The natural communities of the Juan Fernández Islands are biologically unique. Although the archipelago’s flora has received considerable scientific attention (see the works of Tod Stuessy et al.), the fauna of the islands has not been as well researched. Changes to the native systems of the islands, beginning with the arrival of humans in 1574, have continued unabated, and much of the native flora and fauna are at risk, exhibiting population declines worthy of alarm.
Seventy-three percent of the endemic angiosperms are threatened with extinction (1). Four of the six locally breeding seabird species are listed by the IUCN as vulnerable (2). One landbird is recognized as critically endangered, and two others as vulnerable and near threatened. The Juan Fernández fur seal is listed by the IUCN as vulnerable (2), and is still recovering from near extinction in the 1800s.
The archipelago is currently home to many species of introduced and invasive
plants and mammals (cattle, cats, coati, goats, mice, rabbits and rats). Introduced
species of mammals on islands can cause extensive damage to native systems by
grazing, competition with native species, habitat destruction, and predation.
Preliminary studies (see Research page) suggest that introduced mammals directly
impact our focal seabird species through predation (cats, rats and coatis),
competition for burrows (rabbits), and destruction of burrows (cattle). Potential
indirect effects due to changes in the plant community via herbivory and grazing
include increased erosion, compacted soils and compromised nesting habitat.
We are discussing the possibility of concerted eradication efforts with local islanders, local, regional, and national officials from the Corporación Nacional Forestal (CONAF, the national park administration agency), other Chilean agencies, Chilean ecologists, and eradication experts from the US, Ecuador, and New Zealand.
We also feel that restoration efforts are warranted, but we encourage the implementation of eradication efforts prior to investment in large-scale restoration. Without eliminating the threats posed by invasive species, restoration efforts run the risk of being undermined by their effects.
(1) Stuessy et al. 1992. Aliso 13(2): 297-307
(2) International Union for the Conservation of Nature and Natural Resources