RESUMEN
Data gaps and biases are two important issues that affect the quality of biodiversity information and downstream results. Understanding how best to fill existing gaps and account for biases is necessary to improve our current information most effectively. Two current main approaches for obtaining and improving data include (1) curation of biological collections, and (2) fieldwork. However, the comparative effectiveness of these approaches in improving biodiversity data remains little explored. We used the Flora de Bogotá project to study the magnitude of change in species richness, spatial coverage, and sample coverage of plant records based on curation versus fieldwork. The process of curation resulted in a decrease in species richness (synonym and error removal), but it significantly increased the number of records per species. Fieldwork contributed to a slight increase in species richness, via accumulation of new records. Additionally, curation led to increases in spatial coverage, species observed by locality, the number of plant records by species, and localities by species compared to fieldwork. Overall, curation was more efficient in producing new information compared to fieldwork, mainly because of the large number of records available in herbaria. We recommend intensive curatorial work as the first step in increasing biodiversity data quality and quantity, to identify bias and gaps at the regional scale that can then be targeted with fieldwork. The stepwise strategy would enable fieldwork to be planned more cost-effectively given the limited resources for biodiversity exploration and characterization.
RESUMEN
Recent debates on the number of plant species in the vast lowland rain forests of the Amazon have been based largely on model estimates, neglecting published checklists based on verified voucher data. Here we collate taxonomically verified checklists to present a list of seed plant species from lowland Amazon rain forests. Our list comprises 14,003 species, of which 6,727 are trees. These figures are similar to estimates derived from nonparametric ecological models, but they contrast strongly with predictions of much higher tree diversity derived from parametric models. Based on the known proportion of tree species in neotropical lowland rain forest communities as measured in complete plot censuses, and on overall estimates of seed plant diversity in Brazil and in the neotropics in general, it is more likely that tree diversity in the Amazon is closer to the lower estimates derived from nonparametric models. Much remains unknown about Amazonian plant diversity, but this taxonomically verified dataset provides a valid starting point for macroecological and evolutionary studies aimed at understanding the origin, evolution, and ecology of the exceptional biodiversity of Amazonian forests.
Asunto(s)
Biodiversidad , Bases de Datos Factuales , Plantas/clasificación , Bosque Lluvioso , BrasilRESUMEN
This paper presents a spatial and temporal analysis of child pedestrian crash data in Santiago, Chile during the period 2000-2008. First, this study identified seven critical areas with high child pedestrian crash risk employing kernel density estimation, and subsequently, statistically significant clusters of the main attributes associated to these crashes in each critical area were determined in a geographic information systems environment. Moran's I index test identified a positive spatial autocorrelation on crash contributing factors, time of day, straight road sections and intersections, and roads without traffic signs within the critical areas during the studied period, whereas a random spatial pattern was identified for crashes related to the age attribute. No statistical significance in the spatial relationship was obtained in child pedestrian crashes with respect to gender, weekday, and month of the year. The results from this research aid in determining the areas in which enhanced school-age child pedestrian safety is required by developing and implementing effective enforcement, educational, and engineering preventive measures.