various forms. Related to water habitat, there is drying of wetlands, clearing of aquatic logs or rocks (basking sites), and clearing of shoreline vegetation, which allows more predator access or increased human foot traffic. Related to nesting habitat, urbanization or planting can remove needed sunny soils. Another significant human impact is roadkill—dead turtles, especially females, are commonly seen on summer roads. In addition to direct killing, roads genetically isolate some populations. Localities have tried to limit roadkill by constructing underpasses, highway barriers, and crossing signs. Oregon has introduced public education on turtle awareness, safe swerving, and safely assisting turtles across the road. In the West, human-introduced bass, bullfrogs, and especially snapping turtles, have increased the predation of hatchlings. Outside the Southeast, where sliders are native, released pet red-eared slider turtles increasingly compete with painted turtles. In cities, increased urban predators (raccoons, canines, and felines) may impact painted turtles by eating their eggs. Other factors of concern for the painted turtles include over-collection from the wild, released pets introducing diseases or reducing genetic variability, pollution, boating traffic, angler's hooks (the turtles are noteworthy bait-thieves), wanton shooting, and crushing by agricultural machines or golf course lawnmowers or all-terrain vehicles. Gervais and colleagues note that research itself impacts the populations and that much funded turtle trapping work has not been published. They advocate discriminating more on what studies are done, thereby putting fewer turtles into scientists' traps. Global warming represents an uncharacterized future threat. As the most common turtle in Nova Scotia, the eastern painted turtle is not listed under the Species at Risk Act for conservation requirements. Pets and other uses According to a trade data study, painted turtles were the second most popular pet turtles after red-eared sliders in the early 1990s. As of 2010, most U.S. states allow, but discourage, painted turtle pets, although Oregon forbids keeping them as pets, and Indiana prohibits their sale. U.S. federal law prohibits sale or transport of any turtle less than , to limit human contact to salmonella. However, a loophole for scientific samples allows some small turtles to be sold, and illegal trafficking also occurs. Painted turtle pet-keeping requirements are similar to those of the red-eared slider. Keepers are urged to provide them with adequate space and a basking site, and water that is regularly filtered and changed. Aquatic turtles are generally unsuitable pets for children, as they do not enjoy being held.