Article

The distribution of the orchid Barlia metlesicsiana is restricted to the Canary Island of Tenerife. We monitored Barlia metlesicsiana and its pollination success in four representative subpopulations on Tenerife during the years 2004 to 2010. Despite some yearly fluctuations (Bernhardt & al. 2009), the study years 2004, 2005, and 2007 indicated relatively constant population sizes (230 to 246 plants observed per year), and reproductive success was also relatively constant throughout the years 2004, 2005 and 2006 (yearly fruit set of 26.0% to 36.6%). However, following a fire in July 2007 number of plants, proportion of flowering plants, and pollination success dropped down dramatically: in the first two years after the fire (i.e. 2008- 2009) altogether only three plants managed to flower, and only one of those plant individuals obtained pollination. In 2010, subpopulations beginning recreation were still characterised by low absolute number of plants, but with the highest proportion of individuals flowering as observed throughout all seven study years (33.7%). However, pollination success (fruit set of 21.0%) was still at the lower end of the regular yearly fluctuations of this species. Therefore, our data show a strong influence of catastrophic events (i.e. fire) not only on the appearance and dormancy of terrestrial orchids in general, but also more specifically on the pollination success of the endangered orchid Barlia metlesicsiana on Tenerife.