The human intestine is colonised by 1013 to 1014 micro-organisms, the vast majority of which belong to the phyla Firmicutes and Bacteroidetes. Although highly stable over time, the composition and activities of the microbiota may be influenced by a number of factors including age, diet and antibiotic treatment. Although perturbations in the composition or functions of the microbiota are linked to inflammatory and metabolic disorders (e.g. inflammatory bowel diseases, irritable bowel syndrome and obesity), it is unclear at this point whether these changes are a symptom of the disease or a contributing factor. A better knowledge of the mechanisms through which changes in microbiota composition (dysbiosis) promote disease states is needed to improve our understanding of the causal relationship between the gut microbiota and disease. While evidence of the preventive and therapeutic effects of probiotic strains on diarrhoeal illness and other intestinal conditions is promising, the exact mechanisms of the beneficial effects are not fully understood. Recent studies have raised the question of whether non-viable probiotic strains can confer health benefits on the host by influencing the immune system. As the potential health effect of these non-viable bacteria depends on whether the mechanism of this effect is dependent on viability, future research needs to consider each probiotic strain on a case-by-case basis. The present review provides a comprehensive, updated overview of the human gut microbiota, the factors influencing its composition and the role of probiotics as a therapeutic modality in the treatment and prevention of diseases and/or restoration of human health.

Crop-raiding by primates and bushpigs Potamochoerus porcus is a major cause of human–wildlife conflict around Budongo Forest Reserve, Uganda. In 2006–2007 a project was initiated, with farmer participation, to investigate the efficacy of on-farm techniques to reduce crop-raiding, including guarding and early-warning techniques, fences, plant barriers, trenches, lights and nets. Here, farmers' perceptions of the effectiveness and sustainability of these deterrents were evaluated using semi-structured interviews and direct observations. Factors important to farmers in effective, sustainable and locally appropriate crop-raiding mitigation are that deterrents be cost-effective, easily manipulated, improve guarding efficiency and require minimal labour inputs. Farmers reported paid guards, guard dogs, wire fences, lights and bells/alarms as most effective. This differs from observations that farmers independently maintained certain deterrents that they presumably considered valuable, namely wire fences, guard dogs, bells/alarms, trenches, lights and nets. This evaluation demonstrates the importance of farmers' participation and perceptions in the viability and uptake of crop-raiding deterrents, and the importance of assessing conflict mitigation trials over the long term.

The 2001/02 austral summer was the warmest summer on record in Taylor Valley, Antarctica, (∼78° S) since continuous records of temperature began in 1985. The highest stream-flows ever recorded in the Onyx River, Wright Valley, were also recorded that year (the record goes back to the 1969/70 austral summer). In early January 2002, a groundwater seep was observed flowing in the southwest portion of Taylor Valley. This flow has been named ‘Wormherder Creek’ (WHC) and represents an unusual event, probably occurring on a decadal time-scale. The physical characteristics of this feature suggest that it may have flowed at other times in the past. Other groundwater seeps, emanating from the north-facing slope of Taylor Valley, were also observed. Little work has been done previously on these very ephemeral seeps, and the source of water is unknown. These features, resembling recently described features on Mars, represent the melting of subsurface ice. The Martian features have been interpreted as groundwater seeps. In this paper we compare the chemistry of the WHC groundwater seep to that of the surrounding streams that flow every austral summer. The total dissolved solids content of WHC was ∼6 times greater than that of some nearby streams. The Na : Cl and SO4 : Cl ratios of the seep waters are higher than those of the streams, but the Mg : Cl and HCO3 : Cl ratios are lower, indicating different sources of solutes to the seeps compared to the streams. The enrichment of Na and SO4 relative to Cl may suggest significant dissolution of mirabilite within the previously unwetted soil. The proposed occurrence of abundant mirabilite in higher-elevation soils of the dry valley region agrees with geochemical models developed, but not tested, in the late 1970s. The geochemical data demonstrate that these seeps could be important in ‘rinsing’ the soils by dissolving and redistributing the long-term accumulation of salts, and perhaps improving habitat suitability for soil biota. The H4SiO4 concentration is 2–3 times greater in WHC than in the surrounding streams, indicating a large silicate-weathering component in the seep waters.