scholarly journals Comprehensive analytical approaches reveal species‐specific search strategies in sympatric apex predatory sharks

Ecography ◽  
2021 ◽  
Vol 44 (10) ◽  
pp. 1544-1556 ◽  
Author(s):  
Hannah J. Calich ◽  
Jorge P. Rodríguez ◽  
Víctor M. Eguíluz ◽  
Neil Hammerschlag ◽  
Charitha Pattiaratchi ◽  
...  
2019 ◽  
Vol 14 (1) ◽  
pp. 65-67
Author(s):  
Ann Glusker

A Review of: Golder, S., Wright, K., & Loke, Y.K. (2018). The development of search filters for adverse effects of surgical interventions in MEDLINE and Embase. Health Information and Libraries Journal, 35(2), 121-129. https://doi.org/10.1111/hir.12213 Abstract Objective – “To develop and validate search filters for MEDLINE and Embase for the adverse effects of surgical interventions” (p.121). Design – From a universe of systematic reviews, the authors created “an unselected cohort…where relevant articles are not chosen because of the presence of adverse effects terms” (p.123). The studies referenced in the cohort reviews were extracted to create an overall citation set. From this, three equal-sized sets of studies were created by random selection, and used for: development of a filter (identifying search terms); evaluation of the filter (testing how well it worked); and validation of the filter (assessing how well it retrieved relevant studies). Setting – Systematic reviews of adverse effects from the Database of Abstracts of Reviews of Effects (DARE), published in 2014. Subjects – 358 studies derived from the references of 19 systematic reviews (352 available in MEDLINE, 348 available in Embase). Methods – Word and phrase frequency analysis was performed on the development set of articles to identify a list of terms, starting with the term creating the highest recall from titles and abstracts of articles, and continuing until adding new search terms produced no more new records recalled. The search strategy thus developed was then tested on the evaluation set of articles. In this case, using the strategy recalled all of the articles which could be obtained using generic search terms; however, adding specific search terms (such as the MeSH term “surgical site infection”) improved recall. Finally, the strategy incorporating both generic and specific search terms for adverse effects was used on the validation set of articles. Search strategies used are included in the article, as is a list in the discussion section of MeSH and Embase indexing terms specific to or suggesting adverse effects. Main Results – “In each case the addition of specific adverse effects terms could have improved the recall of the searches” (p. 127). This was true for all six cases (development, evaluation and validation study sets, for each of MEDLINE and Embase) in which specific terms were added to searches using generic terms, and recall percentages compared. Conclusion – While no filter can deliver 100% of items in a given standard set of studies on adverse effects (since title and abstract fields may not contain any indication of relevance to the topic), adding specific adverse effects terms to generic ones while developing filters is shown to improve recall for surgery-related adverse effects (similarly to drug-related adverse effects). The use of filters requires user engagement and critical analysis; at the same time, deploying well-constructed filters can have many benefits, including: helping users, especially clinicians, get a search started; managing a large and unwieldy set of citations retrieved; and to suggest new search strategies.


2009 ◽  
Vol 62 (2) ◽  
pp. 283-301 ◽  
Author(s):  
Alec Banks ◽  
Jonathan Vincent

This paper builds on prior research into the application of particle swarm optimisation to autonomous vehicle control in search roles. It examines the use of naturally inspired search strategies to enhance the performance of groups of sensor-based vehicles in applications where there is no knowledge a priori regarding target presence, location, distribution or behaviour (movement). This paper first briefly reviews existing ethological research into search strategies in the natural world, identifying three types of random walk, two multi-phase strategies and two species-specific strategies for further investigation. Experiments are then performed within a simulation environment to compare the performance of naturally inspired strategies with deterministic patterns and random movement, when searching for both static and dynamic targets. Results indicate that performance improvements can be realised, provided that critical relationships within the application domain broadly match those existing in the underlying natural metaphor.


Author(s):  
N. Quillien ◽  
M. C. Nordström ◽  
H. Le Bris ◽  
E. Bonsdorff ◽  
J. Grall

Beach ecosystems extend from dune to offshore areas along most coasts, and provide essential services that are not provided by any other ecosystem. Indeed, sandy systems contain unique biodiversity and supply nursery and foraging areas for numerous commercially important marine species, such as flatfish. However, these systems are threatened by increasing anthropogenic pressure. Green tides (GT, i.e. accumulations of green opportunistic macroalgae) are a major human-induced threat to marine ecosystems, from inshore to nearshore. This eutrophication process greatly affects both benthic invertebrate communities and flatfish communities, within sheltered and non- or microtidal systems. However, the responses of dynamic open macrotidal sandy systems to eutrophication in the form of macroalgal mats are not yet fully understood. In particular, understanding the effects of GT on two connected biological compartments (infauna and flatfish) within two connected habitats (intertidal and subtidal) is crucial. Here, we set out to assess the influence of several environmental variables, including Ulva biomass, on the variability in infauna and flatfish communities in both the intertidal and the subtidal at four sites impacted or not by GT. In total, 110 biodiversity samples were analysed with classic and novel analytical approaches. Our results demonstrate that the presence of GT specifically impacts intertidal macroinvertebrate communities. However, small effects of GT on subtidal infauna communities, as well as on species-specific flatfish at both intertidal and subtidal, were still detectable. Our findings underline the vulnerability of highly dynamic ecosystems exposed to anthropogenic stress, in particular intertidal sandy shores.


2013 ◽  
Vol 70 (12) ◽  
pp. 1845-1857 ◽  
Author(s):  
Daniel L. Yule ◽  
Jean V. Adams ◽  
David M. Warner ◽  
Thomas R. Hrabik ◽  
Patrick M. Kocovsky ◽  
...  

Pelagic fish assessments often combine large amounts of acoustic-based fish density data and limited midwater trawl information to estimate species-specific biomass density. We compared the accuracy of five apportionment methods for estimating pelagic fish biomass density using simulated communities with known fish numbers that mimic Lakes Superior, Michigan, and Ontario, representing a range of fish community complexities. Across all apportionment methods, the error in the estimated biomass generally declined with increasing effort, but methods that accounted for community composition changes with water column depth performed best. Correlations between trawl catch and the true species composition were highest when more fish were caught, highlighting the benefits of targeted trawling in locations of high fish density. Pelagic fish surveys should incorporate geographic and water column depth stratification in the survey design, use apportionment methods that account for species-specific depth differences, target midwater trawling effort in areas of high fish density, and include at least 15 midwater trawls. With relatively basic biological information, simulations of fish communities and sampling programs can optimize effort allocation and reduce error in biomass estimates.


2006 ◽  
Vol 8 (4) ◽  
pp. e25 ◽  
Author(s):  
Monika Kastner ◽  
Nancy L Wilczynski ◽  
Cindy Walker-Dilks ◽  
Kathleen Ann McKibbon ◽  
Brian Haynes

Author(s):  
Linda Sicko-Goad

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.


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