Nitrogen fixation ability explains leaf chemistry and arbuscular mycorrhizal responses to fertilization

Atmospheric nitrogen (N) and phosphorus (P) deposition rates are predicted to drastically increase in the coming decades. The ecosystem level consequences of these increases will depend on how plant tissue nutrient concentrations, stoichiometry and investment in nutrient uptake mechanisms such as arbuscular mycorrhizal fungi (AMF) change in response to increased nutrient availability, and how responses differ between plant functional types. Using a factorial nutrient addition experiment with seedlings of multiple N-fixing and non-N-fixing tree species, we examined whether leaf chemistry and AMF responses differ between these dominant woody plant functional groups of tropical savanna and dry forest ecosystems. We found that N-fixers have remarkably stable foliar chemistry that stays constant with external input of nutrients. Non-N-fixers responded to N and N + P addition by increasing both concentrations and total amounts of foliar N, but showed a corresponding decrease in P concentrations while total amounts of foliar P stayed constant, suggesting a ‘dilution’ of tissue P with increased N availability. Non-N-fixers also showed an increase in N:P ratios with N and N + P addition, probably driven by both an increase in N and a decrease in P concentrations. AMF colonization decreased with N + P addition in non-N-fixers and increased with N and N + P addition in N-fixers, suggesting differences in their nutrient acquisition roles in the two plant functional groups. Our results suggest that N-fixers and non-N-fixers can differ significantly in their responses to N and P deposition, with potential consequences for future nutrient and carbon cycling in savanna and dry forest ecosystems

Pollinator networks, alien species and the conservation of rare plants: Trinia glauca as a case study

1. Despite the essential role of pollination in the maintenance of many rare plant species, conservation management plans rarely consider the service of pollination. 2. This study identifies the main pollinators of a rare English plant species, Trinia glauca (Apiaceae), and provides recommendations for its conservation. A community-level approach is used, whereby a visitation network is constructed to identify the direct and indirect links between T. glauca and other members of the plant-visitor community. 3. A field experiment that excluded the main visitor species from female T. glauca showed that ants were the main pollinators of T. glauca . The network revealed that over the field season, 33% of the ants’ visits to flowers were to alien plants, with Cotoneaster horizontalis making a particularly high contribution (58%) during the T. glauca flowering period. 4. The removal of alien plants is a part of the conservation management of T. glauca , and we simulated the likely consequences of this form of habitat management on T. glauca pollination, any effects being mediated by shared pollinators. Although positive or neutral effects are possible, a negative effect is also possible, whereby the removal of alien plants leads to a crash in ant populations, potentially reducing pollinator visits to T. glauca by up to 85·2%. 5. Synthesis and applications . Conserving the pollinators of rare plants is essential if their conservation is to be sustainable in the long term. Our data indicate that T. glauca is pollinated by ants and demonstrate that ants can also feed on alien plants, particularly during the flowering season of this rare plant. We suggest that management measures involving the removal of alien plants should consider the possible negative impacts on rare plants through changes in pollinator populations. In this case, a staged removal is likely to prove the best conservation approach, allowing the pollinators’ response to be assessed before any serious negative effects occur

Experiência existencial de mães de crianças hospitalizadas em Unidade de Terapia Intensiva Pediátrica Experiencia existencial de madres de niños hospitalizados en Unidades de Terapia Intensiva Pediátrica Existetial experienc of mothers of hospitalized children in intensive pediatric care unit

Este estudo tem como objetivo compreender a experiência existencial de mães de crianças hospitalizadas em Unidade de Terapia Intensiva Pediátrica (UTIP). Trata-se de uma pesquisa de natureza qualitativa, consubstanciada na Teoria Humanística de Enfermagem. O cenário da investigação foi uma UTIP de um hospital público. Participaram do trabalho cinco mães de crianças hospitalizadas na referida unidade. Os dados foram analisados com base nas cinco fases da Enfermagem Fenomenológica. A partir dos discursos expressos durante a coleta de dados, emergiram as seguintes temáticas: a relação vivenciada entre as mães e os profissionais de enfermagem no momento da admissão e ao longo da hospitalização da criança na UTIP; e mães vivenciando sentimentos de medo, desespero e solidão diante do adoecimento do filho. O presente estudo ressalta a complexidade de que se reveste uma abordagem centrada nas genitoras e subsidia um novo olhar no âmbito da assistência, do ensino e da pesquisa em enfermagem.<br>Este estudio tiene como objetivo comprender la experiencia existencial de madres de niños hospitalizados en Unidades de Terapia Intensiva Pediátrica (UTIP). Se trata de una investigación de naturaleza cualitativa basada en la Teoría Humanística de Enfermería. El escenario de la investigación fue una UTIP de un hospital público. Participaron del trabajo cinco madres de niños hospitalizados en la referida unidad. Los datos fueron analizados con base en las cinco fases de la Enfermería Fenomenológica. A partir de los discursos expresados durante la recolección de datos emergieron las siguientes temáticas: la relación experimentada entre las madres y los profesionales de enfermería en el momento de la admisión y a lo largo de la hospitalización del niño en la UTIP; madres experimentando sentimientos de miedo, desesperación y soledad delante de la enfermedad del hijo. El presente estudio resalta la complejidad de que se reviste un abordaje centrado en las genitoras y muestra una nueva perspectiva en el ámbito de la asistencia, de la enseñanza y de la investigación en enfermería.<br>This study has the objective of understanding the existential experience of mothers of children hospitalized in an Intensive Pediatric Care Unit (IPCU). It is a qualitative-based research grounded on the humanistic nursing theory. The investigation scenario was the IPCU of a public hospital. Five mothers of children who were hospitalized in the referred unit participated in the investigation. Data were analyzed from the standpoint of the five phases of the phenomenological nursing. The following issues emerged from the collected statements: the relationship between mothers and nursing professionals at the moment of admission and throughout the child's hospitalization period in the IPCU; and mothers who experience fear, despair and loneliness in face of the child's disease. The present study highlights the complexity of a mother-centered approach and subsidizes a new look at the field of the care, teaching and nursing research