Conservation of Kangaroo Rats
|Kangaroo Rat Conservation|
Ecological Importance of Kangaroo Rats
Kangaroo rats serve as a keystone species in many of the desert habitats in which they live (Williams et. al., 1998). Dipodomys play vital roles in these communities by heavily influencing other animal populations, soil quality (from burrowing and foraging), and plant distribution. Kangaroo rats present strong competition against competing granivores and against other animal species threatening its mound region (Valone et. al. 1995, Waser & Ayers 2003). Dipodomys also support other plant and animal species such as arthropods, birds, fungi, and other small mammals, as their burrows provide shelter and dropped or leftover food is used by other organisms (Waser & Ayers 2003). Physical disturbance of the ground by Kangaroo rat burrows also affect species distribution and vegetative cover of plants surrounding them (Valone et. al. 1995). Collection of seeds from larger plants further affects plant communities, allowing for smaller plant species to compete with larger ones. (Waser & Ayers, 2003).
Current Status of Kangaroo Rat Populations
Kangaroo rat populations in the Southwestern United States have been severely threatened over the last fifty years. Until the 1950's, Kangaroo rat populations thrived in Southwestern United States and Northern Mexico. However, in the last half of the century, populations became greatly decreased and fragmented. (Williams et. al., 1998). Currently six species of Dipodomys are listed as endangered, and many other species' populations are rapidly declining. (Threatened and Endangered Species System, 2005).
The most important cause of this decline has been habitat degradation. This degradation is a result of mainly human development (Williams et. al., 1998), with changing weather patterns also having an effect. As agriculture and irrigation increased rapidly during the 1960's, Dipodomys native habitats were drastically changed and often destroyed, and efforts to exterminate rodents further reduced population sizes (Williams et. al., 1998).
Efforts to Conserve Kangaroo Rat Populations
As Kangaroo rats have been identified as keystone species, and several of these species have been listed as endangered, strong efforts have been initiated to maintain and restore kangaroo rat populations. The main focus of conservation efforts have been to protect existing habitat in order to minimize further damage to populations.(Williams et. al., 1998). Furthermore, efforts to restore damaged habitats and enhance existing habitats are being made. Human developments such as gravel roads have been shown to hinder Kangaroo Rat movement, and efforts have been made to utilize less damaging dirt roads through Kangaroo Rat habitats (Brock & Kelt, 2004). Studies have found that removing shrubs from desert environments improves the survival rate for Dipodomys (Figure 1). These findings indicate that shrub control could benefit kangaroo rats and increase population sizes. (Price, et al., 1994)
Increased research and monitoring of kangaroo rats and kangaroo rat populations will increase our knowledge of how these rodents interact with their environment and how we can preserve these important and fascinating animals.
Figure 1. Number of Kangaroo Rat individuals found before and after removal of shrubs in experimental and control plots. The Figure shows that Kangaroo Rat populations significantly increased in plots in which shrubs were removed.
Adapted from (Price et. al., 1994)