Hurricane Katrina's aftermath definitely earns the spot as the 3rd most intense United States land falling tropical cyclone. It's violent outcome left biodiversity and biotic and abiotic life in New Orleans a bit, quite a bit torn up.
Hurricane Katrina formed by using hot humid air that rises to the top of the storm. As the air moved closer to the top, it cooled and condensed. When the water vapor condensed, it generated rain or in Katrina's case, a tremendous downpour as well as heat.
The Violent raging storm hit New Orleans through August 23rd-31st, 2005
The environment before hurricane Katrina was fair. Plants growing, Animals living, houses standing up.
The environment after Hurricane Katrina was another story... Some much downpour there were animals dying, plants washing away, and peoples houses on the ground.
Abiotic factors were affected tremendously. Houses were knocked down, streets were flooded, signs knocked over, and even car crashes.
Yes, it has changed biodiversity in many ways. Before you could look and see many animals living and now you look and see a terrifying environment with so many organisms (biotic or abiotic) either not living or knocked over/Broken.