Orchids from Rio Grande Do Sul, Southern Brazil: What We Know and What We Still Have to Know to Ensure Their Conservation

Rio Grande do Sul (Brazil) has significant orchid biodiversity and is the birthplace of several cultivated Epidendroideae species, especially in the genera Cattleya (Laeliinae) and Gomesa (Oncidiinae), mostly from the threatened Atlantic Rainforest. In contrast, the grassy Pampa Biome has remarkable diversity of terrestrial Orchidoideae species, especially in the subtribes Spiranthinae, Chloraeinae (Chloraea and Bipinnula), and Orchidiinae (Habenaria); many have cultivation potential. Considering the published literature with information relevant to the in situ and ex situ conservation of these species, the following patterns arose: (1) the basic reproductive biology (natural pollination, breeding systems) is better known in Epidendroideae orchids, (2) reliable protocols to store and germinate seeds are available for Cattleya species, but are still being developed or have to be developed for other orchid groups, (3) so far, reintroduction experiments have only been performed for Cattleya intermedia, a commercially relevant species, and (4) several endangered species are not yet represented in conservation units. In addition, we present new information pertinent to seed germination in some taxa. In this context, we thus strongly suggest the following steps: (1) to perform considerable additional fieldwork to locate still overlooked populations, especially for threatened species, (2) the creation of Conservation Units, especially for endangered species not protected yet in situ, (3) promoting ex situ protection by cultivation in Botanical Gardens or analogue collections, coupled with the storage of seeds and/or pollinia in germplasm banks, and (4) encouraging local researchers to propagate native species and perform reintroduction/restoration experiments.