[APWG] Ecosystem Restoration and Species and Micorhabitat Matching Re: What about native grass and herbaceous perennial colonizers?

[Wayne Tyson]

APWG:

While I am not familiar with Maryland's indigenous species, what I think I 
understand is there are some well-known indigenous "pioneers" that "invade" 
or colonize open niches rather readily, some by wind (to some extent) and 
others by animals. Others may "march" outward from established colonies 
opportunistically if no other vector mechanism is present. Birds are common 
dispersal agents, and humans can mimic their activities to accelerate 
succession and even the development of climax associations. I'm certain that 
I'm not telling you anything you don't know, but since this is a group 
email, I thought some mention of the obvious might be useful to the 
discussion.

There are a few ways of inhibiting new colonists (providing they don't have 
some clever means of evading them), such as filling the "vacated" niches 
with species best adapted to the conditions present on that specific 
location (there is a lot more structural and functional heterogeneity in 
forest habitats than is commonly recognized). Conversely, microhabitats that 
do not exhibit conditions congenial to some species mitigate against such 
introductions (this is one of the causes of "failure" in ecosystem 
restoration projects). I tend to agree in principle with Dremann's comments 
about immediate niche-filling as a means of reducing colonization success of 
some species.

Out here in the West where I am more familiar with habitat conditions, one 
of the most useful species assemblages for this purpose (but almost entirely 
ignored, even though quite common and widespread, but also widely degraded) 
where the appropriate microhabitat conditions are present are the 
cryptobiotic soil "crust" associations. I suspect that mosses, for example, 
are quite common in Maryland. Other plant species and species-specific 
predators combined with other techniques can at least reduce the necessity 
for hand-weeding, if not eliminate it. I am, however, not a great fan of 
hand-weeding or any other form of weed-niche creation. Killing invaders in 
place helps minimize niche-creating disturbance.

I am a bit surprised to learn from Dremann that Maryland and California have 
so many species in common. In Southern California, for example, Sisyrichium 
bellum can be a reasonably successful self-seeder under the right 
conditions, but Dremann is no doubt right that "plugs" would be better. 
Leymus triticoides is a very "useful" plant for suppressing weeds, but it 
can be quite a "weed" itself. I am unaware of any "herbicidal" qualities of 
this species, but would like to learn the specifics. It does, however, form 
a very tight sod and has lots of leaves and stems. Shading and other 
microhabitat-shifting may be largely responsible for its apparent 
"allelopathic" action.

Again, I agree that 100% elimination of all species alien to that site 
(including "natives" from other habitats) is a laudable goal in helping 
preserve and enhance a small fragment of a once widespread "Eden" in that 
region, even though I will probably never get to see it.

WT

----- Original Message ----- 
From: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
To: <ialm at erols.com>; <apwg at lists.plantconservation.org>
Cc: <rwg at lists.plantconservation.org>
Sent: Thursday, August 18, 2011 8:13 AM
Subject: [APWG] What about native grass and herbaceous perennial colonizers?


> Dear Marc and All,
>
> You mention that when you are doing your weeding in Maryland and want
> indigenous early succession species, you are mentioning non-grass species?
>
> What about the native perennial forest grasses and herbaceous perennials
> that we saw at the Great Falls National Park in Maryland when I was out
> teaching classes to DELDOT in 2000, or the other native grasses like the
> Little Bluestem that I saw growing along the BWI Parkway in places?
>
> The Elymus or Wild Ryes that have been so successful here in the West, and
> in the forests of the East, a pinch of local seeds of the Canadian and
> Virginia wild ryes should be sown in every spot where you pull a weed.
> These wild ryes are strongly allelopathic, giving off natural herbicides
> that will suppress the resprouting of weeds seeds that may still be in the
> soil wherever you have already weeded.
>
> Sowing in wild ryes immediately after weeding an area, is like putting in
> permanent weed seed suppression workers, plus they help start the natural
> succession. The switchgrass, little bluestem, indiangrass and gama grasses
> would do the same thing, but the seed for the wild rye would be the
> cheapest and easiest to start with, then you could graduate to the more
> expensive grasses once you get the wild ryes figured out.
>
> Also, everyone should look at the herbaceous perennials, like DELDOT did
> over a decade ago, that you can read at
> http://www.ecoseeds.com/deldot.html when I did a class for them on
> roadside native plants.  It might be interesting to go back and view the
> DELDOT plantings, and see what worked after a decade?
>
> The weeders of the East coast, should be looking at replanting all of the
> non-tree and non-shrub forest understory plants that should be there in
> your Eastern forests, like the sunflower family which will produce the
> cheapest seeds like the goldenrods and rudbeckias, which at the same time
> are very excellent weed killers.
>
> Also try the legume family, the Claytonia which is a very strong
> allelopathic plant and a good weed killer,  and try all of the
> Eupatoriums, the milkweed, and the mint family.
>
> And do not forget two other strong weed killer of Maryland, the Blue Eyed
> grass or Sisyrinchium and the native violets that will have to be planted
> as plugs.  And the frosting on the cake would be to replant a few Silenes
> or some Shooting stars around your restoration sites, in the proper places
> for them.
>
> Once you surround your weeding efforts with 99% cover of these local
> native grasses and native herbaceous plants, they can permanently suppress
> the weed seeds from ever germinating, and that is very useful to protect
> the spots where you have weeded already.
>
> I hope this information is useful for the East Coast weeders reading this
> list, and this method would work for anywhere in the world where you are
> weeding out exotic plants, and want to end up with a weed-free local
> ecosystem as the end product.
>
> We need to go from weeding, to restoring 99% cover native grass and
> herbaceous perennial understories that can help keep the weeds from ever
> coming back.
>
> Sincerely,  Craig Dremann (650) 325-7333
>
>
>
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