Diversity and distribution of the last remnants of endemic juniper woodlands on Tenerife, Canary Islands
Identifying ecological requirements, species diversity patterns and distribution ranges of habitats of interest is an important task when developing conservation and restoration programs. The Canarian juniper woodland formed by Juniperus turbinata ssp. canariensis is listed as a priority habitat by the European Union. Although very common in the past, this vegetation type has suffered immense destruction and degradation over the last five centuries on the Canary Islands, especially on the largest most populated island of Tenerife. We evaluated the geographical distribution range of the last remnants of Canarian juniper woodlands on Tenerife and analyzed their ecological status, floristic composition and plant species diversity. Despite the degradation of the original vegetation, we still observed outstanding species diversity. Endemic species richness and number of typical habitat species were best predicted by summer rainfall, which seems to be the limiting factor for this habitat in the lower drier regions. Human disturbance has had a negative effect on endemic species richness but a positive effect on the distribution of alien plants, highlighting the potential threat to this habitat. Ecological characterization and floristic composition were most influenced by climatic factors related to the dichotomy of a humid windward and a drier leeward slope of the island and by altitude. However, vegetation structure and human disturbance also determined species composition. Environmental requirements indicated a circuminsular potential distribution of this habitat. Given the exceptional plant diversity, the scarcity of dense stands and the low protection status, immediate protection of the remaining stands and future restoration programs should be the priority for conservation strategies of this endemic vegetation type.