The last flowering plant in CG1 put out its last anthers today (August 27, 2012). It had been flowering over a week longer than any of the other plants we monitor! This marks the end of the flowering season for Team Echinacea, but we’ve still got lots of work left to do!
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Happy Friday! Today was our fourth day “going solo” while Stuart is away in Chicago. In the morning, we finished up seedling searches at East Elk Lake Road. That’s two sites down! In the afternoon, we continued working on demography re-checks at some of the smaller sites. Basically, demography re-checks consist of fixing any errors that we might have made during the initial round of demography (i.e. one person said a plant had two heads while another said it had four), but it also allows us to go back and find basal plants that have flowered previously. By checking on these plants (or a random subset of these plants) each year, we can get a better idea of how often a plant flowers and the survival rate of flowering plants. Today we finished demography re-checks at Loeffler’s Corner (East and West) and Yellow Orchid Hill. Here’s a picture of the crew at Yellow Orchid Hill after a hard day’s work: The past couple of days have been lovely for outdoor work–sunny, cool, a little breezy. On Monday we said bon voyage to the Wagenius family as they prepared for their trip back to Chicagoland. Stuart will be back next week, but Gretel and the kids are done for the summer. Now there are five of us and no shortage of work to do. Monday morning we went to the site off of hwy 27 to take demography data on plants that flowered last year and reconcile errors from this year’s demography census. With two teams working with the GRS-1 GPS units, the task went quickly and smoothly. We spent Monday afternoon re-finding seedlings at KJ’s. This is a particularly challenging site because there is a high density of plants in a small area. We continued the endeavor this morning, and I’m happy to say are nearly finished. We should be able to defeat the beast tomorrow morning. Here are Jill and Maria looking for seedlings at KJ’s. Red flags mark completed focal plants. This afternoon we performed some routine maintenance of the main experimental plot, pulling out flags that marked plant we could not find. Then we spent the rest of the afternoon on individual projects. Karen Taira, who came up last week, has been spending her days working on her pollination experiment involving several species of Helianthus. Her field story of the day was that she found a pile of entrails next to one of her experimental plants. Apparently they were bigger than a prairie dog’s and smaller than a human’s. Perhaps it’s a new form of sacrificial sun worship–Praise Helianthus! Like their hosts, Echinacea aphids exhibit a strong seasonality. There’s a sharp rise in the frequency and abundance of aphid infestation followed by a rapid decline in early fall. That decline has occurred much earlier this year than last year. Fortunately, that has given me a chance to make some observations about what happens to aphids at the end of the summer. Here are a few things I’ve noticed: 1. Throughout my surveys in CG1 and several prairie remnants, I’ve noticed that the frequency of winged morphs has declined since July. Last week, I did not see any winged aphids, with the exception of a couple at East Elk Lake Road. This implies that dispersal declines as aphid numbers drop. 2. I and several others have noticed that aphids are starting to congregate at the base of the plant both at the petioles and at the base of the stem. I’ve also seen aphids crawling down beneath the soil surface and a few latched onto the tops of roots. One possibility is that as plants withdraw resources from their leaves, aphids move down the plant to follow their food source. I’ve also seen ants moving aphids at the base of the plant and placing them in dirt structures. These observations support the notion that aphids overwinter on Echinacea roots. Many aphid species in temperate regions spend the winter and summer on different plants. Their winter host is where they lay eggs and their summer host is where they feed and reproduce asexually. My guess is that Aphis echinaceae does not have a separate winter host. This plant at Nessman’s had a bunch of aphids congregated at the base. Notice the little green guys on the stem: This is one of the plants from my aphid addition/exclusion experiment in CG1. There are still aphids on the leaves, but most of them have moved to the petioles:
Here’s all of my data from my crossing experiment and the R script that I used to analyze it! I’ll put up a metadata sheet soon. Hallo once again from K-town! It was yet another wonderfully nice day out in the prairie of Minnesota. This morning, Maria and Katherine headed out to the Landfill site to GPS all of the flowering plants we found earlier (about 80 of them this year). Kelly, Jill, and I headed over to Around Landfill to do demography on the plants Kelly used for her phenology project. And Shona and Andrew won (at long last) a battle with our second GPS unit (which arrived yesterday), Chekov. Chekov has come to join Sulu in our endeavors to gain coordinates. But it’s best if both work properly. Oh, and Kelly’s last plant at all her remnants finished flowering today! It’s bittersweet. Title: Examining Pollen Limitation in a native prairie panic grass, Dichanthelium leibergii It has lots of cool pictures and Dichanthelium as the background! 🙂 See you at the symposium! Here’s the poster I will be presenting at the University of Minnesota on Thursday. So, a while back when GPS-ing the recruitment plots, there were a number of places where no nail was found in our initial survey. Here’s the list of those point numbers in the GPS: These were supposed to have nails, but we were unable to find them. Here’s an improved version of my poster on my pilot study of Dichanthelium germination, which I presented at the Undergraduate Research & Arts Expo at Northwestern. It’s pretty much the same content, but less text and neater. |
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