Blog reader Shawn sent this link to me yesterday. It’s a pretty short take on a complex topic, but even so I was troubled by the perception that all nuisance weed species are our own fault.
Sure, it’s true that humans have moved plants or plant parts around with them for centuries. Sometimes it’s been deliberate, and sometimes it’s been accidental. But other animals also move plants around, especially seeds. When we draw this kind of distinction between what we do and what other animals do, philosophically we are removing ourselves from the natural world. True, we have technology and all kinds of other human inventions, but as a species we are still part of the biosphere.
Ivy’s little dispersal units – spread by birds
Philosophical issues aside, there’s another part of this blithe acceptance of weedy species that concerns me. Though plants take advantage of animals as a means of dispersal, the rate at which nonnative, weedy species are spreading and colonizing new environments is unprecedented (this is where technology comes in). Ecosystems can adapt to new species and other environmental challenges – but when the rate is accelerated, the adaptive process is impaired. Thus, some native species go extinct when the rate of change is too great.
Ivy left to its own devices in a natural area
These are basic ecological concepts – and we ignore them at our own peril.
Ecosystems can adapt to new species and other environmental challenges – but when the rate is accelerated, the adaptive process is impaired. Thus, some native species go extinct when the rate of change is too great.
Someone more learned than me has been quoted as saying:
On an island, when you have an invasive species, you can drive a plant right to the edge and then off that edge. But the continental United States is pretty big, with a whole bunch of different ecosystems – in other words, places for plants being infringed upon to escape to. Now, Dr Davis did not say, and nobody believes, that invasives can’t infringe on a native plant’s growing range so that where it once covered 100 acres, for example, it now covers one. But in terms of making a plant go extinct? It hasn’t happened.
Please discuss.
Ecosystems can adapt to new species and other environmental challenges – but when the rate is accelerated, the adaptive process is impaired. Thus, some native species go extinct when the rate of change is too great.
On an island, when you have an invasive species, you can drive a plant right to the edge and then off that edge. But the continental United States is pretty big, with a whole bunch of different ecosystems – in other words, places for plants being infringed upon to escape to. Now, Dr Davis did not say, and nobody believes, that invasives can’t infringe on a native plant’s growing range so that where it once covered 100 acres, for example, it now covers one. But in terms of making a plant go extinct? It hasn’t happened.