Growth Dynamics of Endemic <em>Dracaena cinnabari</em> Seedlings <em>In Situ</em> on Socotra Island

Abstract

Dragon´s blood tree, a flagship endemic species of Socotra, is threatened with extinction due to lack of natural regeneration, likely because of goat herbivory and/or climatic factors. Loss of dragon´s blood tree would result in loss of other native flora, heightening the importance of formulating a conservation strategy for it. Although artificial afforestation might be used to offset the lack of natural regeneration, it would have to overcome the same threats faced by naturally occurring seedlings. Moreover, there is no published information on the growth dynamics of seedlings in plantations in situ on Socotra. To fill this information gap, we compared seedling growth over an 8-year period after planting at three sites that differed in the degree to which goats were excluded and in whether they were watered regularly over the period. In addition to developing a new classification of the growth stages, which will enable better tracking of population dynamics, we found that continuous goat exclusion was necessary to prevent seedling mortality. Also, although seedling growth overall was slow, growth parameters of regularly irrigated seedlings ranged from 156 % to 446 % of those not regularly watered, suggesting that this treatment can speed seedlings' escape from goat browsing.