American alligators are probably the best studied species of crocodilian, and there is a large amount of literature available on most aspects of its biology, behavior and ecology. Population surveys are extensive and ongoing, and data is available throughout the alligators' range due to links with management and harvest programs. While populations were severely affected in the early parts of the century (with protection occurring in the early 1960's), the recovery of this species has been remarkable in most areas thanks mainly due to properly controlled and monitored conservation and sustainable use (eg. tourism, harvesting) programs. The belly skin of the alligator produces a generally high-quality leather, and this resulted in considerable hunting pressure earlier in the 20th century, particularly in Louisiana and Florida. Even after hunting was prohibited in Florida, illegal poaching continued into the 1970s. Were it not for additional changes in the law to control the movement of hides, many think extinction may have been possible. Since then, populations have improved considerably and they are now only considered to be threatened in a few areas by habitat degradation, including water management programs.
In some areas, increasing alligator populations cause problems with human populations on the edge of alligator habitat, and "nuisance alligator" programs are required to deal with these cases. These involve catching and removing animals which have roamed too far into human habitation, or which pose a potential threat to people. Some animals are relocated, but this has generally been shown to be ineffective as alligators often return to their home range within a matter of days. Most recent "nuisance alligator" programs either sell the animals to a farm, or use their skins to help fund the program. Given the high degree of human-alligator contact, some attacks have been reported, but these are very rarely serious. There have only been a handful of alligator-related fatalities recorded in the United States since the 1950s, and improved education and awareness is the best long-term way to avoid future incidents. An increase in recent attacks have been attributed to illegal feeding of alligators, making them less wary of humans and more likely to attack instead of flee.
Alligators have been shown to be an important part of their ecosystem, and are thus regarded by many as a 'keystone' species. This encompasses many areas from control of prey species to the creation of peat through their nesting activities. Several other species benefit from the presence of alligator nests, not least the Florida Red-bellied turtle which incubates its own eggs there. The creation of 'alligator holes' is of great value not only to the alligators, but to the other species of animals which use them. For these animals, the value of the refuge outweighs any additional risks from their creators. Alligators in some areas are also showing greatly increased levels of mercury, an indicator of the state of the ecosystem. This may have long-term implications for their ability to reproduce, but the effects are still being quantified.