Estimating bioregions and undercollected areas in South America by revisiting Byttnerioideae, Helicteroideae and Sterculioideae (Malvaceae) occurrence data

Abstract

Revisiting biogeographical patterns is the first step towards fully assessing the natural history and conservation of particular lineages, an important effort in species-rich groups from heterogeneous or undercollected areas, such as South American Malvaceae. Here, we compile, synthetize and discuss a manually revisited distribution database built for species of three subfamilies of Malvaceae—Byttnerioideae, Helicteroideae and Sterculioideae—from South America. Our database was assembled from vouchers publicly available in online repositories and from an extensive literature survey. We retrieved 14,528 records of 271 species in 11 genera, 231 (85%) endemic to South America. Different species are indicative of different bioregions, collection efforts for the groups are heterogeneous within South America, and the Amazon region is the area with highest levels of biasing effects. Occurrence records are widespread throughout South America, and most species are centered in open seasonally dry formations, especially in the Brazilian Cerrado, Caatinga and the Chaco. Furthermore, we found secondary centers of species richness in the Northwestern region of South America, in the Andean portions of Colombia, Ecuador and Peru, as well as in the Southern portion of the Brazilian Atlantic Forest. The Amazon region—the most undercollected area of South America for the groups—also shows some remarkable records, namely from arborescent genera of Byttnerioideae (Theobroma and Herrania) and species of Sterculioideae. Occurrence maps of species richness, a full list of revisited records and a summary of records per species were presented and discussed considering known biogeographical patterns for plants in the Neotropical region.