RESUMO
Treelines are sensitive to environmental changes, but few studies provide a mechanistic approach to understand treeline dynamics based on field experiments. The aim of this study was to determine how changes in the abiotic and/or biotic conditions associated with global change affect the performance of tree seedlings (later saplings) at the treeline in a 10-year experiment. A fully factorial experiment in the Central Pyrenees was initiated in autumn 2006; 192 Pinus uncinata seedlings were transplanted into microplots with contrasting environmental conditions of (1) increased vs. ambient temperature, (2) increased nutrient availability vs. no increase, and (3) presence vs. absence of the dominant shrub Rhododendron ferrugineum. We assessed the performance of young pines on several occasions over 10 years. The pines were removed at the end of the experiment in autumn 2016 to characterize their morphology and to conduct chemical and isotopic analyses on their needles. Both the warming and the fertilization treatments increased seedling growth soon after the start of the experiment. R. ferrugineum facilitated the survival and development of pine seedlings during the early years and affected the chemical composition of the needles. Toward the end of the experiment, the transplanted P. uncinata individuals, by then saplings, competed with R. ferrugineum for light and nutrients; the presence of the shrub probably altered the strategy of P. uncinata for acquiring nutrients and buffered the effects of warming and fertilization. The pines were highly sensitive to all factors and their interactions throughout the entire experimental period. These findings indicated that the interactive effects of several key abiotic and biotic drivers associated with global change should be investigated simultaneously for understanding the contribution of young trees to treeline dynamics.
RESUMO
Los tumores mesenquimáticos de la mucosa uterina son un grupo raro, heterogéneo y generalmente agresivo de neoplasias que conduce frecuentemente a una diseminación y muerte temprana. Constituyen menos del 3% de todos los tumores malignos del Tracto Genital Femenino y el 2-7% de las neoplasias malignas uterinas. Presentamos 4 casos de tumores mesenquimáticos diagnosticados en un período de 5 años en el Servicio de Anatomía Patológica del Hospital General de Agudos Carlos G. Durand, analizando su incidencia y haciendo una breve revisión de las características histopatológicas de los mismos
Mesenchymal tumors of the uterine lining are a rare and heterogeneous group of neoplasms, with an agressive behavior leading to an early dissemination and death. They represent less than 3% of all malignant tumors of the Female Genital Tract and 2-7% of uterine malignancies. We report 4 mesenchymal tumors diagnosed throughout a 5 years period at the Department of Pathology Hospital General Carlos G. Durand, analyzing their incidence and making a review of the histopathologic features
