The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼ 40,000 and ∼ 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼ 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼ 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.

No abstract

The Earth is undergoing an accelerated rate of native ecosystem conversion and degradation and there is increased interest in measuring and modelling biodiversity from space. Biogeographers have a long-standing interest in measuring patterns of species occurrence and distributional movements and an interest in modelling species distributions and patterns of diversity. Much progress has been made in identifying plant species from space using high-resolution satellites (QuickBird, IKONOS), while the measurement of species movements has become commonplace with the ARGOS satellite tracking system which has been used to track the movements of thousands of individual animals. There have been significant advances in land-cover classifications by combining data from multi-passive and active sensors, and new classification techniques. Species distribution modelling has been growing at a striking rate and the incorporation of spaceborne data on climate, topography, land cover, and vegetation structure has great potential to improve models. There have been significant advances in modelling species richness, alpha diversity, and beta diversity using multisensors to quantify land-cover classifications and landscape metrics, measures of productivity, and measures of heterogeneity. Remote sensing of nature reserves can provide natural resources managers with near real-time data within and around reserves that can be used to support conservation efforts anywhere in the world. Future research should focus on incorporating recent spaceborne sensors, more extensive integration of available spaceborne imagery, and the collection and dissemination of high-quality field data. This will improve our understanding of the distribution of life on earth.

Tropical dry forests are one of the world's most endangered forest types. Currently there are no comparative data on extent or levels of species richness for remaining forest fragments. This research identifies landscape metrics and spectral indices that can be applied at the stand and patch level to predict woody‐plant species richness in tropical dry forests. This study was undertaken in 18 stands of tropical dry forest with nine sites in the Florida Keys and nine sites within an urban–agricultural matrix in mainland Florida, USA. Woody‐plant species richness was quantified at the stand level (belt transects totaling 500 m2) and patch level (presence/absence data for 65 native tropical plants ≤2.5 cm dbh) for all study sites. Landsat Enhanced Thematic Mapper Plus (ETM+) satellite images (pixel resolution 30 × 30 m) were used to assess the utility of landscape metrics (forest patch area, nearest neighbor distance, shape index, boundary complexity) and spectral indices (normalized‐difference vegetation index [NDVI] for nine pixels and 500 pixels directly over transects, and all pixels in the forest patch area) for predicting stand‐ and patch‐level species richness. The 18 stands of tropical dry forest sampled in this study included 4248 woody plants, representing 71 species. Islands in the Florida Keys had higher levels of woody‐plant species richness than mainland sites. There was a significant positive relationship between mean NDVI for the nine pixels over each stand and stand species richness and a significant negative relationship between species richness and standard deviation of NDVI for nine pixels over each stand. The density of evergreen plants explained 66% of the variability in mean NDVI. At the patch level, forest patch area and mean NDVI at the stand, 500‐pixel, and patch level were all positively associated with patch species richness. However, combining forest patch area with NDVI significantly improved the prediction of patch species richness. Results from this study support the species–energy theory at the level of a forest stand and patch and suggest that a first‐order approximation of woody‐plant species richness in stands and patches of tropical dry forest is possible in biodiversity hot spots.

 RESEARCH AND PRACTICE  Objectives. We assessed the levels and correlates of posttraumatic stress reactivity (PTSR) of more than 20 000 adult tsunami survivors by analyzing survey data from coastal Aceh and North Sumatra, Indonesia.Methods. A population-representative sample of individuals interviewed before the tsunami was traced in 2005 to 2006. We constructed 2 scales measuring PTSR by using 7 symptom items from the Post Traumatic Stress Disorder (PTSD) Checklist-Civilian Version. One scale measured PTSR at the time of interview, and the other measured PTSR at the point of maximum intensity since the disaster.Results. PTSR scores were highest for respondents from heavily damaged areas. In all areas, scores declined over time. Gender and age were significant predictors of PTSR; markers of socioeconomic status before the tsunami were not. Exposure to traumatic events, loss of kin, and property damage were significantly associated with higher PTSR scores.Conclusions. The tsunami produced posttraumatic stress reactions across a wide region of Aceh and North Sumatra. Public health will be enhanced by the provision of counseling services that reach not only people directly affected by the tsunami but also those living beyond the area of immediate impact. (Am J Public Health.