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.

Islands with large colonies of seabirds are found throughout the globe. Seabird islands provide nesting and roosting sites for birds that forage at sea, deposit marine nutrients on land, and physically alter these islands. Habitats for numerous endemic and endangered animal and plant species, seabird islands are therefore biodiversity hotspots with high priority for conservation. Successful campaigns to eradicate predators (e.g., rats and cats) from seabird islands have been conducted worldwide. However, removal of predators will not necessarily lead to natural recovery of seabirds or other native species. Restoration of island ecosystems requires social acceptance of eradications, knowledge of how island food webs function, and a long-term commitment to measuring and assisting the recovery process. This book, written collaboratively by and for ecologists and resource managers, provides the first large-scale cross-system compilation, comparison, and synthesis of the ecology of seabird island systems. Offering a new conceptual framework into which to fit the impacts of seabirds on island ecology, this is an essential resource for academics and resource managers alike.