California Tiger
Ambystoma tigrinum
Salamander
Threats During Subadult Migration & Hibernation Phase
By November the aquatic larvae should have matured to the extent that they can successfully transform into the terrestrial juveniles. These juveniles then must migrate to grasslands and oak woodlands, to hibernate for the winter. This can be extremely dangerous to Tiger Salamanders. As Tiger Salamanders migrate to these areas, they are faced with threats from urbanization and habitat fragmentation. Due to habitat fragmentation, the salamander may travel far distances to find a wooded habitat. Landowners and developers are the biggest threats to Tiger Salamanders (California Tiger Salamander, 2012).
Habitat Fragmentation
Habitats are often isolated and cut off from one another by the roads and highways that now run through them. Removing members from breeding populations greatly limits reproductive output, this makes it incredibly hard for salamander numbers to rebound. This threatens the Tiger Salamanders who can be run over by cars while crossing roads, brutally killed in an attempt to find a home for the winter. If a tiger salamander safely arrives in their new habitat, their next mission is to find a place to live underground during the winter to protect them from the cold, usually in the burrows of rodents.
Burrow Homes Lost
The loss of small mammals is mainly due to humans being angry and abusing small mammals. This includes killing gophers for going into gardens, or killing rats with the poison pellets. Small mammals are also at risk from being eaten by introduced predators such as cats. Because of concerns to cattle and agriculture, California ground squirrels are currently being controlled on over 4 million acres, a management practice that may indirectly harm California Tiger Salamanders (Redding, 2009).
All Terrain Vehicles
An additional threats to the Salamander during their time in woodlands is All-Terrain Vehicles (ATV's). At night, if it is moist enough, the salamanders leave their burrows in search for food. Many people who ride ATV’s head off of designated trails and trample through natural areas. Here salamanders that are hiding under leaf litter and other forms of natural debris are at risk of being run-over and killed (Redding, 2009).
They use these burrows for hibernation, shelter aestivation and shelter during the warm, dry months of summer and autumn. Because California tiger salamanders dig poorly, the burrows of small mammals are essential. A threat Tiger Salamanders face relating to this is the abundance of mammals in the areas they breed to provide a home for them (Cedlf, 2013). The Tiger Salamanders mainly depend upon the upland burrows of California ground squirrels and Bota’s pocket gophers, a parasitism relationship between the salamanders and mammals. This is because salamanders use toxins secreted from their skin to harm the mammals whose burrows they take.
