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.
A savanna or savannah is a grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close.ometimes midwestern savanna were described as grassland with trees. Different authors have defined the lower limits of savanna tree coverage as 5â10% and upper limits range as 25â80% of an area. Two factors common to all savanna environments are rainfall variations from year to year, and dry season wildfires.