Dermacentor reticulatus – a tick on its way from glacial refugia to a panmictic Eurasian population

The ornate dog tick (Dermacentor reticulatus) shows a recently expanding geographic distribution. Knowledge on its intraspecific variability, population structure, rate of genetic diversity and divergence, including its evolution and geographic distribution, is crucial to understand its dispersal capacity. All such information would help to evaluate the potential risk of future spread of associated pathogens of medical and veterinary concern. A set of 865 D. reticulatus ticks was collected from 65 localities across 21 countries, from Portugal in the west to Kazakhstan and southern Russia in the east. Cluster analyses of 16 microsatellite loci were combined with nuclear (ITS2, 18S) and mitochondrial (12S, 16S, COI) sequence data to uncover the ticks’ population structures and geographical patterns. Approximate Bayesian computation was applied to model evolutionary relationships among the found clusters. Low variability and a weak phylogenetic signal showing an east–west cline were detected both for mitochondrial and nuclear sequence markers. Microsatellite analyses revealed three genetic clusters, where the eastern and western cluster gradient was supplemented by a third, northern cluster. Alternative scenarios could explain such a tripartite population structure by independent formation of clusters in separate refugia, limited gene flow connected with isolation by distance causing a “bipolar pattern”, and the northern cluster deriving from admixture between the eastern and western populations. The best supported demographic scenario of this tick species indicates that the northern cluster derived from admixture between the eastern and western populations 441 (median) to 224 (mode) generations ago, suggesting a possible link with the end of the Little Ice Age in Europe.     

How predacious are predators? A study on Ocypus similis,a rove beetle of cereal fields

It is attempted determine the diet breadth and to quantify the predator pressure by Ocypus similis (F.) (Coleoptera: Staphylinidae), a dominant species of the rove beetle fauna in a winter wheat field. Laboratory and field experiments were conducted to determine the range of prey taxa and the consumption of a whole predator generation (including larvae) during its activity in the field. In laboratory experiments, adults and larvae of O. similis fed on a variety of prey except spiders and larvae of soldier beetles (Cantharidae), but they preferred millipedes as food (Diplopoda: Julidae, Polydesmidae). This preference could also be observed in the field. Although the predator population reached its maximum density in April, highest predator pressure occurred in June because of high consumption rates during the second larval stage. Adult beetles and the individuals of the second larval stage contributed both about 1/3 to total population consumption. Predation by adult beetles was mainly restricted to early spring and summer while larval consumption was highest from April to July. The staphylinids reduced the population density of diplopods by 7–35%. Because millipedes are an important part of the decomposer community, predator activity may lead to a decrease of decomposition rates.     

How important are trophic state,macrophyte and fish population effects on cladoceran community? A study in Lake Erhai

Environmental controls on cladoceran community structure in lake ecosystems are complex and may involve many environmental parameters including trophic state and fish populations. In Lake Erhai, a plateau lake located in southwest China, it was hypothesized that a combination of lake eutrophication and planktivorous fish introduction would increase the abundance of cladoceran, while also decreasing cladoceran size. To test this hypothesis, we examined temporal changes in cladoceran microfossils in the sediments of Lake Erhai over the past century. The influence of changing macrophyte coverage within the littoral region of the lake was also considered. Results demonstrated that cladoceran abundance (measured as flux of cladoceran fossils in the sediments) increased markedly accompanying eutrophication of the lake. In addition, there was a shift in the dominant cladoceran species from those species that prefer oligotrophic conditions to those that prefer mesotrophic and eutrophic conditions. A reduction in the ephippium length of Daphnia spp. was observed and attributed to the introduction of the planktivorous fish Neosalanx taihuensis. Our findings indicated that eutrophication and fish introduction were the main controls affecting cladoceran community structure during the recent decades, and predation by planktivorous fish had an important impact on Daphnia body size.     

How threatened are alpine environments? a cross taxonomic study

Cold-adapted ecosystems are often considered to be stable, species poor, and well protected. However, such ecosystems have been identified as being especially sensitive to threats from global warming. Despite this, recent studies have found low proportions of Red Listed species in these systems. In this study we explored the number of alpine species (dependent on alpine habitats for their survival) and their Red List status in Sweden. We determined the proportion of Red Listed species and explored discrepancies among different groups of organisms in terms of the proportion of Red Listed species and the criteria used for Red Listing. We found a total of 389 alpine species in twelve analyzed species groups. The overall proportion of Red Listed species was 29%, with 15% regarded as threatened. There were substantial differences among taxonomic groups with respect to the proportion of Red Listed species. Among mammals 75% of the species are Red Listed, along with 63% of butterflies and 50% of birds. In addition the single alpine dragonfly species and all three alpine stinging wasp species are also Red Listed. Although beetles, bumblebees and grasshoppers are represented by a total of 17 alpine species, none are Red Listed. In contrast to previous studies, our results show that the proportion of Red Listed species is high in alpine environments, indicating that ecosystems found above the tree line are indeed threatened. No species in Sweden have been Red Listed on the basis of the IUCN criterion E (unfavorable quantitative analysis), this is surprising since entire cold-adapted ecosystems are likely to disappear in the future. We highlight the need for a better and more coordinated application of the IUCN criteria, as well as a more stringent strategy to assess the extinction risks for alpine species, thus maintaining reliable Red Lists.     

How accurate are population models? Lessons from landscape‐scale tests in a fragmented system

There is a growing debate about the ability of Population Viability Analysis (PVA) to predict the risk of extinction. Previously, the debate has focused largely on models where spatial variation and species movement are ignored. We present a synthesis of the key results for an array of different species for which detailed tests of the accuracy of PVA models were completed. These models included spatial variation in habitat quality and the movement of individuals across a landscape. The models were good approximations for some species, but poor for others. Predictive ability was limited by complex processes typically overlooked in spatial population models, these being interactions between landscape structure and life history attributes. Accuracy of models could not be determined a priori, although model tests indicated how they might be improved. Importantly, model predictions were poor for some species that are among the best‐studied vertebrates in Australia. This indicated that although the availability of good life history data is a key part of PVA other factors also influence model accuracy. We were also able to draw broad conclusions about the sorts of populations and life history characteristics where model predictions are likely to be less accurate. Predictions of extinction risk are often essential for real‐world population management. Therefore, we believe that although PVA has been shown to be less than perfect, it remains a useful tool particularly in the absence of alternative approaches. Hence, tests of PVA models should be motivated by the cycle of testing and improvement.     

Effect of guanabenz on the peristaltic reflex and on the spontaneous rhythmic movements of the ileum isolated from the rabbit: do the alpha-2-adrenoreceptors constitute a homogenous population?

The inhibitory effect of the predominantly alpha-2 adrenoceptor agonist, guanabenz, on the peristaltic reflex and on the pendular movements of the rabbit isolated ileum was investigated. Guanabenz depressed or abolished the peristaltic reflex as well as the pendular movements. These effects were concentration-dependent. Guanabenz is much more potent inhibiting the peristaltic reflex (IC50 1 X 10(-7) M) than the pendular movements (IC50 1 X 10(-5) M). The choline ester, acetylcholine restored the peristaltic reflex and the anticholinesterase, eserine, restored the pendular movements previously abolished by guanabenz. During the blockade of the peristaltic reflex produced by guanabenz, the pendular movements were virtually not changed. It is therefore reasonable to suppose that the inhibitory effect of guanabenz reflects the different properties of alpha-2 adrenoceptors associated with cholinergic nerve terminals within the myenteric plexus and the longitudinal smooth muscle subserving the peristaltic reflex and the pendular movements.     

How many species of Hipposideros have occurred on Madagascar since the Late Pleistocene?

Populations of the Malagasy Hipposideros commersoni (family Hipposideridae) are threatened by deforestation and hunting. Maximum likelihood and Bayesian analysis of 148 cytochrome b sequences found this species to be paraphyletic and composed of three well‐supported monophyletic clades. Clades B and C form a monophyletic lineage that can be referred to H. commersoni; these two clades are separated by 6% sequence variation. Clade A represents a distinct evolutionary lineage separate (9–11% average sequence divergence) from H. commersoni (clades B and C) and is named herein as a new species, H ipposideros cryptovalorona sp. nov. In the phylogeny presented herein, this species is strongly associated with the outgroup taxa Hipposideros gigas and Hipposideros vittatus, both restricted to Africa. External, cranial and dental measurements taken from the same individuals used in the molecular study indicate no clear distinction in morphology amongst these three clades; this includes noseleaf structure and craniodental characteristics. Principal component analyses showed limited separation of the three clades. Comparison to a Quaternary fossil species from north‐west Madagascar, Hipposideros besaoka, found little morphological overlap between any of the three clades and this extinct species. Hence, at least three species of Hipposideros have occurred on Madagascar since the Late Pleistocene, two extant (H. commersoni s.s. and H. cryptovalorona sp. nov.) and one extinct (H. besaoka). © 2015 The Linnean Society of London     

How to lift a model for individual behaviour to the population level?

The quick answer to the title question is: by bookkeeping; introduce as p(opulation)-state a measure telling how the individuals are distributed over their common i(ndividual)-state space, and track how the various i-processes change this measure. Unfortunately, this answer leads to a mathematical theory that is technically complicated as well as immature. Alternatively, one may describe a population in terms of the history of the population birth rate together with the history of any environmental variables affecting i-state changes, reproduction and survival. Thus, a population model leads to delay equations. This delay formulation corresponds to a restriction of the p-dynamics to a forward invariant attracting set, so that no information is lost that is relevant for long-term dynamics. For such equations there exists a well-developed theory. In particular, numerical bifurcation tools work essentially the same as for ordinary differential equations. However, the available tools still need considerable adaptation before they can be practically applied to the dynamic energy budget (DEB) model. For the time being we recommend simplifying the i-dynamics before embarking on a systematic mathematical exploration of the associated p-behaviour. The long-term aim is to extend the tools, with the DEB model as a relevant goal post.     

How close are we to a predictive science of the biosphere?

In just 20 years, the field of biosphere-atmosphere interactions has gone from a nascent discipline to a central area of modern climate change research. The development of terrestrial biosphere models that predict the responses of ecosystems to climate and increasing CO2 levels has highlighted several mechanisms by which changes in ecosystem composition and function might alter regional and global climate. However, results from empirical studies suggest that ecosystem responses can differ markedly from the predictions of terrestrial biosphere models. As I discuss here, the challenge now is to connect terrestrial biosphere models to empirical ecosystem measurements. Only by systematically evaluating the predictions of terrestrial biosphere models against suites of ecosystem observations and experiments measurements will a true predictive science of the biosphere be achieved.     

How hazardous is the Sahara Desert crossing for migratory birds? Indications from satellite tracking of raptors

We investigated the risk associated with crossing the Sahara Desert for migrating birds by evaluating more than 90 journeys across this desert by four species of raptors (osprey Pandion haliaetus, honey buzzard Pernis apivorus, marsh harrier Circus aeruginosus and Eurasian hobby Falco subbuteo) recorded by satellite telemetry. Forty per cent of the crossings included events of aberrant behaviours, such as abrupt course changes, slow travel speeds, interruptions, aborted crossings followed by retreats from the desert and failed crossings due to death, indicating difficulties for the migrants. The mortality during the Sahara crossing was 31 per cent per crossing attempt for juveniles (first autumn migration), compared with only 2 per cent for adults (autumn and spring combined). Mortality associated with the Sahara passage made up a substantial fraction (up to about half for juveniles) of the total annual mortality, demonstrating that this passage has a profound influence on survival and fitness of migrants. Aberrant behaviours resulted in late arrival at the breeding grounds and an increased probability of breeding failure (carry-over effects). This study also demonstrates that satellite tracking can be a powerful method to reveal when and where birds are exposed to enhanced risk and mortality during their annual cycles.     

What are the policy priorities for sustaining ecological processes? A case study from Victoria,Australia

Summary Developments in ecological theory indicate that ecological processes have major implications for sustaining biodiversity and the provision of ecosystem services. Consequently, conservation actions that focus solely on particular species, vegetation communities, habitats or sites (‘assets’) are unlikely to be effective over the long term unless the ecological processes that support them continue to function. Efforts to sustain biodiversity must embrace both ‘assets’ and ‘process‐oriented’ approaches. Existing knowledge about ecological processes, incomplete though it is, has not been adequately considered in government decision making. It is, therefore, necessary to consider how to build consideration of ecological processes into legislative and institutional frameworks, policy and planning processes, and on‐ground environmental management. Drawing on insights from interviews, a facilitated workshop, and a literature review, this paper identifies a suite of policy priorities and associated reforms which should assist in ensuring that ecological processes are given more attention in policy‐making processes. It is concluded that a multi‐pronged approach is required, because there are no ‘silver bullets’ for sustaining ecological processes.     

Velvet worm (Phylum Onychophora) on a sand island,in a wetland: Flushed from a Pleistocene refuge by recent rainfall?

Velvet worms (Onychophora) are restricted to moist, humid microclimates, but are poorly known from south‐east Queensland, Australia, where they are typically rainforest fauna. We made the unlikely observation of one of these invertebrates clinging to floating debris in a wetland on North Stradbroke Island. Palaeoecology of this wetland reveals that it once was within rainforest and has remained moist for at least the past 80 000 years, thus potentially harbouring an onychophoran population as a relic of a past broader, rainforest distribution. The presence of this animal, floating in the wetland, can be explained by recent climate, since the wetland filled following heavy rainfall shortly before the observation. This highlights the importance of groundwater‐fed wetlands as evolutionary refugia for moisture‐dependent biota.     

Polyploidy and microsatellite variation in the relict tree Prunus lusitanica L.: how effective are refugia in preserving genotypic diversity of clonal taxa?

Refugia are expected to preserve genetic variation of relict taxa, especially in polyploids, because high gene dosages could prevent genetic erosion in small isolated populations. However, other attributes linked to polyploidy, such as asexual reproduction, may strongly limit the levels of genetic variability in relict populations. Here, ploidy levels and patterns of genetic variation at nuclear microsatellite loci were analysed in Prunus lusitanica, a polyploid species with clonal reproduction that is considered a paradigmatic example of a Tertiary relict. Sampling in this study considered a total of 20 populations of three subspecies: mainland lusitanica (Iberian Peninsula and Morocco), and island azorica (Azores) and hixa (Canary Islands and Madeira). Flow cytometry results supported an octoploid genome for lusitanica and hixa, whereas a 16‐ploid level was inferred for azorica. Fixed heterozygosity of a few allele variants at most microsatellite loci resulted in levels of allelic diversity much lower than those expected for a high‐order polyploid. Islands as a whole did not contain higher levels of genetic variation (allelic or genotypic) than mainland refuges, but island populations displayed more private alleles and higher genotypic diversity in old volcanic areas. Patterns of microsatellite variation were compatible with the occurrence of clonal individuals in all but two island populations, and the incidence of clonality within populations negatively correlated with the estimated timing of colonization. Our results also suggest that gene flow has been very rare among populations, and thus population growth following founder events was apparently mediated by clonality rather than seed recruitment, especially in mainland areas. This study extends to clonal taxa the idea of oceanic islands as important refugia for biodiversity, since the conditions for generation and maintenance of clonal diversity (i.e. occasional events of sexual reproduction, mutation and/or seed immigration) appear to have been more frequent in these enclaves than in mainland areas.     

Assessment of a Syndromic Surveillance System Based on Morbidity Data: Results from the Oscour? Network during a Heat Wave

Background

Syndromic surveillance systems have been developed in recent years and are now increasingly used by stakeholders to quickly answer questions and make important decisions. It is therefore essential to evaluate the quality and utility of such systems. This study was designed to assess a syndromic surveillance system based on emergency departments'' (ED) morbidity rates related to the health effects of heat waves. This study uses data collected during the 2006 heat wave in France.

Methods

Data recorded from 15 EDs in the Ile-de-France (Paris and surrounding area) from June to August, 2006, were transmitted daily via the Internet to the French Institute for Public Health Surveillance. Items collected included diagnosis (ICD10), outcome, and age. Several aspects of the system have been evaluated (data quality, cost, flexibility, stability, and performance). Periods of heat wave are considered the most suitable time to evaluate the system.

Results

Data quality did not vary significantly during the period. Age, gender and outcome were completed in a comprehensive manner. Diagnoses were missing or uninformative for 37.5% of patients. Stability was recorded as being 99.49% for the period overall. The average cost per day over the study period was estimated to be €287. Diagnoses of hyperthermia, malaise, dehydration, hyponatremia were correlated with increased temperatures. Malaise was most sensitive in younger and elderly adults but also the less specific. However, overall syndrome groups were more sensitive with comparable specificity than individual diagnoses.

Conclusion

This system satisfactorily detected the health impact of hot days (observed values were higher than expected on more than 90% of days on which a heat alert was issued). Our findings should reassure stakeholders about the reliability of health impact assessments during or following such an event. These evaluations are essential to establish the validity of the results of syndromic surveillance systems.