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A carbonate chemistry balance module was implemented into a biogeochemical model of the planktonic food web. The model, named Eco3M-CarbOx, includes 22 state variables that are dispatched into 5 compartments: phytoplankton, heterotrophic bacteria, detrital particulate organic matter, labile dissolved organic, and inorganic matter. This model is applied to and evaluated in the Bay of Marseille (BoM, France), which is a coastal zone impacted by the urbanized and industrialized Aix–Marseille Metropolis, and subject to significant increases in anthropogenic emissions of CO2.The model was evaluated over the year 2017, for which in situ data of the carbonate system are available in the study site. The biogeochemical state variables of the model only change with time, to represent the time evolution of a sea surface water cell in response to the implemented realistic forcing conditions. The model correctly simulates the value ranges and seasonal dynamics of most of the variables of the carbonate system except for the total alkalinity. Several numerical experiments were conducted to test the response of carbonate system to (i) a seawater temperature increase, (ii) wind events, (iii) Rhône River plume intrusions, and (iv) different levels of atmospheric CO2 contents. This set of numerical experiments shows that the Eco3M-CarbOx model provides expected responses in the alteration of the marine carbonate balance regarding each of the considered perturbation. When the seawater temperature changes quickly, the behavior of the BoM waters alters within a few days from a source of CO2 to the atmosphere to a sink into the ocean. Moreover, the higher the wind speed is, the higher the air–sea CO2 gas exchange fluxes are. The river intrusions with nitrate supplies lead to a decrease in the pCO2 value, favoring the conditions of a sink for atmosphericCO2 into the BoM. A scenario of high atmospheric concentrations of CO2 also favors the conditions of a sink for atmosphericCO2 into the waters of the BoM. Thus the model results suggest that external forcings have an important impact on the carbonate equilibrium in this coastal area.

Movement is a key behaviour to better understand how individuals respond to their environment. Movement behaviours are affected by both extrinsic factors that individuals face, such as weather conditions, and intrinsic factors, such as sex and experience. Because of the energy costs it entails, movement behaviours can have direct consequences on an individual's demographic parameters—and ultimately on population dynamics. However, the relationship between extrinsic factors, intrinsic factors, daily movement behaviour and demographic parameters such as breeding performance is poorly known, in particular for central place forager territorial species. We investigated here the link between movement behaviours and breeding performance of the French population of Bonelli's eagle ( Aquila fasciata ), a territorial and sedentary long‐lived raptor, and how this link may depend on extrinsic and intrinsic factors. By using data from annual monitoring of breeding performance for the population and GPS tracking of 48 individuals (26 males and 22 females), we found that the breeding performance of this population was mainly driven by whether a new individual was recruited into the territory, and only slightly by weather conditions. Movement behaviours (proportion of time in flight, range of movement and straightness of trajectories) showed large between‐individual variation. Those behaviours were related with weather conditions (wind and rainfall) at a daily scale, as well as with individual's experience. We found only one significant correlation between movements and breeding performance: male Bonelli's eagles spending more time flying during chick‐rearing phase had lower productivity. Movement behaviours and breeding performance were also indirectly linked through individual's experience, with more experienced birds having better breeding success and a shorter range of movement and spent less time in flight. This suggests that experienced individuals progressively acquire knowledge of their breeding territory, are more efficient in finding prey, and adapt their foraging strategies to weather conditions to minimise energy costs, allowing them higher breeding performance.

River landscapes are increasingly viewed as a collection of nested geomorphic features, the hydrological effects of which juxtapose to create a mosaic of aquatic habitat conditions. We examined how the combined hydrological influences of stream reaches and gravel bars affect the composition of hyporheic invertebrate assemblages along the longitudinal and vertical dimensions of river landscapes. We worked in 12 braided-river valley segments of tributaries to the Rhône River, France. Valley segments were bounded downstream by geological knickpoints so that bedform-induced exchange flows beneath gravel bars and riffles were predictably embedded in exchange flows occurring at the valley-segment scale. In upstream reaches (UR) and downstream reaches (DR) of each valley segment, we collected invertebrates at the heads and tails of gravel bars in the hyporheic zone and at the upstream and downstream ends of riffles in surface channels adjacent to the bars. Patterns of vertical hydraulic gradient and specific conductance and the resulting spatial heterogeneity of temperature, dissolved O2, and particulate organic C suggested that DR were points of flow convergence and water mixing. Specific conductance increased and temperature decreased more steeply along gravel bars in DR, indicating that water from long hyporheic flow paths or lateral aquifers was discharging at the tails of bars in DR. Density hotspots for insect larvae corresponded to hyporheic patches at the heads of bars in DR, which received the highest organic matter inputs from localized downwelling of surface water and were not affected by inputs of cold water from hyporheic flow paths or lateral aquifers. Density of epigean taxa at the tails of bars decreased more steeply with depth in DR than in UR, and density of hypogean taxa increased more steeply. Viewing local hyporheic assemblages as the outcome of a series of environmental filters operating over multiple exchange flows induced by nested geomorphic features provides a general framework that may foster our understanding of biodiversity patterns in river landscapes.

Geographical limits of species' distributions are assumed to be coincident with ecological margins, although this assumption might not always be true. Indeed, harsh environments such as Alpine and Mediterranean ecosystems may favour high phenotypic variability among populations, especially those in peripheral sites. Floral traits are often found to be less variable and less affected by environmental heterogeneity than vegetative traits because variation in the former may have negative effects on fitness. For this reason, it is important to quantify variation in floral traits and plant fecundity in study range limits. The objective of the study is to examine phenotypic variation and differences in reproduction in endemic Lilium pomponium in the Maritime and Ligurian Alps in relation to environmental variation across its distribution range. In this species, marginal climatic populations occur both in the peripheral and central geographical locations of the distribution range; hence, geographical and ecological gradients are not concordant. Floral trait variation is related to local environmental conditions with an array of interactions among resource availability, potential pollen limitation and population size that are differentially related to floral traits. Contrary to the general expectation, all central and peripheral populations had similar, moderate seed production with each group limited by different factors acting on different stages of the life-history strategy. Our results are in line with the idea that general expectations are confirmed only when its assumptions are met and that the differences in pollination environment along an environmental gradient may not be the main determinant of the distribution limit.

Here, palaeobotanical and genetic data for common beech (Fagus sylvatica) in Europe are used to evaluate the genetic consequences of long-term survival in refuge areas and postglacial spread. Four large datasets are presented, including over 400 fossil-pollen sites, 80 plant-macrofossil sites, and 450 and 600 modern beech populations for chloroplast and nuclear markers, respectively. The largely complementary palaeobotanical and genetic data indicate that: (i) beech survived the last glacial period in multiple refuge areas; (ii) the central European refugia were separated from the Mediterranean refugia; (iii) the Mediterranean refuges did not contribute to the colonization of central and northern Europe; (iv) some populations expanded considerably during the postglacial period, while others experienced only a limited expansion; (v) the mountain chains were not geographical barriers for beech but rather facilitated its diffusion; and (vi) the modern genetic diversity was shaped over multiple glacial-interglacial cycles. This scenario differs from many recent treatments of tree phylogeography in Europe that largely focus on the last ice age and the postglacial period to interpret genetic structure and argue that the southern peninsulas (Iberian, Italian and Balkan) were the main source areas for trees in central and northern Europe

Numerous freshwater acanthocephalans are able to alter the behaviour of their intermediate hosts to increase their predation risk by final hosts, thereby enhancing trophic transmission between their two hosts. Because temperature is widely expected to impact freshwater host-parasite interactions, we investigated how it can affect movements of both uninfected and Pomphorhynchus laevis-infected Gammarus pulex in an artificial stream in 5 cm/s water flow. We found that P. laevis infection of G. pulex induced both higher frequency and higher amplitude of movements along the artificial stream. Moreover, at warmer temperature (21°C), uninfected and P. laevis-infected G. pulex moved more in the artificial stream than at 15°C. In this regard, warmer temperature could then impact gammarids distribution and increase P. laevis transmission rate toward their definitive host in freshwater ecosystems. Firstly, this study provides new insights into how the key temperature factor influences gammarids species movements in the stream. Secondly, elevated temperature did not influence the intensity of P. laevis manipulation in G. pulex intermediate host. This work highlights that warmer temperature might affect the distribution and the behaviour of infected or uninfected freshwater gammarids with no direct effect on acanthocephalan trophic transmission through manipulation.

QuestionsAre variable effects of different phenotypes of foundation plant species on subordinates across contrasting habitat conditions (with varying stress and disturbance levels) due to either varying environmental conditions or heritable differences in traits between phenotypes? To evaluate the contribution of environmental effects we quantified the effects of contrasting phenotypes of a foundation legume shrub on their subordinate species across exposure (drought stress) and grazing conditions. LocationA sub-alpine xerophytic community of western Mount Lebanon, Lebanon. MethodsFor two phenotypes of the spiny cushion shrub Onobrychis cornuta, a facilitative phenotype that occurs in concave topographies (mesic soil) and a competitive phenotype that occurs in convex topographies (xeric soil), we quantified cushion traits, environmental conditions and subordinate plant species abundances (within and outside the cushions) for the two phenotypes in northern (low stress) and southern (high stress) exposures, and with and without grazing. Relative interaction index (RII) for subordinate species richness and abundance was calculated in the eight treatment combinations and a correspondence analysis (CA) was conducted on species composition. ResultsDrought stress exacerbated phenotypic effects in southern exposure, with loose phenotypes being more facilitative and tight phenotypes more competitive than in northern exposure. This was related to both changes in cushion traits of the two phenotypes and to an increase in the pool of subordinate species sensitive to cushion effects. In contrast, grazing increased cushion positive effects of both phenotypes through the occurrence of indirect facilitation, with loose phenotypes becoming more facilitative and tight phenotypes less competitive. This was due both to changes in cushion traits of the two phenotypes and to their shared spiny phenotype limiting grazing effects. ConclusionsBecause increasing stress from northern to southern exposure did not increase competitive effects of either phenotype, and because the cessation of grazing did not cancel out differences in facilitative effects between phenotypes, neither drought stress nor grazing disturbance appeared to be the main drivers of the observed phenotypic effects on subordinate species across habitats. We conclude that differences in phenotypic effects of this legume shrub are very likely due to heritable differences in traits between phenotypes.

Quantifying variation of genetic traits over the geographical range of species is crucial for understanding the factors driving their range dynamics. The center-periphery hypothesis postulates, and many studies support, the idea that genetic diversity decreases and genetic differentiation increases toward the geographical periphery due to population isolation. The effects of environmental marginality on genetic variation has however received much less attention. We tested the concordance between geographical and environmental gradients and the genetic predictions of center-periphery hypothesis for endemic in the southern Alps. We found little evidence for concordance between genetic variation and both geographical and environmental gradients. Although the prediction of increased differentiation at range limits is met, genetic diversity does not decrease towards the geographical periphery. Increased differentiation among peripheral populations, that are not ecologically marginal, may be explained by a decrease in habitat availability that reduces population connectivity. In contrast, a decrease of genetic diversity along environmental but not geographical gradients may be due to the presence of low quality habitats in the different parts of the range of a species that reduce effective population size or increase environmental constraints. As a result, environmental factors may affect population dynamics irrespective of distance from the geographical center of the range. In such situations of discordance between geographical and environmental gradients, the predictions of decreasing genetic diversity and increasing differentiation toward the geographical periphery may not be respected.

A striking feature of the Mediterranean flora concerns the high rates of narrow endemism within many regions. The prevailing paradigm for the evolution of such endemism relies on an important role of geographic isolation and allopatric speciation. Until recently there has been little work on the precise ecological differences among endemic plants and their congeners in the Mediterranean region and the potential role of ecological specialisation in isolation and speciation. This paper has two objectives. First, we evaluate general ecological differences among endemic and widespread congeners in the flora of the western Mediterranean. The results and review of the literature attest to consistent patterns of ecological differentiation among endemic species and their snore widespread congeners. Second, we present results of a detailed study of morphological, molecular and ecological differentiation in a group of spring-flowering Mediterranean Cyclamen species. This study illustrates how differentiation in geographically peripheral and ecologically marginal populations may contribute to the diversification of endemic species whose contemporary distributions are disjunct from con-generic species.

Background The reconstruction of biological processes and human activities during the last glacial cycle relies mainly on data from biological remains. Highly abundant tissues, such as wood, are candidates for a genetic analysis of past populations. While well-authenticated DNA has now been recovered from various fossil remains, the final 'proof' is still missing for wood, despite some promising studies. Scope The goal of this study was to determine if ancient wood can be analysed routinely in studies of archaeology and palaeogenetics. An experiment was designed which included blind testing, independent replicates, extensive contamination controls and rigorous statistical tests. Ten samples of ancient wood from major European forest tree genera were analysed with plastid DNA markers. Conclusions Authentic DNA was retrieved from wood samples up to 1000 years of age. A new tool for real-time vegetation history and archaeology is ready to use.