Habitat and conservation status of molinillo (Magnolia sambuensis) and laurel arenillo (Magnolia katiorum), two endangered species from the lowland, Colombia

Abstract

The conservation of the Magnoliaceae family is considered a priority worldwide, especially in Colombia, where all of its 36 species are seriously endangered while frustratingly little is known about their ecology. We therefore, assessed some ecological aspects of two lowland forest species: laurel arenillo ( Magnolia katiorum) and molinillo ( M. sambuensis). The first is an endemic species of the Urabá region in northwestern Colombia, and the second is distributed from Panama to Colombia along the Chocó Biogeographical region. Both species have a very low tree density and are found in forest stands that are disturbed by the timber exploitation of valuable woody species. The trees of both species had an average height of 26 m and shared similar environmental conditions such as soil (25°C) and air (28°C) temperatures, soil moisture (113%), and slope (25%). A redundancy analysis showed that each Magnolia species grows in a different community. Laurel arenillo was not a clear dominant species in a more diverse forest community, and was positively associated to altitude, longitudinal slope, and soil humidity. In contrast, molinillo was positively associated to air temperature and transversal slope and was negatively associated with longitudinal slope. This species was the most dominant in its community, which was less diverse than that of laurel arenillo. The last species should be considered a priority for conservation while the conservation status of molinillo should be further reviewed. Both species displayed large, fragrant, eye-catching flowers throughout most of the year.