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Theme 10: Invasions and extinctions

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Chicago, Seeking Lost Glory, Hunts for a Plant Last Seen in 1916. Invasive Species: Himalayan Balsam. Invasive Species Aren’t Always Unwanted. Photo are bad news, or so goes the conventional wisdom, encouraged by persistent warnings from biologists about the dangers of foreign animals and plants moving into new territories.

Invasive Species Aren’t Always Unwanted

Conservation organizations bill alien species as the foremost threat to native wildlife. Cities rip out exotic trees and shrubs in favor of indigenous varieties. And governments spend millions on efforts to head off or eradicate biological invaders. “I think the dominant paradigm in the field is still a ‘when in doubt, kill them’ sort of attitude,” said Dov Sax, an associate professor of ecology and evolutionary biology at Brown University.

But a growing number of scientists are challenging this view, arguing that not all invasive species are destructive; some, they contend, are even beneficial. Continue reading the main story “We’re actually moving plants and animals around the world all the time,” he said. Dr. Some alien species are undeniably harmful, a fact that neither Dr. Continue reading the main story. Mdinvasivebrochure. In Pieces - 30 Endangered Species, 30 Pieces. Dandelion: a useful weed? Common dandelion (Taraxacum officinale).

Dandelion: a useful weed?

Image by Franz Eugen Köhler, Köhler’s Medizinal-Pflanzen (public domain). I have recently moved house and I now have a small garden to take care of. I’m pretty excited by this prospect and have been trying to decide what to try and grow in in it. However, my little garden is currently somewhat overgrown with weeds—most of which are dandelions. The common dandelion (Taraxacum officinale) belongs to the Daisy family (Compositae/Asteraceae) of flowering plants alongside more popular garden plants such as sunflowers. A common cause of frustration to gardeners, the common dandelion has several features that enable it to be a vigorous weed in most types of soil. When I was a child growing up in London, there was a house near me where, rumour had it, a hermit lived by eating the dandelions growing in his back garden.

The common dandelion has other useful qualities. Common dandelions in bloom in my garden (Norfolk, UK) References: Like this: Like Loading... Invasives. NY: OUR WEEDS. Welcome to the weed atlas!


The Weed Atlas compiled here is hardly complete and subject to review and update. I'm including those weeds that I find here in New York City -in yards, in the cracks of sidewalks, in parks, on piers. NYC enjoys most of the weeds common to eastern North America, so that if you find yourself here and the weed you are trying to identify is in, say Clearfield, PA or Springfield, MA, the atlas may still be of use to you. Many of us get online now when we want to identify something, and that is no less true for the weeds in our yards. For years I depended on the book Northwest Weeds as my weed ID source because no proper book had been published for the Northeast. Deciding what is a weed and what is not is a fool's errand. The atlas follows in alphabetical order, with the botanical name first when I can accurately state it. Non-Native Plants Widespread, Plenty of Space to Invade. A new study, the first comprehensive assessment of native vs. non-native plant distribution in the continental United States, finds non-native plant species are much more widespread than natives, a finding that lead author Bethany Bradley at the University of Massachusetts Amherst called "very surprising.

Non-Native Plants Widespread, Plenty of Space to Invade

" "Ecologists typically think of invasive species as being introduced in one spot and gradually spreading out from there. But, we found that even species with only a handful of occurrences were distributed all across the U.S. ," she says. "The future may already be here. " As she explains, one of the major challenges for figuring out how species ranges could shift with climate change is that "we do not have a good handle on the factors limiting species' current distributions. For non-native, invasive species in particular, predicting invasion risk is difficult because those species that have recently arrived may not have yet spread into all the environments where they could get a toehold.