Showing posts with label drought. Show all posts

May 8, 2014

Our drought continues, despite three-quarters of an inch of hard, thunder-scented rain today about noontime. The Creek is no longer a continuous flow from the hills of Burnet down to the Colorado River, but the Pond remains spring-fed, even if it doesn't flow out above ground into our part of the Creek. The image directly below shows looking down-stream across dry-bones of a stream, with American water-willow (Justicia americana) blossoming white, with rabbit-foot grass (Polypogon monspeliensis) lush and soft to the eye, and with our own devil's yellow-hair in disguise--Dodder (Cuscuta japonica)--sucking away the liquid nutrients of whatever plant it can strangle (the small bit of gold in the center of the image below and then above the Creek about half a dozen photos farther down this page).

I find the image below interesting if only because of the story it's telling of a hillside turned gray from our really bad drought and heatwave a few years ago; of a greenhouse roof; of a stone-field filling in with grasses; of young sycamores boldly rising up since the flood tore out the others about six years ago; and the much-reduced Creek of today.

Here are some water-willows with a bit of stream passing through:

History book.

After the storm blew through today, I found this pair of painted buntings (Passerina ciris) dead beneath one of our home's south windows against which they presumably found that the reflection of lights and leaves was solid. They were only a foot and a half apart from one another. I've been seeing a pair of buntings flying around our yard for the past week.

The French name for this bird is nonpareil, meaning "without equal."

Gay Damselflies and Hoses Up a Hillside

From out of the Pond, water pumps up the hillside.

Three (3 1/2?) pairs of damselfly doing their thing near our submerged water pipe.

So the following excerpt was too good not to reproduce again here:

Damselfly Mating Game Turns Some Males Gay

James Owen
for National Geographic News

June 21, 2005

Disguises used by female damselflies to avoid unwanted sexual advances can cause males to seek out their own sex, a new study suggests.

Belgian researchers investigated why male damselflies often try to mate with each other. The scientists say the reason could lie with females that adopt a range of appearances to throw potential mates off their scent. In an evolutionary battle of the sexes, males become attracted to a range of different looks, with some actually preferring a more masculine appearance.

The study, published recently in the journal Biology Letters, says such evolutionary selection pressures could also explain homosexual behavior seen in males of other animals whose females assume a variety of guises. Such "polymorphic" species are seen in dragonflies, butterflies, hummingbirds, and lizards.

Female blue-tailed damselflies (Ischnura elegans) assume different color forms, or morphs, in adulthood: green-brown, yellow-brown, and blue. The blue form closely matches the male in both body coloration and pattern.

The study team found the sexual preference of male damselflies was influenced by the company they keep. Males that were housed together before being introduced to females tended to seek out their own gender afterward. But males kept in mixed-sex living quarters later preferred all three female forms when choosing a mate.

This suggests male damselflies are likely to become attracted to other males only when females are absent or scarce. Yet a minority of males still showed an innate preference for male mates.

The team's findings were reflected in mating behavior observed in the wild, says study author Hans Van Gossum, an evolutionary biologist at the University of Antwerp, Belgium.

Van Gossum says around 17 percent of males in wild populations appear to favor same-sex pairings, while about one in six males in the lab experiments showed the same tendency despite exposure to females. "This behavior can be considered homosexual," he said.

Sexual Selection

But why should any males choose to mate with each other instead of with females? Such behavior apparently goes against theories of sexual selection, which predicts the optimization of reproductive success. Homosexual damselflies, however, aren't going to sire too many babies.

Homosexuality has been recorded in a wide range of animals, including beetles, sheep, fruit bats, dolphins, and monkeys. In many such cases explanations have been put forward to explain this behavior.

Consider, for example, the beetle known as the sugarcane rootstalk borer weevil. U.S. and Israeli researchers suggest the reason why females of the species mount other females is that the behavior attracts big males with good genes. Puny males seem to shy away from such antics.

Female Japanese macaques also engage in intimate sexual acts with one another. U.S. primatologist Amy Parish and other researchers say female macaques may enhance their social position and form alliance partners through such intimacy which in turn can boost breeding success.

Van Gossum and his colleagues propose a new explanation for homosexuality in animals like the blue-tailed damselfly. When males face strong evolutionary pressures to be flexible about their idea of what a female should look like, males may end up also fancying their own sex.

Males damselflies need to be adaptable because their female counterparts are adaptable. Numbers of the three main female color forms, or morphs, fluctuate over time.

Van Gossum, the study author, says most researchers agree such polymorphism most likely results from sexual conflict, with females evolving traits to avoid excessive harassment. While plenty of sex might suit male damselflies, this isn't the case for females.

Joan Roughgarden is a professor of biological sciences at Stanford University in California. She writes, "Copulation ranges from over one hour to over six hours, averaging three hours. While a long copulation might seem like great fun, this can waste a whole day and be too much of a good thing, especially if carried out day after day over a life span that is only a few days long."

Roughgarden adds that female damselflies collect all the sperm they need to reproduce from a single mating.

Aviodance Tactics

"Males go for quantity and females for quality," Van Gossum said. "As a consequence, females may wish to avoid excessive male attention. One way of doing so is by looking different from what a male thinks a female to be."

The blue female form may accomplish this by mimicking the appearance of males. But Van Gossum says an alternative theory is that male harassment also leads to other morphs.

"The minority female morph in a population"—whether blue or another form—"is the one that benefits, by receiving less male harassment," he added.

In turn, it's likely that males have developed a flexible "search-image" that matches the majority female fashion of the day. This boosts a male's chances of finding a mate.

"Males with a search-image that can be changed if the minority female morph becomes the majority morph are probably out-competing males that are less flexible," Van Gossum said.

Such flexibility may also lead to genuinely homosexual damselflies.

Van Gossum says such behavior could arise when a male is still young. A preference developed in male damselflies before reaching maturity, he says, is probably less prone to change in later life.

The Belgian researcher adds that evolutionary pressures that shape damselfly mating behavior may also explain homosexuality seen in other male animals, including butterflies and hummingbirds, whose females similarly adopt a range of colorful guises.
http://news.nationalgeographic.com/news/pf/48026386.html

This excerpt is also too good not to copy and paste:

"Damselflies, like all odonates, have a very interesting breeding system. Before they actually copulate, males and females of many groups spend some considerable time in physical contact with one another, presumably in an effort to assess their potential mate. . . . This physical contact is made by the male clasping the female's thorax with the four terminal appendages on the end of his abdomen. [Note in our photograph above each male holding its potential mate with its terminal appendage (and in the one somewhat more interesting case, the male holding the other male's abdomen.]

"The male's terminal abdominal appendages consist of two superior cerci and two inferior paraprocts. The [left] figure [below] is a computer generated model of the tenth abdominal segment of a male E. ebrium viewed from the posterior. These four appendages grasp the female's thorax while they are in tandem. The [right] figure is a computer generated model of the females thorax viewed from above. The male's paraprocts contact her prothorax and the male's cerci fit into the two plates on the anterior surface of her mesothorax - the mesothoracic plates. These mesothoracic plates are thought to be used by the female to assess the species identity and potentially the suitability of the male that is grasping her in tandem.

"Field studies have shown that females discriminate among males based on cerci shape (Paulson 1974, Robertson and Paterson 1982, Fincke et al. 2006). Also, males with experimentally altered cerci are rejected by conspecific females (Robertson and Paterson 1982). Thus, the morphologies of these male and female structures seem to be critical for mate recognition, and so the evolution of these structures may play a vital role in speciation in Enallagma. These structures are akin to a lock-and-key mechanism, with each sex potenitially evaluating the fit between the male's cerci with the contours of the female's mesothoracic plates."

http://www.enallagma.com/cerci/damselflyMating.html

Immature damselflies (known as naiads), live in the stream for a year or so until one emerges into the world of air and becomes the light-weight flying thing that resembles a dragonfly. The adult version will live for a few weeks to a few months, during which time its only real purpose is to mate. The articles above tell the first part of this story. The other part begins with the male arching his long abdomen over to his own abdomen where he will deposit sperm on the underside of about the second segment. (Some sources say that the male deposits his sperm onto this accessory sex organ before searching for a female.) He then clasps onto the female behind her head and she arches her abdomen under and around to retrieve the sperm. She, then, will lay her fertilized eggs on the surface of waters, bits of plant emerging from the water, in the mud, drilled into plant stems, or let go in the warm summer or autumn air itself .

Here's a drawing of part of the Act:

From the Pond, past the 3 1/2 pairs of damselflies, across the Stonefield,
and to the old Ruth Berry pressure pump.

And then up Whitman's Rough.

I focused mainly on the cedar elms along the east slope of Whitman's Rough above the home site. Buckeyes, junipers, persimmons, and other trees are dying, too. While I was sitting in a thin patch of shade beside the hose, a three-inch long lizard appeared on a water-spattered boulder. He went from one wet spot to the next, "lapping" up moisture as if in a frenzy. I don't know where he and other animals could possibly be getting enough water to survive.

With no creek flowing into it, the Pool warms and evaporates,
shrinking the universe for dozens of fish, tens of thousands of insects,
and gazillions of smaller invertebrates.

Always Beautiful

Last Sunday morning, a few of us met at the Creek to haul off scrap metal, drink cold tea, or walk slowly along the remains of the stream.

A kind couple had approached me while I was working the ambulance a few days ago, and they asked if I had any work for them, cutting weeds, hauling off junk, etc. I told them to meet me at the Creek Sunday. So for half a day in the sweltering loveliness of a little canyon, the two of them loaded their pickup full of old metal filing cabinets, electric wire, broken grills, and defunct yard-art. I hope they were able to exchange it for a worthwhile sum.

Some of Harlin's photos from that Sunday morning. :

Sesbania herbacea

Switchgrass

Widow Skimmer (Libellula luctuosa)

[The male Widow Skimmer differs from the female in that he shows the broad white patches mid-wing, as seen here above. Dragon flies have been placed with the taxonomic order Odanata, a group of insects that lived during the Carboniferous period, a time when the rocks of this Creek property were forming and some 100 million years earlier than the dinosaurs.]

Some faces.

"Third Rail"

And more from the drought. The cedar elms of the county seem to be taking it the hardest. These from up on Whitman's Rough next to the road.

Hillside Starvation

Snow-on-the-mountain (Euphorbia marginata)

These luscious plants don't appear to have been affected by the drought except positively and in an ironic sense: they managed to have lived next to some helpless blackberry plants that require every-third-day watering by the sad gardener. If it weren't for the drought, there'd be little chance such a beautiful plant would be so tall and stout.

Imagine a continuous train of water molecules extending from the tips of root hairs all the way up a tree's internal system of hollow columns through the trunk, limbs, and twigs to the undersides of leaves where one after another molecule of water is allowed to evaporate from tiny openings called stomata. Interrupt this train at the leaf, and the whole train all the way down to the root hairs stops.
When a tree battles for life during a drought, the odds of winning are greatly decreased if temperatures are high. So in these hot and dry times, the trees attempt to reduce the rate of water evaporation through transpiration by closing the pores in their leaves. But when they do this, they cannot bring in necessary carbon dioxide and end up dying a death of carbon starvation. It's the carbon dioxide that provides one of the necessary ingredients to photosynthesis.
One recent report showed that drought-stricken trees (pinon pine trees, specifically in this study) died at a rate 28% faster if they were also subjected to temperatures 7 degrees higher than normal. Depending on the source, July in the Austin area averages a temperature of 84.3, but this July the average was about 5 degrees higher at 89.7 degrees. Beating the average by 5 degrees over the span of a month is a big deal. We set a heat record for the month of July. Combine that with the driest twelve-month period on record, and the stage is set for brown-out here on Whitman's Rough.
The leaves wilt because of loss of turgor pressure in the leaf's blade and petiole, but they lose water from more than just the stomata pores on the underside of the leaves. It's probably safe to say that many of the trees up on the hillside have long since initiated stomatal control, so now they are losing water directly through the leaf surface, the twigs' lenticels, the stems, and the roots. Now we are to the point with some of the trees that if we were to receive rains from off a passing hurricane, many of the leaves' stomata will never open again, meaning that food production within the plant will be delayed or denied permanently. All the parts of the plant that contribute to its photosynthetic ability (chloroplasts, for example) may themselves be damaged and then take too long to recover before the tree dies of starvation.
Tiny roots just beneath the ground surface die and then the plant couldn't suck up moisture if you poured barrels of water on it. As a thriving plant draws up moisture, it carries nutrients along with the water. So shutting off the water supply also shuts off the nutrient supply.
Some trees shed their leaves in a last ditch effort to save the plant and will grow new, if somewhat stunted, leaves when the drought ends. Others lose the leaves and die. But even if they live, next year's growth will be retarded by this year's drought. Cambial growth slows when water supplies run low, and it's this year's cambial growth that helps set the limits of next year's growth potential.

Temperature sensitivity of drought-induced tree mortality portends increased regional die-off under global-change-type drought

Abstract

Large-scale biogeographical shifts in vegetation are predicted in response to the altered precipitation and temperature regimes associated with global climate change. Vegetation shifts have profound ecological impacts and are an important climate-ecosystem feedback through their alteration of carbon, water, and energy exchanges of the land surface. Of particular concern is the potential for warmer temperatures to compound the effects of increasingly severe droughts by triggering widespread vegetation shifts via woody plant mortality. The sensitivity of tree mortality to temperature is dependent on which of 2 non-mutually-exclusive mechanisms predominates—temperature-sensitive carbon starvation in response to a period of protracted water stress or temperature-insensitive sudden hydraulic failure under extreme water stress (cavitation). Here we show that experimentally induced warmer temperatures (≈4 °C) shortened the time to drought-induced mortality in Pinus edulis (piñon shortened pine) trees by nearly a third, with temperature-dependent differences in cumulative respiration costs implicating carbon starvation as the primary mechanism of mortality. Extrapolating this temperature effect to the historic frequency of water deficit in the southwestern United States predicts a 5-fold increase in the frequency of regional-scale tree die-off events for this species due to temperature alone. Projected increases in drought frequency due to changes in precipitation and increases in stress from biotic agents (e.g., bark beetles) would further exacerbate mortality. Our results demonstrate the mechanism by which warmer temperatures have exacerbated recent regional die-off events and background mortality rates. Because of pervasive projected increases in temperature, our results portend widespread increases in the extent and frequency of vegetation die-off.

Fresh green cuttings of Celtis laevigata and Smilax about to be taken to
Mr. Lyda's starving sheep up the county road from the Creek

Filling up with water to haul up Whitman's Rough
in an effort to save a few cedar elms

Mr. Rollins' Hog Shed at this stage of the renovation

February 13, 2011

A Nice Find

We appear to be living within what Texas climatologist John Nielsen-Gammon calls the state's third-worst drought since 1895. Somebody the other day in the feed store told me we were in "the middle of the worst Texas drought ever." One wonders about the use of the word "middle" when the remainder of the script has yet to be written. Whatever we call it, The Creek is about gone, the submersible pump lying in warm pond-mud is half an inch away from being exposed, and seven blackberry plants are dead with others on the way. We continue to water those that remain along with the fruit trees. Something will have to break soon.

Last night I had a dream: I was walking up the two-track road leading into the property to the Hog Shop we are remodeling now. I saw a small mountain lion walking in front of the building and wondered how small it looked. So I slowly approached it. But as I was almost upon the animal, I saw the real cougar: the small cat's mother was sleeping in the shadows next to my camera. So I continued to sneak up on it, reasoning that if a blog on a creek exists, and if a camera is to be had, then a photo of a mother mountain lion needs capturing. But as I reached out for the camera, the lion turned its head and . . . . I sat up in bed.

A few days ago, Harlin sent the following letters:

The point of a puzzle is the challenge. Thus, one does not go asking others for help since that pretty well obviates the reason for doing the puzzle in the first place. However, if it seems that the puzzle is partly solved and some new plant has been discovered for the first time in, oh, let’s say Burnet County, then one seeks expert help to verify the wonderful discovery. So, when I looked at the flowers in the first photo below, I saw two carpels joined by their stigmas and I supposed that the family would be Apocynaceae. However, there was nothing in that family that looked or sounded like the plant in the second and third photos below, so I sent pictures to one of the people at the UT Herbarium whose photos I often look at to help get on the right path. He wrote back that I had the wrong family. The plant was Mitreola petiolata in the Loganiaceae family.

Well, surely the key makers in the books had steered me the wrong way.

From this beginning I was led to the following new knowledge (supposing I have it right now). As you know, the “pistil” is the organ where the seeds are formed (ovary, style, stigma). A carpel is a kind of fundamental unit of the pistil. As I understand the story, long ago seeds were formed on the edge of a leaf and over millions of years these leaves evolved into carpels. A pistil may have one or several of them. A way to figure out how many is to count the stigma lobes, the styles, and the locules (the chambers where the seeds are), and the highest number is the number of carpels.

There is one more fact to get to the punch line. Dry fruit that splits open my have one carpel or more than one carpel. If there is just one (and the dry fruit splits down one side only), then it is a “follicle”. If there are more than one carpel in the dry fruit, then it is a “capsule”. Texas varieties of Apocynaceae have separate “follicles” united by their stigmas and Loganiaceae have separate “capsules” united by their stigmas.

Gaaa! Of course! What a fool I’ve been all this time. Follicles and capsules,…, I should have known.

Lax hornpod is then one of the professionally identified plants in the list of Hamilton Creek plants. After a few photos, the story continues with a second professionally identified plant. HH

Lax Hornpod (Mitreola petiolata)

Genus: Mitreola (my-tree-OH-la) comes from "mitra," meaning cap, headdress, or turban. Another name for this plant is Mitrewort.
Species: petiolata (pet-ee-oh-LAH-tuh)

And if we consult plant lists from China, we might find this same species: 度量草 du liang cao.

Here's a short little description of our plant in the event you might think one grows back of your kitchen door:

Annuals 10--50 cm tall, glabrous except for sparsely appressed pubescence or puberulence on young leaves, inside of corolla lobes at base, and fruit. Stems erect, simple or branched at base; branches 4-angled to narrowly 4-winged; internodes 1.5--6 cm. Interpetiolar stipules ± triangular, 1--2 mm. Petiole 3--10 mm; leaf blade ovate to narrowly ovate, 4--7 X 1.5--3 cm, membranous to papery, base cuneate, apex acuminate to obtuse, lateral veins 5--7 pairs and inconspicuous. Inflorescences terminal or axillary, 6--10 cm, many-flowered; peduncle to 7 cm; bracts and bracteoles narrowly elliptic, 1--2 mm. Pedicel very short. Calyx lobes ovate to triangular, ca. 1 X 0.5 mm. Corolla white, ca. 3 mm, tube ± as long as lobes; lobes narrowly ovate, apex obtuse. Stamens inserted at or near base of corolla tube; anthers broadly ovate, apex at ± middle of corolla tube. Ovary ovoid to subglobose, smooth. Style shorter than ovary, free to base; stigma capitate. Capsules ca. 3 mm in diam., pincerlike due to incurved apical horns. Seeds ellipsoid, ca. 0.5 mm, concave on one side, smooth. Fl. May-Oct.

Sunny areas on limestone, open woodlands, forest edges, edge of trails, grassy plains, valleys.

http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=210001297

Harlin continued:

After pointing out my error with the hornpod, the expert asked if there is any Chaptalia growing out there? It turned out that Chaptalia is on the Hamilton Creek plant list, and so I looked and found the dried remains, and then sent him a scan. It happens that the expert, Bob Harms, has just finished a study of this genus and could tell me that the name of the one at The Creek is Chaptalia texana. It also happens that there is not a record of this plant in Burnet County in the UT Herbarium. I offered ours, figuring they would do a better job of keeping it safe than I. He said it would help them, and so I figure it will end up as an official record of Texas plants.

You might want to tread carefully on the west side of the Hackberry tree that shades your car in the afternoon. The one by the drive close to the former garage. That’s where I found it.

We can mark this identification down as one that is as good as it gets. The person who just wrote the journal article on the thing being the one who verifies its name.

So, in a roundabout way I did find a plant that was new to Burnet County. HH

Silverpuff (Chaptalia texana)

[Harlin sent the following letter a few days later.]

It’s a bummer to ask and not receive. For every new kind of natural thing, I’m always asking what is it? I seem to get enough answers to keep going, but I have to admit many aren’t very satisfying.

For my nature questions, good answers come in the form of consistency. First, the search through the keys and the eventual words and pictures aren’t supposed to show any discrepancies. At that point, I feel that I may have the answer. However, that is not very satisfying, and it is much better if there is some feature that both matches and seems out of the ordinary. Weirdness increases the odds of being in the right place.

That brings me to Fuirena simplex. When I look at the photograph of the inflorescence (2264-sedge.jpg) or the scan (Sedge-300-231.jpg), I see a garden variety sedge and nothing that jumps out at me as being distinctive. But if I look at the top left drawing from the Flora of NA “Fuirena-simplex.jpg” and the photograph “2339-Fuirena-simplex-perianth-scale.jpg”, I see something that seems downright strange. There is this translucent thing on a stalk with a crystalline rasp at the end. Since there are drawings of a number of Fuirena species in the book, along with detailed drawings of hundreds of other sedges, I end up thinking I must have gotten pretty close on this one as far as the name goes.

Another positive aspect of weirdness is that weirdness is the way of memorable experience. Even if I did err as I went through the guidebook, I ended up seeing sights never before seen. As they say , it’s the journey and not the destination. HH

Western umbrella-sedge (Fuirena simplex)

Fuirena simplex

And here's part of how the Flora of North America goes about describing Fuirena simplex:

Herbs perennial, 2–10 m; rhizomes scaly, without cormlike buds, stout and short to long and slender. Culms tufted or in line on rhizome. Leaves: principal blades 5–20 cm, margins hispid-ciliate. Spikelets ovoid, lance-ovoid, or lance-cylindric, 8–15(–20) mm; fertile scales 2.5–3.5 mm. Flowers: anthers 3, 0.9–1.2 mm. 2n = 30.

Fruiting summer–fall. Sands, clays, peats, gravels, often over limestones, in interdunal swales, seeps, low open woods, savannas and prairies, often along stream terraces; 0–500 m; Ark., Kans., N.Mex., Okla., Tex; Mexico; West Indies (Cuba, Dominican Republic, Haiti, Jamaica, Puerto Rico); Central America; n South America.
http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242357841

Now for some lines by the poet Nikolaus Lenau, from his work entitled "Sedge Songs."

I

In the west the sun departing
Leaves the weary day asleep,
And the willows trail their streamers
In these waters still and deep.

Flow, my bitter tears, flow ever;
All I love I leave behind;
Sadly whisper here the willows,
And the reed shakes in the wind.

Into my deep lonely sufferings
Tenderly you shine afar,
As athwart these reeds and rushes
Trembles soft yon evening star.

II

Oft at eve I love to saunter
Where the sedge sighs drearily,
By entangled hidden footpaths,
Love! and then I think of thee.

When the woods gloom dark and darker,
Sedges in the night-wind moan,
Then a faint mysterious wailing
Bids me weep, still weep alone.

And methinks I hear it wafted,
Thy sweet voice, remote yet clear,
Till thy song, descending slowly,
Sinks into the silent mere.

III

Angry sunset sky,
Thunder-clouds o'erhead,
Every breeze doth fly,
Sultry air and dead.

From the lurid storm
Pallid lightnings break,
Their swift transient form
Flashes through the lake.

And I seem to see
Thyself, wondrous nigh--
Streaming wild and free
Thy long tresses fly.

And some lines below from "Sedge," by the German poeet Marcel Beyer:

Schilf steht auch über Land, steht
in der Schwebe, still. Schilf steht,
ich höre nichts, im Licht, du siehst
noch Schachtelhalm und Flechtwerk
linker Hand, und Tracht. Die Fragen
klingen nach im Schilf, die Wolken
oben, das Gesicht, das Atmen wird
noch in die Rede eingewoben. Doch
wie es um das Schilf steht, wie um
das Gewebe, ungewiß. Der Staub,
der Qualm, das Schilf neigt sich,
du sprichst, reicht weit bis in den
brennenden April, ich sehe nichts.

Sedge stands over the land, stands
suspended, quite still. Sedge stands,
I hear nothing, in the light, you still
see pewter-grass and wattle
to your left, and weight. Questions
echo in the sedge, the clouds above,
the face, even the breathing is
implicated in the talk. But the state
of the sedge, as of the implication,
remains uncertain. The dust,
the smell, the sedge, bows down,
you speak, it stretches far into
burning April, I see nothing.

"He Hears The Cry of the Sedge," by W.B. Yeats:

I Wander by the edge
Of this desolate lake
Where wind cries in the sedge
Until the axle break
That keeps the stars in their round
And hands hurl in the deep
The banners of East and West
And the girdle of light is unbound,
Your breast will not lie by the breast
Of your beloved in sleep.