Trees of Panama: A complete checklist with every geographic range

Abstract

Background: Central America is one of the most diverse floristic provinces in the world, but comprehensive plant lists for the region are incomplete and need frequent updating. Full geographic ranges of individual species are seldom known. Our detailed forest inventory plots of Panama thus lack a global geographic perspective. In order to provide one, we assembled a thoroughly vetted checklist of all tree species of Panama, along with an estimate of each one’s range size based on published specimen records. Results: 1) Panama has 3043 tree species in 141 families and 752 genera; 57.6% were ≥ 10 m tall and 16.9% were 3-5 m tall.2) The widest ranges were >1.5×107 km2, covering the entire neotropics and reaching >30∘ latitude; 12.4% of the species had ranges exceeding 107 km2. The median range was 6.9×105 km2.3) At the other extreme, 16.2% of the species had a range <20,000 km2, a criterion suggesting endangered status.4) Range size increased with a tree species’ height and varied significantly among families.5) Tree census plots, where we mapped and measured all individuals, captured 27.5% of the tree species, but a biased selection relative to range size; only 4.5% of the species in plots had ranges <20,000 km2. Conclusions: Our checklist of the trees of Panama, based on rigorous criteria aimed at matching plot censuses, is 20% larger than previous. By recording species’ maximum heights, we allow comparisons with other regions based on matching definitions, and the range sizes provide a quantitative basis for assessing extinction risk. Our next goal is to merge population density from plot censuses to add rigor to predictions of extinction risk of poorly-studied tropical tree species.