Determining Vulnerable Species
Within Pima County, Arizona

This document was initially drafted by County staff and Dr. Bill Shaw from the University of Arizona in order to facilitate discussion about which species might be considered for protection under the Sonoran Desert Conservation Plan. The report compiles information on plants and animals that are already recognized by the federal government as imperiled species, species which have been extirpated, and a much larger number of species that are in decline either locally or nationally. Descriptions of status, location, distribution and habitat needs are presented for each species proposed. The report also considers vegetative communities, their history of decline and modification, and recommends priorities for their protection. The information is based on interviews with members of the local science community and reviews performed by members of the Science and Technical Advisory Team (STAT) between March and November 1999.

While reading through this report, one should be aware that the authors do not present a full list of species whose existence is considered vital to the natural ecosystems within Pima County. This report was written to provide the initial frame of reference for the development of a work plan for conservation of Pima County's native plants and animals. Numerous changes have been made to the report to this date, and most likely more changes will occur before recommendations are made to the Steering Committee about what species should be covered for the purposes of any incidental take permits issued as part of the Sonoran Desert Conservation Plan.

TABLE OF CONTENTS

Some of these pages link to files in PDF format. Acrobat Readers for viewing these files are free and available for download from Adobe Systems Inc.

   1.0    INTRODUCTION

1.1     Background

1.2     Setting

1.3     Environmental History

1.3.1  End of the Glacial Period

1.3.2  Arrival of Ancient Peoples to the New World

1.3.3  Human Population Increase in Historic Era

1.4     Information Needs

1.5     Purpose

   2.0    METHODS

2.1     Previous Studies

2.2     Interview Process

2.3     Species Database

2.4     STAT Review Process

2.5     Supplemental Information

   3.0    SPECIES EXTIRPATED FROM PIMA COUNTY

   4.0    VULNERABLE SPECIES IN PIMA COUNTY

   5.0    HABITATS OF CONCERN AND TARGET PLANT COMMUNITIES

   6.0    OTHER SPECIES DISCUSSED

   7.0    PEST SPECIES FOUND IN PIMA COUNTY

   8.0    DISCUSSION

8.1     Keystone Species in Pima County

8.2     Flagship Species in Pima County

8.3     Umbrella Species in Pima County

8.4     ESA Conservation vs. Unlisted Species Conservation

8.5     Conservation of Species vs. Habitat Conservation

8.6     Species vs. Subspecies

8.7     Taxonomic Uncertainties

8.8     Other Issues

   9.0    RECOMMENDATIONS

9.1     STAT Goals and Objectives

9.2     STAT Recommendations

   10.0   REFERENCES

   FIGURES

1     Location Map

2     Comparison of Aquatic and Semiaquatic Habitats before 1890 and Today (PDF document)

   LIST OF TABLES

1     Federally Listed, Proposed and Candidate Species

2     People Interviewed for Species of Concern

3     Species Extirpated from Pima County

4     Vulnerable Species in Pima County, Arizona

1  Species at risk for whom habitat in Pima County is crucial for their existence

2  Species at risk and/or are generally declining throughout their range

3  Species that are rare in Pima County, but the overall status is unknown

4  Species at risk in Pima County, but are not at risk overall

5     Habitats of Concern & Target Plant Communities

   APPENDICES

A     Additional Species & Interview Process Forms (PDF document)

B     Other Species Discussed

C     Pest Species Found in Pima County

D     Keystone Species in Pima County, Arizona

E     Flagship Species in Pima County, Arizona

F     Umbrella Species in Pima County, Arizona