The (Foot)Hills are Alive
On a hike or a ride in our foothills, you don’t normally encounter Julie Andrews or hear much that sounds like music. You see rocks and a lot of bare ground separating mostly small plants. Animals seem scarce, and mostly flying, as if on their way to somewhere else. Sandwiched between the fertile valley floor below and the forested mountain slopes above, these hillsides look a bit impoverished, almost barren. Yes they are beautiful, and invitingly open, but not obviously a place that many living things would want to call home.
This has been the rap on deserts since the time when ancient humans started putting their complaints in writing. And it’s true to a degree, for some kinds of living things. For many others, however, places like this are Home Sweet Home, and not just figuratively. For example, the sugary honeydew secretions of aphids and other sap-sucking insects support a complex ecosystem that is literally rooted here, because these insects feed on the roots of long-lived plants such as Gambel oak (Quercus gambelii). People don’t notice this ecosystem because most of its animal members are very small and underground, except at certain times of year, and even then mostly at night.
We are naturalists who frequent the Avenues and Tomahawk foothills, and Jack is an expert on the ecology and evolution of ants. He’s been checking them out for the last decade. To observe them hard at work you need to stop, kneel, and patiently look for them in leaf litter under the oaks (including in acorns) or under rocks in the spring (always put the rocks back!). To date Jack has found 37 different species. That’s 21% of the 174 ant species known to occur in the entire state of Utah. Given the tiny area covered by his survey, our local foothills would seem to qualify as a biodiversity hotspot.
Most of these ants depend directly or indirectly on the underground sap-sucking insects, which depend on legions of symbiotic bacteria that they culture inside their bodies to synthesize nutrients that don’t occur in the sugar water they get from the plants, which get their water from symbiotic fungi that extend their root systems for vast distances through the porous, rocky soil, and then use sunlight to turn that water and CO2 from the air into sugar. We walk on the sunbaked surface of that soil which, from our height, looks hostile to life. But just below our feet, a diverse and highly connected community carries on with the business of living well, in a world made sustaining and even comfortable by their own industry.
Jon Seger and Jack Longino
