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Ponta Grossa, Brazil

Maire V.,French National Institute for Agricultural Research | Maire V.,Macquarie University | Gross N.,French National Center for Scientific Research | Gross N.,French National Institute for Agricultural Research | And 8 more authors.
New Phytologist | Year: 2012

Deterministic niche-based processes have been proposed to explain species relative abundance within communities but lead to different predictions: habitat filtering (HF) predicts dominant species to exhibit similar traits while niche differentiation (ND) requires that species have dissimilar traits to coexist. Using a multiple trait-based approach, we evaluated the relative roles of HF and ND in determining species abundances in productive grasslands. Four dimensions of the functional niche of 12 co-occurring grass species were identified using 28 plant functional traits. Using this description of the species niche, we investigated patterns of functional similarity and dissimilarity and linked them to abundance in randomly assembled six-species communities subjected to fertilization/disturbance treatments. Our results suggest that HF and ND jointly determined species abundance by acting on contrasting niche dimensions. The effect of HF decreased relative to ND with increasing disturbance and decreasing fertilization. Dominant species exhibited similar traits in communities whereas dissimilarity favored the coexistence of rare species with dominants by decreasing inter-specific competition. This stabilizing effect on diversity was suggested by a negative relationship between species over-yielding and relative abundance. We discuss the importance of considering independent dimensions of functional niche to better understand species abundance and coexistence within communities. © 2012 New Phytologist Trust. Source

da Silveira Pontes L.,Agronomic Institute of Parana | Magda D.,CNRS Agroecology Lab | Gleizes B.,CNRS Agroecology Lab | Agreil C.,French National Institute for Agricultural Research
Acta Oecologica | Year: 2016

Reconciling the well known benefits of shrubs for forage with environmental goals, whilst preventing their dominance, is a major challenge in rangeland management. Browsing may be an economical solution for shrubby rangelands as herbivore browsing has been shown to control juvenile shrub growth. Less convincing results have been obtained for adult plants, and long-term experiments are required to investigate the cumulative effects on adult plants. We therefore assessed the impact of different levels of browsing intensity on key demographic parameters for a major dominant shrub species (broom, Cytisus scoparius), focusing on adult plants. We assigned individual broom plants to one of three age classes: 3-5 years (young adults); 5-7 years (adults); and 7-9 years (mature adults). These plants were then left untouched or had 50% or 90% of their total edible stem biomass removed in simulated low-intensity and high-intensity browsing treatments, respectively. Morphological, survival and fecundity data were collected over a period of four years. Browsing affected the morphology of individual plants, promoting changes in subsequent regrowth, and decreasing seed production. The heavily browsed plants were 17% shorter, 32% narrower, and their twigs were 28% shorter. Light browsing seemed to control the growth of young adult plants more effectively than that of older plants. Reproductive output was considerably lower than for control plants after light browsing, and almost 100% lower after heavy browsing. High-intensity browsing had a major effect on survival causing high levels of plant mortality. We conclude that suitable browsing practices could be used to modify adult shrub demography in the management of shrub dominance and forage value. © 2015 Elsevier Masson SAS. Source

da Silveira Pontes L.,Agronomic Institute of Parana | Maire V.,University of Quebec at Trois - Rivieres | Schellberg J.,University of Bonn | Louault F.,French National Institute for Agricultural Research
Agronomy for Sustainable Development | Year: 2015

Grassland covers about one quarter of the Earth’s land area and is currently estimated to contribute to the livelihoods of over 800 million people. Grassland provides ecosystem goods and services, mainly through the provisioning of milk and meat. Therefore, the proper use of grasslands will be essential for feeding the nine billion people that will inhabit planet Earth by 2050. In the context of a changing climate, we should better understand the interactions of environment, management and grass crop at individual, community and ecosystem levels. Functional ecology focuses on the roles and functions that species play in the community or ecosystem in which they occur. Functional ecology thus aims to understand how plant species adapt to environmental conditions and how management can alter this adaptation. Here, we review the latest advances in plant functional traits research and on species strategies to the main environmental factors occurring in grassland ecosystems: nutrient availability, grazing, cutting and shading. Functional ecology also provides a framework to better understand how species strategies interact with the species composition at the community level. Therefore, the literature on community assembling theories in relation to ecosystem processes most relevant to grassland management and services is also reviewed. Finally, future research questions and some new orientations for grassland experts are offered in order to meet the challenge of maintaining productivity and preservation of these semi-natural environments in the face of global change. © 2015, INRA and Springer-Verlag France. Source

Eiras C.E.,Federal University of Reconcavo da Bahia | Marques J.D.A.,Federal University of Reconcavo da Bahia | Prado R.M.D.,State University of Maringa | Valero M.V.,State University of Maringa | And 4 more authors.
Meat Science | Year: 2014

The effects of corn replacement by different glycerine levels on carcass characteristics and meat quality of 40 young Purunã bulls, weighing 209. ±. 33.3. kg and 8. ±. 0.9. months old, finished in feedlot, were evaluated. The treatments were G00: without glycerine; G06: 6% glycerine; G12: 12% glycerine; and G18: 18% glycerine in the diets, on a DM basis. Hot weight, dressing, conformation and length carcass, leg length and cushion thickness were not (P> 0.05) modified by different glycerine levels in the diets. Glycerine in the diets did not (P> 0.05) affect fat thickness, Longissimus muscle area, marbling and texture. Muscle, fat and bone percentages were not (P> 0.05) influenced by glycerine levels in the diets. No changes (P> 0.05) in lightness (L*), redness (a*) and yellowness (b*) on LM occurred when glycerine was included at 0, 6, 12 or 18% in the diet. There was no (P> 0.05) difference in LM moisture, ash, crude protein and total lipids when feeding different glycerine levels. The inclusion of glycerine decreased (. P<. 0.01) total saturated (10.8%), and increased monounsaturated (7.4%) and poly-unsaturated (44.0%) fatty acids, which resulted in a higher PUFA:SFA ratio (0.57). © 2013 Elsevier Ltd. Source

Eiras C.E.,State University of Maringa | Barbosa L.P.,Federal University of Reconcavo da Bahia | Marques J.A.,Federal University of Reconcavo da Bahia | Araujo F.L.,Federal University of Reconcavo da Bahia | And 4 more authors.
Animal Feed Science and Technology | Year: 2014

This work was carried out to study different levels of glycerine as a partial replacement of corn on apparent digestibility, feed intake and efficiency and animal performance in young Purunã bulls finished in a feedlot. This study used 40 Purunã bulls of 209 ± 33.3. kg live weight and 8 ± 0.9 months old at the start of the experiment. The bulls were kept in a feedlot for 240 days. The diets were as follows: no glycerine and glycerine added at 60, 120 and 178. g/kg DM. The apparent digestibility of nutrients increased with increasing glycerine in the diet, with the exception of ether extract and neutral detergent fibre. Feed efficiency was improved by increasing glycerine level in the diet. The feed intake and animal performance were similar among the four diets. © 2014 Elsevier B.V. Source

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