The Relative Importance of Competition and Predation Varies with Productivity in a Model Community
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Biogeography, Community Structure and Biological Habitat Types of Subtidal Reefs on the South Island West Coast, New Zealand
Biogeography, community structure and biological habitat types of subtidal reefs on the South Island West Coast, New Zealand SCIENCE FOR CONSERVATION 281 Biogeography, community structure and biological habitat types of subtidal reefs on the South Island West Coast, New Zealand Nick T. Shears SCIENCE FOR CONSERVATION 281 Published by Science & Technical Publishing Department of Conservation PO Box 10420, The Terrace Wellington 6143, New Zealand Cover: Shallow mixed turfing algal assemblage near Moeraki River, South Westland (2 m depth). Dominant species include Plocamium spp. (yellow-red), Echinothamnium sp. (dark brown), Lophurella hookeriana (green), and Glossophora kunthii (top right). Photo: N.T. Shears Science for Conservation is a scientific monograph series presenting research funded by New Zealand Department of Conservation (DOC). Manuscripts are internally and externally peer-reviewed; resulting publications are considered part of the formal international scientific literature. Individual copies are printed, and are also available from the departmental website in pdf form. Titles are listed in our catalogue on the website, refer www.doc.govt.nz under Publications, then Science & technical. © Copyright December 2007, New Zealand Department of Conservation ISSN 1173–2946 (hardcopy) ISSN 1177–9241 (web PDF) ISBN 978–0–478–14354–6 (hardcopy) ISBN 978–0–478–14355–3 (web PDF) This report was prepared for publication by Science & Technical Publishing; editing and layout by Lynette Clelland. Publication was approved by the Chief Scientist (Research, Development & Improvement Division), Department of Conservation, Wellington, New Zealand. In the interest of forest conservation, we support paperless electronic publishing. When printing, recycled paper is used wherever possible. CONTENTS Abstract 5 1. Introduction 6 2. -
Genetic Methods for Estimating the Effective Size of Cetacean Populations
Genetic Methods for Estimating the Effective Size of Cetacean Populations Robin S. Waples Northwest Fisheries Center, National Marine Fisheries Service, 2725 Montlake Boulevard East, Seattle, Washington 98112, USA ABSTRACT Some indirect (genetic) methods for estimating effective population size (N,) are evaluated for their suitability in studyingcetacean populations. The methodscan be grouped into those that (1) estimate current N,, (2) estimate long-term N, and (3) provide information about recent genetic bottlenecks. The methods that estimate current effective size are best suited for the analysis of small populations. and nonrandom sampling and population subdivision are probably the most serious sources of potential bias. Methods that estimate long-term N, are best suited to the analysis of large populations or entire species, may be more strongly influenced by natural selection and depend on accurate estimates of mutation or DNA base substitution rates. Precision of the estimates of N, is likely to be a limiting factor in many applications of the indirect methods. Keywords: genetics; assessment: cetaceans - general: evolution. INTRODUCTION Population size is one of the most important factors that determine the rate of various evolutionary processes, and it appears as a parameter in many of the fundamental equations of population genetics. However, knowledge merely of the total number of individuals (N) in a population is not sufficient for an accurate description of these evolutionary processes. Because of the influence of demographic parameters, two populations of the same total size may experience very different rates of genetic change. Wright (1931; 1938) developed the concept of effective population size (N,) as a way of summarising relevant demographic information so that one can predict the evolutionary consequences of finite population size (see Fig. -
Ecological Principles and Function of Natural Ecosystems by Professor Michel RICARD
Intensive Programme on Education for sustainable development in Protected Areas Amfissa, Greece, July 2014 ------------------------------------------------------------------------ Ecological principles and function of natural ecosystems By Professor Michel RICARD Summary 1. Hierarchy of living world 2. What is Ecology 3. The Biosphere - Lithosphere - Hydrosphere - Atmosphere 4. What is an ecosystem - Ecozone - Biome - Ecosystem - Ecological community - Habitat/biotope - Ecotone - Niche 5. Biological classification 6. Ecosystem processes - Radiation: heat, temperature and light - Primary production - Secondary production - Food web and trophic levels - Trophic cascade and ecology flow 7. Population ecology and population dynamics 8. Disturbance and resilience - Human impacts on resilience 9. Nutrient cycle, decomposition and mineralization - Nutrient cycle - Decomposition 10. Ecological amplitude 11. Ecology, environmental influences, biological interactions 12. Biodiversity 13. Environmental degradation - Water resources degradation - Climate change - Nutrient pollution - Eutrophication - Other examples of environmental degradation M. Ricard: Summer courses, Amfissa July 2014 1 1. Hierarchy of living world The larger objective of ecology is to understand the nature of environmental influences on individual organisms, populations, communities and ultimately at the level of the biosphere. If ecologists can achieve an understanding of these relationships, they will be well placed to contribute to the development of systems by which humans -
Community Ecology
Schueller 509: Lecture 12 Community ecology 1. The birds of Guam – e.g. of community interactions 2. What is a community? 3. What can we measure about whole communities? An ecology mystery story If birds on Guam are declining due to… • hunting, then bird populations will be larger on military land where hunting is strictly prohibited. • habitat loss, then the amount of land cleared should be negatively correlated with bird numbers. • competition with introduced black drongo birds, then….prediction? • ……. come up with a different hypothesis and matching prediction! $3 million/yr Why not profitable hunting instead? (Worked for the passenger pigeon: “It was the demographic nightmare of overkill and impaired reproduction. If you’re killing a species far faster than they can reproduce, the end is a mathematical certainty.” http://www.audubon.org/magazine/may-june- 2014/why-passenger-pigeon-went-extinct) Community-wide effects of loss of birds Schueller 509: Lecture 12 Community ecology 1. The birds of Guam – e.g. of community interactions 2. What is a community? 3. What can we measure about whole communities? What is an ecological community? Community Ecology • Collection of populations of different species that occupy a given area. What is a community? e.g. Microbial community of one human “YOUR SKIN HARBORS whole swarming civilizations. Your lips are a zoo teeming with well- fed creatures. In your mouth lives a microbiome so dense —that if you decided to name one organism every second (You’re Barbara, You’re Bob, You’re Brenda), you’d likely need fifty lifetimes to name them all. -
Lecture 33 May 9 Species Interactions – Competition 2007
Figure 49.14 upper left 7.014 Lecture 33 May 9 Species Interactions – Competition 2007 Consumptive competition occurs when organisms compete for the same resources. These trees are competing for nitrogen and other nutrients. Figure 49.14 upper right Figure 49.14 middle left Preemptive competition occurs when individuals occupy space and prevent access Overgrowth competition occurs when an organism grows over another, blocking to resources by other individuals. The space preempted by these barnacles is access to resources. This large fern has overgrown other individuals and is unavailable to competitors. shading them. 1 Figure 49.14 middle right Figure 49.14 lower left Chemical competition occurs when one species produces toxins that negatively Territorial competition occurs when mobile organisms protect a feeding or affect another. Note how few plants are growing under these Salvia shrubs. breeding territory. These red-winged blackbirds are displaying to each other at a territorial boundary. Figure 49.14 lower left The Fundamental Ecological Niche: “An n-dimensional hyper-volume every point on which a species can survive and reproduce indefinitely in the absence of other species” (Hutchinson) y t i d i m u h e iz tem s pe d Encounter competition occurs when organisms interfere directly with each other’s ra oo tur F access to specific resources. Here, spotted hyenas and vultures fight over a kill. e 2 The Realized Ecological Niche: the niche actually occupied in the presence of other species niche overlap leads to competition y t i d i -
Maximum Sustainable Yield from Interacting Fish Stocks in an Uncertain World: Two Policy Choices and Underlying Trade-Offs Arxiv
Maximum sustainable yield from interacting fish stocks in an uncertain world: two policy choices and underlying trade-offs Adrian Farcas Centre for Environment, Fisheries & Aquaculture Science Pakefield Road, Lowestoft NR33 0HT, United Kingdom [email protected] Axel G. Rossberg∗ Queen Mary University of London, School of Biological and Chemical Sciences, 327 Mile End Rd, London E1, United Kingdom and Centre for Environment, Fisheries & Aquaculture Science Pakefield Road, Lowestoft NR33 0HT, United Kingdom [email protected] 26 May 2016 c Crown copyright Abstract The case of fisheries management illustrates how the inherent structural instability of ecosystems can have deep-running policy implications. We contrast ten types of management plans to achieve maximum sustainable yields (MSY) from multiple stocks and compare their effectiveness based on a management strategy evalua- tion (MSE) that uses complex food webs in its operating model. Plans that target specific stock sizes (BMSY) consistently led to higher yields than plans targeting spe- cific fishing pressures (FMSY). A new self-optimising control rule, introduced here arXiv:1412.0199v6 [q-bio.PE] 31 May 2016 for its robustness to structural instability, led to intermediate yields. Most plans outperformed single-species management plans with pressure targets set without considering multispecies interactions. However, more refined plans to \maximise the yield from each stock separately", in the sense of a Nash equilibrium, produced total yields comparable to plans aiming to maximise total harvested biomass, and were more robust to structural instability. Our analyses highlight trade-offs between yields, amenability to negotiations, pressures on biodiversity, and continuity with current approaches in the European context. -
How to Quantify Competitive Ability
Received: 7 December 2017 | Accepted: 8 February 2018 DOI: 10.1111/1365-2745.12954 ESSAY REVIEW How to quantify competitive ability Simon P. Hart1 | Robert P. Freckleton2 | Jonathan M. Levine1 1Institute of Integrative Biology, ETH Zürich (Swiss Federal Institute of Technology), Abstract Zürich, Switzerland 1. Understanding the role of competition in structuring communities requires that we 2 Department of Animal and Plant quantify competitive ability in a way that permits us to predict the outcome of com- Sciences, University of Sheffield, Sheffield, UK petition over the long term. Given such a clear goal for a process that has been the focus of ecological research for decades, there is surprisingly little consensus on how Correspondence Simon P. Hart to measure competitive ability, with up to 50 different metrics currently proposed. Email: [email protected] 2. Using competitive population dynamics as a foundation, we define competitive Handling Editor: Hans de Kroon ability—the ability of one species to exclude another—using quantitative theoreti- cal models of population dynamics to isolate the key parameters that are known to predict competitive outcomes. 3. Based on the definition of competitive ability we identify the empirical require- ments and describe straightforward methods for quantifying competitive ability in future empirical studies. In doing so, our analysis also allows us to identify why many existing approaches to studying competition are unsuitable for quantifying competitive ability. 4. Synthesis. Competitive ability is precisely defined starting from models of com- petitive population dynamics. Quantifying competitive ability in a theoretically justified manner is straightforward using experimental designs readily applied to studies of competition in the laboratory and field. -
Can More K-Selected Species Be Better Invaders?
Diversity and Distributions, (Diversity Distrib.) (2007) 13, 535–543 Blackwell Publishing Ltd BIODIVERSITY Can more K-selected species be better RESEARCH invaders? A case study of fruit flies in La Réunion Pierre-François Duyck1*, Patrice David2 and Serge Quilici1 1UMR 53 Ӷ Peuplements Végétaux et ABSTRACT Bio-agresseurs en Milieu Tropical ӷ CIRAD Invasive species are often said to be r-selected. However, invaders must sometimes Pôle de Protection des Plantes (3P), 7 chemin de l’IRAT, 97410 St Pierre, La Réunion, France, compete with related resident species. In this case invaders should present combina- 2UMR 5175, CNRS Centre d’Ecologie tions of life-history traits that give them higher competitive ability than residents, Fonctionnelle et Evolutive (CEFE), 1919 route de even at the expense of lower colonization ability. We test this prediction by compar- Mende, 34293 Montpellier Cedex, France ing life-history traits among four fruit fly species, one endemic and three successive invaders, in La Réunion Island. Recent invaders tend to produce fewer, but larger, juveniles, delay the onset but increase the duration of reproduction, survive longer, and senesce more slowly than earlier ones. These traits are associated with higher ranks in a competitive hierarchy established in a previous study. However, the endemic species, now nearly extinct in the island, is inferior to the other three with respect to both competition and colonization traits, violating the trade-off assumption. Our results overall suggest that the key traits for invasion in this system were those that *Correspondence: Pierre-François Duyck, favoured competition rather than colonization. CIRAD 3P, 7, chemin de l’IRAT, 97410, Keywords St Pierre, La Réunion Island, France. -
COULD R SELECTION ACCOUNT for the AFRICAN PERSONALITY and LIFE CYCLE?
Person. individ.Diff. Vol. 15, No. 6, pp. 665-675, 1993 0191-8869/93 S6.OOf0.00 Printedin Great Britain.All rightsreserved Copyright0 1993Pergamon Press Ltd COULD r SELECTION ACCOUNT FOR THE AFRICAN PERSONALITY AND LIFE CYCLE? EDWARD M. MILLER Department of Economics and Finance, University of New Orleans, New Orleans, LA 70148, U.S.A. (Received I7 November 1992; received for publication 27 April 1993) Summary-Rushton has shown that Negroids exhibit many characteristics that biologists argue result from r selection. However, the area of their origin, the African Savanna, while a highly variable environment, would not select for r characteristics. Savanna humans have not adopted the dispersal and colonization strategy to which r characteristics are suited. While r characteristics may be selected for when adult mortality is highly variable, biologists argue that where juvenile mortality is variable, K character- istics are selected for. Human variable birth rates are mathematically similar to variable juvenile birth rates. Food shortage caused by African drought induce competition, just as food shortages caused by high population. Both should select for K characteristics, which by definition contribute to success at competition. Occasional long term droughts are likely to select for long lives, late menopause, high paternal investment, high anxiety, and intelligence. These appear to be the opposite to Rushton’s r characteristics, and opposite to the traits he attributes to Negroids. Rushton (1985, 1987, 1988) has argued that Negroids (i.e. Negroes) were r selected. This idea has produced considerable scientific (Flynn, 1989; Leslie, 1990; Lynn, 1989; Roberts & Gabor, 1990; Silverman, 1990) and popular controversy (Gross, 1990; Pearson, 1991, Chapter 5), which Rushton (1989a, 1990, 1991) has responded to. -
Where Is Behavioural Ecology Going?
Opinion TRENDS in Ecology and Evolution Vol.21 No.7 July 2006 Where is behavioural ecology going? Ian P.F. Owens Division of Biology and NERC Centre for Population Biology, Imperial College London, Silwood Park, Ascot, Berkshire, UK, SL5 7PY Since the 1990s, behavioural ecologists have largely wove together the theories developed over the preceding abandoned some traditional areas of interest, such as decade and championed a new empirical approach to optimal foraging, but many long-standing challenges investigating behaviour. The key element of this approach remain. Moreover, the core strengths of behavioural was the use of adaptation as the central conceptual ecology, including the use of simple adaptive models to framework, which gave behavioural ecologists a precise investigate complex biological phenomena, have now a priori expectation: behaviours should evolve to maxi- been applied to new puzzles outside behaviour. But this mise the fitness of the individuals showing strategy comes at a cost. Replication across studies is those behaviours. rare and there have been few tests of the underlying Krebs and Davies also stressed the importance of two genetic assumptions of adaptive models. Here, I attempt other principles [27]. The first was the need to quantify to identify the key outstanding questions in behavioural variation in behaviour accurately. Drawing attention to ecology and suggest that researchers must make the new quantitative work that was being performed in greater use of model organisms and evolutionary some areas of ethology [28,29], they showed how this genetics in order to make substantial progress on approach could be applied to a variety of behaviours. -
Competitive Exclusion Principle: What Ecology Can Teach Us About Solving
Competitive Exclusion Principle and the Partnership Conundrum: What ecology can teach us about solving conflicts and working together Sarah Low Philadelphia Field Station US Forest Service – Northern Research Station Objectives • Think differently about partnerships by applying management principles and ecological terms to inter-organizational dynamics • Focus on the role of competition in partnership success • Look at some examples of successful partnerships • Think about niches in light of our own partnerships Photo: Illinois Extension Photo: Leslie J. Mehrhoff, University of Connecticut, IPANE, http://invasives.eeb.uconn.edu/ipane/ • “Partnerships are important to us. I can’t reiterate that enough. We couldn’t do this alone. That said, we don’t like to compete for things like purchasing land.” – Anonymous, said at a project tour Hypothetical Tree Planting Example • Municipality is responsible for street trees • Community group wants to plant street trees • Philanthropic organization wants to fund the planting of trees Competitive Exclusion Principle • If two non-interbreeding populations occupy the same ecological niche and occupy the same geographic territory then one will eventually displace the other (Hardin, Science 1960) Competitive Forces • Competition for Profit - rivalry among existing competitors Competitive Forces • Potential Entrants - threat of new entrants Competitive Forces • Customers – bargaining power of buyers Competitive Forces • Suppliers - bargaining power of suppliers Competitive Forces • Substitute Products - -
Effects of Predation and Competition on the Population Applied Ecology 1997, 34, Dynamics of Tetvanychus Pacificus on Grapevines 8 78-8 8 8 R
Joirriicrl o/ Effects of predation and competition on the population Applied Ecology 1997, 34, dynamics of Tetvanychus pacificus on grapevines 8 78-8 8 8 R. HANNA, L.T. WILSON*, F.G. ZALOM and D.L. FLAHERTYt Deparlmeii~of Etiromology. Utiiversiry of’ California, Dacis, Californiu, USA Summary 1. The Pacific spider mite Tetranyhus pacificus and the Willamette spider mite Eot- etmnyclzus rvillamettei are herbivore pests of grapevines in California. The two spider mite species share a common and often effective phytoseiid predator, the Western orchard predatory mite Metaseiitlus occidentalis. It has been suggested that E. wil- lamettei may be beneficial in vineyards because it may have a negative impact on the more damaging T. pacijicus through their shared predator or through some form of interspecific competition. We conducted field and greenhouse experiments to deter- mine the relative effects of these interactions between the two herbivores on the population dynamics of T.pacijicus in ‘Thompson Seedless’ grape vineyards. We also used the field data to generate a functional relationship for the combined impact of E, willamettei and M. occidentalis on T. pacificus. 2. Predation and predator-mediated apparent competition were the only factors affecting T. pacificus densities in the field experiment. The addition of the predatory mite M. occidentalis alone resulted in a significant reduction in T. pacificus densities, while the addition of E. willamettei alone had little impact on T. pacificus densities. The greatest reductions in T. pacijicus densities occurred in plots where both the predatory mite M. occidentalis and E. willamettei were added. The predatory mite occurred earliest and increased at the greatest rate in plots where it was released along with E.