Tuesday, December 29, 2009


-"Think like a mountain" Aldo Leopold

"Blue mountains endlessly walking" -- Tao

2009 marks the 100th anniversary of Aldo Leopold's tenure in the southwest, a stay that resulted in the invention of Wilderness, the formulation of a Land Ethic to treat that land as a value in itself and the realization, in "the dying green fire eyes of a wolf" that nonhuman nature might have purpose beyond us. This past year I, too, have been privileged to walk the southwest on the government's dime, but the dying green light I saw was not that of a wolf but of our biosphere. I look down from the mountains and into the future and see shadows, flames, and an end to innocence.

When Leopold encountered the Southwest, he was struck by the contrast of unspoiled wilderness and massive ecological degradation caused by cattle grazing and drought in the 1880's. His ecological awakening engendered a search for the causes of the anthropogenic changes he observed in the beautiful and fragile Southwestern ecosystems. Today, I am confronted by a second wave of anthropogenic changes. Instead of sifting the dust after the event, I am one of the cattle, raising dust, drying rivers. My first reaction was to try to stop or reverse these changes, and I spent two years pulling on that lever, knee deep in mud, with all my strength, determination, stamina and desperation. That era is over now, and this year, with help from my new girlfriend, Alexandra, I have moved past denial and anger to accept the changes that are taking place. My job now is to watch those changes, with the SW on the vanguard, and tell the story of this place, the weather-vane of the world.

My favorite places to hang a hammock are burned in stand-replacement forest fires, the pinyon nuts are harder to come by amongst the blight, and.. While it may be tempting to read the end of the world in these portents, the fact is that the world will go on, weirder and wilder than before. To those who would resist, or rest comfortably, or postpone, I say: Change is Coming. Change is the only constant. What we take to be ordinary is, in fact, extraordinary. But I also came to accept, through my studies of paleoecology and climatology, that no normal ever existed.

I met farmers who are outpacing the state to privatize water, who are resisting privatizing water, who have ranched and lived a way of life for 100 years and whose families probably will for another 100. Ranchers who are distrustful of the government and environmental groups, who love environmental groups but build their houses on the river's active floodplain, who watch tv to fall asleep, who realize the impact of their shopping at walmart to global justice and poverty, and who are, perhaps, more ineluctably tied to thieir cultural practices and our shared economy than they are to the land.

I've looked down on the glowing jewel cities sitting tethered and throbbing from tall mountains and thought about their future and my own. As a human it can be difficult to think of humans as a force of nature like the wind and the sun, but as a scientist the evidence is clear. More people live in large cities and interconnected suburbia than on farms and ranches, and more people are alive today than ever before. Where people live in high concentrations they have completely transformed ecosystems from grasslands or forests into asphalt, houses, and watered trees. To survive from one meal to the next, to make the water run from the faucet, heat, light, all require vast subsidies from the country, which is systematically transformed (though still not to the same degree as the city) to pump services from afar into the city.

Therefore, we create environments that are constantly disturbed, and increasingly homogeneous. Another term for the anthropocene would be the homogocene, when everything is mixed up so much that place ceases to matter. The same species will be found everywhere, the same structures of concrete, metal, plastic, glass, symbols, Virtual.

Disturbance will continue to reset the clock on ecosystems, making oldgrowth ecosystems increasingly rare. Instead, we will become even more accustomed to bland, early-successional weedy eocsystems adapted to high (human) disturbance. I have walked the gradient from unimpacted ecosystems to totally impacted human ecosystems, and the changes are systematic and predictable. Usually, the ecosystem becomes more weedy or barren, and eventually entirely nonfunctional. However, even at the extreme cities can support some species of wildlife, and perform some ecosystem functions, depending on how they are built. Cities are not inherently cancerous on the surface of the earth, although they are metastatizing.

The ecological role of humans, tho, is not as organizers of energy, or even to change functioning ecosystems to nonfunctional ones, but, rather, as "seed dispersers and agents of disturbance (change)". Thus the ecologist diagnoses the humans.

Thursday, December 24, 2009

Americans throw away more food than most people consume

According to a paper by Kevin Hall et al in PLoS, Americans waste about 1,400 Calories a day, about as much as is needed to feed an average adult in much of the world. They arrived at this figure by calculating the total number of food calories produced on farmland in America (plus imports, minus exports) and compared this to the total calories consumed by Americans. Although we Americans are doing our best to consume large amounts of food, we still end up throwing away or otherwise wasting enough food every day to feed another person.

Saturday, December 12, 2009

Dying Forests

“For as long as people have been looking at such things, we have never had the series of attacks on forest health all occurring at the same time that we are currently experiencing,” said Alex Woods, a forest pathologist in British Columbia. San Diego News Story: Drought, Beetles Killing Forests 10/25/08

Even this wide-reaching chart apparently doesn't have room to show SAD (Sudden Aspen Death) nor the Southwestern Pinyon Pine Die-Off. The title of the paper in PNAS (2005) by Dr. Breshears et al sums it up: "Regional vegetation die-off in response to global-change-type drought."

In Colorado, spruce beetles have killed entire forests around North Park. Throughout the central Rockies, approximately 2.5 million acres have been or are being destroyed.

White Pine is also dying throughout the West, and although those maps are still being drawn, the outlook isn't good: "We're watching the collapse of an ecosystem in less than a decade. " A view of part of the forest mapped above:

From New Mexico Work
Some possible causes. One proposed solution.

Wednesday, December 09, 2009

Anthropogenic Climate Change

click map for animation
I don't usually like to state opinions without understanding the facts. So, for climate change science, I've long counted myself a skeptic; yes, even after Al Gore's Inconvenient Truth. Because a great deal of my professional work revolves around ecology and ecosystem science, I have kept up to date on the science of climate change, and recently have begun looking deeper. I found a number of sincere climate change skeptics. I read their arguments, and then searched for and found rebuttals in science papers, books, and websites. While my research will continue to be ongoing, I am forced to conclude that the evidence for human-caused climate change is compelling. Action to stop business-as-usual fossil fuel use is urgently necessary.

Interestingly, I've also concluded that climate change skeptics are actually a boon to climate scientists. Their consistent questioning helps bring attention, interest, and even intrigue to discourse that might otherwise tend toward dry fact. And their analyses provide ready-made hypotheses to test for young graduate students. However, after considering their claims and scientist's responses, I can not doubt that the best available science indicates humans are modifying a continually changing climate at unprecedented rates. The climate is warming, and more and more of that change is attributable to humans.

However persuasive the evidence may be, it can also be overwhelmingly complex; the important point to remember is that we are having a significant effect on the environment. But you don't need 10,000+ dedicated and careful scientists to tell you that. Climate change skeptics start from a disbelief that humans could modify something as large as the entire Earth ecosystem. But look around you. Odds are, your entire environment is human-made. And it doesn't stop there. From airplane flights or Google maps we see human civilization spilling out over vast swathes of the landscape. Even in areas that are not paved over, the trained ecologist sees omnipresent invasive species, erosion, and pollution. In many parts of the world, natural areas have been completely transformed by human activity.

My favorite climate change objection raises the possibility of bias in temperature readings taken from areas that have recently urbanized. This "urban heat island" effect is a known source of bias and is corrected for in long-term temperature trends. However, it is becoming more difficult to find locations unaffected by urban heat islands effects as urban areas increase in size and coalesce into megacities. This, at least, is incontrovertible fact: we are seeing a complete transformation of the surface of the earth. Indeed, 2008 was the first year that more people lived in cities than in rural areas.

The good news is that although our impact on the environment is significant, and growing, it is largely based on cumulative effect: in any given year, we are not really that far from a sustainable society. Ending coal power and then using clean energy to power our transportation networks could do it. However, the first step is to stop building new coal power plants. If not for the critical build-up of heavy metals pollutants in the food chain, or the respiratory health of people who live near coal plants, or the massive ecological devastation of mountaintop removal and open-pit mines, than for the entire health and fate of the planet.
click image for fire animation
Of course, it will take far more to learn to live and coexist with the natural world and its constantly evolving cycles and processes (flood, fire). It would be a tragedy, however, if we listen to the science skeptics at the expense of the skeptical scientists, and continue on our present unnecessary experiment with global warming. Even if all of our theories are wrong, that should only motivate us more strongly to stop playing God with the Earth. We need to slow down and give nature time to adapt to our sickly civilization, or, better, we need to slow down and adapt our civilization to the healing Earth.

I have read the papers and considered the arguments and believe that we must act. Business-as-usual imposes an unacceptable risk of catastrophic consequences. There should always be time for doubt and discussion, but not while we and China continue to build coal power plants.

In-depth scientific information on climate change.

Sunday, December 06, 2009

Ecotourism in Mexico

Chamela-Cuixmala Biosphere Reserve, Jalisco,

Thick-billed parrot preserves on Ejido...(mentioned in Wildlands Connections)

Monday, November 16, 2009

La Jencia Restoration Project Evaluation after 10,000 CFS Summer Flood

"No characteristics of the channel provide indication of why some reaches scoured when the rest of the reach filled ... When there are a large number of interrelated factors which must adjust among themselves in response to occurrences in the environment, such as storms or flows, it should be expected that there will generally be an indeterminacy in the manner of this mutual adjustment.... Where a particular factor dominates, such as a bedrock floor of a channel, the effects of this factor may be readily evident. However, where the alternatives become more nearly equivalent it becomes more difficult to specify the precise form in any give case...This indeterminacy in a given case results from the fact that the physical conditions, being insufficient to specify uniquely the result of the interaction of the dependent variables, are controlled by a series of processes through which any slight adjustment to a change imposed from the environment feeds back into the system." (Leopold, Wolman, Fluvial Geomorphology. describing the equivocal results on their study of the dry wash (ephemeral channel) near Santa Fe, NM Arroyo de los Frijoles:)

From La Jencia Assessment Fall 2009

La Jencia Ranch is located near the continental divide, west of the Rio Grande, north of the Magdalena mtns at about 5500 feet in a broad almost-closed basin composed of Pleisticene-sediment. Springs feed an intermittent reach in what is otherwise an ephemeral system. The watershed above this point is approximately 350 square miles, and large bursts of storm water have contributed to massive erosion in this area. By anecdotal reports, this entire canyon system (with 100+ foot walls) has cut in the last 120 years since Anglos homesteaded in the 1880s. This report is corroborated by the evidence of recently rejuvenated side canyons and active headcuts.

A continuing riparian restoration project has been focused on planting trees throughout the developing floodplain and meander cutoffs near ranch HQ. The continued lateral and vertical (down-cutting) erosion in the canyon is a management concern.

In the storm of 2006 a number of major hydrogeomorphic changes took place, notably the cutoff of several large meanders. This had the effect of significantly shortening and steepening the main channel. In a ~10 foot flood this September, another large meander was cutoff, in addition to significant erosion (and deposition) in other parts of this very dynamic system.
From La Jencia Assessment Fall 2009

scoured out or deposited feet of sediment on benches cuts some places, stable others
looks like it wants to meander morehas active floodplain
flood was 6-10 feet high
widened in some places
in other places sedges and willows in middle survived
large meander cutoff downstream of house

General Conclusions:
did not downcut (degrade) during this flood, contra the 2006 flood. While an over-meander did cutoff as could be expected, it did not create a headcut, as was feared.

stream has access to floodplain. some deposition and scour over this surface is natural. La Jencia is a high-disturbance system.
NOT Down-cutting, and possibly AS GOOD AS IT GETS
From La Jencia Assessment Fall 2009

Caveats: It is important not to be drawn into individual cut banks, but rather to evaluate the system on a whole.; "the failure of some in stream willow plantings (ISWP) does not invalidate the concept". In fact, some of the outside-meander plantings did hold. Other reaches of the channel that don't bend as much and had thick sedge growth were almost unchanged. Eventually, the entire channel could look like these reference reaches. However, whether planting can drastically change what would already happen otherwise, is unknown. Perhaps more a function of how many years between scouring floods.

: inability to think in derivatives (rates)
"average" wide distributions of high frequency-low magnitude events with low frequency-high magnitude events
talk about average or equilibrium in the midst of constant flux (writhing serpent metaphor for channel evolution)
think about very complex systems (see climate change). things are changing, but is there a trend (what scale to think (average) at?) and are we affecting it?
compute running averages at different scales

Case Examples:

There's a difference between downcutting (lowering of base elevation) and degrading, which could include lateral erosion. Steepening is another thing altogether. So, for example, at the meander cut-off, the grade steepened and the channel length shortened, but a headcut did not start, and areas immediately upstream and downstream are still at the same elevation, so downcutting did not occur. Whether this area ends up aggrading at the bottom of the steepened section or degrading at the top of the section depends on the nature of future hydrographs and sediment supplies.

The uplands are key to understanding how "natural" the channel evolution and morphology are. Grazing stress has been removed on-site, but could still be contributing to watershed degradation. Measurements of runoff on grazed and ungrazed areas of the watershed could yield calculations about the magnitude and frequency distribution of floods. La Jencia, like other ephemeral streams, may not be wet enough to support enough veg to maintain stability in the face of giant floods. Or maybe floods are changing in magnitude.

If the channel is slightly unstable, as indicated by the variance of Van's channel cross sections, this continued instability could be attributed to the nature of the system (basically, ephemeral) and/or the condition of the contributing watershed (degraded, causes increased ephemerality and flashiness).

Van emphasized the sediment supply could be contributing to instability, and that this sediment was locally generated by the magnitude of these events. Was this a 20-year flood?
From La Jencia Assessment Fall 2009

"Apparently the tendency for the maintenance of quasi-equilibrium in stream channels is sufficiently pervasive that only slight deviations, if sustained for long enough periods of time, may account for aggradational features of considerable magnitude, but the deviation from equilibrium conditions necessary for the construction of such depositional features cannot be recognized or identified by any criteria now available. Only by measurement over time can the net direction of river change be determined..." (Leopold, ibid)

Flannery's Theory of Ecosystem Nutrient Cycling

Tim Flannery's exposition of fire- vs herbivore-dominated ecosystems:

"Large herbivores return nutrients to the soil quickly and with a bonus (nitrogen fertilizer). Fire returns nutrients to the soil only after a long period--and then at a considerable loss. As a result, fire and soils act to promote each other. Together, they can produce an ecosystem which is spiraling ever downwards as nutrients become fewer while fires become more important.

The result of this cycle is an accelerated selection for scleromorph plants, which can survive in nutrient-poor soils. A self-reinforcing cycle of soil impoverishment, soil drying and soil exposure is then initiated. Much water is lost through runoff in such situations before it can be returned to the skies through transpiration. This lowers effective rainfall. Degradation can go so far that even if fire can be stopped, the soil is so impoverished that it can no longer support the kinds of plants needed to feed large herbivores. Thus, the change can be made almost irreversible.

A canopy of broad-leaved 'dry' rainforest species, such as survives in tiny fire refuges across the north of Australia today, could, if they were more widespread, enhance rainfall by up to 60 percent and push rainfall much further south. This is because the plants and the soils they protect retard the runoff of water. Through the leaves in their dense canopy they release vast amounts of the trapped water as moisture into the atmosphere. During the wet season, the winds blow in from the coast. As a result, the moisture transpired by the plants is formed into clouds and blown southwards to fall again as rain.

Most of northern Australia is covered with eucalypt woodlands today. After rain, the water rains rapidly away, for the plants and thin soil cannot hold it. The release of moisture to the atmosphere through the narrow eucalypt leaves is insufficient to form significant clouds. As a consequence, the rainfall gradient between the coast and inland is incredibly steep in northern Australia."

The diagram at the beginning shows three types of soil: Mor, Moder, and Mull, which range from slow/intermittent decomposition (Mor-fire) to fast/continuous decomposition (Mull-earthworms).

Tamarix ramosissima survey on White Sands National Monument

White Sands National Monument is located in the Tularosa Basin and surrounded by White Sands Missile Range, the site of the first atomic bomb test. The area is desolate and remote and still used for target practice. The dunes are composed of gypsum, a salt that accumulates in the dry lakes and playas of this closed basin.

From White Sands National Monument

Our Mission: Vegetation mapping plus Search & Destroy Tamarix ramosissima AKA Russian Salt Cedar. Our goal was to ground-truth vegetation maps and locate populations of this invasive species for possible future air strikes.
From White Sands National Monument

Cottonwoods grow in the dunes because of the shallow water table.
From White Sands National Monument

We traveled by sand buggy.

From White Sands National Monument

From White Sands National Monument
Many dunes are stabalized by Rhus Trilobata (Skunkbush Sumac), Poliomentha (Rosemary Mint Bush), Chrysothamnus (Rabbitbrush, Chamisa), and Yucca.

From White Sands National Monument
Tamarix ramosissima visible in the background. The foreground is covered by a thick salt crust.

Friday, November 06, 2009

Rapid Climate and Vegetation Change in Arizona

Recent modeling (deMenocal et al 2000 Quaternary Science Reviews) of the Sahara's transition from a Serengeti-like grassland to sand dunes indicates that the transition, while forced by overall climate change, happened suddenly, probably as a result of positive feedback from vegetation changes:

As vegetation declined, a critical point occurred around 5500 years ago and the Sahara was born, in possibly only 100-200 years. The top chart shows overall climate change, the two middle charts show models without, and with, vegetation feedback, and the bottom chart shows the paleoecologic record, where "Terrigenuous Flux" is a measure of erosion and sand dune formation.

An analogous rapid vegetation change has been observed in the American Southwest, prompting some to ask if Arizona and New Mexico could be the next Sahara...
(image composite from Santa Rita Experimental Range, University of Arizona)
As landcover transitions from grasslands to sparse shrublands, erosion can increase (Breshears et al 2003 Earth Surface Processes and Landforms). Vegetation cover can also influence rainfall (Kurc et al 2003 Water Resources Research), initiating a positive feedback.

The long-range outlook for the American Southwest is not good: “Model Projections of an Imminent Transition to a More Arid Climate in Southwestern North America” — yes, “imminent” — and reports “a broad consensus among climate models” that a permanent drought, bringing Dust Bowl-type conditions, “will become the new climatology of the American Southwest within a time frame of years to decades.” (Seager et al 2007 Science)
Four representative climate models showing Precipitation minus Evapotranspiration over the entire Southwest. The second model, GFDL, is arguably the worst scenario. However, because the Southwest is so dependent on the Summer monsoon, whose dynamics are not well understood, these models should be taken with a grain of salt. Interestingly, El Nino events in the Southern Pacific, which are marked by increased sea-surface temperatures, often increase the ammount of rainfall in the Southwest, especially during the Winter. Indeed, we have been experiencing a strong El Nino since April which has resulted in a nice wet summer, and hopefully will continue with a wet winter as well. Stong El Nino's also correlate with decreased precipitation in the Northwest, which explains why Washington had a very dry summer this year. It is interesting to note that this relationship has changed over time.

However, the vegetative response to El Nino isn't always simple, either. While summer rains definately benefit native C4 grasses, winter rains tend to benefit invasive C3 shrubs. So, even if the total ammount of precipitation doesn't change, a changed timing or frequency/intensity could continue to drive massive vegetative change, which could in turn continue to influence the climate.

USGS concludes 2006 was 1,000-year flood near Tucson

Floods are described in terms of their recurrence interval. A 10-year flood has a 1 in 10 chance of occuring each year. Many engineers and flood planners work with 100-year floods, since this is approximately the length of accurate and reliable observations in the West. However, much larger events can, and do, occur.

After studying the aftermath of the floods that wiped out Sabino Canyon in Tucson in 2006, the USGS has concluded that the event was virtually unprecedented. By dating geological deposits, they estimated that the floods that swept down most of the West-facing canyons in the Santa Catalina Mountains were probably on the order of a 1,000 year flood.

However, with climate change and associated land cover changes on the mountains, that interval may no longer hold. Pearthree, section chief of AZGS Environmental Geology, warns, “increasing fire frequency on the steep slopes of the Santa Catalina Mountains due to invasive species like bufflegrass may result in greater runoff, and possibly increased debris flow frequency, in the coming decades.”

Details, including an map.

Other recent flash floods.

Wednesday, November 04, 2009

Quivira Coalition Water Symposium

Quivira Coalition Annual Conference

Speakers I enjoyed:

Peter Warshall
A-->B Horizon (CF. History of Greece)
some grasses like B horizon (maybe Hairy Grama?)
1,000 years to restore
Vigil network data
Leopold was against "drop-in science"

Larry Schmidt
--> channel incision
lack of sediment incises below stream
-->too much water (culverts)
-->too much slope
-->wildfire causes no cover, hydrophobic soil, runoff w/out sediment
results in incised channel (sediment hungry)
positive feedback between reduced cover, dendritic incision, and loss of wateravailability

Burchard Heede Alkali Creek 40 years
showed that landscape incision could be corrected by creating a grass-lined waterway
induced meandering can also cure incision

Bill Zeedyk and Van Clothier
streams can erode bottom OR sides
*anticipate* stable form
*nudge* in that direction

e.g meander multiplier is usually between 10-20: 10 for wet sedge meadows, 18 for dry ephemeral channels
utility of BF-FP width ratio?
how does flow become channelized (versus dispersed)
why aren't incising channels self-correcting? are they?
structures needed b/c of lack of woody debris?

Monday, October 26, 2009

Mesquite Treatment Monitoring in Lesser Prarie Chicken Habitat

Mesquite has invaded large areas of warm semi-arid grassland, possibly due to a combination of land use and climate change. Fenceline contrasts usually indicate selective growth is due to land use; in the case below the field on the right is grazed while that on the left is a Conservation Reserve former farm field.
From Milnesand, NM
The mesquite has been sprayed with a selective herbicide in order to increase forage access for cows. Our goal was to monitor the vegetation changes associated with mesquite die-off. I also observed that mesquite and other shrubs clearly stabalize more eolian transport than do grasses.

Yvonne: "looks like pretty good kill to me. I don't know what he's complaining about. You never get 100% -- not in nature"
Rancher: "never seen it this green this time of year before"


lark buntings dance from mesquite to mesquite
trilling as they fly: pipsqeek joy
horsecrippler cactus
we dug and boxed for home

From Milnesand, NM
two Great Blue Herons flap-float overhead
bringing/bearing profound stillness
tarantulas still crossing road
honk/gurgle of sandhill cranes float out
of clear blue sky

From Milnesand, NM

Damn scorpions - one just crawled under fridge
pocket gopher diggings everywhere!
Panicum obtusum, virgatum
spider webs shimmer parachute? balloon?
Look! a tiny spider clutching the tiptop of a tiny Buchloe grass
it flies away, and for a moment; Pure Magic

From Milnesand, NM
12:30 2 groups of 3 and 4 cranes, circling overhead
another group of 2 joins them
we hear them long after they are lost in sky
their presence gives it dimension, then dimensionless

From Milnesand, NM

Wednesday, October 14, 2009

Tucson Field Notes

italisize scientific names

snow and hills in Arizona winter:
warming sun, purple hands in the snow & shade

Madrean oak to pinon mixed conifers
how many species of oak? and species we don't even know
sample in pockets

pinus edulis
apache pine englemanii
mexican pinyon pinus cembroides

chihuaha pine? pinus leiophylla
doug fir
white pine pinus strobiformis

alligator juniper

steep steep slopes still with soil on them
in some places, thick oak duff
overlays silt and rocks over bigger rocks and boulders and bedrock
exposed in channels and on pinacles

raccoon faced white elipses
blue colored breast
darker blue on dorsum than back
same blue makes crest color protude through white head
arrow shapped fat end over eyes
(sagital crest on forefront of head )
eye circle bigger than eyes is white
raccoon faced?

insect casings exoskeletons left behind after metamorphisis
thalictrum and gallium near trickling pools
stinging nettle near Sylvester Spring
round sedges (scirpus), rorripa
exclosure around the seeping proliferation: out of the reach of
raging floods, stable ecosystems contrast with high-disturbance
sylvester had stinging nettle and white pine
(pinus strobiformis)
 kent spring, at the apex or azimuth, a frozen stalagmite
and  bog with the foot-thick grape vine
springs boxed and improved "fish and game"

white breasted nuthatch

pinus leiophylla chihuaha
arbutus arizonica (ericaceae... heather the grown up form of ) like arbutus
symphoricarpous oreophilus mountain or roundleaf rotundifolius

ericaceous shrubs in the artic tundra

rhus trilobata on west facing dry hillslopes
Hoffmansegia glandular pea vine there, to

littleleaf sumac
rhus microphylla fruits small, red-hairy, {ital}

bear grass nolina microcarpa
banana yucca, Yucca baccata

parry's and shott agave (mescal and amole)

red pink ball things
green horn beetle 2mm-4mm
horn downcurved

galls we saw today
lemons in the trees: hollow dry bug galls
perforated ball of Sycamore seeds
red tiny balls
caccoon with a hole
pinecone skeleton twigs twisted together to make backbone and ribs
intricate engineering
concave sycamore with hollows
juniper stumps convex, many-trunked
grassy hills under
aligator juniper blue "bloke" oak

grape vines common near springs
swaying 30-40 feet overhead
crawling over oaks
some are a thick as 8 inch 
complex webbing

abundance and habit

no cottonwood in wash
close, steep sides
bedrock confined
maiden pools? dried up

arizona rosewood  vauquelinia californica
southwestern coralbean erythrina flabelliformis growing around summit, blue "bloak" oak,
black phoebe
ventana canyon over stream

dodonaea viscosa called uopbush
hopbush covered burn sites and common at a certain elevation

romero pools
coursetia microphylla along rough rock trail
towering saguaro
past them to the first shady clefts
oak and fern,
then onward to flowing water over bedrock

dodea cover the site of a 2003 fire now with 10 foot luxuriant growth, hop bushes swaying in the golden light

Sunday, October 11, 2009

The Magical North Central Texas that Used To Be

North Central Texas is composed of three major ecosystems, the Cross Timbers, Black Prairie, and Fort Worth Prarie. Less than 150 years ago, sparkling streams were abundant with trout, perch, and catfish...and alligators! Indeed, Kendall (1845) found alligators along the San Gabriel in the southern Blackland Prairie as "too plentiful for any useful purposes." Black bear were also common, along with mountain lion. Brooke (1848) reports gray wolves as far east as McLennan County, ocelot in bottoms of Brazos River near Waco in McLennan County. The last jaguar record was a large male killed in Mills County (Lampasas Cut Plain) in 1903.

Other vanished creaturs out of this Noah's Ark world include river otter, ringtail (a cat-like creature), badger, javalina (collared peccary), bison, pronghorn antelope, turkeys, and prarie chickens. Many of these animals still persist in zoos or mountains out west, but some cannot be found anywhere on the planet. For example, both the ivorybilled woodpecker and the carolina parakeet, once found near modern day Dallas/Ft. Worth, are extinct.

Estimates of the destruction of the Blackland Prairie ecosystem range from 98% (Hatch et al 1990) to 99% (Riskind and Collins 1975) to more than 99.9% (Burleson 1993). Some of the last remnants can still be seen at the Nature Conservancy's Clymer Meadow Preserve. Slightly more Fort Worth Prarie and Cross Timbers survive. Dyksterhuis (1946) studied relics of the Fort Worth Prairie, and, surprisingly, Cross Timbers are still one of the largest relatively unaltered forest vegetation types in the eastern United States (Stahle &Hehr 1984), but there are more in Oklahoma, for example, Pontotoc Ridge Preserve. Examples of old-growth Cross Timbers forests in North Texas are found in Comanche County (Leon River), Tarrant County (Fort Worth Nature Center), and Throckmorton County (Nichols Ranch).

Prairie remnants are threatened by eastern red cedar (Juniperus virginiana) and cedar elm (Ulmus crassifolia) because of a lack of natural fire. Results include reduction in broad-leaved plants and increased abundance of grasses. (Diamond & Meins 1993). Over much of the slope-lands, as muich as three feet of soil have been eroded, exposing barren rock where once was prairie soil (Hayward &Yelderman 1991). So, although remnants remain, they are often degraded by various human activities such as heavy grazing or selective cutting and their authenticity is rarely noticed or protected.....I wonder how many people realize what used to be?

Much of this text, and the image, are from Shinner's and Mahler's Illustrated Flora of North Central Texas, published by Botanical Research Institute of Texas.

More great info about Texas Native Plants, from the Plant Resources Center at UT - Austin.

Saturday, September 26, 2009

Calibrating Bank Full Measurements Using Regional Curves and USGS Stream Guage Data

Bankfull is important to fluvial hydrogeomorphology (HGM) because it often determines the shape of the channel by moving and depositing sediment. Bankfull (BF) is defined as the high water level that recurs every 1 - 2 years, but measuring it in the field involves using multiple indicators in a 'preponderance of evidence' detective-style approach.

Most plants that cannot tolerate saturated soil conditions for days at a time, like Alders, will not grow below BF, while willows and cottonwood can. Also, the top of point or side bars can indicate the height of BF, but on the Rio Embudo, near Dixon NM, BF indicators were contradictory and hard to find. Is BF just a few centimeters above the base-flow water, or are all the willow below BF?
From Rio Embudo at Dixon, NM Hydrology Analysis
A number of bars and scour features at different heights further compounded the mystery. It was time to seek out other clues. One source of potential indicators was our aerial imagery, which was taken during Spring runoff, 2008:
From Rio Embudo at Dixon, NM Hydrology Analysis
The point bars at bottom right are bisected by a side channel that is several feet above the base level today. That means BF must be at least that high, and would probably inundate most of the willows. Corroborating this, the landowner reports that the willows are indeed flooded almost every year. But exactly how high is BF? To gather more data, we surveyed three channel cross sections, or transects (TR), noting the heights of the major terraces.

From Rio Embudo at Dixon, NM Hydrology Analysis

From Rio Embudo at Dixon, NM Hydrology Analysis

From Rio Embudo at Dixon, NM Hydrology Analysis

On each of these cross sections we marked where the current base flow water level is, where we think BF is, and where we think Flood Prone (FP) might be. To check these guesses, we correlated those heights with flow data from a USGS gauge just downstream:
From Rio Embudo at Dixon, NM Hydrology Analysis
From this graph we could see that the high water level with recurrence every 1 -2 years is about 400 cubic feet per second (CFS). We could also see that the current flow was about 38 CFS. If the Rio Embudo is flowing with 38 CFS today, how high would a BF flow of 400 CFS be?

between the flow today and BF flow. To figure that out we might need to correct for any changes in the velocity (feet/second). Manning's Equation:

shows that velocity V is proportional to a constant, u, inversely proportional to a coefficient of friction, n, varies to the 2/3 power of channel cross-sectional area, R, and to the 1/2 power of slope, S. Since neither slope nor the constant would change, we can discount them and focus on n and R; n will likely increase because the willows will act like a series of giant combs, increasing friction, and R will also obviously have to increase. For example, doubling the height of the water would multiply that term by 1.6. Unfortunately, coefficients of friction need to be experimentally determined, so we can only guess at n. To make things easier, I decided friction would also increase by a factor of 1.6, to exactly cancel out R. In other words, I don't think the velocity would change by much.

So it is a simple matter of geometry to calculate the cross-sectional area that would correspond to 400 CFS on our cross sections (red lines on the cross-sections, above). Without exception, this height is higher than our field-determined BF (green lines on the cross-sections, above) and, at least for TR-L, even higher than our FP height.

But is this right? Are we getting closer to the truth? To check, we can calibrate our answers for the Rio Embudo against data published by Natural Channel Design on a large number of other Southwestern rivers:
From Rio Embudo at Dixon, NM Hydrology Analysis
I plotted both our field-determined BF cross-sectional area (green points) and the USGS-determined BF cross-sectional area (red points) on the regional curve above. The green points seem to fall on the line for New Mexico, while the red points fall on the Arizona line, corroborating our field measurements and casting doubt on the USGS. However, the watershed above Dixon is very impermeable and could behave more like AZ than NM. I think the true value is probably somewhere in-between the field and USGS values.

This line is probably as close as any to Bankfull:
From Rio Embudo at Dixon, NM Hydrology Analysis

Evaluating Restoration Potential at Taos-area Streams

We use a four-tiered scale to rate restoration potential, basically A, B, C, D:

A is fine, possibly excepting some irrigation
B is for "needs beaver!", and/or stop grazing
C needs instream structures and earth moving equipment to restore functionality
D can't be helped

From Natural Heritage New Mexico - Taos Streams

Rio Costillo. Upstream landowner's home is within flood-prone area and would certainly be an impediment to any restoration effort, while downstream landowner's stretch has been dredged. D
From Natural Heritage New Mexico - Taos Streams

Rio Fernando: A thriving beaver population has created extensive wetlands composed of Typha and Salix exigua, but completely extirpated Populus from the reach. A (maybe plant cottonwood)
From Natural Heritage New Mexico - Taos Streams

Santa Barbara Upper: A main channel circumvents the beaver ponds and side channels and appears somewhat channelized, with low habitat diversity (and hence few fish). What is causing the main channel to bypass beaver dams and downcut? A?
From Natural Heritage New Mexico - Taos Streams

Rio Pueblo: Irrigation returns from irrigated pastures along the North; humans have attempted to replace breached beaver dams and drying beaver ponds with rock-and-plastic "fisherman's dams". B

For more site descriptions, click on the links above.

Wednesday, September 23, 2009

Rio Puerco, NM: BEFORE and AFTER

The furthest downstream restoration site is doing well. Note how the roads have revegetated.
From Rio Puerco Restoration Evaluation - September 2009

The large berm in the background is the "remeander" dam that was built a couple years ago to push the Puerco back into its original channel. In the foreground an In-Stream Willow Planting (ISWP) immediately after it was planted (left) and then after a single growing/flooding season (right). This planting did not incorporate wattles. It has largely washed out as the river channel continued its lateral migration toward river right. A large amount of new erosion is visible along the right side of the channel, which is exactly what this planting tried to prevent. Unfortunately, it is working against the natural migration of the river.
From Rio Puerco Restoration Evaluation - September 2009

The same ISWP, looking upstream. The main channel is now flowing (and cutting) right along the bank. The point bar on the left has widened.

From Rio Puerco Restoration Evaluation - September 2009

These photos show the Guardian's plantings immediately downstream from the bridge. This old channel is now receiving flow because of the remeander. It is a healthy channel with an active floodplain. All of the cottonwoods and willows received overbank flooding from the summer monsoons, and did very well. Its a real jungle down there!

From Rio Puerco Restoration Evaluation - September 2009

These photos show an ISWP on Guardian's State Land. It is the middle of three such ISWPs on State Land. The channel through this reach is downcut and straight, almost like a ditch, and the plantings sought to induce meanders. While the plantings didn't wash out, it doesn't look like the willow are doing very well; in this wet year the bottom of the channel may have been too wet for them. Looking further downstream, one can see sedges growing into the channel, forming a natural meander pattern. Planting sedge plugs may be more effective below bankfull.
From Rio Puerco Restoration Evaluation - September 2009

These photos show the downstream area of the Guardian's State land that was planted in 2008. The ISWP from 2008 is not quite visible under the large cut bank in the center distance. The development and change of the river's channel and associated point bars are visible in the foreground.
From Rio Puerco Restoration Evaluation - September 2009

For more information and more photos, click on one of the photo links above.