Consistent predictors of microbial community composition across spatial scales in grasslands reveal low context-dependency.

Environmental circumstances shaping soil microbial communities have been studied extensively. However, due to disparate study designs, it has been difficult to resolve whether a globally consistent set of predictors exists, or context-dependency prevails. Here, we used a network of 18 grassland sites (11 of those containing regional plant productivity gradients) to examine (i) if similar abiotic or biotic factors predict both large-scale (across sites) and regional-scale (within sites) patterns in bacterial and fungal community composition, and (ii) if microbial community composition differs consistently at two levels of regional plant productivity (low vs. high). Our results revealed that bacteria were associated with particular soil properties (such as base saturation) and both bacteria and fungi were associated with plant community composition across sites and within the majority of sites. Moreover, a discernible microbial community signal emerged, clearly distinguishing high and low-productivity soils across different grasslands independent of their location in the world. Hence, regional productivity differences may be typified by characteristic soil microbial communities across the grassland biome. These results could encourage future research aiming to predict the general effects of global changes on soil microbial community composition in grasslands and to discriminate fertile from infertile systems using generally applicable microbial indicators.

New Zealand's vocational Rural Hospital Medicine Training Programme: the first ten years.

AIMS: The Rural Hospital Medicine Training Programme (RHMTP) was established in 2008 to develop New Zealand's rural hospital medical workforce. This study evaluates the RHMTP's first 10-year outcomes. METHODS: A mixed-methods descriptive study. Database interrogation of: the Royal New Zealand College of General Practitioners records; University of Otago's e-Vision; the Medical Council of New Zealand's register of doctors. A survey of trainees who had graduated or withdrew from the programme. Survey questions included: current scope and place of employment; undergraduate rural experience; and trainee experiences. RESULTS: From 2009-2018, 98 doctors entered the RHMTP: 29 graduated, 20 withdrew and 49 are active registrars. Of the graduates, more than half (17/29) also completed GP training. Overall survey response rate: 80% (39/49). Graduate response rate: 97% (28/29). 92% (24/26) of currently practising graduates are working in rural New Zealand, mostly (22/24) in rural hospitals. Trainees value the RHMTP's flexibility and breadth of clinical exposure. The main challenges relate to a lack of alignment of training requirements and funding. CONCLUSIONS: In its first decade, the RHMTP has been successful in generating a rural hospital workforce and the programme is steadily growing. Attention to existing barriers is needed to ensure the RHMTP can reach its potential to benefit all of New Zealand's rural communities.

Response to Comment on "Worldwide evidence of a unimodal relationship between productivity and plant species richness".

Tredennick et al. criticize one of our statistical analyses and emphasize the low explanatory power of models relating productivity to diversity. These criticisms do not detract from our key findings, including evidence consistent with the unimodal constraint relationship predicted by the humped-back model and evidence of scale sensitivities in the form and strength of the relationship.

Plant ecology. Worldwide evidence of a unimodal relationship between productivity and plant species richness.

The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it. Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents. The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity.