Hawaii Kua Uli -- Grand Tour of Hawaiian Ecosystems

HAWAI‘I KUA ULIH A W A I ‘ I T H E V E R D A N T B A C K

HAWAIʻI KUA ULI H A W A I ʻ I T H E V E R D A N T B A C K

S. M. GON III, Ph.D.

Honolulu, Hawaiʻi

The native plants, animals and ecosystems of Hawai‘i form a unique biogeographic province rich enough to include representatives of all the global biomes except tundra.

This island ecoregion’s history of change has taken it through...

a period of habitation by an island people who developed a culture as rich and unique as their natural setting

and whose lifestyles began a course of ecosystem change...

that today culminate in huge challengesto native species & ecosystems and to those charged to manage them

The Hawaiian Islands are the most isolated high islands on Earth

Niʻihau

Kauaʻi

Molokaʻi

OʻahuLānaʻi

Kahoʻolawe

Maui Hawaiʻi

2500 miles or more separates Hawaiʻi from surrounding continents

Without the help of people, only those animals who could brave a trans-oceanic voyage by air or waves were among the colonizers.

Here they developed into species like none other on the planet; coadapted and balanced...

While the ʻiʻiwi receives a nectar meal… ►

◄ The plant’s anthers deposit pollen precisely on its head

…as the curved bill of the ʻiʻiwi is a match for the tubular flowers of the koliʻi, a native lobelioid...

About 90% of the roughly 1200 species of native Hawaiian plants are entirely restricted to the Hawaiian Islands.

Some, like the ‘āhinahina of Haleakalā, are found only on a single island, a single mountain, a single region of the mountain.

And the proliferation of bird species, such as these Hawaiian honeycreepers, from a single ancestor, put the celebrated finches of the Galapagos to shame.

◄◄◄ (miserable little lab Drosophila)

◄◄◄ Gigantic, picture-wingedHawaiian pomace flyOne of 800+ Hawaiian species

Terrestrial Hawaiian ecosystems have been called systems of birds and invertebrates…

endemismReef fish24%

endemismReef fish52%

65%

32%Overall marine invertebrates average an endemism rate of

29%18% 49%

47%

49%40%

The ecological amplitude of the Hawaiian Archipelagodistinguishes it as a World Biogeographic Province

Topography ranges from uneroded youthful lava landscapes…

To razor-back ridges the end product of millions of years of erosion...

From lands that were created just this morning...

barren and devoid of life...

To climax forest supporting thousands of species...

From subalpine cinderlands as dry as any of the world’s deserts...

…to arguably the wettest spot on earth, at Waiʻaleʻale...

From coastal dunes at sea level...

To snow-capped volcanic summits just shy of 14,000 feet...

So let’s begin our tour of Hawaiian ecosystems, from coast to summit, and from stream to sea...

The coastlines of Hawaiʻi are generally sunny and dry; dunes of coral sands or rough lava cliffs create a challenging landscape...

COASTAL ECOSYSTEMS

But native shrublands, built of plants such as these hinahina, beach heliotropes, stabilize and clothe the dunes

In a square meter of rich coastal vegetation can be found ʻāweoweo, ʻōhelo kai, ʻākulikuli, kākonakona, and hinahina.

One very special coastal forest is found only on the islet called Huelo Rock, off the sea cliffs of Molokaʻi.

A stand of native coastal loulu palms occupies the top of the islet. Rats have all but eliminated it from the seacliffs, where it probably once dominated.

Forbes, a botanist visiting Hawaiʻi in the 1800s, documented some Hawaiians climbing the 100 foot precipice of Huelo, then, holding the large fan-like fronds of the loulu palms, leaping off the top, and gliding (steeply!) into the churning ocean -- just for fun!

Another coastal forest type of great significance is hala forest, found on all the main islands. Naupaka is a typical understory plant here.

Plants are only one element of the coastal ecosystems. There are many animals that call the coasts home, such as the Hawaiian Monk Seal, called ʻīlio kai, dog of the sea.

Sandy beaches are the required nesting sites for sea turtles such as honu.

Such animals are revered by many Hawaiian families as ʻaumākua

In the ancient past, seabird nesting colonies were not relegated to offshore islets, but extensively covered the main islands.

One unusual coastal system found between the land and the sea is anchialine pools

Endemic red shrimp ʻōpaeʻula are the major life forms, with other invertebrates and algae that thrive best in a fish-free environment.

In a tradewind setting, the leeward flanks are usually dry, yet such areas, receiving less than 10 inches of rainfall a year, may lie only 5 miles from rainforested summits receiving over 200 inches annual rainfall.

LOWLAND ECOSYSTEMS

Grasslands, shrublands, and summer-deciduous forests of native trees such as these wiliwili were widespread in the dry lowlands of ancient Hawaiʻi.

Pua ka wiliwili nanahu ka manō

Other trees, such as ʻohe makai, share an open woodland with wiliwili on sun-baked lava plains.

Kukulu aeʻo

On geologically young islands, lava flows support pioneer lowland dry forest dominated by ʻōhiʻa lehua, despite almost no soil development.

Where it is too dry for trees, mixed shrublands of hardy species such as ʻaʻaliʻi and pūkiawe cover the land.

Dry leeward lowlands supported extensive pili grasslands.

Dryland forms of ʻakoko, a milky-sapped euphorb, lend a softer texture to a rough lava landscape.

Dwarf-shrublands, such as this one of ʻilima, form a colorful carpet in many coastal and lowland areas in Hawaiʻi.

Bright flags of color mark the ʻōhai, which grows from sea level to about 500 feet above, pollinated by native bees.

The lowlands are also where the majority of iliahi (sandalwood) grows. It is one of the many tree species that can be found in the diverse Hawaiian mesic forests.

In fact, there are more species of native trees found in lowland dry and mesic area in Hawai‘i than in wet ones.

The Hawaiian poppy, called pua kala (thorny flower) because of the sharp spines at the tips of the leaves, thrives in some of the most dry and desolate areas near sea level.

The bright yellow flower of the Hawaiian cotton, maʻo, marked some of the driest native shrublands just above the coast on Oʻahu, Maui, Molokaʻi, Lānaʻi, and Kahoʻolawe.

The pueo, important ʻaumakua to many Hawaiians, is a bird of prey that thrives in the drier lowlands.

Although the nēnē goose is now largely relegated to marginal subalpine habitats on Hawai‘i and Maui, its prehistoric habitat was in the warmer lowlands.

The fossil record indicates that a giant flightless goose was once a formidable presence in the lowland forests of Hawai‘i.

The ʻelepaio is an ideal signature bird of lowland forest, greeting human visitors with great curiosity...

The ‘amakihi is perhaps the most common native forest bird remaining in our lowland mesic forests...

ʻŌpeʻapeʻa, the Hawaiian bat

The membrane spread between the wings of a bat, are very much like full sails (peʻa) spread between the masts and spars of a voyaging canoe.

In the rainforests of ancient Hawaiʻi, lush, moss-covered branches rose to closed canopies, providing protection to more delicate ferns, shrubs and plants beneath. MONTANE

ECOSYSTEMS These wet systems dominated, as they do today, on the wet, wind-ward flanks and summits of the higher islands, where cloud and/or rain is a daily occurrence.

In mesic and dry forest, tree diversity is highest, but in the montane wet forest, overall plant diversity is highest, with many hundreds of species of herbs, shrubs, vines, and ferns.

This lush mix of giant ʻapeʻape, lobeliads, and ferns lines the wet gulches running through the montane forest of East Maui.

Our only native carnivorous plant is a delicate sundew that grows in the montane bogs of the island of Kauaʻi.

The rich red fruit of the ʻākala (Hawaiian raspberry) catch the eye …

A delicate Cyrtandra, was aptly called by Hawaiians haʻiwale (broken easily). They can persist only in pristine, pig-free wet forest, a habitat only rarely encountered today.

The montane forests of the wao akua were considered off-limits and dangerous for people in ancient Hawai‘i.

Only small parties led by specialists with knowledge of the forest and its resources could enter, and only after rigorous and ceremonial entrance protocols.

On steep cliffs at the heads and walls of wet valleys, a rich mix of ferns and shrubs hold erosion in check and provide for an essential watershed.

ʻIeʻie vines climb the trunks of wet forest trees, offering clusters of fruit for birds such as the ʻōʻū. Its long aerial roots provided the woven framework for sturdy feathered helmets (mahiole).

Red ʻōhelo berries provide food for nēnē goose, ʻomaʻo thrush, and other native birds that forage through openings in wet forest.

The ʻōhiʻa lehua tree is the dominant species in Hawaiian wet forest of all islands.

Its nectar-rich flowers provide the mainstay for

Hawaiian honeycreepers, such as this ʻapapane.

The ʻōhiʻa is dominant tree of the sacred upland realm of the gods

The Maui parrotbill is actually a honeycreeper with a bill specialized for snapping through twigs in search of grubs.

‘I‘iwi shot

The ʻiʻiwi is one of the scarlet honeycreepers, whose brilliant feathers were worked into symbols of highest rank.

The Hawaiian happyface spider spends its entire life under the protective cover of a sturdy leaf

The Kamehameha butterfly is one of only two native butterflies in the Hawaiian fauna.

Pūpū kuahiwi or kāhuli, Hawaiian tree snails, feed on algae and molds that grow on the leaves of wet forest plants.

Two male Hammer-headed Hawaiian flies battlefor mating territory on a branch of an ʻōlapa tree.

Above about 6000 feet, the tropical inversion layer limits the formation of clouds, and we pass from the wet montane zone into the much drier subalpine and alpine ecosystems above them.

▲SUBALPINE & ALPINE

ECOSYSTEMS

Again separated from moisture, set above the average cloud tops, the subalpine zone mimics the dry lowland zone, and includes many of the same species.

It can be extremely hot by day without the protection of clouds, and at night, temperatures can plunge well below freezing.

But once the challenges of the high-elevation environment are dealt with, adapted species are free to thrive and proliferate

Hawaiian honeycreepers have, even here, found a niche. The palila is a seed-eater that depends on the subalpine māmane forest for survival.

Highabove the

vegetation limitsis a snowy alpine zone

seemingly devoid of living things

The wekiu bug (named for the summit of Mauna Kea), is flightless and dark to absorb the sun’s warmth in the icy desert setting.

Running through the different zones to the sea are freshwater streams that provide habitat for endemic Hawaiian freshwater species.

ʻŌpae kalaʻole are endemic Hawaiian

stream shrimp whose ancestors lived in the

surrounding sea

.

AQUATIC ECOSYSTEMS

▼

Native gobies, such as the ʻoʻopu alamoʻo, moved from marine habitats into Hawaiian streams. They still send eggs downstream, which hatch and undergo larval development as marine plankton before they return upstream to mature.

Our Hawaiian stream nerite snail,hīhīwai, lays eggs on stream boulders, but snail hatchlings are washed down

to the sea, and need to crawl slowlyback upstream as they grow.

Many species of delicate Hawaiian damselflies, pinao ‘ula, grace the streams of different islands. Their

young are aquatic predators, while as adults they catch small airborne

insects in wet forest.

Streams and wetlands provide habitat for waterbirds, such as the Hawaiian coot, ʻalae keʻokeʻo, and the Hawaiian duck, kōloa maoli.

The Hawaiian gallinule, ʻalae ʻula, figures prominently in story and legend

MARINE ECOSYSTEMSstreams connect the land with

ROCKY INTERTIDAL

NEARSHORE SANDY

CORAL REEF

PELAGIC

Subterranean ecosystems lie under it all, whether coastal lava plain, montane wet forest, or alpine desert, the volcanic foundation of the islands is rich in caves: lava tubes formed in pāhoehoe flows.

Here, a skylight in the roof of such a cave sends light into an otherwise lightless world, and roots of ʻōhiʻa growing above reach down for moisture.

Those roots form the basis for surprising Hawaiian cave ecosystems. They bring nutrients from the sunlit surface into an otherwise sterile environment.

SUBTERRANEAN ECOSYSTEMS

Eyeless, nearly-pigmentless cave crickets wander through the root mats, feeding on decomposing plant matter. They have close relatives that live in the forests above, indicating the course of evolution: an adaptive invasion of a new niche where light was no longer important.

The cave crickets may have escaped their original predators, such as birds, but some predators followed them. This spider belongs to a group sometimes called “big-eyed hunting spiders,” but here they have become small-eyed big-eyed hunting spiders. On Kaua‘i, where cave systems have had the longest time to evolve, the evolution has culminated in a “no-eyed big-eyed hunting spider” that is amazingly bizarre.

So these were the native ecosystems of ancient Hawai‘i: nearly 250 different kinds of natural communities from coast to alpine summit, including vegetated, aquatic, marine, and subterranean ecosystems.

In our times, we have seen many changes to these systems, and great challenges to their conservation.

They are unique life forms found nowhere else in the world

Hawaiian species and ecosystems deserve our care because:

Hawaiian species and ecosystems deserve our care because:

They comprise the foundation of native Hawaiian culture.

mahalo!(merci!)