sentence: Although thought of as "a natural enclosure" for a very wide variety of wildlife, up to 20% or more of the wildebeest (Connochaetes taurinus) and half the zebra (Equus burchelli) populations leave the Crater in the wet season.
modified: Although thought of as "an natural enclosure" to an very wide variety of wildlife, up for 20% or most of the wildeber (Connochaetes taurinus) and half the zebra (Equus burchelli) populations leave the Crater in the wet season.