Population dynamics of the Corncrake Crex crex in Slovenia in the 1992–2021 period

Habitat selection of the Eurasian Scops Owl Otus scops was studied in Ljubljansko barje (central Slovenia, 180 km2) where abiotic conditions, especially climate, could be considered suboptimal for this xerothermophilic species. Data on the number and distribution of calling males were gathered in May and June 2004–06 using the playback method. A total of 137 calling males were counted (29 in 2004, 66 in 2005, 42 in 2006). To avoid pseudo-replication, 72 non-overlapping sites were selected for habitat analysis. Habitat within 250-m radius plots surrounding owl sites was compared with 136 unoccupied and non-overlapping sites. Within plots, 14 habitat variables were measured. Discriminating variables between occupied and non-occupied sites were identified with stepwise logistic regression. Scops Owl occupation was positively associated with the number of tree lines, and slightly negative with the surface area of woodland and settlements. Scops Owls preferred sites with a higher than average proportion of traditional orchards, tree lines, scrub, unimproved meadows, and tree plantations. Tree plantations were only used by owls during 2005, when the number of calling males was highest. All males were unpaired, perhaps indicating inexperienced or late-arriving males outcompeted to marginal habitat. Conservation actions needed to maintain this population of Scops Owl at the northern border of its breeding range include: (1) preserve and rejuvenate traditional orchards and isolated trees in farmyards, (2) encourage renovation of old houses and their farmyards and discourage high density housing, (3) protect and restore tree lines and copses, (4) enlarge the proportion of unimproved meadows, and (5) limit the increase of cropland and the use of biocides.

The ecological niche is the conceptual foundation for the analysis of species distributions. Habitat variables and resources are therefore thought to determine the distribution of a species. However, metapopulation and source-sink models posit that population processes determine the local distribution of a species; metapopulation theory suggests that many suitable patches could be unoccupied and source-sink theory suggests that unsuitable patches could be occupied. We examined whether the distribution of 2 European anurans (tree frog [Hyla arborea] and natterjack toad [Bufo calamita]) was determined by habitat variables, local population size (as indexed by the number of calling males), or metapopulation characteristics are. We found that the distribution of both species was best predicted by the number of calling males in the previous years. This supports the idea that population processes are more important determinants of distribution than habitat characteristics. We suggest that future distribution models explicitly incorporate population dynamic processes. Our results suggest that there is a threshold number of calling males above which a population is almost certain to persist in the short-term. If more robust population data are not available, such a threshold should be useful for managing threatened anuran species because the number of calling males is easily determined.

An estimation of the scope for BCG vaccination in preventing tuberculosis among those aged 15–19 years in England and Wales at the present time

The Australian lungfish, Neoceratodus forsteri, is one of the world’s oldest vertebrate lineages, with a slow life-history and threatened status, requiring immediate conservation efforts. The main threats to lungfish populations are degradation and availability of key macrophyte habitats, water regulation and flow modification. As this long-lived species (at least 77 years) has delayed maturity (mature at 10 years), field monitoring alone will not be enough to inform the challenge of ensuring sustainable populations. A stochastic metapopulation model was developed for the Burnett River (Southeast Queensland, Australia), an important habitat for the lungfish that is a highly regulated system with extensive water infrastructure. The model consists of three interacting populations, where the ecology and biology of the species were translated into an 80-year-class population projection matrix for each population, each with post-development streamflow, habitat and movement rules. The model highlights the longer-term interaction between dams and stream flows on habitat availability and subsequent recruitment. Through a pre-development streamflow, we quantify the impact of high regulation and development on the lungfish population in the Burnett River: a minor decline in the upstream population (e.g., 9.8% decline), a large decline in the middle population (64.2% decline), virtually no change in the downstream population (e.g., 1.2% decline) and a moderate decline in the overall metapopulation (e.g., 22.3% decline). The loss of spawning and feeding habitat remains the main reason for population decline, with implications that the loss will lead to greater pressure on remaining downstream habitat due to combined flow and dam effects and, in turn, to extended periods of recovery of spawning habitat. Our modeling approach substantially advances conservation management of this species, as it can be adapted to suit other populations in other river systems and used to test sensitivity to recovery actions.

Whole vine (K(plant)) and individual root (K(root)) hydraulic conductances were measured in kiwifruit (Actinidia chinensis Planch. var. chinensis 'Hort16A') vines to observe hydraulic responses following partial root system excision. Heat dissipation and compensation heat pulse techniques were used to measure sap flow in trunks and individual roots, respectively. Sap flux and measurements of xylem pressure potential (Ψ) were used to calculate K(plant) and K(root) in vines with zero and ∼80% of roots severed. Whole vine transpiration (E), Ψ and K(plant) were significantly reduced within 24 h of root pruning, and did not recover within 6 weeks. Sap flux in intact roots increased within 24 h of root pruning, driven by an increase in the pressure gradient between the soil and canopy and without any change in root hydraulic conductance. Photosynthesis (A) and stomatal conductance (g(s)) were reduced, without significant effects on leaf internal CO(2) concentration (c(i)). Shoot growth rates were maintained; fruit growth and dry matter content were increased following pruning. The woody roots of kiwifruit did not demonstrate a rapid dynamic response to root system damage as has been observed previously in monocot seedlings. Increased sap flux in intact roots with no change in K(root) and only a moderate decline in shoot A suggests that under normal growing conditions root hydraulic conductance greatly exceeds requirements for adequate shoot hydration.

SummaryBackgroundLarge-scale and contemporary population-based studies of heart failure incidence are needed to inform resource planning and research prioritisation but current evidence is scarce. We aimed to assess temporal trends in incidence and prevalence of heart failure in a large general population cohort from the UK, between 2002 and 2014.MethodsFor this population-based study, we used linked primary and secondary electronic health records of 4 million individuals from the Clinical Practice Research Datalink (CPRD), a cohort that is representative of the UK population in terms of age and sex. Eligible patients were aged 16 years and older, had contributed data between Jan 1, 2002, and Dec 31, 2014, had an acceptable record according to CPRD quality control, were approved for CPRD and Hospital Episodes Statistics linkage, and were registered with their general practice for at least 12 months. For patients with incident heart failure, we extracted the most recent measurement of baseline characteristics (within 2 years of diagnosis) from electronic health records, as well as information about comorbidities, socioeconomic status, ethnicity, and region. We calculated standardised rates by applying direct age and sex standardisation to the 2013 European Standard Population, and we inferred crude rates by applying year-specific, age-specific, and sex-specific incidence to UK census mid-year population estimates. We assumed no heart failure for patients aged 15 years or younger and report total incidence and prevalence for all ages (>0 years).FindingsFrom 2002 to 2014, heart failure incidence (standardised by age and sex) decreased, similarly for men and women, by 7% (from 358 to 332 per 100 000 person-years; adjusted incidence ratio 0·93, 95% CI 0·91–0·94). However, the estimated absolute number of individuals with newly diagnosed heart failure in the UK increased by 12% (from 170 727 in 2002 to 190 798 in 2014), largely due to an increase in population size and age. The estimated absolute number of prevalent heart failure cases in the UK increased even more, by 23% (from 750 127 to 920 616). Over the study period, patient age and multi-morbidity at first presentation of heart failure increased (mean age 76·5 years [SD 12·0] to 77·0 years [12·9], adjusted difference 0·79 years, 95% CI 0·37–1·20; mean number of comorbidities 3·4 [SD 1·9] vs 5·4 [2·5]; adjusted difference 2·0, 95% CI 1·9–2·1). Socioeconomically deprived individuals were more likely to develop heart failure than were affluent individuals (incidence rate ratio 1·61, 95% CI 1·58–1·64), and did so earlier in life than those from the most affluent group (adjusted difference −3·51 years, 95% CI −3·77 to −3·25). From 2002 to 2014, the socioeconomic gradient in age at first presentation with heart failure widened. Socioeconomically deprived individuals also had more comorbidities, despite their younger age.InterpretationDespite a moderate decline in standardised incidence of heart failure, the burden of heart failure in the UK is increasing, and is now similar to the four most common causes of cancer combined. The observed socioeconomic disparities in disease incidence and age at onset within the same nation point to a potentially preventable nature of heart failure that still needs to be tackled.FundingBritish Heart Foundation and National Institute for Health Research.

Breeding bird surveys were initiated on George Washington Carver National Monument, Missouri, in 2008 to assess temporal changes in the species composition and abundance of birds on the park and to improve our understanding of relationships between breeding birds and their habitat and the effects of management actions, such as invasive plant species control and tree thinning, on bird populations. Birds were sampled using point counts with 70 variable circular plots located on a systematic grid of 100 x 100-m cells (originating from a random start point). All birds seen or heard on a plot during a 5-min sampling period were recorded. In the 13 years since initiating our breeding bird surveys on the park, birds were surveyed on as many of the 70 variable circular plots as possible each year, resulting in 520 cumulative plot visits. Surveys have yielded records for 100 different species of birds. Ninety-seven of the species recorded are classified as permanent or summer residents to the area, two are classified as transients in the area, and one as a winter resident to the area. Six breeding species recorded are considered species of conservation concern for the Central Hardwoods Bird Conservation Region, the bird conservation region in which George Washington Carver National Monument is located. Of the 97 breeding species recorded, ten species in grassland habitat and six in woodland habitat occurred in numbers large enough to calculate annual abundances with some degree of confidence. Trends in abundance were classified as uncertain for most species, which means that there were no significant increases or decreases, but it is not certain that trends were < 5% per year. The Northern Cardinal (Cardinalis cardinalis) in woodland habitat was stable. The Eastern Meadowlark (Sturnella magna) in grassland habitat was in moderate decline, and the Northern Bobwhite (Colinus virginianus) in grassland habitat was in steep decline. Comparing population trends (i.e., changes in population size over time) on the park with regional trends for the Central Hardwoods Bird Conservation Region suggests that the bird community at George Washington Carver National Monument is faring similarly to that of the region as a whole. Trends in the park’s popula-tions of Field Sparrow (Spizella pusilla) and Indigo Bunting (Passerina cyanea) in grassland habitat and Carolina Wren (Thryothorus ludovicianus) in woodland habitat were uncertain, whereas they declined significantly in the larger region, which could be a result of management on George Washington Carver National Monument. Red-bellied Woodpecker (Melanerpes carolinus) population trends, while uncertain in grassland habitat on the park, increased significantly in the region. The Red-bellied Woodpecker utilizes trees for foraging, which are sparse in the grassland habitat on the park. Declining diversity and richness values suggest that park habitat is declining in its ability to meet the requirements of many of the park’s breeding bird species. This decline in species richness could reflect habitat management practices, but it could also reflect the influences of larger-scale factors such as weather or climatic conditions on vegetation. Therefore, continued monitoring of birds and their habitats on George Washington Carver National Monument as management and weather and climatic conditions change is essential for park management.

Trends in smoking and lung cancer mortality in Switzerland

Biodiversity is severely threatened by habitat destruction. As a consequence of habitat destruction, the remaining habitat becomes more fragmented. This results in time-lagged population extirpations in remaining fragments when these are too small to support populations in the long term. If these time-lagged effects are ignored, the long-term impacts of habitat loss and fragmentation will be underestimated. We quantified the magnitude of time-lagged effects of habitat fragmentation for 157 nonvolant terrestrial mammal species in Madagascar, one of the biodiversity hotspots with the highest rates of habitat loss and fragmentation. We refined species' geographic ranges based on habitat preferences and elevation limits and then estimated which habitat fragments were too small to support a population for at least 100 years given stochastic population fluctuations. We also evaluated whether time-lagged effects would change the threat status of species according to the International Union for the Conservation of Nature (IUCN) Red List assessment framework. We used allometric relationships to obtain the population parameters required to simulate the population dynamics of each species, and we quantified the consequences of uncertainty in these parameter estimates by repeating the analyses with a range of plausible parameter values. Based on the median outcomes, we found that for 34 species (22% of the 157 species) at least 10% of their current habitat contained unviable populations. Eight species (5%) had a higher threat status when accounting for time-lagged effects. Based on 0.95-quantile values, following a precautionary principle, for 108 species (69%) at least 10% of their habitat contained unviable populations, and 51 species (32%) had a higher threat status. Our results highlight the need to preserve continuous habitat and improve connectivity between habitat fragments. Moreover, our findings may help to identify species for which time-lagged effects are most severe and which may thus benefit the most from conservation actions.

Amphibian populations fluctuate naturally in size and range and large datasets are required to establish trends in species dynamics. To determine population trends for the endangered Suweon Treefrog (Dryophytes suweonensis), we conducted aural surveys in 2015, 2016, and 2017 at each of 122 sites where the species was known to occur in the Republic of Korea. Despite being based on individual counts, the focus of this study was to establish population trends rather than population size estimates, and we found both environmental and landscape variables to be significant factors. Encroachment was also a key factor that influenced both the decreasing number of calling individuals and the negative population dynamics, represented here by the difference in the number of calling individuals between years. Generally, most sites displayed minimal differences in the number of calling males between years, although there was a large fluctuation in the number of individuals at some sites. Finally, when adjusted for the overall population size difference between years, we found the population size to be decreasing between 2015 and 2017, with a significant decrease in the number of calling individuals at specific sites. High rate of encroachment was the principal explanatory factor behind these marked negative peaks in population dynamics.

Ecological conditions are likely to change with increasing urbanization, influencing the demography and size of animal populations. Although one of the most tightly linked species to humans, the house sparrow has been suffering a significant decline worldwide, especially in European cities. Several factors have been proposed to explain this conspicuous loss of urban sparrows, but studies evaluating these factors are usually restricted to Britain where the decline was very drastic, and it is unclear whether similar or different processes are affecting urban populations of the species elsewhere. In this study we investigated the reproductive success of urban and rural sparrows in a central European country, Hungary where our census data indicate a moderate decline during the last decade. We found that rural pairs produced more and larger fledglings than suburban pairs, and the difference remained consistent in two years with very contrasting meteorological conditions during breeding. This difference is likely explained by habitat differences in nestling diet, because we found that 1) rural parents provided large prey items more often than suburban parents, 2) birds from differently urbanized habitats produced fledglings of similar number and size in captivity under identical rearing conditions with ample food for nestlings, and 3) in a cross‐fostering experiment, nestlings tended to grow larger in rural than in suburban nests irrespective of their hatching environment. These results agree with those found in a recent British study, indicating that poor nestling development and survival due to inadequate diet may be widespread phenomena in urbanized habitats.

BackgroundSteppe-birds face drastic population declines throughout Europe. The Dupont’s lark Chersophilus duponti is an endangered steppe-bird species whose European distribution is restricted to Spain. This scarce passerine bird could be considered an ‘umbrella species’, since its population trends may reveal the conservation status of shrub-steppes. However, trends for the Spanish, and thus European, population of Dupont’s lark are unknown. In this work, we evaluated Dupont’s lark population trends in Europe employing the most recent and largest compiled database to date (92 populations over 12 years). In addition, we assessed the species threat category according to current applicable criteria (approved in March 2017) in the Spanish catalogue of threatened species (SCTS), which have never been applied to the Dupont’s lark nor to any other Spanish species. Finally, we compared the resulting threat categories with the current conservation status at European, national and regional levels.MethodsWe fitted switching linear trend models (software TRIM—Trends and Indices for Monitoring data) to evaluate population trends at national and regional scale (i.e. per Autonomous Community) during the period 2004–2015. In addition, the average finite annual rate of change (n}{}overline lambda ) obtained from the TRIM analysis was employed to estimate the percentage of population size change in a 10-year period. A threat category was assigned following A1 and A2 criteria applicable in the SCTS.ResultsTrends showed an overall 3.9% annual decline rate for the Spanish population (moderate decline, following TRIM). Regional analyses showed high inter-regional variability. We forecasted a 32.8% average decline over the next 10 years. According to these results, the species should be listed as ‘Vulnerable’ at a national scale (SCTS). At the regional level, the conservation status of the species is of particular concern in Andalusia and Castile-Leon, where the species qualifies for listing as ‘Endangered’.DiscussionOur results highlight the concerning conservation status of the European Dupont’s lark population, undergoing a 3.9% annual decline rate. Under this scenario, the implementation of a wide-ranging conservation plan is urgently needed and is vital to ensuring the conservation of this steppe-bird species. The role of administrations in matters of nature protection and the cataloguing of endangered species is crucial to reverse declining population trends of this and other endangered taxa.

National Jewish population surveys in the United States provide comprehensive data and insights about the Jewish community’s development. Controversy accompanied the 2000–2001 National Jewish Population Survey (NJPS) since inception and through release of the final report. This paper focuses on the plausibility of Jewish population size—namely, a decline since 1990—as estimated from the 2001 NJPS. While the size of the U.S. Jewish population is difficult to ascertain, growth momentum reached its peak around 1990, followed by moderate decline. Population aging and a decline in the wish to identify as a Jew underlie a decrease in the Jewish population. In retrospect, the 1957 Current Population Survey and 1990 NJPS probably better represented the total Jewish population, while the 1970 NJPS and 2001 NJPS better covered the more Jewishly identified sections. NJPS 2001, in any case, is an important and usable source.

Quantifying the effects of landscape change on population connectivity is compounded by uncertainties about population size and distribution and a limited understanding of dispersal ability for most species. In addition, the effects of anthropogenic landscape change and sensitivity to regional climatic conditions interact to strongly affect habitat fragmentation and loss. To further develop conservation theory and to understand the interplay between all of these factors, we simulated habitat fragmentation and loss across the Western United States for several hypothetical species associated with four biome types, and a range of habitat requirements and dispersal abilities. We found dispersal ability and population size of the focal species to be equally sensitive to habitat extent, while dispersal ability is more sensitive to habitat fragmentation. There were also strong critical threshold effects where habitat connectivity decreased disproportionately to decreases in life-history traits making these species near these thresholds more sensitive to changes in habitat loss and fragmentation. Overall, grassland and forest associated species are also most at risk from habitat loss and fragmentation driven by human related land-use. These two largest biome types were most sensitive at large contiguous patch sizes which is often considered most important for metapopulation viability and biodiversity conservation. Hypothetical simulation studies such as this can be of great value to scientists in further conceptualizing and developing conservation theory, and evaluating spatially-explicit scenarios of habitat connectivity. Our results are available for download in a web-based interactive mapping prototype useful for accessing the results of this study.

Anthropogenic habitat fragmentation has well-established deleterious effects on populations and communities of native vertebrates, but the mechanisms underlying population decline under fragmentation remain poorly understood. Most studies of vertebrates in anthropogenically-fragmented habitats have focused on population density, demographics or fecundity. Relatively little attention has been given to indices of health status, body condition or physiological stress. In this study, 30 populations of a small marsupial, the agile antechinus (Antechinus agilis), living in anthropogenically-fragmented forest patches were sampled in two years (2007 and 2008). Immediately after sampling in each fragment, a population in a matched control site in similar, but unfragmented forest (a 'pseudofragment') was sampled. Indices of population density (relative abundance), estimated fat reserves (mass-size residuals), health status (erythrocyte variables), parasite load (simplified ectoparasite counts and eosinophil percentages) and chronic physiological stress (total and differential immune cell counts) were examined. Relative abundances were lower and parasite load indices higher in fragmented than continuous forest. Fragment populations displayed indications of regenerative anaemia, which is related to poor health status and potentially caused by chronic stress, frequent blood loss or heavy parasite loads. Estimated fat reserves were higher in fragment than continuous forest populations. Nonetheless, differential leukocyte counts suggested that chronic physiological stress was greater (i.e. greater neutrophil-to-lymphocyte ratios) (N:L) in populations in fragments. Anthropogenic fragmentation effects are not often distinguished in the ecological literature from those of co-occurring processes, such as habitat loss and degradation. To investigate the effects of these processes, environmental factors were examined that were thought to have a potential influence on agile antechinus (e.g. fragment patch core area, proportion of edge habitat, isolation, woody debris abundance, shrub density etc). Relative abundance of agile antechinus was positively correlated with forest patch core area and native tree-cover within a 0.5 km radius of a study site. Estimated fat reserves, particularly in males, were greater in populations in fragments with a smaller core area, but statistical modelling indicated that the effect was an indirect one: males had greater estimated fat reserves where the abundance of conspecifics was lower, suggesting that this metric was responding to intraspecific competition and per capita food availability. Health status, indexed by erythrocyte indicators of regenerative anaemia,was positively associated with greater microhabitat heterogeneity, and abundance of shrubs, logs and native trees other than Eucalyptus species. Female abundances were lower in edge habitat (< 60 m from edge) than in fragment interiors (> 80 m from edge), and females had higher chronic stress indicators (N:L) where fragments were more highly dissected by edge habitat. Although parasite load indices and male N:L were higher in fragment than continuous forest sites, the environmental factors responsible were not identified. The study has demonstrated that anthropogenic habitat fragmentation, loss and degradation can have broadly negative effects on a native vertebrate, not only on its population density, but also in terms of health status and chronic physiological stress. This is a serious concern from a conservation management perspective, because chronic stress has pronounced fitness-reducing effects in vertebrates, including reduced reproductive investment, fecundity and survivorship.