Often this column is used to promote the sustainability of native plantings and the price of introducing invasive non-natives. This is not done because one species of flora or fauna is better than another, but because biotic communities function within a delicate balance that has been centuries in the making.
As defined in the Executive order on Invasive species, signed by President Bill Clinton on February 3, 1999, an invasive alien species is one whose introduction is likely to cause economic or environmental harm with respect to a particular ecosystem. Although never even considered by Mr. Bill, this distinction could easily be applied to humans and their domestic animals. Rats, africanized bees, and white fly are also alien invaders.
One species, the Argentine ant (linepithema humile) is displacing native ant species to the point that the indigenous ants are becoming increasingly rare. Very common in coastal patches of Southern California, the invasive Argentine can now be found in a kitchen or bathroom near you. At my house, ant genocide has become a daily ritual, an ant Gallipoli if you will. Without a natural predator, this is truly about fighting off an invasion.
Discounting the mistakes of others, local agencies are farther harming the ecological balance by actively promoting the introduction of exotic species. The County Department of Agriculture recently announced it would cooperate in the release of pest-killing wasps. Glycaspis brimblecombei, a native of Australia, is being introduced to attack another Australian native, the parasitic red gum lerp psyllid, which is plaguing the Australian species,the red gum eucalyptus. What happens if the wasps gets out of control like its predecessors?
In a similar effort,the Carlsbad City Council voted to spend $106,000 this year on the rehabilitation, and $60,000 annually in future years, for the management of Hosp Grove. Over the next decade that amounts to $640,000. The city is working with the California Department of Forestry and Fire Protection to develop a rehabilitation and management plan, which could possibly involve the release of the predatory wasp to prey on the lerp psyllid. Eucalyptus trees not vulnerable to the red gum lerp psyllid will likely be planted to replace those removed as a result of the infestation. Why not just remove all the non-natives, there by removing the exotic pest,and the need for introducing a corresponding predator?
In San Diego County, eucalyptus trees have taken on a mythical status. This can be the only reason they are not seen as the invasive non-native they are. The Carlsbad City Council is willing to ignore all the evidence supporting the environmental restoration of native habitats, in favor of the misguided notion these tree belong there. They don't. This Australia species was introduced only as a money making scheme. Ironically the upkeep of Hosp grove is now coming at the tax payers expense.
Sooner or later Southern Californians must come to terms with the fact they live in Southern California. As easy as it may seem to replace one biotic community with another, reality is now proving the simple act of planting non-native trees to be a costly mistake. As the battle continues against these unwanted pest I can't help but wonder, "Is this how the indigenous tribes felt when the Spanish showed up?"