scholarly journals Periwinkle (Gastropoda: Littorinidae) habitat selection and its impact upon microalgal populations

1999 ◽  
Vol 59 (2) ◽  
pp. 211-218 ◽  
Author(s):  
M. APOLINÁRIO ◽  
R. COUTINHO ◽  
M. H. BAETA-NEVES
Keyword(s):  
Habitat Selection ◽  
Food Availability ◽  
Rocky Shore ◽  
Grazing Pressure ◽  
Sessile Invertebrate ◽  
The Impact ◽  
Selection Of ◽  
Intertidal Level ◽  
Chthamalus Bisinuatus

The present study examines habitat selection and grazing pressure of the periwinkle Nodilittorina lineolata (Gmelin, 1791) on the rocky shore of Arraial do Cabo, RJ, Brazil (lat. 23°S, long. 43°W). Transfer experiments suggest that periwinkles actively select the mid intertidal, where the cirripede Chthamalus bisinuatus Pilsbry is the dominant sessile invertebrate. We also conducted a caging experiment in the middle intertidal, manipulating grazers and light, to assess the impact of grazing upon microalgal density. Grazing pressure significantly reduced microalgal abundance at the mid-intertidal level, suggesting that food availability plays an important role in the habitat selection of periwinkles on the studied shore.

scholarly journals Impact of Soil Moisture and Mowing Height on Ataenius spretulus (Coleoptera: Scarabaeidae) Selection of Golf Course Turf Habitat in Choice Tests

HortScience ◽  
2006 ◽  
Vol 41 (2) ◽  
pp. 459-462 ◽  
Author(s):  
Young-Ki Jo ◽  
David R. Smitely
Keyword(s):  
Soil Moisture ◽  
Habitat Selection ◽  
Cultural Practices ◽  
The Other ◽  
Growth Chamber ◽  
Golf Course ◽  
Ovipositional Preference ◽  
Choice Tests ◽  
The Impact ◽  
Selection Of

Ataenius spretulus (Haldeman) (Coleoptera: Scarabaeidae) is the most common grub in golf course fairways in Michigan. Ataenius spretulus grubs are 3- to 10-fold more abundant in golf course fairways (mowed at a height of 1.5 cm) than in the roughs (mowed at a height of 5.0 cm or higher). Predation and infection by Paenibacillus sp. were previously reported to be greater in the rough, and may partially explain outbreaks of A. spretulus grubs in golf course fairways. In addition to natural enemies, cultural practices of irrigation and mowing could also be important factors, especially if A. spretulus prefers to oviposit in the fairway over the rough. In this paper we examine the impact of soil moisture and mowing height on oviposition and habitat selection. In a greenhouse experiment where A. spretulus adults were given a choice of turf maintained at fairway or rough height, no ovipositional preference for one or the other was observed. In three different growth chamber experiments where adults were allowed to choose among fairway or rough turf plugs held in soil at different moisture levels, adults preferred turf plugs in soil at a volumetric moisture content of 13% to 26% over turf plugs in soil at 8% to 9% moisture for their habitat selection. We conclude from these greenhouse and growth chamber experiments that A. spretulus adults do not choose turf habitat based on mowing height, but may be influenced by soil moisture levels.

Fine-scale habitat selection by adult female swamp wallabies (Wallabia bicolor)

2008 ◽  
Vol 56 (5) ◽  
pp. 305 ◽  
Author(s):  
Matthew Swan ◽  
Julian Di Stefano ◽  
Andrew Greenfield ◽  
Graeme Coulson
Keyword(s):  
Logistic Regression ◽  
Habitat Selection ◽  
Food Availability ◽  
Adult Female ◽  
Food Resources ◽  
Food Abundance ◽  
Fine Scale ◽  
Factors Influencing ◽  
Wallabia Bicolor ◽  
Selection Of

Animals typically use habitat in a non-random way, but the factors influencing habitat selection may change throughout the 24-h cycle. In this study, we quantified resources at used and available locations to test two predictions about the fine-scale habitat selection of seven adult female swamp wallabies (Wallabia bicolor). We predicted that selection would be (i) non-random and (ii) differ between diurnal and nocturnal periods with respect to both food and shelter. Variables quantifying food abundance and lateral cover were recorded at 56 diurnal, 17 nocturnal and 143 randomly selected available locations. Logistic regression indicated that diurnal habitat selection was positively correlated with lateral cover, and the cover of trees, shrubs and forbs, whereas nocturnal selection was positively correlated with forb cover only. Diurnal locations had more lateral cover than nocturnal locations. The data were consistent with our first prediction, but only partially supported our second. At a fine scale, diurnal habitat selection was influenced by the co-availability of shelter and food resources, whereas nocturnal selection was influenced by food availability only, indicating that factors influencing habitat selection changed throughout the 24-h cycle.

scholarly journals FROM THE TORREY CANYON TO TODAY: A 50 YEAR RETROSPECTIVE OF RECOVERY FROM THE OIL SPILL AND INTERACTION WITH CLIMATE-DRIVEN FLUCTUATIONS ON CORNISH ROCKY SHORES

2017 ◽  
Vol 2017 (1) ◽  
pp. 74-103 ◽  
Author(s):  
Stephen J. Hawkins ◽  
Ally J. Evans ◽  
Jon Moore ◽  
Mark Whittington ◽  
Kathryn Pack ◽  
...  
Keyword(s):  
Rocky Shore ◽  
Oil Spills ◽  
Global Climate ◽  
Grazing Pressure ◽  
Spatial And Temporal Variation ◽  
Rocky Shores ◽  
Marine Biological Association ◽  
Key Species ◽  
The Impact

ABSTRACT The Torrey Canyon was wrecked in 1967 with 117,000 tons of crude oil on board. The Plymouth Laboratory of the Marine Biological Association (MBA) of the UK was mobilized to deal with this environmental catastrophe. Many of the rocky shores affected by the spill and unaffected control sites had been studied by staff from the MBA, with A.J. and E.C. Southward charting fluctuations of rocky shore fauna and flora from the early 1950s – particularly barnacles – in relation to climate. Thus a baseline existed to help judge recovery of rocky shores from the beached oil and application of toxic first generation dispersants. A reminder is given of the initial acute impacts of the oil and its treatment by dispersants, and the first ten years of observations on recovery of shore communities. Subsequent follow-up work in the 1980s and 1990s suggested recovery took up to 15 years on the shore (Porthleven) subject to the most severe dispersant application. In contrast, recovery occurred in 2–3 years at Godrevy, a site where dispersants were not applied due to concerns about the impact on seals. The dispersants killed the dominant grazer, limpets of the genus Patella, leading to massive subsequent colonisation by seaweeds. The resulting canopy of fucoid algae (“rockweed” or “wrack”) facilitated dense recruitment of limpets. These subsequently grazed the seaweeds down, before the starving limpets largely died off after migrating across the shore in search of food. This reduction in limpet numbers and grazing pressure then prompted a further bloom of algae. There was then a return to normal levels of spatial and temporal variation of key species of seaweeds and limpets fluctuations charted at Porthleven from the mid 1980s to 2016. Comparisons are made with other oil spills for which long-term recovery has been assessed. Lessons learnt from observations stretching back 60 years, both before and after the spill, for rocky shore monitoring are highlighted – especially the need for broad-scale and long-term monitoring to separate out local impacts (such as oil spills) from global climate-driven change.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

Seasonal habitat selection of an expanding sika deer Cervus nippon population in eastern Hokkaido, Japan

2003 ◽  
Vol 9 (1) ◽  
pp. 141-153 ◽  
Author(s):  
Mayumi Sakuragi ◽  
Hiromasa Igota ◽  
Hiroyuki Uno ◽  
Koichi Kaji ◽  
Masami Kaneko ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Sika Deer ◽  
Cervus Nippon ◽  
Selection Of

Factors of Habitat Selection of Acheulean Sites at Ramat Yiron, Israel

Paléorient ◽  
1981 ◽  
Vol 7 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Amiel Brosh ◽  
M. Ohel
Keyword(s):  
Habitat Selection ◽  
Selection Of

Impact of removing ESBL designation from culture reports on the selection of antibiotics for the treatment of infections associated with ESBL-producing organisms

2020 ◽  
Vol 41 (5) ◽  
pp. 604-607 ◽  
Author(s):  
Mark D. Lesher ◽  
Cory M. Hale ◽  
Dona S. S. Wijetunge ◽  
Matt R. England ◽  
Debra S. Myers ◽  
...  
Keyword(s):  
Antimicrobial Stewardship ◽  
Antibiotic Prescribing ◽  
The Impact ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor ◽  
Selection Of

AbstractWe characterized the impact of removal of the ESBL designation from microbiology reports on inpatient antibiotic prescribing. Definitive prescribing of carbapenems decreased from 48.4% to 16.1% (P = .01) and β-lactam–β-lactamase inhibitor combination increased from 19.4% to 61.3% (P = .002). Our findings confirm the importance of collaboration between microbiology and antimicrobial stewardship programs.

scholarly journals The Impact of Alkaloid-Producing Epichloë Endophyte on Forage Ryegrass Breeding: A New Zealand Perspective

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 158
Author(s):  
Colin Eady
Keyword(s):  
Seed Production ◽  
Health Issues ◽  
Abiotic Stressors ◽  
Livestock Health ◽  
The Right ◽  
The Impact ◽  
The Relationship ◽  
And Storage ◽  
Selection Of ◽  
Epichloë Endophyte

For 30 years, forage ryegrass breeding has known that the germplasm may contain a maternally inherited symbiotic Epichloë endophyte. These endophytes produce a suite of secondary alkaloid compounds, dependent upon strain. Many produce ergot and other alkaloids, which are associated with both insect deterrence and livestock health issues. The levels of alkaloids and other endophyte characteristics are influenced by strain, host germplasm, and environmental conditions. Some strains in the right host germplasm can confer an advantage over biotic and abiotic stressors, thus acting as a maternally inherited desirable ‘trait’. Through seed production, these mutualistic endophytes do not transmit into 100% of the crop seed and are less vigorous than the grass seed itself. This causes stability and longevity issues for seed production and storage should the ‘trait’ be desired in the germplasm. This makes understanding the precise nature of the relationship vitally important to the plant breeder. These Epichloë endophytes cannot be ‘bred’ in the conventional sense, as they are asexual. Instead, the breeder may modulate endophyte characteristics through selection of host germplasm, a sort of breeding by proxy. This article explores, from a forage seed company perspective, the issues that endophyte characteristics and breeding them by proxy have on ryegrass breeding, and outlines the methods used to assess the ‘trait’, and the application of these through the breeding, production, and deployment processes. Finally, this article investigates opportunities for enhancing the utilisation of alkaloid-producing endophytes within pastures, with a focus on balancing alkaloid levels to further enhance pest deterrence and improving livestock outcomes.

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