Poster

         Floristics & Taxonomy

A review of the woody bamboos (Poaceae: Bambusoideae: Bambuseae) of Trinidad and Tobago

Presenting Author
Christopher Tyrrell
Description
The dual island nation of Trinidad and Tobago is an important keystone for neotropical woody bamboo taxonomy. Trinidad is a type locality for two widely applied but poorly defined species: Arthrostylidium pubescens Rupr. and A. excelsum Griseb. and two potentially endemic species: Chusquea cylindrica L.G. Clark and Rhipidocladum prestoei (Munro) McClure. Few resources exist for the islands to adequately identify all the woody bamboo species that putatively grow there. The serialized vascular flora of Trinidad and Tobago, for instance, lacks a treatment for Poaceae. Moreover, the most speciose native genus, Arthrostylidium, is only partially revised, with the emphasis on the South American species and not those of the West Indies. Our objective is to critically review the woody bamboos of Trinidad and Tobago, clarify which species are or have been known from the islands, and provide an identification key, species accounts and distribution maps for the revised list of taxa. We conducted fieldwork campaigns in 2022 and 2023, and reviewed herbarium specimens and human observation records of woody bamboos from the islands. Newly collected specimens were vouchered and all woody bamboo records were georeferenced and plotted using QGIS v.3.24. Estimates of species distribution models (SDM) were generated for several species growing on the islands. We confirmed three species of native woody bamboo and three species of introduced woody bamboo were extant on Trinidad. An additional three western hemisphere species may have dynamic occurrence on the island(s). Native species diversity correlated well with previously identified floristic hotspots. One introduced species, B. vulgaris, is common on Tobago. To the best of our knowledge, there are currently no native woody bamboo species present on Tobago, however, A. pubescens appears to have been growing along the Main Ridge in the past. The historic presence of some species not currently found may indicate an instance of source-sink populations dynamics between the islands and mainland South America.