Tuesday, March 31, 2015

Early spring wildflowers part 1: Marion Sansom

Yucca and mexican buckeye on a limestone slope
Fredericksburg Division limestone
exposed, north end below dam
Most of Texas is afflicted with spring fever lately, its sweetness tempered by urgency because we know it cannot last. Any moment inside feels like a prison sentence. It is with this sentiment that I set about exploring Marion Sansom Park last weekend.

Marion Sansom Park is owned by the city of Fort Worth but has been adopted by the Fort Worth Mountain Bikers Association (FWMBA). These cyclists build and maintain the trails and signage. They are an enthusiastic presence on the trail, but I tend to move at a much slower pace. Especially when there's so much new stuff to see. The park itself borders the Lake Worth Dam, interesting because it looms near a limestone exposure in the Fredericksburg Division [1].

Lake Worth Dam, north side.
honey bee, mexican buckeye
The park is situated near the juncture of the western cross timbers and the grand prairie. This site, underlain by shallow limestone on a south-facing hillside, has a somewhat peculiar flora.
honey bee, redbud

I was most surprised to see mexican buckeye in abundance, which I had thought to be a more southern species. Mexican buckeye has pretty pink flowers and unique, pendulous tri-lobed fruits. The seeds, once released from their capsules, resemble rich brown marbles. I also saw blooming new jersey tea, redbud, plum, ten-petal anemone, prairie verbena, prairie parsley,  fringed puccoon, and coral honeysuckle.  The coral honeysuckle has emerged just in time for our returning hummingbirds, and it is one of their preferred nectar flowers.

A few coral honeysuckle flowers are already open
Mexican buckeye fruits
More butterflies are out too. Checkerspots, southern dogfaces, and swallowtails are now fanning about in addition to the familiar sulphurs and commas. I am almost certain I caught a glimpse of an early monarch gliding over my back garden.

The vertebrates were also out enjoying the weather. A coy green snake stuck his head out of a hollow tree to watch me walk down the trail, but retreated when I turned to take his picture. I had to wonder: how did he raise and lower himself so easily within his tree trunk? Is he braced against the walls, or does he have an interior shelf on which to rest?

It already felt warm on this southern exposure in the sunshine, and I was glad to wander the slopes of Marion Sansom in early spring. Last year we came close to 100 F by late April, and we are already projected to break into the 90s this week. Spring in Texas, like much of the rest of the world, is fleeting. I intend to get out in it as much as I can.

Cute green snake, peeping out of his front door.

1. http://northtexasfossils.com/geologytarrant24-39.htm

Sunday, March 22, 2015

The emerald city stinks

Oil and gas refinery? Or something else?
I've been thinking a lot about the future, in particular about how the world in which I retire will be different from the one I now inhabit. I'm at the point in my life where I'm seriously thinking about where I'll 'make my stand', buy a house, plant fruit trees... It's hard to plan for such things when you are very much aware that the world is changing, and you can't count on the place you settle staying the same over the coming decades. How do you put down roots when the Earth itself is shifting beneath your feet?

You may remember that I went to southeastern New Mexico over my winter vacation. High Country News recently published an article on oil and gas extraction titled "Lessons from boom and bust in New Mexico," which brought that trip back to mind. There, oil and gas exploitation dominates the landscape. There is no urban clutter to distract from the pump jacks and gas flares.  The night sky is orange from the natural gas burned off, relieving pressure on extraction equipment. The air stinks like cancer, and you drive past warning signs saying: "Danger: Toxic Fumes when lights flashing".

It's all your fault, car (not really).
Obviously, I was not so taken with the local industry as I was with the scenery. Oil and gas exploitation is one of those trades that is inherently extractive. Its nasty byproducts, and its contributions to our changing climate, make it an easy scapegoat. However, when communities have nothing else, how can you tell them not to mine the money stored in their shale piggy bank? Don't their kids deserve college as much as ours?

Additionally, one could argue that fossil fuels built Texas. Without oil, we'd be just another south central Ag state. Our economy might be more similar to that of Oklahoma. The Texas GDP, at $1.6 trillion, is second only to California in the United States. Our state's GDP is higher than that of Australia. This quick money does come at a public cost. Policy wonks call these "externalities." These costs are borne by those other than the organization which incurred them; and they include the poor air quality and increases in atmospheric carbon dioxide.

Climate Central's summer and winter projections for Fort Worth, year 2100
In a series of projections put out by http://www.climatecentral.org/, Fort Worth doesn't look quite uninhabitable by year 2100, but it's certainly less pleasant. Believe it or not, as hot as our summers get, the average temperature is only ~94F. We'll be adding ten degrees to that by the end of the century. This addition brings our temperatures to those of the Phoenix metro area, averaging 103F  (including nightly lows!). Indeed, our winters will warm too. Instead of 31 nights below freezing on average, we are likely to have only 8. I am tempted to console myself with "Well, at least I'll be able to grow avocados outdoors", but it isn't that simple. Changing global temperature averages shift the prevailing winds too. This changes precipitation regimes.

Projected precipitation changes (%) by year 2100
The map of projected precipitation shifts posted on the EPA's climate science hub suggests Texas will be drier, especially in the summers. Less rain + increased evapotranspiration (water lost to the atmosphere from plant exhalations and soil surface evaporation) is likely to shift our ecotype from Cross Timbers/Blackland Prairie into something much more arid. From our temperature projections, we could very well resemble the Sonoran desert. So: should we all plant saguaros and be done with it? While I'm tempted to move into an adobe with a cleverly crafted cistern system, there's still some hope. We could shift to renewable energy. Or perhaps we could hold industry accountable for its "externalities".

In a more basic, blind luck sense, precipitation changes are much harder to predict than temperature. While the scientific consensus is that the Earth will warm, the atmospheric eddies that determine rainfall are harder to model. You may notice that coastal areas are projected to increase in temperature more slowly than regions in the middle of the continent. This effect is due to buffering from the oceans. Water absorbs heat when it evaporates. Perhaps, if the air-stream shifts just so, we'll get enough moisture to prevent the "Arizonification" of Texas. Perhaps.

Don't be sad. Look at the pretty gypsum dunes!

Tuesday, March 17, 2015

Early spring at Copper Breaks

View from the edge of Bull Canyon, Copper Breaks State Park
Last weekend I took advantage of the warm weather and drove the 3 hours northwest to Copper Breaks State Park, 12 miles south of Quanah, Texas. Red dirt from the Permian has been cut and dissected into closed canyons and mesas. Thick cedars and brush on the interior of the canyon limit your line of sight. You feel so vulnerable to ambush. Of course, that could be me projecting my knowledge of the past onto the present. This canyon is within the Comanche heartland. Cynthia Ann Parker, one of the subjects of the popular book on Comanche history "Empire of the Summer Moon" was recaptured close to the park. Today the park is popular with families and youth groups. I wasn't the only one camping out last weekend.

Inside the canyon
The landscape is treed with juniper and mesquite. Mid-grasses grow well on the uplands, and they are dotted with cacti. Mormon tea (Ephedra antisyphilitica), pencil cactus (Cylindropuntia leptocaulis), and agarita (Mahonia trifolialata) are all more common here than further east. As you might guess from the latin name, mormon tea was once used as a treatment for syphilis. So many native plants have the species epithet "antisyphilitica" or "siphilitica", it makes me wonder about the prevalence of syphilis in North America pre-penicillin. I can think of three native plants off-hand that were used to treat syphilis specifically.
"Horse crippler" cactus
Anyway. I also saw the odd horse crippler cactus (Echinocactus texensis), so named because it hides semi-submerged in the dirt and is hard to spot. Supposedly, horses step on it. Looks like a deer knew to step around it. I'm a little skeptical as to how many horses have been crippled by this cactus. It makes me think about how in the upper Plains everyone's convinced horses are killing themselves by tripping on prairie dog burrows. Are they really so fragile? Does that really happen?

Blooming stretchberry sheltered by cedar
What I did not see was a ton of flowers. Spring is behind the metroplex in Copper Breaks. While our stretchberry (elbow bush, Forestiera pubescens) was blooming on Valentine's Day, theirs just started. I did see the standing dead stalks of gayfeather (Liatris spp.) and a number of composites, but very little new growth had been put on for the season.

Signs of life were mostly mammalian. Coyotes had heavily marked the trails with their scat, delineating the borders of their territory. When one of my neighbors at the campground fired up their grill (or other appliance…), it made a high-pitched keen and the coyotes were close enough to hear it and respond immediately. I also saw a rabbit out at dusk.

While it was early in the season, I did enjoy getting out somewhere nearby that looked so different from home. These little weekend trips help keep me grounded when I get to feeling desk-bound.

Sunday, March 8, 2015

Galls are a good thing*

*Or at least, mostly harmless.
Galls on an oak tree. Probably mealy oak gall (Disholcapsis cinerosa).
Lately, I feel like my blog's tagline could be "It's just aesthetics: leave well enough alone." First I defended mistletoe, then tent caterpillars, now gall wasps. I have noticed more oak galls in Texas than anywhere else I've lived. When I visited Dinosaur Valley State Park on Saturday, some trees were hung so thickly with them they looked like persimmon fruits. Others, which had supported leaf galls instead of twig galls, instead looked like they had odd round red acorns scattered about their trunks. You can get an idea for which critter created the gall by its appearance.

Gall wasps (Cnipidae) are the creatures that create the little brown orbs hanging in your oak trees. These cryptic creatures spend most of their lives as grubs. Adults are the size of a fruit fly and live about a week. They emerge, mate (every other generation), and then oviposit their eggs in stems, leaves, and twigs of oak trees all within that brief window. Note I didn't say "eat". Adult gall wasps don't eat- they live entirely of the plant matter they consumed as grubs inside their gall. They alternate generations between asexual females (who live in one type of gall), and sexually reproducing males and females (who live in another).
Another type of gall. Possibly Belonocnema kinseyi.
The galls themselves are an abnormal plant growth. They are not directly created by the wasps, but instead are similar to an immune effect in the host tree. There is consensus that this gall-making does not seem to hurt the host. The impact is so minuscule when weighed against the mass of the tree, it does not do measurable damage. I suppose it's like when you knick yourself shaving. You might bleed a little, but beyond the initial cut you don't suffer for it. I could not find a single source suggesting that galls harmed trees or required intervention. Most sources suggested doing nothing at all in response to an "infestation". The galls are not a danger, and they are only a problem if their untidy looks bother the homeowner.
A closer look at possible B. kinseyi galls.
Bizarrely, gall wasps are prevented from becoming super abundant because there are more trophic levels above them: they themselves are parasitized by a different kind of wasp.  Then, the wasp which parasitized the gall wasp is parasitized by ANOTHER kind of wasp. Nature just doesn't quit. It seems that being born a wasp is an awful tough way to make a living. An interesting effect this hyperparasitism has on the casual naturalist is that you have no idea if the bug which emerges from the gall is the one that built it. You could say that the gall structures the first wasps create serve as protective homes for many other insects. At a minimum, they provide an example of intense competition within the animal kingdom.

Sunday, March 1, 2015

Iced in again

Yep, those are all wrecks
On friday I drove home through some of the gnarliest traffic the metroplex has seen this winter. It was bad enough to make the national news. By the time I was on the roads, most of the wrecks had already happened but had not been cleared. Abandoned cars facing the wrong direction lined the interstates. It looked apocalyptic. The few of us out trying to get somewhere were hitting top speeds of 20 mph. I wouldn't have tried it, but I was heading home from a meeting in Austin so I could pick up my dog from daycare and return a rental car. I knew all these tasks would be much harder the next day.

I tried to get out again on Saturday, and I made it a block before I slipped into a skid on a downhill and came to a gentle stop wedged against the curb. I was totally unharmed and rather lucky to be within an easy walk of my house, but I felt foolish for letting my cabin fever get the better of me. It was so slippery I couldn't even walk-- one of my neighbors came out to offer me a hand leaving the ice patch. I was slowly sliding downhill in my snow boots. He seemed skeptical when I said I was fine and could make it home on my own. I guess I was so fired up to get out because I haven't really gone walking in a couple weeks and it's been wet and cold. I appreciate the snow and ice for recharging the aquifer, but I miss going outside.
View of my backyard
I did get to see a little nature in Austin, however. I went to an amazing nursery called "East Austin Succulents" to peruse their collection of weird plants. I ended up taking two home, a split rock plant and a rattlesnake tail Crassula columella, both native to the South African Karoo. So cool. I'd love to tour the Karoo someday.  I adore botanical oddities.
Two new friends. 
I also saw some diminutive native wildlife. A moth sheltered from the cold under a blade of agave in the outdoor portion of the nursery. Thanks to the "Mothing and Moth Watching" Facebook group, this fluffy little guy was ID'd as a Hyphantria cunea, or Fall Webworm Moth. He looks quite stylish to my eyes-- I admire his fuzzy stole and leopard-spotted wings.
A male fall webworm moth
Fashionable as he may be, the fall webworm moth is a pest to many horticulturalists. They are called "webworms" because their caterpillars graze socially within a silk tent on branches. The netting lessens predation. Their caterpillars tend to prefer broadleaf trees, and in Texas they favor pecans. Like many other pests, their damage is mostly cosmetic. Even complete defoliation by webworms is unlikely to seriously harm a tree. It's just unsightly. Though it was certainly too cold for this moth to fly (many insects are unable to fly at temperatures below 55F), late february is not excessively early for these fellas to emerge.  

Fall webworm moths are native to most of North America, and they have invaded eastern europe and asia. Apparently they were accidentally introduced in Yugoslavia in the 40s, and they expanded from there. I feel a little vindicated, because there are few other non-native insect pests you hear about colonizing in that direction. While they are not a major problem in the States, I'd be interested to hear whether they are harder on the ecosystem outside their native range.  Considering that we live in a world with truly catastrophic invasive pests, I have trouble taking a little aesthetic damage seriously. I hope that's something horticulturalists consider when creating a management plan for this little moth.