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21 resultados encontrados para: TEMA: Cadenas de alimentación (Ecología)
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- Artículo con arbitraje
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Food and feeding habits of Octopus insularis in the Veracruz Reef System National Park and confirmation of its presence in the southwest Gulf of Mexico
Rosas Luis, Rigoberto (autor) ; Jiménez Badillo, María de Lourdes (autora) ; Montoliu Elena, Lucía (autora) ; Morillo Velarde, Piedad S. (autora) ;
Contenido en: Marine Ecology Vol. 40, no. 1, e12535 (February 2019), p. 1-6 ISSN: 0173-9565
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Resumen en: Inglés |
Resumen en inglés

Octopuses are active predators that feed on a wide range of prey including crustaceans, fishes, and mollusks. They are important components of coral reef systems and support local and artisanal fisheries in the Gulf of México. Octopus insularis has been found to be one of the most relevant components in catches from the coral reef system of Veracruz in the southwestern Gulf of Mexico, and its role in the ecosystem requires assessment. To corroborate the morphological identification of O. insularis, six octopuses were identified by genetic methods. And to understand the trophic relationships between this octopus species and its prey, 394 octopuses caught during 2016 and 2017 by an artisanal fleet were sampled and their stomach contents analyzed. Results showed that crustaceans are the most frequently consumed group, with the genera Mithraculus and Etisus being the most important in the diet. Fishes, bivalves, and gastropods were identified as uncommon prey items in the diet. Their presence in the stomachs could be related to the movement of this octopus outside of the coral reef. Considering that our samples were of medium‐ and large‐sized individuals, cannibalism could be discarded for O. insularis in this size range in the Veracruz reef system. These findings suggest a generalist and opportunistic predation of O. insularis on the most abundant and available prey in the study area, namely the crustaceans. These represents an effective transfer of biomass from the low trophic levels to top predators in the coral reef system.

- Artículo con arbitraje
Resumen en: Inglés |
Resumen en inglés

Assessments of trophic diversity are critical for evaluating ecological integrity of habitats, but interpretations of such assessments require an understanding of variation across natural environmental gradients. This can be problematic when comparing structure of assemblages in under-studied regions or habitats, such as watersheds in dry tropical forests. Here,we compared assemblage-wide trophic metrics and intraspecific variation for a subset of consumer traits across rivers and among different ecosystem types within the Grijalva and Usumacinta River basins of Mexico. The two rivers differ with respect to flow-regime alteration and climate: the Grijalva River has been hydrologically altered by a series of dams and has wet and dry tropical forests in its watershed, whereas the Usumacinta River remains unimpounded with a watershed dominated by tropical wet forest. Use of allochthonous resourceswas pervasive in Usumacinta basin tributaries,with stable isotope signatures suggesting that many fishes directly consumed riparian plants and detritus. In contrast, fish assemblages inGrijalva basin tributaries were supported by higher proportions of in-stream production. Food-chain length was highest in a Grijalva River reservoir fish assemblage, although trophic diversity was lowin the impounded systemcompared to the mainstem Usumacinta River, where fishes consumed the broadest variety of food resources. We also observed differences in trophic ecology and body nutrient content within taxa across habitat types and basins. The differences we observed suggest that even in relatively intact watersheds, expectations for trophic structure in tropical streams should be adjusted based on factors such as discharge, climate, and riparian forest cover.

Trophic ecology / James E. Garvey, Matt R. Whiles
Garvey, James E. (autor) ; Whiles, Matt R. (autor) ;
Boca Raton, Florida, United States : CRC Press :: Taylor & Francis Group , c2017
Clasificación: 577.16 / G3
Bibliotecas: Tapachula
SIBE Tapachula
ECO020013875 (Disponible)
Disponibles para prestamo: 1
Índice | Resumen en: Inglés |
Resumen en inglés

This book is a bridge between ecological paradigms - organismal/community approaches to food web dynamics and ecosystem-level approaches to production. The unification of organismal, community, and ecosystem approaches in ecology is emerging due to the growing availability of new techniques for assessing trophic interactions and their implications for ecosystems. Trophic Ecology is a formal text for both newcomers to the discipline as well as seasoned professionals looking for new ideas and refreshers on old topics. A wide range of topics are explained including autotrophy, heterotrophy, omnivory, decomposition, foraging behavior and theory, trophic cascades, bioenergetics, and production. The audience is upper-level undergraduate students and entry-level graduate students interested in autecological, organismal approaches to ecology, community and ecosystem ecology. It is also a reference text for instructors teaching upper-division courses, providing examples from the literature, quantitative approaches to teach, and new hypotheses yet to be fully tested by ecologists.


Chapter 1. Introduction and History of Trophic Ecology Concepts and Patterns
Section I Concepts and Patterns
Chapter 2. Trophic Pyramids and Trophic Levels
Chapter 3. Scavenging and Decomposition Mechanisms at the organismal Scale
Section II Mechanisms at the Organismal Scale
Chapter 4. Foraging in Patches
Chapter 5. Predation
Chapter 6. Prey Diet Data, Modeling, and Energetics Approaches
Section III: Diet Data, Modeling, and Energetics Approaches
Chapter 7. Analyzing Diets
Chapter 8. Bioenergetics, Ecosystem Metabolism, and Metabolic Theory
Chapter 9. Consumption and Nutrition Community and ecosystem concepts
Section IV Community and Ecosystem Concepts
Chapter 10. Food Webs
Chapter 11. Secondary Production Quantifying Material Flux and Synthesis
Section V Quantifying Material Flux and Synthesis
Chapter 12. Nutrient Dynamics and Stoichiometry
Chapter 13. Elements and Isotopes as Tracers
Chapter 14. Use and Importance of Lipids in Trophic Ecology
Chapter 15. Synthesis for Trophic Ecology

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Differences in food web structure of mangroves and freshwater marshes: evidence from stable isotope studies in the Southern Gulf of Mexico
Sepúlveda Lozada, Alejandra ; Mendoza Carranza, Manuel (coaut.) ; Wolff, Matthias (coaut.) ; Saint Paul, Ulrich (coaut.) ; Ponce Mendoza, Alejandro (coaut.) ;
Contenido en: Wetlands Ecology and Management Vol. 23, no. 2 (April 2015), p. 293-314 ISSN: 1572-9834
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Resumen en: Inglés |
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Tropical coastal habitats like marshes, mangroves, and submerged grasses comprise diverse plant and animal communities and a certain degree of connectivity with other ecosystems. We compared the food web structure of a fringing mangrove-seagrass habitat and three fluvio-lagoons with marsh-eelgrass and mangrove-bare sediments during a dry season in Terminos Lagoon and Centla Wetlands, Southern Gulf of Mexico. Analysis of d13C and d15N stable isotopes in tissues of aquatic consumers, primary producers, and other carbon sources, in combination with isotope- based Bayesian methods, were performed to determine the main food sources and the isotopic niche of the consumers’ communities. Consumers in the man- grove-seagrass site showed high dependence on phytoplankton (average contribution 31 %), macroal- gae (20 %) and organic matter derived from seagrass- es (17 %). In the fluvio-lagoons, consumers showed high dependence on marginal vegetation (16–46 %). Phytoplankton and mangrove epiphytes comprised other important resources at these sites (with contri- butions of 24–44 %). The isotopic niche of consumers from the fringing mangrove-seagrass site did not overlap with those from the fluvio-lagoons. Moreover, despite the predominance of generalist consumers in all sites, differences in their isotopic niche area were observed, with consumers from the marsh-eelgrass site showing the narrowest. This suggests that con- sumer resource availability greatly differs in these habitats. Our results provide valuable information that help increase our understanding about the trophic structure in these important estuarine systems.

Trophic ecology: bottom-up and top-down interactions across aquatic and terrestrial systems / edited by Torrance C. Hanley, Kimberley J. La Pierre
Hanley, Torrance C. (ed.) (1979-) ; Pierre, Kimberley J. La (coed.) ;
Cambridge, CB : Cambridge University Press , c2015
Clasificación: 577.16 / T7
Bibliotecas: San Cristóbal
SIBE San Cristóbal
ECO010009327 (Disponible)
Disponibles para prestamo: 1
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As researchers try to predict the effects of human modification at all trophic levels and mediate the impact of rapid environmental change, it has become clear it is no longer a matter of agreeing that both bottom-up and top-down forces play important roles in diverse ecosystems. Rather, the question is: how do these forces interact across aquatic and terrestrial systems? Written by leading experts in the field, this book presents a unique synthesis of trophic relationships within and across ecosystems that is a valuable foundation for the development of cross-system, multidisciplinary research. It also provides new insights into population biology and community ecology and examines the interactive effects of bottom-up and top-down forces on biodiversity at each trophic level. A one-stop resource for learning about bottom-up and top-down interactions, this book encourages discussion and collaboration among researchers to identify similarities and differences in trophic interactions across aquatic and terrestrial systems.


List of contributors
Part I. Theory: 1. Theoretical perspectives on bottom-up and top-down interactions across ecosystems
Part II. Ecosystems
2. The spatio-temporal dynamics of trophic control in large marine ecosystems
3. Top-down and bottom-up interactions in freshwater ecosystems: emerging complexities
4. Top-down and bottom-up interactions determine tree and herbaceous layer dynamics in savannah grasslands
5. Bottom-up and top-down forces shaping wooded ecosystems: lessons from a cross-biome comparison
6. Dynamic systems of exchange link trophic dynamics in freshwater and terrestrial food webs
7. Bottom-up and top-down interactions in coastal interface systems
Part III. Patterns and Processes
8. Influence of plant defences and nutrients on trophic control of ecosystems
9. Interactive effects of plants, decomposers, herbivores, and predators on nutrient cycling
10. The role of bottom-up and top-down interactions in determining microbial and fungal diversity and function
11. The question of scale in trophic ecology
12. The role of species diversity in bottom-up and top-down interactions
13. Plant and herbivore evolution within the trophic sandwich
14. Bottom-up and top-down interactions across ecosystems in an era of global change

Food webs and biodiversity: foundations, models, data / Axel G. Rossberg
Rossberg, Axel G. (1969-) ;
Chichester, West Sussex, UK : Wiley Blackwell , 2013
Clasificación: 577.16 / R6
Bibliotecas: San Cristóbal
SIBE San Cristóbal
ECO010015852 (Disponible)
Disponibles para prestamo: 1
Índice | Resumen en: Inglés |
Resumen en inglés

Food webs have now been addressed in empirical and theoretical research for more than 50 years. Yet, even elementary foundational issues are still hotly debated. One difficulty is that a multitude of processes need to be taken into account to understand the patterns found empirically in the structure of food webs and communities. Food Webs and Biodiversity develops a fresh, comprehensive perspective on food webs. Mechanistic explanations for several known macroecological patterns are derived from a few fundamental concepts, which are quantitatively linked to field-observables. An argument is developed that food webs will often be the key to understanding patterns of biodiversity at community level. Key Features: Predicts generic characteristics of ecological communities in invasion-extirpation equilibrium. Generalizes the theory of competition to food webs with arbitrary topologies. Presents a new, testable quantitative theory for the mechanisms determining species richness in food webs, and other new results. Written by an internationally respected expert in the field. With global warming and other pressures on ecosystems rising, understanding and protecting biodiversity is a cause of international concern. This highly topical book will be of interest to a wide ranging audience, including not only graduate students and practitioners in community and conservation ecology but also the complex-systems research community as well as mathematicians and physicists interested in the theory of networks.


List of Symbols
Part I Preliminaries
1 Introduction
2 Models and Theories
2.1 The usefulness of models
2.2 What models should model
2.3 The possibility of ecological theory
2.4 Theory-driven ecological research
3 Some Basic Concepts
3.1 Basic concepts of food-web studies
3.2 Physical quantities and dimensions
Part II Elements of Food-Web Models
4 Energy and Biomass Budgets
4.1 Currencies of accounting
4.2 Rates and efficiencies
4.3 Energy budgets in food webs
5 Allometric Scaling Relationships Between Body Size and Physiological Rates
5.1 Scales and scaling
5.2 Allometric scaling
6 Population Dynamics
6.1 Basic considerations
6.1.1 Exponential population growth
6.1.2 Five complications
6.1.3 Environmental variability
6.2 Structured populations and density-dependence
6.2.1 The dilemma between species and stages
6.2.2 Explicitly stage-structured population dynamics
6.2.3 Communities of structured populations
6.3 The Quasi-Neutral Approximation
6.3.1 The emergence of food webs
6.3.2 Rana catesbeiana and its resources
6.3.3 Numerical test of the approximation
6.4 Reproductive value
6.4.1 The concept of reproductive value
6.4.2 The role of reproductive value in the QNA
6.4.3 Body mass as a proxy for reproductive value
7 From Trophic Interactions to Trophic Link Strengths
7.1 Functional and numerical responses
7.2 Three models for functional responses
7.2.1 Linear response
7.2.2 Type II response
7.2.3 Type II response with prey switching
7.2.4 Strengths and weaknesses of these models
7.3 Food webs as networks of trophic link strengths
7.3.1 The ontology of trophic link strengths
7.3.2 Variability of trophic link strengths
8 Tropic Niche Space and Trophic Traits
8.1 Topology and dimensionality of trophic niche space
8.1.1 Formal setting
8.1.2 Definition of trophic niche-space dimensionality

8.2 Examples and ecological interpretations
8.2.1 A minimal example
8.2.2 Is the definition of dimensionality reasonable?
8.2.3 Dependencies between vulnerability and foraging traits of a species
8.2.4 The range of phenotypes considered affects niche-space dimensionality
8.3 Determination of trophic niche-space dimensionality
8.3.1 Typical empirical data
8.3.2 Direct estimation of dimensionality
8.3.3 Iterative estimation of dimensionality
8.4 Identification of trophic traits
8.4.1 Formal setting
8.4.2 Dimensional reduction
8.5 The geometry of trophic niche space
8.5.1 Abstract trophic traits
8.5.2 Indeterminacy in abstract trophic traits
8.5.3 The D-dimensional niche space as a pseudo-Euclidean space
8.5.4 Linear transformations of abstract trophic traits
8.5.5 Non-linear transformations of abstract trophic traits
8.5.6 Standardization and interpretation of abstract trophic traits
8.5.7 A hypothesis and a convention
8.5.8 Getting oriented in trophic niche space
8.6 Conclusions
9 Community Turnover and Evolution
9.1 The spatial scale of interest
9.2 How communities evolve
9.3 The mutation-for-dispersion trick
9.4 Mutation-for-dispersion in a neutral food-web model
10 The Population-Dynamical Matching Model
Part III Mechanisms and Processes
11 Basic Characterizations of Link-Strength Distributions
11.1 Modelling the distribution of logarithmic link strengths
11.1.1 General normally distributed trophic traits
11.1.2 Isotropically distributed trophic traits
11.2 High-dimensional trophic niche spaces
11.2.1 Understanding link stengths in high-dimensional trophic niche spaces
11.2.2 Log-normal probability distributions
11.2.3 The limit of log-normally distributed trophic link strength
11.2.4 Correlations between trophic link strengths
11.2.5 The distribution of the strengths of observable links
11.2.6 The probability of observing links (connectance)

11.2.7 Estimation of link-strength spread and Pareto exponent
11.2.8 Empirical examples
12 Diet Partitioning
12.1 The diet partitioning function
12.1.1 Relation to the probability distribution of diet proportions
12.1.2 Another probabilistic interpretation of the DPF
12.1.3 The normalization property of the DPF
12.1.4 Empirical determination of the DPF
12.2 Modelling the DPF
12.2.1 Formal setting
12.2.2 Diet ratios
12.2.3 The DPF for high-dimensional trophic niche spaces
12.2.4 Gini-Simpson dietary diversity
12.2.5 Dependence of the DPF on niche-space dimensionality
12.3 Comparison with data
12.4 Conclusions
13 Multivariate Link-Strength Distributions and Phylogenetic Patterns
13.1 Modelling phylogenetic structure in trophic traits
13.1.1 Phylogenetic correlations among logarithmic link strengths
13.1.2 Phylogenetic correlations among link strengths
13.1.3 Phylogenetic patterns in binary food webs
13.2 The matching model
13.2.1 A simple model for phylogenetic structure in food webs
13.2.2 Definition of the matching model
13.2.3 Sampling steady-state matching model food webs
13.2.4 Alternatives to the matching model
13.3 Characteristics of phylogenetically structured food webs
13.3.1 Graphical representation of food-web topologies
13.3.2 Standard parameter values
13.3.3 Intervality
13.3.4 Intervality and trophic niche-space dimensionality
13.3.5 Degree distributions
13.3.6 Other phylogenetic patterns
13.3.7 Is phylogeny just a nuisance?
14 A Framework Theory for Community Assembly
14.1 Ecological communities as dynamical systems
14.2 Existence, positivity, stability, and permanence
14.3 Generic bifurcations in community dynamics and their ecological phenomenology
14.3.1 General concepts
14.3.2 Saddle-node bifurcations
14.3.3 Hopf bifurcations
14.3.4 Transcritical bifurcations
14.3.5 Bifurcations of complicated attractors

14.4 Comparison with observations
14.4.1 Extirpations and invasions proceed slowly
14.4.2 The logistic equation works quite well
14.4.3 IUCN Red-List criteria highlight specific extinction scenarios
14.4.4 Conclusion
14.5 Invasion fitness and harvesting resistance
14.5.1 Invasion fitness
14.5.2 Harvesting resistance: definition
14.5.3 Harvesting resistance: interpretation
14.5.4 Harvesting resistance: computation
14.5.5 Interpretation of h → 0
14.6 Community assembly and stochastic species packing
14.6.1 Community saturation and species packing
14.6.2 Invasion probability
14.6.3 The steady-state distribution of harvesting resistance
14.6.4 The scenario of stochastic species packing
14.6.5 A numerical example
14.6.6 Biodiversity and ecosystem functioning
15 Competition in Food Webs
15.1 Basic concepts
15.1.1 Modes of competition
15.1.2 Interactions in communities
15.2 Competition in two-level food webs
15.2.1 The Lotka-Volterra two-level food-web model
15.2.2 Computation of the equilibrium point
15.2.3 Direct competition among producers
15.2.4 Resource-mediated competition in two-level food webs
15.2.5 Consumer-mediated competition in two-level food webs
15.3 Competition in arbitrary food webs
15.3.1 The general Lotka-Volterra food-web model
15.3.2 The competition matrix for general food webs
15.3.3 The L-R-P formalism
15.3.4 Ecological interpretations of the matrices L, R, and P
15.3.5 Formal computation of the equilibrium point
15.3.6 Consumer-mediated competition in general food webs
15.3.7 Consumer-mediated competitive exclusion
15.3.8 Conclusions
16 Mean-Field Theory of Resource-Mediated Competition
16.1 Transition to scaled variables
16.1.1 The competitive overlap matrix
16.1.2 Free abundances
16.2 The extended mean-field theory of competitive exclusion
16.2.1 Assumptions
16.2.2 Separation of means and residuals

16.2.3 Mean-field theory for the mean scaled abundance
16.2.4 Mean-field theory for the variance of scaled abundance
16.2.5 The coefficient of variation of scaled abundance
16.2.6 Related theories
17 Resource-Mediated Competition and Assembly
17.1 Preparation
17.1.1 Scaled vs. unscaled variables and parameters
17.1.2 Mean-field vs framework theory
17.2 Stochastic species packing under asymmetric competition
17.2.1 Species richness and distribution of invasion fitness (Part I)
17.2.2 Community response to invasion
17.2.3 Sensitivity of residents to invaders
17.2.4 Species richness and distribution of invasion fitness (Part II)
17.2.5 Random walks of abundances driven by invasions
17.2.6 Further discussion of the scenario
17.3 Stochastic species packing with competition symmetry
17.3.1 Community assembly with perfectly symmetric competition
17.3.2 Community assembly under nearly perfectly symmetric competition
17.3.3 Outline of mechanism limiting competition avoidance
17.3.4 The distribution of invasion fitness
17.3.5 Competition between residents and invaders
17.3.6 Balance of scaled biomass during assembly
17.3.7 Competition avoidance
17.3.8 Numerical test of the theory
18 Random-Matrix Competition Theory
18.1 Asymmetric competition
18.1.1 Girko’s Law
18.1.2 Application to competitive overlap matrices
18.1.3 Implications for sensitivity to invaders
18.1.4 Relation to mean-field theory
18.2 Stability vs feasibility limits to species richness
18.2.1 The result of May (1972)
18.2.2 Comparison of stability and feasibility criteria
18.3 Partially and fully symmetric competition
18.4 Sparse overlap matrices
18.4.1 Sparse competition
18.4.2 Eigenvalue distributions for sparse matrices
18.5 Resource overlap matrices
18.5.1 Diffuse resource competition
18.5.2 Sparse resource competition: the basic problem
18.5.3 The effect of trophic niche-space geometry

18.5.4 Competition among highly specialized consumers
18.5.5 Resource competition for varying ratios of producer to consumer richness
18.5.6 Competition for competing resources
18.6 Comparison with data
18.6.1 Gall-inducing insects on plants
18.6.2 Freshwater ecosystems
18.6.3 The North Sea
18.6.4 Conclusions
19 Species Richness, Size and Trophic Level
19.1 Predator-prey mass ratios
19.2 Modelling the joint distribution of size, trophic level, and species richness
19.2.1 Initial considerations
19.2.2 Model definition
19.2.3 Model simulation and comparison with data
20 Consumer-Mediated Competition and Assembly
20.1 A two-level food-web assembly model
20.2 Analytic characterization of the model steady state
20.2.1 Mechanism controlling producer richness
20.2.2 Other characteristics of the model steady state
20.3 Dependence of invader impacts on dietary diversity
20.3.1 Formal setting
20.3.2 Invadibility condition
20.3.3 Extirpation of resources during invasion
20.3.4 Extirpation of resources through consumer-mediated competition
20.3.5 Synthesis
20.4 Evolution of base attack rates
20.4.1 Motivation
20.4.2 Model definition
20.4.3 Numerical demonstration of attack rate evolution
20.4.4 Attack-rate evolution and prudent predation
21 Food Chains and Size Spectra
21.1 Concepts
21.1.1 Community size spectra
21.1.2 Species size spectra
21.2 Power-law food chains
21.2.1 Infinitely long power-law food chains
21.2.2 Top-down and bottom-up control
21.2.3 Power law-food chains of finite lengths and their stability to pulse perturbations
21.2.4 Food chains as approximations for size spectra
21.2.5 Adaptation of attack rates
21.3 Food chains with non-linear functional responses
21.3.1 Loss of stability with density-independent consumption
21.3.2 Linearization of a generalized food chain model
21.3.3 Linear responses to press perturbations

21.3.4 Linear stability to pulse perturbations
21.4 What are the mechanisms controlling the scaling laws?
21.4.1 Arguments for biological constraints on transfer efficiency
21.4.2 Arguments for stability constraints on transfer efficiency
21.4.3 Arguments for ecological constraints on biomass imbalance
21.4.4 Arguments for mechanical constraints on PPMR
21.4.5 Arguments for dynamical constraints on PPMR
21.4.6 Conclusions
21.5 Scavengers and detrivores
21.5.1 The general argument
21.5.2 The microbial loop and other detrital channels
22 Structure and Dynamics of PDMM Model Communities
22.1 PDMM model definition
22.1.1 Model states
22.1.2 Species sampling and community assembly
22.1.3 Population dynamics
22.2 PDMM simulations
22.2.1 Trophic niche space and phylogenetic correlations
22.2.2 Steady state and invasion fitness
22.2.3 Diet partitioning
22.2.4 Resource-mediated competition
22.2.5 Distribution of species over body sizes and trophic levels
22.2.6 The size spectrum and related distributions
22.3 The PDMM with evolving attack rates
22.3.1 Modelling and tracking evolving attack rates in the PDMM
22.3.2 Time series of species richness, aggressivity and dietary diversity
22.3.3 Mutual regulation of aggressivity and dietary diversity
22.4 Conclusions
Part IV Implications
23 Scientific Implications
23.1 Main mechanisms identified by the theory
23.1.1 Two trades – one currency
23.1.2 Resource-mediated competition
23.1.3 Randomness and structure in food webs
23.1.4 Consumer-mediated competition and attack-rate evolution
23.2 Testable assumptions and predictions
23.2.1 Link-strength distributions and trophic niche-space geometry
23.2.2 Diet-partitioning statistics and sampling curves
23.2.3 Prey switching
23.2.4 Adapted attack rates
23.2.5 Community assembly and turnover
23.2.6 Patterns in link-strength matrices
23.3 Some unsolved problems

23.3.1 Large plants
23.3.2 Interactions between modes of competition
23.3.3 Absolute species richness: the role of viruses
23.3.4 The role of prey switching for community structure
23.3.5 The role of phylogenetic correlations for community dynamics
23.3.6 Fundamental constraints determining size-spectrum slopes
23.3.7 Community assembly with non-trivial attractors
23.3.8 Solution of the Riccati Equation for resource competition
23.3.9 Eigenvalues of competition matrices
23.3.10 Geometry and topology of trophic niche space
23.4 The future of community ecology
24 Conservation Implications
24.1 Assessing biodiversity
24.1.1 Quantifying biodiversity
24.1.2 Biodiversity supporting biodiversity
24.1.3 Assessing community turnover
24.2 Modelling ecological communities
24.2.1 Unpredictability of long-term community responses
24.2.2 Short-term predictions of community responses
24.2.3 Coarse-grained and stochastic community models
24.3 Managing biodiversity
Appendix A
A.1 Mathematical concepts, formulae, and jargon
A.1.1 Sums
A.1.2 Complex numbers
A.1.3 Vectors and matrices
A.1.4 Sets and functions
A.1.5 Differential calculus
A.1.6 Integrals
A.1.7 Differential equations
A.1.8 Random variables and expectation values

*En hemeroteca, SIBE-San Cristóbal
Hydrogen sulfide, bacteria, and fish: a unique, subterranean food chain
Roach, Katherine A. ; Tobler, Michael (coaut.) ; Winemiller, Kirk O. (coaut.) ;
Contenido en: Ecology Vol. 93, no. 11 (November 2011), p. 2056-2062 ISSN: 0012-9658
Bibliotecas: San Cristóbal
SIBE San Cristóbal
51055-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

Photoautotrophs are generally considered to be the base of food webs, and habitats that lack light, such as caves, frequently rely on surface-derived carbon. Here we show, based on analysis of gut contents and stable isotope ratios of tissues (13C/12C and 15N/14N), that sulfur-oxidizing bacteria are directly consumed and assimilated by the fish Poecilia mexicana in a sulfide-rich cave stream in Tabasco state, Mexico. Our results provide evidence of a vertebrate deriving most of its organic carbon and nitrogen from in situ chemoautotrophic production, and reveals the importance of alternative energy production sources supporting animals in extreme environments.


- Artículo con arbitraje
Aquatic food webs in mangrove and seagrass habitats of Centla Wetland, a Biosphere Reserve in Southeastern Mexico
Mendoza Carranza, Manuel ; Hoeinghaus, David J. (coaut.) ; Garcia, Alexandre M. (coaut.) ; Romero Rodríguez, Ángel (coaut.) ;
Contenido en: Neotropical Ichthyology Vol. 8, no. 1 (2010), p. 171-178 ISSN: 1982-0224
Resumen en: Inglés | Portugués |
Resumen en inglés

Mangrove and seagrass habitats are important components of tropical coastal zones worldwide, and are conspicuous habitats of Centla Wetland Biosphere Reserve (CWBR) in Tabasco, Mexico. In this study, we examine food webs in mangrove- and seagrass-dominated habitats of CWBR using stable isotope ratios of carbon and nitrogen. Our objective was to identify the importance of carbon derived from mangroves and seagrasses to secondary production of aquatic consumers in this poorly studied conservation area. Carbon and nitrogen isotope ratios of basal sources and aquatic consumers indicated that the species-rich food webs of both habitats are dependent on riparian production sources. The abundant Red mangrove Rhizophora mangle appears to be a primary source of carbon for the mangrove creek food web. Even though dense seagrass beds were ubiquitous, most consumers in the lagoon food web appeared to rely on carbon derived from riparian vegetation (e.g. Phragmites australis). The introduced Amazon sailfin catfish Pterygoplichthys pardalis had isotope signatures overlapping with native species (including high-value fisheries species), suggesting potential competition for resources. Future research should examine the role played by terrestrial insects in linking riparian and aquatic food webs, and impacts of the expanding P. pardalis population on ecosystem function and fisheries in CWBR. Our findings can be used as a baseline to reinforce the conservation and management of this important reserve in the face of diverse external and internal human impacts.

Resumen en portugués

Manguezais e pradarias de gramíneas são importantes componentes das zonas costeiras tropicais em todo o mundo, sendo habitats comuns nos “Pântanos de Centla”, uma Reserva da Biosfera localizada em Tabasco, México. Nesse trabalho, são investigadas as teias alimentares de habitats dominados por manguezais e pradarias de gramíneas, através de isótopos estáveis de carbono e nitrogênio, tendo como objetivo identificar a importância do carbono derivado desses produtores para a produção aquática secundária nessa unidade de conservação tão pouco estudada. As razões isotópicas de carbono e nitrogênio das fontes basais e dos consumidores aquáticos indicam que as teias alimentares, ricas em espécies, de ambos os habitats, são dependentes da produção ripária. O abundante mangue-vermelho Rhizophora mangle parece ser a fonte primária de carbono no habitat dominado por manguezais. Em contraste, muito embora as pradarias de gramíneas sejam conspícuas no ambiente lagunar estudado, muitos dos consumidores da teia alimentar nessa região parecem depender do carbono oriundo da vegetação ripária (e.g. Phragmites australis). A espécie de bagre exótica Pterygoplichthys pardalis possui assinaturas isotópicas que se sobrepõem a das espécies nativas (incluindo algumas de elevado valor comercial na pesca), sugerindo competição potencial por recursos. Novas investigações deveriam avaliar o papel dos insetos terrestres como elo de conexão entre as teias alimentares da mata ripária e do ambiente aquático, bem como os impactos da expansão da população de P. pardalis sobre o funcionamento do ecossistema e das pescarias no “Pântano de Centla”. Considerando os múltiplos impactos antrópicos na região, os resultados obtidos no presente trabalho podem ser utilizados como uma base de referência em programas de gerenciamento e conservação da diversidade nessa importante Reserva da Biosfera.

The Near Threatened bearded screech-owl Megascops barbarus: diet pattern and trophic assessment using δ13C and δ15N stable-isotopes
Enríquez Rocha, Paula Lidia ; Cheng, Kimberly M. (coaut.) ; Elliott, Jhon E. (coaut.) ;
Contenido en: Bird Conservation International Vol. 20, no. 1 (2010), p. 1-9 ISSN: 0959-2709
Resumen en: Inglés |
Resumen en inglés

The diet patterns and trophic relationships are poorly understood for most tropical owl species. We used stable isotopes of carbon (d13C) and nitrogen (d15N) in 24 feather samples of the rare, endemic, and ‘Near Threatened’ Bearded Screech-owl Megascops barbarus to determine the trophic level of their prey and evaluate whether diet patterns vary (1) among individuals, (2) spatially along the species’s range in the highlands of Chiapas, Mexico, and (3) temporally during the short- and long-term. Our results indicated that there was diet variation among individuals during the period of feather growth and there was a high positive correlation between stable isotopes in body and rectrices. The stable isotopes showed significant temporal differences in d15N signature values, but not in d13C values, with no obviously interpretable temporal pattern. Spatially, values of d13C and d15N did not vary across all nine sampled locations. The observed lower d13C values suggested that this owl lives in humid forests. More long-term studies and spatial dietary and prey analysis will be necessary to increase our understanding of how habitat conditions determine the distribution, abundance and quality of food for the Bearded Screech-owl