Biology subjects

Romero, G. Q.

Publications and source records attributed to Romero, G. Q..

3 recordsLinked to original sources

bioRxiv2024

Body size is a better predictor of intra- than interspecific variation of animal stoichiometry across realms

Animal stoichiometry affects fundamental processes ranging from organismal physiology to global element cycles. However, it is unknown whether animal stoichiometry follows predictable scaling relationships with body mass and whether adaptation to life on land or water constrains patterns of elemental allocation. To test both interspecific and intraspecific body-size scaling relationships of the nitrogen (N), phosphorus (P), and N:P content of animals, we used a subset of the StoichLife database encompassing 9,933 individual animals (vertebrates and invertebrates) belonging to 1,543 species spanning 10 orders of magnitude of body size from terrestrial, freshwater, and marine realms. Across species, body mass did not explain much variation in %N and %P composition, although the %P of invertebrates decreased with size. The effects of body size on species elemental content were small in comparison to the effects of taxonomy. Body size was a better predictor of intraspecific than interspecific elemental patterns. Between 42 to 45% in intraspecific stoichiometric variation was explained by body size for 27% of vertebrate species and 35% of invertebrate species. Further, differences between organisms inhabiting aquatic and terrestrial realms were observed only in invertebrate interspecific %N, suggesting that the realm does not play an important role in determining elemental allocation of animals. Based on our analysis of the most comprehensive animal stoichiometry database, we conclude that (i) both body size and realm are relatively weak predictors of animal stoichiometry across taxa, and (ii) body size is a good predictor of intraspecific variation in animal elemental content, which is consistent with tissue-scaling relationships that hold broadly across large groups of animals. This research reveals a lack of general scaling patterns in the elemental content across animals and instead points to a large variation in scaling relationships within and among lineages.

ecology↗

bioRxiv2020

Climate influences the response of community functional traits to local conditions

Functional traits determine an organisms performance in a given environment and as such determine which organisms will be found where. Species respond to local conditions, but also to larger scale gradients, such as climate. Trait ecology links these responses of species to community composition and species distributions. Yet, we often do not know which environmental gradients are most important in determining community trait composition at either local or biogeographical scales, or their interaction. Here we quantify the relative contribution of local and climatic conditions to the structure and composition of functional traits found within bromeliad invertebrate communities. We conclude that climate explains more variation in invertebrate trait composition within bromeliads than does local conditions. Importantly, climate mediated the response of traits to local conditions; for example, invertebrates with benthic life-history traits increased with bromeliad water volume only under certain precipitation regimes. Our ability to detect this and other patterns hinged on the compilation of multiple fine-grained datasets, allowing us to contrast the effect of climate vs. local conditions. We suggest that, in addition to sampling communities at local scales, we need to aggregate studies that span large ranges in climate variation in order to fully understand trait filtering at local, regional and global scales.

ecology↗

bioRxiv2016

Predator phylogenetic diversity decreases predation rate via antagonistic interactions

BackgroundPredator assemblages can differ substantially in their top-down effects on community composition and ecosystem function, but few studies have sought to explain this variation in terms of the phylogenetic distance between predators. The effect of a local predator assemblage will depend on three things - which predators tend to co-occur, how similar their prey preferences are, and how they interact with each other and the whole community. Phylogenetic distance between predators may correlate with each of these processes, either because related predators are more likely to share the same traits, and therefore have similar habitat and prey preferences, or because predators are more likely to compete, and therefore diverge in habitat and prey preferences. Therefore, the phylogenetic structure of predator assemblages could provide a unifying framework for predicting how predators will impact their prey - and therefore any ecosystem functions mediated by their prey.\n\nMethodsWe examined the effects of predators on macroinvertebrate food webs found in bromeliads, combining field observations, laboratory feeding trials and a manipulative experiment. We determined whether the phylogenetic distance between predators could explain: the co-observed occurrence of predator species among bromeliads, overlap in prey preferences under no-choice conditions, and effects of predator composition on prey survival, prey composition and ecosystem processes.\n\nResultsWe found that phylogenetic distance does not predict either the co-occurrence of predator species nor the overlap in their prey preferences. However, our manipulative experiment showed that prey mortality decreased as the phylogenetic distance between predator species increased, reflecting antagonistic interactions among more distant predators. These effects of phylogenetic distance on prey mortality did not translate into effects on ecosystem function, as measured by rates of detrital decomposition and nitrogen cycling.\n\nDiscussionWe conclude that the effects of predator phylogenetic diversity on the bromeliad food web are primarily determined by antagonistic predator-predator interac-tions, rather than habitat distribution or diet overlap. This study illustrates the potential of a phylogenetic community approach to understanding food webs dynamics.

ecology↗