Hawaii is home to volcanoes and silverswords | ECOVIEWS

Mauna Loa has been trying for years to grab all the attention on Hawaii’s Big Island, its latest attempt this autumn being an eruption and magnificent lava flows. But Mauna Loa has another impressive natural feature, silversword plants, whose closest surviving relatives are found on the Haleakala volcano in Maui.

Of the diverse array of plants I saw when visiting the Hawaiian Islands, silverswords were one of the few native plants living in their natural habitat.

Most species of plants and animals in our southernmost state found a home there only in the last few centuries, and many were introduced to the islands by people ― sometimes intentionally, sometimes unwittingly. Any species found in Hawaii was once an immigrant or is the descendant of one.

The Hawaiian Islands represent an environmental marvel of oceanic landforms that rose from the sea as volcanoes. Any animal or plant in Hawaii had to have an ancestor that came from somewhere else. But species that arrived from a million to a few hundred years ago can now be considered native Hawaiian species.

The evolutionary process began soon after each species arrived. At least it did for those that survived long enough to begin changing. To survive, a species had to adapt to its new environment, which was undoubtedly different from its mainland origin. The slow but inexorable evolutionary process took many thousands of years for some species; for others, the changes occurred over millennia.

The silverswords I saw in Haleakala National Park were at an elevation almost 2 miles above sea level. Most plants that might compete with them and the animals that might eat them would find the environment inhospitable at best.

Silversword plants look to me like a basketball-size hedgehog with long, silver-coated spines. In the same family as dandelions, silverswords are a fine example of evolution. Imagine a dandelion or aster adjusting to a terrain of ancient lava substrate that supports sparse vegetation. Add cold temperatures, arid conditions, constant wind and intense year-round sunlight and you have the environment to which the silversword adapted. Grazing by cattle, pigs and goats led to near extinction of silverswords. Now the National Park Service does not let them eat the rare plants.

Polynesians arrived on the islands about 1,500 years ago. Hawaii has been shaped by human hands for so long that the mix of endemics and invaders, both plant and animal, is remarkable.

One day, over the span of just a few minutes, I saw free-living plants and animals from Indonesia, Madagascar and six continents. I also saw a couple of species that are considered native to Hawaii. For an ecologist, exploring the natural history of the Hawaiian Islands might be compared to window-shopping at a store in which merchandise from Walmart, Tiffany’s, Home Depot and Trader Joe’s is displayed randomly throughout the store. When you turn a corner, you have no idea what to expect in that aisle.

Certain introduced species, such as the predatory Indian mongoose, have had significant negative impact on the native fauna. The mongoose was an ill-advised introduction to the islands in the 1880s to protect the sugarcane industry from rats that were eating into the plantation owners’ profits. The plan went quickly awry as the mongoose found it was much easier to eat native birds and their eggs than to chase rats. These ferretlike carnivores still slink around on at least three of the larger islands.

Some animals not introduced by humans qualify as Hawaiian natives. Endangered green sea turtles and monk seals frequent some of the beaches. Rare Hawaiian geese walk around the tops of volcanoes where silverswords live.

Of Hawaii’s remaining flora and fauna, 90 to 95 percent (maybe more) are newcomers that have joined this unusual ecosystem in the last couple of centuries. Collectively, native and immigrant species make Hawaii a place of wonder for any botanist, zoologist or ecologist — and a beautiful vacation spot for anyone.

Whit Gibbons is professor of zoology and senior biologist at the University of Georgia’s Savannah River Ecology Laboratory. If you have an environmental question or comment, email ecoviews@gmail.com.

This article originally appeared on The Tuscaloosa News: Hawaii is home to volcanoes and silverswords | ECOVIEWS