This is not really a problem with urbal sprawl. We are not invading their territory as much as they are invading ours. Up until the 1940s or so, people were encouraged to kill lions, bears, falcons, eagles, wolves, and coyotes. The consequences of that being that there were very few left, confined to our parks. For the past several decades we have switched to extreme protection, with the result that they have come back out of the parks into any land they can find food. Places like Kansas are starting to see lions for the first time in a hundred years.
As for the special case of lions, we need to keep in mind their instincts. Lions are territorial, they stake out land and kill any lion they find inside it, even their own grown offspring. When lions move into a city it generally means there is no unclaimed territory left in the area. Relocation is not much of an option anymore.
Agreed. The Jet Propulsion Laboratory sets up against the San Gabriel Mountains, between Pasadena and LaCanada. The area above the lab is National Forest, and building is restricted. The area below the lab is the start of the aroyo that a mile further widens into the valley where the Rose Bowl sets. The first part of the arroyo is part of a flood control area that is fairly natural. Lions have been spotted there in the past month, for the first time in a very long time.
Because of this, we have started teaching the Cub Scouts in the area how to react to a lion if they come across one (e.g., make yourself look as big as you can). This is a case where the lions are coming out of the wild and into the urban environment. We can just hope that we don't have an incident in the coming years -- before the kooks in this state come to their senses and realize that the "save the lions" initiative needs to be repealed.