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Friday, July 18, 2014

Brainstorming the Ecosystem: July 13, 2014


 Tom Vanderpoel offers suggestions

Stewards often visit each others’ sites to share ideas. It is a special treat when the highly experienced Tom Vanderpoel schedules a visit to Somme Prairie Grove. As Land Manager for Citizens for Conservation, he has done decades of detailed work on a few high-quality restoration areas. A person just doesn’t get the knowledge Tom has without long and intense focus.  

Question 1.
We visited the “Pothole Pond” where a stand of solid cattails had increasingly crowded out nearly every other plant over about an acre. (Which cattails? Both species – for scientific names of all species, see note at end.) After pulling and scything the edges for years, with modest results, we herbicided the patch and planted diverse wetland seed about a decade ago.   

The pond is now diverse and beautiful, with five endangered or threatened species and, more important, a great deal of conservative diversity. BUT a couple of patches of bluejoint grass have started to spread as monocultures. We excluded bluejoint from the early seed mixes because of this very worry. Will it now wipe out this diverse (but immature) community?

Tom Vanderpoel, right, has supervised some of the region's most diverse wetland restorations. Here he trades thoughts
with Rob Sulsky, who has been developing propagation techniques that help his efforts. 
Tom has two conflicting thoughts. On the one hand, he thinks that the monocultural aspect is likely temporary and brief. The other species will re-invade the bluejoint sod as that matures.

On the other hand, he says, “If you see this continue, you might try damaging the bluejoint with Poast (an herbicide that kills only grass) and inter-seeding with tough sedges and diverse forbs right after.” Might. He doesn’t know. Every site is different, at this stage of our knowledge. Watch carefully. Try different approaches.

Question 2.
The sedge meadow north of the Swale Pond has almost the opposite problem. For decades it’s been a “few-culture” of mostly bluejoint grass and sedge (pellita). Years ago he said of this area, “I like it. Now start putting the forbs in.” I didn’t. There’s only so much time, and I understood needs better on the upland prairie/savanna/woodland areas. But this beautiful wetland deserves better.
The Swale Pond itself is richly diverse, but the formerly grazed area around it is almost a monoculture
(or "two-culture") of blue joint grass and sedge. 
“What species, specifically?” I now ask. He recommends: boneset, water dock (“that one the butterflies appreciate so much”), spotted Joe-Pye-weed, swamp candles, shining aster (puniceus), tufted loosestrife.

Tom says, “I think a few of those species will break down the monoculture and promote diversity. Then soon it will be orchids and everything else.” Here and there, already, were patches of winged loosestrife. Tom recommended seeding especially around those areas.

Question 3.
We looked at a “new” (most work done in the last ten years) wetland in the northwest corner. It had been dense ash, sandbar willow, reed canary grass, etc. Now, with modest seeding, it is mostly rice cutgrass, manna grass, and other such common but classy species – with the occasional eared gerardia and even prairie white-fringed orchid. Patches of iris and cordgrass are here and there – along with continuing infestations of reed canary, purple loosestrife, cattail, and common reed.   
 
An early-stage wetland is vulnerable to monoculture-forming invasives and "thugs."
Tom said, “Pretty cool start. Be relentless on the reed canary; it’s the worst invasive we have. Put the big sedges into the cutgrass; pour forbs into the sparse areas; bur reed could be important here.” He looked darkly at a couple of areas where the herbiciding of reed canary or loosestrife had left a few square feet of bare ground. “These are dangerous for re-infestation by junk, he said.” Manna grass happened to be ripe in the area; Tom started grabbing handfuls of it and broadcasting them on the bare patches.




Left: a bag of seeds of the sedge Carex vesicaria (a species that may deserve to be on Tom Vanderpoel's sometimes-changing list of "The Ten Warriors" - species that help seal off wetlands from invasion by malignant species)












He glanced at the ditch of cattail and river bulrush along the railroad track to the west. “You might want to nuke that whole stand,” he said. Lot’s more to discuss here, but I wanted to save time for one last place.

Question 4.
One white oak area needed thought. Though Somme Prairie Grove was savanna originally, one hundred years of farming had eliminated the bur oaks from the north half. When these 90 acres were bought for forest preserve, white oaks were planted in the former pastures and crop fields. Whites are okay savanna stand-ins for bur in the short run, but it seems like fires of savanna intensity are gradually burning them out. Young burs (planted by us and squirrels) are ruthlessly browsed to dwarfs by the deer. We’re protecting them with cages, so they can replace the whites over time, if the whites continue to succumb to fire.  

After thirty years of restoration, some of the open white oak areas support rich, diverse, conservative savanna herb flora: grove sandwort, violet bush clover, two-flowered Cynthia, small sundrops, wild hyacinth, savanna blazing star, pale Indian-plantain, Canada milk vetch, slender wheatgrass, wide-leaved and Leiberg’s panic grasses, and scores more.   

Downwind of the open-est part of the grassland, the big white oaks are dying from fire. Underneath, a few-culture of big bluestem etc. is replacing the much better stuff. How concerned should I be?

Intense fire is critical to the natural dynamic of the savanna. For one thing, it controls invaders. But at Somme it's been
killing (artificial, planted) white oaks that may be temporarily important to the structure of the habitat. 
Tom recommended back-burning through the best groves. “You wouldn’t want to lose diversity of this quality,” he said.  Yet, lack of sufficient fire is often a big challenge. Putting more restrictions might add too much complexity to burns, conducted by contractors who don’t know the site intimately, and who are at the mercy of weather, traffic on nearby highways, competition for time and resources from other deserving sites. I wonder if there are better solutions. Perhaps more burn resources, some day? Perhaps creative fire breaks. Perhaps speeding up the recovery of the bur oaks by spending more time shelping them?   

This question seems not resolvable at this point. Comments from readers are (always) welcome.


Index of scientific names for common names cited.

Scientific names of plants cited, from Plants of the Chicago Region by Swink and Wilhelm (1994)

ash – Fraxinus pennsylvainca
big bluestem – Andropogon gerardii
bluejoint grass – Calamagrostis canadensis
boneset – Eupatorium perfoliatum
bur oak – Quercus macrocarpa
bur reed – Sparganium sp.
Canada milk vetch – Astragalus canadensis
cattail – Typha latifolia and angustifolia
common reed – Phragmites australis 
cordgrass – Spartina pectinata
eared gerardia – Tomanthera auriculata
grove sandwort – Arenaria lateriflora
iris – Iris virginicus
Leiberg’s panic grass – Panicum Leibergii
manna grass – Glyceria striata
pale Indian-plantain – Cacalia atriplicifolia
purple loosestrife – Lythrum salicaria
reed canary grass – Phalaris arundinacea
rice cutgrass – Leerzia orzoides
river bulrush – Scirpus fluviatilis
sandbar willow – Salix interior
savanna blazing star – Liatris scariosa
sedges, tough or big (“The Ten Warriors” that compete especially well with reed canary): Carex stricta, haydenii, buxbaumii, pellita, lacustris, trichocarpa, atheroedes, utriculata, sartwellii, emoryi, and aquatilus
shining aster - Aster puniceus
slender wheatgrass – Agropyron (or Elymus) trachycaulum
spotted Joe-Pye-weed – Eupatorium maculatum
small sundrops – Oenothera perennis
swamp candles – Lysimachia terrestris
tufted loosestrife  – Lysimachia thrysiflora
two-flowered Cynthia – Krigia biflora
violet bush clover – Lespediza violacea
water dock – Rumex orbiculatus
white-fringed orchid – Habenaria (or Platanthera) leucophaea
white oak – Quercus alba
wide-leaved panic grass – Panicum latifolium
wild hyacinth – Camassia scilloides
winged loosestrife – Lythrum alatum


6 comments:

  1. Great post! Fun to listen in to the discussion... In terms of the fire intensity issue with your white oaks, I imagine you've already considered the possibility of mowing the grass down nearest the oaks prior to ignition? And/or using spot ignitions (lighting many spot fires instead of long lines) through the areas of vulnerability. It's quite a conundrum - thanks for sharing it with us. It's nice to learn from others, but also nice (oddly) to hear others talk about their own challenges-without-clear-answers.

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    1. Yes, spot ignitions could go a long way, if the planners and contractors are up for it. Perhaps it's the next thing to try?

      Mowing hasn't worked well for us. The thirty foot flames we often get here just bend over the mowed area and do their scorching. More extensive mowing and raking are a possibility, but it would be nice to find a more organic and elegant solution.

      Thanks for the good thoughts and perspective.

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  2. It has been a while. I am glad to see this recent blog post.

    The one central theme I have consistently heard from land managers is a problem with a dominating grass. I have heard this from those managing Bennett Bog in New Jersey. I have heard this from the manager of the Whitney Preserve in South Dakota. I have certainly heard this from many people in between these areas.
    If I have learned one thing from trying to grow native plants in my garden, it is they always do better without competition, resource limitations, and predators. This is great if your goal is to produce seed for restoration. However, this becomes a big problem in an actual restoration setting when one species dominates.

    We seem to latch on to temporary solutions because we can observe immediate results. Examples include, taking the scythe out and cutting it or attacking it with herbicide. These measures are necessary in a number of cases, but I would like to see stewards try to use natural processes to restore our local ecosystems when possible.

    If Andropogon gerardii is the problem then I suggest finding a native prairie with individuals of this species that have a level of robustness in character for a remnant. Dig up a small amount of soil and roots and transfer this to a restoration area being dominated by this species. Measure the robustness of the individuals surrounding the introduction area over time to determine if the vigor of the plants in the introduction area have been brought down to the level expected. If success can be measured then repeat and tell others about your success.

    This being said, I think many of our native plants tend to grow in patches that are near monocultures. Sometimes these monocultures are big patches and sometimes they are smaller patches. Whether or not this growth pattern appears to be a problem can depend on scale and habitat heterogeneity. Knowledge of how a species behaves in a remnant should be the bench mark that determines whether a species is behaving appropriately in a restoration setting or whether there is a problem.

    Regarding the White Oak Area, I have observed many of the species you list growing in 100% sun. Just because people have cut down all the oaks does not mean the ecosystems knows it is no longer a savanna. I think a majority of these species could survive until a canopy of burr oaks can get established. However, I also believe Andropogon gerardii will dominate if nothing is done.

    Regards,
    James

    http://www.njaudubon.org/SectionConservation/NJAUnstaffedWildlifeSanctuaries/BennettBogs.aspx

    http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/southdakota/placesweprotect/whitney-preserve.xml

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    1. James, thanks for the good comments. At Somme, we've had a gratifying response to big bluestem dominance treated by inter-seeding. All we did was broadcast seed into a solid bluestem patch. Now the bluestem is much reduced, apparently from competition from abundant prairie clovers (purple and white), shooting star, betony, cream gentian, and many many others. Tom Vanderpoel suspects that nearly all spring-blooming species can be successfully seeded into bluestem - given regular burning.

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    2. Although I too have seen the species you mention establish in restorations, good results are often restricted to small portions of a site for reasons that I cannot explained. When conservative species are established, most often they are fewer and more widely spaced than would be expected to occur in remnants. I cannot say whether the populations of these species will increase over time or maintain only a low number of individuals. The question that comes to mind is “In your experience, looking at many different restorations, are the results you have achieved at Somme the rule or more of an exception?”

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    3. It's my experience that conservative seed establishes with great diversity and density if plenty of seed is broadcast, followed by regular burning. I should say that I have extensive experience with inter-seeding old pastures and similar poor quality remnants. Less experience with plowed ground restorations. Somme Prairie Grove in many parts is as dense as an original prairie with many conservative species. The limiting factor has been sufficient conservative seed (and my time, which is widely spread on other sites). At Grigsby Prairie (southwest Lake County) and Flint Creek Savanna (southeast McHenry County), Tom Vanderpoel's work has shown similar results in less time on former plowed ground - with a lot more intensive work.

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