Quantifying the Effects of Spatial Environmental Variation on Dynamics of Natural Plant Populations PDF Download

Author: Anna Louise Warwick Sears
Publisher:
ISBN:
Category :
Languages : en
Pages : 334

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Author: Gaurav Sunil Kandlikar
Publisher:
ISBN:
Category :
Languages : en
Pages : 181

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Understanding the processes that determine the diversity and dynamics of plant communities is a longstanding challenge in ecology. Many studies have inferred the role of demographic processes by studying patterns of functional trait variation in natural communities, but studies explicitly linking such functional trait differences to demographic processes are lacking. There has also been a growing realization that the dynamics of plant communities are also influenced by the composition of the soil microbial community, but despite hundreds of empirical studies, predicting the influence of soil microbes on the diversity and dynamics of natural plant communities remains a challenge. In my dissertation I couple ecological theory with field and greenhouse experiments to build a more complete and generalizable understanding of the processes that control plant biodiversity. In Chapter One, I ask whether community-wide shifts in three key plant functional traits across an environmental gradient reflect variation in the trait-performance relationship across the landscape. To address this question I coupled observational data of variation in plant composition and functional with experimental data on species performance across the same landscape. I asked whether observed trait-environment interactions in the experimental data match observed patterns of trait variation. I found that shifts in community-weighted mean traits generally reflect the direction of trait-environment interactions. But on the whole, the interactions we found were weak, and by themselves might not be sufficient to explain community-wide shifts. This supports the value of plant functional traits for predicting species responses to environmental variation, and highlights a need for more detailed evaluation of how trait-performance relationships change across environments to improve such predictions. Chapters Two and Three focus on how soil microbes can influence diversity in plant communities. Chapter Two begins with a re-analysis of a classic framework that has been extensively used to study how feedbacks between plants and soil microbes can influence species coexistence. A great deal of existing theoretical and empirical work has shown that soil microbes can promote plant coexistence when they generate stabilizing feedback loops, or can drive exclusion when they generate destabilizing feedback loops. I applied insights from modern coexistence theory to show that existing work has largely neglected another avenue by which plant-soil feedbacks can mediate plant coexistence, by driving average fitness differences between plants. This chapter also extends classic models of plant-soil feedback to include more biological detail to show how the effects of plant-soil feedback on plant coexistence depends critically on how plants interact with each other through other processes like resource competition. In the final chapter of my dissertation, I applied the insights from Chapter Two to ask how plant-soil feedbacks influence diversity in southern California annual grassland communities. I conducted a greenhouse experiment to quantify microbially mediated stabilization and fitness differences among fifteen pairs of annual plants. We found that soil microbes frequently generate negative frequency-dependent dynamics that stabilize plant interactions, but they simultaneously generate large average fitness differences between species. The net result is that if the plant species are otherwise competitively equivalent, soil microbes would often drive exclusion among the focal species. This work illustrates the importance of quantifying microbially mediated fitness differences, and points to important avenues for future studies on how soil microbes shape plant diversity.

Author: Igor Pavlinov
Publisher: BoD – Books on Demand
ISBN: 9533077948
Category : Science
Languages : en
Pages : 380

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The book covers several topics of biodiversity researches and uses, containing 17 chapters grouped into 5 sections. It begins with an interesting chapter considering the ways in which the very biodiversity could be thought about. Noteworthy is the chapter expounding pretty original "creativity theory of ecosystem". There are several chapters concerning models describing relation between ecological niches and diversity maintenance, the factors underlying avian species imperilment, and diversity turnover rate of a local beetle group. Of special importance is the chapter outlining a theoretical model for morphological disparity in its most widened treatment. Several chapters consider regional aspects of biodiversity in Europe, Asia, Central and South America, among them an approach for monitoring conservation of the regional tropical phytodiversity in India is of special importance. Of interest is also a chapter considering the history of the very idea of biodiversity emergence in ecological researches.

Author: Russell Lande
Publisher: OUP Oxford
ISBN: 9780198525257
Category : Mathematics
Languages : en
Pages : 698

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1. Demographic and environmental stochasticity -- 2. Extinction dynamics -- 3. Age structure -- 4. Spatial structure -- 5. Population viability analysis -- 6. Sustainable harvesting -- 7. Species diversity -- 8. Community dynamics.

Author: Marcel Holyoak
Publisher: University of Chicago Press
ISBN: 0226350649
Category : Nature
Languages : en
Pages : 527

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Takes the hallmarks of metapopulation theory to the next level by considering a group of communities, each of which may contain numerous populations, connected by species interactions within communities and the movement of individuals between communities. This book seeks to understand how communities work in fragmented landscapes.

Author: Roger Cousens
Publisher: OUP Oxford
ISBN: 0191538396
Category : Science
Languages : en
Pages : 240

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This advanced textbook is the first to explore the consequences of plant dispersal for population and community dynamics, spatial patterns, and evolution. It successfully integrates a rapidly expanding body of theoretical and empirical research. · The first comprehensive treatment of plant dispersal set within a population framework · Examines both the processes and consequence of dispersal · Spans the entire range of research, from natural history and collection of empirical data to modeling and evolutionary theory · Provides a clear and simple explanation of mathematical concepts

Author:
Publisher: Fundacion BBVA
ISBN: 8496515532
Category : Ecology
Languages : en
Pages : 505

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Author: Andrew P. Hendry
Publisher: Princeton University Press
ISBN: 0691204179
Category : Science
Languages : en
Pages : 410

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In recent years, scientists have realized that evolution can occur on timescales much shorter than the 'long lapse of ages' emphasized by Darwin - in fact, evolutionary change is occurring all around us all the time. This work provides an authoritative and accessible introduction to eco-evolutionary dynamics, a cutting-edge new field that seeks to unify evolution and ecology into a common conceptual framework focusing on rapid and dynamic environmental and evolutionary change.

Author: Melissa Kay McCormick
Publisher:
ISBN:
Category : Danthonia
Languages : en
Pages : 320

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 96

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The relative importance of density-dependent and density-independent factors in determining the population dynamics of plants has been widely debated with little resolution. In this thesis, the author explores the effects of density-dependent population regulation on population dynamics in Cardamine pensylvanica, an annual plant. In the first chapter, she shows that experimental populations of C. pensylvanica cycled from high to low density in controlled constant-environment conditions. These cycles could not be explained by external environmental changes or simple models of direct density dependence (N{sub t+1} = f[N{sub t}]), but they could be explained by delayed density dependence (N{sub t+1} = f[N{sub t}, N{sub t+1}]). In the second chapter, she shows that the difference in the stability properties of population growth models with and without delayed density dependence is due to the presence of Hopf as well as slip bifurcations from stable to chaotic population dynamics. She also measures delayed density dependence due to effects of parental density on offspring quality in C. pensylvanica and shows that this is large enough to be the cause of the population dynamics observed in C. pensylvanica. In the third chapter, the author extends her analyses of density-dependent population growth models to include interactions between competing species. In the final chapter, she compares the effects of fixed spatial environmental variation and variation in population size on the evolutionary response of C. pensylvanica populations.