ORCID Profile
0000-0001-7334-0434
Current Organisation
Trinity College Dublin
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Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-07-2013
Abstract: Bats, bees, seals, and many seabirds practice central-place foraging, leaving a central home site, such as a hive or a rookery, to forage in a specific territory. Such species also share the challenge of competing for local resources with in iduals from separate colonies. Using satellite tags, Wakefield et al. (p. 68 , published online 6 June see the Perspective by Weimerskirch ) followed over 180 northern gannets to determine potential drivers of foraging territory ision. Boundaries among colonial territories arose as a result of competition with in iduals from other territories. In iduals from the same colony appeared to share information about foraging sites, presumably contributing to the establishment and maintenance of specific, long-term colonial territories.
Publisher: Wiley
Date: 05-12-2016
DOI: 10.1111/ECOG.02817
Publisher: Wiley
Date: 26-12-2017
DOI: 10.1111/ECOG.03371
Publisher: The Royal Society
Date: 07-2020
Abstract: Analyses of morphological disparity have been used to characterize and investigate the evolution of variation in the anatomy, function and ecology of organisms since the 1980s. While a ersity of methods have been employed, it is unclear whether they provide equivalent insights. Here, we review the most commonly used approaches for characterizing and analysing morphological disparity, all of which have associated limitations that, if ignored, can lead to misinterpretation. We propose best practice guidelines for disparity analyses, while noting that there can be no ‘one-size-fits-all’ approach. The available tools should always be used in the context of a specific biological question that will determine data and method selection at every stage of the analysis.
Publisher: Wiley
Date: 18-02-2013
DOI: 10.1111/ELE.12086
Abstract: Ecological stability is touted as a complex and multifaceted concept, including components such as variability, resistance, resilience, persistence and robustness. Even though a complete appreciation of the effects of perturbations on ecosystems requires the simultaneous measurement of these multiple components of stability, most ecological research has focused on one or a few of those components analysed in isolation. Here, we present a new view of ecological stability that recognises explicitly the non-independence of components of stability. This provides an approach for simplifying the concept of stability. We illustrate the concept and approach using results from a field experiment, and show that the effective dimensionality of ecological stability is considerably lower than if the various components of stability were unrelated. However, strong perturbations can modify, and even decouple, relationships among in idual components of stability. Thus, perturbations not only increase the dimensionality of stability but they can also alter the relationships among components of stability in different ways. Studies that focus on single forms of stability in isolation therefore risk underestimating significantly the potential of perturbations to destabilise ecosystems. In contrast, application of the multidimensional stability framework that we propose gives a far richer understanding of how communities respond to perturbations.
Publisher: Cold Spring Harbor Laboratory
Date: 09-12-2022
DOI: 10.1101/2022.12.06.519315
Abstract: The capacity of ectotherms to adjust their thermal tolerance limits through evolution or acclimation seems relatively modest and highly variable, and we lack satisfying explanations for both findings given a limited understanding of what ultimately determines an organism’s thermal tolerance. Here, we test if the amount of heating an ectotherm tolerates throughout a heating event until organismal failure scales with temperature’s non-linear influence on biological rates. To account for the non-linear influence of temperature on biological rates on heating tolerance, we rescaled the duration of heating events of 316 ectothermic taxa acclimated to different temperatures and describe the biological rate-corrected heating duration. This rescaling reveals that the capacity of an organism to resist a heating event is in fact remarkably constant across any acclimation temperature, enabling high-precision estimates of how organismal thermal tolerance limits vary under different thermal regimes. We also find that faster heating consistently reduces biological rate-corrected heating durations, which helps further explain why thermal tolerance limits seem so variable on absolute temperature scales. Existing paradigms are that heating tolerances and thermal tolerance limits reflect incomplete metabolic compensatory responses, are constrained by evolutionary conservatism, or index failure of systems such as membrane function our data provide a different perspective and show that an organism’s thermal tolerance emerges from the interaction between the non-linear thermal dependence of biological rates and heating durations, which is an approximately-fixed property of a species.
Publisher: The Royal Society
Date: 07-06-2014
Abstract: Maximum lifespan in birds and mammals varies strongly with body mass such that large species tend to live longer than smaller species. However, many species live far longer than expected given their body mass. This may reflect interspecific variation in extrinsic mortality, as life-history theory predicts investment in long-term survival is under positive selection when extrinsic mortality is reduced. Here, we investigate how multiple ecological and mode-of-life traits that should reduce extrinsic mortality (including volancy (flight capability), activity period, foraging environment and fossoriality), simultaneously influence lifespan across endotherms. Using novel phylogenetic comparative analyses and to our knowledge, the most species analysed to date ( n = 1368), we show that, over and above the effect of body mass, the most important factor enabling longer lifespan is the ability to fly. Within volant species, lifespan depended upon when (day, night, dusk or dawn), but not where (in the air, in trees or on the ground), species are active. However, the opposite was true for non-volant species, where lifespan correlated positively with both arboreality and fossoriality. Our results highlight that when studying the molecular basis behind cellular processes such as those underlying lifespan, it is important to consider the ecological selection pressures that shaped them over evolutionary time.
Publisher: Wiley
Date: 2006
Publisher: Wiley
Date: 30-06-2021
Abstract: Regional endothermy has evolved several times in marine fishes, and two competing hypotheses are generally proposed to explain the evolutionary drivers behind this trait: thermal niche expansion and elevated cruising speeds. Evidence to support either hypothesis is equivocal, and the ecological advantages conferred by endothermy in fishes remain debated. By compiling published biologging data and collecting precise speed measurements from free‐swimming fishes in the wild, we directly test whether endothermic fishes encounter broader temperature ranges, swim faster or both. Our analyses avoid several complications associated with earlier tests of these hypotheses, as we use precise measurements of the thermal experience and speed of in idual fish. Phylogenetically‐informed analyses of 89 studies reporting temperature ranges encountered by tagged fishes reveal that endotherms do not encounter broader temperature ranges than their ectothermic counterparts. In contrast, speed measurements from 45 in iduals (16 species, of which four were regional endotherms) show that endothermic fishes cruise ~1.6 times faster than ectotherms, after accounting for the influence of body temperature and body mass on speed. Our study shows that regionally endothermic fishes—those with the ability to conserve metabolically derived heat through vascular countercurrent heat exchangers and elevate the temperature of internal tissues—swim at elevated cruising speeds, although not as fast as previously thought. Contrary to previous studies of endothermy's role in thermal niche expansion, our results suggest the significance of endothermy in fishes lies in the advantages it confers to swimming performance rather than facilitating the occupation of broader thermal niches. Given speed's major influence on metabolic rate, our updated speed estimates imply endotherms have lower routine energy requirements than current estimates. Our findings shed light on the evolutionary drivers of regional endothermy in fishes and question the view that the trait confers resilience to climate change through broader thermal tolerance than that of ectotherms. A free Plain Language Summary can be found within the Supporting Information of this article.
Publisher: Wiley
Date: 27-02-2021
DOI: 10.1111/ELE.13704
Abstract: Life history strategies are fundamental to the ecology and evolution of organisms and are important for understanding extinction risk and responses to global change. Using global datasets and a multiple response modelling framework we show that trait‐climate interactions are associated with life history strategies for a erse range of plant species at the global scale. Our modelling framework informs our understanding of trade‐offs and positive correlations between elements of life history after accounting for environmental context and evolutionary and trait‐based constraints. Interactions between plant traits and climatic context were needed to explain variation in age at maturity, distribution of mortality across the lifespan and generation times of species. Mean age at maturity and the distribution of mortality across plants’ lifespan were under evolutionary constraints. These findings provide empirical support for the theoretical expectation that climatic context is key to understanding trait to life history relationships globally.
Publisher: Wiley
Date: 19-07-2016
DOI: 10.1111/ELE.12648
Abstract: Human actions challenge nature in many ways. Ecological responses are ineluctably complex, demanding measures that describe them succinctly. Collectively, these measures encapsulate the overall 'stability' of the system. Many international bodies, including the Intergovernmental Science-Policy Platform on Bio ersity and Ecosystem Services, broadly aspire to maintain or enhance ecological stability. Such bodies frequently use terms pertaining to stability that lack clear definition. Consequently, we cannot measure them and so they disconnect from a large body of theoretical and empirical understanding. We assess the scientific and policy literature and show that this disconnect is one consequence of an inconsistent and one-dimensional approach that ecologists have taken to both disturbances and stability. This has led to confused communication of the nature of stability and the level of our insight into it. Disturbances and stability are multidimensional. Our understanding of them is not. We have a remarkably poor understanding of the impacts on stability of the characteristics that define many, perhaps all, of the most important elements of global change. We provide recommendations for theoreticians, empiricists and policymakers on how to better integrate the multidimensional nature of ecological stability into their research, policies and actions.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Andrew Jackson.