Biomedical subjects

D Raffaelli

Publications and source records attributed to D Raffaelli.

5 recordsLinked to original sources

PubMed2001

Biodiversity and ecosystem functioning: current knowledge and future challenges.

The ecological consequences of biodiversity loss have aroused considerable interest and controversy during the past decade. Major advances have been made in describing the relationship between species diversity and ecosystem processes, in identifying functionally important species, and in revealing underlying mechanisms. There is, however, uncertainty as to how results obtained in recent experiments scale up to landscape and regional levels and generalize across ecosystem types and processes. Larger numbers of species are probably needed to reduce temporal variability in ecosystem processes in changing environments. A major future challenge is to determine how biodiversity dynamics, ecosystem processes, and abiotic factors interact.

Animals↗

PubMed2001

Consistent patterns and the idiosyncratic effects of biodiversity in marine ecosystems.

Revealing the consequences of species extinctions for ecosystem function has been a chief research goal and has been accompanied by enthusiastic debate. Studies carried out predominantly in terrestrial grassland and soil ecosystems have demonstrated that as the number of species in assembled communities increases, so too do certain ecosystem processes, such as productivity, whereas others such as decomposition can remain unaffected. Diversity can influence aspects of ecosystem function, but questions remain as to how generic the patterns observed are, and whether they are the product of diversity, as such, or of the functional roles and traits that characterize species in ecological systems. Here we demonstrate variable diversity effects for species representative of marine coastal systems at both global and regional scales. We provide evidence for an increase in complementary resource use as diversity increases and show strong evidence for diversity effects in naturally assembled communities at a regional scale. The variability among individual species responses is consistent with a positive but idiosyncratic pattern of ecosystem function with increased diversity.

Animals↗

PubMed2001

Adjunctive osteopathic manipulative treatment in women with depression: a pilot study.

The authors assessed the impact of osteopathic manipulative treatment (OMT) as an adjunct to standard psychiatric treatment of women with depression. Premenopausal women with newly diagnosed depression were randomly assigned to either control (osteopathic structural examination only; n = 9) or treatment group (OMT; n = 8). Both groups received conventional therapy consisting of the antidepressant paroxetine (Paxil) hydrochloride plus weekly psychotherapy for 8 weeks. Attending psychiatrists and psychologists were blinded to group assignments. No significant differences existed between groups for age or severity of disease. After 8 weeks, 100% of the OMT treatment group and 33% of the control group tested normal by psychometric evaluation. No significant differences or trends were observed between groups in levels of cytokine production (IL-1, IL-10, IL-2, IL-4, and IL-6) or in levels of anti-HSV-1, anti-HSV-2, and anti-EBV antibody. There was no pattern to the osteopathic manipulative structural dysfunctions recorded. The findings of this pilot study indicate that OMT may be a useful adjunctive treatment for alleviating depression in women.

Adult↗

PubMed2000

Trends in research on shallow water food webs.

Making sense of the spider-web networks of interactions between species in food webs has been a major pre-occupation of ecologists over the last 60 years. This review describes the early attempts to reduce this complexity through the grouping of individual taxa into functional categories (such as trophic levels), through adopting the energy flow or systems approach as epitomised by the International Biological Programme, and most recently by the derivation of web statistics by food web theorists. The strengths and weaknesses of these approaches are discussed in relation to empirical field experiments for unravelling the processes responsible for organising communities and an assessment made of the representation of these approaches in the marine biological literature.

Journal Article↗

PubMed2000

Effects of macroalgal mats on intertidal sandflats: an experimental study.

The growth of green macroalgal mats is becoming increasingly common in many marine intertidal habitats. While the ecological effects of such growth has previously been experimentally investigated on mudflats, such experiments have rarely been performed on intertidal sandflats. This study investigated the ecological effects of macroalgal cover on a moderately exposed intertidal sandflat, Drum Sands, Firth of Forth, Scotland. Artificially implanted Enteromorpha prolifera (Müller) caused marked changes in the macrobenthos, together with significant changes in all the measured sediment variables. After 6 weeks, the weed significantly increased the macrofaunal diversity. The numbers of Pygospio elegans (Claparède) were significantly reduced under weed mats, while those of Capitella capitata (Fabricius), oligochaetes and gammarids increased. Percent water, organics and silt/clay contents, medium phi and sorting coefficient significantly increased in the sediments under weed mats which also became significantly more reduced between 1 and 8 cm depth. After 20 weeks, a macrofaunal community numerically dominated by C. capitata, with a significantly reduced diversity, was present under weed mats, while sediment variables were no longer significantly different from controls. The negative effect of E. prolifera on P. elegans was mainly due to larval filtering, suggesting that weed is likely to have detrimental effects on population maintenance of most species which rely on planktonic larval recruitment. These results are broadly similar to those obtained from algal manipulation experiments performed in much more sheltered, muddier environments. We suggest that a predictable deterioration in environmental quality results from the growth of macroalgal mats in soft-bottom habitats. However, the longer term effects of such algal growth are less predictable and depend upon the spatial distributions of the most abundant infaunal species and the spatial heterogeneity of weed mat establishment.

Journal Article↗