Two days before the tornadoes, our field ecology class went out on our second trip to Strawberry Crater northeast of Flagstaff (north of Sunset Crater National Monument, east of Hwy 89). For our second project our crew was initially doing a follow-up of an unpublished study done in this class in 1992 that looked at whether or not the large powerlines running through the site were providing additional stress to that of the poor-growing conditions of the cinder soils that were causing one-seed junipers (Juniperus monosperma) to have two-seeded cones. Producing more than one seed is due to "polyembryony", which is the production of additional embryos, which may have below-average seed weights. Typically, lower seed weight infers that the seed may not be viable, as weight is a measure of the amount of food that the growing embryo has to feed on before it can sprout and deal with environmental stresses below and above ground. By the way, junipers appear to have "berries", but they are actually fleshy cones with fused-together scales. We ended up not seeing a difference in the frequency of double-seeded cones growing under the powerlines vs. varying distances away from the powerlines. We initially presumed that the severe effects of the recent drought masked any effects of the electromagnetism that the 1992 study implicated as being an additional stressor causing the cone abnormality. As we continued through our study, we noticed other strange cone and seed features that made us rethink our research questions/hypotheses (discussed below). During this trip at the beginning of the storm system, we encountered lots of lighting and some brief downpours. It really made us feel safe sampling junipers below powerlines with lightning fairly close by! The lightning was cool to watch off to the west, as the sunset behind the clouds made the lightning have a pink-purple hue to it. Here are some photos of the site with the storm moving through:
The storms also dumped some snow on the higher elevations of the San Francisco Peaks above Flagstaff. Here are some shots from NAU and from north of Strawberry Crater to the northeast of the peaks:
So, after the powerline hypothesis didn't seem to be providing any pattern, we revised our study and decided to compare cones of junipers across an elevation gradient and between two different soil types (the cinder soils around Strawberry Crater and the more limestone soils east of Flagstaff near Cosnino). Along with looking at the frequency of two-seeded cones, we also noticed many of the cones on some trees having a peeled-back look, where the seeds were protruding out of the fleshy cones. Looking in the literature, a few old studies had discovered that this feature is called "gymnocarpy" and is caused by insect larvae invading the immature cones before the embryos are fully-developed. Typically gymnocarpous cones have infertile seeds. In addition, we noticed a high proportion of junipers with parasitic mistletoe (Phoradendron juniperinum), which we decided to quantify frequency of as we suspected it to be an additional stressor that could lead to higher numbers of two-seeded cones.
After quantifying these features, we finally started seeing some patterns. Two-seeded cones were more frequent on the very-stressed cinder soils than the less-stressed limestone soils. Frequency of gymnocarpy and mistletoe appeared to be correlated with elevation, having a higher frequency at lower elevations. We also found higher seed weights on less-stressed sites. Since the lower elevations where the ecotone between juniper woodlands and grassland are more stressed (less soil moisture, higher temperatures), this higher frequency of fewer viable seeds suggests that the juniper woodland at lower elevations on the Colorado Plateau may be undergoing a range contraction. Recent research looking at potential effects of climate change have suggested that plant communities may shift up in elevation. If droughts become more frequent with warmer average temperatures, then the pinyon-juniper ecotype may move up in elevation over time with higher mortality and decreasing recruitment of new seedlings at lower elevations. Anyways, here are various pictures from the project:
Gymnocarpous cones (note that the one on the left in the first picture has 3 seeds, which is very rare, although other studies have documented 4 seeds in some cones):
juniper mistletoe (Phoradendron juniperinum):
Ecotone between juniper woodland and rangeland:
Of course, whenever you do a field project you end up encountering a lot of other great stuff besides what you're directly studying. While I didn't get any good photos of birds there, we saw lots of Pinyon Jays and migrating Sage Thrashers in the pinyon-juniper woodlands. One day I almost stepped on a roosting Common Poorwill too (it flushed from right under my foot). Here are some photos of scenery, ancient indian sites, plants, and wildlife seen during our project around Strawberry Crater:
Views of Strawberry Crater, a relatively recent (but extinct) volcano and its cinder field:
Arizona gilia (Ipomopsis arizonica), which is related to skyrocket (I. aggregata), but is adapted to growing on cinder soils:
horned-lizard:
Ancient pithouse ruins and pottery shards left by Sinaguan indians:
Rusted coffee can hanging in juniper that a rodent or bird used as a nest:
Insect impaled on barbed wire by Loggerhead Shrike (a predatory songbird). They will impale insects, small birds, lizards, and rodents on sticks, yucca leaves, or barbed wire for later feeding:
purple locoweed (Oxytropis lambertii):
Apache-plume (Fallugia paradoxa):
View of Hopi mesas and Painted Desert to the northeast of Strawberry Crater:
rubber rabbitbrush (Chrysothamnus nauseosus / Ericameria nauseosa):
Road-kill elk along Hwy. 89:
Dead mouse and halloween-colored beetle that was feeding off it:
Noseburn (Tragia nepetefolia), a relative of stinging-nettle, that leaves a burning sensation for a couple hours if you touch it:
One of the other crews from our class was initially doing a study testing aggression in ants by dying some ants with a hot-pink powder and then releasing them into a foreign ant hill. We came across one of these hills and saw some of the dyed ants milling around:
Sunset and Brewer's Blackbirds perched on powerlines against the sunset:
The one day our crew was dropped off north of Strawberry Crater near a roadside trading post so we could sample junipers at lower elevations. So, when dusk came, we ended up waiting at the trading post for our professor and the rest of class to pick us up in the van. While we waited, we checked out some really old wagons next to the parking lot. We also noticed a very bizarre sign across the highway for "Widowsmite Mission". This became an ongoing joke throughout the project, as we weren't sure why the hell a church would want to smite widows. Here are photos of the wagon and the strange sign:
And lastly, here is a group photo of our crew (posing with a bag of juniper cones we were collecting), which besides myself included Jeff and Dana:
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