Comparing isotopic niche widths among and within communities: SIBER - Stable Isotope Bayesian Ellipses in R

Journal of Animal Ecology, Journal Year: 2011, Volume and Issue: 80(3), P. 595 - 602

Published: March 14, 2011

1. The use of stable isotope data to infer characteristics community structure and niche width members has become increasingly common. Although these developments have provided ecologists with new perspectives, their full impact been hampered by an inability statistically compare individual communities using descriptive metrics. 2. We solve issues reformulating the metrics in a Bayesian framework. This reformulation takes account uncertainty sampled naturally incorporates error arising from sampling process, propagating it through derived 3. Furthermore, we develop novel multivariate ellipse-based as alternative currently employed Convex Hull methods when applied single members. show that unlike Hulls, ellipses are unbiased respect sample size, estimation via inference allows robust comparison be made among sets comprising different sizes. 4. These metrics, which call SIBER (Stable Isotope Ellipses R), open up more avenues for direct isotopic niches across communities. computational code calculate is implemented free-to-download package Stable Analysis R statistical environment.

Language: Английский

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CAN STABLE ISOTOPE RATIOS PROVIDE FOR COMMUNITY-WIDE MEASURES OF TROPHIC STRUCTURE?

Ecology, Journal Year: 2007, Volume and Issue: 88(1), P. 42 - 48

Published: Jan. 1, 2007

Stable isotope ratios (typically of carbon and nitrogen) provide one representation an organism's trophic niche are widely used to examine aspects food web structure. Yet stable isotopes have not been applied quantitatively characterize community-wide structure (i.e., at the level entire web). We propose quantitative metrics that can be this end, drawing on similar approaches from ecomorphology research. For example, convex hull area occupied by species in δ13C–δ15N space is a total extent diversity within web, whereas mean nearest neighbor distance among all pairs measure packing space. To facilitate discussion opportunities limitations metrics, we empirical conceptual examples drawn Bahamian tidal creek webs. These illustrate how methodology quantify redundancy webs, as well link individual characteristics which they embedded. Building extensive applications ecologists, may new perspective structure, function, dynamics.

Language: Английский

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Incorporating uncertainty and prior information into stable isotope mixing models

Ecology Letters, Journal Year: 2008, Volume and Issue: 11(5), P. 470 - 480

Published: Feb. 21, 2008

Abstract Stable isotopes are a powerful tool for ecologists, often used to assess contributions of different sources mixture (e.g. prey consumer). Mixing models use stable isotope data estimate the contribution mixture. Uncertainty associated with mixing is substantial, but has not yet been fully incorporated in models. We developed Bayesian‐mixing model that estimates probability distributions source while explicitly accounting uncertainty multiple sources, fractionation and signatures. This also allows optional incorporation informative prior information analyses. demonstrate our using predator–prey case study. Accounting inputs can change variability, magnitude rank order (source) predator (mixture). Isotope need account accurately contributions.

Language: Английский

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Applying stable isotopes to examine food‐web structure: an overview of analytical tools

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2011, Volume and Issue: 87(3), P. 545 - 562

Published: Nov. 2, 2011

Stable isotope analysis has emerged as one of the primary means for examining structure and dynamics food webs, numerous analytical approaches are now commonly used in field. Techniques range from simple, qualitative inferences based on isotopic niche, to Bayesian mixing models that can be characterize food‐web at multiple hierarchical levels. We provide a comprehensive review these techniques, thus single reference source help identify most useful apply given data set. around four general questions: (1) what is trophic position an organism web?; (2) which resource pools support consumers?; (3) additional information does relative consumers space reveal about structure?; (4) degree variability intrapopulation level? For each question, we detail different have been applied, discussing strengths weaknesses each. conclude with set suggestions transcend individual approaches, guidance future applications

Language: Английский

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The ecological causes of individual specialisation

Ecology Letters, Journal Year: 2011, Volume and Issue: 14(9), P. 948 - 958

Published: July 26, 2011

Ecology Letters (2011) 14 : 948–958 Abstract Many generalist populations are composed of specialised individuals, whose niches small subsets the population niche. This ‘individual specialisation’ is a widespread phenomenon in natural populations, but until recently few studies quantified magnitude individual specialisation and how this varies among or contexts. Such quantitative approaches necessary for us to understand ecological interactions influence amount among‐individual variation, variation might affect dynamics. Herein, we review recent specialisation, emphasising novel insights arising from measures diet variation. Experimental comparative have confirmed long‐standing theoretical expectations that depends on level intra interspecific competition, opportunity predation. In contrast, there little empirical information as affects community We discuss some emerging methodological issues guidelines researchers studying make specific recommendations regarding avenues future research.

Language: Английский

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Integrating food web diversity, structure and stability

Trends in Ecology & Evolution, Journal Year: 2011, Volume and Issue: 27(1), P. 40 - 46

Published: Sept. 24, 2011

Language: Английский

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Population-Level Metrics of Trophic Structure Based on Stable Isotopes and Their Application to Invasion Ecology

PLoS ONE, Journal Year: 2012, Volume and Issue: 7(2), P. e31757 - e31757

Published: Feb. 21, 2012

Biological invasions are a significant driver of human-induced global change and many ecosystems sustain sympatric invaders. Interactions occurring among these invaders have important implications for ecosystem structure functioning, yet they poorly understood. Here we apply newly developed metrics derived from stable isotope data to provide quantitative measures trophic diversity within populations or species. We then use test the hypothesis that belonging same functional feeding group occupy smaller isotopic niche than their allopatric counterparts. Two introduced, globally important, benthic omnivores, Louisiana swamp crayfish (Procambarus clarkii) carp (Cyprinus carpio), in Lake Naivasha, Kenya. applied our an 8-year set encompassing establishment lake. found strong asymmetric interaction between two invasive populations, as indicated by inverse correlations abundance diversity. Lack overlap majority years predominantly indirect interaction. suggest carp-induced habitat alteration reduced prey, resulting reduction dietary crayfish. Stable isotopes integrated signal diet over space time, offering appropriate scale study population niches, but few studies retained often insightful information revealed variability individuals values. Our incorporate such variation, robust vagaries sample size useful additional tool reveal subtle interactions Although demonstrated applicability specifically using detailed temporal dataset species invasion lake, wide array potential ecological applications.

Language: Английский

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Effectiveness monitoring of fish passage facilities: historical trends, geographic patterns and future directions

Fish and Fisheries, Journal Year: 2009, Volume and Issue: 11(1), P. 12 - 33

Published: May 18, 2009

Abstract Fishways and other passage facilities frequently prevent or delay the of fishes, highlighting need for effectiveness monitoring. We reviewed scientific literature from 1960 to 2008 reporting on monitoring fish assess what taxa life‐stages have been studied, questions that are asked during evaluation, how these varied over time by geographic region. identified 96 peer‐reviewed articles which 68% focused adult fishes. Salmoniformes was most studied order (58% studies). The focus fishway evaluations did not change years, but significantly Studies tropics had a broader taxonomic scope than studies temperate locations. Exogenous mechanisms failure, such as environmental, structural behavioural factors, were in 90% North America only ∼50% Europe, South Australia. Endogenous (i.e. physiological) affecting success often assessed anywhere, though they powerful means evaluating failure. Few monitored migration after left facility. To improve facilities, we suggest both endogenous exogenous be an integrated fashion understand failure inform design operational changes could efficiency. In addition post‐departure is required more completely fitness consequences passage.

Language: Английский

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Native predators and exotic prey –an acquired taste?

Frontiers in Ecology and the Environment, Journal Year: 2009, Volume and Issue: 7(10), P. 525 - 532

Published: Feb. 18, 2009

Only a small proportion of exotic species invasions give rise to hyper‐successful nuisance species, but those that do have dramatic negative impacts on ecosystems, such as the displacement native and disruption food webs. For predator, changes may mean major transformation in its resource base decline fitness. However, predators adapt become more effective at feeding prey, either rapidly, via existing phenotypic plasticity, or slowly, natural selection. Despite rapidly growing number publications importance driver contemporary evolution both invading we know little about how arrival prey affects predators. We propose could be important regulating long‐term dynamics and, consequently, overexploitation facilitate biological invasions.

Language: Английский

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Predicting rates of isotopic turnover across the animal kingdom: a synthesis of existing data

Journal of Animal Ecology, Journal Year: 2014, Volume and Issue: 84(3), P. 861 - 870

Published: Dec. 9, 2014

The stable isotopes of carbon ((12)C, (13)C) and nitrogen ((14)N, (15)N) represent powerful tools in food web ecology, providing a wide range dietary information animal consumers. However, identifying the temporal window over which consumer's isotopic signature reflects its diet requires an understanding elemental incorporation, process that varies from days to years across species tissue types. Though theory predicts body size temperature are likely control incorporation rates, this has not been tested empirically morphologically phylogenetically diverse taxa. Readily available estimates relationship would, however, aid design isotope investigations improve interpretation data collected natural systems. Using literature-derived turnover ranging 1 mg 2000 kg, we develop predictive tool for ecologists, allowing estimation rates structural tissues entirely novel In keeping with metabolic scaling theory, show whole organisms muscle scale allometrically mass raised approximately power -0.19, effect modulated by temperature. This did not, apply splanchnic tissues, were instead dependent on thermoregulation tactic employed organism, being considerably faster endotherms than ectotherms. We believe equations provide can experiments results obtained future studies.

Language: Английский

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