Colusa Subreach Planning Pest and Regulatory Effects Study Final Project Report January 2008 Colusa Subreach Planning Pest and Regulatory Effects Study Final Project Report Submitted to: Colusa Subreach Planning Advisory Workgroup and The Nature Conservancy 500 Main Street Chico, CA 95928 Contact: Greg Golet, Senior Ecologist 530/897-6370 Prepared by: EDAW 2022 J Street Sacramento, CA 95811 Contact: Ron Unger 916/414-5800 January 2008 05110133.01 01.30.08 TABLE OF CONTENTS Section Page ACRONYMS AND ABBREVIATIONS................................................................................................................iv EXECUTIVE SUMMARY ............................................................................................................................... ES-1 Background and Purpose of the Study........................................................................................................ES-1 Key Regulatory Findings............................................................................................................................ES-2 Key Pest Findings.......................................................................................................................................ES-5 Recommendations.....................................................................................................................................ES-11 Conclusions ..............................................................................................................................................ES-13 1 INTRODUCTION ...................................................................................................................................... 1-1 1.1 Background and Purpose of the Study................................................................................................ 1-1 1.2 Study Objectives and Design............................................................................................................ 1-15 2 REGULATORY CONSTRAINTS............................................................................................................ 2-1 2.1 Environmental laws and Regulations Relevant to Agriculture and Habitat Restoration in the Study Area .......................................................................................................................................... 2-1 2.2 Sensitive Biological Resources in the Study Area............................................................................ 2-12 3 REGULATORY SOLUTIONS ................................................................................................................. 3-1 3.1 Omitted Regulatory Solutions............................................................................................................. 3-2 3.2 Restoration Design Solutions.............................................................................................................. 3-3 3.3 Regulatory Agreement Solutions........................................................................................................ 3-7 3.4 Overall Evaluation of Potential Regulatory Solutions...................................................................... 3-17 3.5 Regulatory Solution Conclusions ..................................................................................................... 3-17 3.6 Regulatory Solution Recommendations............................................................................................ 3-19 4 AGRICULTURAL PEST EFFECTS AND CONVENTIONAL CONTROL MEASURES................ 4-1 4.1 Pest Effects on Agriculture in the Colusa Subreach ........................................................................... 4-1 4.2 Potential Pest Effect Changes from Riparian Habitat Restoration, and Conventional Control Measures ......................................................................................................... 4-5 4.3 Conclusions on Pest Species Effects................................................................................................. 4-38 5 PEST SOLUTIONS.................................................................................................................................... 5-1 5.1 Pest Prevention................................................................................................................................... 5-1 5.2 Pest Abatement ................................................................................................................................... 5-5 5.3 Coordination with Neighboring Property Owners.............................................................................. 5-6 5.4 Evaluation of Potential Pest Solutions................................................................................................ 5-7 5.5 Potential Pest Solutions Conclusions.................................................................................................. 5-9 5.6 Pest Solutions Recommendations ..................................................................................................... 5-10 6 DOCUMENT PREPARERS...................................................................................................................... 6-1 7 REFERENCES ........................................................................................................................................... 7-1 Colusa Subreach Planning EDAW The Nature Conservancy i Table of Contents TABLES 1-1 Land Use between the Flood Control Levees of the Colusa Subreach .................................................. 1-2 1-2 Proposed Restoration Sites..................................................................................................................... 1-5 1-3 Proposed Riparian Habitat Types........................................................................................................... 1-5 1-4 Proposed Restoration Tract Sizes and Adjoining Land Use Types...................................................... 1-14 2-1 Endangered, Threatened, and Fully Protected Species with Potential to Occur in the Study Area ..... 2-16 2-2 Potential for Increased Agricultural Regulatory Constraints Associated with Endangered, Threatened, and Fully Protected Species and Riparian Habitat Restoration in the Study Area........... 2-33 3-1 Evaluation of Habitat Type Configuration as a Solution to Increased Regulatory Constraints in the Colusa Subreach............................................................................................................................... 3-4 3-2 Evaluation of Planting Protocols as a Solution to Increased Regulatory Constraints in the Colusa Subreach..................................................................................................................................... 3-5 3-3 Evaluation of Buffer Zones as a Solution to Increased Regulatory Constraints in the Colusa Subreach................................................................................................................................................. 3-7 3-4 Evaluation of Delisting the Valley Elderberry Longhorn Beetle as a Solution to Increased Regulatory Constraints in the Colusa Subreach..................................................................................... 3-8 3-5 Evaluation of Good Neighbor Policy as a Solution to Increased Regulatory Constraints in the Colusa Subreach................................................................................................................................... 3-10 3-6 Evaluation of an HCP as a Solution to Increased Regulatory Constraints in the Colusa Subreach..... 3-12 3-7 Evaluation of MOA/MOUs as a Solution to Increased Regulatory Constraints in the Colusa Subreach............................................................................................................................................... 3-14 3-8 Evaluation of PSHAs under Various Scenarios as a Solution to Increased Regulatory Constraints in the Colusa Subreach ..................................................................................................... 3-16 3-9 Evaluation and Comparison of Solutions to Increased Regulatory Constraints in the Colusa Subreach............................................................................................................................................... 3-18 4-1 Crops Grown in the Colusa Subreach: Priority for Analysis ................................................................. 4-1 4-2 Potential Pest Effects on Agriculture in the Colusa Subreach ............................................................... 4-2 4-3 Host Plant Associations of Pest Insects in the Study Area................................................................... 4-11 4-4 Potential Effects of Restoration on Agricultural Pest Populations....................................................... 4-29 4-5 Summary of Potential Pest Effect Changes on Agriculture Following Riparian Restoration.............. 4-38 5-1 Overall Evaluations of Various Solutions to Increased Pest Damage in the Colusa Subreach.............. 5-8 EDAW Colusa Subreach Planning Table of Contents ii The Nature Conservancy EXHIBITS 1-1 Proposed Habitat Restoration Tracts ..................................................................................................... 1-3 1-2 Land Use in the Colusa Subreach .......................................................................................................... 1-4 1-3 Princeton Southeast (Womble tract) and Jensen Restoration Area Boundary Types ...........................