272 research outputs found
Spatiotemporal Models of an Estuarine Fish Species to Identify Patterns and Factors Impacting Their Distribution and Abundance
Mediterranean-climate streams and rivers: geographically separated but ecologically comparable freshwater systems
Streams and rivers in mediterranean-climate regions (med-rivers in med-regions) are ecologically unique, with flow regimes reflecting precipitation patterns. Although timing of drying and flooding is predictable, seasonal and annual intensity of these events is not. Sequential flooding and drying, coupled with anthropogenic influences make these med-rivers among the most stressed riverine habitat worldwide. Med-rivers are hotspots for biodiversity in all med-regions. Species in med-rivers require different, often opposing adaptive mechanisms to survive drought and flood conditions or recover from them. Thus, metacommunities undergo seasonal differences, reflecting cycles of river fragmentation and connectivity, which also affect ecosystem functioning. River conservation and management is challenging, and trade-offs between environmental and human uses are complex, especially under future climate change scenarios. This overview of a Special Issue on med-rivers synthesizes information presented in 21 articles covering the five med-regions worldwide: Mediterranean Basin, coastal California, central Chile, Cape region of South Africa, and southwest and southern Australia. Research programs to increase basic knowledge in less-developed med-regions should be prioritized to achieve increased abilities to better manage med-rivers
Trophic consequences of non-native pumpkinseed Lepomis gibbosus for native pond fishes
Introduced non-native fishes can cause considerable adverse impacts on freshwater ecosystems. The pumpkinseed Lepomis gibbosus, a North American centrarchid, is one of the most widely distributed non-native fishes in Europe, having established self-sustaining populations in at least 28 countries, including the U.K. where it is predicted to become invasive under warmer climate conditions. To predict the consequences of increased invasiveness, a field experiment was completed over a summer period using a Control comprising of an assemblage of native fishes of known starting abundance and a Treatment using the same assemblage but with elevated L. gibbosus densities. The trophic consequences of L. gibbosus invasion were assessed with stable isotope analysis and associated metrics including the isotopic niche, measured as standard ellipse area. The isotopic niches of native gudgeon Gobio gobio and roach Rutilus rutilus overlapped substantially with that of non-native L. gibbosus, and were also substantially reduced in size compared to ponds where L. gibbosus were absent. This suggests these native fishes shifted to a more specialized diet in L. gibbosus presence. Both of these native fishes also demonstrated a concomitant and significant reduction in their trophic position in L. gibbosus presence, with a significant decrease also evident in the somatic growth rate and body condition of G. gobio. Thus, there were marked changes detected in the isotopic ecology and growth rates of the native fish in the presence of non-native L. gibbosus. The implications of these results for present and future invaded pond communities are discussed
Situational awareness, relational coordination and integrated care delivery to hospitalized elderly in the Netherlands: A comparison between hospitals
__Abstract__
Background: It is known that interprofessional collaboration is crucial for integrated care delivery, yet we are still unclear about the underlying mechanisms explaining effectiveness of integrated care delivery to older patients. In addition, we lack research comparing integrated care delivery between hospitals. Therefore, this study aims to (i) provide insight into the underlying components 'relational coordination' and 'situational awareness' of integrated care delivery and the role of team and organizational context in integrated care delivery; and (ii) compare situational awareness, relational coordination, and integrated care delivery of different hospitals in the Netherlands. Methods. This cross-sectional study took place in 2012 among professionals from three different hospitals involved in the delivery of care to older patients. A total of 215 professionals filled in the questionnaire (42% response rate).Descriptive statistics and paired-sample t-tests were used to investigate the level of situational awareness, relational coordination, and integrated care delivery in the three different hospitals. Correlation and multilevel analyses were used to investigate the relationship between background characteristics, team context, organizational context, situational awareness, relational coordination and integrated care delivery. Results: No differences in background characteristics, team context, organizational context, situational awareness, relational coordination and integrated care delivery were found among the three hospitals. Correlational analysis revealed that situational awareness (r = 0.30; p < 0.01), relational coordination (r = 0.17; p < 0.05), team climate (r = 0.29; p < 0.01), formal internal communication (r = 0.46; p < 0.01), and informal internal communication (r = 0.36; p < 0.01) were positively associated with integrated care delivery. Stepwise multilevel analyses showed that formal internal communication (p < 0.001) and situational awareness (p < 0.01) were associated with integrated care delivery. Team climate was not significantly associated with integrated care delivery when situational awareness and relational coordination were included in the equation. Thus situational awareness acted as mediator between team climate and integrated care delivery among professionals delivering care to older hospitalized patients. Conclusions: The results of this study show the importance of formal internal communication and situational awareness for quality of care delivery to hospitalized older patients
Aquatic Macroinvertebrate Biodiversity Associated with Artificial Agricultural Drainage Ditches
Agricultural drainage channels and ditches are ubiquitous features in the lowland agricultural landscapes, built primarily to facilitate land drainage, irrigate agricultural crops and alleviate flood risk. Most drainage ditches are considered artificial waterbodies and are not typically included in routine monitoring programmes, and as a result the faunal and floral communities they support are poorly quantified. This paper characterizes the aquatic macroinvertebrate diversity (alpha, beta and gamma) of agricultural drainage ditches managed by an internal drainage board in Lincolnshire, UK. The drainage ditches support very diverse macroinvertebrate communities at both the site (alpha diversity) and landscape scale (gamma diversity) with the main arterial drainage ditches supporting greater numbers of taxa when compared to smaller ditches. Examination of the between site community heterogeneity (beta diversity) indicated that differences among ditches were high spatially and temporally. The results illustrate that both main arterial and side ditches make a unique contribution to aquatic biodiversity of the agricultural landscape. Given the need to maintain drainage ditches to support agriculture and flood defence measures, we advocate the application of principles from ‘reconciliation ecology’ to inform the future management and conservation of drainage ditches
Effect Threshold for Selenium Toxicity in Juvenile Splittail, Pogonichthys macrolepidotus A
In fish, selenium can bioaccumulate and cause adverse impacts. One of the fish species potentially at risk from selenium in the San Francisco Bay (California, USA) is the splittail (Pogonichthys macrolepidotus). Previous studies have derived a whole body NOAEL and LOAEL of 9.0 and 12.9 mg/kg-dw, respectively, for selenium in juveniles. However, the NOAEL/LOAEL approach leaves some uncertainty regarding the threshold of toxicity. Therefore, the raw data from the original experiment was re-analyzed using a logistic regression to derive EC10 values of 0.9 mg/kg-dw in feed, 7.9 mg/kg-dw in muscle, 18.6 mg/kg-dw in liver for juvenile splittail. Selenium concentrations in the dietary items of wild splittail exceed the EC10 values derived here. Thus, deformities previously reported in wild splittail may have resulted from selenium exposures via the food chain
Characterization and evaluation of polymorphic microsatellite markers in the anadromous fish Spirinchus thaleichthys
The predatory Atlantic red drum, Sciaenops ocellatus, has invaded the western Taiwanese coast in the Indo-West Pacific
Estrutura de cardumes da sardinha-verdadeira, Sardinella brasiliensis (Steindachner, 1879), no estado do Rio de Janeiro (Brasil)
Displacement, velocity preference, and substrate use of three native California stream fishes in simulated pulsed flows
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