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Biological invasions pose a rapidly expanding threat to the persistence, functioning and service provisioning of ecosystems globally, and to socio‐economic interests. The stages of successful invasions are driven by the same mechanism that underlies adaptive changes across species in general—via natural selection on intraspecific variation in traits that influence survival and reproductive performance (i.e., fitness). Surprisingly, however, the rapid progress in the field of invasion science has resulted in a predominance of species‐level approaches (such as deny lists), often irrespective of natural selection theory, local adaptation and other population‐level processes that govern successful invasions. To address these issues, we analyse non‐native species dynamics at the population level by employing a database of European freshwater macroinvertebrate time series, to investigate spreading speed, abundance dynamics and impact assessments among populations. Our findings reveal substantial variability in spreading speed and abundance trends within and between macroinvertebrate species across biogeographic regions, indicating that levels of invasiveness and impact differ markedly. Discrepancies and inconsistencies among species‐level risk screenings and real population‐level data were also identified, highlighting the inherent challenges in accurately assessing population‐level effects through species‐level assessments. In recognition of the importance of population‐level assessments, we urge a shift in invasive species management frameworks, which should account for the dynamics of different populations and their environmental context. Adopting an adaptive, region‐specific and population‐focused approach is imperative, considering the diverse ecological contexts and varying degrees of susceptibility. Such an approach could improve and refine risk assessments while promoting mechanistic understandings of risks and impacts, thereby enabling the development of more effective conservation and management strategies. [ABSTRACT FROM AUTHOR]

Considering local population dynamics and dispersal is crucial to project species' range adaptations in changing environments. Dynamic models including these processes are highly computer intensive, with consequent restrictions on spatial extent and/or resolution.We present CATS, an open‐source, extensible modelling framework for simulating spatially and temporarily explicit population dynamics of plants. It can be used in conjunction with species distribution models, or via direct parametrisation of vital rates and allows for fine‐grained control over the demographic and dispersal processes' models.The performance and flexibility of CATS is exemplified (i) by modelling the range shift of four plant species under three future climate scenarios across Europe at a spatial resolution of 100 m., and (ii) by exploring consequences of demographic compensation for range expansion on artificial landscapes.The presented software attempts to leverage the availability of computational resources and lower the barrier of entry for large‐extent, fine‐resolution simulations of plant range shifts in changing environments. [ABSTRACT FROM AUTHOR]

The impact of factors such as density dependence, food availability and weather are known to be important for predicting population change in a wide range of species. However, a challenge in ecology is understanding the contributory and interactive role of these drivers on populations. This is necessary to design effective conservation and management strategies. Using data from long‐term studies of five hazel dormouse Muscardinus avellanarius populations in Europe, we tested the relationship between population density and weather and their impact on demographic rates. We used an integrated population modelling approach, estimating age‐specific overwinter survival, annual population growth and fecundity rates. We found strong negative effects of population density, precipitation and winter temperature on population growth rates. This suggests that warmer and wetter weather negatively affects dormouse survival for both adults and juveniles, but we found subtle differences in these effects between age classes. We also identified an interaction between weather measures and population density on age‐specific survival, possibly as a result of weather impacts during hibernation. Although we found low winter temperature was positively associated with population growth, we found evidence consistent with density dependence. We discuss our results in the context of woodland habitat conservation management. [ABSTRACT FROM AUTHOR]

Aim: Many species experienced population turnover and local extinction during the Late Pleistocene. In the case of megafauna, it remains challenging to disentangle climate change and the activities of Palaeolithic hunter‐gatherers as the main cause. In contrast, the impact of humans on rodent populations is likely to be negligible. This study investigated which climatic and/or environmental factors affect the population dynamics of the common vole. This temperate rodent is widespread across Europe and was one of the most abundant small mammal species throughout the Late Pleistocene. Location: Europe. Taxon: Common vole (Microtus arvalis). Methods: We generated a dataset comprised of 4.2 kb long fragment of mitochondrial DNA (mtDNA) from 148 ancient and 51 modern specimens sampled from multiple localities across Europe and covering the last 60 thousand years (ka). We used Bayesian inference to reconstruct their phylogenetic relationships and to estimate the age of the specimens that were not directly dated. Results: We estimated the time to the most recent common ancestor of all last glacial and extant common vole lineages to be 90 ka ago and the divergence of the main mtDNA lineages present in extant populations to between 55 and 40 ka ago, which is earlier than most previous estimates. We detected several lineage turnovers in Europe during the period of high climate variability at the end of Marine Isotope Stage 3 (MIS 3; 57–29 ka ago) in addition to those found previously around the Pleistocene/Holocene transition. In contrast, data from the Western Carpathians suggest continuity throughout the Last Glacial Maximum (LGM) even at high latitudes. Main Conclusions: The main factor affecting the common vole populations during the last glacial period was the decrease in open habitat during the interstadials, whereas climate deterioration during the LGM had little impact on population dynamics. This suggests that the rapid environmental change rather than other factors was the major force shaping the histories of the Late Pleistocene faunas. [ABSTRACT FROM AUTHOR]

Puumala orthohantavirus (PUUV) is the most important hantavirus species in Europe, causing the majority of human hantavirus disease cases. In central and western Europe, the occurrence of human infections is mainly driven by bank vole population dynamics influenced by beech mast. In Germany, hantavirus epidemic years are observed in 2‐ to 5‐year intervals. Many of the human infections are recorded in summer and early autumn, coinciding with peaks in bank vole populations. Here, we describe a molecular epidemiological investigation in a small company with eight employees of whom five contracted hantavirus infections in late 2017. Standardized interviews with employees were conducted to assess the circumstances under which the disease cluster occurred, how the employees were exposed and which counteractive measures were taken. Initially, two employees were admitted to hospital and serologically diagnosed with hantavirus infection. Subsequently, further investigations were conducted. By means of a self‐administered questionnaire, three additional symptomatic cases could be identified. The hospital patients' sera were investigated and revealed in one patient a partial PUUV L segment sequence, which was identical to PUUV sequences from several bank voles collected in close proximity to company buildings. This investigation highlights the importance of a One Health approach that combines efforts from human and veterinary medicine, ecology and public health to reveal the origin of hantavirus disease clusters. [ABSTRACT FROM AUTHOR]

Many mammalian species use photoperiod as a predictive cue to time seasonal reproduction. In addition, metabolic effects on the reproductive axis may also influence seasonal timing, especially in female small, short‐lived mammals. To get a better understanding of how annual cycling environmental cues impact reproductive function and plasticity in small, short‐lived herbivores with different geographic origins, we investigated the mechanisms underlying integration of temperature in the photoperiodic‐axis regulating female reproduction in a Northern vole species (tundra vole, Microtus oeconomus) and in a Southern vole species (common vole, Microtus arvalis). We show that photoperiod and temperature interact to determine appropriate physiological responses; there is species‐dependent annual variation in the sensitivity to temperature for reproductive organ development. In common voles, temperature can overrule photoperiodical spring‐programmed responses, with reproductive organ mass being higher at 10°C than at 21°C, whereas in autumn they are less sensitive to temperature. These findings are in line with our census data, showing an earlier onset of spring reproduction in cold springs, while reproductive offset in autumn is synchronized to photoperiod. The reproductive organs of tundra voles were relatively insensitive to temperature, whereas hypothalamic gene expression was generally upregulated at 10°C. Thus, both vole species use photoperiod, whereas only common voles use temperature as a cue to control spring reproduction, which indicates species‐specific reproductive strategies. Due to global warming, spring reproduction in common voles will be delayed, perhaps resulting in shorter breeding seasons and thus declining populations, as observed throughout Europe. [ABSTRACT FROM AUTHOR]

This study quantifies the processes involved in regulating the European eel population of Lough Neagh, a lake in Northern Ireland. The relationship between glass eel input and silver eel output for the 1923–1997 cohorts was best described by a Beverton–Holt stock recruitment model. Glass eel input time series was not complete and was thus derived from the relationship between catches elsewhere in Europe and Lough Neagh, together with the addition of stocked glass eel. Silver eel output was the sum of silver eel escapement, catch and yellow eel catch converted to silver eel equivalents. Natural mortality increased with glass eel density, ranging from 0.017 to 0.142 year−1. The mean carrying capacity increased from ≈3.25 M silver eels (≈26 kg ha−1) for the 1923–1943 cohorts to ≈5.0 M (≈40 kg ha−1) for the 1948–1971 cohorts before regressing back to ≈3.25 M. The total silver eel output was highest during the late 1970s/early 1980s at 35–45 kg ha−1 year−1 and lowest during the early years of the 20th century and is currently at 10–15 kg ha−1 year−1. The findings are discussed in relation to (a) the ecological changes that have occurred within the lough, associated with eutrophication and the introduction of roach (Rutilus rutilus L.), and (b) the decline of the wider European eel stock across its distribution range. The findings from this study have relevance for the wider management of the European eel stock. [ABSTRACT FROM AUTHOR]

Analysis of fertility trends along urban gradients contributes to assess socio‐demographic change at larger scales and the new geography of metropolitan growth at smaller scales. At larger scales, urban fertility was systematically lower than rural fertility; at smaller scales, suburbs were found to have higher fertility than central districts and the neighbouring rural areas. However, fertility divides have rarely been re‐contextualised in a long‐term perspective, considering the influence of exogenous factors that change over time with urban cycles. Assuming that spatial fertility variations are contextual to the development stage of a given region, the present study goes beyond the traditional 'urban‐suburban‐rural' divide and provides a long‐term vision that integrates small‐scale fertility variations and city life cycles. The study investigates spatial trends in a fertility index along a cycle from urbanisation to re‐urbanisation in a low‐fertility European context (Athens, Greece) using a multi‐scale analysis framework. The empirical findings of this study demonstrate that rural fertility was systematically lower than urban fertility apart from a short time interval (1950s). Fertility in urban locations was the highest during earlier stages of urbanisation. In suburban locations, fertility increased during late suburbanisation, stabilising (or declining slightly) with counter‐urbanisation. Re‐urbanisation was associated with a greater spatial heterogeneity in fertility rates. By documenting a differential response of fertility to urban cycles, our study re‐frames the relationship between natural population dynamics and metropolitan transitions, concluding that regional fertility divides are temporary outcomes of a specific ensemble of socio‐economic forces underlying a given urban model. [ABSTRACT FROM AUTHOR]

The ability for vegetative growth and development of generative organs often reflects an adaptation to the environment and may be a suitable proxy for understanding population dynamics of rare relict species. An example of such a plant is Carex lachenalii Schkuhr, an arctic-alpine species, in the temperate zone of Europe only occurring in isolated localities of high-elevation mountain ranges. We aimed to assess whether there were relationships between flower production and clonal growth of C. lachenalii, both at the tuft and plot level, and how co-occurring vegetation could modify this relationship. In the study we focused on population-level traits of C. lachenalii, vegetation traits and components of functional diversity. At the tuft level we found that the proportion of flowering ramets of C. lachenalii decreased with increasing diameter of the tuft. At the plot level, in snowbed vegetation C. lachenalii produced more flowering ramets. We suggest this is due to higher environmental stress, expressed by high importance of habitat filtering (low functional dispersion) in shaping species composition of co-occurring vegetation. In granite grasslands and milder environment (expressed by higher functional dispersion), C. lachenalii produced more vegetative ramets, which we suggest is a result of a more competitive environment. While in snowbeds investment in flowering ramets could promote successful persistence of C. lachenalii, survival of subpopulations occurring in the highly competitive conditions of granite grasslands may be uncertain due to potentially weak adaptation to competition with graminoids and dwarf shrubs. [ABSTRACT FROM AUTHOR]

Aim The aim was to assess the sensitivity of butterfly population dynamics to variation in weather conditions across their geographical ranges, relative to sensitivity to density dependence, and determine whether sensitivity is greater towards latitudinal range margins. Location Europe. Time period 1980-2014. Major taxa studied Butterflies. Methods We use long-term (35 years) butterfly monitoring data from > 900 sites, ranging from Finland to Spain, grouping sites into 2° latitudinal bands. For 12 univoltine butterfly species with sufficient data from at least four bands, we construct population growth rate models that include density dependence, temperature and precipitation during distinct life-cycle periods, defined to accommodate regional variation in phenology. We use partial R2 values as indicators of butterfly population dynamics' sensitivity to weather and density dependence, and assess how these vary with latitudinal position within a species' distribution. Results Population growth rates appear uniformly sensitive to density dependence across species' geographical distributions, and sensitivity to density dependence is typically greater than sensitivity to weather. Sensitivity to weather is greatest towards range edges, with symmetry in northern and southern parts of the range. This pattern is not driven by variation in the magnitude of weather variability across the range, topographic heterogeneity, latitudinal range extent or phylogeny. Significant weather variables in population growth rate models appear evenly distributed across the life cycle and across temperature and precipitation, with substantial intraspecific variation across the geographical ranges in the associations between population dynamics and specific weather variables. Main conclusions Range-edge populations appear more sensitive to changes in weather than those nearer the centre of species' distributions, but density dependence does not exhibit this pattern. Precipitation is as important as temperature in driving butterfly population dynamics. Intraspecific variation in the form and strength of sensitivity to weather suggests that there may be important geographical variation in populations' responses to climate change. [ABSTRACT FROM AUTHOR]

Long distance dispersal (LDD) of propagules is an important determinant of population dynamics, community structuring and biodiversity distribution at landscape, and sometimes continental, scale. Although migratory animals are potential LDD vectors, migratory movement data have never been integrated in estimates of propagule dispersal distances and LDD probability. Here we integrated migratory movement data of two waterbird species (mallard and teal) over two continents (Europe and North America) and gut retention time of different propagules to build a simple mechanistic model of passive dispersal of aquatic plants and zooplankton. Distance and frequency of migratory movements differed both between waterbird species and continents, which in turn resulted in changes in the shapes of propagule dispersal curves. Dispersal distances and the frequency of LDD events (generated by migratory movements) were mainly determined by the disperser species and, to a lesser extent, by the continent. The gut retention time of propagules also exerted a significant effect, which was mediated by the propagule characteristics (e.g. seeds were dispersed farther than Artemia cysts). All estimated dispersal curves were skewed towards local-scale dispersal and, although dispersal distances were lower than previous estimates based only on the vector flight speed, had fat tails produced by LDD events that ranged from 230 to 1209 km. Our results suggest that propagule dispersal curves are determined by the migratory strategy of the disperser species, the region (or flyway) through which the disperser population moves, and the propagule characteristics. Waterbirds in particular may frequently link wetlands separated by hundreds of kilometres, contributing to the maintenance of biodiversity and, given the large geographic scale of the dispersal events, to the readjustment of species distributions in the face of climate change. [ABSTRACT FROM AUTHOR]

In the context of global changes, defining the source-sink dynamics of populations of emblematic species, such as seabirds, within the limits of their distribution range is often crucial to optimize the priorities of surveys and conservation management, especially in protected areas. However, ringing is often not possible and only simple survey methods, such as the 'apparently occupied sites' method, can be utilized by managers of protected areas and threatened species. Using data collected between 1997 and 2005, we investigated the population dynamics of the northern fulmar ( Fulmarus glacialis) at the southern limit of its range on the western French coast, which hosts increasing populations. Using a robust design spatial occupancy model, we estimated the proportion of occupied nests, the rates of nest colonization, nest extinction and the population growth rates of four colonies of the largest population (Ouessant Island). The estimated annual growth rate was high (average 1.049). A deterministic population dynamics model indicated that the observed rapid increase of Ouessant populations cannot be explained by their intrinsic dynamics, which suggested an important role for immigration. Different demographic scenarios provide several lines of evidence that the large northern fulmar population in this Man and Biosphere Reserve is a sink population. The strong increase in a population located at the limits of the species distributional range implies that it functions as a population sink. Inexpensive effective survey methods could allow investigation of the demographic status of seabird populations and provide relevant information for the hierarchization of conservation priorities. [ABSTRACT FROM AUTHOR]

Populations at the margin of geographic ranges of distribution have been considered more vulnerable than central ones, but recent reviews have caste doubt on this generalization. We examined the reproductive and demographic performance of a rare Euroasiatic orchid (Cypripedium calceolus) at its southwesterly range limit and compared our findings with those of previous studies of nine central populations at the center of the orchid's range. We sought to test the central-marginal model and to evaluate factors involved in long-term performance of forest Eurosiberian species with peripheral populations in southern European mountains. We characterized (structure, temporal fluctuations, herbivory, reproductive success, and recruitment at different habitats) four Pyrenean populations of C. calceolus of different sizes (5-3500 ramets) and monitored three of them for up to 13 years. Two quantitative stochastic models (count data and matrix models) were used to assess population trends and viability and the effect of herbivory. Contrary to expectations, and despite the negative effect of sporadic events of herbivory, the peripheral populations we studied (except the smallest one) performed similarly or better than populations occurring in central part of the species' range in terms of reproductive success and population growth rates. Landscape changes over the last 50 years suggest that natural reforestation could be involved in the success of this plant at its southern limit. Forest expansion in the mountain regions of southern Europe may provide new opportunities for plants with geographic distributions centered mainly at higher latitudes and give some hope for their recovery in future scenarios dominated by biodiversity loss. [ABSTRACT FROM AUTHOR]

Cyclic parthenogenesis, the alternation of parthenogenetic and sexual reproduction, can lead to a wide scope of population structures, ranging from almost monoclonal to genetically highly diverse populations. In addition, sexual reproduction in aquatic cyclic parthenogens is associated with the production of dormant stages, which both enhance potential gene flow among populations as well as impact local evolutionary rates through the formation of dormant egg banks. Members of the cladoceran genus Daphnia are widely distributed key organisms in freshwater habitats, which mostly exhibit this reproduction mode. We assessed patterns of genetic variation within and among populations in the eurytopic and morphologically variable species Daphnia longispina, using data from both nuclear (13 microsatellite loci) and mitochondrial (partial sequencing of the 12S rRNA gene) markers from a set of populations sampled across Europe. Most populations were characterized by very high clonal diversity, reflecting an important impact of sexual reproduction and low levels of clonal selection. Among-population genetic differentiation was very high for both nuclear and mitochondrial markers, and no strong pattern of isolation by distance was observed. We also did not observe any substantial genetic differentiation among traditionally recognized morphotypes of D. longispina. Our findings of high levels of within-population genetic variation combined with high among-population genetic differentiation are in line with predictions of the monopolization hypothesis, which suggests that in species with rapid population growth and potential for local adaptation, strong priority effects due to monopolization of resources lead to reduced levels of gene flow. [ABSTRACT FROM AUTHOR]

1 The western corn rootworm Diabrotica virgifera virgifera LeConte is a major insect pest of field maize, Zea mays L. Larvae can cause substantial injury by feeding on maize roots. Larval feeding may destroy individual roots or root nodes, and reduce plant growth, stability, and yield. Costs associated with managing corn rootworms in continuous maize are annually one of the largest expenditures for insect management in the United States Corn Belt. 2 Even though D. virgifera virgifera has been studied intensively for over 50 years, there is renewed interest in the biology, ecology, and genetics of this species because of its ability to rapidly adapt to management tactics, and its aggressive invasive nature. 3 This article provides a comprehensive review of D. virgifera virgifera population dynamics, specifically: diapause, larval and adult development, seasonality, spatial and temporal dynamics at local and landscape scales, invasiveness in North America and Europe, and non-trophic interactions with other arthropods. 4 Gaps in current knowledge are identified and discussed especially within the context of challenges that scientists in North America and Europe are currently facing regarding pest dynamics and the need to develop appropriate management strategies for each geographic area. [ABSTRACT FROM AUTHOR]

1. The occurrence of different species of seal (Phocidae) during the Holocene in north-eastern Europe was influenced by a changing geological situation over the last 12 000 years, characterized by alternating freshwater, brackish and marine stages and by spatially and temporally limited opportunities for migration of marine species into the Baltic basin. The patterns of immigration by ringed seal Phoca hispida, harp seal Phoca groenlandica, grey seal Halichoerus grypus and harbour seal Phoca vitulina are reviewed here in order to understand present distributions and population sizes. Furthermore, the future of their populations is analysed. 2. Phoca hispida immigrated into the Baltic basin during its brackish Yoldia Stage at the Late Glacial/Early Holocene boundary and has persisted in some disjunct populations until now. A second immigration followed at the beginning of the Littorina Transgression – which resulted in the present stage of the Baltic Sea, obviously caused by the strong cooling event that occurred 6200 calibrated 14C years BC. Its present status is not threatened, but global warming will restrict suitable habitat. 3. Phoca groenlandica had a mid-Holocene intermezzo in the Baltic Sea. Its later disappearance was probably caused by hunting of subadult animals by humans. 4. Halichoerus grypus and Phoca vitulina also immigrated at the beginning of the present stage of the Baltic Sea. Whereas H. grypus has been common from this beginning point until modern times, the population of P. vitulina persisted at a low level for millennia. Only since the 18th century has its population increased and spread over the whole Baltic Sea. [ABSTRACT FROM AUTHOR]

1. Opinions differ as to whether declining species are most likely to survive in central or peripheral parts of their distributions. The former pattern is likely to be driven by high extinction risks in peripheral areas; the latter by gradients of extinction risk. 2. At a continental scale of analysis, the declining butterfly Euphydryas aurinia survived best in southern and eastern countries within Europe. This was statistically associated with geographical variation in agricultural intensification. At this scale of analysis, there was a gradient of survival, caused by a gradient of agricultural intensification. 3. Within England and Wales, survival was greatest in population concentrations, or core areas; that is in 10-km grid squares that were surrounded by other 10-km grid squares that also contained populations of E. aurinia. In the English county of Dorset, populations were also most likely to be found in core areas; that is in habitat patches that were close to other populated habitat patches. 4. In this system, there is support for two patterns of decline. At a coarse scale, there is a geographical gradient of habitat degradation, associated with agricultural intensification. But within a region where decline has taken place, populations survive best in core areas, where aggregations of habitat support viable metapopulation dynamics. 5. Large-scale geographical patterns of decline towards the periphery (or other locations within) the distribution of a species do not negate the validity of conservation strategies based on core-margin population dynamic principles. Core areas within each country or region represent appropriate targets for conservation action. [ABSTRACT FROM AUTHOR]

Mark–recapture data are used to investigate the impact of an exceptional winter flood on the population dynamics of an isolated bearded tit Panurus biarmicus population in north-west England. Adult numbers increased threefold (from 60 to 180 individuals) between 1992 and 2000, but declined by 94% during 2000/2001. This large reduction in numbers was caused by severe over-winter mortality associated with a prolonged flood of the Phragmites litter layer, the main winter foraging habitat of bearded tits, followed immediately by cold weather. At the end of the flood, bearded tits were 20% lighter than during previous winters. Population changes in other years were accurately predicted by annual variation in recruitment, and there was evidence that recruitment was higher following the introduction of artificial nest boxes and was density dependent. This study highlights the potential threat to bearded tits in Europe of predicted increases in the frequency and extent of winter flooding, and the potential utility of measures like artificial nest boxes that aim to promote recruitment. Recent extensions of methodology now permit a detailed exploration of animal population dynamics from mark–recapture data alone. [ABSTRACT FROM AUTHOR]

1. Deer numbers have increased dramatically throughout Europe and North America over the last century, but empirical analyses of variation in harvesting and the influence of biological and cultural factors are lacking. 2. We examined trends in size and composition of red deer Cervus elaphus harvests over the last three to four decades in 11 European countries with contrasting deer productivity, management strategies and hunting traditions. 3. The harvest increased exponentially in all countries except Austria and Germany, where it was stable, and Poland, where it has declined in recent years. Harvest growth rates ranged from 0·009 in Austria to 0·075 in Sweden and depended on the management system and harvest composition, being negatively related to the proportion of females in the adult harvest. 4. Within four focal countries (France, Hungary, Norway and Scotland), there was considerable spatial variation in harvest growth rates. These tended to be higher in recently colonized areas than in traditional hunting areas and were often higher than the maximum possible population growth rate. Range expansion was an important component of the increase in total harvest in France and Scotland, but not in Hungary or Norway. 5. Harvest composition was available for seven countries, all of which showed a strong increase in the proportion of calves in the harvest. The sex ratio of the adult harvest was relatively stable, being strongly male-biased in Norway and marginally female-biased elsewhere. The proportion of males in the harvest was unrelated to trophy hunting objectives. 6. Synthesis and applications. Our study emphasizes that cultural aspects of management need to be accounted for, as well as biological factors, when interpreting the patterns of harvest growth and composition across Europe. Widespread sustained harvest growth has occurred, suggesting continued growth of deer populations with consequent social and economic impacts. Population control is therefore a major challenge for the future, currently hampered by inadequate population data and a decreasing number of hunters in some countries. Increasing the motivation of hunters to harvest female deer is one possible solution, although this may conflict with hunting traditions and economic considerations in some areas. [ABSTRACT FROM AUTHOR]

The western corn rootworm ( Diabrotica virgifera virgifera LeConte, Col.; Chrysomelidae) is an alien invasive species in Europe. It is a univoltine species with eggs that overwinter in the soil and larvae that hatch in spring. Three larval instars feed on maize roots, which can cause plant lodging and yield loss of economic importance. Adults emerge between mid-June and early August and can reduce yields through intensive silk feeding. In order to provide a thorough understanding of the population dynamics of this invasive pest species in the invaded European region, complete age specific life-tables were constructed in two maize fields in southern Hungary assessing the significance of natural mortality factors acting on D. v. virgifera populations. This information provides a rational basis for devising sustainable integrated pest management programmes, in particular, by enabling the identification of vulnerable pest age intervals for the timely application of various management tools. The life-table for D. v. virgifera in Europe resulted in a total mortality of about 99% from the egg stage in the autumn to the emergence of adult females in the following year ( KTotal = 2.48), which is comparable with North America. The highest reduction of D. v. virgifera numbers resulted from the mortality in first instar larvae (94% marginal death rate) and from the unrealized fecundity (80%). However, only the variation in mortality between years can change the generational mortality and thus influence population growth. High variation in the marginal death rate between fields and years was found in the second and third instar larval stages, and in the overwintering egg stage. These mortality factors therefore have the potential to cause changes in the total generational mortality. Furthermore, the life-table suggested that a high fecundity could compensate for a high generational mortality and would lead to population increase. [ABSTRACT FROM AUTHOR]

The possible negative consequences of current low fertility levels are causing increasing concern, particularly in countries where the total fertility rate is below 1.5. Social inertia and self-reinforcing processes may make it difficult to return to higher levels once fertility has been very low for some time, creating a possible “low-fertility trap.” Policies explicitly addressing the fertility-depressing effect of increases in the mean age at child-bearing (the tempo effect) may be a way to raise period fertility to somewhat higher levels and help escape the “low-fertility trap” before it closes. Reforms in the school system may affect the timing of childbearing by lowering the age at completion of education. A more efficient school system, which provides the same qualifications with a younger school-leaving age, is potentially capable of increasing period fertility and hence exerting a rejuvenating effect on the age composition, even if the levels of cohort fertility remain unchanged. Such policies may also have a positive effect on completed cohort fertility. [ABSTRACT FROM AUTHOR]

1. We tested the hypothesis that the bottom-up influence of coniferous plant resources promotes the probability of outbreak or eruptive dynamics in sawflies. The literature was examined for three geographical regions − North America north of Mexico, Europe and Japan.2. In each region tenthredinid sawflies (Hymenoptera: Tenthredinidae) were significantly more likely to be eruptive on conifers than on angiosperms.3. The diprionid sawflies (Hymenoptera: Diprionidae) that attack conifers exclusively showed a significantly higher probability of eruptive dynamics than the tenthredinid sawflies on angiosperms in two regions, North America and Europe, and in Japan the trend was in the same direction.4. The probability of species showing eruptive dynamics on coniferous hosts was not significantly different among tenthredinids and diprionids on conifers in North America, Europe and Japan.5. The weight of evidence supports the hypothesis of conifers supporting a higher percentage of eruptive species than angiosperms.6. In the adaptive radiation of tenthredinid sawflies from flowering plants onto conifers, larches (Larix) appear to be particularly favourable for colonization, but pines (Pinus) have not been colonized in any region, a pattern likely to be explained by the growth characteristics of the host plants.7. Among tenthredinid species in Europe, where sawfly/host relationships are best known, there is a significant trend for an increasing proportion of outbreaking species from herbs, to shrubs, to trees.8. The results indicate for the first time the strong bottom-up effects of plant resources on the population dynamics of sawflies, involving general features of host plant taxa and growth characteristics.Journal of Animal Ecology(2005)doi: 10.1111/j.1365-2656.2005.00935.x [ABSTRACT FROM AUTHOR]

Journal of Animal Ecology (2004) 73, 167–178 [ABSTRACT FROM AUTHOR]

Inducing a decrease in the average age of childbearing in Europe has been suggested as a means to effect population dynamics by slowing population decline and aging. On the other hand, stable population theory suggests that under conditions of subreplacement fertility, longer generation length would imply slower shrinking, and thus produce a larger population in the long run. Consequences of changing the mean length of generation would only show up in the longer run. This assessment, however, does not yield to consequences of possible policies aimed at influencing the mean age of childbearing. The article compares the relative importance of these two effects analytically and with actual data derived from population surveys from the European Union.

Summary 1. Hares are considered to be a valuable game species in most European countries. Hunting needs to be sustainable and sound management of hare populations requires some knowledge of the species’ demographic variability, especially regarding the breeding output, which is highly time- and space-dependent and may govern the population size and exploitability. 2. Using shooting bag analysis and placental scar counts, mean fecundity and leveret survival were estimated at four study sites with contrasting hare numbers and density trends. These demographic parameters, harvest rates and adult natural survival rates (from the literature) were incorporated into a matrix projection model to analyse the population growth rate (λ) sensitivity and to derive indices of sustainable harvest rate (ISHR, i.e. rates compatible with λ≥ 1). 3. The age structure comprised 48–69% young; fecundity varied between 12·2 and 15·0 leverets per breeding female; and 85–100% of adult females bred. These data combined gave a birth-to-autumn leveret survival index of 0·14–0·29 and, when loaded into the matrix model, resulted in simulated λs that matched the density changes observed in the study areas. The model structure, although simple, accounted for most of the relevant biological information. 4. ISHR was 30% when derived iteratively as a function of mean values of those parameters with largest elasticities (leveret survival and doe fecundity). When environmental and demographic stochasticity were included in the model, the proportion of endangered trajectories where the density threshold was < 1 km2 over 50 km2 varied sharply, with small changes in harvest rate or initial population size. Small populations could only sustain ≤ 20% harvest rates. 5. Demographic parameters derived from killed animals during year t can be used a posteriori to understand the species’ dynamics and as... [ABSTRACT FROM AUTHOR]

Minnows Phoxinus phoxinus, studied 30 years after the first record of the species in the subalpine Lake Øvre Heimdalsvatn, Norway, ≥55 mm LT, were estimated to have densities ofc . 4·7 kg ha−1 (120 000 fish) in June 1999 and 2·1 kg ha−1 (63 000 fish) in June 2000. The population was characterized by low individual growth, delayed age of maturity and lived longer when compared to values reported in a previous study in the early phase of its establishment, and other values reported in the literature. Most minnows reached sexual maturity at 4–5 years and >55 mm LT. Although the estimated annual survival of minnows >55 mm was low (S=0·2), ages up to 13 years were recorded. Despite a moderate increase in the population size during the last 20 years, the present reduction in individual growth, followed by delayed age of maturity, suggested the existence of density-dependent effects on the population dynamics of the minnows. The minnows were restricted to the littoral zone and near bottom areas. A vertical or horizontal expansion in habitat use was probably prevented by the presence of piscivorous brown trout Salmo trutta. Copyright 2002 The Fisheries Society of the British Isles. Published by Elsevier Science Ltd. All rights reserved. [Copyright &y& Elsevier]

Summary Using long-term data sets from two lowland floodplain forest bank vole populations in central Europe, we tested two predictions that with increasing densities: (i) proportions of nonparous females in winter populations would increase; and (ii) age of both nonparous and parous females would increase. These two predictions follow from the assumption that changes in age structure are driven by density-dependent shifts in age at first reproduction. Both populations were sampled by snap trapping between 1956 and 1976. For each year, we examined samples of animals collected between November and April for proportions of females with and without breeding experience and analysed their variation in age relative to the population density. The presence or absence of placental scars was used to discriminate between the parous and nonparous animals. Age was determined by measuring the length of the first mandibular molar (M1 ) roots. Both populations exhibited multi-annual fluctuations in numbers closely resembling those in northern Fennoscandia. The proportion of nonparous females in our total sample was 0.73, suggesting that it is uncommon for parous female bank voles to breed in two successive years and that their life histories are largely designed for breeding in one season only as a major reproductive strategy. Using a logistic-binomial regression model, we found that the probability of females being nonparous or parous at capture varied significantly with time, space and population density. The final model producing the best fit to data predicted that the proportion of nonparous females would be slightly larger over winter and substantially larger after high-density breeding seasons, which is consistent with the tested prediction. With increasing densities during the breeding seasons, both the nonparous and parous females became older at the onset of winter. Again, the field evidence was consistent with the predicted pattern. The age of parous... [ABSTRACT FROM AUTHOR]

1. Voles undergo pronounced oscillations over periods of 3–5 years in northern Europe. A latitudinal gradient of cycle periods and amplitudes has been reported for Fennoscandia, with periods and amplitudes increasing towards northern latitudes. 2. This study formulates a discrete time model based on maternal effects to explain the density fluctuation patterns of microtine rodents. The phenotypic transmission of quality from mothers to offspring generates delayed density dependence, which produces cyclic behaviour in the model. 3. The dynamic patterns predicted by the maternal effect model agree with data. We conclude that the maternal effect hypothesis is a plausible, parsimonious explanation for vole-density cycles in northern Europe. [ABSTRACT FROM AUTHOR]

Dreissenid mussels (including the zebra mussel Dreissena polymorpha and the quagga mussel D. rostriformis) are among the world's most notorious invasive species, with large and widespread ecological and economic effects. However, their long‐term population dynamics are poorly known, even though these dynamics are critical to determining impacts and effective management. We gathered and analyzed 67 long‐term (>10 yr) data sets on dreissenid populations from lakes and rivers across Europe and North America. We addressed five questions: (1) How do Dreissena populations change through time? (2) Specifically, do Dreissena populations decline substantially after an initial outbreak phase? (3) Do different measures of population performance (biomass or density of settled animals, veliger density, recruitment of young) follow the same patterns through time? (4) How do the numbers or biomass of zebra mussels or of both species combined change after the quagga mussel arrives? (5) How does body size change over time? We also considered whether current data on long‐term dynamics of Dreissena populations are adequate for science and management. Individual Dreissena populations showed a wide range of temporal dynamics, but we could detect only two general patterns that applied across many populations: (1) Populations of both species increased rapidly in the first 1–2 yr after appearance, and (2) quagga mussels appeared later than zebra mussels and usually quickly caused large declines in zebra mussel populations. We found little evidence that combined Dreissena populations declined over the long term. Different measures of population performance were not congruent; the temporal dynamics of one life stage or population attribute cannot generally be accurately inferred from the dynamics of another. We found no consistent patterns in the long‐term dynamics of body size. The long‐term dynamics of Dreissena populations probably are driven by the ecological characteristics (e.g., predation, nutrient inputs, water temperature) and their temporal changes at individual sites rather than following a generalized time course that applies across many sites. Existing long‐term data sets on dreissenid populations, although clearly valuable, are inadequate to meet research and management needs. Data sets could be improved by standardizing sampling designs and methods, routinely collecting more variables, and increasing support. [ABSTRACT FROM AUTHOR]

In this study, we describe the landscape of human demographic expansions in Eurasia using a large continental Y chromosome and mitochondrial DNA dataset. Variation at these two uniparentally-inherited genetic systems retraces expansions that occurred in the past 60 ky, and shows a clear decrease of expansion ages from east to west Eurasia. To investigate the demographic events at the origin of this westward decrease of expansion ages, the estimated divergence ages between Eurasian populations are compared with the estimated expansion ages within each population. Both markers suggest that the demographic expansion diffused from east to west in Eurasia in a demic way, i.e., through migrations of individuals (and not just through diffusion of new technologies), highlighting the prominent role of eastern regions within Eurasia during Palaeolithic times., ((c) 2008 Wiley-Liss, Inc.)

Ethiopia is central to population genetic studies investigating the out of Africa expansion of modern humans, as shown by Y chromosome and mtDNA studies. To address the level of genetic differentiation within Ethiopia, and its relationship to Sub-Saharan Africa and Eurasia, we studied an 8 kb segment of the X-chromosome from 72 chromosomes from the Amhara, Oromo and Ethiopian Jews, and compared these results with 804 chromosomes from Middle Eastern, African, Asian and European populations, and 22 newly typed Saharawi. Within Ethiopia the two largest ethnic groups, the Amhara and Oromo, were not found to be statistically distinct, based on an exact test of haplotype frequencies. The Ethiopian Jews appear as an admixed population, possibly of Jewish origin, though the data remain equivocal. There is evidence of a close relationship between Ethiopian and Yemenite Jews, likely a result of indirect gene flow. Within an African and Eurasian context, the distribution of alleles of a variable T(n) repeat, and the spread of haplotypes containing Africa-specific alleles, provide evidence of a genetic continuity from Sub-Saharan Africa to the Near East, and furthermore suggest that a bottleneck occurred in Ethiopia associated with an out of Africa expansion. Ethiopian genetic heterogeneity, as evidenced by principal component analysis of haplotype frequencies, most likely resulted from periods of subsequent admixture. While these results are from the analysis of one locus, we feel that in association with data from other marker systems they add a complementary perspective on the history of Ethiopia.

In a number of practical cases it is important to determine the likely geographical origin of an individual or a biological sample. A dead body, old bones or a sample of semen may be available. Information on where the sample might come from can assist investigation or research. The first part of this paper is independent of specific data structure. We formulate the problem as a classification problem. Bayes' theorem allows different sources of information or data to be reconciled conveniently. The main part of the paper involves high dimensional data for which simple, standard methods are not likely to work properly. Mitochondrial DNA (mtDNA) data is a typical example of such data. We propose a procedure involving essentially two steps. First, principal component analysis is used to reduce the dimension of the data. Next, quadratic discriminant analysis performs the actual classification. A cross validation procedure is implemented to select the optimal number of principal components. The importance of using separate data sets for model fitting and testing is emphasized. This method distinguishes well between individuals with a self reported European (Icelandic or German) origin and SE Africans. In this case the error rate is 2.0%.

Genetic variation at seven microsatellite DNA loci was quantified in 19 herds of wild caribou and domestic reindeer (Rangifer tarandus) from North America, Scandinavia and Russia. There is an average of 2.0-6.6 alleles per locus and observed individual heterozygosity of 0.33-0.50 in most herds. A herd on Svalbard Island, Scandinavia, is an exception, with relatively few alleles and low heterozygosity. The Central Arctic, Western Arctic and Porcupine River caribou herds in Alaska have similar allele frequencies and comprise one breeding population. Domestic reindeer in Alaska originated from transplants from Siberia, Russia, more than 100 years ago. Reindeer in Alaska and Siberia have different allele frequencies at several loci, but a relatively low level of genetic differentiation. Wild caribou and domestic reindeer in Alaska have significantly different allele frequencies at the seven loci, indicating that gene flow between reindeer and caribou in Alaska has been limited.

Previous genetic and craniometric studies have suggested greater genetic diversity and a larger effective size in Africa. Several demographic scenarios can explain a larger African effective size, and anthropological geneticists have attempted to obtain better estimates of relative population sizes among continental regions in the Old World. A least-squares approach of estimating relative population weights was developed by Relethford and Harpending ([1994] Am. J. Phys. Anthropol. 95:249-270), who applied it to craniometric and genetic data sets and concluded that the ratio of African, Asian, and European effective sizes was 3:1:1, respectively; another data set of short tandem repeat (STR) markers yielded a similar estimate of 7:1:2. However, an estimate from restriction site polymorphism (RSP, also known as restriction fragment length polymorphism, or RFLP) data yielded a very different estimate of 1:1:8. Thus, the European and not the African effective size was largest. Simulations showed that this was the result of ascertainment bias in which polymorphic markers were originally identified in a small panel of Caucasians, leading to inflated heterozygosity in the European sample and thus an inflated population weight. This paper extends those computer simulations to incorporate not only ascertainment bias but also interpopulation gene flow and demographic expansion in two types of genetic data, single nucleotide polymorphisms (SNPs, which are similar but not precisely identical to RSPs) and STRs. The effects of these three parameters on SNP and STR relative weight estimates are described. Simulations show that the ascertainment scheme affects SNP data but not STR data. Gene flow has a noticeable effect on the bias and efficiency of the estimates in both types of genetic data. Population expansions have a large effect only in one ascertainment scheme in the simulated SNP data and no effect in STR data. Relative population weight estimates from four published STR data sets are also reported. These estimates are similar to each other: all show a larger African weight and a European weight somewhat larger than the Asian weight. Because the STR simulations show that when gene flow is greater than 0.01 migrants per generation the African population weight is biased upward, it is likely that the African weights in the four STR data sets are inflated. However, the simulations suggest that the African effective size is still largest of the three regions and is probably at least as great as the sum of the Asian and European effective sizes., (Copyright 2001 Wiley-Liss, Inc.)

We analyzed admixture in samples of six different African-American populations from South Carolina: Gullah-speaking Sea Islanders in coastal South Carolina, residents of four counties in the "Low Country" (Berkeley, Charleston, Colleton, and Dorchester), and persons living in the city of Columbia, located in central South Carolina. We used a battery of highly informative autosomal, mtDNA, and Y-chromosome markers. Two of the autosomal markers (FY and AT3) are linked and lie 22 cM apart on chromosome 1. The results of this study indicate, in accordance with previous historical, cultural, and anthropological evidence, a very low level of European admixture in the Gullah Sea Islanders (m = 3.5 +/- 0.9%). The proportion of European admixture is higher in the Low Country (m ranging between 9. 9 +/- 1.8% and 14.0 +/- 1.9%), and is highest in Columbia (m = 17.7 +/- 3.1%). A sex-biased European gene flow and a small Native American contribution to the African-American gene pool are also evident in these data. We studied the pattern of pairwise allelic associations between the FY locus and the nine other autosomal markers in our samples. In the combined sample from the Low Country (N = 548), a high level of linkage disequilibrium was observed between the linked markers, FY and AT3. Additionally, significant associations were also detected between FY and 4 of the 8 unlinked markers, suggesting the existence of significant genetic structure in this population. A continuous gene flow model of admixture could explain the observed pattern of genetic structure. A test conditioning on the overall admixture of each individual showed association of ancestry between the two linked markers (FY and AT3), but not between any of the unlinked markers, as theory predicts. Thus, even in the presence of genetic structure due to continuous gene flow or some other factor, it is possible to differentiate associations due to linkage from spurious associations due to genetic structure., (Copyright 2001 Wiley-Liss, Inc.)

The hypervariable segment I of the control region of the mtDNA (positions 16024-16383) was PCR-amplified from mouth scrape and hairs and sequenced in 45 unrelated individuals of pure matrilineal Basque descent. Twenty-seven different sequences were found, of which 21 are unique to the Basques. The allelic partition observed, together with resampling experiments, suggested that much more variation remained to be discovered. The mean pairwise difference in number of nucleotides between individuals was 3-15, a very low value. Moreover, the number of steps for the most parsimonious tree is very low compared to the number of different sequences. Both findings suggest that the Basque population was founded by a few lineages that diverged in a short time span. The number of nucleotide differences between individuals was shown not to be influenced by the distance between their birthplaces, thus validating the sampling strategy used a posteriori. The pairwise difference distribution agreed well with the three-parameter model proposed by Rogers & Harpending (1992). The parameter estimates found for the Basques implied that a demographic expansion (or perhaps two, given the bimodal shape of the distribution) took place sometime between 14500 and 42000 BP which is in agreement with archaeological data. Our sample was compared to other populations for which D-loop sequences were available through the Nei & Miller (1990) distance. In a neighbour-joining tree, all the Caucasoid samples, including the Basques, appeared tightly clustered, whereas African samples were the most distant to the Caucasoids and also the most heterogeneous. Although classical markers, such as blood groups and protein polymorphisms, clearly separate the Basques (and the Sardinians) from other European populations, this distinctiveness was not found using D-loop sequences.

The hypothesis that both genetic and linguistic similarities among Eurasian and North African populations are due to demic diffusion of neolithic farmers is tested against a wide database of allele frequencies. Demic diffusion of farming and languages from the Near East should have determined clines in areas defined by linguistic criteria; the alternative hypothesis of cultural transmission does not predict clines. Spatial autocorrelation analysis shows significant gradients in three of the four linguistic families supposedly affected by neolithic demic diffusion; the Afroasiatic family is the exception. Many such gradients are not observed when populations are jointly analyzed, regardless of linguistic classification. This is incompatible with the hypothesis that major cultural transformations in Eurasia (diffusion of related languages and spread of agriculture) took place without major demographic changes. The model of demic diffusion seems therefore to provide a mechanism explaining coevolution of linguistic and biological traits in much of the Old World. Archaeological, linguistic, and genetic evidence agree in suggesting a multidirectional process of gene flow from the Near East in the neolithic. However, the possibility should be envisaged that some allele frequency patterns can predate the neolithic and depend on the initial spread of Homo sapiens sapiens from Africa into Eurasia.