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Author: Ranjan Muthukrishnan Publisher: ISBN: Category : Languages : en Pages : 115
Book Description
Coral reefs have seen precipitous declines across the globe that are generally associated with transitions to reefs dominated by algae. Understanding the causes and dynamics of these transitions is of critical importance for the implementation of effective management strategies to protect reefs that remain healthy and to recover degraded reefs. To address these issues I evaluated the potential resilience of coral reefs at Isla Contadora, Panamá in the Easter Tropical Pacific (ETP), to different anthropogenic stresses with an integrated approach using empirical and modeling methods. Direct community response to stressors was investigated with experimental manipulations of herbivore abundance, nutrient supply and sediment loading. These experiments showed that any of the three stressors could push reefs toward algal dominance but that the effects of particular stressors were variable and highly dependent on the environmental context in which they were applied. In addition, I identified that herbivory rates and nutrient availability, two critical controls of community structure, vary in response to the local abundance of coral and algae. Because both processes are stronger in the community state they support they act as positive feedbacks pushing reefs toward divergent community states and producing patchy spatial patterning. Using these empirical results I developed a spatially explicit simulation model that incorporated and tested if the environmental conditions measured in the ETP supported alternative stable states (ASS). ASS theory is a dominant conceptual framework for understanding processes that support resilience of ecological communities in the face of anthropogenic disturbance, and, by combining empirical and modeling methods, I propose a rapid and non-destructive method to evaluate ASS in fragile habitats. Using the model I demonstrated that the presence of positive feedback are essential for ASS and the strength of those feedbacks is the critical factor that separates systems with phase shifts and ASS. With data from Isla Contadora I was also able to identify the particular conditions under which ETP reefs should display ASS and demonstrated that the reefs at Isla Contadora exist within that range suggesting they exist as ASS.
Author: Ranjan Muthukrishnan Publisher: ISBN: Category : Languages : en Pages : 115
Book Description
Coral reefs have seen precipitous declines across the globe that are generally associated with transitions to reefs dominated by algae. Understanding the causes and dynamics of these transitions is of critical importance for the implementation of effective management strategies to protect reefs that remain healthy and to recover degraded reefs. To address these issues I evaluated the potential resilience of coral reefs at Isla Contadora, Panamá in the Easter Tropical Pacific (ETP), to different anthropogenic stresses with an integrated approach using empirical and modeling methods. Direct community response to stressors was investigated with experimental manipulations of herbivore abundance, nutrient supply and sediment loading. These experiments showed that any of the three stressors could push reefs toward algal dominance but that the effects of particular stressors were variable and highly dependent on the environmental context in which they were applied. In addition, I identified that herbivory rates and nutrient availability, two critical controls of community structure, vary in response to the local abundance of coral and algae. Because both processes are stronger in the community state they support they act as positive feedbacks pushing reefs toward divergent community states and producing patchy spatial patterning. Using these empirical results I developed a spatially explicit simulation model that incorporated and tested if the environmental conditions measured in the ETP supported alternative stable states (ASS). ASS theory is a dominant conceptual framework for understanding processes that support resilience of ecological communities in the face of anthropogenic disturbance, and, by combining empirical and modeling methods, I propose a rapid and non-destructive method to evaluate ASS in fragile habitats. Using the model I demonstrated that the presence of positive feedback are essential for ASS and the strength of those feedbacks is the critical factor that separates systems with phase shifts and ASS. With data from Isla Contadora I was also able to identify the particular conditions under which ETP reefs should display ASS and demonstrated that the reefs at Isla Contadora exist within that range suggesting they exist as ASS.
Author: Peter W. Glynn Publisher: Springer ISBN: 9401774994 Category : Science Languages : en Pages : 666
Book Description
This book documents and examines the state of health of coral reefs in the eastern tropical Pacific region. It touches on the occurrence of coral reefs in the waters of surrounding countries, and it explores their biogeography, biodiversity and condition relative to the El Niño southern oscillation and human impacts. Additionally contained within is a field that presents information on many of the species presented in the preceding chapters.
Author: Vadim Alexandrovich Karatayev Publisher: ISBN: 9781658413640 Category : Languages : en Pages :
Book Description
When qualitatively distinct, alternatively stable ecological states occur under the same environmental conditions, disturbance can lead to abrupt and persistent ecosystem shifts. Whilst theoretically possible in simple models of many systems, empirical evidence for this phenomenon remains limited to relatively simple ecosystems. In other systems, feedback loops that underlie this dynamic might weaken due to environmental variation and species differences, reducing the relevance of alternative stable states. In this dissertation, I resolve the ecological processes that can lead to alternative stable states in heterogeneous ecosystems. In interconnected systems where environments differ among local communities, the local relevance of alternative stable states might erode as immigration overwhelms local feedbacks. In Chapter 1, I quantify how interconnectedness affects the relevance of alternative stable states using dynamical models of California rocky reef communities that incorporate observed environmental stochasticity and feedback loops. My models demonstrate the potential for localized kelp- or urchin-dominated alternative states despite high interconnectedness because feedbacks affect dispersers as they settle into local communities. Regionally, such feedbacks affecting settlement can produce a mosaic of alternative stable states that span local (10-20km) scales despite the synchronizing effect of long-distance dispersal. These predictions reflect observed scales of community states in California rocky reefs and suggest how alternative states co-occur in many marine and terrestrial systems with settlement feedbacks. Within local communities, environmental variation might limit alternative stable states to fine-scale mosaics rather than larger patches. Temperate rocky reefs exemplify each of patterned communities, local environmental variation, and feedbacks in urchin behavior. Specifically, urchins can reduce grazing activity when kelp are abundant either in local stands that attract predators and cause physical abrasion or across entire reefs when fronds detached from kelp canopies subsidize urchin diets. By fitting dynamical models to large-scale reef surveys, in Chapter 2 I show that reef-scale feedbacks can create reef-scale, alternatively stable kelp- and urchin-dominated states at 37% of sites in California. In New Zealand, local feedbacks limit this phenomenon to fine-scale mosaics at 3-8m depths with moderate wave stress on kelp, with distinct single stable states in exposed shallows and sheltered, deeper areas. My results also highlight that grazer behavior can regulate community patterning. In food webs, demographic heterogeneity and specialized interactions among species might also dissipate the feedbacks that create alternative stable states. In Chapter 3 I develop a general model of consumer-resource interactions with either specialized feedbacks where individual resources become unpalatable at high abundance or aggregate feedbacks where overall resource abundance reduces consumer recruitment. I then quantify how species differences in demography affect the potential for either feedback to produce alternatively stable consumer- or resource-dominated states. I find that alternative stable states can be relevant to multispecies food webs with aggregated feedbacks, greater interconnectedness, and lower species differences. Where specialized feedbacks occur, I highlight a greater potential for the sudden collapse of many species at low stress levels when vulnerable species uniquely contributing to guild persistence collapse. Simpler models that aggregate species into groups omit this reduced resilience under low redundancy in species roles.
Author: John C. Moore Publisher: Cambridge University Press ISBN: 1107182115 Category : Business & Economics Languages : en Pages : 445
Book Description
This book presents new approaches to studying food webs, using practical and policy examples to demonstrate the theory behind ecosystem management decisions.
Author: Jacqueline L. Padilla-Gamiño Publisher: Taylor Trade Publishing ISBN: 1589797574 Category : Juvenile Nonfiction Languages : en Pages : 34
Book Description
Kupe and the Corals is the story of Kupe, a young boy who undertakes an amazing voyage of discovery to learn about corals and the importance of coral reefs to all of the many animals that depend upon them. One night while he is fishing with his father, Kupe observes an astonishing event, thousands and thousands of tiny “bubbles” rising to the surface of the waters in the lagoon near where he lives. Kupe is amazed by this sight and wants to learn more about the “strange pink bubbles” that he has captured in an old jam jar. Kupe visits with an elder from his village and a scientist from the nearby marine lab in an attempt to learn more about what he has seen. During his conversations, Kupe learns that what he has captured are tiny coral larvae, baby corals that are produced in the millions over just a few nights each year by the adult corals living in the lagoon. Kupe then goes on to learn more about how corals grow and the importance of corals in building the reefs that provide homes for all of the other wonderful animals that he sees while snorkeling in the lagoon. Now, realizing how important the larvae he has captured are to the health of the coral reef, Kupe happily returns his larvae to the sea. Kupe and the Corals, is the sixth book in the Long Term Ecological Research Network Series.
Author: David D. Briske Publisher: Springer ISBN: 3319467093 Category : Technology & Engineering Languages : en Pages : 664
Book Description
This book is open access under a CC BY-NC 2.5 license. This book provides an unprecedented synthesis of the current status of scientific and management knowledge regarding global rangelands and the major challenges that confront them. It has been organized around three major themes. The first summarizes the conceptual advances that have occurred in the rangeland profession. The second addresses the implications of these conceptual advances to management and policy. The third assesses several major challenges confronting global rangelands in the 21st century. This book will compliment applied range management textbooks by describing the conceptual foundation on which the rangeland profession is based. It has been written to be accessible to a broad audience, including ecosystem managers, educators, students and policy makers. The content is founded on the collective experience, knowledge and commitment of 80 authors who have worked in rangelands throughout the world. Their collective contributions indicate that a more comprehensive framework is necessary to address the complex challenges confronting global rangelands. Rangelands represent adaptive social-ecological systems, in which societal values, organizations and capacities are of equal importance to, and interact with, those of ecological processes. A more comprehensive framework for rangeland systems may enable management agencies, and educational, research and policy making organizations to more effectively assess complex problems and develop appropriate solutions.
Author: Adrian C. Newton Publisher: Cambridge University Press ISBN: 1108472737 Category : Nature Languages : en Pages : 493
Book Description
Examines how ecosystems can collapse as a result of human activity, and the ecological processes underlying their subsequent recovery.
Author: Volker Grimm Publisher: Princeton University Press ISBN: 1400850622 Category : Science Languages : en Pages : 445
Book Description
Individual-based models are an exciting and widely used new tool for ecology. These computational models allow scientists to explore the mechanisms through which population and ecosystem ecology arises from how individuals interact with each other and their environment. This book provides the first in-depth treatment of individual-based modeling and its use to develop theoretical understanding of how ecological systems work, an approach the authors call "individual-based ecology.? Grimm and Railsback start with a general primer on modeling: how to design models that are as simple as possible while still allowing specific problems to be solved, and how to move efficiently through a cycle of pattern-oriented model design, implementation, and analysis. Next, they address the problems of theory and conceptual framework for individual-based ecology: What is "theory"? That is, how do we develop reusable models of how system dynamics arise from characteristics of individuals? What conceptual framework do we use when the classical differential equation framework no longer applies? An extensive review illustrates the ecological problems that have been addressed with individual-based models. The authors then identify how the mechanics of building and using individual-based models differ from those of traditional science, and provide guidance on formulating, programming, and analyzing models. This book will be helpful to ecologists interested in modeling, and to other scientists interested in agent-based modeling.
Author: Intergovernmental Panel on Climate Change (IPCC) Publisher: Cambridge University Press ISBN: 9781009157971 Category : Science Languages : en Pages : 755
Book Description
The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.
Author: Pat Hutchings Publisher: CSIRO PUBLISHING ISBN: 0643099972 Category : Science Languages : en Pages : 396
Book Description
The Great Barrier Reef Marine Park is 344 400 square kilometres in size and is home to one of the most diverse ecosystems in the world. This comprehensive guide describes the organisms and ecosystems of the Great Barrier Reef, as well as the biological, chemical and physical processes that influence them. Contemporary pressing issues such as climate change, coral bleaching, coral disease and the challenges of coral reef fisheries are also discussed. In addition,the book includes a field guide that will help people to identify the common animals and plants on the reef, then to delve into the book to learn more about the roles the biota play. Beautifully illustrated and with contributions from 33 international experts, The Great Barrier Reef is a must-read for the interested reef tourist, student, researcher and environmental manager. While it has an Australian focus, it can equally be used as a baseline text for most Indo-Pacific coral reefs. Winner of a Whitley Certificate of Commendation for 2009.
Author: Ranjan Muthukrishnan
Author: Ranjan Muthukrishnan
Author: Peter W. Glynn
Author: Vadim Alexandrovich Karatayev
Author: John C. Moore
Author: Jacqueline L. Padilla-Gamiño
Author: David D. Briske
Author: Adrian C. Newton
Author: Volker Grimm
Author: Intergovernmental Panel on Climate Change (IPCC)
Author: Pat Hutchings