July brought us over six inches of very welcome rain! The summer monsoon – one of five distinct seasons here – has returned to southern Arizona after a two-year near-absence. Purple martins are cruising above the treetops and a family of Mississippi kites has been visiting us for days. We are seeing rattlesnakes on a daily basis. On sultry, warm nights, elf owls have been calling in the wee hours of the morning. Saguaros are fattening as they transport water in their tissues. Native grasses are sprouting. The land and its life are rejoicing.
The changes on the landscape are incredible, happening with amazing rapidity and soaring fecundity. The mesquite bosque surrounding our home had been without a green understory during the entire past two years. Not any more! One glance out the window reveals a near-jungle of dense greenery standing five feet tall – much of it composed of one dominant plant with the unflattering common name of “pigweed.”
Pigweed is known to botanists as Amaranthus palmeri, and it is certainly not a “weed.” In the conventional sense, most of us consider weeds to be troublesome non-native plants. This one is a native species, and its presence speaks of great benefits to the land and its wildlife.
One of the primary winter forage plants for the deer that inhabit this river valley is pigweed. A good source of winter forage is critically important to wild ungulates. Rabbits, hares, javelina, and many rodents feed on the green plants in summer. Once the seed heads form, they tend to remain through autumn and winter on dead, standing plants. Great numbers of various species of sparrows winter in southern Arizona. The seeds of pigweed are heavily fed upon by many of these sparrows and other native birds as well. Something that is very obvious, but often overlooked by many people, is the fact that the dense stands of pigweed are shading the ground. I can’t stress enough how important shade is in desert ecosystems! The ground retains much more moisture and soil temperatures are far lower, allowing fungal hyphae and numerous other microflora and microfauna to work in shallower horizons of the soil. This benefits all life.
The summer rains bring many creatures out of hiding. Among these are toads, countless insects, red velvet mites, and the largest millipedes living in the United States…
For many of our of native amphibians, monsoon rains furnish their only chance to reproduce successfully. A strong population of spadefoot toads inhabits this valley, but they remain completely sequestered until strong summer rainstorms bring them up from their deep underground burrows. On July 3rd, the first monsoon storms rolled in – a succession of two storms with plenty of lightning and life-giving rainfall. That night, the landscape was ringing with the voices of hundreds upon hundreds of spadefoot toads.
