People and other animals share some basic needs.
Every animal needs a place in which to live.
An animal's habitat includes food, water, shelter and space in an arrangement appropriate to the animal's needs. If any of these components of habitat is missing or is affected significantly so that the arrangement for the individual animal or population of animals is no longer suitable, there will be an impact. The impact will not necessarily be catastrophic, but can be. There are a great many additional limiting factors beyond those of suitable food, water, shelter and space. For example, disease, predation, pollution, accidents and climatic conditions are among other factors which can have impact.