Oktoberfest 2014 in Portal Arizona

Time again for the annual event of Oktoberfest in Portal.  Held as a fund raising event for the Sew What Club in Portal, Oktoberfest is another chance for the community to gather, see old friends, exchange the latest gossip, and generally catch up on events in the valley and surrounding mountains.  All while enjoying a great lunch in the mountain air of Portal AZ and Cave Creek Canyon.

Oktoberfest getting started on a sunny Saturday morning.

Friends of Cave Creek Canyon at Oktoberfest

The German cafe with brats and sauerkraut.

The Final Sorting

Well over a hundred harvester ant colony mounds were explored and the data used to demonstrate that harvester ant colony densities were a function of grazing intensity on the landscape around the Painted Pony Resort.  Finally, all the small crystals collected from the mounds were sorted.  Quartz, in the form of Chalcedony as well as small quartz crystals (6 sided) were noted in the samples as well as other crystal morphologies, such as cubic and octahedral crystals.  The first image below was taken with a digital microscope and shows the variety of crystalline forms found around the harvester ant colonies.  The next 2 photomicrographs show some of the octahedral crystalline morphologies found during the sorting process.  By examining about 100 colonies within about 1 square mile and estimating the amount of soil sampled by the ants at 50 cubic feet (based on measurements from an exposed ant nest), about 5000 cubic feet of soil was sampled in looking for crystals.  No more than about 20 grams of crystals were recovered and of those only 3 showed clear octagonal crystalline structure.  Not a very good yield and lots of work for very little return, but the utility of harvester ants as an indicator species made the effort worthwhile.

While some may have heard the story of the great diamond hoax of 1872 all these stones were collected from around the estate, but one has to be willing to kneel in active harvester ant colonies to collect these tiny crystals.  You can find almost anything in the boot heel of New Mexico, if you have eyes to see.

A photomicrograph of clear crystals from harvester ant colony mounds.

Octahedral crystals.

Octahedral crystals from harvester ant nest mounds.

More Gifts From the Ants.

While testing the idea of harvester ants as a rangeland health monitor species, small crystals from the ant colony mounds were collected and sorted.  Below are small (~3 mm) specimens of chalcedony found outside colony entrances.  The image was taken using a digital dissecting microscope.  While the second image is the same grouping but photographed under UV light with a camera.  Note several of the chalcedony pieces fluoresce with a greenish light.  This behavior was also noticed in larger chalcedony specimens collected from the high New Mexican desert around the Painted Pony Resort.

Chalcedony specimens collected from the mounds surrounding harvester ant colonies.

The same grouping of chalcedony but under UV light.

Harvester Ants as a Rangeland Indicator Species

Ants, especially harvester ants utilize seeds as a food source and might be a useful indicator species for the grassland restoration efforts at the Painted Pony Resort.  A number of reports suggest that both soil composition and grazing intensity can alter harvester ant colony frequency on the landscape (1, 2, 3). Variation in ant colony density across the estate was noted while preparing a previous post on indicator minerals in ant colony mounds so a small comparative study was designed to test the hypothesis that harvester ant colonies varied with the grazing intensity on the estate.  A 3 km transect across the estate from west to east, starting on grazed New Mexico State land was chosen and at 14 stations a 30 m diameter circle (area = 730 meters²) was examined for harvester ant colony entrances.  A colony was defined on the basis of a circular pile of small (1-2 mm) stones, and an entrance hole with or without harvester ants on the surface. Although other ant species were observed along the transect these were not included in the colony totals.
Constantly grazed land had a average of 1 colony/730 m² while ungrazed land averaged 4 colonies/730 m² and there was a significant difference in the frequency of harvester ant colonies between the 2 grazing regimes, P = 0.003, single tailed t-test.  Since soil type also varies across the estate the number of colonies by soil type was also tested. Forest-Pinleno association is found on the west side of the estate while Eba very gravelly loam predominates the eastern portion of the estate. There was no significant difference in harvester ant colony density between these 2 soil types, P = 0.12, single tailed t-test. This suggests that soil composition, and secondarily plant species diversity, are not a major contributor to harvester ant colony frequencies on the estate in the semi-arid southwest, but rather the frequency of grazing (constantly grazed versus ungrazed land) is the more important determinant of harvester ant colony frequency in and around the estate.

Satellite view of the 756 acre Painted Pony Resort showing 3 km transect and locations of test sites.  The red line indicates the property boundary but no fencing and accessible to cattle, while the white line indicates fencing around the estate where cattle are excluded.  The 3 stations furthest west lie on New Mexico State land which is grazed year round.

Frequency of harvester ant nest colonies.

Soil map of the Painted Pony Resort.

Lunar Eclipse: Rained out in Southern New Mexico

All prepared for the big lunar eclipse but it was rained out.  The Painted Pony Resort received 0.21" from this late monsoon storm and it made viewing the event impossible.  I did manage a photograph just at moon rise as the full moon rose just over the mimetolith (stone face profile) in the Peloncillo mountains just south of Antelope pass in southern New Mexico.  Visible from the estate, this large stone face profile appears to be watching the full moon rise over awaiting the eclipse.  I felt very fortunate to walk outside just at the right time on an evening when the moon was full and positioned over the mimetolith, it was just the right combination of factors to get a unique image.

Looking at the Moon

Indicator Minerals and the Gift of the Ants

While ants are considered pests by many, their biology is of interest to many entomologists. In the desert southwest the Harvester ants of the genus Pogonomyrmex are a common occurrence on the landscape.  In fact at the American Museum of Natural History Southwest Research Station a yearly course on southwestern ants is taught.  Harvester ants nests are easily found since they occupy large open areas which the ants clear of plant material and the entrance mounds may be over a foot tall looking like small volcanic cones.  The detritus that makes up the mounds is a combination of excavated material from chambers in the colony, plant refuse, and other organic material.  Harvester ants colonies essentially sample the soil while building chambers within their nests by removing small gravel and dirt which is conveniently placed just outside the entrance for inspection.  The volume of soil sampled is a function of nest size and in the images below a profile of an abandoned nest over 4 ft in depth and 2 feet across resulted in a sampling of 50 cubic feet of soil.  These naturally produced soil samples are used by geologists in explorations for commercially important minerals and in Australia, ant nest mounds are explored to locate gold deposits.  Recent explorations of harvester ant nest mounds at the Painted Pony Resort did not identify any specific mineral deposits but did uncover some interesting crystals.  While small in size and not very common in nest mounds the crystals are quite beautiful with some interesting crystal structures. 

In the process of looking for nest mounds there seemed to be variation in the frequency of harvester ants colonies across the landscape and this may be related to landscape quality.  Areas to the east with little ground cover seemed to have fewer ant colonies while on the western side of the San Simon riverbed, where grazing is excluded, there seemed to be more colonies.  This observation suggests that harvester ants may be useful a proxy indicator species for range land health and an experiment to test this idea is under development. 

The surface expression of a large mature ant colony, probably leaf cutter ants.  The mound of excavated material is over 1 ft in height.

Underground expression of an ant colony.  Four foot deep and approximately 2' wide this nest sampled approximately 50 cubic ft of soil.

Ant nest, closeup of underground chambers.  Note the connections between chambers.

clear crystals from nest mounds.

More clear crystals from harvester ant colony mounds.  The rounded specimen in the bottom left is chalcedony which is weakly fluorescent.

Tumbleweed Cannoli

Cannoli are great Italian desserts with a fried pastry shell stuffed full of yummy filling but down in the bootheel of New Mexico there are not available, so we make do without.  In terms of landscape restoration though, the idea of a cannoli translates to another use for tumbleweed.  Tumbleweed is used in garlands on the Painted Pony Resort for arroyo stabilization and has been adapted for use in topsoil restoration barriers.  One of the problems with using annual grasses in topsoil barriers is their light weight.  With a wind storm the grasses become dislodged and move reducing the efficiency of the barrier.  But by wrapping the annual grasses, Amaranth and other weeds in a shell of tumbleweed the mass is heavier and stays put.  The natural stickiness of tumbleweed stems makes them ideal for wrapping the lighter grasses and weeds.   Below are 3 photographs of the process used to create tumbleweed cannoli.  Flattened tumbleweed is filled with annual grasses and then rolled allowing the tumbleweed shell to hold to itself.  The finished cannoli is then placed on the landscape as a barrier to catch sediment and create microhabitat for new grasses the next year.  It is similar in design to using rolled hay barriers but costs nothing in materials since everything is off the landscape.  Another example of using products of the land to heal the land and restore the landscape.

Flattened tumbleweed as the cannoli shell.

Annual grasses and amaranth as the cannoli filling.

A 5' long rolled tumbleweed cannoli ready for placement.

Rangeland Restoration: Mesquite Removal

While mesquite removal continues in the river bed in an effort to restore the area to open grasslands, mesquite removal began on the upper benches around the main complex of buildings at the Painted Pony Resort.  Because of deep taproots, mesquite is difficult to remove and experiments using the tractor required a second treatment with herbicide to completely kill the plant.  The Galion Grader, on the other hand, weighs 35,000 lbs and easily pulls the mesquite, taproot and all, out of the ground.  So after some modification to protect the hydraulic hoses, the machine was used to grub mesquite off the benches above the river bed.  Between 30 and 40 acres of mesquite were removed with the grader by the owner of the estate over a day of work.  The front tines were lowered and used to grab each plant and as the machine was moved forward the big diesel engine would provide enough power to pop most intermediate sized mesquites out of the ground.  So piles of uprooted mesquite dot the landscape at the moment but the material is being redistributed along the contours of the land to create additional topsoil barriers.  This spreads out the plant material allowing more rapid decomposition the creation of micro-habitat for the catchment of wind and rain blown seed and soil which will in turn provide new grass the opportunity to grow and spread over time.  With the establishment of new grass the tumble weed problem will slowly resolve itself since perennial grass cover will out compete the yearly tumble weed crop.

Intermediate sized mesquite with tap root and stringer roots.

Topsoil barrier created from grubbed mesquite.