Thursday, October 23, 2014

The Ethics of Seed Collection

Nice, unharvested seeds.
I am passionate about native plants. I’m quite serious- it has been years since I intentionally introduced a non-native plant to my yard (other than vegetables, of course). Naturally, I jumped at the chance to get involved when my work gave me the ‘go-ahead’ to help with native seed sourcing. However, seed collection is not so simple as “find, harvest, propagate”. Many native plants have suffered population declines from over-collection, so it is important to take steps to ensure an ethical harvest.

Ginseng, orchids, carnivorous plants, echinacea, black cohosh, golden seal, and galax have all suffered from over collection. What do these plants have in common? They are the medicinal, the rare, and the weird. This damage is nothing to be sniffed at. Galax is harvested for its value in floral arrangements. The majority of galax stands along the Blue Ridge Parkway in the Southern Appalachians were targeted by poachers in 2012 [2].  Even worse, plants like ginseng, echinacea, and black cohosh are entirely destroyed by harvest, as the root is the part of the plant consumed. Others, like orchids and carnivorous plants, are delicate and often do not survive transplanting in their new environs anyway.

Someone may have beat me to it.
Or was it the wind?
Declines in medicinal plants have been well studied. Ginseng is a famous example. Recently, a ranking criterion was created to estimate the vulnerability of a plant to over collection. Traits on this list included: life history (i.e., how long does it take to reach maturity, what is its reproductive rate), effect of harvest (is the plant killed when harvested), population size, habitat, and demand [1]. To avoid over collecting, one should limit the amount of seed collected from a population, and not collect from the same site year after year. There isn’t a consensus on exactly how much seed you can collect from a population without causing harm. Some sources say no more than a third, others say 10%, and others yet say 5% per year over 10 years. I am sure that the exact details of a ‘safe collection rate’ vary by species, population size, and location. Generally agreed upon exceptions to these guidelines are in the case of plant salvage—where plants are removed from a site prior to its destruction or development. In this case, 100% harvest is acceptable.

In addition to calibrating your harvest level against the possibility of causing real damage to the landscape, one must consider legality. Obviously it is illegal to collect protected species. It is also illegal to collect in most State and National Parks. Often one can collect on Forest Service or BLM land, but this typically comes with restrictions and requires the purchase of a permit for a small fee. Collecting on private land is OK with permission as long as the target plant is not protected. Roadsides are something of a toss-up—most seed collectors (including myself) believe road sides to be fair game. However, if someone requested that I stop collecting from along their property, I certainly would.

Restored crop-field prairie
Somehow, while juggling all these factors, I have managed to harvest from two sites. One was a roadway in Denton County.  The other was a private prairie north of Temple. My harvest protocol in Denton was pretty clear-cut. Unless someone stopped me, I would be able to collect seed. Additionally, the roadsides had been mowed and most of the seed heads shattered, so I wasn’t too worried about over collecting. I probably couldn’t have collected more than 5% of the seed produced even if that had been my intent.

The second site, the private prairie, was a little fuzzier. While I made sure to get permission prior to collection, once I arrived on site it became clear to me that someone had already harvested some seeds from the target species earlier in the year. A few stalks had legible cut marks on them, while others did not. So the question became: how much could I take sustainably? How much seed had there been before the previous collector came?

After doing some looking around I decided that the original collectors had not taken much, and had collected from a central location along a mown path. Most of the bare stalks outside that area had a few seeds still hanging off them, suggesting that they had been shattered and scattered by non-human means. The plants that still held their seed were lower and had not been so exposed to the wind. I fretted some, and I never did settle on an exact amount that it would be OK to collect, but I did the best I could. I am comforted that, someday, the descendants of this foundation seed will be used for prairie restoration and will support many pollinators and other wildlife.


1.     Castle, L. M., Leopold, S., Craft, R., & Kindscher, K. (2014). Ranking Tool Created for Medicinal Plants at Risk of Being Overharvested in the Wild. Ethnobiology Letters, 5, 77-88.


Sunday, October 19, 2014

Halloween in the Cross Timbers: The Legend of Goatman's Bridge

Graffiti on Old Alton Bridge

To me, halloween is an excuse to indulge in creepy ghost stories and, frankly, morbid curiosity.  For this reason I took my dog on a special excursion up to the eastern Cross Timbers in Denton County. We were going to see the Goatman's Bridge. 

Colby ain't afraid of no goats
Old Alton Bridge is the setting for one of the more widely circulated local ghost stories. Built in 1884, this single lane truss bridge was still in automotive use up to 2001, when it was replaced by a steel and concrete construction that straightened the sharp curve in the road crossing Hickory Creek [1]. Evidently, up until the bridge was replaced, you'd essentially honk and pray for attentive oncoming traffic while roaring across in your car. Now it has been retired from heavy traffic and instead serves as the link between the Pilot Knoll and Elm Fork horse and foot paths. 

There are conflicting reports of the origin of this bridge's specter. Most versions of the story say that a successful goatherd named Oscar Washburn was lynched from the bridge by the Klan in 1938. The klansmen found the noose empty after throwing Oscar over the edge. Enraged by his presumed escape, they crossed the bridge and slaughtered the man's wife and children. Legend has it that if you cross the bridge after dark you'll see the glowing red eyes of a demonic satyr menacing you from the other side. The Goatman is hunting the klansmen who murdered his family, and those descended from the klansmen are cursed to be hunted unto death.

Fortunately, there seem to be no historic records of an Oscar Washburn or of a lynching from the bridge. While there was racially motivated violence in the surrounding area at the time, Oscar Washburn and the Goatman seem to be nothing but a cipher standing in for the guilt felt for all those unjustly persecuted during the racial tensions of the 30s [2].

Another entity also said to reside in the haunted forest resembles the Mexican legend of "La Llorona", the weeping woman who haunts rivers, steals lost children (especially those that disobey their parents!), and marks for death all who hear her. As is so often the case, ruffians attracted by the dark stories cause more trouble than any ill-tempered apparition. The area near the bridge is littered with empty shotgun shells, blown out signs, and broken glass. The local Master Naturalist group has a standing clean-up date on November 1st, putting the park back in order after the unauthorized Halloween night festivities. 

Small red arrow pointing to sneaky clump of sericea
established along the trial. Grr. 
I did encounter one menacing presence along the trail: Lespedeza cuneata, aka sericea lespedeza, scourge of rangelands and forests throughout much of North America. This invasive, perennial legume is not supposed to occur in Denton County (yet), (see comments section) but there it was, making in-roads along the horse trail. This (ob)noxious weed is a prolific seeder and can rapidly crowd out every other plant in a stand. Single ramets (stems) can produce 1,500 seeds per year, and cultivated stands can yield up to 300 million seeds per acre [3]. One is truly sickened when considering the person-hours and herbicides dedicated to the control of this aggressive species. 

Today the park winds through dry meadows surrounded by scrubby post-oak, cedar elm, hickory, and hackberry forests.  It's early autumn in the eastern Cross Timbers, and heath aster, goldenrod, sneezeweed, eryngo, partridge pea, broomweed, and agalinis still bloom. Mothers were taking halloween-themed pictures of their small children on the bridge. It's a little macabre when  one considers that the bridge is famous for an apocryphal lynching. 

I have low expectations for this buckeye's longevity
Despite this, Colby and I had an altogether pleasant walk along this historic path. While we didn't see any satyrs or weeping women, we did see skippers, sulfurs, buckeyes, a red admiral, and tardy monarchs that were flitting around the meadows and low canopy.  Mercifully (?), Colby only cared to snap her jaws at the skippers and sulfurs that were fully capable of evading her, showing no interest in a largely incapacitated buckeye we found resting on the trail. I suppose it wouldn't have been "sporting" to pursue already downed prey. We both have an interest in bugs, after a fashion.

I only walked the first few miles of Elm Fork trail. There are many more miles and trails to explore [4]. Perhaps someday I shall come back to view more of these well-used paths-- during the daytime, of course.

Hickory Creek and Old Alton Bridge

Virginia creeper begins to senesce 


Saturday, October 11, 2014

The Singular Flint Hills

Ironweed does well first year after a burn in the Tallgrass Prairie Preserve
I have been feeling the absence of a major camping trip this summer, so I’ve been stealing the odd night sleeping out when I can. A few weeks ago I was in the Kansas Flint Hills for work, and I took my tent. I camped in my rancher-host’s backyard instead of crashing on a couch or in a hotel. This may present a funny image to those of us in the suburbs, perhaps conjuring a childhood sleep-over with friends and visits from mom and dad with treats and bedtime stories. However, when you’re in the Flint Hills and your host owns a mile in every direction, camping is a little more enticing.

House under the stars
The coyotes seemed somewhat muted by the new moon. The first morning they howled at the sunrise. The second night, after violent passing storms, they slept late and only started yodeling to each other around 8:30 am. I wonder where they hunker down, and if they can stay dry, during the storms on the Great Plains. My old tent did fine- the seams do need to be re-taped, but any water that seeped in pooled up like a moat around the edges. I stayed high and dry on my closed-cell foam sleeping pad.

The dark moon made for an excellent showing of the Milky Way. It looked like a band of thin, high fog across the sky. I was inspired to attempt nighttime photography for the first time. I had guessed that the stars would be spectacular in Kansas, so I brought my tripod and remote shutter control. This won’t be last time I try to capture a starry night-- two state parks and one national park in Texas (Copper Breaks, Enchanted Rock State Natural Area, and Big Bend National Park) have been designated “Dark Sky Parks” by the International Dark Sky Association. Both state parks are less than a four-hour drive from Fort Worth. For reference, there are only 14 certified Dark Sky Parks in the entire United States.

Stars over Kansas
I was in Kansas to view some sites where cattle grazing had been well balanced with biodiversity conservation. To this end, I visited the Tallgrass Prairie Preserve and a private ranch in the Flint Hills. The Flint Hills are an amazing pocket of semi-natural grassland in an otherwise cropped region. The ‘flinty’, fossiliferous limestone accretions, from which the Hills get their name, made these rolling plains simply too much effort to farm. Unlike much of the surrounding region, the Flint Hills never submitted to the moldboard plow. Grazing rules the economy here.

Fossil I found on my host's ranch
Most local ranchers burn their pastures every spring to freshen the grass for their cattle. The historic fire regime was probably closer to 3 to 6 years, but it’s difficult to say if the accelerated fire regime is good or bad on the balance. Annual burning can lead to erosion, homogeneity, and ‘pedestalling’, where soil around bunch grasses washes away, leaving the bunches on an elevated base (or ‘pedestal’). On the other hand, annual burning has allowed the Flint Hills to largely retain its open, blue-sky character in the face of widespread woody shrub encroachment. Personally, because so much of the tallgrass prairie has succumbed to woody encroachment, I think I may prefer annual burning to no burning at all, if those are the only choices. Both can be hard on a landscape, but at least annual burning keeps some land open.
Wind in the goldenrod

Overall, the Flint Hills look good. The grassy, rolling hills reminded me of a gigantic alpine meadow—which is logical, I suppose, as it is a gigantic (sub) alpine meadow. ‘Sub’ in the sense of ‘lower than’. The Tallgrass Prairie Preserve even has the novelty of bison. While it is arguably ‘understocked’ in that there are only 30 bison grazing a 1,100 acre pasture (TGPP has ~11,000 acres total), it is lovely. I’ve heard rumors that they aim to build their herd. Because they desire genetically ‘pure’ bison- bison that are uncontaminated by the cattle genome- they have had some trouble getting their hands on these high-demand livestock. Or should they be called wildlife? I suppose that’s a question for another time. 

Skeptical bison look on from the bluff

Tuesday, October 7, 2014

Peak Monarch 2014

Monarch sharing a pitcher sage plant with a bumble bee
This week we're hitting "peak monarch" in Fort Worth. According to Monarch Watch estimates, tomorrow is the midpoint of the height of monarch butterfly abundance for Fort Worth's fall migration [1]. I'd actually noticed the up swell in the population over the past week, especially after Thursday's passing storm. Every time I looked up I'd see at least one monarch flapping hard to the south, sometimes as many as three. It makes sense to me that they would follow the fronts. They do, after all, ride the wind. The last of this year's monarchs should finish passing through by November.

Monarch Fall Migration, from USFS pollinator site [2]
Texas is the funnel through which many migrating monarchs pass on the way to their Mexican wintering grounds. While most people are aware that monarchs migrate south to avoid our North American winters, I still find the flip side of this equation shocking: they must recolonize their entire range every year. Instead of overwintering in the litter and duff, brave monarch parents must fly the length of a continent.

Unlike the Methuselah-monarchs bent on the southern horizon in the fall, the spring migration requires multiple lifetimes [2]. They drift northward over 3 or 4 generations.  It appears to be these shorter lived summer monarchs that are the sink of the decreasing monarch brood. For years people blamed declining populations on habitat loss in the monarch wintering roosts in Mexican forests. Recent studies suggest that it is actually the Midwest's ultra-efficient weed control in the summer breeding grounds that is at the root of the decline. Monarchs simply can't find enough milkweed on which to lay their eggs.

Asclepias asperula, antelope horns/spider milkweed
In addition to being the last stop on their way south, Texas is their first stop on the way north to summer pastures. Increasing the abundance of milkweeds in Texas could be hugely beneficial to these amazing creatures. There are over 30 species of milkweed which can be found in Texas [5]. You can find range maps of the milkweeds (Asclepias spp) at the BONAP (The Biota of North America Program North American Vascular Flora) website [3]. In my neighborhood, I tend to see Asclepias asperula, A. viridiflora, and A. viridis. All three species are documented larval hosts to monarchs. 'Documented larval host' means monarch caterpillars have been officially observed and recorded feeding on these plants [4, see appendix for list of milkweeds]. Milkweeds you may find in north central Texas include [3]:

A. amplexicaulis*
A. arenaria
A. asperula*
A. engelmanniana
A. latifolia
A. linearis (likely endemic to Texas)
A. longifolia*
A. obovata
A. oenotheroides*
A. perennis*
A. stenophylla
A. subverticillata*
A. texana (endemic to Texas)
A. tomentosa*
A. tuberosa*
A. variegata*
A. verticillata*
A. viridiflora*
A. viridis*

* denotes documented larval host to monarch caterpillars [4]

It is possible that some of the milkweeds that have not been documented as larval host plants have successfully nourished monarch brood. Some, like the Texas endemic Asclepias texana, are relatively uncommon and are less likely to be observed, period. I'm a bit of a plant collector so I'm going to try to get my hands on some native milkweed seed to sow this winter. In the spring, after receiving the cold/moist stratification they require in my fallow garden, these seeds should emerge and start my monarch buffet. Eventually my plants will provide high-quality nectar to monarch butterflies on their way north, and leafy lunches to little monarch caterpillars beefing up for their transformation and long journey.

As an FYI to any North Texas readers: this week is the Fort Worth Botanic Garden's fall plant sale. I have not confirmed that they will be selling milkweed, but considering their focus on native plants and insects I think it is fairly likely. The plant sale starts the evening of Friday, October 9th and goes through October 11th. You can find more information here.

Good bye monarchs, at least until March next year!