Abstract
BackgroundCentral 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.Results1) 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.ConclusionsOur 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.
Highlights
Before human intervention, the nation of Panama was most forest, and forest ecosystems in the moist tropics are diverse
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
What fraction of tropical trees are highly endemic, having ranges < 20, 000 km2? At the other extreme, how widely do the broadest ranges extend? Do range sizes vary taxonomically, i.e. do some families have more narrow endemics than others, and do ranges vary with the height of a tree species? We report how many tree species in Panama have never been censused in plots
Summary
The nation of Panama was most forest, and forest ecosystems in the moist tropics are diverse. The southern end of Central America, morever, falls within a region where plant species richness reaches a global maximum (Barthlott et al 1996). Because conserving forest ecosystems requires an understanding of their component species, we set out to catalog the tree species of Panama and document their geographic ranges. Even to assemble a list of known species, is challenging because botanical knowledge across the Neotropics lags well behind North America, Europe, We have been studying trees of Panama for 35 years at intensively surveyed research sites using fully censused plots (Hubbell and Foster 1986a; Condit 1998a; Condit et al 2004; Condit et al 2005; Condit et al 2011; Condit et al 2017). 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
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