Search

RESUMEN: Los páramos son ecosistemas andinos de alta montaña, que albergan una biota diversa y de alta endemicidad, producto de las condiciones ambientales extremas. Se utilizaron diferentes índices para definir prioridades de conservación en las áreas de páramo del departamento de Antioquia, Colombia; con base en medidas de la individualidad evolutiva y complementariedad de biotas. Para realizar los análisis se generó una base de datos que incluyó 416 táxones de angiospermas y 1 951 localidades, para un total de 12 897 registros de distribución, compilados a partir de los muestreos y revisiones realizados en este proyecto; adicionalmente se incluyó la información disponible en Global Biodiversity Information Facility y en el Sistema de Información sobre Biodiversidad de Colombia. A partir de estos datos se identificaron áreas de prioridad para la conservación de los páramos de Antioquia, de acuerdo con medidas de la individualidad evolutiva basadas en nodos y complementariedad de biotas. Teniendo en cuenta solamente los índices de individualidad evolutiva, el páramo prioritario para la conservación fue Frontino-Urrao, seguido de Farallones de Citará; pero si se considera la complementariedad de biotas, la segunda área prioritaria para la conservación es Sonsón. Las clasificaciones de prioridad de áreas basadas en individualidad son congruentes con las áreas de mayor riqueza de especies. Es necesario y urgente preservar el ecosistema páramo dado su vulnerabilidad y la subsecuente perdida de los servicios ecosistémicos que brindan, si se ven expuestos a la degradación o desaparición. ABSTRACT: Páramos are High Andean ecosystems that harbor a diverse biota and have high endemicity, because of their extreme environmental conditions. We used different phylogenetic indices to define conservation priorities in the paramos of the department of Antioquia, Colombia, based on measures of their evolutionary individuality and richness complimentary. To perform the analyses, we generated a database including 416 angiosperm taxa and 1951 localities for a total of 12 897 distributional records compiled from surveys and reviews. Additionally, the available information in the Global Biodiversity Information Facility and the Colombian Biodiversity Information System were included. From these data, priority areas for the conservation of the paramos located in the state of Antioquia were identified, using measures of evolutionary individuality based on nodes and biotic complementarity. Taking into account only the individual phylogenetic indices, the most important paramo for conservation was Frontino-Urrao, followed by Farallones de Citará. If biotic complementarity is considered, the second most important paramo is Sonsón. Priority classifications of areas based on individuality are congruent with areas of greatest species richness. We conclude that it is necessary and urgent to preserve the paramos given their vulnerability and the subsequent loss of the ecosystem services that they provide, if they are exposed to degradation or disappearance. COL0008227

The composition of ecological assemblages depends on a variety of factors including environmental filtering, biotic interactions and dispersal limitation. By evaluating the phylogenetic pattern of assemblages, we gain insight into the relative contribution of these mechanisms to generating observed assemblages. We address some limitations in the field of community phylogenetics by using simulations, biologically relevant null models, and cost distance analysis to evaluate simultaneous mechanisms leading to observed patterns of cooccurrence. Building from past studies of phylogenetic community structure, we applied our approach to hummingbird assemblages in the Northern Andes. We compared the relationship between relatedness and co-occurrence among predicted assemblages, based on estimates of suitable habitat and dispersal limitation, and observed assemblages. Hummingbird co-occurrence peaked at intermediate relatedness and decreased when a closely-related species was present. This result was most similar to simulations that included simultaneous effects of phylogenetic conservatism and repulsion. In addition, we found older sister taxa were only weakly more separated by geographic barriers, suggesting that time since dispersal is unlikely to be the sole factor influencing co-occurrence of closely related species. Our analysis highlights the role of multiple mechanisms acting simultaneously, and provides a hypothesis for the potential importance of competition at regional scales. COL0147267

Patterns of phylogenetic structure of assemblages are increasingly used to gain insight into the ecological and evolutionary processes involved in the assembly of co-occurring species. Metrics of phylogenetic structure can be sensitive to scaling issues and data availability. Here we empirically assess the sensitivity of four metrics of phylogenetic structure of assemblages to changes in (i) the source of data, (ii) the spatial grain at which assemblages are defined, and (iii) the definition of species pools using hummingbird (Trochilidae) assemblages along an elevational gradient in Colombia. We also discuss some of the implications in terms of the potential mechanisms driving these patterns. To explore how source of data influence phylogenetic structure we defined assemblages using three sources of data: field inventories, museum specimens, and range maps. Assemblages were defined at two spatial grains: coarse-grained (elevational bands of 800-m width) and fine-grained (1-km2 plots). We used three different species pools: all species contained in assemblages, all species within half-degree quadrats, and all species either above or below 2000 m elevation. Metrics considering phylogenetic relationships among all species within assemblages showed phylogenetic clustering at high elevations and phylogenetic evenness in the lowlands, whereas those metrics considering only the closest co-occurring relatives showed the opposite trend. This result suggests that using multiple metrics of phylogenetic structure should provide greater insight into the mechanisms shaping assemblage structure. The source and spatial grain of data had important influences on estimates of both richness and phylogenetic structure. Metrics considering the co-occurrence of close relatives were particularly sensitive to changes in the spatial grain. Assemblages based on range maps included more species and showed less phylogenetic structure than assemblages based on museum or field inventories. Coarse-grained assemblages included more distantly related species and thus showed a more even phylogenetic structure than fine-grained assemblages. Our results emphasize the importance of carefully selecting the scale, source of data and metric used in analysis of the phylogenetic structure of assemblages. COL0147267