Friday, June 27. 2014
wildbird in Chaparral Ecology
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When I sat down to write the Wikipedia page for Xylococcus bicolor, or Mission Manzanita, I really didn't know a whole lot about it. Yeah, it grows all over my yard and we have treasured them for many years, but you really learn what you don't know when you try to write about something! And you can also learn how much others don't know, either.* It turns out that Mission Manzanita, the only species in the Xylococcus genus, is pretty obscure. And one of the biggest mysteries is how it propagates itself.
It seems that "nobody" has seen a Xylococcus seedling. Not in nurseries and not in the wild. My wife and I think we found a seedling on our property a few years ago, but it is unconfirmed as of this time. These plants are not exactly rare within their limited range. So how do they come to exist? I sure doesn't bode well for the future of the species if they have for some reason become unable to propagate!
I found references to theories that the seeds need to pass through a grizzly bear in order for them to germinate. Well, I don't know about that. There haven't been grizzly bears on our property for a long time - longer than the lives of most of the manzanitas we've got. Others theorize that passing through a coyote or even a bird is required for germination. There are lots of coyotes and birds around, so where are the seedlings?
Well Lee Gordon is not one to just sit around and wonder, and Rick Halsey is not one to sit around at all. Lee set out to understand Xylococcus germination and he has made some great progress. He has managed to germinate some seeds! He has yet to figure out how nature prepares them, but he has proved that Xylococcus seeds are routinely viable. And he is working on understanding natural germination. You can read about his findings so far in these two papers which he has posted on the website of the San Diego chapter of the California Native Plant Society:
In the mean time, Rick Halsey and Robby Guy have been out in the field searching for seedlings. Last I heard they think they found a couple in Balboa Park, of all places. That is very promising. I don't know if they've found others since then or not. It can be deceptive whether a plant is a seedling or not because they can also re-sprout from the roots. So a plant which burned or was chopped off could put up a little stem that looks like a seedling, but isn't. If you think you have found a seedling where there was no previous plant, you should contact Rick and Robby through their organization, the Chaparral Institute.
And whatever you do, don't cut down or remove any Xylococcus bicolor / Mission Manzanita shrubs. They may be more precious that anything you could possibly plant or build in their place.* I wrote the article hoping that someone more knowledgeable would come along and add to it and make it more complete. Any takers out there?
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