The high quality Somme Prairie is increasing from two acres to seventy acres. Hundreds of vulnerable species that have been hovering on the edge of oblivion because of fragmentation, now may have a sustainable future.
If you had stood on the highpoint of Somme Prairie two hundred years ago (or 2,000 years ago), you would have seen rich treeless grassland rolling majestically to the horizon – to the south, the west, and the north. To the east, you would have seen a mile of prairie backed up by savanna and woodland on the moraine. Today from that same spot, off to the south, west, and north, you see businesses, parks, roads, and homes for people. Many of those people are glad a prairie survives and can recover.
Forty years ago at Somme, two acres of very high quality prairie remained, in scattered patches. Most plant and animal species are not sustainable in a two acre habitat. The prairie species, you can imagine, were shivering in fear. When we first started to rescue biodiversity here, the surrounding brush was gobbling up more prairie every year. In the absence of fire, brush kills every grass, flower, bird, butterfly, nematode, and fungus of the prairie. For forty years, volunteers cut back shrubs and trees. Brush tried to grow back as fast as we could cut it. We concentrated on the biggest and best quality openings. We lost some. Brush obliterated some, but most of those remnant patches recovered more and more, year by year. Yet, we didn’t have as many troops (or as much fire and seed) as we needed to make faster progress.
By 2010, Steward Laurel Ross and the volunteers of the North Branch Restoration Project had about thirty acres of prairie under restoration. But forty acres were still under shade. Volunteers are mighty, but we are spread over many sites. Thousands of generous friends and neighbors have contributed here, from a few hours to hundreds of hours each, but we have only been able to do so much.
Increasingly in recent years, Forest Preserve staff and contractors have focused resources on Somme. In 2014, President Preckwinkle and the Forest Preserves board approved its “Next Century Plan.” By 2020, according to the resulting project plan, there will be no brush in Somme Prairie. This is huge.
This work is a model of collaboration. Forest Preserve staff, volunteers, partners, and scientists work together. (See Endnote 2.) The following is a summary of the discussions the bird conservation planning group had that day. Bird conservation was just one part of the overall plan. (See Endnotes 3 and 4.)
1. The most important overall conservation goal for the 70-acre Somme Prairie is the restoration of its original prairie community – as large and fully diverse as possible. The birds are just one part of that community, but our main goal today is to focus on the birds part.
2. The basic bird-conservation objective is a large and unbroken grassland of good structure for breeding prairie birds, especially Henslow’s sparrow, dickcissel, sedge wren, savanna sparrow and possibly meadowlark.
3. Currently no prairie birds nest in Somme Prairie. But with increasing size and quality of habitat, breeding birds can be expected, in time. Currently, some prairie species breed at Air-Station Prairie (a few miles to the south) and Willow-Sanders preserve (a few miles to the southwest).
4. Grassland areas the size of Somme may have significant contributions to make. There are potentially about 100 acres of quality prairie habitat here, if we remove the brush barrier that separates Somme Prairie from formerly contiguous habitat in Somme Prairie Grove to the east. Recent studies suggest that the value of smaller urban grasslands can be higher than previously thought. The proposed work at Somme could combine with, inform, and inspire similar work at scores of existing and potential grassland bird breeding sites in the Chicago Wilderness region.
5. Would we be wise also to save shrublands here? No. For a site of this size, a single focus on grassland bird habitat is far superior to a compromise that would attempt to restore both grassland and shrubland. Other sites (including the adjacent Somme Prairie Grove) are successful and superior for shrubland bird conservation. More importantly, shrubs are a main threat to grassland birds – and challenging to manage. The agreed-on best strategy here is for the entire site to be restored as prairie.
6. After trees and brush have been cleared, there’s still a lot of work to do to eliminate such malignant and habitat-destroying invasives as crown vetch, reed-canary grass, purple loosestrife, and teasel.
7. But the major first-step threat here is shrubs and trees. When just a foot or two tall, shrubs are not in themselves a detriment to the grassland birds. But, in two or three years, between burns, woody plants with well-developed root systems tend to grow sufficiently to shade out the species of grasses and other conservative plant diversity that make for successful grassland bird nesting habitat. The plan is to treat shrubs, trees, invasive weeds, and seed planting in a step-by-step process. (See Endnote 3.)
8. Another principal threat is aggressive forbs such as tall goldenrod (Solidago altissima) and saw-tooth sunflower (Helianthus grosseseratus). These and other rank species can create a vegetation structure that blocks or retards the desirable establishment of natural prairie. Such “thug” vegetation is also not nesting habitat for most grassland birds. These areas frequently do not burn under the moderately flammable conditions of most controlled burns, as the fuel quality is low. The rank species are thought to obstruct better quality vegetation by shading it out and possibly by emitting chemicals from their roots that inhibit the growth of other species. One solution to this problem that has been effective in some cases is to seed diverse prairie vegetation and then mow the rank growth when it becomes too dense for the survival of desirable seedlings.
The new Forest Preserve plan (above) shows Somme Prairie outlined in red, Somme Prairie Grove in orange, Somme Woods in yellow and green, and Chipilly Woods in blue. |
9. We next visited the 85-acre Somme Prairie Grove (adjacent to the east) and considered relationships between it and Somme Prairie. A coordinated plan for the two preserves now makes more sense. The prairie portions of these two preserves are divided from each other by the North Branch of the Chicago River (which flows unnaturally in a deep, straight ditch) as well as by the Metra railroad tracks. Neither the ditch nor the tracks would impede prairie birds from using both sides as one larger grassland. (More on the opportunities here will come in a later post.)
10. A special feature of Somme is a continuum from quality prairie to quality savanna and shrubland to quality woodland (as we go east from Somme Prairie to Somme Prairie Grove and the adjacent 450 acres of Somme and Chipilly Woods. The restoration of such a rare continuum would benefit birds, plants, invertebrates, herptiles, and the ecosystem generally. (See Endnote 4.)
11. Relative conservation priority of shrubland, savanna, and prairie birds: They’re all important, but the prairie species are a higher priority, especially for Somme Prairie. Birds of shrubland and savanna are second priority.
12. We were entertained during our walk in Somme Prairie by a merlin (an uncommon mid-size falcon) which was being mobbed by blue jays in between bouts of the feisty merlin harassing a kestrel (a smaller falcon) and a sharp-shinned hawk. Perhaps this performance was a good omen for our bird conservation planning efforts here.
Then, one last thought:
Will Somme Prairie someday truly revel in 70 acres of very high quality prairie? No one knows. No one has ever seen very high quality prairie restored. But even “good” prairie would be a blessed improvement over the formerly advancing brush – and many plant and animal species are already thriving in some of the restored areas. How fast and how much the ecosystem can recover will be a fascination and inspiration to experience over the years ahead.
Endnotes
Endnote 1
The planning session on bird conservation was assembled by Becky Collings and Laurel Ross. The full roster for that field meeting included:
Forest Preserve staff: Becky Collings and Debbie Antlitz
Bird conservation and ecology: Jim Herkert (Illinois Audubon), Doug Stotz
and Dave Willard (Field Museum)
Stewards: Laurel Ross, Lisa Culp Musgrave, and Stephen Packard
Steward Laurel Ross has also long been a conservation leader as staff of The Nature Conservancy and the Field Museum. She is also on the Conservation and Policy Council that helps guide the implementing of the Next Century Plan. Thus, many contributions make a difference.
Endnote 2
In case "model of collaboration" sounds Pollyanna to anyone, let me hasten to assure you that "collaboration" does not mean an absence of problems. It means we all pitch in, respect each other, and work problems out, as best we can.
Endnote 3
Step by step.
The transformation of Somme Prairie became visible from Dundee Road on December 13th, 2018 with step one. A large "mower" chopped up the understory brush, as shown below:
Endnote 4
Does this post make too much of a fuss over birds, compared to the rest of the ecosystem? Yes, but. Birds often rightly get extra attention because the data for them is especially clear and strong. We know better how big preserves need to be (and what vegetation structure needs to be) for bird conservation than we do for most other species. Part of the reason for that, is that people have done more research on birds, in part because they have more constituency and support. Birds bring more supporters to conservation efforts than do rare walking sticks or snakes.
As conservationists, we care equally for now-rare ants, weasels, slime molds, etc. - but we have less complete data on their conservation needs. But there's data for many species in many habitat types that confirm the value of larger habitats. Thus, restoring size and quality for birds will likely help many other plants and animals for which we have less detailed knowledge.
Midwest invertebrate expert Dr. Ron Panzer, who studied Somme years ago, published data that strongly supported the value of large habitats and higher quality vegetation for invertebrate conservation. But he cautioned against relying on size and vegetation alone. Burn regimes and other features may be equally or more important. Conservation will be on increasingly solid footing as we learn more about the needs of more and more species.
Credits
John McCarter, Wendy Paulson, Arthur Velasquez, and Eric Whitaker: co-chairs of the Next Century Conservation Plan Commission – along with the scores of people who contributed to the planning process. And forest preserve President Toni Preckwinkle who coordinated the adoption of the plan.
Dozens of Forest Preserve staff and contractors as supervised by John McCabe who has much upgraded the professionalism of the Forest Preserve’s Resource Management Division.
Volunteers by the hundreds, including Somme Prairie co-steward Lisa Musgrave and Eileen Sutter who, with many leaders and volunteers, has headed up the seed-gathering crews of the North Branch Restoration Project.
Jeanne Muellner who took the great photos of the Henslow’s sparrow and the dickcissel at the Orland Grassland, where they both thrive in restored habitat.
Thanks for proofing and edits of this post to Becky Collings, Troy Showerman, Lisa Musgrave, Eriko Kojima, and Kathy Garness.
References
For an introduction to Somme Prairie Nature Preserve, check out captions and photos of Somme Prairie from a walk in late May - and a set of very different photos and comments from July.
Summary of the Somme Prairie plan
Chicago Region “Bird Conservation Network” birds of concern
The birds of conservation concern of the Somme preserves:
Woodland birds regularly breeding in Somme Woods include red-headed woodpecker, American woodcock, and northern flicker.
Shrubland and savanna birds regularly breeding in Somme Prairie Grove include brown thrasher, willow flycatcher, field sparrow, American woodcock, northern flicker, and eastern kingbird.
Prairie birds currently breeding in Somme Prairie include none at all, for decades. The pitiful fragments of surviving prairie are too small. Thanks to all who are helping the recovery of the plants and animals of Somme Prairie.
Exciting news Stephen! Grassland birds returning to the heart of the Chicago metro region would be an incredible accomplishment.
ReplyDeleteI wonder how long the battle will be with the brush re-sprouts before the roots finally give up the ghost?
Best of luck to all involved with this project.
David
My experience with a lot of brush is that those roots "never" (or at least for many decades) give up the ghost. If the fires stop, the brush comes back with a vengeance. To kill them, we have to paint the stumps or foliar spray the re-sprouts with herbicide.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteI recall Virginia rail north of Dundee in the 1950s. The site was probably much wetter (marshy) before the west fork of the North Branch was ditched north of Dundee. The WFNB flowed in its natural course in the 1950s south of Dundee until it crossed under the RR embankment. It no longer does. The WFNB was a favorite spot to play for me as a youth (despite being a major breeding ground for the Sea Lamprey- I did not know what those wigglers in the creek were until many years later.)
ReplyDeleteBirds do get many viewers, but I have not seen an example where the management ideas of birders were responded to by birds, ie the Black Crowned Night Herons or Yellow Headed blackbirds in the current manifestations of Lake Calumet. Much better to manage the plant community (which does help the insects and other smaller forms of life) than to do things for birds which have wings and the ability to make many choices.
Thanks JWPboss for good comments. You may be happy to know that the Virgina rail (and the sora) sometimes nest successfully in Somme Prairie Grove. (We've seen the chicks and come across nests when doing stewardship work.)
DeleteAs for the grassland birds, they've responded dramatically to our restoration work at Spring Creek, Orland, Bartel, and other sites.
And yet, as you suggest, the main effort is on restoring the prairie grasses and wildflowers - on which all the prairie animals depend.