Dendroseris neriifolia (Dendroseris neriifolia)

Mohamed bin Zayed Species project number 11251770

 

Juan Fernandez Archipelago (JFA) is recognized for its unusual and highly endemic vascular flora (Anderson et al. 2001). Out of a total of 213 native vascular plant species, 133 species (62.3%) and 11 genera (13%) are endemic to the islands (Danton et al. 2003). 

 

JFA terrestrial ecosystems are a dramatic biological conservation case, which is exacerbated on Robinson Crusoe Island. Since human occupation of the island, native vegetation cover was replaced by open areas and overexploited. Currently most of the land suffers from strong soil erosion. Moreover, the increasing spread and aggressive occupation of the island by three exotic invasive shrubs, Aristotelia chilensis, Rubus ulmifolius and Ugni molinae has increased habitat loss for native plants. Feral exotic mammals, including goats, european rabbits and rats, destroy native plants and prevent recovery of vegetation. The combined effects of these threats have led to the reduction of many native species populations and the depletion of genetic variability (Stuessy et al. 1997), with several species reduced to few isolated individuals.

The threats on the Juan Fernandez Islands have resulted in a high risk of extinction for the majority of native plant species. Currently more than 70% of Juan Fernández endemic plant species are globally listed. Eight species are been classified as extinct, 52 Critically Endangered, 37 Endangered and nine Vulnerable to extinction (Ricci 2006).

In this project we focus on eight endemic plant species of Robinson Crusoe Island. The primary target foci are three giant species of the genus Dendroseris: D. neriifolia, D. macrantha and D. marginata. Also we will evaluate the most appropriate conservation strategies for five additional species of which we have little information about their population size, distribution or threats: Yunquea tenzii (arboreal herb), Centaurodendron palmiforme (arboreal herb), Chenopodium crussoeanum (shrub), Greigia berteroi(bromeliad herb) and Elaphoglossum squamatum (fern). All Dendroseris and Centaurodendron species investigated here are listed as Critically Endangered (IUCN 2010). While Yunquea tenzii, Chenopodium crussoeanum and Greigia berteroi are not currently listed by the IUCN, all were evaluated by Ricci (2006) using IUCN criteria, resulting in classifications as Critically Endangered.

Between 2009-2010 in collaboration with Juan Fernandez´s park rangers, we systematized and created a GIS platform with locations and current status of critically endangered plant species populations (Faúndez 2010). Rangers continue to monitor critically endangered plants and to search for new individuals of these species. However, there are currently no conservation or restoration efforts aimed at halting the extinction of these species in situ or ex situ (with exception 35 individuals of D. neriifolia that were planted this year without rabbit-proof fences, due to a lack of resources). It is necessary to evaluate and address threats to these endangered plants posed by introduced mice and rats and rabbits that chew bark and introduced shrubs that cover them.

The project objectives are as follows:

1. To prevent extinctions in the wild of endemic plant species with less than 150 known individuals.

2. To control and minimize major conservation threats, and to restore habitat around the remaining subpopulations of critically endangered plant species on Robinson Crusoe Island.

3. To conduct a re-introduction program of Dendroseris species to increase number of individuals in wild populations.

4. To assess the current conservation status of these eight species, and to generate long term conservation plans with proposed management actions.