Wissahickon Part 1: Houston Meadows

Bumblebee on goldenrod

Last Saturday (October 15) was an absolutely perfect early autumn day, with temperatures in the upper 60s, crystal clear blue skies, and very low humidity.  I packed Kali into the car and we drove over to the north-westernmost neighborhood in Philadelphia called Roxborough for a hike in the 1,800-acre Wissahickon Valley Park, Philadelphia's largest and best-known park.  Our goal that day, in addition to just getting some exercise, was to inspect Houston Meadows, a restoration project undertaken by the city's Department of Parks and Recreation as part of an ongoing series of natural lands restorations throughout the city's larger parks.

Trail through goldenrod and little bluestem

A few aspens; there are others growing nearby at the edge of the meadow

Native little bluestem (Schizachyrium scoparium)

To my mind, the Houston Meadows project was not a straightforward "winner."  During the early part of the 20th century, the meadows had been an active farm before urbanization expanded outward to the very edges of the city limits.  When the farm was incorporated into the park, the land became fallow and quickly reverted to herbaceous old-field habitat - a "wildflower meadow" in common parlance.  This habitat was extraordinarily attractive to birds and butterflies that needed such habitat, and Houston Meadows became a birders paradise maintained by fires set periodically by neighborhood hoodlums.

Bluebird box on meadow slope

All was well until houses were built up to the very edge of the park, and then the field fires had to be suppressed.  This fire suppression allowed natural succession to kick in and trees and woody vegetation, formerly killed by the fires, began to creep into the meadows, changing the land first to a thicket and then to a young woodland.  The birds and lepidopterans could no longer find appropriate habitat and abandoned Houston "Meadows."

Goldenrod (Solidago spp.), boneset (Eupatroium perfoliatum) and native grasses

With support from a philanthropic foundation, the city decided to try to restore the meadow habitat and attract the birds back.  So, they brought in heavy equipment to clear the trees in the young woodlands, and they seeded the land with early concessional meadow species and native grasses.    

The result has been mixed in my opinion.  First, I have to admit that I don't know if the "target" birds have returned to the meadows.  If they have, they've "voted with their wings" and given the restoration their approval.  But, if the birds haven't returned, the project cannot automatically be dubbed a failure because (1) they birds may not have "found" the meadows yet, (2) the habitat may not have developed enough to interest the birds, or (3) the restored field really might not be suitable habitat.

This section of the meadows almost looks "western," with a big rock and conifers

Where the herbaceous vegetation has gotten established, the meadows are lush, productive and beautiful.  But Parks and Recreation seems (to me, anyway) to have left too many trees in the midst of the fields.  Hawks and other raptors perch in these trees and prey on the meadow-nesting birds.

In addition, the meadows are small and fragmented.  Some meadow-nesting birds seem to need 160 acres of grassland habitat to breed successfully, and these fields are nowhere near that large.  Other species, especially species that like brushy habitat, may be the first ones to recolonize the site.  To my eye, the habitat looks perfect for birds that like scrubby, brushy habitat.

Deer exclosure fencing

Parks and Recreation also included a deer exclosure as part of the project, but it is in a wooded corner of the meadows.  I don't know the motivation for excluding deer from a meadow project, but perhaps they were trying to expand a section of woodland and not develop meadow here.

Late Summer

Sunset thunderhead

I know that I've been very negligent in posting, but truth to tell, Kali and I really haven't been doing much of anything that's worth writing about.  The last few weeks have been miserably hot and humid, so we haven't even ventured out onto the trails of my preserve let alone go anywhere else.

Long shadows

However, the seemingly unending heat wave finally broke on Sunday evening with a round of rain that ushered in the passage of a real, live cold front.  On Monday, the humidity was pleasant and temperatures rose only into the low 80s (instead of the mid- to upper 90s we had been suffering through).

The birds missed a few ripe black cherries

A friend posted on Facebook that he had participated in a nighthawk watch in a state park not far from my preserve and had seen 25 Common Nighthawks - one of my favorite birds and a sure harbinger of autumn when they begin to pass through on their way southward.  So, after dinner last night, to enjoy the salubrious weather and to look for migrating nighthawks, I got Kali to lace up her walking shoes and take a short hike through our late summer meadows.

At one point, the setting sun was shining directly through some of the meadow grasses and thistles, so I thought I'd make some "artistic" shots.  The following two images were the result; I boosted-up the contrast on both images a lot, so they're not strictly what the camera "saw."  I'm not sure if I like the result, but I thought I'd share them. 

Thistle, backlit

Indian-grass flower head, backlit

We didn't see any nighthawks (I usually see them during the last week of August and the first week of September, so if we had seen them, they would have been early).   But we did enjoy our first walk in the preserve in quite a few days.  I'll go out again this evening in search of nighthawks because the weather is still delightful.

Kali, heading home

Field Trip Sampler

U.S. Fish and Wildlife biologist with a rare bird

Last weekend (March 26-28), I attended the Society for Ecological Restoration Mid-Atlantic Chapter's 10th Annual Conference at the University of Delaware in Newark, Delaware.  (For those not "in the know," never pronounce Newark, Delaware like Newark, New Jersey.  The New Jersey city is pronounced NEW-erk, whereas the Delaware city is pronounced new-WARK.)  Following a Thursday evening dinner at which I and eight colleagues were feted as founders of the chapter, the group re-convened the following morning for a day of formal presentations.  On Saturday, I participated in a field trip of three restoration sites within a half-hour's drive of the university.

Saturday was mostly cloudy, cold (high of 40 degrees F in the afternoon) and windy.  As we waited for the bus to depart, the group endured snow squalls.

Northern Delaware is DuPont territory.  Many of the wealthy heirs of the DuPont chemical fortune established expansive estates in the rolling hills of Delaware's Piedmont west of Wilmington, and some of these were sites we visited.  Our first stop was Mt. Cuba, a 500-acre estate that has been turned into a botanic garden featuring plants native to the Piedmont.  The 50 acres surrounding the mansion are a horticultural showplace and are beautifully maintained, but the remainder of the property (the part our group visited) faces the same challenges I face at my preserve: overabundant deer, invasive plants, and stream flooding. 

Nathan Shampine, Mt. Cuba's natural lands manager, indicating that deer could gain access to this fenced exclosure

The golden rolling hills of northern Delaware's Piedmont in early spring

A Red-winged Blackbird's epaulet (Agelaius phoeniceus) found on the ground

Our second stop was the Delaware Nature Society's Coverdale Farm and Burrow's Run preserves.  At Coverdale Farm, we explored a wetland restoration project in which a wet cattle pasture formerly drained by terracotta tile pipes had been reflooded (by removing and breaking the pipes) in order to provide habitat for federally endangered bog turtles (Clemmys muhlenbergii).

The wetland created by re-flooding the field--a sedge hammock marsh

The re-engineered outlet from the marsh (still a bit raw)

Our group continued walking to the adjacent Burrow's Run Preserve, where the Delaware Nature Society has been converting pastures to native grasslands for grassland-nesting birds.  I literally was in awe and very jealous of their best fields, pictured below.  These fields support moderate growth of little bluestem grass (Schizachyrium scoparium) interspersed with dozens of species of forbs (i.e., wildflowers) - exactly the type of habitat meadow-nesting birds are seeking.  The grasses provide cover and the forbs attract insects for the birds to eat.  The fields at my preserve, in contract, are almost exclusively grassy with few forbs, which is why we haven't had luck attracting birds to my fields.

Beautiful native meadows

Queen Anne's Lace (not native) against gray skies

Our last stop was the Flintwoods Preserve, a 157-acre private (DuPont heir) estate whose claim to fame is a stand of ancient forest.  Our group, however, toured the native grassland restoration projects underway in the old agricultural fields on the property.

A renovated barn on the Flintwoods estate

We parked our bus next to a renovated barn on the estate.  The barn is full of vintage baroque harpsichords that Peter Flint is in the process of restoring.  The Flints host sold-out baroque music concerts in the barn several times each year.

Flintwoods' land manager explaining how he intends to modify his management plan for his grasslands this year

A humorous aside: as we were returning to the university following the field trip, driving through the northern Delaware countryside sprinkled with DuPont properties, one of the fellows on the bus quipped, "I keep looking at all these houses and imagining sexually-charged wrestling matches going on in each one." (a reference to last year's film Foxcatcher).  Of course, after he said that, I couldn't look at the places the same way myself! 

Regrouping on Meadow-nesting Bird Habitat

Between a pasture and a crop circle

Since 1997, our organization has been working diligently to create habitat for meadow-nesting birds which, as a group, are the most endangered suite of birds on the East Coast because of habitat loss.  Our strategy has been to establish native, warm-season grasses on a 160-acre farm we purchased that year.  Now nearly two decades into the project, we have a fairly respectable stand of native "prairie" grasses cloaking the land.  The grasses are beautiful (especially this time of year), resilient, and very popular with our visitors - but not with the birds we are trying to attract.  Eastern Meadowlarks, Bobolinks, and several species of sparrows stop in the grasslands during migration, but they never stay to breed.  What's wrong?  Didn't we do everything right?

Well, it turns out we didn't do everything right.  Grassland managers all along the East Coast have come to realize that the birds are seeking diversity - diversity in height and diversity in plant composition.  To the birds, our grasslands are too dense, too tall, and too monotonous, and they don't provide food (i.e., insects) in sufficient quantities for nestlings.

So, you might recommend that we diversify the grasslands, and you'd be right.  However, we also have a terrible problem with invasive plants.  The grasses can be treated with special herbicides that kill all invasive plants except the grasses, but there's no such "magic bullet" for diverse combinations of plants.  Once invasive plants colonize a mixed-vegetation meadow, control becomes much more time consuming and costly because the invasive plants have to be removed "surgically" without disturbing the desirable plants.  We've resisted trying to diversify our grasslands for that reason.

But, we've finally come to the realization that (1) we're not going to attract meadow-nesting birds if we don't do something different, and (2) if we can't attract meadow-nesting birds, why have the grasses at all because our landscape really wants to be a forest and we have to fight Mother Nature (i.e., natural succession) to keep it in grassland.

Fortuitously, I invited a respected field ecologist to speak to my restoration ecology class a few weeks ago about native grasslands.  This ecologist and I are good friends, and he has visited my preserve to consult on several occasions.  He also serves on the board of directors of another land trust in the region.  He told me that "his" land trust had had Eastern Meadowlarks nesting in native grasslands this summer, and he suggested that I talk to his land manager for some guidance.  So, I rounded-up my senior stewardship staff for a field trip and we paid a visit to the other land trust on October 30.  

Edge of the "crop circle" (darker foreground), native grassland (tawny center) and pasture (green, far left)

Tom, the preserve's land manager had successfully created native grasslands like we had, but had also failed to attract meadow-nesting birds.  Then, he decided to create "crop circles" - round meadows within the grasslands that he seeded with a mixture of 16 different species of low-growing flowering plants (i.e., wildflowers).  Three years ago, he established about 10 such circles ranging in size from 0.25-acre to over 4 acres.  And, this summer, Eastern Meadowlarks nested in his preserve - not in the crop circles (and not in the native grasses), but in a pasture composed of non-native grasses immediately adjacent to the largest crop circle.  

Diverse crop circle vegetation (foreground)

Tom watched the meadowlarks build nests in the pasture (which is just as monotonous a monoculture as the native grasslands, but lower in height).  Then he watched the adult birds fly into the crop circle to catch insects that were using the wildflowers.  Success!

Crop circle (foreground), native grasslands (mid-ground), and woodland (background)

Tom's crop circles get colonized by the same invasive plant species with which we have to contend, but he told us that he is able to control the invasives before they become problematic with a combination of mowing before the invaders set seed, spot application of herbicide, and the judicious use of a string trimmer.  He's got a smaller land stewardship staff than I do, so my staff should be able to do as well.

Crop circle (right) and native grassland (left)

My staff drew-up plans for our grassland modifications in the car on the way back to my preserve.  Stay tuned; it may be a year or two before we're successful, but at least we now have a plan!

Autumn color in the grasslands

Sunset Medow Ramble

On Tuesday evening, I had a chance to walk the native grasslands in my preserve just as the sun was setting.  The sky was dramatic, and the lighting was interesting, though barely bright enough to show the colors that are developing in the meadows and the woods.

The natural area preserve surrounds me every day, but the only time I get out into "nature" is after work and on weekends.  Otherwise, I'm mostly "chained" to my desk.  One of my board members warned me this would happen when I was promoted from land manager to executive director; he was prescient.

Sora Out of Water

Sora (Porzana carolina) [Image from an Internet source]

This morning, two of my preserve's best birders and nature photographers stopped in the office after a morning photo shoot to report that they had found and rescued a Sora (Porzana carolina) on a trail through our tall native grasslands.  The Sora was alive (though clearly injured or sick); the birders planned to take it to a wildlife rehabilitation facility to see if it could be saved.

Two years ago, a birder found a Sora on another of our grassland trails, but that bird was dead. 

I have no idea why a fairly uncommon bird almost always associated with marshes would be found high and dry in the prairie-like grasslands we have established on parts of our preserve.  Nor do I have any idea why these birds are in bad shape.  It's great that they're here, but not if our preserve is acting as a "sink" in which the birds fall victim to predators or disease. 

Frosty November Morn

 

I awoke on Saturday morning (November 9) to beautifully frosted native grasslands adjacent to my house.  I did my best to capture the crispness before the rapidly rising sun dispelled the magic.

Weedy, non-native foxtail (Setaria spp.) in front of tawny Indian-grass (Sorghastrum nutans)

Rimed thistle rosette and oak leaf

Golden August Prairie

 

We've established native grasslands on 160 acres of old hayfields in the preserve.  Most of the grasslands are just that--grasslands--dominated by big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium) and Indian-grass (Sorghastrum nutans).  But we also incorporated wildflowers into 60 acres of the grasslands, and right now these meadows are in their late-summer glory.

Because our fields are subject to intense invasive plant pressure, we decided to concentrate on planting grasses only on most of the land.  We restricted our planting to grasses because we could use the selective herbicide Plateau on these grasslands.  Plateau controls broadleaved invasive species like non-native porcelain-berry (Ampelopsis brevipedunculata), Asian bittersweet (Celastrus orbiculatus) and Canada thistle (Cirsium arvense) plus aggressive natives like brambles (Rubus spp.), but won't damage the native grasses.

However, our grassland manager determined that there are a few native broadleaved wildflower species that aren't harmed by an application of Plateau.  So, we incorporated seeds of some of these species into 60 of the the most recently established acres.  These meadows now offer a mixture of grasses and forbs not present elsewhere in the prairies.  And, the wildflowers enliven the the grasslands with big swaths of color, making a walk on the trail winding through the meadows a real delight this time of year.  Bright yellow partridge-pea (Chamaecrista fasiculata) is blooming profusely now, along with a few remaining black-eyed-susans (Rudbeckia hirta) and a delicate white-flowered aster (Aster sp.) that I haven't tried to identify yet.  Of course, the fields are literally abuzz and achirp with every sort of hymenopteran, lepidopteran and orthopteran imaginable.

 Purpletop (in foreground) growing mixed with partridge-pea and little and big bluestem

We're also enjoying a real unanticipated surprise in these meadows, too.  Though we didn't plant it, purpletop (Tridens flavus) has become a very common grass throughout these fields.  Where it grows densely, purpletop's delicate flowers spread an enchanting mauve gauze over the landscape. 

 

Glorious Early Fall Field Trip

Autumn dogwood as stained glass

I'm teaching a graduate course in restoration ecology this term, and brought the students to my natural area to give them some first-hand experience with state of the art restoration techniques and land management strategies in a natural area that is subject to considerable pressure from white-tailed deer and from invasive plants. Many of the students are landscape architecture candidates, so they need some exposure to native ecosystems, not just design classes.

The day was absolutely perfect--temperatures in the mid 70s, low humidity, and billowy white clouds sailing across an azure sky.

The native grasslands are at their peak right now, especially where they contain goldenrod and white snakeroot. The meadows are just gorgeous!

Back at the nature center, white wood aster was blooming in the shade of a specimen tree alongside a white picket fence.