Easter Island: Ecoregion at the Edge of the World

The popular religious holiday that occurs near the northern spring equinox goes by a number of names. Easter. Resurrection Sunday. Pasch. Whatever it is called, the majority of the world’s 2 billion or so Christians observe this holiday with regional variations of religious activities, customary foods, and symbols. Common traditional proceedings include parades and religious services, but much of the fun is directed at the youngest attendees. For small children, the holiday is the most egg-focused spectacle they’ll see until they reach adolescence and discover the decorative inspiration of Halloween. Kids spend the day giving eggs food coloring swirlies, embarking on crazed, egg-based scavenger hunts, and, for some reason, palling around with a vaguely leporid husk filled with fear-sweat and the voiceless madness that reaches out from the Void. For godless heathens such as myself, Easter mostly functions as an annual excuse to wear a classy-as-shit collared shirt, get together with fine folks, inhale brunch and booze, enthusiastically and inefficiently stagger around the grounds in a quest for plastic eggs, and to catapult my pancreas into sputtering death-fits after shamelessly replacing much of the liquid in my body with a Marshmallow Peep-derived sugar slurry.


Re-enactment: Easter Sunday 2016

The only other association I have with Easter….outside of that day of the year when I thoroughly test every major organ system in my body through the gross irresponsibility of facilitating a gastrointestinal nuclear holocaust….is a place, not an event. And because I’m a HUGE nerd, I’m obviously talking about a small island in the southeast Pacific known as Easter Island. To the Chileans, who currently have political jurisdiction over the island and categorize it as a special territory, it is “Isla de Pascua.” The original Polynesian inhabitants of the island were the first to name it, and while there is considerable debate about what exactly the island was called long before Europeans ever set foot on it, for the last century and a half, the Polynesian name for the island has been “Rapa Nui,” a term that has also come to denominate the native inhabitants of the island, and the language originally spoken there.

The South Pacific is sprinkled with a multitude of small volcanic islands and coral atolls that spread eastward from Indonesia and Australia; Fiji, Tonga, Samoa, Tokelau, the Society Islands, the Gambier Archipelago, the list goes on. The expanses of open ocean between many of these islands and island chains are not insignificant, but nowhere is the level of isolation as extreme as in Rapa Nui. Rapa Nui sits in the subtropical zone, some 27 degrees south of the Equator. It is located at the most southeasterly point of the vast, triangular Polynesian cultural region, representing the furthest eastward extent (that we know of) of Polynesian diaspora and colonization, much like how Hawai`i and New Zealand sit at the northern and southern extremes of the region, respectively.

The nearest large landmass (South America; northern Chile, specifically) is 2,300 miles (3,700 km) directly east from there, and the nearest inhabited island of any kind is Pitcairn Island…more than 1,200 miles (about 2,000 km) to the west….an island that is only about two miles across, and was perhaps only sporadically inhabited up until a few hundred years ago, when it became wholly deserted. The closest bit of land of any kind is Isla Salas y Gómez (Manu Motu Motiro Hiva), about 250 miles (400 km) to the northeast, but this tiny fleck of exposed, volcanic rock only covers about 37 acres…which means it’s only one third as expansive as the Mall of America. Thus, Rapa Nui’s closest neighbors are even more diminutive than it is, which doesn’t exactly assist with the whole extreme isolation thing. The situation reminds me of when I lived in rural, central Idaho as a child. The tiny, high-desert town I lived in (Challis) only contained about 900 rugged souls, all of which grunted out a living 150 miles away from the nearest hospital, movie theater, or fast-food franchise. However, there were towns that existed out in the Great Brown Nothing between my town and the nearest semblance of civilization. But they were puny, the barely-discernible petechiae blemishing the pale, wrinkly, boundless expanse of septuagenarian back skin that is the State of Idaho. Our closest neighbor, a hour’s track away on lonely Highway 93, was the community of Mackay…..half the size of our own town. Good ol’ Challis, Idaho wasn’t much, but it was the biggest hub by far for many, many, many miles….much like Rapa Nui.

So yes, Rapa Nui sits way out in the ass end of nowhere, atop a seamount that has formed via the Easter hotspot, an upwelling of magma below the oceanic crust that has generated a range of undersea mountains (the Nazca Ridge) as the Nazca Plate drifted above it….nothing around it for many blue, featureless miles. However, this extreme isolation wasn’t enough to keep humans away, at least not for forever.

Rapa Nui was first colonized by Polynesian settlers (probably from Mangareva (in the Gambier Archipelago) to the west, or the Marquesas in the northwest) sometime around 1200 AD or so, making it nearly the last place in the Pacific to be discovered and settled by Polynesian peoples (New Zealand was more recently settled, around 1300 AD). It was the Rapa Nui society that persisted on the island completely solo until the 1720s, when Dutch explorer Jacob Roggeveen stumbled across the place (as one does) on Easter Sunday…giving it the name “Paasch-Eyland”, Dutch for “Easter Island.” The Rapa Nui people are of course quite famous for their proclivity for carving impressively massive, stern-faced statues out of the compressed volcanic ash found on one of the island’s main volcanoes.


You know, these fellas.

Nearly 900 of these figures (called “moai”) are known to exist in modern times either on the island (or in museum collections), and can consist of nothing but the regularly referenced “Easter Island heads” or heads and bodies that are complete down to the waist or thighs. Moai are so enigmatic and stark against their often open, rolling backdrops that they’ve managed to lend inspiration (with varying levels of cultural sensitivity) to various elements of modern popular culture, from Pokemon to major settings in early Mario videogames to Spongebob’s buzzkill of a neighbor’s house.

If you’re looking at the empty, treeless plains that cover the island and thinking “how in the everloving fuck did the Rapa Nui craft and move these things around? There’s not a trace of raw materials necessary for pushing, pulling, or carving jack shit!” you and decades of archaeological pondering have something in common. The thing is, when the first Polynesian settlers arrived on Rapa Nui, the island was covered in thick, subtropical forests. Within a few hundred years, around the time Europeans first saw the island, nearly every single tree was gone. Various explanations have been thrown around as to how and why Rapa Nui’s forests vanished; the most popular of which has been that this is a story of environmental degradation on a micro-scale precipitated by human overpopulation, limited resources, and eventual societal collapse (although more recently, it’s been suggested that European-introduced disease and slavery may have been the driving factor for societal and population decline, while the rats that were stowaways with the Polynesian settlers’ canoes did short work of the island’s vegetation). Whatever the cause, the native forests of Rapa Nui are kaput, which is a damned shame considering that Rapa Nui’s extreme geographic isolation means that much of the island’s native flora and fauna were (and are, for those that haven’t yet become extinct) unique, in an ecological and evolutionary sense.

I’ve written about bioregions before (in particular, about the biogeographical province that makes up the far Northwestern corner of the State of California), the biogeographic units that make up large “burroughs” of ecologically and geographically linked assemblages of organisms. Ecoregions are smaller than bioregions; they are the “neighborhoods” within the bioregional burroughs…and the pre-human settlement terrestrial environment of Rapa Nui falls under the “Rapa Nui and Sala y Gomez subtropical broadleaf forest” ecoregion, a tiny, but distinct ecological area limited to the island and its peewee neighbor to the northeast. Due to the island’s insane levels of isolation, large proportions of the limited wildlife and vegetation it was host to were/are evolutionary distinct from similar species on the mainland and other Pacific islands, with many species found nowhere else on the planet (a situation known as local “endemism”). The majority of species most people are familiar with are like wildly-successful chain restaurants like McDonald’s; you can find them over a large geographic range, from Juneau to Belfast to Seoul, with relatively little alteration between locations (well, with the exception of some menu items, like Germany’s bratwurst and mustard facefuck, “Das Nürnburger” or the fried potato and shrimp burgers served in Japanese locations). But endemic species are like the greasy diner down the street, in a sweaty old building, managed by the same old, sweaty, greasy bastard since the Kennedy administration; there are no “expansion” locations in the next town over, it exists in that one spot, it has for eons, and it will probably die in that same place.

Endemism is pretty common in isolated island chains, and elsewhere in the enormous expanse of the Pacific, you can find locations where endemic species make up large proportions of the total species found there. The Hawaiian Archipelago, with its many evolutionary radiations of endemic forest birds, fruit flies, and tree snails is a perfect example. In slightly less isolated places, a bit closer to the shores of Asia, Australia, or the Americas, you can still find unique species holding out on their itty-bitty island paradise homes, like the Yap flying fox, a species of fruit bat found on a single island in Micronesia, or the multiple Brachylophus iguana species endemic to Fiji and Tonga.

By looking at fossil remains and pollen records on the island, we know that when humans first set foot on Rapa Nui, the landscape was covered with a very different ecosystem compared to what exists today…and many of the players in it were endemic to the island, and most of them are now completely extinct. Many varieties of trees, shrubs, and grasses used to blanket the island. A major feature of Rapa Nui’s ecological aesthetic up until the middle of the 17th century were its palm forests. The largest and most visually dominant trees on Rapa Nui were the Rapa Nui palms (Paschalococos disperta), a variety of palm now considered to represent a species (and possibly a whole genus) that was found nowhere else in the world.

Rapa Nui palms were, as far as we can tell, most closely related to the Jubea palms found across the Eastern Pacific in a small region of central Chile. If the extinct Rapa Nui palms were anything like their closest kin, then they would have been an awe-inspiring sight for any traveler approaching the tiny outpost from shore. Jubea palms (also known as “Chilean wine palms”) can commonly reach heights of 80 feet or more (that’s about twice the height of a standard telephone pole), with trunks as wide as the business end of a Chevy Tahoe. These trees are the most massive palms in the world (although not the tallest; that honor goes to Columbia’s svelte Cocora wax palms, which look like honest-to-Christ Truffula trees IRL). It’s possible that the Jubea‘s island relatives were also this gargantuan, or perhaps even larger.


Rapa Nui of yesteryear may have looked much like this…well, excluding the gnarly dirt road on the left. ATVs weren’t really a thing on the island yet.

Rapa Nui’s puissant palms were undoubtedly a valuable asset to the people of the island, for everything from fuel, to crafting sea-faring vessels, to providing the raw materials for transporting moai hither and yon. Whatever reason was behind these mighty trees’ demise, the rest of island’s endemic inhabitants followed suit. Before the lush forests of the island evanesced, many species of bird, not known from anywhere else on Earth, flitted between the verdant towers. Fossil remains of unique, uncategorized varieties of heron, rail, crake, petrel, and parrot have been found on the island. We don’t know much about these bird species, other than that they were likely distinct from anything living anywhere else at the time. Rapa Nui also, up until only a handful of centuries ago, harbored seabird colonies of insane proportions, including many species of petrels and tern that are no longer found on the island. Given the diversity and estimated size of these seabird populations, Rapa Nui may have been host to the largest aggregations of migratory seabirds in the Pacific Ocean basin, if not the world. This, combined with the recherché assemblage of endemic birds, made Rapa Nui some kind of feathered Eden, the world’s greatest aviary, plopped in an almost preposterously isolated realm of the ocean.

Palm trees and birds are perhaps predictable inhabitants of extremely remote islands. Many palms tend to have large, buoyant seeds that can bob around on the ocean surface until they wash up hundreds (or even thousands) of miles away on some distant island. There are no shortage of species of bird that can travel exceptionally long distances on the wing, and even those that normally can’t, can hypothetically be blown around by strong storms. But some of the now-extinct endemic inhabitants of Rapa Nui have an origin story that is a little harder to imagine. Rapa Nui used to be home to at least several species of endemic land snail. Snails, as you may be aware, are not known for their athletic prowess or peripatetic nature. When it comes to scale and rate of movement, snails rank just above “dog turd on a tilted sheet of wax paper” and “pre-Thanksgiving airport TSA checkpoint line.” Oh, and when it comes to oceanic islands, there’s a big, wet, deadly obstacle in the way too…one that should be obvious if you’ve ever been sadistic enough to give the bothersome mollusks in your garden the ol’ “briney baptism”, the “haline how-do-you-do.”


Hint: It rhymes with “malt daughter”

Land snails, understandably, regard the sea as the The Puddle-Which-Can-Escargot-Fuck-Itself, and give it the widest of berths. Many other organisms that don’t have the best sea legs manage to get to far flung islands accidentally by “rafting”, often via being trapped on vegetative storm debris that drifts out into the open ocean, carrying them along with the currents as unhappy and exceptionally confused stowaways. But, given that land snails would wrinkle faster than Walter “Poor Chooser” Donovan in Indiana Jones and the Last Crusade on such a splash-prone liveaboard, other options are more probable. Very small species are light enough to be tossed high into the atmosphere by powerful storms as “aerial plankton”, possibly allowing them to rain down far offshore (indeed, many endemic island snails are incredibly tiny). They may also hitch a ride on birds by suctioning onto their legs.

However they did it, the ancestors of the itty-bitty land snails that once lazily slid across the foliage of Rapa Nui crossed stupid-huge distances of unbroken ocean. The phenomenon of thalassophobic land snails somewhat paradoxically living the island life is by no means limited to Rapa Nui. Endemic land snails (both prehistorically and currently) are scattered all over the Pacific, and one place where their diversity is/was off the charts is the Hawaiian Archipelago, arguably the only region of the Pacific that comes close to the remoteness of Rapa Nui. I say “was” because the endemic land snails of Hawai’i, many of which are the diminutive, jewel-like category of rainforest-dwelling “tree snails” or “kāhuli”, are mostly extinct. At one time, there may have been over 700 fucking species of land snail sprinkled across the island chain, but an estimated 90% or more of those species are now gone forever, with the majority of the remaining species threatened or endangered with extinction. For example, the remaining 41 species kāhuli on my home island, O’ahu, are ALL threatened with extinction, with many species only numbering a few hundred individuals. For some comparison to better understand this loss of biodiversity, the post-human colonization drop in species of Hawaiian land snails is roughly equivalent to the global count for living salamander species. Yes, the number of every single salamander species on Earth = the number of recently extinct Hawaiian land snail species. It’s also more than the total number of species of hoofed mammal on the planet. Apparently, the only fast thing these snails can do is go extinct.

The cause of this localized, ongoing snail mass extinction in Hawai’i, as well as on Rapa Nui, almost certainly has its roots in initial human colonization (and the invasive rats that came along with it), development and invasive plant-driven habitat loss, and more recent introductions of harmful species (like the rosy wolfsnail, which is a cannibalistic, snail-munching scourge of O’ahu tree snails). With the fall of the native forest habitat on Rapa Nui, so went the endemic land snails that depended upon it for food and shelter.

Today on Rapa Nui, much of the landscape is completely dominated by non-native plants and animals. Introduced bulrushes (Scirpus), native to South America, blanket the bottom of Rano Rakau crater. Stipus, Sporobolus, and Nasella grasses…all introduced…cover much of the exposed regions of the island. Trees do exist on the island, but they are aliens, like the paper mulberry (Broussonetia papyrifera), a native of East Asia. Introduced sweet potatoes, bananas, and sugar cane also grow along the rolling, windy slopes. These too are an immigrant assembly. The diversity of fauna on the island in modern times is depressingly low. A handful of introduced terrestrial birds, a few seabird species, a couple native butterflies, a non-native lizard here and there, and rats. And humans. And that’s about it. It’s less “island paradise” and more “a zoo fifty years after a global nuclear holocaust.”

Precious few endemic species have survived into the modern era. Among them are a handful of…ferns…I guess.


WOOOOHOOOO FERNS!!!

All of the endemic trees of Rapa Nui have gone extinct, leaving behind only small, scrappy, low-growing plants…except for a single species. The last remaining trees of the long-gone forests of Rapa Nui are the toromiro (Sophora toromiro). Unfortunately, although they have technically escaped extinction, you won’t find enclaves of toromiro growing on the island today. This is because all surviving plants (a pitiful handful compared to pre-deforestation numbers) reside in captivity, mostly in European botanical gardens, and with many of them all descended from the seeds of a single tree collected by Norwegian trans-Pacific, raft-voyaging (and kind of really, REALLY fucking racistnot even kidding) 20th-century explorer and ethnographer, Thor Heyerdahl, when he made a pit stop there on the island in the 60s.

Sophora are a group of small trees and shrubs that share the pea family (Fabaceae) with plants like acacias and lupines. The fifty or so species of Sophora are found scattered predominantly across parts of Eurasia, the western coasts of the Americas, the Caribbean, Australasia, and, notably, throughout many islands of Oceania…a feat of colonization likely afforded by their buoyant, salt-tolerant seed pods. Toromiro, like almost all members of the Sophora genus, have abundant, golden, billowing flowers that look like someone took many hundreds of miniature versions of Belle’s famous dress from The Beauty and the Beast and tacked them onto the plant.


As for the miniature Belles…so many dead….so many dead for the vanity of but a single plant…

Toromiro was the only tree known from Rapa Nui in historical times, and was still present in small stands on the island when Europeans first visited and gave their accounts. The plant has been extinct in the wild for nearly sixty years, and there isn’t much remaining knowledge of the ecology of the plant, or many of the details of its former use by the Rapanui in building and carving. However, there are other closely-related species of Sophora in regions either near Rapa Nui in geography (there are plenty of species in nearby mainland Chile), ecology, or culture, and from them we might be able to learn some clues. There are a number Sophora species native to New Zealand (Aotearoa), where they are known as kōwhai to the Māori people. Kōwhai were traditionally harvested for their strong, incredibly flexible wood for building material, and the flowers were used to create yellow dye. The nectar of the flowers is particularly valued by endemic birds like wood pigeons and tui. In Hawai’i, the endemic māmane (Sophora chrysophylla), grows in varied habitats on most of the main, high islands as either a shrub or a tree reaching well over forty feet in height. These days, most plants are found on upper slopes of East Maui’s volcano (Haleakala), or in a subalpine belt along the wide, grassy plains of Mauna Kea on the Big Island.


In a landscape that looks exactly like this, come to think of it (māmane pictured in the foreground)…
Photo: Jake Buehler

Like the kōwhai, māmane were traditionally used as tough building material, and as the wood components of tools subjected to great amounts of force (like handles for adzes, or farm spades). This ruggedness of the wood was also useful in construction of sleds for he’e hōlua…a favored sport of the Native Hawaiian aristocracy. A sport, mind you, that involved hurling oneself down a lava flow with nothing between you and the human-mulching quality lava rock develops at freeway-appropriate velocities but a narrow sled and a track made of oiled reeds. It had all the badass speed, danger, and excitement of luge…but situated on a landscape as forgiving as a sandpaper cheese grater. The māmane’s yellow flowers were also used to make leis and had astringent properties. Many portions of Sophora plants, including the seeds, are fairly toxic, so few animals or humans consume them (with the exception of the palila (Loxioides bailleui), a Hawaiian endemic, endangered, finch-like honeycreeper that has managed to preferentially subsist upon, and detoxify, the immature seeds of the māmane).

At one time, toromiro, too, many have been an important, keystone forest plant that now-extinct endemic birds would have depended upon for shelter or food. But, tragically, we will likely never know the role toromiro played in the Rapa Nui subtropical forest ecosystem. Efforts to reintroduce the existing plants back into the wild on the island are ongoing, but some obstacles include a severe lack of remaining total genetic diversity in the species (a phenomenon in population biology known as a “genetic bottleneck”), as well as, you know, the fact that every square foot of the goddamn island is currently choked out by invasive plants. That said, the toromiro is one of the few successful instances of a plant’s avoidance of extinction being directly the result of the cultivation of individuals in a “greenhouse zoo.”

As for the remaining terrestrial, endemic animal life on Rapa Nui, everything bigger than your thumb is almost guaranteed to be extinct, which is a huge bummer for people that are fans of halfway charismatic critters like birds. Or lizards. Or even a hefty bug or two. Rapa Nui has been scraped clean of anything like that in the ‘endemic’ column, but there may be a number of species still holding onto life deep in the subterranean maze that twists itself through the loose, porous volcanic rock of the island. Just last year, scientists discovered five new cave-adapted species of springtail (tiny, insect-like creatures) in caves near the village of Hanga Roa. Several years ago, a new species of booklouse (a variety of primitive insect) was discovered in a cave on the island. These are all putative endemic species of arthropod, barring any eventual discovery in other locations, of course. It appears as though they’ve waited out the ecological turmoil on the surface, hanging out as they always have, down into the safe, dark reaches of the cave, getting in touch with their inner Gollum for a century or three. If we continue to look down there, we might find other creatures unique to the island.


That, or a thousand, murmuring, menacing voices that your caving buddy doesn’t seem to be able to hear…..Jim? Jim? Where’d you go, Jim?!

On land, the vestiges of the endemic flora and fauna of Rapa Nui eek out an existence, never a moment away from being snuffed out by a competing horde of invasive species, or human meddling…but if you look under the crystal-clear waves along the island’s coastline, the story is very different. Rapa Nui’s waters, just barely warm enough at 27 degrees of latitude to support coral reefs, foster a wealth of endemic, marine fish and invertebrates. The level of endemism on Rapa Nui reefs is, on a proportional basis, among the highest in the world. For example, roughly 20% of all reef fish species on the island are found nowhere else in the world. The only place where this figure is greater is in the Hawaiian Archipelago, Rapa Nui’s only insular competitor for the title of “world’s most isolated”; there, the reef fish endemism rate is a bit closer to 25%.

The large chunk of the underwater biosphere in Rapa Nui that, by definition, stay close to home, make the reef ecosystem there quite literally one of a kind. Finding endemic organisms on islands is easy above the surface. Every damn diminutive dollop of land between East Asia and Hawai’i seems to have its own species of starling on it. Or fruit bat. Or Metrosideros plant. Even islands only separated from the nearest land by a few dozen miles can have unique, differing species found only there. Shit, even within the Hawaiian Archipelago, many “species” of endemic forest bird are actually complexes of multiple species, each one inhabiting its own island. The fragmentation of habitat that is a part of island life matters a hell of a lot to these organisms, and with geographic splintering comes insurmountable population splintering. But for the majority of coral reef organisms (and marine organisms in general), accessing far-away patches of habitat isn’t an issue. This is because while as adults, many marine organisms don’t move much from their reef home (or at all, if you’re a coral or a sponge), they can be transported a long ways as eggs or juveniles. A lot of these species are broadcast spawners, and start life as microscopic eggs drifting along in mid-water as plankton, potentially at the whim of currents like dandelion seeds blown by the wind. They eventually develop and come back to the bottom, but in that time period, they may have traveled hundreds of miles. Because of this, populations of marine organisms can stay connected for very long distances compared to their terrestrial counterparts, and with the relative absence of geographic barriers, the development of geographically-constrained species is a bit unlikely. This is why you can have things like completely different species of orangutan, water shrew, and leafbird (and many others) on either of the Indonesian islands of Borneo and Sumatra, for example, but the difference in reef-based species between the two islands is basically nil.

But, places like Rapa Nui and Hawai’i are so far away from other shallow water marine habitats that you can get populations of ocean organisms that evolve independently locally, because the nearest neighbors (or the larvae they send out into the world) are too far away to regularly breed with, or to be a continual source of migrants to the island. The end result are a bunch of species that either evolved there in isolation, or exist as the forgotten, lonely vestiges of once-widespread species that didn’t get the memo that their relatives went extinct everywhere else tens to hundreds of thousands of years ago.

Among Rapa Nui’s collection of endemic sea critters are several species of crustacean. One of them is the Easter Island slipper lobster (Scyllarides roggeveeni), found only locally around the rocky and coral reefs of the island. Slipper lobsters (family Scyllaridae) are so named due to their flattened bodies, wide-set eyes, and plate-like projections in front of their faces (actually modified antennae), making them shaped roughly like the relaxation footwear. Or perhaps like someone squashed a “regular” lobster underneath a slipper…not that anyone would voluntarily place their defenseless, piggly tootsies near something that looks like someone tried to grow a real-life Pokémon in a lab, but everything went horribly, indefensibly wrong.


“Pika….pi…ka…pi. *cough* Kill meeee. Kiiiilllll meeeeee!”

In stark contrast with the unavoidably threatened or extinct terrestrial endemics, we don’t really have a decent idea of the conservation status of the Easter Island slipper lobster. They are occasionally caught or speared for food, but since, at this point in time, they aren’t being shipped off-island in a large scale fishery, or consumed by tourists at the island’s smattering of restaurants by the boatload, there may not be too much to worry about, despite the species only existing on a single, minute island.

As for Rapa Nui’s endemic reef fishes, there are plenty worth mentioning. The exquisite video I’ve included below (originally found here), provides a wonderful tour of the towering coral gardens that hug the coastline, as well as a selection of the distinctive fish community that resides there:

By far the most ubiquitous fish on Rapa Nui reefs are the Easter Island butterflyfish (Chaetodon litus). Unlike the majority of their butterflyfish brethren elsewhere in the tropical Indo-Pacific, this species doesn’t have bright yellow, orange, and black-and-white striped coloration, instead going for conservative, almost business-minded gray and white tones. Indeed, they congregate in huge schools that migrate over the reef in a manner not dissimilar to gaggles of suited and well-coiffed disciples of business on their morning train to work.


It’s an e-fish-ient way to commute.

Another example is the halfbarred wrasse (Pseudolabrus semifasciatus), known to the Rapanui as “kotea hiva,” a fish only known to science from several specimens seen or collected at exceptionally deep parts of the near-shore environment. Other than its strange striping pattern (which makes it look like someone dabbed it with black paint, and let it drip down with gravity against the white background), we don’t know squat about the biology of this animal.


“Surf and Turf?” Try “surf and modern art.”

It has what are probably very close relatives in the genus Pseudolabrus found all over the South Pacific which might give some ecological clues. One of them, Pseudolabrus torotai, is found practically one door down in southeastern French Polynesia, and looks remarkably similar to the halfbarred wrasse.

Rapa Nui also has an endemic species of sharpnose (or “toby”) pufferfish (Canthigaster): the blue-belly toby (Canthigaster cyanetron).


I bet you can’t guess how this guy got his name.

There are scores more of these fish, each one a Rapa Nui original painted by evolutionary isolation, with some of them only known from a single collected individual. Cea’s scorpionfish (Rhinopias cea), the Rapanui filefish (Cantherhines rapanui), the Easter Island moray eel (Gymnothorax nasuta), and Randall’s chromis (Chromis randalli) are just a few of these endemic species. The last one in the short list above is named after the truly legendary ichthyologist Jack Randall, the scientist who was absolutely instrumental in kicking off comprehensive categorizations and descriptions of Rapa Nui’s endemic reef fish…an endeavor that has been, and continues to be, the subject of decades of tireless work.

The evolutionary laboratory that is the solitary island of lava rock known as Rapa Nui has had a tumultuous recent history, but also one that has had mixed ecological effect. The radical changes on the island’s surface have ultimately left the terrestrial environment nearly purged of any endemic life, but on the coral reef, endemic life is still quite abundant. Despite being an oft-referenced warning of the perils of extinction and ecological implosion, some of the pre-colonization diversity of the island remains. Today, it is promising to see efforts (albeit controversial ones) by local and national governments to preserve the current conditions of the island’s reefs by implementation of marine sanctuaries. Avoidance of what occurred on shore is imperative, given what we know now. The native and endemic players in this game are literally irreplaceable.

Image credits: Intro image (Rano Rakau crater), map of Polynesia, moai, Jubea palms, open ocean, fern, toromiro flowers, cave, slipper lobster, Easter Island butterflyfish, halfbarred wrasse, blue-belly toby puffer (John E. Randall)

© Jacob Buehler and “Shit You Didn’t Know About Biology”, 2012-2016. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Jacob Buehler and “Shit You Didn’t Know About Biology” with appropriate and specific direction to the original content.

Advertisements

One thought on “Easter Island: Ecoregion at the Edge of the World

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s