ABSTRACT
Climate change, with warming and drying weather conditions, is reducing the growth, seed production, and survival of fire-adapted plants in fire-prone regions such as Mediterranean-type ecosystems. These effects of climate change on local plant demographics have recently been shown to reduce the persistence time of local populations of the fire-killed shrub Banksia hookeriana dramatically. In principle, extinctions of local populations may be partly compensated by recolonization events through long-distance dispersal mechanisms of seeds, such as post-fire wind and bird-mediated dispersal, facilitating persistence in spatially structured metapopulations. However, to what degree and under which assumptions metapopulation dynamics might compensate for the drastically increased local extinction risk remains to be explored. Given the long timespans involved and the complexity of interwoven local and regional processes, mechanistic, process-based models are one of the most suitable approaches to systematically explore the potential role of metapopulation dynamics and its underlying ecological assumptions for fire-prone ecosystems. Here we extend a recent mechanistic, process-based, spatially implicit population model for the well-studied fire-killed and serotinous shrub species B. hookeriana to a spatially explicit metapopulation model. We systematically tested the effects of different ecological processes and assumptions on metapopulation dynamics under past (1988-2002) and current (2003-2017) climatic conditions, including (i) effects of different spatio-temporal fires, (ii) effects of (likely) reduced intraspecific plant competition under current conditions and (iii) effects of variation in plant performance among and within patches. In general, metapopulation dynamics had the potential to increase the overall regional persistence of B. hookeriana. However, increased population persistence only occurred under specific optimistic assumptions. In both climate scenarios, the highest persistence occurred with larger fires and intermediate to long inter-fire intervals. The assumption of lower intraspecific plant competition caused by lower densities under current conditions alone was not sufficient to increase persistence significantly. To achieve long-term persistence (defined as >400 years) it was necessary to additionally consider empirically observed variation in plant performance among and within patches, that is, improved habitat quality in some large habitat patches (≥7) that could function as source patches and a higher survival rate and seed production for a subset of plants, specifically the top 25% of flower producers based on current climate conditions monitoring data. Our model results demonstrate that the impacts of ongoing climate change on plant demographics are so severe that even under optimistic assumptions, the existing metapopulation dynamics shift to an unstable source-sink dynamic state. Based on our findings, we recommend increased research efforts to understand the consequences of intraspecific trait variation on plant demographics, emphasizing the variation of individual traits both among and within populations. From a conservation perspective, we encourage fire and land managers to revise their prescribed fire plans, which are typically short interval, small fires, as they conflict with the ecologically appropriate spatio-temporal fire regime for B. hookeriana, and likely as well for many other fire-killed species.
ABSTRACT
Resumen: Introducción: la morbimortalidad permite evaluar la calidad asistencial, outcome y comparar diferentes centros asistenciales. Éste es el primer estudio de morbimortalidad en neurocirugía realizado en Uruguay. Objetivo: determinar la morbimortalidad global y específica en el Departamento de Neurocirugía del Hospital de Clínicas y la asociación entre complicación y morbimortalidad. Metodología: estudio observacional, descriptivo-analítico, longitudinal, retrospectivo de todos los pacientes >15 años que requirieron cirugía entre abril de 2017 y abril de 2019. Los datos se obtuvieron de historias clínicas y se analizaron las siguientes variables: edad, sexo, comorbilidad, clínica, diagnóstico, oportunidad quirúrgica, complicación, tipo de complicación, mortalidad, causa de mortalidad, outcome y tiempo quirúrgico. Resultados: 477 pacientes fueron intervenidos, 72 complicados. La mortalidad global fue 5,5% (26/477) y la morbilidad 15% (72/477). 36% de los pacientes complicados fallecieron (26/72). La patología vascular fue la morbilidad específica que más se complicó (20%, 14/69). La infección fue el tipo de complicación más frecuente (46%, 39/84). La propia evolución de la enfermedad y el terreno causó la muerte del 90% de los pacientes complicados operados de urgencia (19/21), siendo ésta última factor de riesgo independiente de fallecer (p=0,018). En coordinaciones, la causa de muerte estuvo vinculada al acto quirúrgico (80%). Hubo asociación entre patología vascular y morbimortalidad (p=0,015) y entre complicación isquémica y morbimortalidad (p=0,024). La presencia de hipertensión endocraneana (HEC) se asoció a un mal resultado (p=0,003). Conclusiones: los resultados muestran una buena calidad de atención comparado con otros centros. Aún existen aspectos a corregir para reducir la morbimortalidad.
Abstract: Introduction: morbidity and mortality rates allow for the evaluation of the quality of care and outcome and they also make it possible to compare different healthcare centers. This is the first morbidity and mortality study in neurosurgery carried out in Uruguay. Objective: to determine the global and specific morbidity and mortality rates in the Neurosurgery Department at the Clínicas University Hospital, and to determine if mortality and morbidity are associated to surgical complications. Method: retrospective, longitudinal, observational and descriptive analysis of all patients >15 years old that underwent a neurosurgical procedure between April 2017 and 2019. Data were obtained from patient medical records. The following variables were analyzed: age, sex, comorbidity, clinical data, diagnosis, opportunity of surgical procedure, complications, type of complication, mortality, cause of mortality, outcome and surgical time. Results: 477 patients underwent neurosurgical procedure, 72 of which were complicated surgeries. Overall mortality was 5.5% (26/477) and morbidity 15% (72/477). 36% of complicated patients died (26/72). Vascular pathology was the specific morbidity that complicated patients the most 20% (14/69). Infection was the most frequent type of complication 46% (39/84). The evolution of the disease itself and the terrain caused the death of 90% of complicated patients undergoing emergency surgery (19/21), being the latter an independent risk factor for death (p = 0.018). As to coordinated surgeries, the cause of death was associated to the surgical act (80%). Association was found between vascular pathology and morbidity and mortality (p = 0.015) and between ischemic complication and morbidity and mortality (p = 0.024). The presence of intracranial hypertension (IH) was associated with a bad outcome (p= 0.003). Conclusions: the results show a good quality of care compared to other centers. There are still aspects to correct to reduce morbidity and mortality rates.
Resumo: Introdução: a análise da morbimortalidade permite avaliar a qualidade do atendimento e dos resultados e comparar diferentes centros de saúde. Este é o primeiro estudo de morbimortalidade em neurocirurgia realizado no Uruguai. Objetivo: determinar a morbimortalidade global e específica no Departamento de Neurocirurgia do Hospital de Clínicas e a associação entre complicação e morbimortalidade. Metodologia: estudo observacional, descritivo-analítico, longitudinal, retrospectivo de todos os pacientes >15 anos que necessitaram de cirurgia entre abril de 2017 e 2019. Os dados foram obtidos dos prontuários dos pacientes e as variáveis analisadas foram: idade, sexo, comorbidade, aspectos clínicos, diagnóstico, oportunidade cirúrgica, complicação, tipo de complicação, mortalidade, causa da mortalidade, resultado e tempo cirúrgico. Resultados: 477 pacientes foram operados dos quais 72 apresentaram complicações. A mortalidade geral foi de 5,5% (26/477) e a morbidade de 15% (72/477). 36% dos pacientes com complicações morreram (26/72). A patologia vascular foi a causa específica de mortalidademorbidade específica mais freqüente 20% (14/69). A infecção foi o tipo de complicação mais freqüente 46% (39/84). A evolução da própria doença e do local da cirurgia ocasionou a morte de 90% dos pacientes com complicações submetidas a cirurgias de urgência (19/21), sendo este último fator de risco independente para óbito (p = 0,018). Nas cirurgias eletivas, a causa da morte esteve ligada ao ato cirúrgico (80%). Houve associação entre patologia vascular e morbimortalidade (p = 0,015) e entre complicação isquêmica e morbimortalidade (p = 0,024). A presença de hipertensão intracraniana (HEC) foi associada a um desfecho ruim (p = 0,003). Conclusões: os resultados mostram uma boa qualidade de atendimento em comparação com outros centros. Ainda há aspectos a serem corrigidos para reduzir a morbimortalidade.
