The park and the Athi-Kapiti Plains are linked by the migrations of wild herbivore populations. The plains to the south of the park are important feeding areas during the wet season. Before the city was established, herds of animals followed the rains and moved across the plains from Mount Kilimanjaro to Mount Kenya, a migration as great as the migration that takes place on the Serengeti. However, as the city grew the park became the northernmost limit of the animal's migration. Migrating animals can reach their southern pastures by travelling through the part of the Athi plains called the Kitengela. This land is very important to their migration routes, but growth in the human population and the accompanying need for land threaten to cut off this traditional migration route from the park to land further south. The park's migratory species are also threatened by changing settlement patterns, fencing, and their closeness to Nairobi and other industrial towns. These activities fragment their ecosystems and occupy their habitat.