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.
Threats to Biodiversity. The primary threats to the savanna biome are humans (for example, poachers are killing elephants for their ivory tusks and hunting animals to the brink of extinction) and global climate change.
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.