In Piedmont Pennsylvania, where I'm very much involved in serpentine grassland restoration at several sites, we are achieving good success and learning as we go by applying the adaptive management approach, which includes applying experimental design principles to routine management activities and monitoring carefully selected key indicators long-term. This is evidence-based management in which a management team is accountable for the results. You can see two adaptive management plans for serpentine grassland restoration on my website. Go to www.continentalconservation.us, click on Publications, scroll down to Other Recent Publications, and download the first and fourth items. Implementation is well underway at both of those sites. Incidentally, my ResearchGate profile photo was taken at a serpentine grassland in Riserva Naturale Monterufoli-Caselli, one of several protected areas of serpentine vegetation in Tuscany, where, in the 1580s, Andrea Cesalpino was the first natural historian in the West, and maybe anywhere, to note a connection between plant species distribution and bedrock type.

Thanks for your reply.  So can you please outline the successful steps you took over time, whose land was it in PA and why was it being managed (i.e. after construction?), how many species of grasses and wildflower have been planted/sown, and what is the finished native plant cover percentage, and how big is the area you were working on, and did you fertilize and with what fertilizers, and what was the total cost per acre?

1. whose land was it in PA ¶ Conservation agencies and land trusts have been buying up serpentine barrens in the Piedmont since the 1980s, when the land conservation community began to realize they would be lost to development otherwise. Unfortunately about half of the serpentine grassland sites documented by botanists a century or more ago have been lost to development. Growing recognition of the importance of endangered species recovery has spurred those agencies and land trusts to undertake restoration, as well as protection, of the sites. ¶ 2. why was it being managed (i.e. after construction?) ¶ The main reason why restoration is needed here is that most of the serpentine grasslands have lost upwards of 90% of their area to tree invasion in the 70-80 years since the beginning of fire exclusion. Despite the toxicity of the mineral fractions of soils weathered from serpentinite for many plants, in a year-round high precipitation environment like ours the lush tree growth can overwhelm the mineral soil with organic matter deposition, providing a buffer that allows colonization by trees and other plants that outcompete the grassland species. Chronic tree-killing disturbance is essential to the maintenance of any grassland in the East, although there is good reason to believe that serpentine soils slow plant invasion enough that the severity or frequency of disturbance required for grassland maintenance is lower than in other kinds of grasslands. There is an emerging consensus that Native American management of the landscape using fire was the principal tree-killing disturbance in the Piedmont over the past 3,000-9,000 years and perhaps longer; for the several million years before about 13,000 years ago, it was a suite of megaherbivores (2 mammoths, 1 mastodon, 2 giant ground sloths) and mesoherbivores (7 cervids, 3 peccaries, 2 horses, 2 tapirs, giant beaver). ¶ Our procedure begins with tree removal, ideally including stump harvesting. Often it is also necessary to reduce soil organic matter built up from the 10-20 tons per acre of leaves that forest trees shed each year. SOM reduction is accomplished by skimming the top few inches of organic soil from areas where trees had completely replaced grassland using a backhoe or front-end loader and hauling it off-site in a dump truck. I presume tree invasion and tree removal are not significant issues in most California serpentine grasslands. ¶ 3. how many species of grasses and wildflower have been planted/sown ¶ At most sites, restoration areas are adjacent to intact, mature grasslands and the seed bank of the roughly 150 characteristic native serpentine grassland vascular plant species is robust. Where restoration areas are not adjacent to a seed source, seeds are harvested from the nearest indigenous stands -- by hand for most forbs and sparsely occurring grasses and by machine for certain abundant grasses -- and dried, cleaned, and sown across the restoration area. Good results are obtained by propagating critical species, such as those that are threatened or endangered, as plugs in a greenhouse and then planting by hand using volunteers. Because serpentine grasslands include so many threatened and endangered species and because they have such high value for scientific research, nothing should be planted in them from a source other than another part of the same contiguous serpentinite outcrop or, after due deliberation among expert stakeholders, a nearby outcrop. ¶ 4. what is the finished native plant cover percentage ¶ Where the organic soil horizons are thin or nonexistent, within 2-3 years we get virtually 100% native characteristic serpentine grassland species with ground coverage varying from 50-100%, depending on soil thickness. The proportion of nonnative or non-grassland species coverage increases with the percentage of soil organic matter residue. The outcome on most sites with significant nonnative or non-grassland species coverage is improved at the first moderate summer drought, when most species not characteristic of the native serpentine grassland flora are "fried," and with prescribed fire. Most sites are maintained after restoration by prescribed fire, which keeps out most invaders with the exception of a few, fire-tolerant woody nonnatives that have to be treated with herbicide (black locust, autumn-olive, glossy buckthorn). ¶ 5. how big is the area you were working on ¶ So far at the sites where I’ve worked, restoration treatments have been applied in patches of up to 10-12 acres at a time. ¶ 6. did you fertilize and with what fertilizers ¶ Never, ever use fertilizer in serpentine vegetation restoration! If we could economically defertilize, we would. Defertilization in some ecosystems involves addition of elemental sulfur to temporarily lower pH or addition of sugar and cellulose to feed soil microbes that temporarily sequester N and P, but lowering pH would be of little or no value in a serpentine grassland and I know of no one who has tried the sugar+cellulose treatment on serpentinite-derived soils. Theoretically it might help to add soluble forms of magnesium and nickel (never calcium), but I know of no one who has tried that at a landscape level. ¶ 7. what was the total cost per acre ¶ Cost per acre varies widely among sites and situations, even within the confines of the eastern serpentine barrens territory. Sorry, it would be useless for me to generalize in a way that would be helpful in an entirely different climate with different ecosystem dynamics, as you have in California.

Thanks for your reply.  Addition of phosphorus to help the germination of native seedlings have been tried here in California with success, that you can read in the 1987 paper at  "Revegetation of Serpentine Substrates: Response to Phosphate Application" that is on Research Gate.    We are finding that even in serpentine soils, the seedlings of each native species need a minimum soil nutrient threshold profile for survival.  Otherwise the seedling can sprout and die without the minimums available. 

P.S. For the cost of seed harvesting and sowing, what the the cost per acre, and what was your total seed in pounds sowing rate per acre?

Roger Koide and Hal Mooney's findings reinforce my point about vast differences in climate and ecosystem dynamics making between-biome comparisons suspect. They found enhanced productivity with P addition, but productivity is exactly what we need to minimize here in the East, where hundreds of highly productive and highly competitive native and nonnative species are poised to invade serpentine grasslands at the slightest provocation. Our soils have been artificially enriched in N by many decades of atmospheric deposition from anthropogenic sources to the degree that some formerly N-limited systems have transitioned to P limitation. Although the experiment hasn't been done, it's fairly clear to me based on the vigorous responses of the characteristic native serpentine grassland species to even severe soil organic matter reduction, together with the density of invasives in restoration areas with substantial residues of SOM, that P fertilization here would be counterproductive. It seems likely that the key difference between Eastern and Western serpentine grasslands is moisture availability and its temporal variation. Eastern serpentine grasslands, contrary to many people's assumptions based on the xeric affinities in other habitats of many of the characteristic species, are not moisture-limited except during infrequent droughts. The species composition is an odd mixture of xeric, mesic and hydric species interspersed at a fine scale on the landscape. The soils, despite their anomalous mineral composition, are moist loams, and in most years we have roughly the same amount of precipitation every month. ¶ Unfortunately there is no way for me to calculate the cost of seed harvesting and sowing because it involves dissimilar combinations of volunteer effort and staff time among widely disparate organizations and agencies. Likewise I can make no generalizations about sowing rates because there is a wide range of variability from year to year and from site to site in availability of staff and volunteer labor at the critical harvest times, acres available for harvest, acres available for sowing, funding available for staff time, etc., etc., etc. I'm sorry I can't be more specific. Seed harvesting and sowing have invariably been opportunistic activities at several levels. We sow all that we harvest at each site during each year when harvesting can be achieved. The sowing rate is the amount of seed harvested divided by the area where the seed is sown. It has been impractical in virtually all cases I am aware of to try to match the harvest amount with a target sowing rate and a target sowing acreage. In any case, I'm convinced that establishment rates, which in an ideal world determine sowing rates, vary widely among species, among years due to weather, and even more widely between the Eastern Piedmont and the California serpentinite belt.

Can you make a guess at the cost per acre?  For our serpentine soils out here, when they have been bulldozed like for a pipeline, I am estimating the cost to restore at about $1 million per acre, if you are going to use locally harvested seed? 

If all of the restoration work is to be done by corporate contractors funded by the developer who is doing the damage, that's probably a reasonable estimate. In my neck of the woods, because this type of restoration work has so far always been done on a shoestring by cash-strapped nonprofits or underfunded and understaffed state and county agencies, corners are cut to fit tightly constrained budgets and some of the work has to be done on a volunteer basis or it never gets done. If a serpentine grassland here were to be destroyed by a Texas-based fossil fuel conglomerate building a gas pipeline (pipelines, drilling pads and wastewater containment ponds are going in other parts of Pennsylvania because of the shale gas fracking boom), I wouldn't hesitate to propose $1 million per acre at the start of negotiations. I'd bet your local Nature Conservancy chapter would be willing to provide some experienced stewardship staff members to sit down with you and other restoration ecologists to brainstorm a realistic itemized estimate for labor and equipment costs, based on the assumption of hiring contractors for the heavy lifting and doing the job thoroughly and based on best available science and expert judgment.

Just one further note -- I would never put a per-acre cost on this kind of work. It's certainly not true that restoring 2 acres is twice as expensive as restoring 1, or 100 twice as expensive as 50. Neither is it true that the cost of restoring 10 acres at one site is predictive of the cost of restoring 10 acres at a different site. The credibility of a cost estimate for restoration work hinges on tasks being itemized on a specific project basis.

We have a PG&E gas pipeline relocation project that went through about 10 acres of serpentine grasslands in the Town of Woodside in San Mateo County south of San Francisco, that was about 95% weed-free habitat, and now the company has planned to revegetate the area over the next five years.   Anyone else have a construction project trying to do ecological restoration of serpentine right now, and what are/were the costs per acre?

Started working on 15 acres of serpentine grasslands across the freeway from the PG&E serpentine acres, and without much work than mowing the weeds to stop them from producing more seeds, finding ancient dormant naive seeds coming up at 10-20 seedlings per square inch that I estimate are between 100-250 years old. On the 15 acres in April and May had 500 million wildflowers blooming--see https://www.ecoseeds.com/kite-hill.html -- Ending up one of the best wildflower spots in the area!

Even with only five inches of rainfall during this California drought, still getting rid of the exotics, the dormant native seeds keep sprouting up and taking the weed's places permanently.

Here is how one spot in the 14 acres of serpentine, located across from 144 Alta Mesa in Woodside, California, making the change in only one year's time...and unearth the dormant native seeds, in areas you would NEVER expect that those seeds are still in the soil.

The very easy method, is just NEVER allow the weeds to make ANY more viable seeds--by mowing the immature seeds as they form, at least once a month.

I will be out mowing the flowers off the remaining yellow star thistle (YST) plants tomorrow (early August)

And the paradox is that we have needed to leave some of those flowers during the summer for the rare Western bumblebees that have active hives on the site. Since the summer blooming wildflowers have not recovered yet, they need those weed YST flowers to survive through the summer.

The lession here is, never be so enthusiastic in eradicating ALL of the weeds at the same time, so you do not accidentally destroy the only food or nectar source for the native insects.

Another example in California, is the weed Filaree [Erodium] which for the last 150 years is the only food source for the California harvester ant--after we exterminated its original food source--the seeds of the native Stipa grass.

Seven years ago Roger Latham wrote--

6. did you fertilize and with what fertilizers ¶ Never, ever use fertilizer in serpentine vegetation restoration!

That might be true, if we never brought our exotic domesticated grazing animals from Europe and elsewhere, and these already poor soils got their nutrients removed, so that native serpentine genetic ecotype native seedlings can no longer survive.

You can find this out, by harvesting some native seeds from the serpentine site, and also put the top three inches of serpentine soil in a pot or box that has been heated to 140 deg. F. for an hour to sterilize. Then, sow those seeds and water every day, and see if they survive to maturity or not. Probably not, but that is what that experiment will tell you.

I have put together a PowerPoint, showing where this year we added 2,000 pounds of organic fertilizers to the serpentine area, where the native plants are showing where grazing in the past, stripped out the nutrients, below native seedling survival thresholds--at https://www.ecoseeds.com/woodside-kite-hill-story.pptx -- see slides 24, 25 and 26.

WARNING--If you are a person who strongly believes, to NEVER use fertilizers in serpentine restoration, please DO NOT view those three slides, because that 2,000 pounds of fertilizers will take your breath away, and I do not want to hear that anyone had a heart attack from viewing my work!

Another method you can do to find if your grassland needs fertilizing, is if Zombies exist and if the stand is all old plants, and has not reproduced in a long time. You can read my paper at https://www.ecoseeds.com/1-SEARCHING-FOR-ZOMBIES.pdf

WELCOME to KITE HILL Wildflower Preserve in the Town of Woodside, in San Mateo County to view fertilizing results. Wildflower and native grassland projects need close mowing and raking in next 30 days. This is an invitation to view "Fertilizing the Serpentine" for restoring wildflowers-- I am writing to invite your grassland and wildflower restoration ecologists to come this spring and view the results of my fertilizing of the serpentine at the Kite Hill Wildflower Preserve in Woodside this spring. This week I added bone meal, blood meal and mulch, to fix an eroded slope. I put down (per acre equivalent) 1,000 pounds of bone meal, 1,000 pounds of blood meal and 200 cubic yard of mulch on the serpentine soil. No seeds will be planted, just fertilizing to give any dormant seeds still on the site. I am anticipating very close to 100% natives, with a very low amount of exotics. I have been adding fertilizers and mulch to this serpentine grassland soil for three years now to get rid of the weeds, with very good results. When properly fertilized, the native seedlings sprout at the rate of 5-10 per square inch. Park behind Jane Drive gate--Google Maps address is 300 Jane Drive, Woodside, Cal. Walk through the pedestrian gate and walk down Jane Drive to the I-280 fence and turn to the left and walk along the fence line. Look for the Toyon bushes along the I-280 fence to see the results. For your wildflower and native grassland areas you want to restore in California, in the NEXT 30 days, mow and rake and remove any straw! That is because, any wildflower seedlings sprouting right now, need light and to not be suppressed by the allelochemicals being produced when rain hits the dry straw of the exotics. Stop the allelochemicals from killing wildflower seeds and seedlings--Because the killing and suppressing action of those allelochemicals is very rapid, in less than one week. I am putting together my 2024 Sunday-morning Kite Hill Wildflower Preserve "Wildflower Revival" Class schedule. Come and learn how monthly mowing at 8-12 inches high, and fertilizing can get rid of weeds like YELLOW STAR THISTLE and CHEATGRASS in 90 days without burning, grazing or herbicides, and very quickly restore wildflower meadows back to 95-98% native cover. Anyone interested, please send me an email for the class dates. Sincerely, Craig Carlton Dremann - [email protected] The Reveg Edge, P.O. Box 361, Redwood City, CA 94064