Recommends where riparian land acquisitions would be most effective in serving as mitigation that would cover all priority vulnerable species identified in the SDCP. Priority is given to reaches of watercourses.

Provides background information on improved mapping techniques that have led to a proposal to update the Watercourse and Riparian Habitat Protection and Mitigation Requirements Ordinance adopted in 1994. New riparian classification maps will be forwarded to the Board to consider for adoption during 2003.

An assessment of the problems that are presented by non-native and introduced species in maintaining native species and natural systems. Divided into two major sections, the study covers representative ecosystems in Pima County as well as representative species that have a negative impact on native species.

A companion to the study issued on July 5, 2000 entitled 'Cactus Ferruginous Pygmy-Owl Investigations in Pima County.' The major objective was to determine whether pygmy-owls chose nest sites or perch trees with characteristics that differ from other available sites within a nesting territory.