Temperature Records

Blue Jay Barrens has been the site of many scientific inquiries over the years.  Researchers have visited to collect data on such things as magnetic anomalies, bedrock patterns, amphibian distribution and ant behavior.  The latest endeavor, a two year collection of air and soil temperatures, has just been completed.

Personnel from the Missouri Botanical Garden placed these temperature sensors in some of the barrens of Blue Jay Barrens to capture data on the microclimatic conditions of these unique ecosystems. Air temperature data was collected by sensors located near the top of a 5 foot aluminum rod. The sensors were shaded by two white plastic discs. The largest disc set at the highest point of the apparatus, while a smaller disk set a couple inches below that. Both discs functioned to provide shade for the sensors. The gap between the two discs was to allow air circulation so that neither blazing sun nor cap of snow would influence the air temperature sensors.  Soil temperature sensors were placed near the base of the aluminum rod, at a depth of approximately ¾ of an inch.

I knew that the unprotected soil of the barrens had always appeared to be baking in the summer sunshine.  The soil temperature readings provided data to which I had not previously had available. During a two-year period there were 105 days where the soil temperature exceeded 100° F. The highest soil temperature recorded was just above 120° F.

Blue Jay Barrens was chosen as a site for this temperature study because of this plant, Leavenworthia uniflora.  This area is close to the northeastern most limits of this species range. The species itself is being studied with the expectation that it may be an indicator of how rare plant species react to changing climate conditions. The Leavenworthia cooperated by producing outstanding crops in the vicinity of the temperature sensors.  Leavenworthia seeds need to go through a period of heat before breaking dormancy.  It appears that any seed spending the summer on the barrens is going to get all the heat it needs.

The air temperature sensors were contained within orange balloons held in place by rubber clips. Even though they were protected from direct sunlight the balloons deteriorated dramatically over the course of a single year.

As I was gathering up the equipment in preparation for shipping the sensors back to the Missouri Botanical Garden, I noticed a small jumping spider perched beneath the plastic disc.

At first glance it appeared to be a typical, healthy spider. Although, I couldn’t remember a species that exhibited a yellow abdomen.

A closer examination showed that the yellow was not a part of the spider at all. That, and the fact that the spider was not moving at all, cause me to reevaluate my assessment of its health.

The spider has been long dead. It probably died sometime last fall. The fuzzy yellow substance covering the abdomen is a fungus. It looks quite similar to the zombie fungi that attacks various insect species. This is the first time I’ve seen a spider that seemed to be afflicted by the same ailment.