Invasive Species Threat: the Feral Pig

In the Pantanal, there are two species of naturally occurring pig-like mammals: the white-lipped peccary and the collared peccary. However, 200 years ago, farmers in the Pantanal introduced the Feral Pig, a nefarious invasive species around the world, to the area. The Feral Pig has brought ecological disaster to other areas into which it has been introduced, eradicating local occupants of its ecological niche and altering a landscape's vegetation. Thus, zoologists speculated that the Feral Pig would compete with the two Peccary species in the Pantanal due to their physical similarities and similar range. 

Feral Pigs

Collared Peccary

White-Lipped Peccary

However, a 2011 study of fecal analysis and geographical encounter rates revealed that niche partitioning prevents feral pigs from displacing the native peccary species. Geographically, the peccary's range differed from that of the pigs because the pigs tended to favor "floodable" habitats while the peccaries gravitated towards drier areas. This difference likely corresponds with physiological differences between the two groups, since the peccaries can more efficiently concentrate their urine to conserve water while the pigs have to stay near a body of water to reach their necessary daily intake of water. Feral pigs also lack sweat glands, so floodable habitats help them to regulate their body temperature. In terms of food, the Feral Pigs had a more restricted diet of fruits, mostly relying on the fruit of the palm Attalea phalerata, than did either Peccary species. The researchers proposed that digestive tract differences were responsible for these dietary choices. 

Because the Peccary species have more overlap with one another than with the Feral Pigs in terms of range and diet, the Feral Pig does not pose a significant threat to their wellbeing. However, as an invasive species, the Feral Pig does still threaten the Pantanal ecosystem by consuming local species' eggs, destroying vegetation by uprooting and harboring disease. Furthermore, increased pressure from cattle ranchers could force more overlap between the Peccary and Pig lifestyles, making their continued coexistence uncertain.

Sources:

• http://www.jstor.org/stable/info/30224446?&Search=yes&searchText=pantanal&searchUri=%2Faction%2FdoBasicResults%3FQuery%3Dpantanal%26amp%3Bacc%3Don%26amp%3Bwc%3Don%26amp%3Bfc%3Doff%26amp%3Bsi%3D51
• https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkLAdjSnHkuRVl3PAqRux9MaVCUpxQk9WWTnJvse46ALV-KlkIJUKnSgsqrwvboORymfamUaE9UR-JYeMP1wFsO5foZuscryrdHx5k8zoAmRhJHgDpSqHDxLAgrtJ2tUOy3sOZudU3CSE/s1600/collaredPeccary.jpg
•  http://cdn.roughguides.com/wp-content/uploads/2012/06/BAWYMH-1680x1050.jpg
• http://photos.zoochat.com/large/dudley0709_263-51637.jpg