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.

Summarizes the attached resource reports that have been submitted so far to help develop the SDCP within the watershed planning area of the Altar Valley. This initial presentation of resource information is intended to both educate and serve as an invitation to greater participation in crafting the SDCP.

Arivaca, located on the southern border of Pima County, is one of the few remaining riparian areas in southern Arizona. This report presents collected data, shows how the Arivaca area relates to the SDCP, and makes recommendations on how the plan could address pressing groundwater issues in the Arivaca Valley.

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.

A companion to the "Importance of Conserving Resources in the CIenega Creek Watershed" document and provides a focus on Altar Valley. This report includes detailed investigations into the historic conditions of the watershed, current rangeland conditions of biotic communities, and the environmental impact of a potential floodplain project.