Lessons from afar on how landscapes go bad

VIC LEIPZIG AND LOU MURRAY

Any normal couple could go to Maui and have a great time admiring the

tropical plants. Not us. We viewed Maui with the eyes of biologists

and were saddened by much of what we saw. Once we looked past the

lush beauty of the island, we saw an ecosystem in even worse shape

than our own and immediately began to draw parallels with our local

landscape.

We were stunned to find that rangers at Haleakala National Park on

Maui are fighting some of the same weed species that have invaded our

local habitat. On our drive to the summit of Haleakala, Maui’s

largest dormant volcano, we saw wild fennel, tree tobacco, and castor

bean growing in profusion. These three invasive species are causing

considerable environmental damage there, just as they are here.

Castor bean, a native of eastern Africa that is cultivated for

castor oil, gained a foothold here years ago. It took over a portion

of Shipley Nature Center and spread throughout Central Park.

Fortunately, we have the means to control castor bean locally. We

live in a town of 200,000 people with populous surrounding

communities. This large potential volunteer base has been invaluable

in controlling castor bean. By eliminating all mature plants and

pulling up all new seedlings as they sprout, the Friends of Shipley

Nature Center have been able to prevent any castor bean plants from

setting seed since they took over management in 2002. Unfortunately,

the seeds survive in the soil for up to 10 years, so the Friends will

be fighting castor bean for many more years. But with many volunteers

in proportion to the weeds, there is a good chance of eliminating

castor bean from Central Park.

The rangers at Haleakala are not as fortunate. The population of

Maui is about 100,000. They have far more acreage covered with

invasives and far fewer potential volunteers. They may never be able

to eliminate castor bean.

Wild fennel and tree tobacco were two other weeds that we saw on

Haleakala. Both are from Mexico and have invaded our local wild lands

as well. Of the two, wild fennel is more detrimental to the

environment. If you drive to San Diego, you will see wild fennel

overgrowing the coastal sage scrub at Camp Pendleton.

As invasive weeds spread, they overtake native plants. Local

wildlife usually is not adapted to utilizing these new species. The

result is that endemic plant species are crowded out, and endemic

wildlife that depends on them can decline or even die out.

It took a million years to establish Hawaii’s island ecology with

its unique flora and fauna. On the average, one new species of

insect, plant, or animal took hold there every 10,000 to 35,000 years, arriving by wind, wave or wing. When the Polynesians first

arrived about 1,600 years ago, they brought domestic plants and

animals with them, initiating environmental degradation.

When European seafarers arrived in the late 1700s, the native

Hawaiian ecosystem went into a more rapid decline with the

introduction of many new invasive species. A similar phenomenon was

happening here in southern California with the arrival of the

Spaniards as wild lands were converted to rangeland and exotics such

as mustard were introduced.

Trade between the Hawaiian Islands and Mexico was responsible for

the introduction of the first mosquitoes to Hawaii and provides an

excellent example of how a chance introduction of a new species can

change things forever. In 1827, natives on Maui began to complain

about itching bites from a small flying insect that they called

“singing in the ear.” A particular whaling vessel had docked there

the year before. Its sailors had last filled the ship’s water casks

on the western coast of Mexico. They inadvertently brought larvae of

the Southern house mosquito along with the water. When they emptied

their water casks into a stream prior to refilling them, they seeded

the area with mosquitoes, which quickly became established.

The Southern house mosquito is not just a nuisance to humans, but

also brings death to wildlife. This mosquito carries both bird pox

and avian malaria. These diseases have caused the deaths of many

birds in Hawaii at lower elevations where the mosquitoes thrive. With

global climate change, the mosquitoes will be able to move to higher

elevations. Thus the diseases that they carry will kill even more

birds and possibly cause extinctions. This is but one example of how

the inadvertent introduction of one tiny new species can cause

profound and long-lasting effects.

With the increasing popularity of air travel in the 1960s,

introduction of exotic species to Hawaii has increased to 20 new

species each year. While the specialized ecology of the islands makes

habitat degradation more obvious, the same thing is happening here.

Prior to restoration, Shipley Nature Center was 80% nonnative.

Our trip to Maui made us realize more than ever how fragile our

ecosystems are and how rapidly modern humans are changing the face of

the planet. Most of these changes bring no improvement to human

wellbeing and no benefit to the economy. They are pure loss with no

offsetting gain. They are not the price of consciously made

trade-offs. They are simply the result of human ignorance and

sloppiness. People should be ashamed for what has been done to Maui

and other troubled ecosystems.

* VIC LEIPZIG AND LOU MURRAY are Huntington Beach residents and

environmentalists. They can be reached at [email protected].