Determinants of Density–Body Size Scaling Within Food Webs and Tools for Their Detection

Arim, Matı́as; Berazategui, Mauro; Barreneche, Juan Manuel; Ziegler, Lucía; Zarucki, Matías; Abades, Sebastián

doi:10.1016/b978-0-12-386475-8.00001-0

Cited by 44 publications

(51 citation statements)

References 134 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…10; table 1). Indeed, large and small mammals had almost zero probability of being carnivorous, as expected due to gape and energy limitations [9] and also consistent with the empirical evidence for modern faunas [4,6,10,23]. Theoretically, given that metabolic rate scales with body size at a power of approximately 0.75 and a trophic transfer efficiency between 1% and 40%, the predicted slope of the transition at large sizes between carnivores and non-carnivores 3), representing the transition from carnivorous to non-carnivorous, was consistent with theoretical expectations [9,10].…”

Section: Resultssupporting

confidence: 61%

“…The extensively documented body size hierarchy in trophic relationships [3], with large animals consuming small ones, determines systematic trends, such as increase in the number of prey and reduced predation risk [4][5][6], the ability to feed in various local communities [7], the integration of different energy channels [8] and the trends in trophic position [9,10]. The central role of body size on food web structure sheds light on the processes that moulded extinct faunas, in which community size structure strongly departed from contemporary examples [11], even though ancient and modern faunas share remarkable similarities [12].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Exceptional body sizes but typical trophic structure in a Pleistocene food web

2016

Self Cite

View full text Add to dashboard Cite

In this study, we focused on the exceptionally large mammals inhabiting the Americas during the Quaternary period and the paramount role of body size in species ecology. We evaluated two main features of Pleistocene food webs: the relationship between body size and (i) trophic position and (ii) vulnerability to predation. Despite the large range of species sizes, we found a hump-shaped relationship between trophic position and body size. We also found a negative trend in species vulnerability similar to that observed in modern faunas. The largest species lived near the boundary of energetic constraints, such that any shift in resource availability could drive these species to extinction. Our results reinforce several features of megafauna ecology: (i) the negative relationship between trophic position and body size implies that large-sized species were particularly vulnerable to changes in energetic support; (ii) living close to energetic imbalance could favour the incorporation of additional energy sources, for example, a transition from a herbivorous to a scavenging diet in the largest species (e.g. Megatherium ) and (iii) the interactions and structure of Quaternary megafauna communities were shaped by similar forces to those shaping modern fauna communities.

show abstract

Section: Resultssupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Exceptional body sizes but typical trophic structure in a Pleistocene food web

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Newman ; Edwards ; White, Enquist & Green ) and used (together with other methods) by Arim et al . () on body‐size data from ponds in Uruguay. The bounded power‐law distribution was recently used by Robinson & Baum () to analyse visual‐census data from coral‐reef fish communities around Kiritimati (Christmas Island).…”

Section: Resultsmentioning

confidence: 99%

Testing and recommending methods for fitting size spectra to data

et al. 2016

View full text Add to dashboard Cite

Summary1. The size spectrum of an ecological community characterizes how a property, such as abundance or biomass, varies with body size. Size spectra are often used as ecosystem indicators of marine systems. They have been fitted to data from various sources, including groundfish trawl surveys, visual surveys of fish in kelp forests and coral reefs, sediment samples of benthic invertebrates and satellite remote sensing of chlorophyll. 2. Over the past decades, several methods have been used to fit size spectra to data. We document eight such methods, demonstrating their commonalities and differences. Seven methods use linear regression (of which six require binning of data), while the eighth uses maximum likelihood estimation. We test the accuracy of the methods on simulated data. 3. We demonstrate that estimated size-spectrum slopes are not always comparable between the seven regressionbased methods because such methods are not estimating the same parameter. We find that four of the eight tested methods can sometimes give reasonably accurate estimates of the exponent of the individual size distribution (which is related to the slope of the size spectrum). However, sensitivity analyses find that maximum likelihood estimation is the only method that is consistently accurate, and the only one that yields reliable confidence intervals for the exponent. 4. We therefore recommend the use of maximum likelihood estimation when fitting size spectra. To facilitate this, we provide documented R code for fitting and plotting results. This should provide consistency in future studies and improve the quality of any resulting advice to ecosystem managers. In particular, the calculation of reliable confidence intervals will allow proper consideration of uncertainty when making management decisions.

show abstract

“…Body size is an important driver of structure and dynamics in many food webs (Arim et al, 2011;Melián et al, 2011;Nakazawa et al, 2011), especially in aquatic ecosystems Woodward et al, 2005), and can give rise to substructures, such as feeding hierarchies arising from gape-limited predation (Petchey et al, 2008;Woodward et al, 2010b). Recent explorations of so-called trivariate webs, in which feeding links are overlaid on mass-abundance plots, in marine , freshwater (Jonsson et al, 2005;Layer et al, 2010;Woodward et al, 2012) and terrestrial (McLaughlin et al, 2010;Mulder et al, 2011) systems have revealed strong size structure.…”

Section: Body Size As a Driver Of Ecological Network Structurementioning

confidence: 99%