The spread of invasive species creates serious environmental problems as well as economic hazards for residents and will hamper implementation of parts of the SDCP.

To facilitate development of the Environmental Impact Statement which must accompany the Section 10 multi-species conservation proposal, a series of issue papers is being published. This study discusses water resources in the context of the alternatives being considered to date.

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.

Provides a brief discussion of the need for the federal government to afford special protection for the Ironwood forest found in the Ragged Top and Silverbell Mountains. A proposed Ironwood Preserve would conserve one of the most valuable stands of the ancient Ironwood forest within the Sonoran Desert ecoregion.

Brings together the findings of previous reports and suggests policies to address water quality issues in Pima County.

Compiles water quality data for the streams that have been identified as priorities and assesses land uses and potential pollution sources that might impact the water quality of the highest priority aquatic habitats.