Download or read book Self limitation as an Explanation for Species Relative Abundances and the Long term Persistence of Rare Species written by Glenda Marie Yenni and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of ecological theory describes species interactions. These interactions often play an important theoretical role in facilitating coexistence. In particular, rarity in ecological communities, though often observed, provides a significant challenge to theoretical and empirical ecologists alike. I use a plant community model to simulate the effect of stronger negative frequency dependence on the long-term persistence of the rare species in a simulated community. This strong self-limitation produces long persistence times for the rare competitor, which otherwise succumb quickly to stochastic extinction. The results suggest that the mechanism causing species to be rare in this case is the same mechanism allowing those species to persist. To determine if ecological communities generally show the theoretical pattern, I estimate the strength of frequency-dependent population dynamics using species abundance data from 90 communities across a broad range of environments and taxonomic groups. In approximately half of the analyzed communities, rare species showed disproportionately strong negative frequency dependence. In particular, a pattern of increasing frequency dependence with decreasing relative abundance was seen in these communities, signaling the importance of this mechanism for rare species specifically. Insight into the special population dynamics of rare species will inform conservation efforts in response to climate change and other disturbance. Further difficulties in the detection of theoretical patterns in ecological data may be a result of the ecological currency used. Though ecologists typically use abundance data to test theories, energy use is another ecological currency that may be more relevant in some cases. In particular when detecting patterns that are a result of species interactions, the currency used should be the one in which those interactions actually operate. I compare the results of using abundance and energy use to detect two processes with well-defined expectations. The first is a description of population dynamics, the above described relationship between relative abundance and self-limitation. The second, compensatory dynamics, is a description of community-level dynamics. I find that the currency used alters the results, and thus the species-level implications. It does not, however, alter the overall pattern that would have theoretical implications. Results in both currencies support the pattern of strong self-limitation for persistent rare species.
Download or read book Power written by Richard Heinberg and published by New Society Publishers. This book was released on 2021-09-14 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: Impeccably researched and masterfully written, this book explains how and why humanity is driving itself off the cliff. — Dahr Jamail, author, The End of Ice Weaving together findings from a wide range of disciplines, Power traces how four key elements developed to give humans extraordinary power: tool making ability, language, social complexity, and the ability to harness energy sources ― most significantly, fossil fuels. It asks whether we have, at this point, overpowered natural and social systems, and if we have, what we can do about it. Has Homo sapiens — one species among millions — become powerful enough to threaten a mass extinction and disrupt the Earth's climate? Why have we developed so many ways of oppressing one another? Can we change our relationship with power to avert ecological catastrophe, reduce social inequality, and stave off collapse? These questions — and their answers — will determine our fate.
Download or read book Rarity written by K.J. Gaston and published by Springer Science & Business Media. This book was released on 1994-07-31 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on rarity, its spatial and temporal dynamics, causes, and interaction with conservation. Although they can be viewed from many different perspectives, rare species are of particular concern to conservationists because they tend to have a greater probability of extinction. This book therefore identifies a number of important issues both heuristic and practical.
Download or read book The Biology of Rarity written by W.E. Kunin and published by Springer Science & Business Media. This book was released on 1996-12-31 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book began life as a review article. That article spawned a symposium which was, in turn, greatly expanded to form the present volume. As the project moved through these developmental stages (hopefully, towards attainment of its full maturity), a number of people have provided invaluable assistance to us, and we would like to take this opportunity to thank them. Gordon Orians must certainly take a high place in that list. He has been both a friend and mentor to W.E.K., and many of the topics explored in this book have emerged from the resultant dialogue. His thought processes, ideas and perhaps even some of his turns of phrase emerge throughout much ofthe book. Gordon also played a pivotal role in inviting in motion, and so he has served as a catalyst the article that set this project to the book as well as one of its reagents. While he has not served as an editor of this book, he is one of its authors in more than just the literal sense.
Download or read book Conservation Biology written by Scott P. Carroll and published by Oxford University Press. This book was released on 2008-09-15 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main goal of this book is to encourage and formalize the infusion of evolutionary thinking into mainstream conservation biology. It reviews the evolutionary foundations of conservation issues, and unifies conceptual and empirical advances in evolutionary conservation biology. The book can be used either as a primary textbook or as a supplementary reading in an advanced undergraduate or graduate level course - likely to be called Conservation Biology or in some cases Evolutionary Ecology. The focus of chapters is on current concepts in evolution as they pertain to conservation, and the empirical study of these concepts. The balanced treatment avoids exhaustive reviews and overlapping duplication among the chapters. Little background in genetics is assumed of the reader.
Download or read book Causes and Consequences of Grass Versus Forb Years in California Rangelands written by Lauren Margaret Hallett and published by . This book was released on 2015 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global circulation models consistently forecast an increase in the frequency of extreme events such as severe storms and droughts. These changes will alter species interactions and ecosystem functions shaped by precipitation, such as productivity. Ecosystem management will need to anticipate, and where possible, mitigate the effects of increased climate variability in order to maintain ecosystem services and biodiversity. This is a pressing issue for California rangelands, which host a high percentage of California's endemic plants and support a large ranching industry that depends on reliable forage production. My dissertation uses observational and experimental approaches to understand the implications of increased precipitation variability for the stability of forage production (i.e. aboveground productivity) and the persistence of rare species in California rangelands. Chapter 1 explores how species interactions affect the stability of aboveground productivity and whether these patterns change along precipitation gradients. I compiled and analyzed nine long-term datasets of plant species composition and aboveground productivity from grassland sites across the United States. I found that productivity in mesic grasslands was stabilized by species richness, whereas productivity in climatically variable grasslands was stabilized by species asynchrony over time. The latter pattern was exemplified by California rangelands, which experienced the most variable precipitation as well as exhibited the most species asynchrony. Chapters 2 and 3 experimentally test the relationship between precipitation variability and species asynchrony in California rangelands and its implications for the stability of cover and aboveground productivity over time. In Chapter 2, I used rainout shelters and irrigation to experimentally create dry and wet conditions, which I replicated across areas with both low and moderate grazing histories. In moderately grazed areas, my rainfall treatments generated a classic pattern of "grass years" in wet conditions and "forb years" in dry. This pattern helped to stabilize cover across rainfall treatments and is a likely reason for the relationship between precipitation variability and species asynchrony that I observed in Chapter 1. In low grazed areas, however, my treatments essentially generated "grass years" in wet conditions and "no-grass years" in dry; forb cover was both low and unresponsive to rainfall in these areas. This suggests that moderate grazing may be an important management tool to maintain the functional responsiveness of California rangelands to precipitation variability. Chapter 3 tests whether competitive and functional differences between grasses and forbs affect the degree to which asynchrony stabilizes total biomass production. Within wet and dry plots I manipulated species interactions to create monocultures of Avena barbata (the most abundant grass), Erodium botrys (the most abundant forb) and a mixture of Avena and Erodium. I found that Avena exerted a stronger competitive effect on Erodium under wet conditions relative to dry, which should help stabilize community productivity. However, this effect was overwhelmed by highly unequal production capacity between the two species; Erodium productivity was much lower than Avena and, consequently, tradeoffs between the species did not increase the stability of the mixture relative to either monoculture. Chapter 4 further investigates tradeoffs between grass and forb years, but in the context of species population dynamics in a ecosystem of conservation concern. Serpentine grassland patches in California host a unique, predominately native flora that is threatened by non-native grass invasion. I focused on a serpentine site that over the past 32 years has exhibited high fluctuations in native forb abundances, and has experienced a series of invasions and subsequent recessions by a non-native annual grass, Bromus hordeaceus. Effective native species conservation and invasive species management require an understanding of what drives such variation in species abundances. I applied a population model to the six most-abundant species at the site - four native annual forbs, a native annual grass and Bromus - to test factors affecting their population size and stability. I found that species could have large population sizes (measured as mean abundance over time) for different reasons - three species had high intrinsic growth rates, whereas the other three, including Bromus and the native grass, had minimal self-limitation. Population stability was highly affected by these differences: species with both low intrinsic growth rates and minimal self-limitation had less stable populations and were more sensitive to rainfall. These findings suggest a framework to describe population stability and to identify which species are likely to be sensitive to environmental change.
Download or read book The Species Area Relationship written by Thomas J. Matthews and published by Cambridge University Press. This book was released on 2021-03-18 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a comprehensive synthesis of a fundamental phenomenon, the species-area relationship, addressing theory, evidence and application.
Download or read book The Ohio Journal of Science written by and published by . This book was released on 1998 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes book reviews and abstracts.
Download or read book Proceedings of the New Zealand Grassland Association written by New Zealand Grassland Association and published by . This book was released on 1996 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Structure and Dynamics of Geographic Ranges written by Kevin J. Gaston and published by Oxford University Press, USA. This book was released on 2003 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: A synthesis of present understanding of the structure of the geographic ranges of species, which is a core issue in ecology and biogeography with implications for many of the environmental issues presently facing humankind.
Download or read book The Endangered Species Act written by Stanford Environmental Law Society and published by Stanford Environmental Law Soc. This book was released on 2001 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook is a guide to the federal Endangered Species Act, the primary U.S. law aimed at protecting species of animals and plants from human threats to their survival. It is intended for lawyers, government agency employees, students, community activists, businesspeople, and any citizen who wants to understand the Act--its history, provisions, accomplishments, and failures.
Download or read book Bulletin of the Atomic Scientists written by and published by . This book was released on 1971-09 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Download or read book Environmental DNA written by Pierre Taberlet and published by Oxford University Press. This book was released on 2018-02-02 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental DNA (eDNA) refers to DNA that can be extracted from environmental samples (such as soil, water, feces, or air) without the prior isolation of any target organism. The analysis of environmental DNA has the potential of providing high-throughput information on taxa and functional genes in a given environment, and is easily amenable to the study of both aquatic and terrestrial ecosystems. It can provide an understanding of past or present biological communities as well as their trophic relationships, and can thus offer useful insights into ecosystem functioning. There is now a rapidly-growing interest amongst biologists in applying analysis of environmental DNA to their own research. However, good practices and protocols dealing with environmental DNA are currently widely dispersed across numerous papers, with many of them presenting only preliminary results and using a diversity of methods. In this context, the principal objective of this practical handbook is to provide biologists (both students and researchers) with the scientific background necessary to assist with the understanding and implementation of best practices and analyses based on environmental DNA.
Download or read book Biological Diversity written by Anne E. Magurran and published by Oxford University Press. This book was released on 2011 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an up to date review of the methods of measuring and assessing biological diversity, together with their application.
Download or read book Metapopulation Ecology written by Ilkka Hanski and published by Oxford University Press. This book was released on 1999-03-18 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by a world renowned biologist, this volume offers a comprehensive synthesis of current research in this rapidly expanding area of population biology. It covers both the essential theory and a wide range of empirical studies, including the author's groundbreaking work on the Glanville fritillary butterfly. It also includes practical applications to conservation biology. The book describes theoretical models for metapopulation dynamics in highly fragmented landscapes and emphasizes spatially realistic models. It presents the incidence function model and includes several detailed examples of its application. Accessible to advanced undergraduate and graduate students, Metapopulation Ecology will be a valuable resource for researchers in population biology, conservation biology, and landscape ecology.
Download or read book Bulletin of the Atomic Scientists written by and published by . This book was released on 1955-11 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Download or read book The Theory of Island Biogeography written by Robert H. MacArthur and published by Princeton University Press. This book was released on 2001 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Population theory.
