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Re: Native, non-native and nearly native



Hey all,

Before I get into tonight's main event, an observation from the feeder: a
Downy Woodpecker and House Finch were sharing the suet this morning. The
woodpecker kept pecking at the finch's beak, almost as if it were a recent
fledgling trying to convince the bright red, obviously adult finch to feed
it. I eventually checked with binocs and saw that the finch had severe eye
lesions. I guess the woodpecker was trying to scare the finch off, and the
finch, with its eyesight mostly gone, could neither clearly see the
woodpecker's aggressive moves nor mount an effective defense/attack. Or
something...

Of *course* I have to weigh in on the native plants thing... With the
advice that, you can't make this decision based on some arbitrary rule
about how many miles separate your yard from the plants' native range. You
have to learn about each particular plant species, and decide on its own
merits.

For examples from the bird world: the Rock Dove comes from a whole
different continent, yet in the US does little if any ecological damage,
inhabiting a niche which probably no native bird could fill, and even
providing abundant prey for urban-nesting Peregrine Falcon families. The
Canada Goose is endemic to this continent, and yet has spawned these non-
migratory populations that wreak all kinds of havoc on aquatic ecosystems.
Monk Parakeets from Argentina are a potential agricultural threat, but
from the point of view of native birds, they are far safer to have around
than Brown-headed Cowbirds from just a few states to the west. And
somebody already brought up House Finches from the southwestern US, which
are doing much better in NC's native habitats than the Chinese imported
Ring-necked Pheasants. One recent fracas has broken out over the Trumpeter
Swan; attempts to restore the nearly extirpated US wild population has in
some areas instead produced a non-migratory habitat-disrupting menace
nearly as bad as the terrible Mute Swan, and further battles have arisen
over whether or not there was ever a population of the species in the
eastern US which ought to be restored...

The same goes for plants. I've heard that some natives can take over a
yard if not watched carefully, like Chickasaw Plum or Devil's
Walking-Stick (Aralia spinosa), to say nothing of raspberries and
Pokeweed.. I've also heard that the ever-popular Southern Magnolia has
become quite a pest on the northern Outer Banks, where it's crowding out
the native oak-based forest community; the on-campus woodlots at Duke also
have a disturbing density of magnolia saplings in the understory.
Meanwhile, Camellias (which are Chinese) get planted everywhere, but I
have yet to see or hear about them spreading or causing problems (though I
still like them less than the "Lost Camellia", Franklinia altamaha, now
extinct in the wild but available from some nurseries). Lantanas are a
noxious weed in Florida, but there are native species in Texas, and up
here in the Piedmont they seem more prone to die than spread.

And Nathan brings up Common Reed, Phragmites, which is an especially wierd
and complex case. Rather than describing it here, I'll direct people to
the exotic species page of my website
http://www.duke.edu/~jsr6/Exotics.html
which has about half a dozen links on that one species alone (though the
first one about the ground sloth dung is broken, sorry!)

The ultimate point being that "native" and "non-native" is an artificial
dichotomy we've forced upon nature. There are different degrees of
nativeness, and more importantly different degrees of invasiveness (oops,
I see that Will just posted the same point while I was typing). Some
species play well with others, and some don't. The challenge for us in
landscaping our yards for wildlife, is that so many plants which bear
bird-attracting fruit and nectar tend to form monocultures which then
exclude the other plants that provide insects which birds need to raise
their young. Hence the reason that Japanese Honeysuckle, English Ivy,
privet/Ligustrum, Autumn/Russian/Spiny-Olives/Elaeagnus, Chinese and
Japanese Wisteria, Nandina/Heavenly Bamboo, and Chinese Tallow Trees are
ultimately bad for the birds, even though we might see Cedar Waxwings,
hummingbirds, or other species visiting them.

While Nathan had the best advice - if it was not growing here when
Columbus arrived, don't plant it - even I can't hold myself to that high a
standard; we have two Buddleias out front, some Pineapple Sage, and had a
Lantana but it died over the winter. But I think a good minimum standard
is the North Carolina Botanical Garden's list of "Invasive exotic plants
to avoid in the southeastern United States" at
http://www.ncbg.unc.edu/plants-to-avoid-SEUS.htm
If you never plant anything off this list, you're doing better than 90% of
the folks out there (including my mother-in-law and one or two of my more
ornery neighbors). If something from the list is growing in your yard,
don't despair, we all have them too; my yard has 18 species from this
list! It's just another home improvement project, right up there with
insulating the attic, building a deck, and caulking over the settlement
cracks. If you actually remove everything on this list from your yard, you
deserve a medal!

Shopping for plants exclusively at places like Niche Gardens, the NC
Botanical Garden plant sale, Gardens of the Blue Ridge, and similar
outlets which specialize in natives and avoid invasives is also a good way
to go. Sharon Funderburk's nursery, which is having an open house this
weekend, is another good choice (especially if we can convince her to drop
the Iris pseudacorus). I've compiled a list of good sources of native
plants on the Duke Natural History Society website
http://www.biology.duke.edu/dnhs/
under "Online Resources" (don't worry Sharon, I'll get you up there soon!)

And I'd like to close with something even less bird-related, a poem which
Joy Greenwolfe (who's on this listserv somewhere) posted to the Ellerbe
Creek listserv, which gives exotic invasive plants an artistic twist:
http://www.supernet.net/%7Ejclark/fiction/wisteria.html

Good birding, and happy horticulture,

Josh


Joshua S. Rose
Duke University
Department of Biology (Zoology, R.I.P.)

jsr6@duke.edu
http://www.duke.edu/~jsr6/