A review of the biology of European cockles (Cerastodermaspp.)

Author(s):  
Shelagh K. Malham ◽  
Thomas H. Hutchinson ◽  
Matt Longshaw

This review examines the biology of the two main cockle speciesCerastoderma eduleandC. glaucumfound in coastal areas around the north-east Atlantic from Norway to Morocco and through the Baltic, Mediterranean and Black Sea. It considers those factors in particular that impact on the overall health and survival of individuals as well as populations. Methods for the discrimination of the species are reviewed as well as the approaches being taken to delineate different populations, which is crucial to appropriately manage individual fisheries. Cockle populations generally undergo sexual maturation during their second summer and sexes are separate. Eggs are pelagic, with larvae being both benthic and pelagic before settling on the sediment and becoming benthic adults. However, data are lacking on basic larval biology and dispersal mechanisms. Data are provided on predator–prey relationships including information on types of food of importance to cockles. Main predators of cockles include brown shrimp, shore crabs, gastropods, polychaetes, fish and a variety of birds and these can be important in structuring cockle populations. Predation of larval cockles by adult cockles through larviphagy can lead to reductions of up to 40% of the population. Cockles are sensitive to a wide range of chemical contaminants but few data are published on impacts on cockles, in particular larval stages. The review concludes with an assessment of future climate change scenarios on cockles and considers some areas of future research required to preserve this ecologically and economically important species.

2006 ◽  
Vol 30 (6) ◽  
pp. 751-777 ◽  
Author(s):  
Risto K. Heikkinen ◽  
Miska Luoto ◽  
Miguel B. Araújo ◽  
Raimo Virkkala ◽  
Wilfried Thuiller ◽  
...  

Potential impacts of projected climate change on biodiversity are often assessed using single-species bioclimatic ‘envelope’models. Such models are a special case of species distribution models in which the current geographical distribution of species is related to climatic variables so to enable projections of distributions under future climate change scenarios. This work reviews a number of critical methodological issues that may lead to uncertainty in predictions from bioclimatic modelling. Particular attention is paid to recent developments of bioclimatic modelling that address some of these issues as well as to the topics where more progress needs to be made. Developing and applying bioclimatic models in a informative way requires good understanding of a wide range of methodologies, including the choice of modelling technique, model validation, collinearity, autocorrelation, biased sampling of explanatory variables, scaling and impacts of non-climatic factors. A key challenge for future research is integrating factors such as land cover, direct CO2 effects, biotic interactions and dispersal mechanisms into species-climate models. We conclude that, although bioclimatic envelope models have a number of important advantages, they need to be applied only when users of models have a thorough understanding of their limitations and uncertainties.


2021 ◽  
Vol 9 (4) ◽  
pp. 862
Author(s):  
Vittoria Catara ◽  
Jaime Cubero ◽  
Joël F. Pothier ◽  
Eran Bosis ◽  
Claude Bragard ◽  
...  

Bacteria in the genus Xanthomonas infect a wide range of crops and wild plants, with most species responsible for plant diseases that have a global economic and environmental impact on the seed, plant, and food trade. Infections by Xanthomonas spp. cause a wide variety of non-specific symptoms, making their identification difficult. The coexistence of phylogenetically close strains, but drastically different in their phenotype, poses an added challenge to diagnosis. Data on future climate change scenarios predict an increase in the severity of epidemics and a geographical expansion of pathogens, increasing pressure on plant health services. In this context, the effectiveness of integrated disease management strategies strongly depends on the availability of rapid, sensitive, and specific diagnostic methods. The accumulation of genomic information in recent years has facilitated the identification of new DNA markers, a cornerstone for the development of more sensitive and specific methods. Nevertheless, the challenges that the taxonomic complexity of this genus represents in terms of diagnosis together with the fact that within the same bacterial species, groups of strains may interact with distinct host species demonstrate that there is still a long way to go. In this review, we describe and discuss the current molecular-based methods for the diagnosis and detection of regulated Xanthomonas, taxonomic and diversity studies in Xanthomonas and genomic approaches for molecular diagnosis.


BMJ Leader ◽  
2021 ◽  
pp. leader-2020-000403
Author(s):  
Victoria Smith ◽  
Claire Maxwell ◽  
Lisa Robinson

ObjectivesSelection of effective leadership styles within healthcare is linked to high quality, safe care for patients. Within the literature attention has been given to medical and nursing professions, failing to acknowledge the contribution made by physiotherapy leaders. This study aims to consider the leadership styles used by physiotherapists in a designated leadership role, specifically exploring the barriers they face and the strategies employed to overcome current leadership dilemmas.DesignA qualitative, phenomenological design was used. Consent was obtained from each participant for one semistructured interview which was audio recorded and transcribed verbatim. Framework analysis was used to analyse the data.SettingA large National Health Service Foundation Trust within the North East of England.ParticipantsA purposive sample of ten physiotherapy team leaders.ResultsThe theoretical leadership framework that emerged demonstrated the daily tensions experienced by physiotherapy team leaders in regard to being a transactional or transformational leader. Within this, three superordinate themes exist: the individual, the team and the organisation and beyond. Each theme contained barriers and enablers which related to transactional and transformational leadership styles, respectively.ConclusionsThe framework identified gives insight into a group of clinical leaders not yet explored and provides a foundation for the development of leadership behaviours throughout physiotherapy. These clinicians should be supported by senior leaders to develop more transformational styles which have the potential to impact on staff well-being and patient care. Future research should compare these findings with studies involving larger sample sizes that span the health and social care system.


Zootaxa ◽  
2011 ◽  
Vol 3130 (1) ◽  
pp. 30 ◽  
Author(s):  
YUVINKA GARECA ◽  
PATRICK BLANDIN

The geographical distribution of Morpho helenor (Cramer) in Bolivia is mapped from the study of specimens preserved in Bolivian and foreign collections, and from recent field studies in various ecoregions. One subspecies, M. h. theodorus Fruhstorfer, inhabits Amazonian moist forests in the western and northern parts of the country. Another subspecies, M. h. coelestis Butler, is common in moist cloud forests (Bolivian Yungas), but also occurs to the North and North-East. We describe a new subspecies, M. h. prometa ssp. nov., from Southern Andean Yungas. Transition zones between theodorus and coelestis are highlighted, where specimens exhibiting intermediate phenotypes were collected. The pattern of geographic transition from M. h. coelestis to M. h. prometa needs to be documented. M. h. prometa inhabits sub-humid, semideciduous forests, whereas M. h. theodorus and M. h. coelestis live in rainforests. M. h. coelestis populations are found from less than 100 m to more than 1600 m a.s.l.; M. h. theodorus has been collected at more than 1000 m a.s.l.; and M. h. prometa between 500 m and 1400 m a.s.l.. Therefore, Bolivian M. helenor populations are distributed throughout a wide range of ecological contexts: we discuss the habitat plasticity of the species in light of available knowledge of its geographical distribution and habitats in the Neotropical Region.


Author(s):  
M.B. Santos ◽  
G.J. Pierce ◽  
C. Smeenk ◽  
M.J. Addink ◽  
C.C. Kinze ◽  
...  

This paper presents information on the stomach contents of four northern bottlenose whales Hyperoodon ampullatus (Odontoceti: Ziphiidae) from the north-east Atlantic, an area for which there are few recent data on the feeding ecology of this species. Two of these whales were relatively recent strandings, a female stranded in August 1993 at Hargen (the Netherlands) and a male stranded in February 1997 on the island of Tåsinge (Denmark). Stomach content samples were also examined from a juvenile male stranded in November 1885 at Dunbar (Scotland) and a female stranded in August 1956 on the island of Texel (the Netherlands).  Food remains from the four samples consisted almost entirely of cephalopod beaks. Some fish remains were also found in the stomach of the Hargen and Tåsinge whales, and the latter also had crustacean remains in the stomach. The cephalopod prey consisted mainly of oceanic cephalopods: Gonatus sp. (probably G. fabricii, Cephalopoda: Teuthoidea), Taoniuspavo and Histioteuthis sp. for the Dunbar whale; Gonatus and Teuthowenia megalops for the Texel whale; Gonatus for the Hargen whale and Gonatus, T. megalops and Taonius pavo for the Tåsinge whale. Other prey species found in the Tåsinge specimen included the squid Histioteuthis reversa, H. arcturi, and the octopods Vampiroteuthis infernalis and Vitreledonella richardi. Based on the size of the lower beaks, the squid eaten included juvenile and mature individuals of the most important species (Gonatus and Teuthowenia megalops). The fish remains consisted of vertebrae of Gadidae and fish eye lenses (Hargen whale) and two Trisopterus otoliths (Tåsinge whale).  The results from this study are in agreement with those of previous authors in that cephalopods in general, and G. fabricii in particular, are the main prey of the northern bottlenose whale and other toothed whales in northern latitudes.


English Today ◽  
2020 ◽  
pp. 1-10
Author(s):  
Michael Pearce

English dialects demonstrate considerable variation in their pronominal systems (see for example Trudgill & Chambers, 1991 and Hernández, 2011). In England, pronouns in the north east of the country – the urban areas of Tyne and Wear and Teesside and the counties of Durham and Northumberland (hereafter NEE) – are often different from those found in Standard English (SE). The most extensive modern accounts of NEE pronouns are Beal (1993) and Beal, Burbano–Elizondo and Llamas (2012), but because they appear in chapters dealing with a wide range of morphosyntactic topics, the coverage is necessarily brief. This article is able to offer a more detailed overview of the morphology of NEE pronouns, based on a sizeable naturalistic corpus of vernacular writing.


2020 ◽  
Author(s):  
Joanna Struzewska ◽  
Maciej Jefimow ◽  
Paulina Jagiełło ◽  
Maria Kłeczek ◽  
Anahita Sattari ◽  
...  

<p>Regional climate projections are necessary to assess possible changes in the exposure and risk to allow planning the adaptation strategies.</p><p>Projections of temperature and precipitation trends were developed using a consistent methodology and homogeneous datasets to address the needs of up-to-date climate change scenarios for Poland.</p><p>The Euro-Cordex results with the resolution of 0.11deg (about 12.5km) for RCP4.5 and RCP8.5 were downscaled based on various historical gridded datasets (EOBS, ERA5, UERRA and data from IMWM).</p><p>Ensemble analysis was undertaken to assess the projection uncertainty and ensemble mean were calculated for base parameters (daily average, minimum, and maximum temperature and daily precipitation sum) as well as for the number of climate indices.</p><p>We will present spatial and temporal variability of selected climate indices over Poland for subsequent decades. Increase of the annual average temperature is due to the rise in the number of hot days and the reduction of the number of frost days. All temperature indices are characterized by statistically significant trends, strongest for RCP8.5. The most pronounced changes in the frequency and amount of precipitation occur in the north-east of Poland. The total number of days with precipitation increases slightly. The increase in the annual rainfall is due to the increase in the number of days with extreme precipitation.</p><p>Results are presented via an interactive web portal. Further analysis includes the development of projection for solar radiation, wind speed, humidity and snow cover.</p>


Author(s):  
Marie V. Lebour

Two species of Portumnus occur in the Plymouth area, P. biguttatus (Risso) and P. latipes (Pennant). P. biguttatus was the only species recorded when the old fauna list of Plymouth was published (1904), but since then it is known that P. latipes is very common in certain sandy areas (see Plymouth Marine Fauna, 1931), far commoner than P. biguttatus.P. biguttatus is rare and has not been seen since 1906. It was first found by W. Garstang and R. Todd on Drake's Island in Plymouth Sound, burrowing in fine gravel (1905), and two specimens, and are recorded from a sandy patch from the north-east corner of Drake's Island. A female in berry was recorded from the same locality by R. Todd, and L. R. Crawshay dredged one in Cawsand Bay in 1906. Apparently the eggs were not hatched out and the zoea of this species is unknown. In August 1902 R. Gurney obtained a megalopa in the plankton and from it secured the first crab stage. He describes the megalopa as being intensely blue. The cast skin of the megalopa and the crab obtained from it (Fig. 3a-c), which he kindly handed to me, are described in my paper of 1928 (Lebour, 1928c, p. 518, pl. viii, figs. 1–3). There is no reason to doubt the accuracy of the determination, especially because, as shown below, corresponding stages of P. latipes as well as the zoeae are now known and are very distinct, differing considerably from those of P. biguttatus.


2017 ◽  
Author(s):  
Marit Van Tiel ◽  
Adriaan J. Teuling ◽  
Niko Wanders ◽  
Marc J. P. Vis ◽  
Kerstin Stahl ◽  
...  

Abstract. Glaciers are essential hydrological reservoirs, storing and releasing water at various time scales. Short-term variability in glacier melt is one of the causes of streamflow droughts, defined as below normal water availabilities. Streamflow droughts in glacierised catchments have a wide range of interlinked causing factors related to precipitation and temperature on short and long time scales. Climate change affects glacier storage capacity, with resulting consequences for discharge regimes and drought. Future projections of streamflow drought in glacierised basins can, however, strongly depend on the modelling strategies and analysis approaches applied. Here, we examine the effect of different approaches, concerning the glacier modelling and the drought threshold, on the characterisation of streamflow droughts in glacierised catchments. Streamflow is simulated with the HBV-light model for two case study catchments, the Nigardsbreen catchment in Norway and the Wolverine catchment in Alaska, and two future climate change scenarios (RCP4.5 and RCP8.5). Two types of glacier modelling are applied, a constant and dynamical glacier area conceptualisation. Streamflow droughts are identified with the variable threshold level method and their characteristics are compared between two periods, a historical (1975–2004) and future (2071–2100) period. Two existing threshold approaches to define future droughts are employed, (1) the threshold from the historical period and (2) a transient threshold approach, whereby the threshold adapts every year in the future to the changing regimes. Results show that drought characteristics differ among the combinations of glacier area modelling and thresholds. The historical threshold combined with a dynamical glacier area projects extreme increases in drought severity in the future, caused by the regime shift due to a reduction in glacier area. The historical threshold combined with a constant glacier area results in a drastic decrease of the number of droughts. The drought characteristics between future and historic periods are more similar when the transient threshold is used, for both glacier dynamics conceptualisations. With the transient threshold causing factors of future droughts, can be analysed. This study revealed the different effects of methodological choices on future streamflow drought projections and it highlights how the options can be used to analyse different aspects of future droughts: the transient threshold for analysing future drought processes, the historical threshold to assess changes between periods, the constant glacier area to analyse the effect of short term climate variability on droughts and the dynamical glacier area to model realistic future discharges under climate change.


2004 ◽  
Vol 5 ◽  
pp. 99-112 ◽  
Author(s):  
Stefan Piasecki ◽  
John H. Callomon ◽  
Lars Stemmerik

The Jurassic of Store Koldewey comprises a Middle Jurassic succession towards the south and an Upper Jurassic succession towards the north. Both successions onlap crystalline basement and coarse sediments dominate. Three main lithostratigraphical units are recognised: the Pelion Formation, including the Spath Plateau Member, the Payer Dal Formation and the Bernbjerg Formation. Rich marine macrofaunas include Boreal ammonites and the successions are dated as Late Bathonian – Early Callovian and Late Oxfordian – Early Kimmeridgian on the basis of new collections combined with material in earlier collections. Fine-grained horizons and units have been analysed for dinoflagellate cysts and the stratigraphy of the diverse and well-preserved flora has been integrated with the Boreal ammonite stratigraphy. The dinoflagellate floras correlate with contemporaneous floras from Milne Land, Jameson Land and Hold with Hope farther to the south in East Greenland, and with Peary Land in North Greenland and Svalbard towards the north. The Middle Jurassic flora shows local variations in East Greenland whereas the Upper Jurassic flora gradually changes northwards in East Greenland. A Boreal flora occurs in Peary Land and Svalbard. The characteristic and stratigraphically important species Perisseiasphaeridium pannosum and Oligosphaeridium patulum have their northernmost occurrence on Store Koldewey, whereas Taeniophora iunctispina and Adnatosphaeridium sp. extend as far north as Peary Land. Assemblages of dinoflagellate cysts are used to characterise significant regional flooding events and extensive sequence stratigraphic units.


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