Growth dynamics of endemic Dracaena cinnabari

Dragon ́s blood tree, a flagship endemic species of Socotra, is threatened with extinction 23 due to lack of natural regeneration, likely because of goat herbivory and/or climatic factors. Loss of 24 dragon ́s blood tree would result in loss of other native flora, heightening the importance of 25 formulating a conservation strategy for it. Although artificial afforestation might be used to offset 26 the lack of natural regeneration, it would have to overcome the same threats faced by naturally 27 occurring seedlings. Moreover, there is no published information on the growth dynamics of 28 seedlings in plantations in situ on Socotra. To fill this information gap, we compared seedling 29 growth over an 8-year period after planting at three sites that differed in the degree to which goats 30 were excluded and in whether they were watered regularly over the period. In addition to 31 developing a new classification of the growth stages, which will enable better tracking of population 32 dynamics, we found that continuous goat exclusion was necessary to prevent seedling mortality. 33 Also, although seedling growth overall was slow, growth parameters of regularly irrigated 34 seedlings ranged from 156 % to 446 % of those not regularly watered, suggesting that this treatment 35 can speed seedlings’ escape from goat browsing. 36