SciSun: The Ins and Outs   Leave a comment

The California Clapper Rail (Rallus longirostris obsoletus) is a federally-endangered, although relatively un-assuming, shorebird. It makes its living by searching in the mud and dense salty-marsh vegetation for snails and oysters and small crabs. After all, someone’s got to do it. (Interestingly, the Clapper Rail has never actually been known to clap. Maybe it’s never found anything it’s really excited about). For generations families of Clapper Rails have made their homes among Pickleweed (family Chenopodiaceae), and California Cordgrass (a native semi-aquatic grass). But the 1970’s introduction of the invasive species Salt marsh cordgrass (Spartina alterniflora) as a way to reclaim marshland is today leading to the potential extinction of native Cordgrass and what may be a permanent change to the natural ecosystem. The story of invasive species crowding out native plants and animals has been seen before and usually ends with unfortunate results to the natives. But in this case, despite loss of local California Cordgrass, the Clapper Rail doesn’t seem to care one way or the other.

When a non-native species is introduced into an environment the sequence of events, observed countless times, is the non-native has few or no enemies; the climate and environment is similar and favorable to the invasives’ home ecology; and the newly-introduced species might have enough advantages to out-compete and exploit this ‘new environment’, often either crowding out natives, or taking over resources until there’s nothing left for the local species which is displaced, to become rare or extinct. These invasive species can be quite the bullies. But not only are the native species affected; every plant and animal that depends upon the displaced species, as well as the environment itself, is usually effected. In time entire ecosystems can be altered and usually virtually impossible to recover.

'Hmm, that island of grass is somewhat interesting.  We are mildly amused.”

‘Hmm, that island of grass is somewhat interesting. We are mildly amused.”

But an interesting thing is happening with the Clapper Rail, and their cordgrass home: Over time, the Clappers seem to prefer, or at least have come to accept, the Salt Marsh cordgrass over the native California grass. (Yes, the two grasses may seem similar, but it makes a difference. Just like most of us would rather have chocolate milk, over low-fat white milk even though white is better for us). So if the birds are happy then everything is OK, right? The challenge comes when as a part of their responsibilities, government organizations like the Fish and Wildlife Service; university scientists and researchers; and environmental groups believe it’s their duty to remove all non-native, invasive species as a way to protect and preserve native species – particularly when those species are officially listed as protected. Which is fine when the non-natives are clearly unwanted and causing harm; but not when native species, like the endangered Clapper, have decided the new plants are just fine, thank you very much.

And the Clapper/Cordgrass situation in California isn’t the only example: It’s been recently reported that in parts of Arizona and New Mexico the Tamarisk/salt cedar plant (genus tamarisk) – for decades considered a blight that’s soaking up water, crowding out native plants, damaging the soil, and is basically an eyesore – has been ‘adopted’ by the Southwestern Willow fly-catcher (Empidonax traillii extimus), a listed endangered species, which seems to be selecting non-native tamarisk rather than native Cottonwood trees that the birds have lived in for generations.

So where does this leave scientists, conservationists, and most importantly, the environment itself? At this time, no one’s certain. As University of California, Davis environmental science professor Alan Hastings, stated: “Just thinking from a single-species standpoint doesn’t work.” While it’s important to consider all species in an environment – native and non-native alike – maybe one species shouldn’t be favored over another, but the big picture – the environment as a whole – is the more important value. Could non-natives outpacing natives be the progress of evolution – but accelerated by man? Maybe in time everything must change; the camel was originally a native of North America, but disappeared from the area thousands of years ago; tumbleweeds (Salsola tragus) are actually Russian Thistle, an invasive species, but have become a symbol of the American west. Maybe the Clapper and Fly-catcher are on to something:  It’s not what your home is made of; but what makes your home. And that’s something to clap about.


Michonne Says: I don’t understand how any plants can be un-wanted, even if they are those invay-sleeve kinds. If marmots see any plants that look like they don’t belong, we just bite them off and that’s that. And sometimes they taste good, but usually they don’t so maybe that’s why no one wants them around.

Posted September 21, 2014 by ECOVIA eco-adventure® in SciSun

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