Oryx Voi 33 No 3 J..l\ ' JdO Conservation of the Juan Fernandez firecrown and its island habitat Michael S. Roy, Juan Carlos Torres-Mura, Fritz Hertel, Marina Lemus and Renate Sponer Abstract The Juan Fernandez Islands constitute two probably a very recent invader; (iv) maintains some distantly separated (182 km) major islands, of which genetic variation, although significantly lower than that Isla Robinson Crusoe is the closest (667 km) to the found in the green-backed firecrown island population. Chilean mainland, and a number of smaller surrounding Because of their relatively recent divergence the authors islets. The endemic Juan Fernandez firecrown Sephanoides aimed to find out if the two species compete for re- fernandensis once inhabited both major islands and sources. In addition, they assessed the conservation numbered many thousands. Today it exists only on Isla options for the Juan Fernandez firecrown and provided Robinson Crusoe and numbers just a few hundred. recommendations for its management. They concluded Another hummingbird, the green-backed firecrown that the survival of the Juan Fernandez firecrown is S. sephaniodes, inhabits this island but also occurs on the inextricably linked to the holistic restoration of eco- mainland. The islands are in ecological meltdown as a system/community function of the island. The initial result of the removal of much of the native (largely step must involve the removal of introduced mammals, endemic) biota. This degradation has been exacerbated followed by replanting of native flora. Although the by introduced herbivorous and carnivorous mammals, authors do not support the use of captive propagation which are extirpating all that remains. In a previous as a general conservation tool, they believe that, be- investigation the authors assessed the evolutionary re- cause the Juan Fernandez firecrown is composed of lationships and genetic variation in the Juan Fernandez only one small population that is under extreme threat firecrown population. They showed that the species: of extinction, a captive population should be estab- (i) is a relative of the high Andean hummingbirds; (ii) lished. is a close sister species of the green-backed firecrown; (iii) dispersed to the islands approximately 0.5-1 million Keywords Conservation, introduced mammals, years ago, unlike the green-backed firecrown, which is islands, Juan Fernandez firecrown, restoration. often found nowhere else. Although islands contain the Introduction most endangered ecosystems, they are also potentially Species on islands constitute a disproportionate number the easiest to conserve and restore. Because they are of the total number of threatened species on this planet independent and isolated, permanent removal of non- as a result of their often small population sizes, and native organisms and management of resources are vulnerability to natural and human-induced environ- relatively easy. However, for full restoration to be mental catastrophes (see Cronk [1997] for a full discus- successful, extinction of endemic organisms must be sion). Since 1600, 75 per cent of animal extinctions have avoided and their conservation made a priority. been of island species (Reid & Miller, 1989). Further- We visited the oceanic Juan Fernandez Islands (Chile) more, although only 20 per cent of bird species live on during the summer months of 1995-96, 1996-97 and islands, 90 per cent of extinct birds (in recent history) 1997-98 with the goal of investigating the evolutionary were from islands (Myers, 1979). However, the import- relationships of the Juan Fernandez avifauna, such as: ance of island species for conservation and mainten- phylogenetic relationships between island and main- ance of global biodiversity is high because they are land species, approximate time of dispersal to the islands, and amount of morphological and genetic change accompanied by their isolation on the island. Michael S. Roy (corresponding author) and In addition to these questions we have also attempted Renate Sponer Department of Zoology, University of Otago, to: (i) further our understanding of the biology of Dunedin, New Zealand. E-mail: [email protected] the islands' endemic flagship species, the Juan Juan Carlos Torres-Mura and Marina Lemus Museo Nacional de Fernandez firecrown (Trochilidae: Sephanoides fernan- Historia Natural, Casilla 787, Santiago, Chile. densis), whose preservation is critical if full restoration Fritz Hertel Department of Biology, University of California, of the unique and biologically rich Juan Fernandez Los Angeles, CA 90024, USA. Islands is to be achieved; and (ii) provide practical Received 21 August 1998. Accepted 2 December 1998 1999 FFI, Oryx, 33(3), 223-232 223 Downloaded from https://www.cambridge.org/core. IP address: 170.106.35.234, on 24 Sep 2021 at 12:11:56, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1999.00067.x 224 M. S. Rov et al. conservation plans for this end. Already designated as portion of this flora is endangered and two species are a world biosphere reserve, these islands have massive already extinct. The Juan Fernandez flora has diverse potential for conservation, biological research activities origins; the Lactoridaceae are otherwise known only (comparable to the Galapagos), and sustainable eco- by fossil remains from South Africa whereas the tourism, given the correct infrastructure and manage- marine algae have their origins in the Australasian ment goals. region. Forty-five per cent of the fern species are endemic, with one endemic monotypic genus, Thryrsopteris (Ricci, 1996). The Juan Fernandez Islands The native terrestrial fauna, derived from the South The Pacific archipelago of Juan Fernandez, a chain of American mainland, shows comparable endemicity. For young oceanic volcanoes, includes two principal ex- example, 35, of 46 species of mollusc and 440 of 687 posed peaks: Isla Robinson Crusoe or Masatierra (Fig. species of insect are endemic. The native vertebrate 1; 93 sq km, 33°40'S, 78°33'W), which is located 667 km fauna consists of land and sea birds and one species of west of the Chilean coast and is estimated to be 3.8- fur seal (there are no native amphibians or reptiles). 4.2 million years old (Stuessy et al., 1984), and Isla There are nine terrestrial bird species, three of them Alejandro Selkirk or Masafuera (85 sq km, 33°45'S, endemic to the archipelago: the Juan Fernandez fire- 80°51'W), which is located 182 km west of Isla crown Sephanoides fernandensis (Trochilidae) and the Robinson Crusoe and is estimated to be 1.0-2.4 million Juan Fernandez tit-tyrant Anairetes fernandezianus years old (Bourne et al., 1992). The Juan Fernandez (Tyrannidae) of Isla Robinson Crusoe (Roy et al, 1999), Islands have never been connected to the mainland. and the Masafuera rayadito Aphrastura masafuerae The Juan Fernandez Islands contain 142 species of (Furnariidae) from Isla Alejandro Selkirk. Three avian vascular plants of which 69 per cent of species and subspecies are endemic to the Islands: Falco sparverius 18 per cent of the genera are endemic. The endemic fernandezianus (Falconidae) inhabiting both islands, and plants include the only living relict of the family Buteo polyosoma exsul (Accipitridae) and Cinclodes Lactoridaceae, Lactoris fernandeziana, and a remarkable oustaleti backstmemi (Furnariidae) on Isla Alejandro radiation of Compositae, which includes cabbage trees Selkirk. The three other species are also found in main- in the genus Dendroseris. Unfortunately, a high pro- land Chile: short-eared owl Asio flammeus, green-backed Caleta la Vaqueria Isla Robinson Crusoe Cumberland Bay ^—— San Juan Bautista Pte. Frances 5km Fig. 1 Isla Robinson Crusoe (93 sq km). Stippling indicates the principal areas containing native vegetation. They coincide largely with steep hillsides and ridges. 1999 FFI, Oryx, 33(3), 223-232 Downloaded from https://www.cambridge.org/core. IP address: 170.106.35.234, on 24 Sep 2021 at 12:11:56, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1999.00067.x Conservation ot the Juan Kernancisz firecrown and its island habta: 225 from Europe to continental Chile and then to the islands). Ricci (1996) suggested little change in the distribution of native ferns since the first botanical collections were made in 1823 (Graham, 1824), 1824 (Douglas, 1836) and 1830 (Bertero, 1830), 250 years after the islands' discovery. This is surprising given the gross anthropogenic changes made to the environment since then and their effects on the angiosperm flora. The native fauna is directly affected by introduced mam- mals such as rodents and coatis Nasua nasua, which have been implicated in the predation of birds. The demography and biology of the Plate 1 An eroded hillside denuded of topsoil. Native evergreen hummingbirds forest would probably have covered this region just over 100 years ago (M. Roy). The Juan Fernandez Islands are listed as a priority 1 (critical) Endemic Bird Area of the World (Stattersfield et ah, 1998). Rottmann & Lopez-Calleja (1990) listed firecrown Sephanoides sephaniodes and austral thrush Sephanoides fernandensis as one of the most endangered Turdus falcklandicus. The California quail Callipepla cali- bird species in Chile. Listed as Critically Endangered fornica was introduced to Isla Robinson Crusoe at the in the IUCN red list (Collar et aL, 1994; IUCN, 1996), it beginning