Plant Species\u27 Origin Predicts Dominance and Response to Nutrient Enrichment and Herbivores in Global Grasslands

Exotic species dominate many communities; however the functional significance of species\u27 biogeographic origin remains highly contentious. This debate is fuelled in part by the lack of globally replicated, systematic data assessing the relationship between species provenance, function and response to perturbations. We examined the abundance of native and exotic plant species at 64 grasslands in 13 countries, and at a subset of the sites we experimentally tested native and exotic species responses to two fundamental drivers of invasion, mineral nutrient supplies and vertebrate herbivory. Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands

Plant species' origin predicts dominance and response to nutrient enrichment and herbivores in global grasslands

Exotic species dominate many communities; however the functional significance of species’ biogeographic origin remains highly contentious. This debate is fuelled in part by the lack of globally replicated, systematic data assessing the relationship between species provenance, function and response to perturbations. We examined the abundance of native and exotic plant species at 64 grasslands in 13 countries, and at a subset of the sites we experimentally tested native and exotic species responses to two fundamental drivers of invasion, mineral nutrient supplies and vertebrate herbivory. Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands

Predicting invasion in grassland ecosystems: is exotic dominance the real embarrassment of richness?

Invasions have increased the size of regional species pools, but are typically assumed to reduce native diversity. However, global-scale tests of this assumption have been elusive because of the focus on exotic species richness, rather than relative abundance. This is problematic because low invader richness can indicate invasion resistance by the native community or, alternatively, dominance by a single exotic species. Here, we used a globally replicated study to quantify relationships between exotic richness and abundance in grass-dominated ecosystems in 13 countries on six continents, ranging from salt marshes to alpine tundra. We tested effects of human land use, native community diversity, herbivore pressure, and nutrient limitation on exotic plant dominance. Despite its widespread use, exotic richness was a poor proxy for exotic dominance at low exotic richness, because sites that contained few exotic species ranged from relatively pristine (low exotic richness and cover) to almost completely exotic-dominated ones (low exotic richness but high exotic cover). Both exotic cover and richness were predicted by native plant diversity (native grass richness) and land use (distance to cultivation). Although climate was important for predicting both exotic cover and richness, climatic factors predicting cover (precipitation variability) differed from those predicting richness (maximum temperature and mean temperature in the wettest quarter). Herbivory and nutrient limitation did not predict exotic richness or cover. Exotic dominance was greatest in areas with low native grass richness at the site- or regional-scale. Although this could reflect native grass displacement, a lack of biotic resistance is a more likely explanation, given that grasses comprise the most aggressive invaders. These findings underscore the need to move beyond richness as a surrogate for the extent of invasion, because this metric confounds monodominance with invasion resistance. Monitoring species’ relative abundance will more rapidly advance our understanding of invasions.This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons Ltd and can be found at: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2486

Profile of members of the Australian Osteopathic Association: part 1 – the practitioners

Objectives: The Research Council of the Australian Osteopathic Association (AOA) identified the need to gather data about the members of the Association as well as ‘who’ and ‘what’ they treat in order to guide strategic planning in research. Methods: A census of two parts was sent to members of the AOA (n ¼ 656). Part 1 focussed on the practitioners and part 2 on the patients. Surveys of specific groups in the osteopathic profession in New Zealand and the United Kingdom as well as earlier Australian surveys were obtained for comparative and temporal analysis. Results: The response rate was 52% of the sample population. The gender was split evenly, and the majority practice was a 32e40 h working week in one (59%) or two (33.8%) locations. They consult an estimated average of 40 patients a week (25% are new patients). In their diagnostic practice, physical examination was considered mostly in the orthopaedic and neurological systems, with a limited consideration of other systems. Referrals for diagnostic investigation were mostly for plain-film radiology. The estimated use of therapeutic modalities had soft tissue, muscle energy, non-high velocity articulation/mobilisation and high velocity manipulation consistently used, with a broad spread of others. Nutritional supplements, exercise and diet/lifestyle changes were all prescribed. Questions about inter-professional relationships revealed that practitioners refer to GPs 68.5% ‘‘occasionally’’ and 19.2% ‘‘frequently’’, masseurs 48.2% ‘‘occasionally’’ and 19.3% ‘‘frequently’’, naturopaths/herbalists 43.4% ‘‘occasionally’’ and 12.0% ‘‘frequently’’, and podiatrists 47.5% ‘‘occasionally’’ and 9.8% ‘‘frequently’’. Referrals were almost exclusively from other patients (96.1% frequently), whilst it was estimated by the respondents that GPs refer occasionally (47.9%) or frequently (17.4%). The sample placed importance on, and attended, continuing education activities, and reported that the most important professional issues were the public and health practitioners’ perception/ignorance of osteopathy followed by the need for evidence into the efficacy of osteopathic management. Conclusions: Part 1 of the survey of a sample of the members of the AOA revealed details of their qualifications and commitment to continuing education. The characteristics of respondents’ practice within a multidisciplinary network, and the utilisation of the diagnostic skills of primary care were revealed. The importance of certain issues facing the Australian osteopathic profession were identified