Invasive species and native species

Here's a thought provoking question; what is a native species? When does it move far enough from where it is now, to where it goes to, to become a non-native species? This isn't a question from your biology class, it is a real quandary. For instance,  the goldspotted oak borer is an invasive species in Southern California, but its origin isn't that far off- Northern Mexico and parts of Arizona. I discussed this with reporter Clint Williams last week, to support his excellent article in Mother Nature News, Imported firewood can be more dangerous than fire. Crossing a major biological divide- like a huge desert- is just as potentially damaging as crossing the Atlantic or Pacific ocean, when it comes to the transport of pests.


This issue also came up in a recent email from the Don't Move Firewood advice line. So let's take a look at that!


Dear Don't Move Firewood,

Dandelion seeds are light and fluffy so they will blow long distances and spread. Burdocks cling to jeans and fur and are carried long distances to spread species. Transporting species from one region to another helps nature. The insects and the trees are both part of nature.




Dear Tom,

You are misunderstanding the issue at hand. Don't Move Firewood isn't because we are concerned that native, natural, local insects will be spread throughout their appropriate habitats. This isn't about creatures that belong in the landscape. This is about invasive species. Invasives are things that reproduce, damage, and even kill in an out of control fashion, because they do not belong. Insects and trees are part of nature, but these particular insects are NOT part of this nature. These insects and diseases belong in far off lands, or at least biologically separate lands, where they originally evolved. When people move them, they escape "nature" in the truest sense, and grow out of control. Transporting these species is destructive.

Thanks for reading.