Marine Biodiversity in Juan Fernández and Desventuradas Islands, Chile: Global Endemism Hotspots

Abstract

The Juan Fernández and Desventuradas islands are among the few oceanic islands belonging to Chile. They possess a unique mix of tropical, subtropical, and temperate marine species, and although close to continental South America, elements of the biota have greater affinities with the central and south Pacific owing to the Humboldt Current, which creates a strong biogeographic barrier between these islands and the continent. The Juan Fernández Archipelago has ~700 people, with the major industry being the fishery for the endemic lobster, Jasus frontalis. The Desventuradas Islands are uninhabited except for a small Chilean military garrison on San Félix Island. We compared the marine biodiversity of these islands across multiple taxonomic groups. At San Ambrosio Island (SA), in Desventuradas, the laminarian kelp (Eisenia cokeri), which is limited to Desventuradas in Chile, accounted for >50% of the benthic cover at wave exposed areas, while more sheltered sites were dominated by sea urchin barrens. The benthos at Robinson Crusoe Island (RC), in the Juan Fernández Archipelago, comprised a diverse mix of macroalgae and invertebrates, a number of which are endemic to the region. The biomass of commercially targeted fishes was >2 times higher in remote sites around RC compared to sheltered locations closest to port, and overall biomass was 35% higher around SA compared to RC, likely reflecting fishing effects around RC. The number of endemic fish species was extremely high at both islands, with 87.5% of the species surveyed at RC and 72% at SA consisting of regional endemics. Remarkably, endemics accounted for 99% of the numerical abundance of fishes surveyed at RC and 96% at SA, which is the highest assemblage-level endemism known for any individual marine ecosystem on earth. Our results highlight the uniqueness and global significance of these biodiversity hotspots exposed to very different fishing pressures.

Improving marine conservation planning in a time of global change

“…These overlaps are higher for species with large home ranges, such as marine mammals (8.4% average overlap), and lower for groups with more coastal distributions, such as reptiles (2.6% average overlap; Table S3.2). Marine wilderness overlaps with areas of high species richness, range rarity and proportional range rarity (see methods; Figure S3.3-3.4), and also with previously identified hotspots of both functional diversity, such as the Gulf of Carpentaria in Australia (Stuart-Smith et al 2013); and of species endemism, such as the Desventuradas islands West of Chile (Friedlander et al 2016). On average, global wilderness areas have 31% higher species richness, 40% higher range rarity and 24% higher proportional range rarity than non-wilderness areas, though this varies substantially across marine ecoregions (Table S3.3).…”

“…Human pressures across the ocean are increasing rapidly and nowhere in the sea is entirely free of human impacts (Halpern et al 2008(Halpern et al , 2015. We show that there is very little marine wilderness in coastal areas, with most remaining wilderness relegated to extreme latitudes or the high seas ( Wilderness areas can also exhibit extremely high endemism (Friedlander et al 2016) and…”

“…These wilderness areas contain high genetic diversity, unique functional traits and endemic species Pinsky & Palumbi 2014;Friedlander et al 2016;D'agata et al 2016); maintain high levels of ecological and evolutionary connectivity (Jones et al 2007;Grober-Dunsmore et al 2009;Haddad et al 2015); and may be well 15 anthropogenic stressors and also a very low combined cumulative impact from these stressors. We discover that ~13% of the ocean meets this definition of global wilderness, with most located in the high seas.…”

Peer Review #2 of "A new species of Atrimitra Dall, 1918 (Gastropoda: Mitridae) from seamounts of the recently created Nazca-Desventuradas Marine Park, Chile (v0.2)"

“…It is interesting to note that species of the family Mitridae found around Easter Island, Strigatella flavocingulata (Lamy, 1938), Imbricariopsis punctata (Swainson, 1821) and Neocancilla takiisaoi (Kuroda, 1959), reviewed in Osorio (2018), on the far western side of the Salas y Gómez ridge, are all Indo-Pacific species, with ranges across the Indian and Pacific Ocean. The new species has no morphological affinities with them and available evidence suggests that it is found only on seamounts of this region, which hosts a fauna characterized by the high levels of endemism (Friedlander et al, 2016). An interesting ecological observation is that some specimens of A. isolata sp.…”

“…In 2015, Chile created the large Nazca-Desventuradas Marine Park (NDMP), covering almost 300,000 km 2 of this remote part of the SE Pacific. Comprising San Ambrosio and San Félix Islands (known as Desventuradas Islands), and the seamounts located northwest of them, at the intersection of the Salas y Gómez and the Nazca Ridges, this park aims to protect the unique marine fauna inhabiting this area, recognized as a hotspot of species endemism (Fernández et al, 2014;Friedlander et al, 2016). As an example, the estimated endemism of fishes, one of the few groups for which enough information exists, is about 40% (Friedlander et al, 2016).…”