How many bromeliads are there?

Abstract

- In many taxa the expected number of species is still uncertain, hampering conservation, especially in the diverse tropical regions of Earth. Here we use the plant family Bromeliaceae as a model to explore the history and future of species discovery from the Neotropics global biodiversity hotspot. - We use a newly curated complete list of described species together with species geographic distributions and information on taxonomic authors to explore patterns of past species description. Furthermore, we use logistic models to estimate the expected number of species in the family, the subfamilies, the largest genera and the relationship with geographic range. - In the past species discovery was dominated by researchers from Europe (mid-18th to mid-20th century), then researchers from the USA (mid to end of 20 century) and finally researchers from Latin America (21st century). The average number of species described per year increased from 0.6 between 1750 and 1800 to 33.8 between 2001 and 2025. Furthermore, description shifted from widespread species to species with smaller ranges, mostly from Brazil and the Andes from Bolivia to Mexico. We project the expected number of Bromeliaceae species at 6,658 to 7,498, leaving the current number of described species only at 55 to 49%. - Our results illustrate changes in the history of species description in the last centuries, confirm the progression from large range to smaller range species as the taxonomic treatment of the groups progressed, and illustrates Brazil, Mexico and the Andean region as hotspots for future species description.