Final Report for “Creating and Index of Biological Integrity for Coastal Sage Scrub: A tool for habitat quality assessment and monitoring.” Prepared by: Dr. Jay Diffendorfer1, Genie Fleming2, Jennifer Duggan2, Robert Chapman2 and Dana Hogan2. 12/6/04 1. Illinois Natural History Survey, 607 East Peabody Drive, Champaign, Illinois 61820. [email protected], 217-244-4385 2. San Diego State University, Department of Biology, 5500 Campanile Dr, San Diego, CA, 92182. 1 EXECUTIVE SUMMARY............................................................................................................................4 INTRODUCTION .........................................................................................................................................6 Monitoring in NCCP Reserves. .................................................................................................................7 Methods of assessing ecological condition............................................................................................7 Existing approaches for measuring habitat quality...............................................................................7 Geographic Information Systems (GIS) based approaches to measuring habitat quality.....................9 Index-based indicators of ecological condition........................................................................................10 Step 3. Metric selection and statistical analyses..................................................................................14 Step 4. Validation and verification. .....................................................................................................16 How disturbance is measured in IBIs ..................................................................................................17 IBI methods in Southern California .............................................................................................................19 Spatial Scale of the IBI ............................................................................................................................19 Measuring disturbance .............................................................................................................................20 Methods....................................................................................................................................................21 Study areas...........................................................................................................................................21 Overall sampling effort. .......................................................................................................................22 Grid design and timing. .......................................................................................................................27 Taxa specific sampling.........................................................................................................................28 Data Analysis and IBI development techniques...................................................................................31 RESULTS ....................................................................................................................................................34 Section 1: Overall diversity trends and vegetation relationships.............................................................34 Patterns in species richness across taxa: Do taxa respond similarly to disturbance? .........................34 Patterns between native shrub cover and exotic invasion....................................................................35 Overall taxa response to levels of exotic invasion...............................................................................36 Section 2. Exploratory Data Analyses for responses to increased exotic cover, metric selection and scoring......................................................................................................................................................38 Methodological overview: ...................................................................................................................38 Ants.......................................................................................................................................................39 Arthropods. ..........................................................................................................................................40 Birds.....................................................................................................................................................41 Herpetofauna. ......................................................................................................................................43 Mammals..............................................................................................................................................45 Vegetation. ...........................................................................................................................................47 An IBI for CSS:....................................................................................................................................49 Metric Clustering Methods and results................................................................................................52 Year 1 ...................................................................................................................................................52 Year 2 ...................................................................................................................................................55 Both years ............................................................................................................................................57 ANOVA results on Clusters..................................................................................................................58 Year 1. ..................................................................................................................................................59 Year 2. ..................................................................................................................................................60 Both years. ...........................................................................................................................................60 Summary...............................................................................................................................................61 CONCLUSIONS AND FUTURE WORK. .................................................................................................61 Is an IBI for CSS possible? ......................................................................................................................61 2 Is an IBI for CSS ready for use? ..............................................................................................................63 CSS-IBI Validation...............................................................................................................................63 IBI Refinement......................................................................................................................................64 Is an IBI for CSS necessary?................................................................................................................66 Additional items worth mentioning......................................................................................................69 3 EXECUTIVE SUMMARY This report is the final deliverable for a project between Dr. Jay Diffendorfer and the California Department of Fish and Game (CDF&G) “Creating and Index of Biological Integrity for Coastal Sage Scrub: A tool for habitat quality assessment and monitoring “. The project aimed to develop an Index of Biological Integrity (IBI) for Coastal Sage Scrub (CSS) useful in NCCP monitoring programs. The report contains three main sections and 3 appendices. We first review current methodology for assessing habitat quality, describe how IBI’s are developed, and describe the methods we used to develop an IBI for CSS in the introduction. In the results, we describe the development and testing of the IBI. In the conclusion we speak frankly about the implications of our research, the limitations of the IBI and the role it can play in CSS monitoring programs. The appendices support the main document. Introduction. Currently, habitat quality assessment employs single species approaches such as indicator or umbrella species, GIS-based methods, or multi-metric approaches such as IBIs. Assessing habitat quality over large spatial scales for use in reserve design is typically done by a variety of GIS-based approaches. However, at smaller spatial scales, the reliability of the GIS-based approaches declines. At these smaller spatial scales, multi-metric indices, such as the Index of Biological Integrity have been successfully developed. IBI’s are developed using a four-step process: establishing biological dose-response curves, developing scoring systems, selecting metrics and statistically analyzing the IBI, and IBI validation or verification. In the report, we explain each of these steps in detail giving examples from successful IBIs. Our study focused on steps 1 through 3 because it was not appropriate to include validation in the original contract until we had evidence an IBI was feasible. Measuring disturbance