Posts Tagged ‘monsoon’

Monsoon showers bring summer flowers

October 31, 2011

Last month, September 30-October 5, a group of fellow Portal enthusiasts (Zachary Brym, Katherine Thibault, and Christa Weise) got together at the site to take on not only the rodent survey, but also the summer annual and perennial plant survey. Each experimental plot (50 m X 50 m) also has 16 (0.5 m X 0.5 m) permanent plant sampling quadrats within it so that we can understand what changes might occur in the plant community from year-to-year or based on differences in what rodents might be munching or moving around their seeds. We weren’t sure that we could actually finish the survey between our schedule flights to Arizona, but found that a determined group of (mostly) mammalogists could actually do pretty well at identifying desert plants!

There doesn’t seem to be a great field guide for the plant occurring at the site (barely in Arizona, almost in New Mexico, and a desert transition zone…) but we compiled a small ‘library’ to take out with us including a mini-herbarium of plants pressed over the years, the Flora of New Mexico book, Flora of Arizona Book (Epple), and the Peterson Field Guide to Southwestern and Texas Wildflowers, and a Grasses of Arizona Book. We’d love to hear any suggestions for other guide books for the area, especially for grasses or non-flowering ID characters.

The weather was great and by working all day everyday, we were able to sample all our rodents (still a desert pocket mouse takeover) and get to all the plant quadrates with very few unidentifiable individuals! The area near the Chiricahua mountains seems to have gotten more monsoon rain that many other areas of southeastern Arizona, so there were quite a few plants to count relative to some other years, and I would guess (haven’t finished entering data yet!) that there were about 15 species of annual plants per plot. This is actually relatively high diversity for this site, since many years have less than 5 species present! Most common was the Summer Poppy (Kallstroemia grandiflora), Woolly Tidestromia (Tidestromia lanuginosa), two species of spiderling (Boerhavia intermedia and torreyana) and panicum grass (Panicum arizonicum and hirticaule). We tried to photo document everything identified (and unidentified!) and hope to update our mini-herbarium soon since many of the samples are becoming worse for the wear.

It was a lot of work and a cobbled together fast trip, but we sampled everything and had a lot of fun!

This is a photo of plot 16 showing the vegetation this year. It may look sparse, but its a lot more vegetation than in the last few seasons!

Pit tagging a small desert pocket mouse, Chaetodipus penicllatus.

Kate gets reacquainted with the rodents.

Working on identifying plants in a quadrat, with Christa Weise.

Using the herbarium cards to identify a more rare species this year, Euphorbia micromera.

This is an unidentified carpetweed, Kallstroemia spp. It was really common this year...Any ideas?

Some of the grasses are tricky! We brought back samples of this one, but couldn't decide if it was Eragrostis arid or intermedia. We left the site leaning more towards intermedia.

Zack Brym, Kate Thibault, and Christa Weise work hard on an especially grassy sampling site.

We were lucky to get showers each afternoon to cool things down.

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Summer in the desert

August 30, 2011

One thing that makes traveling to Portal each month so interesting is the speed at which the desert landscape can change. Southeastern Arizona has recently been in a major drought, but the arrival of summer monsoon rains seems to have helped green things up, at least temporarily.

Desert mushroom

Gopher snake on traps

Below, the first photo was taken on July 2, 2011 and the second photo was taken August 6, 2011. During that month approximately 11.4 cm of rain fell and transformed the dry, dusty ground into a carpet of green seedlings and flowers.

Some areas were covered in orange flowers (e.g., summer poppies, orange flame flower, and showy flame flower), purple flowers (e.g., silverleaf nightshade) and large caterpillars were abundant (I think mostly Sphinx moths).

In addition to the growth of new plant life, the summer rains have also led to flooding in the Chircahua Mountains where the fire left slopes unstable and vulnerable to washing away. Some of the forest roads remain closed and a short drive into Cave Creek Canyon makes it easy to see areas where the forest floor is buried under mud and debris washed down by flash flooding. Some locals, bloggers Azure Gate and Cave Creek Ranch, have posted updates and photos on conditions in the area.

In addition, the dry soil conditions and lack of vegetation on the bajada and in the valley seem to have allowed for increased erosion at our site as well. The gravel roads leading towards the Portal Project were washed out in places and erosion around the fenced plots meant that some gates were left > 12 cm above the actual soil surface or buried underneath mud and debris; both scenarios making it difficult or unlikely for rodents to actually find and use the gates. I’ll have to work at maintaining these gates over the next month as more rains are likely to occur.

Luckily, I had lots of help digging out rodent gates and collecting data by Elita Baldridge, a Ph.D. student in Ethan White’s lab who came to help out before we both headed to present at ESA after field work was finished.

I continue to be amazed at the “sea” of desert pocket mice (Chaetodipus penicillatus) that seem to be taking over–we’re even encountering control plots, where kangaroo rats should be dominant, with no kangaroo rats at all! Amazing.

Oh, and speaking of amazing…