Hmeljevskia et al. 2014 (Article) Pitcairnia

Conservation assessment of an extremely restricted bromeliadhighlights the need for population-based conservation on graniticinselbergs of the Brazilian Atlantic Forest

Author(s):—K.V. Hmeljevskia, L. Freitasb, R. Dominguesc, A.R. Pereirad, A.S. Canciob, A.C.S. Andradeb, M.A. Machadoe, L.F. Viccinic & R.C. Forzza

Corresponding email:—leandro@jbrj.gov.br

Publication:—Flora 209: 250–259. (2014) — DOI

Abstract:—Inselbergs support highly specialized vegetation with many endemic species. Here we studied by anintegrated approach a rare and threatened species from Brazilian inselbergs. Pitcairnia encholirioides(Bromeliaceae) is included in the Red Book of Brazilian Flora, in the ‘Endangered’ category. Only onesingle population on unprotected private property was known at the beginning of our study. We studiedseveral life-history traits including clonal growth, reproductive biology, seed germination and cryopreser-vation, and genetic diversity. Pitcairnia encholirioides has the phalanx type of clonal growth strategy. Itsself-incompatible flowers are successfully pollinated by hummingbirds. However, less than 5% of clonalfragments produced flowers. Seeds can be wind-dispersed, but most of them are dispersed by gravityand fall close to the mother plant. The percentage and speed of germination were significantly affectedby different temperatures, water potential, and red:far-red light ratios, although more than 80% of seedsgerminated under optimal physiological conditions. The genetic diversity was very low (Hsp= 0.09) andthe population was highly structured (ST= 0.51). The combination of dispersal mode and environmen-tal conditions seems to be the main factor leading to the rarity of P. encholiroides. Low genetic diversitycombined with small population size and low reproductive capacity suggest that the species is highlysusceptible to environmental disturbance. Similarly to P. encholiroides, many species from Brazilian insel-bergs are restricted to only a few localities. For more widely distributed species, a higher genetic diversityamong populations has been consistently detected. The pattern of low gene flow of many species withsmall distributions highlight the importance of population-based conservation strategies for such taxathe areas of occurrence of which being naturally fragmented at inselberg sites. We discuss some strategiesthat may help in conservation of such species.

Keywords:—Clonal plants Endangered species Endemism Ex situ conservation In situ conservation Rarity