1. Seed dispersal is an essential, yet often overlooked process in plant ecology and evolution, affecting adaptation capacity, population persistence and invasiveness. A species' ability to disperse ...is expected to covary with other life-history traits to form dispersal syndromes. Dispersal might be linked to the rate of life history, fecundity or generation time, depending on the relative selection pressures of bethedging, kin competition or maintaining gene flow. However, the linkage between dispersal and plant life-history strategies remains unknown because it is difficult to observe, quantify and manipulate the influence of dispersal over large spatiotemporal scales. 2. We integrate datasets describing plant vital rates, dispersal and functional traits to incorporate dispersal explicitly into the rich spectra of plant life-history strategies. For 141 plant species, we estimated dispersal ability by predicting maximum dispersal distances using allometric relationships based on growth form, dispersal mode, terminal velocity and seed mass. We derived life-history traits from matrix population models parameterized with field data from the COMPADRE Plant Matrix Database. We analysed the covariation in dispersal ability and life-history traits using multivariate techniques. 3. We found that three main axes of variation described plant dispersal syndromes: the fast-slow life-history continuum, the dispersal strategy axis and the reproductive strategy axis. On the dispersal strategy axis, species' dispersal abilities were positively correlated with aspects of fast life histories. Species with a high net reproductive rate, a long window of reproduction, low likelihood of escaping senescence and low shrinkage tendencies disperse their seeds further. The overall phylogenetic signal in our multidimensional analyses was low (Pagel's λ < 0.24), implying a high degree of taxonomic generality in our findings. 4. Synthesis. Dispersal has been largely neglected in comparative demographic studies, despite its pivotal importance for populations. Our explicit incorporation of dispersal in a comparative life-history framework provides key insights to bridge the gap between dispersal ecology and life-history traits. Species with fast life-history strategies disperse their seeds further than slow-living plants, suggesting that longer dispersal distances may allow these species to take advantage of habitats varying unpredictably in space and time as a bet-hedging strategy.
Life histories are not just fast or slow Stott, Iain; Salguero-Gómez, Roberto; Jones, Owen R. ...
Trends in ecology & evolution (Amsterdam),
07/2024
Journal Article
Recenzirano
Odprti dostop
Life history studies support the fast–slow continuum as the dominant but not unique axis structuring life history variation.Other important axes of life history variation associated with development ...and reproductive tactics exist, and exploration of further axes, clusters, and boundaries of life history variation is needed.Existing life history analyses are venturing far from theory and could benefit from a stronger focus on hypothesis testing rather than exploration.We make recommendations to identify the structuring axes of life history variation through data choices and analytical methods of dimensionality reduction with recourse to a comprehensive model of life history.
Life history strategies, which combine schedules of survival, development, and reproduction, shape how natural selection acts on species’ heritable traits and organismal fitness. Comparative analyses have historically ranked life histories along a fast–slow continuum, describing a negative association between time allocation to reproduction and development versus survival. However, higher-quality, more representative data and analyses have revealed that life history variation cannot be fully accounted for by this single continuum. Moreover, studies often do not test predictions from existing theories and instead operate as exploratory exercises. To move forward, we offer three recommendations for future investigations: standardizing life history traits, overcoming taxonomic siloes, and using theory to move from describing to understanding life history variation across the Tree of Life.
Life history strategies, which combine schedules of survival, development, and reproduction, shape how natural selection acts on species’ heritable traits and organismal fitness. Comparative analyses have historically ranked life histories along a fast–slow continuum, describing a negative association between time allocation to reproduction and development versus survival. However, higher-quality, more representative data and analyses have revealed that life history variation cannot be fully accounted for by this single continuum. Moreover, studies often do not test predictions from existing theories and instead operate as exploratory exercises. To move forward, we offer three recommendations for future investigations: standardizing life history traits, overcoming taxonomic siloes, and using theory to move from describing to understanding life history variation across the Tree of Life.
Understanding the factors that regulate temporal changes in population size is a core aspiration in ecology given the importance of population stability on the maintenance of species interactions, ...effects on local communities, the stability of ecosystems, and for biodiversity conservation. Understanding temporal trends in population size can support management practices as this may indicate demographic resilience for exploited species. Theoretical studies have long suggested that life‐history traits regulate population stability, but empirical support remains limited, especially for species‐rich environments. Additionally, harvesting has been suggested as an important factor increasing the fluctuation in the number of individuals in populations.
In this study, we analysed population stability of 70 Amazonian floodplain fish species in relation to life‐history traits and the degree of fishing pressure. Our data covered a long time scale and broad geographical range of the Amazon floodplain. For that, we compiled datasets of two monitoring programmes, one comprising data from a single lake for 15 years and a second dataset with information from three floodplain lakes sampled over 5 years. The resulting geographical range spanned one of the most fished areas in the upper Amazon River, between the municipalities of Coari and Manaus, in the Brazilian Amazon. Temporal stability was measured as the coefficient of variation in species abundance. Population life‐history traits and the degree of fishing pressure were estimated at the species level.
Population temporal stability had significant relationships with three life‐history traits: maximum body size, fecundity, somatic investment before sexual maturation (SIBSM), and the interaction of fecundity and SIBSM. Species with small body size, high fecundity, and low SIBSM displayed low stability; the opposite happened to species that invest highly in somatic tissue before the first reproduction and have large body size. Fishing pressure had no significant contribution to explaining population stability. However, the sampling technique employed and the set of species considered in the study do not represent main targets of fisheries.
Here we stress the importance of life‐history traits in controlling an essential part of the population size variation in a complex and species‐rich fish assemblage in the Amazon floodplains. Our results highlight the importance of the trade‐off between growth and reproduction in controlling population stability and complement explanations on how life‐history functional traits underlie differences in population dynamics over time. Our results contribute to theoretical development and can be used to support fisheries and biological conservation management strategies. Specifically, our results point to the possibility of inferring demographic resilience based on life‐history information in the absence of high‐quality population data.
The pace-of-life syndrome (i.e., POLS) hypothesis posits that behavioral and physiological traits mediate the trade-off between current and future reproduction. This hypothesis predicts that life ...history, behavioral, and physiological traits will covary under clearly defined conditions. Empirical tests are equivocal and suggest that the conditions necessary for the POLS to emerge are not always met. We nuance and expand the POLS hypothesis to consider alternative relationships among behavior, physiology, and life history. These relationships will vary with the nature of predation risk, the challenges posed by resource acquisition, and the energy management strategies of organisms. We also discuss how the plastic response of behavior, physiology, and life history to changes in ecological conditions and variation in resource acquisition among individuals determine our ability to detect a fast-slow pace of life in the first place or associations among these traits. Future empirical studies will provide most insights on the coevolution among behavior, physiology, and life history by investigating these traits both at the genetic and phenotypic levels in varying types of predation regimes and levels of resource abundance.
Temporal autocorrelation in demographic processes is an important aspect of population dynamics, but a comprehensive examination of its effects on different life‐history strategies is lacking. We use ...matrix population models from 454 plant and animal populations to simulate stochastic population growth rates (log λs) under different temporal autocorrelations in demographic rates, using simulated and observed covariation among rates. We then test for differences in sensitivities, or changes of log λs to changes in autocorrelation among two major axes of life‐history strategies, obtained from phylogenetically informed principal component analysis: the fast‐slow and reproductive‐strategy continua. Fast life histories exhibit highest sensitivities to simulated autocorrelation in demographic rates across reproductive strategies. Slow life histories are less sensitive to temporal autocorrelation, but their sensitivities increase among highly iteroparous species. We provide cross‐taxonomic evidence that changes in the autocorrelation of environmental variation may affect a wide range of species, depending on complex interactions of life‐history strategies.
In ectotherms, growth rate, body size and maturation rate covary with temperature, with the direction and magnitude of variation predicted by the Temperature‐Size Rule (TSR). Nutritional quality or ...availability of food, however, may vary over latitudinal gradients, resulting in ambiguous effects on body size and maturation rate. The Temperature‐Constraint Hypothesis (TCH) predicts that marine herbivorous ectotherms are nutritionally compromised at latitudes exceeding 30°. This provides an opportunity to resolve the contrasting demographic responses of ectotherms to variation in temperature and nutritional status over latitudinal gradients. This study uses analysis of demographic rates to evaluate the predictions of the TSR in a marine herbivorous ectotherm sampled over a significant latitudinal gradient. The direction and magnitude of demographic variation was established in the marine herbivorous fish, Odax pullus (the butterfish), and compared with that of a phylogenetically related but trophically distinct species, the carnivorous Notolabrus fucicola (the banded wrasse). Both species were sampled at three locations across the length of New Zealand covering latitudes between 35°S and 49°S. Growth rate, mean size‐at‐age, age‐ and size‐at‐maturity, life span and abundance were estimated for each species at each location. Demographic traits of both taxa varied with latitude. Both species showed slower initial growth rates, and matured later at a larger body size at higher latitudes than populations sampled at lower latitudes. In addition, abundances increased significantly at higher latitudes in both species. These results were consistent with the TSR but not with the TCH, confirming that nutritional ecology (herbivore vs. carnivory) did not determine demographic patterns over a biologically significant latitudinal gradient. Results from this study suggest that the absence of herbivorous reef fishes from the higher latitudes of the Northern Hemisphere may not reflect a general physiological mechanism as suggested by the TCH and highlights the need to clarify the evolutionary histories of the marine biota of each hemisphere.
Mammalian life history strategies can be characterised by a few axes of variation, conforming a space where species are positioned based on the life history strategies favoured in the environment ...they exploit. Yet, we still lack global descriptions of the diversity of realised mammalian life history and how this diversity is shaped by the environment. We used six life history traits to build a life history space covering worldwide mammalian adaptation, and we explored how environmental realms (land, air, water) influence mammalian life history strategies. We demonstrate that realms are tightly linked to distinct life history strategies. Aquatic and aerial species predominantly adhere to slower life history strategies, while terrestrial species exhibit faster life histories. Highly encephalised terrestrial species are a notable exception to these patterns. Furthermore, we show that different mode of life may play a significant role in expanding the set of strategies exploitable in the terrestrial realm. Additionally, species transitioning between terrestrial and aquatic realms, such as seals, exhibit intermediate life history strategies. Our results provide compelling evidence of the link between environmental realms and the life history diversity of mammals, highlighting the importance of differences in mode of life to expand life history diversity.
Employing six life history traits across 3438 mammalian species, we explored patterns in life history strategies. We demonstrate that worldwide mammals aggregate around two opposite strategies: fast and slow pace of life, with few intermediates. Environmental realms (land, air, water, semi‐aquatic) emerge as robust predictors of this dichotomy. Notably, differences in species' ecological adaptations, like mode of life, substantially expand the diversity of strategies within each realm.
In this volume, Albert Hirschman reconstructs the intellectual climate of the seventeenth and eighteenth centuries to illuminate the intricate ideological transformation that occurred, wherein the ...pursuit of material interests--so long condemned as the deadly sin of avarice--was assigned the role of containing the unruly and destructive passions of man. Hirschman here offers a new interpretation for the rise of capitalism, one that emphasizes the continuities between old and new, in contrast to the assumption of a sharp break that is a common feature of both Marxian and Weberian thinking. Among the insights presented here is the ironical finding that capitalism was originally supposed to accomplish exactly what was soon denounced as its worst feature: the repression of the passions in favor of the "harmless," if one-dimensional, interests of commercial life. To portray this lengthy ideological change as an endogenous process, Hirschman draws on the writings of a large number of thinkers, including Montesquieu, Sir James Steuart, and Adam Smith.
Featuring a new afterword by Jeremy Adelman and a foreword by Amartya Sen, this Princeton Classics edition ofThe Passions and the Interestssheds light on the intricate ideological transformation from which capitalism emerged triumphant, and reaffirms Hirschman's stature as one of our most influential and provocative thinkers.
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