The First Occupations of Western Europe: Dispersals and Population Dynamics in the Early to Middle Pleistocene

Population dynamics of the mussel Mytilus edulis: spatial variations in age-class densities of an intertidal estuarine population along environmental gradients

We develop a quantitative theory of mortality and population dynamics, emphasising individuals’ decisions to reduce their mortality by adopting better health technology. Expanded use of this technology reduces the cost of adoption and confers a dynamic externality by increasing the future number of individuals who use the technology. Our model generates a diffusion curve whose shape dictates the pace of mortality reduction. The model explains historical trends in mortality rates and life expectancies at various ages and population dynamics in Western Europe. Unlike Malthusian theories based solely on income, ours is consistent with the observed disconnect between mortality and income. Unlike Beckerian theories of fertility, ours accounts for the observed acceleration in population.

Regional behaviour among late Neanderthal groups in Western Europe: A comparative assessment of late Middle Palaeolithic bifacial tool variability

Few studies have explored population dynamics of species sharing life-history traits and common environmental drivers but living in widely separated regions or continents. Large-scale climate cycles can impact habitats and populations over broad geographic areas and may act as global forces shaping animal population dynamics. We tested for synchronous population dynamics of eight ecologically equivalent duck species in Western Europe (WEU) and central North America (NA) from 1976 to 2019. We investigated the extent to which the Atlantic Multi-Decadal Oscillation (AMO) may have induced shared climatic conditions on the breeding areas of these populations and whether the index was correlated with duck population dynamics. Evidence of annual and long-term population synchrony was assessed by estimating correlation in annual growth rates and population abundances, respectively. Shared (increasing) long-term trends in WEU and NA were found in four species-pairs, but no species-pair had synchronous population growth on an annual basis. Three species-pairs sharing trends were positively correlated with the AMO index which increased during the study period. Positive cycling of the AMO was correlated with increased temperature and precipitation in breeding areas of both continents, which may have produced favorable conditions (earlier springs, more ponds) for some duck populations. Differences in the local effects of weather on environmental conditions and other continent-specific extrinsic factors may mask annual synchrony in the response of continental populations to climate. Potential links between the AMO trends and extrinsic factors such as shared changes in anthropogenic drivers (e.g., climate and land use change) should be addressed in future studies.

The Eurasian mammoth distribution during the second half of the Late Pleistocene and the Holocene: Regional aspects

Uncertainty, robustness, and the value of information in managing an expanding Arctic goose population

Population viability analysis (PVA) has become a basic tool of current conservation practice. However, if not accounted for properly, the uncertainties inherent to PVA predictions can decrease the reliability of this type of analysis. In the present study, we performed a PVA of the whole western European population (France, Portugal, and Spain) of the endangered Bonelli's Eagle ( Aquila fasciata ), in which we thoroughly explored the consequences of uncertainty in population processes and parameters on PVA predictions. First, we estimated key vital rates (survival, fertility, recruitment, and dispersal rates) using monitoring, ringing, and bibliographic data from the period 1990–2009 from 12 populations found throughout the studied geographic range. Second, we evaluated the uncertainty about model structure (i.e., the assumed processes that govern individual fates and population dynamics) by comparing the observed growth rates of the studied populations with model predictions for the same period. Third, using the model structures suggested in the previous step, we assessed the viability of both the local populations and the overall population. Finally, we analyzed the effects of model and parameter uncertainty on PVA predictions. Our results strongly support the idea that all local populations in western Europe belong to a single, spatially structured population operating as a source–sink system, whereby the populations in the south of the Iberian Peninsula act as sources and, thanks to dispersal, sustain all other local populations, which would otherwise decline. Predictions regarding population dynamics varied considerably, and models assuming more constrained dispersal predicted more pessimistic population trends than models assuming greater dispersal. Model predictions accounting for parameter uncertainty revealed a marked increase in the risk of population declines over the next 50 years. Sensitivity analyses indicated that adult and pre‐adult survival are the chief vital rates regulating these populations, and thus, the conservation efforts aimed at improving these survival rates should be strengthened in order to guarantee the long‐term viability of the European populations of this endangered species. Overall, the study provides a framework for the implementation of multi‐site PVAs and highlights the importance of dispersal processes in shaping the population dynamics of long‐lived birds distributed across heterogeneous landscapes.

Population dynamics are governed by the so-called four BIDE processes: birth, immigration, death, and emigration. However, most population models fail to explicitly consider all four processes, which may hinder a comprehensive understanding of how and why populations change over time. The advent of Integrated Population Models (IPMs) and recent developments in spatial mark-recapture models have enabled deeper insights into demography and dispersal. In this study, we merged both kinds of models into a spatially explicit IPM. By integrating count, reproduction, mark-recapture, and dispersal data, this framework permitted the separate modeling of all BIDE processes, which subsequently allowed (1) a fine-scale estimation of population dynamics and (2) the estimation of central population parameters and stages that have traditionally been elusive in demographic studies but are key to applied conservation, such as the long-term dynamics of floaters (sexually mature non-breeders), sink-source status, and dispersal processes. Using this approach, we carried out a fine-scale assessment of the long-term dynamics and demographic drivers of one long-lived Bonelli's eagle population from Western Europe (1986-2020). Our results illustrated a considerable population decline and subsequent recovery alongside multiple demographic insights scarcely documented to date in long-lived species. First, we reported a decrease and subsequent increase in floater numbers probably associated with parallel changes in the breeding population, hence contributing to the scarce empirical knowledge available about the role and dynamics of floaters. Second, we detected a change in average population functioning from a sink to a neutral contributor, thus shedding light on the flexibility and drivers of sink-source dynamics. Third, we underscored the central role of non-breeder survival for population recovery, suggesting that long-lived species conservation action should not only focus on adult or breeding populations, as is typically the case. Fourth, we quantified the magnitudes and variations of local and dispersal processes in the long term and discussed their potential implications in terms of management implementation. Overall, our study highlights the potential of spatially explicit IPMs to build more complete assessments of population dynamics, contribute to better-informed conservation action, and help fill knowledge gaps in ecological sciences.

The Central Balkans region is of great importance for understanding the spread of the Neolithic in Europe but the Early Neolithic population dynamics of the region is unknown. In this study we apply the method of summed calibrated probability distributions to a set of published radiocarbon dates from the Republic of Serbia in order to reconstruct population dynamics in the Early Neolithic in this part of the Central Balkans. The results indicate that there was a significant population growth after ~6200 calBC, when the Neolithic was introduced into the region, followed by a bust at the end of the Early Neolithic phase (~5400 calBC). These results are broadly consistent with the predictions of the Neolithic Demographic Transition theory and the patterns of population booms and busts detected in other regions of Europe. These results suggest that the cultural process that underlies the patterns observed in Central and Western Europe was also in operation in the Central Balkan Neolithic and that the population increase component of this process can be considered as an important factor for the spread of the Neolithic as envisioned in the demic diffusion hypothesis.

BackgroundClimatic and environmental fluctuations as well as anthropogenic pressure have led to the extinction of much of Europe’s megafauna. The European bison or wisent (Bison bonasus), one of the last wild European large mammals, narrowly escaped extinction at the onset of the 20th century owing to hunting and habitat fragmentation. Little is known, however, about its origin, evolutionary history and population dynamics during the Pleistocene.ResultsThrough ancient DNA analysis we show that the emblematic European bison has experienced several waves of population expansion, contraction, and extinction during the last 50,000 years in Europe, culminating in a major reduction of genetic diversity during the Holocene. Fifty-seven complete and partial ancient mitogenomes from throughout Europe, the Caucasus, and Siberia reveal that three populations of wisent (Bison bonasus) and steppe bison (B. priscus) alternately occupied Western Europe, correlating with climate-induced environmental changes. The Late Pleistocene European steppe bison originated from northern Eurasia, whereas the modern wisent population emerged from a refuge in the southern Caucasus after the last glacial maximum. A population overlap during a transition period is reflected in ca. 36,000-year-old paintings in the French Chauvet cave. Bayesian analyses of these complete ancient mitogenomes yielded new dates of the various branching events during the evolution of Bison and its radiation with Bos, which lead us to propose that the genetic affiliation between the wisent and cattle mitogenomes result from incomplete lineage sorting rather than post-speciation gene flow.ConclusionThe paleogenetic analysis of bison remains from the last 50,000 years reveals the influence of climate changes on the dynamics of the various bison populations in Europe, only one of which survived into the Holocene, where it experienced severe reductions in its genetic diversity. The time depth and geographical scope of this study enables us to propose temperate Western Europe as a suitable biotope for the wisent compatible with its reintroduction.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-016-0317-7) contains supplementary material, which is available to authorized users.

A key challenge in the management of populations is to quantify the impact of interventions in the face of environmental and phenotypic variability. However, accurate estimation of the effects of management and environment, in large‐scale ecological research is often limited by the expense of data collection, the inherent trade‐off between quality and quantity, and missing data. In this paper we develop a novel modelling framework, and demographically informed imputation scheme, to comprehensively account for the uncertainty generated by missing population, management, and herbicide resistance data. Using this framework and a large dataset (178 sites over 3 years) on the densities of a destructive arable weed (Alopecurus myosuroides) we investigate the effects of environment, management, and evolved herbicide resistance, on weed population dynamics. In this study we quantify the marginal effects of a suite of common management practices, including cropping, cultivation, and herbicide pressure, and evolved herbicide resistance, on weed population dynamics. Using this framework, we provide the first empirically backed demonstration that herbicide resistance is a key driver of population dynamics in arable weeds at regional scales. Whilst cultivation type had minimal impact on weed density, crop rotation, and earlier cultivation and drill dates consistently reduced infestation severity. Synthesis and applications: As we demonstrate that high herbicide resistance levels can produce extremely severe weed infestations, monitoring herbicide resistance is a priority for farmers across Western Europe. Furthermore, developing non‐chemical control methods is essential to control current weed populations, and prevent further resistance evolution. We recommend that planning interventions that centre on crop rotation and incorporate spring sewing and cultivation to provide the best reductions in weed densities. More generally, by directly accounting for missing data our framework permits the analysis of management practices with data that would otherwise be severely compromised.

BackgroundThe most recent Alu insertions reveal different degrees of polymorphism in human populations, and a series of characteristics that make them particularly suitable genetic markers for Human Biology studies. This has led these polymorphisms to be used to analyse the origin and phylogenetic relationships between contemporary human groups. This study analyses twelve Alu sequences in a sample of 216 individuals from the autochthonous population of Galicia (NW Spain), with the aim of studying their genetic structure and phylogenetic position with respect to the populations of Western and Central Europe and North Africa, research that is of special interest in revealing European population dynamics, given the peculiarities of the Galician population due to its geographical situation in western Europe, and its historical vicissitudes.ResultsThe insertion frequencies of eleven of the Alu elements analysed were within the variability range of European populations, while Yb8NBC125 proved to be the lowest so far recorded to date in Europe.Taking the twelve polymorphisms into account, the GD value for the Galician population was 0.268. The comparative analyses carried out using the MDS, NJ and AMOVA methods reveal the existence of spatial heterogeneity, and identify three population groups that correspond to the geographic areas of Western-Central Europe, Eastern Mediterranean Europe and North Africa. Galicia is shown to be included in the Western-Central European cluster, together with other Spanish populations. When only considering populations from Mediterranean Europe, the Galician population revealed a degree of genetic flow similar to that of the majority of the populations from this geographic area.ConclusionThe results of this study reveal that the Galician population, despite its geographic situation in the western edge of the European continent, occupies an intermediate position in relation to other European populations in general, and Iberian populations in particular. This confirms the important role that migratory movements have had in the European gene pool, at least since Neolithic times. In turn, the MDS and NJ analyses place Galicia within the group comprised of Western-Central European populations, which is justified by the influence of Germanic peoples on the Galician population during the Middle Ages. However, it should also be noted that some of the markers analysed have a certain degree of differentiation, possibly due to the region's position as a 'cul-de-sac' in terms of Iberian population dynamics.

Abstract. Birds are commonly used as an example of the strongly declining farmland biodiversity in Europe. The populations of many species have been shown to suffer from intensification of management, reduction of landscape heterogeneity, and habitat loss and fragmentation. These conditions particularly dominate farmland in the economically well developed countries of Western Europe. Currently, the farmland environment in Central-Eastern Europe is generally more extensive than in Western Europe and a larger proportion of people still live in rural areas; thus generating different conditions for birds living in agricultural areas. Furthermore, the quasi-subsistence farming in much of Central-Eastern Europe has resulted in agricultural landscapes that are generally more complex than those in Western Europe. To protect declining bird populations living in farmland, detailed knowledge on both species and communities is necessary. However, due to scientific tradition and availability of funding, the majority of studies have been carried out in Western Europe. In consequence this provokes a question: are findings obtained in western conditions useful to identify the fate of farmland bird biodiversity in Central-Eastern Europe? Therefore, the major goal of this paper is to highlight some local and regional differences in biodiversity patterns within EU farmland by comparing intensive agricultural landscapes with more extensive ones. More specifically, we aim to outline differences in agricultural landscapes and land use history in the two regions, use farmland birds to provide examples of the differences in species dynamics and species-habitat interactions between the two regions, and discuss possible social and ecological drivers of the differences in the context of biodiversity conservation. Factors governing spatio-temporal dynamics of farmland bird populations may differ in intensive and extensive landscapes as illustrated here using the Grey Partridge Perdix perdix and the Red-backed Shrike Lanius collurio as examples. The unevenness of farmland bird studies distribution across Europe was also presented. We call for more emphasis on pluralism in furthering both pan-European research on farmland bird ecology and conservation strategies. We also highlight some features specific to Central-Eastern Europe that merit consideration for the more efficient conservation of farmland birds and farmland biodiversity across Europe.

Management strategies for fisheries species require understanding their connectivity and population dynamics. The Brazilian slipper lobster, Scyllarides brasiliensis, is one of the most commercially important slipper lobster species in South America. We investigated, for the first time, the population genetic structure and evolutionary history of this species. Analyses of sequences of the cytochrome oxidase I gene (COI) and the control region (CR) did not reveal any significant genetic structure of S. brasiliensis (N = 202) along 2700 km of the Atlantic coast (COI: FST = 0.0004, FCT = 0–0.005, P > 0.05; CR: FST = 0.004, FCT = 0–0.029, P > 0.05). The genetic homogeneity found suggests high levels of gene flow along the area that are possibly related to the high dispersal potential of the planktonic larvae of the species. Furthermore, the data indicate that demographic and geographical expansions of this slipper lobster population have occurred during the late and middle Pleistocene, which could be related to the fluctuating environmental conditions of that period.

The lengths of fossil leaves of Nothofogus cunninghamii, and of closely related fossil species from sediments older than the Middle Pleistocene showed greater variation than fossil leaves from younger sediments and extant leaves from modern sediment samples and forest floor litter. Leaf sizes of samples of the other two extant evergreen species of Nothofagus subgenus Lophazonia, N. moorei and N.menziesii, were no more variable than modern N.cunninhamii. Leaf lengths of modern and Middle-Late Pleistocene N. cunninhamii and of modern N. menziesii were more or less unimodal in distribution, whereas the leaves of N. moorei follow bimodal distributions, and leaves from the Early Pleistocene Regatta Point and the Oligocene Link- Rapid River sediments tended to be bimodal and highly variable. Leaf lengths from the Oligo-Miocene Monpeelyata sediments were also highly variable, but the sample size was too small to determine if they follow bimodal distributions. The bimodality and high variability in the older sites are unlikely to have been due to taphonomic processes. Thus, within population variability appears to have declined during the Late Tertiary-Early Pleistocene, although the presence of cryptic species in the fossil record could also explain the results. Both a decline in variability within species, and the extinction of Nothofugus species, are consistent with a well documented Late Cainozoic decline in rainforest diversity in Tasmania. Log transformed leaf lengths of modern forest floor litter samples of N. cunninhamii were Strongly correlated with climatic parameters, particularly summer temperature, suggesting that this parameter is a strong determinant of leaf size in N. cunninhamii Changes in N. cunninhamii leaf lengths within Middle Pleistocene sediments were associated with floristic changes interpreted as transitions in glacial/interglacial cycles but these changes were small compared with changes predicted Iron climatic correlation of extant samples, probably because of limited Emetic variability in local populations at the time of deposition.