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Eroded Areas (eroded + area)

Distribution by Scientific Domains

Earth and Environmental Science	75%

Selected Abstracts

Quantifying sponge erosions in Western Australian pearl oyster shells

AQUACULTURE RESEARCH, Issue 9 2010
Sabine Daume
Abstract This paper describes several methods to estimate the amount of sponge erosion in pearl oyster shells (Pinctada maxima Jameson, 1901). Internal erosion can be calculated from non-destructive surface area estimates because a clear relationship was found between the eroded area on the surface of the shells and internal erosions. Grading shells into three different categories, according to the severity of erosion, also proved to be a suitable method to quickly assess the amount of sponge erosions. All methods were more accurate in shells with larger amounts of erosions. Using the described methods, the Lacepedes fishing ground was more diverse in bioeroding sponge species compared with sites at the 80-Mile fishing ground locations. Pione velans Hentschel, 1909 was the dominant bioeroding sponge species but Cliona dissimilis Ridley and Dendy, 1886 eroded more shell material than P. velans. Observed patterns suggest that P. velans had a more recent recruitment than C. dissimilis. We suggest that visual grading together with estimates from the shell surface will be sufficient to determine the general long-term trends in bioeroding sponge severity. However, results of monitoring programmes need to be supplemented by histological examination to confirm sponge activity and species identity. [source]

Plant traits enabling survival in Mediterranean badlands in northeastern Spain suffering from soil erosion

JOURNAL OF VEGETATION SCIENCE, Issue 4 2008
Joaquín Guerrero-Campo
Abstract Question: This study analysed the effect of severe soil erosion on species composition of plant communities by favouring species showing certain growth forms, root-sprouting and clonal growth abilities. Location: The study area was located between the middle Ebro Valley and the Pre-Pyrenees (northeastern Spain). Methods: Root-sprouting and shoot-rooting abilities, clonal reproduction and growth form were assessed for the 123 most common plant species from eroded lands in the study area. We obtained 260 vegetation relevés in three different substrata (gypsum outcrops, Miocene clays and Eocene marls) on areas with different degrees of soil erosion. The frequency of every plant trait in each relevé was estimated according to species presence. The effect of soil erosion on the frequency of plant attributes was assessed by correlation analyses. Results: Bipolar, non-clonal plants and annual species decreased their frequency with increasing soil erosion in the three substrata analyzed, whereas root-sprouters and woody plants (mostly sub-shrubs) increased their frequency in most of the substrata analysed. Conclusions: Woody sub-shrubs, root-sprouters and clonal species are favoured in eroded lands in NE Spain. Bipolar species and annual plants might not be plastic enough to survive the high stress and frequent disturbances prevailing in such eroded areas. [source]

Biodiversity of semi-arid Mediterranean grasslands: Impact of grazing and afforestation

APPLIED VEGETATION SCIENCE, Issue 2 2007
M.A. Alrababah
Zohary & Feinbrun (1966,1986) Abstract Question: What is the impact of grazing and/or afforestation on grassland diversity, species composition and cover parameters? Location: Semi-arid Mediterranean grasslands of Jordan. Methods: Vegetation, litter, bare soil and rock cover were compared among four management types , free grazing and protected from grazing with three levels of tree cover. Species composition, plant cover, species richness and evenness were used to evaluate differences in vegetation among management types. Species composition differences among management types were also investigated. Results: Semi-arid Mediterranean grasslands harbour appreciable levels of plant biodiversity. Grazing did not affect plant diversity, indicating the high resilience against and adaptation to grazing; however,grazing affected species composition and cover parameters. Afforestation seems to protect soil through higher litter cover but its impact on plant biodiversity was negative and markedly affected species composition. Conclusions: Neither protection from grazing or massive afforestation alone are sufficient for conserving biodiversity in this system. A management model is suggested where the landscape should be maintained as a mosaic of four management types: complete protection from grazing, grazing rotation, planting sparse trees in eroded areas and revegetating degraded areas using native, herbaceous and grazing tolerant species. [source]

Is blistering distal dactylitis a variant of bullous impetigo?

CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 3 2007
N. S. Scheinfeld
Summary Blistering distal dactylitis (BDD) manifests as acral oval bullae 10,30 mm in diameter, and is caused by infection with Gram-positive bacteria. BDD was first linked to infection with group A ,-haemolytic streptococcus in children, but has more recently linked to Staphylococcus aureus and noted in adults. BDD most commonly occurs as bullae on the volar fat pads of the fingers but can occur on the proximal phalangeal and palmar areas of the hands and can manifest as multiple bullae. The bullae can evolve into erosions over the course of several days. BDD can coexist with and may be secondary to clinically imperceptible infections of the nasopharynx, conjunctiva or anus, which underlines the need for systemic antibiotic therapy. Multiple bullae appear to be a predictor that S. aureus is the causative agent of a case of BDD. When BDD is suspected, treatment involves: (i) incision and drainage of bullae, (ii) wet to dry compresses to dry the eroded areas, and (iii) a course of a ,-lactamase-resistant antibiotics, necessary because S. aureus, now found to be a common cause of BDD, is usually resistant to penicillin. No treatment failures have been reported. [source]