Sunday, October 28, 2007

Semi Arid Grassland

About an hour's drive southeast of Tucson there is a beautiful grassland community known as the Las Cienegas National Conservation Area. It is on the edge of the Sonoran desert, and is an area of gentle rolling hills. Mesquite tress have been invading the grassland, and the BLM has tried to remove the trees by controlled burns, and mechanically removing them with bulldozers. One of my friends Danielle, has been looking at how these methods affect the small mammal populations in the grasslands. I had the chance to help Danielle and her friend Eric during one day of their work. One of the rodents caught in a live trap Danielle, and Eric set. In each plot there were 100 traps set, and in many of the plots over 90% of the traps had animals in them when we checked. The traps are baited with bird seed and checked early the next day. Any captured animals are identified, and sometimes measured and marked, then released where they were caught. Kangaroo rats are especially adapted to dry conditions in that they never have to drink. They get all the water they need from the seeds they eat. Their kidneys are much better at conserving water than those in other mammals such as humans. One kangaroo rat built this mound and the paths leading to it. A bit of care must be taken when handling the animals as they will bite!

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