Balancing growth amidst salt stress - lifestyle perspectives from the extremophyte model Schrenkiella parvula.

Schrenkiella parvula, a leading extremophyte model in Brassicaceae, can grow and complete its lifecycle under multiple environmental stresses, including high salinity. Yet, the key physiological and structural traits underlying its stress-adapted lifestyle are unknown along with trade-offs when surviving salt stress at the expense of growth and reproduction. We aimed to identify the influential adaptive trait responses that lead to stress-resilient and uncompromised growth across developmental stages when treated with salt at levels known to inhibit growth in Arabidopsis and most crops. Its resilient growth was promoted by traits that synergistically allowed primary root growth in seedlings, the expansion of xylem vessels across the root-shoot continuum, and a high capacity to maintain tissue water levels by developing thicker succulent leaves while enabling photosynthesis during salt stress. A successful transition from vegetative to reproductive phase was initiated by salt-induced early flowering, resulting in viable seeds. Self-fertilization in salt-induced early flowering was dependent upon filament elongation in flowers otherwise aborted in the absence of salt during comparable plant ages. The maintenance of leaf water status promoting growth, and early flowering to ensure reproductive success in a changing environment, were among the most influential traits that contributed to the extremophytic lifestyle of S. parvula.

Living fast, dying young: Anthropogenic habitat modification influences the fitness and life history traits of a cooperative breeder.

Anthropogenic habitat modification can indirectly effect reproduction and survival in social species by changing the group structure and social interactions. We assessed the impact of habitat modification on the fitness and life history traits of a cooperative breeder, the Arabian babbler (Argya squamiceps). We collected spatial, reproductive and social data on 572 individuals belonging to 21 social groups over 6 years and combined it with remote sensing to characterize group territories in an arid landscape. In modified resource-rich habitats, groups bred more and had greater productivity, but individuals lived shorter lives than in natural habitats. Habitat modification favoured a faster pace-of-life with lower dispersal and dominance acquisition ages, which might be driven by higher mortality providing opportunities for the dominant breeding positions. Thus, habitat modification might indirectly impact fitness through changes in social structures. This study shows that trade-offs in novel anthropogenic opportunities might offset survival costs by increased productivity.

Flower-bee versus pollen-bee metanetworks in fragmented landscapes.

Understanding the organization of mutualistic networks at multiple spatial scales is key to ensure biological conservation and functionality in human-modified ecosystems. Yet, how changing habitat and landscape features affect pollen-bee interaction networks is still poorly understood. Here, we analysed how bee-flower visitation and bee-pollen-transport interactions respond to habitat fragmentation at the local network and regional metanetwork scales, combining data from 29 fragments of calcareous grasslands, an endangered biodiversity hotspot in central Europe. We found that only 37% of the total unique pairwise species interactions occurred in both pollen-transport and flower visitation networks, whereas 28% and 35% were exclusive to pollen-transport and flower visitation networks, respectively. At local level, network specialization was higher in pollen-transport networks, and was negatively related to the diversity of land cover types in both network types. At metanetwork level, pollen transport data revealed that the proportion of single-fragment interactions increased with landscape diversity. Our results show that the specialization of calcareous grasslands' plant-pollinator networks decreases with landscape diversity, but network specialization is underestimated when only based on flower visitation information. Pollen transport data, more than flower visitation, and multi-scale analyses of metanetworks are fundamental for understanding plant-pollinator interactions in human-dominated landscapes.

Exact confidence intervals for population growth rate, longevity and generation time.

By quantifying key life history parameters in populations, such as growth rate, longevity, and generation time, researchers and administrators can obtain valuable insights into its dynamics. Although point estimates of demographic parameters have been available since the inception of demography as a scientific discipline, the construction of confidence intervals has typically relied on approximations through series expansions or computationally intensive techniques. This study introduces the first mathematical expression for calculating confidence intervals for the aforementioned life history traits when individuals are unidentifiable and data are presented as a life table. The key finding is the accurate estimation of the confidence interval for r, the instantaneous growth rate, which is tested using Monte Carlo simulations with four arbitrary discrete distributions. In comparison to the bootstrap method, the proposed interval construction method proves more efficient, particularly for experiments with a total offspring size below 400. We discuss handling cases where data are organized in extended life tables or as a matrix of vital rates. We have developed and provided accompanying code to facilitate these computations.

Telomeres and telomerase: active but complex players in life-history decisions.

Studies on human telomeres have established that telomeres exert a significant influence on lifespan and health of organisms. However, recent research has indicated that the original idea that telomeres affect lifespan in a universal and central manner across all eukaryotic species is an oversimplification. Indeed, findings from a variety of animal species revealed that the role of telomere biology in aging is more subtle and intricate than previously recognized. Here, we show how telomere biology varies depending on the taxon. We also show how telomere biology corresponds to basic life history traits and affects the life table of a species and investments in growth, body size, reproduction, and lifespan; telomeres are hypothesized to shape evolutionary perspectives for species in an active but complex manner. Our evaluation is based on telomere biology data from many examples from throughout the animal kingdom that vary according to the degree of organismal complexity and life history strategies.

Temperature-dependent dispersal and ectotherm species' distributions in a warming world.

Dispersal is a crucial component of species' responses to climate warming. Warming-induced changes in species' distributions are the outcome of how temperature affects dispersal at the individual level. Yet, there is little or no theory that considers the temperature dependence of dispersal when investigating the impacts of warming on species' distributions. Here I take a first step towards filling this key gap in our knowledge. I focus on ectotherms, species whose body temperature depends on the environmental temperature, not least because they constitute the majority of biodiversity on the planet. I develop a mathematical model of spatial population dynamics that explicitly incorporates mechanistic descriptions of ectotherm life history trait responses to temperature. A novel feature of this framework is the explicit temperature dependence of all phases of dispersal: emigration, transfer and settlement. I report three key findings. First, dispersal, regardless of whether it is random or temperature-dependent, allows both tropical and temperate ectotherms to track warming-induced changes in their thermal environments and to expand their distributions beyond the lower and upper thermal limits of their respective climate envelopes. In the absence of dispersal mortality, warming does not alter these new distributional limits. Second, an analysis based solely on trait response data predicts that tropical ectotherms should be able to expand their distributions polewards to a greater degree than temperate ectotherms. Analysis of the dynamical model confirms this prediction. Tropical ectotherms have an advantage when moving to cooler climates because they experience lower within-patch and dispersal mortality, and their higher thermal optima and maximal birth rates allow them to take advantage of the warmer parts of the year. Previous theory has shown that tropical ectotherms are more successful in invading and adapting the temperate climates than vice versa. This study provides the key missing piece, by showing how temperature-dependent dispersal could facilitate both invasion and adaptation. Third, dispersal mortality does not affect the poleward expansion of ectotherm distributions. But, it prevents both tropical and temperate ectotherms from maintaining sink populations in localities that are too warm to be viable in the absence of dispersal. Dispersal mortality also affects species' abundance patterns, causing a larger decline in abundance throughout the range when species disperse randomly rather than in response to thermal habitat suitability. In this way, dispersal mortality can facilitate the evolution of dispersal modes that maximize fitness in warmer thermal environments.

A test of trade-offs in dispersal and reproduction within and between a sister species pair of specialist insect herbivores.

Understanding the drivers of trade-offs among traits is vital for comprehending the evolution and maintenance of trait variation. Theoretical frameworks propose that evolutionary mechanisms governing trade-offs frequently exhibit a scale-dependent nature. However, empirical tests of whether trade-offs exhibited across various biological scales (i.e. individuals, populations, species, genera, etc.) remains scarce. In this study, we explore trade-off between dispersal and reproductive effort among sympatric sister species of wasps in the genus Belonocnema (Hymenoptera: Cynipini: Cynipidae) that form galls on live oaks: B. fossoria, which specializes on Quercus geminata, and B. treatae, which specializes on Q. virginiana. Specifically, our results suggest that B. fossoria has evolved reduced flight capability and smaller wings, but a larger abdomen and greater total reproductive effort than B. treatae, which has larger wings and is a stronger flier, but has a smaller abdomen and reduced total reproductive effort. These traits and the relationships among them remain unchanged when B. fossoria and B. treatae are transplanted and reared onto the alternative host plant, suggesting that trait divergence is genetically based as opposed to being a plastic response to the different rearing environments. However, when looking within species, we found no evidence of intraspecific trade-offs between wing length and reproductive traits within either B. fossoria or B. treatae. Overall, our results indicate that observed trade-offs in life history traits between the two gall former species are likely a result of independent adaptations in response to different environments as opposed to the amplified expression of within species intrinsic tradeoffs.

Effects of warming at embryonic and larval stages on tadpole fitness in high-altitude Rana kukunoris.

Global warming may affect the early developmental stages of high-altitude amphibians, thereby influencing their later fitness. Yet, this has been largely unexplored. To investigate whether and how the temperatures experienced by embryonic and larval stages affect their fitness at later developmental stages, we designed two experiments in which the embryos and larvae were treated with three temperatures (24, 18 and 12 °C), respectively. Then, the life history traits of the tadpoles during the metamorphotic climax in all treatments were evaluated, including growth rate, survival rate, morphology, thermal physiology, swimming performance, standard metabolic rate (SMR), oxidative and antioxidative system, and metabolic enzyme activities. The results revealed that elevated temperature accelerated metamorphosis but decreased body size at metamorphosis. Additionally, warming during the embryonic and larval stages decreased the thermal tolerance range and induced increased oxidative stress. Furthermore, high embryonic temperature significantly decreased the hatching success, but had no significant effect on swimming performance and SMR. Warming during larval periods was harmful to the survival and swimming performance of tadpoles. The effect size analysis revealed that the negative impacts of embryonic temperature on certain physiological traits, such as growth and development, survival and swimming performance, were more pronounced than those of larval temperature. Our results highlight the necessity for particular attention to be paid to the early stages of amphibians, notably the embryonic stages when evaluating the impact of global warming on their survival.

A multi-population approach supports common patterns in marine growth and maturation decision in Atlantic salmon (Salmo salar L.) from southern Europe.

This study provides a regional picture of long-term changes in Atlantic salmon growth at the southern edge of their distribution, using a multi-population approach spanning 49 years and five populations. We provide empirical evidence of salmon life history being influenced by a combination of common signals in the marine environment and population-specific signals. We identified an abrupt decline in growth from 1976 and a more recent decline after 2005. As these declines have also been recorded in northern European populations, our study significantly expands a pattern of declining marine growth to include southern European populations, thereby revealing a large-scale synchrony in marine growth patterns for almost five decades. Growth increments during their sea sojourn were characterized by distinct temporal dynamics. At a coarse temporal resolution, growth during the first winter at sea seemed to gradually improve over the study period. However, the analysis of finer seasonal growth patterns revealed ecological bottlenecks of salmon life histories at sea in time and space. Our study reinforces existing evidence of an impact of early marine growth on maturation decision, with small-sized individuals at the end of the first summer at sea being more likely to delay maturation. However, each population was characterized by a specific probabilistic maturation reaction norm, and a local component of growth at sea in which some populations have better growth in some years might further amplify differences in maturation rate. Differences between populations were smaller than those between sexes, suggesting that the sex-specific growth threshold for maturation is a well-conserved evolutionary phenomenon in salmon. Finally, our results illustrate that although most of the gain in length occurs during the first summer at sea, the temporal variability in body length at return is buffered against the decrease in post-smolt growth conditions. The intricate combination of growth over successive seasons, and its interplay with the maturation decision, could be regulating body length by maintaining diversity in early growth trajectories, life histories, and the composition of salmon populations.

Reduction in size-at-maturity in unprecedentedly strong cohorts of redfish (Sebastes mentella and S. fasciatus) in the Gulf of St. Lawrence and Laurentian Channel.

Life-history traits, such as size-at-maturity, are key parameters to model population dynamics used to inform fisheries management. Fishery-induced evolution, density-dependent effects, and global warming have been shown to affect size- and age-at-maturity, and resulting spawning stock biomass (SSB) in a wide range of commercial fish stocks. Marked changes in redfish biomass and environmental conditions in the Gulf of St. Lawrence and Laurentian Channel over the past decade called for a review and update of size-at-maturity for commercially important deepwater redfish Sebastes mentella and Acadian redfish Sebastes fasciatus stocks. Following a 25-year moratorium, local redfish biomass has recently reached unprecedented levels, co-occurring with an overall warming of bottom water temperatures. Our objectives were (1) to perform a histological assessment of redfish reproduction stages, including the validation and fine-tuning of a robust visual chart to facilitate monitoring of size-at-maturity and SSB in a transforming environment, and (2) to evaluate changes in size-at-maturity in unprecedentedly strong cohorts of redfish, and consequences for stock status assessment and fisheries management. Each specimen was genetically identified to species, and gonad reproduction stages were determined by histology and macroscopic appearances. The present study enabled a robust visual chart for continued and cost-effective monitoring of redfish reproduction stages to be refined and validated, and has shown a large decrease in redfish length when 50% of the individuals are considered mature that led to an increase in estimates of SSB during the 2011-2021 period for S. mentella and S. fasciatus. These changes modified the perception of stock status, thus having significant implications for fisheries management. Given that fishery-induced evolution and community structure changes along with global warming are affecting numerous stocks worldwide, the present study outlines a major and global challenge for scientists and resources managers. As shown by our results, the monitoring and frequent updates of life-history traits in transforming environments are needed to provide reliable science advice for sustainable fisheries.

The effect of placentation type, litter size, lactation and gestation length on cancer risk in mammals.

Reproduction is a central activity for all living organisms but is also associated with a diversity of costs that are detrimental for survival. Until recently, the cost of cancer as a selective force has been poorly considered. Considering 191 mammal species, we found cancer mortality was more likely to be detected in species having large, rather than low, litter sizes and long lactation lengths regardless of the placentation types. However, increasing litter size and gestation length are not per se associated with an enhanced cancer mortality risk. Contrary to basic theoretical expectations, the species with the highest cancer mortality were not those with the most invasive (i.e. haemochorial) placentation, but those with a moderately invasive (i.e. endotheliochorial) one. Overall, these results suggest that (i) high reproductive efforts favour oncogenic processes' dynamics, presumably because of trade-offs between allocation in reproduction effort and anti-cancer defences, (ii) cancer defence mechanisms in animals are most often adjusted to align reproductive lifespan, and (iii) malignant cells co-opt existing molecular and physiological pathways for placentation, but species with the most invasive placentation have also selected for potent barriers against lethal cancers. This work suggests that the logic of Peto's paradox seems to be applicable to other traits that promote tumorigenesis.

Senescence and the stress axis: a constraint or a trade-off of reproduction in mammals with fast and slow life histories.

A critical time in the life of a male occurs at reproduction, when his behaviour, physiology and resources must be brought to bear for the central purpose of his life-propagating his genes. We ask whether reproduction results in dysfunction of the stress axis, is linked to life history, and causes senescence. We assessed if deterioration in the axis underlies variation in reproductive lifespan in males of five species of North American ground squirrels whose life history varies from near semelparity to iteroparity. The most stressful and energy-demanding time occurs in spring during the intense 2-3 week breeding competition just after arousal from hibernation. We compared their stress axis functioning before and after the mating period using a hormonal challenge protocol. We found no evidence of stress axis dysfunction after reproduction in any species nor was there a relationship between reproductive lifespan and stress axis functional deterioration. Moreover, there was no consistent relationship between free cortisol levels and downstream measures (energy mobilization, haematology, immunity and body indices of condition). Thus, stress axis function was not traded off to promote reproduction irrespective of life history and lifespan, and we conclude that it is a prerequisite for life. Hence, it functions as a constraint and does not undergo senescence.

Mapping the nutritional landscape in the yellow mealworm: testing the nutrient-mediated life-history trade-offs.

Animals must acquire an ideal amount and balance of macronutrients to optimize their performance, health and fitness. The nutritional landscape provides an integrative framework for analysing how animal phenotypes are associated with multiple nutritional components. Here, we applied this powerful approach to examine how the intake of protein and carbohydrate affects nutrient acquisition and performance in the yellow mealworm (Tenebrio molitor) reared on one of 42 synthetic foods varying in protein and carbohydrate content. Tenebrio molitor larvae increased their food consumption rate in response to nutrient dilution, but this increase was not sufficient to fully compensate for the dilution. Diluting the food nutrient content with cellulose reduced the efficiency of post-ingestive nutrient utilization, further restricting macronutrient acquisition. Tenebrio molitor larvae utilized macronutrients most efficiently at a protein to carbohydrate (P:C) ratio of 1.77:1, but became less efficient at imbalanced P:C ratios. Survivorship was high at high protein intake and fell with decreasing protein intake. Pupal mass and growth rate exhibited a bell-shaped landscape, with the nutritional optima being located around protein-biased P:C ratios of 1.99:1 to 2.03:1 and 1.66:1 to 2.86:1, respectively. The nutritional optimum for development time was also identified at high P:C ratios (1.66:1  to 5.86:1). Unlike these performance traits, lipid content was maximized at carbohydrate-biased P:C ratios of 1:3.88 to 1:3.06. When given a food choice, T. molitor larvae self-composed a slightly carbohydrate-biased P:C ratio of 1:1.24, which lies between the P:C ratios that maximize performance and lipid content. Our findings indicate the occurrence of a nutrient-mediated trade-off between performance and energy storage in this insect.

Life span, growth, senescence and island syndrome: Accounting for imperfect detection and continuous growth.

Small vertebrates on islands are expected to attain a larger body size, and a greater survival than their mainland counterparts. Comparative studies have questioned whether lizards exhibit this set of adaptations, referred to as the 'island syndrome'. We collected data on 730 individuals the endemic Lilford's lizard Podarcis lilfordi throughout a 10-year period on a small island of the Balearic archipelago (Spain). We coupled a growth function with a capture-mark-recapture model to simultaneously estimate size- and sex-dependent growth rate and survival. To put our results into a wider context, we conducted a systematic review of growth, life span and age at maturity in different Podarcis species comparing insular and mainland populations. We found a low average growth coefficient (0.56 and 0.41 year-1 for males and females to reach an asymptotic size of 72.3 and 65.6 mm respectively), a high annual survival probability of 0.81 and 0.79 in males and females, and a large variability between individuals in growth parameters. Survival probability decreased with body size in both sexes, indicating a senescence pattern typical of long-lived species or in populations with a low extrinsic mortality. Assuming a constant survival after sexual maturity, at about 2 years old, the average life span was 6.18 years in males and 8.99 in females. The oldest animal was a male last captured at an estimated age of ≥13 years and still alive at the end of the study. Our results agree with the predictions of the 'island syndrome' for survival, life span and growth parameters. A comparative analysis of these values across 29 populations of 16 different species of Podarcis indicated that insular lizards grow slower and live longer than their mainland counterparts. However, our data differed from other island populations of the same species, suggesting that island-specific characteristics play an additional role to isolation. Within this study we developed an analytical approach to study the body size-dependent survival of small reptiles. We discuss its applicability to contrast hypotheses on senescence in different sexes of this species, and provide the code used to integrate the growth and capture-mark-recapture models.

Fewer chromosomes, more co-occurring species within plant lineages: A likely effect of local survival and colonization.

PREMISE: Plant lineages differ markedly in species richness globally, regionally, and locally. Differences in whole-genome characteristics (WGCs) such as monoploid chromosome number, genome size, and ploidy level may explain differences in global species richness through speciation or global extinction. However, it is unknown whether WGCs drive species richness within lineages also in a recent, postglacial regional flora or in local plant communities through local extinction or colonization and regional species turnover. METHODS: We tested for relationships between WGCs and richness of angiosperm families across the Netherlands/Germany/Czechia as a region, and within 193,449 local vegetation plots. RESULTS: Families that are species-rich across the region have lower ploidy levels and small monoploid chromosomes numbers or both (interaction terms), but the relationships disappear after accounting for continental and local richness of families. Families that are species-rich within occupied localities have small numbers of polyploidy and monoploid chromosome numbers or both, independent of their own regional richness and the local richness of all other locally co-occurring species in the plots. Relationships between WGCs and family species-richness persisted after accounting for niche characteristics and life histories. CONCLUSIONS: Families that have few chromosomes, either monoploid or holoploid, succeed in maintaining many species in local communities and across a continent and, as indirect consequence of both, across a region. We suggest evolutionary mechanisms to explain how small chromosome numbers and ploidy levels might decrease rates of local extinction and increase rates of colonization. The genome of a macroevolutionary lineage may ultimately control whether its species can ecologically coexist.

Dispersal and establishment traits provide a colonization advantage for a polyploid apomictic plant.

PREMISE: Apomictic plants (reproducing asexually through seed) often have larger ranges and occur at higher latitudes than closely related sexuals, a pattern known as geographical parthenogenesis (GP). Explanations for GP include differences in colonizing ability due to reproductive assurance and direct/indirect effects of polyploidy (most apomicts are polyploid) on ecological tolerances. While life history traits associated with dispersal and establishment also contribute to the potential for range expansion, few studies compare these traits in related apomicts and sexuals. METHODS: We investigated differences in early life history traits between diploid-sexual and polyploid-apomictic Townsendia hookeri (Asteraceae), which displays a classic pattern of GP. Using lab and greenhouse experiments, we measured seed dispersal traits, germination success, and seedling size and survival in sexual and apomictic populations from across the range of the species. RESULTS: While theory predicts that trade-offs between dispersal and establishment traits should be common, this was largely not the case in T. hookeri. Apomictic seeds had both lower terminal velocity (staying aloft longer when dropped) and higher germination success than sexual seeds. While there were no differences in seedling size between reproductive types, apomicts did, however, have slightly lower seedling survival than sexuals. CONCLUSIONS: These differences in early life history traits, combined with reproductive assurance conferred by apomixis, suggest that apomicts achieve a greater range through advantages in their ability to both spread and establish.

Species-level correlates of land-use responses and climate-change sensitivity in terrestrial vertebrates.

Land-use and climate change are major pressures on terrestrial biodiversity. Species' extinction risk and responses to human pressures relate to ecological traits and other characteristics in some clades. However, large-scale comparative assessments of the associations between traits and responses to multiple human pressures across multiple clades are needed. We investigated whether a set of ecological characteristics that are commonly measured across terrestrial vertebrates (ecological traits and geographic range area) are associated with species' responses to different land-use types and species' likely sensitivity to climate change. We aimed to test whether generalizable patterns in response to these pressures arise across both pressures and across vertebrate clades, which could inform assessments of the global signature of human pressures on vertebrate biodiversity and guide conservation efforts. At the species level, we investigated associations between land-use responses and ecological characteristics with a space-for-time substitution approach, making use of the PREDICTS database. We investigated associations between ecological characteristics and expected climate-change sensitivity, estimated from properties of species realized climatic niches. Among the characteristics we considered, 3 were consistently associated with strong land-use responses and high climate-change sensitivity across terrestrial vertebrate classes: narrow geographic range, narrow habitat breadth, and specialization on natural habitats (which described whether a species occurs in artificial habitats or not). The associations of other traits with species' land-use responses and climate-change sensitivity often depended on species' class and land-use type, highlighting an important degree of context dependency. In all classes, invertebrate eaters and fruit and nectar eaters tended to be negatively affected in disturbed land-use types, whereas invertebrate-eating and plant- and seed-eating birds were estimated to be more sensitive to climate change, raising concerns about the continuation of ecological processes sustained by these species under global changes. Our results highlight a consistently higher sensitivity of narrowly distributed species and habitat specialists to land-use and climate change, which provides support for capturing such characteristics in large-scale vulnerability assessments.

Correlaciones a nivel de especie de las respuestas al uso de suelo y la susceptibilidad al cambio climático en los vertebrados terrestres Resumen El uso de suelo y el cambio climático tienen una presión importante sobre la biodiversidad terrestre. En algunos clados, el riesgo de extinción de las especies y las respuestas a las presiones humanas se relacionan con los rasgos ecológicos y otras características. Sin embargo, varios clados necesitan evaluaciones comparativas a gran escala de las asociaciones entre los rasgos y las respuestas a las presiones humanas. Investigamos si un conjunto de rasgos ecológicos medidos comúnmente en los vertebrados terrestres (rasgos ecológicos y extensión del área geográfica) está asociado con la respuesta de las especies a los diferentes tipos de uso de suelo y la posible susceptibilidad de la especie al cambio climático. Buscamos comprobar si los patrones generalizables de las respuestas a estas presiones surgen en ambas presiones y en todos los clados de vertebrados, lo que podría guiar las evaluaciones de la huella mundial de presiones humanas sobre la diversidad de vertebrados y los esfuerzos de conservación. Investigamos las asociaciones entre la respuesta al uso de suelo y los rasgos ecológicos a nivel de especie con una estrategia de reemplazo de espacio por tiempo y con información de la base de datos PREDICTS. También investigamos las asociaciones entre los rasgos ecológicos y la susceptibilidad al cambio climático esperada, la cual estimamos a partir de las propiedades de los nichos climáticos de las especies. Entre las características que consideramos, tres estuvieron asociadas de manera regular con respuestas fuertes al uso de suelo y alta susceptibilidad al cambio climático en las diferentes clases de vertebrados: la extensión geográfica limitada, la amplitud reducida de hábitat y la especialización en los hábitats naturales (la cual describe si una especie está presente en un hábitat artificial o no). Las asociaciones de otros rasgos con la respuesta de la especie al uso de suelo y su susceptibilidad al cambio climático con frecuencia dependieron de la clase de la especie y el tipo de uso de suelo, lo que resalta un grado importante de dependencia del contexto. En todas las clases, los frugívoros, nectarívoros y los que comen invertebrados eran propensos a sufrir efectos negativos en los usos de suelo de tipo perturbado, mientras que se estimó que las aves herbívoras, las que se alimentan de semillas y las que se alimentan de invertebrados eran más susceptibles al cambio climático, lo que incrementa la preocupación por la continuación de los procesos ecológicos que viven estas especies bajo los cambios globales. Nuestros resultados resaltan una susceptibilidad al uso de suelo y al cambio climático cada vez mayor en las especies con distribución limitada y las especialistas de hábitat, lo que proporciona un respaldo para la captura de dichas características en las evaluaciones a gran escala de la vulnerabilidad.

Small Butt Harmful: Individual- and Population-Level Impacts of Cigarette Filter Particles on the Deposit-Feeding Polychaete Capitella teleta.

In the marine environment, discarded cigarette filters (CFs) deteriorate and leach filter-associated chemicals. The study aim was to assess the effects of smoked CFs (SCFs) and non-smoked CFs (NCFs) particles on individual life-history traits in the deposit-feeding polychaete Capitella teleta and extrapolate these to possible population-level effects. C. teleta was exposed to sediment-spiked particles of NCFs and SCFs at an environmentally realistic concentration (0.1 mg particles g-1 dw sed) and a 100-fold higher (10 mg particles g-1 dw sed) concentration. Experimental setup incorporated 11 individual endpoints and lasted approximately 6 months. There were significant effects on all endpoints, except from adult body volume and egestion rate, in worms exposed to 10 mg SCF particles g-1 dw sed. Although not statistically significant, there was ≥50% impact on time between reproductive events and number of eggs per female at 0.1 mg SCF particles g-1 dw sed. None of the endpoints was significantly affected by NCFs. Results suggest that SCFs are likely to affect individual life-history traits of C. teleta, whereas the population model suggests that these effects might not transform into population-level effects. The results further indicate that chemicals associated with CFs are the main driver causing the effects rather than the CF particles.

Fitness cost of Rhagoletis cerasi (Diptera: Tephritidae) adults emerged from pupae with different dormancy regimes: the case of prolonged chilling.

The European cherry fruit fly, Rhagoletis cerasi (Diptera: Tephritidae), is a univoltine species that overwinters at pupal stage. Under optimum overwintering conditions pupae will develop into adults the next spring. Shorter or longer than optimum chilling periods induce prolonged pupae dormancy. Pupae that enter prolonged dormancy due to a short chilling period exhibit high emergence rates after a second cycle of cold/warm periods. Adults found to be larger and less fecund compared to their counterparts from pupae with annual diapause. On the other hand, extreme long chilling periods at pupal stage results in high mortality rates. However, for one Greek population, a substantial number of adults emerged following prolonged chilling of pupae (ca. 18 consecutive months). In this study, we used three R. cerasi populations in order to address possible geographical variation in fitness cost of adults from pupae with prolonged dormancy. In addition, the fitness traits of these adults emerging after prolonged pupae chilling were compared with that of their counterparts from pupae with annual diapause or prolonged dormancy. Our results reveal no population-specific variation in fitness cost of adults from pupae with prolonged dormancy. Within a population, lifetime fecundity did not differ between adults emerged from pupae with prolonged dormancy and those emerged after prolonged pupae chilling. Adults emerged from pupae exposed to prolonged chilling suffer an additional reduction in adult longevity compared to adults from pupae with prolonged dormancy. Hence, fitness of R. cerasi adults is regulated by diapause regimes of pupae.

Mismatches between demographic niches and geographic distributions are strongest in poorly dispersed and highly persistent plant species.

The ecological niche of a species describes the variation in population growth rates along environmental gradients that drives geographic range dynamics. Niches are thus central for understanding and forecasting species' geographic distributions. However, theory predicts that migration limitation, source-sink dynamics, and time-lagged local extinction can cause mismatches between niches and geographic distributions. It is still unclear how relevant these niche-distribution mismatches are for biodiversity dynamics and how they depend on species life-history traits. This is mainly due to a lack of the comprehensive, range-wide demographic data needed to directly infer ecological niches for multiple species. Here we quantify niches from extensive demographic measurements along environmental gradients across the geographic ranges of 26 plant species (Proteaceae; South Africa). We then test whether life history explains variation in species' niches and niche-distribution mismatches. Niches are generally wider for species with high seed dispersal or persistence abilities. Life-history traits also explain the considerable interspecific variation in niche-distribution mismatches: poorer dispersers are absent from larger parts of their potential geographic ranges, whereas species with higher persistence ability more frequently occupy environments outside their ecological niche. Our study thus identifies major demographic and functional determinants of species' niches and geographic distributions. It highlights that the inference of ecological niches from geographical distributions is most problematic for poorly dispersed and highly persistent species. We conclude that the direct quantification of ecological niches from demographic responses to environmental variation is a crucial step toward a better predictive understanding of biodiversity dynamics under environmental change.