The newest artillery in the arsenal of Saguaro National Park rangers is the size of a grain of rice and will be delivered, not with a rifle, but with a hypodermic needle.
The weapon is being used in an effort to prevent cactus rustling. The mighty saguaro cactus has become a favorite target of thieves who steal small plants to sell for landscaping. Saguaro National Park rangers are hoping that a tiny microchip inserted into a cactus will deter thieves from stealing them.
Driving through the Sonoran Desert, you can see hundreds of cactuses marching up the hillsides, many of them passive sentries to events that took place in the desert a century ago, as the stately symbol of Arizona can live for more than 200 years.
Why then the rush to protect them from thieves? Surely there are enough to go around.
Not so, say plant experts. Although it looks as if the supply of saguaros is infinite, natural enemies could eliminate the saguaro if they are not closely monitored. The park has little control over the cycles of summer heat and winter freezes that routinely take their toll. Saguaros may die of old age, but they also die of other causes. Animals eat the seeds and seedlings, lightning and winds kill large saguaros, and severe droughts weaken and kill all ages. Wildfires could wipe out the entire population in one mighty conflagration.
From the beginning the saguaros struggle to survive. Of tens of thousands of pinhead-size shiny black seeds one adult plant can produce in a year, very few will make it to adulthood. Rodents, birds and other animals scarf up the seeds that have not fallen under rocks or other plants that help protect them.
The seeds that do survive grow very, very slowly. After one year, it may have grown only a quarter of an inch and may take 15 years to grow a foot tall. It takes 30 years for a saguaro to produce fruit and seeds and 50 years for it to grow to 7 feet. And the arms that define the saguaro? They don’t sprout until the plant is a venerable 75 years old.
By 100 years the saguaro may reach 25 feet. Saguaros that live 150 years or more attain the grandest size, towering as much as 50 feet and weighing 8 tons, sometimes more, dwarfing every other living thing in the desert. These are the largest cacti in the United States.
Because of these characteristics, it is very difficult to grow a saguaro in a nursery. But since the plant is prized for landscapes, it is very desirable, hence its allure for plant thieves.
But theft is only one of the threats the encroaching human population presents to the saguaro. Livestock grazing devastated some cactus forests. Seedlings were killed outright by trampling, unable to find suitable places to grow because the ground had been compacted and nurse plants killed. The cactuses compete with humans for that most essential need of any living thing in the desert – water.
Today, although grazing has been eliminated, natural forces, vandalism, and thievery continue to take a toll on the park’s saguaro forests.
The microchips
The microchip that will be used by the Park is similar to those used to identify dogs and cats.
The chips would help in investigations, such as a January 2007 theft when 17 saguaros were stolen, but their main value is deterrence. Part of the program may include spot checks at nurseries, which sometimes buy plants from the rustlers.
The chips, that will be inserted into 4-to-7-foot cactuses near the road, can last more than 100 years, said a representative for Biomark, the chip’s manufacturer.
Even private landowners would be well-advised to salt their saguaros with microchips. When the Tucson Water company installed several cactuses in front of its headquarters recently, they disappeared overnight.
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