Structural response of Caribbean dry forests to hurricane winds: a case study from Guanica Forest, Puerto Rico

Tropical dry forests in the Caribbean have an uniquely short, shrubby structure with a high proportion of multiple-stemmed trees compared to dry forests elsewhere in the Neotropics. Previous studies have shown that this structure can arise without the loss of main stems from cutting, grazing, or other human intervention. The Caribbean has a high frequency of hurricanes, so wind may also influence forest stature. Furthermore, these forests also tend to grow on soils with low amounts of available phosphorus, which may also influence structure. The objective of this study was to assess the role of high winds in structuring dry forest, and to determine whether soil nutrient pools influence forest response following hurricane disturbance. Methods: Over 2000 stems in five plots were sampled for hurricane effects within 1 week after Hurricane Georges impacted field sites in 1998. Sprout initiation, growth, and mortality were analysed for 1407 stems for 2 years after the hurricane. Soil nutrient pools were measured at the base of 456 stems to assess association between nutrients and sprout dynamics. Results: Direct effects of the hurricane were minimal, with stem mortality at \u3c 2% and structural damage to stems at 13%, although damage was biased toward stems of larger diameter. Sprouting response was high . over 10 times as many trees had sprouts after the hurricane as before. The number of sprouts on a stem also increased significantly. Sprouting was common on stems that only suffered defoliation or had no visible effects from the hurricane. Sprout survival after 2 years was also high (\u3e 86%). Soil nutrient pools had little effect on forest response as a whole, but phosphorus supply did influence sprout dynamics on four of the more common tree species. Main Conclusions: Hurricanes are able to influence Caribbean tropical dry forest structure by reducing average stem diameter and basal area and generating significant sprouting responses. New sprouts, with ongoing survival, will maintain the high frequency of multi-stemmed trees found in this region. Sprouting is not limited to damaged stems, indicating that trees are responding to other aspects of high winds, such as short-term gravitational displacement or sway. Soil nutrients play a secondary role in sprouting dynamics of a subset of species. The short, shrubby forest structure common to the Caribbean can arise naturally as a response to hurricane winds

Ecological informatics: An introduction

Friedrich Recknagel and William K. Michene

Conceptual Model Enhancing Accessibility of Data from Cancer–Related Environmental Risk Assessment Studies

Part 5: Information Tools for Global Environmental AssessmentInternational audienceThis paper proposes conceptual model which can be used to facilitate the discovery, integration and analysis of environmental data in cancer-related risk studies. Persistent organic pollutants were chosen as a model because of their persistence, bioaccumulation potential and genotoxicity. Part dealing with cancer risk is primarily focused on population-based observations encompassing a wide range of epidemiologic studies, from local investigations to national cancer registries. The proposed model adopted multilayer hierarchy working with characteristics of given entities (POPs, cancer diseases as nomenclature classes) and couples “observation – measurement” as content defining classes. The proposal extends formally used taxonomy applying multidimensional set of descriptors including scores of measurement validity and precision. This solution has the potential to aid multidisciplinary data discovery and knowledge mining. The same structure of descriptors used for environmental and cancer part enables the users to integrate different data sources recognizing their methodical origin, time & space coordinates and validity