Often the political boundaries of states and countries do not align with any biologically relevant boundaries, and so species often occur sporadically or rarely in one state, while being extremely abundant in an adjacent state. These species are considered “peripheral species” and are often derided by developers and biologists alike as being unworthy of special regulatory protection.
Fraser, D.F. 2000. Species at the edge: the case for listing of “peripheral” species. pp 49-53 in L.M. Darling (ed.) Proceedings of a Conference on the Biology and Management of Species and Habitats at Risk.