Tuesday, August 31, 2010

More about worms - fishing for answers

I recently wrote a post about the wonders of earthworms in a garden.

While working on the post, I was going to mention how I sometimes get earthworms for my garden.

Every now and then if I accompany my husband to a bait shop, I buy a small bucket of worms and take them home and drop them in my soil. I’ve been told that isn’t really a good idea and that they will die there. But since they would have died as bait on the end of some fisherman’s line, I figured dying in a pile of nice moist compost in my yard might be just as acceptable an end for these “sacred” creatures as being strung on a hook and chomped in half by a hungry fish.

But in my continuing effort to learn the correct “environmentally friendly” way of doing things, I wanted to check with a "worm expert" before I recommended this method. What I found out was that the harm that I was doing might not be to the worms, themselves, but to the environment because I was introducing a non-native species.

I contacted Tami S. Ransom, a Ph.D. candidate at the University of Virginia who has done some research on introduced species.

Here is what she said.

Hi Betsy. I saw that you had already posted your blog about adding earthworms to gardens. The only thing I wanted to bring to your attention is that all of the earthworms that you buy as bait or for compost piles are invasive earthworms. In urbanized areas, such as the target area for your blog, invasive earthworms are already well-established. Pretty much any earthworm that you find in your garden is a non-native earthworm. And, it is true that these non-native earthworms can be beneficial for gardens.  

However, if you post a follow up to your original post, you should caution your readers that if they decide to purchase earthworms for their gardens, they should avoid purchasing "Alabama jumpers". These earthworms in the genus Amynthas have been recently introduced from Asia. Because they are recent invaders, data about their effects is still scarce. However, it does appear that they can damage forest ecosystems. When introduced here in the South, they seem to thrive. I've seen riparian areas here in Charlottesville where it appears they are denuding areas of leaf litter and reducing the understory plant community. 

Here's a link to a recent story about these Asian earthworms: 

As I said, in urban areas, it's probably not too big of a deal to put purchased worms in gardens (as long as they aren't those Asian ones!) The European invasives are already here to stay. All the compost worms that people buy are also invasives. But, if you are trying to be eco-conscious, then making your already established worms happy is probably the best way to go :)

Thank you Tami. As always, I appreciate all the wonderful scientists and scholars who are willing to help us all learn the right way to "take care of our share" of the planet!

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