After the boom-bust-boom of the fifties and sixties, the borough went into a third and more severe decline again in the mid-1970s along with much of the Rust Belt so that population was just 2,804 at the 2000 census. Now in the 2011 Brownsville still has a handful of buildings condemened or just borded up.
One threat to these Savanna biomes is the animals which graze upon it. Other biomes such as Taiga or Rainforest have a high tree quantity which means that less grass is able to grow for animals to graze on. However, since Savannas have few trees and much wide open space than other biomes an herbaceous layer grows much easier.
The effect of removing a top predator from an ecosystem is felt throughout the community. A great example is how wolves have been reintroduced to Yellowstone National Park . Another example of a keystone species that is not a top predator is the elephant living in savannas. Because these elephants consume small trees, they prevent the trees from spreading and multiplying across the savanna. If this were to happen, the savanna would change, having more trees and less grass.