The narrow range of Alcantarea martinellii, which consists of few isolated populations, is typical for inselberg species of Alcantarea (Barbará et al., 2007), and reinforces the necessity of further conservation measurements to protect the species. In general, inselbergs suffer from extensive habitat loss and degradation. Local people usually set fire to the vegetation, which is then used as pasture for goats (M. de Moraes, pers. comm.). As pointed out by Guedes-Bruni and Lima (1997), the destruction of forest around some high-altitude granitic outcrops of the mountain ranges of Rio de Janeiro State has made their native vegetation susceptible to fire. This susceptibility is further aggravated by the invasion of the African grass Panicum maximum Jacq. Based on the IUCN criteria (IUCN, 2001), A. martinellii can be included in the conservation status of Critically Endangered due to its restricted occurrence in an area estimated to be less than 100 km2 and the projected decline in the quality of the habitat.
This species was recently recollected by Miguel de Moraes in the Pedra do Oratório region where it forms small vegetation mats with Alcantarea imperialis (Carričre) Harms, Pitcairnia glaziovii Baker (Bromeliaceae), and Worsleya rayneri (Hook.f.) Traub & Moldenke (Amaryllidaceae), along with assorted Poaceae, Velloziaceae, and Orchidaceae (Fig. 2). Utricularia nelumbifolia Gardn. (Lentibulariaceae) sometimes grows inside the rosette of Alcantarea martinellii. —SeeLasser & Maguire 1950
