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Introducing the concept of native species

Are you a native of Colorado? By one interpretation of the term, no humans are native to Colorado.

Biologists consider flora and fauna to be either native or introduced (by humans). Native species are either indigenous, i.e., native but found elsewhere as well, or endemic, i.e., native and unique to the area.

Some of these thoughts on native species and island biology were spurred by a recent trip to New Zealand. New Zealand’s natural history would be expected to have strong similarities to that of Hawaii, considering both are fragile island ecosystems extremely vulnerable to the ravages of introduced species.



But there is one big difference: New Zealand was once continental as part of Gondwanaland, from which it separated 80 million years ago. It was already cloaked in vegetation when it got its start as an island system.

Hawaii, on the other hand, literally popped up in the middle of the ocean and had to start from scratch. Plants and animals had to happen upon the islands somehow and, perhaps even more daunting, find a habitat that suited them.



What developed on these islands are unique ecosystems where native plants and animals depend upon other native plants and animals for their survival.

On Maui, for example, the beautiful, endemic Haleakala silversword, a plant that sends up a 6-foot tall flowering spike at the end of its life, cannot survive without the endemic insects that pollenize its flowers.

In New Zealand, in a relationship that only a biologist could appreciate, the survival of certain native moth species is dependent on parasitization of indigenous mistletoes, themselves parasites of endemic plants.

But, as native Americans died from white man’s diseases, the islands are suffering at the hands (or mouths, or roots) of introduced species.

In Hawaii, biologists are concerned that predation of the silversword’s pollinators by introduced insects such as the Argentine ant is a serious threat to the plants’ survival.

In New Zealand, the brush-tailed possum, introduced from Australia, eats mistletoe, and introduced rats and stoats (what we would call ermines) eat endemic birds that spread mistletoe seeds, all threatening the existence of the moths.

The parasitism of endemic plants by indigenous mistletoes is an evolutionary relationship that is part of the natural balance. The New Zealand Department of Conservation goes to great lengths to protect mistletoe species. In other words, it’s OK for native species to beat up on native species.

Yet the very definition of “native” is slippery. The concept of introduced species clearly separates man from nature. Are aboriginal people more native than modern man? Could it be said that native Americans are just another species “introduced by man”?

Biologists in Hawaii distinguish a subcategory of non-native species: Polynesian introductions. While at first glance this seems to indicate that introductions by Polynesians are a lesser evil, it’s probably just a reflection of biologists trying to be as precise as possible about when species arrived on the islands.

New Zealand biologists, we were told, consider a species native only if it arrived before 1840, which was when the whalers first arrived and lived in New Zealand. This suggests that any species the Maori (New Zealand’s “native” people) brought with them when they colonized the islands are considered native.

This deadline would explain why, on a wildlife tour, our guide described a bird species as having “introduced itself from Australia,” some no-man’s-land between native and introduced. It flew or was blown over after 1840. If it had done so prior to then, it would be a full-fledged native bird.

To be a “native” Coloradan, all you have to do is be born here. The same can’t be said for strawberry guava in Hawaii or Russell lupine in New Zealand; though they’re “born” there, they’ll never be native.


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