GEOLOGICAL SURVEY OF ALABAMA Berry H. (Nick) Tew, Jr. State Geologist ECOSYSTEMS INVESTIGATIONS PROGRAM CALIBRATION OF THE INDEX OF BIOTIC INTEGRITY FOR THE SOUTHERN PLAINS ICHTHYOREGION IN ALABAMA OPEN-FILE REPORT 1210 by Patrick E. O'Neil and Thomas E. Shepard Prepared in cooperation with the Alabama Department of Environmental Management and the Alabama Department of Conservation and Natural Resources Tuscaloosa, Alabama 2012 TABLE OF CONTENTS Abstract ............................................................ 1 Introduction.......................................................... 2 Acknowledgments .................................................... 6 Objectives........................................................... 7 Study area .......................................................... 7 Southern Plains ichthyoregion ...................................... 7 Methods ............................................................ 9 IBI sample collection ............................................. 9 Habitat measures............................................... 11 Habitat metrics ........................................... 12 The human disturbance gradient ................................... 16 IBI metrics and scoring criteria..................................... 20 Designation of guilds....................................... 21 Results and discussion................................................ 23 Sampling sites and collection results . 23 Selection and scoring of Southern Plains IBI metrics . 48 Metrics selected for the Southern Plains IBI . 54 1. Number of native species ................................. 54 2. Number of shiner species ................................ 56 3. Number of sucker species................................. 56 4. Number of centrarchid species ............................. 59 5. Number of darter + madtom species . 59 6. Percent as tolerant species................................ 62 7. Percent as Green Sunfish + Yellow Bullheads . 62 8. Percent as insectivorous cyprinids . 65 9. Percent as top carnivores ................................. 65 10. Percent with DELT+hybrids............................... 67 11. Percent as simple lithophilic spawners . 67 12. Percent as manipulative nonlithophilic spawners . 70 IBI development for the Southern Plains ichthyoregion . 70 Conclusions ........................................................ 83 References cited..................................................... 89 Appendix A. Habitat evaluation forms..................................... 94 Appendix B. Reproduction and trophic guild classifications for Alabama fishes . 97 Appendix C. Southern Plains ichthyoregion fish community sampling data ........................................................ 108 TABLES Table 1. IBI sampling sites in the Southern Plains ichthyoregion, 2004-11 ...................................................... 25 Table 2. Fish species collected in the Southern Plains ichthyoregion, 2004-11 . 30 ii Table 3. Rapid habitat assessment scores for sites in the Southern Plains ichthyoregion .................................................. 39 Table 4. Human disturbance metrics for sites in the Southern Plains ichthyoregion .................................................. 42 Table 5. LDI-weighted human disturbance metrics for sites in the Southern Plains ichthyoregion .................................................. 45 Table 6. Correlation coefficients between candidate IBI metrics and glide-pool habitat assessment metrics ....................................... 49 Table 7. Correlation coefficients between candidate IBI metrics and human disturbance metrics ............................................. 50 Table 8. Statistical and responsive measures for candidate IBI metrics . 51 Table 9. Redundancy analysis for Southern Plains ichthyoregion IBI metrics . 53 Table 10. Fish community values for Southern Plains IBI metrics . 73 Table 11. Scores for Southern Plains IBI metrics . 76 Table 12. IBI integrity classes for Alabama ichthyoregions . 80 FIGURES Figure 1. Preliminary ichthyoregion classification for Alabama . 5 Figure 2. Ecoregions and river systems in Alabama . 8 Figure 3. Conceptual model illustrating the relationship between disturbance, stressor, and response. .......................................... 17 Figure 4. Location of IBI sampling sites in the Southern Plains ichthyoregion . 24 Figure 5. Frequency distribution of sampling sites in the Southern Plains ichthyoregion by watershed area and human disturbance . 29 Figure 6. Relationships between the IBI metric number of native species and watershed area, disturbance, and habitat. 55 Figure 7. Relationships between the IBI metric number of shiner species and watershed area, disturbance, and habitat . 57 Figure 8. Relationships between the IBI metric number of sucker species and watershed area, disturbance, and habitat . 58 Figure 9. Relationships between the IBI metric number of centrarchid species and watershed area, disturbance, and habitat . 60 Figure 10. Relationships between the IBI metric number of darter+madtom species and watershed area, disturbance, and habitat . 61 Figure 11. Relationships between the IBI metric percent tolerant species and watershed area, disturbance, and habitat . 63 Figure 12. Relationships between the IBI metric percent Green Sunfish+Yellow Bullheads and watershed area, disturbance, and habitat . 64 Figure 13. Relationships between the IBI metric percent insectivorous cyprinids and watershed area, disturbance, and habitat . 66 iii Figure 14. Relationships between the IBI metric percent top carnivores and watershed area, disturbance, and habitat. 68 Figure 15. Relationships between the IBI metric percent DELT + hybrids and watershed area, disturbance, and habitat . 69 Figure 16. Relationships between the IBI metric percent simple lithophilic spawners and watershed area, disturbance, and habitat . 71 Figure 17. Relationships between the IBI metric percent manipulative nonlithophilic spawners and watershed area, disturbance, and habitat . 72 Figure 18. Frequency distribution of IBI integrity classes for sites in the Southern Plains ichthyoregion............................................. 80 Figure 19. Comparison of the IBI in level IV ecoregions and drainages relative to habitat quality and a comparison of IBI scores for small and large watersheds relative to habitat quality . 81 Figure 20. Comparison of the IBI in level IV ecoregions and drainages relative to human disturbance and a comparison of IBI scores for small and large watersheds relative to human disturbance . 82 Figure 21. Tiered aquatic life use relationships between the IBI, habitat quality, and human disturbance for sites in the Southern Plains ichthyoregion . 84 Figure 22. Biological condition gradient models for the Southern Plains ichthyoregion .................................................. 85 iv ABSTRACT The Southern Plains ichthyoregion in Alabama was sampled from 2004 through 2011 to develop data for creating and calibrating the Index of Biotic Integrity (IBI). One hundred and three sites were selected to represent a range of watershed areas and levels of human disturbance. Watershed areas at sampled sites ranged from 2.9 mi2 up to 435 mi22, with 47 percent of the watersheds <25 mi , 32 percent ranging from 25 to 100 mi22, and 21 percent >100 mi in area. Rapid habitat assessments were completed for each sample and eight measures of human disturbance were derived for each site from a geographic information system (GIS). Thirty-four candidate IBI metrics were screened for inclusion in the IBI by evaluating their relationship to the habitat assessment and human disturbance metrics. Both human disturbance metrics and habitat metrics were correlated with IBI metrics, but habitat metrics were more predictive of biological metrics and the IBI. Twelve metrics were selected for the Southern Plains IBI: number of native species, number of shiner species, number of sucker species, number of centrarchid species, number of darter+madtom species, percent as tolerant species, percent as Green Sunfish+Yellow Bullheads, percent as insectivorous cyprinids, percent as top carnivores, percent with DELT+hybrids (DELT=deformities, eroded fins, lesions, tumors), percent as simple lithophilic spawners, and percent as manipulative nonlithophilic spawners. Only habitat measures were effective in discriminating sites with good biological condition from sites with poor condition, though the degree varied with the individual IBI metric. Thirty-one percent of the sites scored in the poor to very poor range, 35 percent in the fair range, and 34 percent in the good to excellent range. The range of scores for each integrity class of the Southern Plains IBI were similar to those developed for the Plateau, Hills and Coastal Terraces, Ridge and Valley/Piedmont IBI and slightly higher than criteria developed for the Tennessee Valley IBI. The Southern Plains IBI integrity classes were applied to the USEPA biological condition gradient concept for tiered aquatic life uses to model the response of biological condition to ecosystem stress in the region. This model can be used to better assess stream aquatic life use in Southern Plains streams and provide an additional water quality screening tool for locating and defining use- impaired streams. This report is an update of an earlier version of the Southern Plains 1 ichthyoregion IBI (O’Neil and Shepard, 2009) prepared in the first phases of the statewide IBI project. INTRODUCTION The Geological Survey