decomposition study, loss on ignition was performed to assess the total loss of OM. Based on the results obtained from these two experiments, it was concluded that the addition of high N containing inorganic fertilizers enhanced the decomposition of both composted and labile organic matter. For both compost and plant litters, DOC production was greatly enhanced with the addition of inorganic fertilizers regardless of the organic matter quality. The conclusion can be made that inherent N in organic matter played a role in the response of decomposition to inorganic fertilizer application with organic matter low in inherent N showing greater responses in decomposition changes. For labile organic matter polyphenol and cellulose content also played a role in the responses observed from inorganic fertilizer applications.
AFRIKAANSE OPSOMMING: Anorganiese kunsmis toedieningss is algemene praktyk in die kommersiële landbou sektor,maar nog min is bekend oor hul interaksie met organiese materiaal en grond biota. Baie navorsing is reeds oor die uitwerking van anorganiese N op woud en plantasiereste se ontbinding gedoen. Baie min navorsing het gefokus op die uitwerking van anorganiese kunsmis op die gewasreste en tot ons kennis, is daar geen navorsing gedoen op die invloed van anorganiese kunsmis op gekomposteer organiese material nie. Verder is geeneen van die navorsing studies is in Suid-Afrika gedoen nie. Die hoofdoel van hierdie navorsingsprojek was om die effek van anorganiese kunsmis toedienings op die ontbinding van geselekteerde organiese materiaal bronne, wat algemeen gebruik word in die Suid-Afrikaanse landbou en bosbou, te bepaal. Twee ontbinding studies is gedoen oor 'n 3-maande-tydperk, een op kompos en die ander op die plantreste, met die gebruik van 'n plaaslike, sanderige grond. In die eerste eksperiment is ‘n laer gehalte kompos, kompos A (C: N verhouding, 17.67), en 'n hoër gehalte kompos, kompos B (C: N verhouding, 4.92) met drie kommersieel anorganiese bemesting behandelings behandel. Twee was tipiese versnitte gebruik vir die groente (tamatie en kool) produksie: tamatie kunsmis (10: 2:15) (100 kg N, 20 kg P, 150 kg K per ha) en kool kunsmis (5: 2: 4) (250 kg N, 100 kg P, 200 kg K per ha). Die derde kunsmis versnit was 'n ekwivalente massa toepassing van N en P van 150 kg van elke element per ha, wat meer algemeen gebruik word in weiding. In die tweede eksperiment was vyf algemeen gewas en bosbou reste, naamlik kikoejoegras, lusern reste, dennenaalde, suikerriet reste en koring strooi, gekies om die labiele organiese materiaal bronne te verteenwoordig. Die reste is met die tamatie en kool kunsmis toedienings behandel. Beide ontbinding eksperimente is uitgevoer onder normale laboratorium toestande by veldwaterkapasiteit. Ontbinding tempo is deur die bepaling van die CO2-vrystellings, opgelosde organiese koolstof (OOK) produksie, β-glukosidase en polifenol oksidase aktiwiteit (PPO) gemonitor. Aan die begin en einde van ontbinding studie, is verlies op ontbranding uitgevoer om die totale verlies van OM te evalueer. Gebaseer op die resultate van hierdie twee eksperimente, was die gevolgtrekking dat die toevoeging van hoë N bevattende anorganiese bemestingstowwe die ontbinding van beide komposte en plant reste verhoog. Vir beide kompos en plantreste word OOK produksie verhoog met die toevoeging van anorganiese bemesting, ongeag van die organiese materiaal gehalte. Die gevolgtrekking kan gemaak word dat die inherente N in organiese materiaal 'n rol gespeel het in die reaksie van ontbinding op anorganiese bemesting toedienings met die grootste reaksie in organiese material laag in inherente N. Vir labiele organiese material het polifenol en sellulose inhoud ook 'n rol gespeel in die reaksie waargeneeming op anorganiese bemesting.

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36

Swarts, Derek Juan. "Soil community structure and litter decomposition under irrigated Eucalyptus Globulus in South Western Australia." Connect to thesis, 2006. http://portal.ecu.edu.au/adt-public/adt-ECU2006.0051.html.

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37

Schmidt, John Michael. "Litter Decomposition in Created and Adjacent Forested Wetlands of the Coastal Plain of Virginia." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/43580.

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Litter decomposition is a poorly understood function of constructed and natural forested wetlands. This study compared rates of litter mass loss, changes in litter morphology, and associated macroinvertebrate populations in constructed and natural non-tidal wetlands. Two sets of wetlands (constructed vs. natural) were studied in eastern Virginia; a 9 year-old riparian set near Fort Lee, (FL), and a 2 year-old wet flat set in Charles City County, (CC). Mixed deciduous forest litter collected from the FL natural wetland decayed more rapidly in the created wetlands than the adjacent forested wetlands. Mixed emergent marsh litter collected from the FL created wetland exhibited a similar relationship, although marsh litter decomposed slower than forest litter. Litter area and weight loss followed a similar pattern, although area loss lagged behind weight loss, consistent with an initial leaching phase of decomposition. Both the FL and CC created wetlands exhibited faster litter decomposition than their adjacent forested wetland, however, the FL created wetland had a lower weight:area ratio and higher detritivore abundance than the adjacent forested wetland, while the reverse was true for the CC wetland pair. These relationships suggest macroinvertebrates played an important role in decomposition in the FL created wetland, while other factors were more significant at CC. Faster decomposition in the created wetlands may be of concern for long-term soil organic matter accumulation, or conversely, may indicate quick recovery of the litter decomposition function. Overall, these findings point out the difficulties involved in using certain functional indicators to compare very young and mature systems.
Master of Science

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Herman, John E. "Linking Microbial Community Dynamics to Litter and Soil Chemistry: Understanding the Mechanisms of Decomposition." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1278500390.

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Esquivel, Sheik M. Jimena. "Plant traits and litter decomposition of tree species naturally regenerating in Central America pasturelands." Thesis, Bangor University, 2013. https://research.bangor.ac.uk/portal/en/theses/plant-traits-and-litter-decomposition-of-tree-species-naturally-regenerating-in-central-america-pasturelands(0fd2446f-b38f-45b9-b2bf-d60fd4467b63).html.

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40

Swarts, Derek J. "Soil community structure and litter decomposition under irrigated Eucalyptus Globulus in South Western Australia." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2006. https://ro.ecu.edu.au/theses/100.

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Plantations provide a range of benefits, including the potential to ameliorate salinity and soil erosion, enhance biodiversity, and provide timber and wood chips. They are increasingly important because of their role in carbon sequestration (Adolphson, 2000; Anonymous, 2005; Jones et al. , 2005; Kozlowski, 2002; Paul and Polglase, 2004). Recent research has highlighted the connection between plantation health and soil fertility (Johnston and Crossley Jr, 2002). Within an Australian context there is little published data on the composition of the soil and litter fauna and their contribution to litter decomposition under plantation systems (Adolphson, 2000). The Albany Effluent Irrigated Tree Farm provided an opportunity to research plantation (Eucalyptus globulus ) soil flora and fauna communities, rates of litter decomposition and to describe the impact of irrigation (both mains-water and effluent) on these communities.

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Hetherington, Sarah Louise. "The responses of soil processes at upland boundaries and their role in ecosystem dynamics." Thesis, University of Essex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302562.

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42

Skene, Trudi Marie. "The influence of inorganic matrices on the decomposition of organic materials." Title page, contents and summary only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phs6271.pdf.

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Bibliography: leaves 134-148. The objectives of this study are to determine if and how inorganic matrices influence organic matter decomposition with particular emphasis on the biochemical changes which occur as decomposition progresses. The influence of inorganic matrices (sand, sand + kaolin and loamy sand) on the decomposition of straw and Eucalyptus litter during incubations was followed by various chemical and spectroscopic methods to aid in the understanding of the mechanism of physical protection of organic matter in soils.

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43

Coufal, Craig Daniel. "Quantification of litter production and the fate of nitrogen in commercial broiler production systems." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2626.

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The environmental impacts of broiler production have recently gained considerable public attention due to concerns regarding the amount of ammonia (NH3) released into the atmosphere from poultry facilities. Sound scientific data are needed to accurately estimate the production of manure waste products and gaseous emissions. This research project was undertaken to quantify nitrogen (N) loss through air emissions from a broiler grow-out facility over 18 consecutive flocks using the mass balance method. Measurement of litter and caked litter (cake) mass at the end of each flock allowed for the calculation of litter and cake production rates for broilers reared on recycled rice hull litter. Nutrient (nitrogen, phosphorus, and potassium) content of all litter materials was also measured. Broilers were reared in a research facility under simulated commercial conditions. All input materials (birds, feed, and litter) used in this study were obtained directly from a commercial broiler integrator to assure applicability to the broiler industry. The litter management technique of ??top-dressing?? was also investigated to determine its effects on N emissions and litter and cake production rates. Nitrogen emissions, litter and cake production rates, and nutrient density of litter materials were found to vary significantly between flocks reared at different times of the year. Nitrogen emissions were significantly greater for summer flocks than winter flocks. Average N loss over all 18 flocks was 11.07 g N/kg of marketed broiler (g N/kg). Nitrogen partitioning as a percentage of inputs averaged 15.29, 6.84, 55.52, 1.27, and 21.08% for litter, caked litter, broiler carcasses, mortalities and nitrogen loss, respectively, over all 18 flocks. Litter and cake production was lower in the summer compared to winter. Average litter, cake, and all litter (litter + cake) production was 153.3, 74.8, and 228.2 g of dry litter material/kg of marketed broiler. Litter and cake phosphorus and potassium content was elevated during summer flocks, while litter material N content decreased in summer flocks. Therefore, season of the year is an important factor that scientists and broiler producers must take into account when performing measurements and calculations, sampling litter materials and air emissions, and developing nutrient management plans.

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Montemarano, Justin Joseph. "Biotic controls of decomposition dynamics in aquatic systems." Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1370539247.

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Bell, Michael Christopher. "The direct and indirect role of climate in regulating litter decomposition processes in blanket peatlands." Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/73486/.

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Peatlands are an important component of the global carbon (C) cycle, accounting for around 20-30 % of global soil C. They accumulate C as long as the losses (through decomposition) are less than the inputs (through above- belowground litter production). In the UK, rain-fed blanket peatlands are the dominant peatland type, relying on a large precipitation excess over evaporation to create the waterlogged conditions that promote peat accumulation. This potentially makes them highly sensitive to the effects of climate change. Understanding the sensitivity of blanket peat litter decomposition to climate change is, therefore, of great importance to understand future stability of C stocks, particularly to parameterise dynamic peatland C models. However, to date, there have been relatively few studies of decomposition on blanket peat. In this thesis, a number of experiments primarily focussed on decomposition were carried out with realistic climate treatments simulated in the laboratory and across gradients analogous to near future climate change. The intention was to allow a more accurate quantification of the effects of climate change on peat decomposition processes under ‘realistic’ climatic treatments. By using field sites that lie at the margin of the climatic envelope associated with blanket peatlands, in the south west (SW) of England, we also sought to get a better understanding of how rates of decomposition in other, more northern, blanket peatlands in the UK might be affected by future climate change. A clear finding was that the rate of decomposition varied significantly between different litter types, suggesting an important indirect effect of climate change – shifting vegetation communities – could be one of the most important factors affecting future C accumulation. Despite clear differences in peat temperature between the sites along the altitudinal gradient (330 – 520 m asl), this did not translate into a corresponding reduction in decomposition rate. It appears that other environmental factors (such as increased nitrogen deposition) could be counteracting the effect of decreased temperature, or that peatland litter decomposition rates are relatively insensitive to temperature. That the decomposition did not decrease with altitude also suggests that productivity could be more important in controlling net peat accumulation, potentially increasing with altitude in response to factors such as N deposition. This could have ramifications for the future C balance of these systems, but further work is needed to disentangle the effects of climate from other environmental drivers and determine the balance between productivity and decomposition.

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Hesselschwerdt, John [Verfasser]. "Impacts of invasive amphipods on the local benthic fauna and leaf litter decomposition / John Hesselschwerdt." Konstanz : Bibliothek der Universität Konstanz, 2009. http://d-nb.info/1020366109/34.

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Cuke, Melissa Erin. "Losses of rare forest invertebrates and divergent rates of litter decomposition under different land uses." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/41564.

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Habitat destruction and fragmentation are dominant disturbances in tropical landscapes, but consequences of these changes for invertebrates and ecosystem functioning are poorly described and explained. In northwestern Costa Rica I used pitfall sampling and litter bag experiments to investigate consequences of two land-use changes (forest conversion to orange groves and forest fragmentation) for litter invertebrates and decomposition. I infer effects of forest conversion and fragmentation based on comparisons of intact forest with orange groves and forest fragments, respectively. Invertebrate diversity differed among habitat types. Invertebrate family richness and evenness in orange groves were 24% and 56% lower, respectively, relative to intact forest. Beta diversity (dissimilarity in invertebrate composition) among orange groves was high, likely due to variation in microclimate with grove age and/or management regime. Forest patch diversity was similar to that of intact forest, and composition was marginally more dissimilar between forest patches than between intact forest sites. Consistency in local richness between intact and fragmented forest was largely attributed to a suite of disturbance-adapted taxa detected exclusively in forest patches. Approximately 11% of the families that were naturally common in intact forest were rare or range-limited in forest fragments. These results emphasize the need for large forest reserves to prevent considerable losses of intact forest fauna. Losses of intact forest invertebrates in both orange groves and forest patches were explained by habitat modification (increases in litter temperature) and were more likely for families that are naturally rarer. Forest conversion and fragmentation had divergent effects on litter decomposition. During the wet season, decomposition was 9% faster in orange groves relative to forest. This pattern was explained by higher temperatures and lower litter cover in orange groves; I discuss both indirect and direct microenvironment mechanisms. In contrast, dry season decomposition rates were 7% slower in forest fragments than those in intact forest. Fragmentation effects on decomposition were explained by the action of shredder and/or saprophagous macroinvertebrates, which enhanced decomposition rates in intact forest but not in forest patches. The seasonal aspect of these results emphasizes the importance of accounting for intra-annual variation when assessing disturbance effects in natural systems.

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Rossi, Florent. "Leaf Litter decomposition in streams subjected to global change : the role of heterotrophic microbial communities." Thesis, Université Clermont Auvergne‎ (2017-2020), 2018. http://www.theses.fr/2018CLFAC101.

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L’activité humaine, au travers de l’industrie, l’urbanisation ou encore l’agriculture, a conduit à la production et au relargage d’une grande quantité de produits chimiques (dont les xénobiotiques) dans la biosphère. Une des problématiques liée aux composés xénobiotiques est leur transfert vers les écosystèmes aquatiques et l’altération de la diversité et des activités microbiennes. Ces communautés peuvent être impactées par ces composés, potentiellement affectant en retour les grands processus écosystémiques tels que le cycle du carbone. Ce travail de thèse vise donc à évaluer les effets d'une contamination chimique réaliste sur les processus de décomposition microbiens de la matière organique dans les écosystèmes lotiques via l’utilisation de la litière de feuilles comme descripteur.Une première partie de ces travaux de thèse a été consacrée à décrire et à comparer la décomposition microbienne (bactéries et champignons) de la litière de feuilles au travers de la structure des communautés microbiennes (structure génétique et biomasse) et les activités associées (activités enzymatiques extracellulaires) dans six bassins versants présentant des occupations des sols différentes (urbanisés, agricoles et forestier) et au cours de quatre saisons (printemps, été, automne et hiver). L'effet du gradient de contamination depuis l'amont vers aval sur ce processus a également été évalué. La décomposition microbienne s'est avérée légèrement plus élevée pour les bassins versants agricoles et urbanisés par rapport aux bassins versants forestier (contrôle), probablement en raison de l'effet de la compensation des nutriments sur les xénobiotiques. Cependant, cette compensation ne s’est avérée que partielle, la biomasse fongique ayant été considérablement réduite dans les bassins versants contaminés. Ces résultats mettent en évidence une meilleure efficacité des communautés microbiennes pour la décomposition des feuilles dans les bassins versants présentant une contamination chimique, probablement par l’intermédiaire de changements au niveau de la structure des communautés microbiennes.La deuxième partie de ces travaux de thèse consistait à évaluer in vitro les interactions entre l’eutrophisation des cours d’eau et des concentrations réalistes en pesticides (herbicides et fongicides, seuls ou en mélange) sur l’activité microbienne de décomposition de la litière de feuilles. Les fortes concentrations en nutriments (condition eutrophe) ont eu tendance à exacerber les effets des pesticides sur les taux de décomposition microbiens, suggérant que l'effet compensatoire des nutriments sur les pesticides observé dans la partie précédente dépend de la concentration et ne s'applique pas toujours aux communautés microbiennes aquatiques.De plus, une stimulation de l’activité laccase a été observée chez les communautés microbiennes exposées au fongicide, ce qui suggèrent l’utilisation de cette enzyme en tant que mécanisme de détoxification. Cependant, le fait que cette stimulation n’ait pas été observée en présence du mélange de pesticides (herbicide et fongicide) suggère que l’interaction entre ces deux composés peut altérer la capacité des communautés microbiennes à se défende contre le stress. Ces résultats constituent la première description de l'interaction potentielle entre un herbicide et un fongicide sur les communautés microbiennes associées à la litière de feuilles. (...)
Human activity through industry, urbanization and agriculture, has led to the production and release of a large amounts of chemical compounds (including pesticides and pharmaceuticals) into the biosphere. One of the problematic related to the xenobiotic compounds fate is their transfer to aquatic ecosystems and the alteration of diversity and activity of microbial communities. Microbial communities associated with immersed leaf-litter can be impacted by these compounds, and in turn, alter global processes such as the carbon and nutrient cycling in the stream ecosystem. Accordingly, this thesis work aims to assess the effects of realistic chemical contamination on microbial leaf-litter decomposition process in streams.The first chapter of this thesis was focused on the comparison of microbial decomposition activity in alder leaves in six watersheds presenting different land uses (agricultural, urbanized, forested) over four seasons (spring, summer, autumn, winter). The effect of the gradient of contamination on microbial organic matter processing from upstream to downstream sections in each watershed was also assessed. Monitoring revealed that microbial decomposition of leaves was slightly higher in contaminated watersheds (agricultural and urbanized) in comparison with control ones (forested), probably because of the compensation effect by nutrients over xenobiotics. However, this compensation mechanism was partial since fungal biomass accumulated in leaves was greatly reduced in contaminated watersheds. Overall, this highlights microbial communities being more efficient for leaf decomposition in polluted watersheds than in the less contaminated ones, which is probably explained by changes in microbial community structure.The second chapter of this thesis aimed to evaluate in vitro the specific interactions between nutrients (nitrogen and phosphorus) and pesticides (herbicide and fungicide, alone or in mixture) exposure on microbial communities during leaf-litter decomposition. High nutrient concentrations (eutrophic conditions) tended to exacerbate the effects of pesticides on leaf decomposition rates suggesting that the compensatory mechanism of nutrients over pesticides observed in the previous part is probably concentration dependent and does not always apply to aquatic microbial communities. Moreover, a stimulation in laccase activity was observed when microbial communities were exposed to the fungicide, suggesting a role of this enzyme in detoxification mechanisms. However, the fact that such stimulation was not observed when exposed to the mixture of both pesticides (herbicide and fungicide) suggest that the interaction between these two molecules impaired the ability of microbial communities to display properstress response. These results constitute the first evidence of the potential interaction between an herbicide and a fungicide on leaf-associated microbial communities functioning. (...)

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49

Cook, Paul Edward. "Studies on fungal biomass and activity associated with the decomposition of plant litter in freshwater." Thesis, London Metropolitan University, 1987. http://repository.londonmet.ac.uk/3125/.

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A clearing and staining method using 2 stains, with one acting as a counter-stain for fungi, gave higher estimates of fungal biomass than other staining methods and it correlated well with the agar film technique. Using the method, it was possible to examine the spatial distribution of hyphae on leaves which varied between leaf types and fungal species. Improvements were made to the agar film method by optimising extraction of hyphae from leaf litter and using a tetrazolium staining technique to detect metabolically active hyphae. An indirect method for estimating fungal biomass was developed using ergosterol as a marker. Conversion factors for ergosterol and biovolume to fungal biomass were shown to vary with fungal species, age and growth conditions, but no single parameter was found which could adequately explain this. In field studies on flooded gravel pits biomass was 0.02-6.66/0 leaf dry weight depending on leaf type, biomass method and submersion time. Biomass estimated using clearing and staining was significantly correlated with ergosterol and with the agar film method; the latter gave the highest estimates. In terms of allochthonous litter inputs, fungal biomass represented 0.03-16.22 kg/ha. Studies on a number of the gravel pit lakes demonstrated variation in communities of Ingoldian fungi both between lakes and within a single lake. Correlations were found with magnesium levels and litter inputs, but not with fungal biomass in the litter or cellulose decomposition. In one lake, decomposition of litter, fungal biomass and microbial populations were followed. No differences were found in biomass when animals were excluded although this influenced Ingoldian fungi. Higher numbers of Ingoldian fungi correlated with weight losses and biomass , and a competitive hierarchy was suggested to explain changes in fungal populations during decomposition.

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Nevlydov, I., V. Yevsieiev, S. Miliutina, and V. Bortnikova. "Accelerometers production technological process decomposition parameters model." Thesis, 2016 XII International Conference on Perspective Technologies and Methods in MEMS Design (MEMSTECH), 2016. http://openarchive.nure.ua/handle/document/3508.

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Dissertations / Theses on the topic 'Litter production and decomposition'

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