SOUTHERN COASTAL SANTA BARBARA CREEKS AND ESTUARIES BIOASSESSMENT PROGRAM

Transcription

1 SOUTHERN COASTAL SANTA BARBARA CREEKS AND ESTUARIES BIOASSESSMENT PROGRAM 2013 REPORT Prepared for: City of Santa Barbara, Creeks Division County of Santa Barbara, Project Clean Water Prepared By:

2 Executive Summary Introduction This report summarizes the results of the 2013 Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program, an effort funded by the City of Santa Barbara and County of Santa Barbara. The purpose of the Program is to assess and monitor the biological integrity of creeks and estuaries in the study area as they respond through time to natural and human influences. Ecology Consultants, Inc. (Ecology) prepared the report, and serves as the City s and County s consultant for the Program. This is the 14 th year of the Program, which began in The Program involves annual collection and analysis of benthic macroinvertebrate (BMI) samples and other pertinent physiochemical and biological data in 15 to 20 creek study reaches using U.S. Environmental Protection Agency (USEPA) endorsed rapid bioassessment techniques. BMI samples are analyzed in the laboratory to determine BMI abundance, composition, and diversity. Scores and classifications of biological integrity are determined for study streams using the Index of Biological Integrity (IBI) developed for study area creeks in The IBI yields a numeric score and classifies the biological integrity of a stream as Very Poor, Poor, Fair, Good, or Excellent based on the BMI community present in the stream. Seven core BMI metrics are calculated and used to determine the IBI score. Each core metric is highly sensitive to human disturbance, and collectively they represent different aspects of the BMI community including diversity, composition, and trophic group representation. By condensing complex biological data into an easily understood score and classification of biological integrity, the IBI serves as an effective tool for the City and County in monitoring the condition of local creeks, and evaluating the benefits or consequences of watershed management actions. In 2011 the Program was expanded to include the estuaries of three local watersheds. Estuaries are open water bodies where a freshwater stream meets and mixes with saltwater from the ocean, creating brackish water conditions with salinities that change throughout the year depending on varying seasonal inputs from the stream and ocean tides. USEPA endorsed rapid bioassessment techniques for estuaries were used to collect BMI samples and other pertinent physiochemical and biological data. 6 estuaries were studied this year, as in The IBI cannot be used to assess the condition of local estuaries, which have very different physiochemical conditions (e.g., brackish water, substrate, water flow, etc.) and biological assemblages than do freshwater creeks. It is hoped that an IBI or similar tool to assess the condition of local estuaries can be developed in the future. Study Area The study area encompasses approximately 80 km of the southern Santa Barbara County coast from the Rincon Creek watershed at the Santa Barbara/Ventura County line west to Jalama Creek, which is just north of Point Conception. There are approximately 50 1 st to 5 th order coastal streams along this stretch of coast, all of which drain the southern face of the Santa Ynez Mountains. 52 different stream study reaches in 20 watersheds have been surveyed on one or more occasions from 2000 to stream study reaches were surveyed this year, and 6 estuaries were surveyed. Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 2

3 Methods Physiochemical and biological data for the study creeks and estuaries was gathered through a combination of methods including field surveys, laboratory analyses, spatial data analyses using geographic information system software, and review of United States Geological Survey (USGS) 7.5-minute quadrangle maps and recent aerial photographs. Core metrics were calculated and IBI scores and classifications of biological integrity were determined for the creek study reaches. A suite of BMI metrics was calculated for study estuaries, and evaluated for differences along disturbance and salinity gradients. Results Over the past 14 years, bioassessment data collected through the Program has provided a wealth of information regarding the physiochemical habitat conditions and biota (particularly the BMI community) present in local streams. The influences of natural physiochemical and climatic variability and human development on local stream communities have been extensively examined. The following general statements can be made based on the research completed thus far: Major episodic disturbances including extreme stream flows, drought conditions, and wildfires have been definitively shown to negatively impact stream communities, as evidenced by significantly lower IBI scores and loss or significant reduction of sensitive BMI and vertebrate taxa following such events. Local stream communities have proven to be resilient, typically showing dramatic recovery from extreme episodic disturbances in a year or two. However, some of the more sensitive species (e.g., rainbow trout) have yet to return to streams impacted by recent wildfires, and may require many years to fully recover. Negative impacts of human land use on local stream communities (particularly BMIs) have been documented with highly significant statistical test results. Degradation of stream communities (e.g., lower IBI scores and loss of sensitive species), as well as physiochemical habitat conditions, has increased linearly with increased watershed development, and urban development has been shown to have greater impacts on stream communities and habitat conditions than has agricultural development. Stream habitat restoration sites have shown improved habitat conditions, and in some cases slight improvements in the BMI community over time following restorative actions. Major improvements in stream community condition would likely require larger-scale, watershed-based restorative actions. Over the past three years, a relatively limited data set has been compiled for local estuaries. Study sites have included the range available along a disturbance gradient, from reference sites that are fairly intact in form with little urbanization in their watersheds to disturbed sites that have been substantially altered in form and drain highly urbanized watersheds. Compared with streams, there appears to be less difference in BMI metrics between reference and disturbed estuaries. However, several BMI metrics, most of which are indices of sensitive and/or tolerant taxa, look promising as biological indicator metrics. More surveys are needed to further test, validate, and refine potential indicator metrics. Establishing 4 to 6 reliable indicator metrics will be the basis for developing a reliable IBI for local estuaries. Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 3

4 TABLE OF CONTENTS Page I. INTRODUCTION... 5 II. STUDY AREA... 7 III. METHODS A. Field Surveys B. Laboratory Analysis C. GIS Analyses D. Review of Topographic Maps and Aerial Photographs E. Study Reach Grouping F. Calculation of Core Metrics G. Core Metric Scoring Ranges H. IBI Classifications of Biological Integrity and Scoring Ranges I. BMI Community Metrics for Estuaries IV. RESULTS AND DISCUSSION A. Physiochemical and Biological Data B. IBI Scores and Classifications C. Rainfall and Peak Streamflow Effects on Creeks D. Estuaries V. CLOSING VI. REFERENCES APPENDIX: DATA TABLES FIGURES Page Figure 1 Study Area... 8 Figure 2 Gaviota Coast Study Reaches... 9 Figure 3 Santa Barbara and Goleta Area Study Reaches Figure 4 Carpinteria Area Study Reaches Figure 5 IBI Score by Year for 9 Study Reaches, Figure 6 Selected BMI Parameter Means by Disturbance Class, 2012 and 2013 Estuaries (n=12) Figure 7 Mean %BAIM and %COCO by Disturbance and Salinity TABLES Page Table 1 Study Reaches... 7 Table 2 Core Metric Scoring Ranges Table 3 Classifications of Biological Integrity and Scoring Ranges Table 4 Rainfall/Streamflow Data and Mean Physiochemical/BMI Parameter Values for 9 Study Reaches, Wet vs. Dry Years Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 4

5 I. Introduction This report summarizes the results of the 2013 Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program, an effort funded by the City of Santa Barbara and County of Santa Barbara. This is the 14 th year of the Program, which began in Ecology Consultants, Inc. (Ecology) prepared this report, and serves as the City and County s consultant for the Program. The purpose of the Program is to assess and monitor the biological integrity of study creeks and estuaries as they respond through time to natural and human influences. Karr and Dudley (1981) defined biological integrity as the ability to support and maintain a balanced, integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of natural habitat of the region. (Miller et al., 1988). Bioassessment is the science of assessing the biological integrity of aquatic ecosystems by evaluating the biological assemblages (e.g., benthic macroinvertebrates, fish, amphibians, vegetation, etc.) that inhabit them. Because different taxa (i.e., species, genera, families, etc.) have varying habitat requirements and abilities to withstand water pollution and other forms of habitat disturbance, the presence or absence of particular taxa can serve as an indicator of the overall biological integrity a particular water body. On a broader level, measurements of the biological community relating to abundance, diversity, and trophic structure have proven to be reliable indicators of biological integrity in water bodies (Rosenberg and Resh, 1993, Barbour et al., 1999). The Program involves annual collection and analysis of benthic macroinvertebrate (BMI) samples and other pertinent physiochemical and biological data in stream study reaches using U.S. Environmental Protection Agency (USEPA) endorsed rapid bioassessment methodology. Our sampling methodology has been consistent since 2000, and is very similar to that currently used for the California Surface Water Ambient Monitoring Program (SWAMP), the methods of which have varied over the years. BMI samples are analyzed in the laboratory to determine BMI abundance, composition, and diversity. Scores and classifications of biological integrity are determined for study streams using the BMI based Index of Biological Integrity (IBI) that was developed for study area streams in 2004, and updated in The IBI yields a numeric score and classifies the biological integrity of a given stream as Very Poor, Poor, Fair, Good, or Excellent based on the contents of the BMI sample collected from the stream. Seven core metrics are calculated and used to determine the IBI score. Each core metric is highly sensitive to human disturbance as determined through rigorous statistical analyses of data from local streams, and collectively they represent different aspects of BMI community structure including diversity, composition, and trophic group representation. The data set used to develop the IBI is robust, consisting of 10 years of surveys from a total of 190 stream sites that collectively are influenced by wide differences in physiochemical conditions and types and intensities of human disturbance. By condensing complex biological data into an easily understood score and classification of biological integrity, the IBI serves as an effective tool for the City and County in monitoring the condition of local creeks, and evaluating the benefits or consequences of watershed management actions. More discussion of the IBI and its development is provided in Southern Coastal Santa Barbara County Creeks Bioassessment Program, 2009 Report and Updated Index of Biological Integrity (Ecology Consultants, Inc., 2010). Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 5

6 In 2011 the Program was expanded to include local estuaries. Estuaries are open water bodies where a freshwater stream meets and mixes with saltwater from the ocean, creating brackish water conditions with salinities that change throughout the year depending on varying seasonal inputs from the stream and ocean. USEPA endorsed rapid bioassessment methods for estuaries were used to collect BMI samples and other pertinent physiochemical and biological data. Over the past three years, a relatively limited data set has been compiled for local estuaries. Study sites have included the range available along a disturbance gradient, from reference sites that are fairly intact in form with little urbanization in their watersheds to disturbed sites that have been substantially altered in form and drain highly urbanized watersheds. As with last year, 6 estuaries were studied this year, including 3 disturbed and 3 reference estuaries. The goal for last year was to compare the 3 disturbed estuaries to the 3 reference estuaries, and see whether there were notable differences in the BMI community and other biological parameters. BMI metrics with notable differences between these two groups of estuaries could have promise as core metrics for an estuarine IBI. Last year s results indicate that there is generally less difference in BMI metrics between reference and disturbed estuaries compared to reference and disturbed creeks. Nonetheless, based on the limited data collected so far, several BMI metrics showed promise as ecological indicators in the estuaries, in particular two sensitivity/tolerance metrics that were developed in this study. This year s effort provides additional data needed to further test, validate, and refine potential indicator metrics. Establishing 4 to 6 reliable indicator metrics will be the basis for developing a reliable IBI for local estuaries, which, at the current rate of study, is expected to take several years to accomplish. Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 6

7 II. Study Area The study area encompasses approximately 80 km of the southern Santa Barbara County coast from the Rincon Creek watershed at the Santa Barbara/Ventura County line west to Jalama Creek, which is just north of Point Conception (see Figure 1). There are approximately 50 1 st to 5 th order coastal streams along this stretch of coast, all of which drain the southern face of the Santa Ynez Mountains. 52 different stream study reaches in 20 watersheds have been surveyed on one or more occasions from during the 14 years of the Program. 15 stream and 6 estuarine study reaches were surveyed this year. Table 1 lists this year s study reaches and their locations. Figure 1 shows an overall map of the study area, and Figures 2, 3, and 4 provide more detailed maps and show the locations of the study reaches that have been surveyed over the years (except the Jalama Creek estuary). Table 1: Study Reaches Study Reach Location Creek Study Reaches C1 Carpinteria Creek, 0.25 mi. downstream of Carpinteria Ave. C3 Gobernador Creek, approx mi. upstream of County detention basin SY1 Sycamore Creek just below Mason St. bridge SY3 Sycamore Creek 300m below Highway 192 crossing and Coyote/Sycamore confluence M1 Mission Creek at De la Guerra St. M2 Old Mission Creek at Bohnet Park M3 Mission Creek at upstream end of Rocky Nook Park M4 Rattlesnake Creek, approx. 0.5 mi. upstream of Las Canovas Rd. crossing AB1 Arroyo Burro at upstream end of Alan Rd. AB3 San Roque Creek, 0.25 mi. upstream of Foothill Rd. AB5 Mesa Creek at entrance to Arroyo Burro estuary SA2 San Antonio Creek just upstream of Highway 154 crossing SJ2 San Jose Creek, approx mi. upstream of Patterson Rd. crossing AH1 Arroyo Hondo, approx. 1 mi. upstream of U.S GAV1 Gaviota Creek at State Beach/Park, just below access rd./us 101 junction Estuary Study Reaches SYe Sycamore Creek estuary Me Mission Creek estuary ABe Arroyo Burro estuary Te Tecolote Creek estuary GAVe Gaviota Creek estuary Je Jalama Creek estuary Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 7

8 FIGURE 1: STUDY AREA Study Area N Source: Delorme Topoquads Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 8

9 FIGURE 2: GAVIOTA COAST STUDY REACHES N GAV2 Gaviota Creek GAV1 GAVe SO2 San SO2 Onofre Creek San Onofre Creek SO1 AH1 AH2 Arroyo Hondo Arroyo Hondo Creek R0 R2 R1 Refugio Creek R2 Refugio Creek R1 El Capitan Creek EC1 EC1 Scale: 1 centimeter = 1 kilometer Source: Delorme Topoquads (1999) Study creeks emphasized for ease of recognition Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 9

10 FIGURE 3: SANTA BARBARA AND GOLETA AREA STUDY REACHES Dos Pueblos Creek DP1 N Te Tecolote Creek T2 T3 T1 San Jose Creek SJ2 SJ1 SJ4 SJ3 AT1 Scale: 1 centimeter = 1.5 kilometers Source: Delorme Topoquads (1999) Maria Ygnacio Creek MY3 San Antonio Creek MY2 M6 SA2 MY1 AB3 M4 SA1 M3 Atascadero AB6 AB4 Creek Mission AB7 Creek Arroyo AT2 Burro AB2 M2 M1 AB1 AB5 ABe M5 SY2 SY3 Sycamore Creek Me SY1 SYe Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 10

11 FIGURE 4: CARPINTERIA AREA STUDY REACHES Arroyo Paredon Creek Santa Monica Creek Franklin C3 Rincon AP1 Creek Carpinteria Creek F1 Creek RIN1 SM1 C2 C1 RIN0 N Scale: 1 centimeter = 2 kilometers Source: Delorme Topoquads (1999) Study streams emphasized for ease of recognition Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 11

12 III. Methods Physiochemical and biological data for the creek and estuary study reaches was gathered through a combination of methods including field surveys, laboratory analyses, spatial data analyses using geographic information system (GIS) software, and review of United States Geological Survey (USGS) 7.5-minute quadrangle maps and recent aerial photographs. Biological parameters including core metrics and IBI scores (i.e., for creek study reaches) were calculated using the data. Further discussion of methods is provided below. A. Field Surveys 1. Creeks As in previous years of the Program, field surveys were conducted in the spring during base stream flow conditions (i.e., low flows). The sampling was conducted in May by Ecology, City of Santa Barbara, and County of Santa Barbara staff. Sampling in the spring during base flow conditions provides consistency in the sampling from year to year, as the local stream biota is known to undergo seasonal succession (Cooper et al., 1986). The following was completed during each field survey: General observations were recorded on a standardized field data sheet, including location, date, time, weather, stream flow conditions, water clarity, and human impacts. A 100-meter study reach was delineated along the stream. Stream habitat units (i.e., riffles, runs, pools, etc.) within the study reach were mapped and quantified as a percentage of the total reach length. Stream widths (wetted perimeter and channel bottom) were measured at three transects in the study reach. The three transects were established at the 25, 50 and 75 meter marks in the study reach. Wetted perimeter width is defined as the cross-sectional distance of streambed that is inundated with surface water. Channel bottom width is defined as the cross-sectional distance between the bottoms of the stream banks. Riparian canopy cover was estimated in the center of the stream channel at the three transects using a spherical densitometer. Plant and wildlife species observed in the creek and riparian zone were noted and recorded. Water temperature, conductance, ph, and dissolved oxygen concentration were measured in the field using YSI and Oakton handheld meters. Two measurements of each parameter were made, one in a riffle and the other in a pool, and the two values were averaged. One composite BMI sample was collected from each study reach using a standardized method based on the multi-habitat approach described in the USEPA s Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers (Barbour et al., 1999). Each sample represents approximately one square meter of stream bottom, collected from 10 individual, 0.1-square meter locations (approximately 30 centimeters square). The 10 locations that constituted the sample were selected based on the relative area each stream habitat (i.e., riffles, pools, falls, etc.) covered in the section of stream sampled. For example, if a stream reach contained approximately 50 percent riffles and 50 percent pools, Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 12

13 five locations in riffles and five in pools were selected and sampled. Samples were collected using a D-frame net with 500 µm mesh. In locations with flowing water (e.g., riffles and runs), the net was held upright against the stream bottom, and substrata immediately upstream within the 0.1-square meter area was scraped and stirred up for approximately 15 seconds using feet and hands. Dislodged BMIs and stream bottom materials were carried into the net by the stream current. In areas with little or no current (e.g., pools), stream bottom material was stirred up by foot, followed by a quick sweep of the net through the water column to capture dislodged BMIs. This was repeated three times in each pool sampling location. After each BMI sample was collected, it was rinsed with water in a 500 µm sieve to wash out fine sediments, transferred to a plastic container, and preserved in 70 percent ethanol. A semi-quantitative stream habitat assessment was conducted using the protocol provided in the USEPA s Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers. Per this protocol, habitat components were visually assessed and scored, including stream substrate/cover, sediment embeddedness, stream velocity/depth regime, sediment deposition, channel flow status, human alteration, channel sinuosity, habitat complexity/variability, bank stability, vegetative protection, and width and composition of riparian vegetation. Each study reach was assigned a total score of between zero and 200 based on the sum of scores assigned to each habitat component. Criteria from the USEPA protocol were used to guide the scoring. Quality control measures were incorporated into the field surveys to insure accurate and consistent data gathering. Water monitoring equipment was calibrated regularly. Field crew members were trained to properly operate equipment, take measurements, collect BMI samples, and conduct stream habitat assessments. Stream habitat assessments were completed by the field crew as a group. 2. Estuaries Ecology conducted a rapid bioassessment survey in each study estuary in early October. Methodology was based on the Tier 1 approach described in Estuarine and Coastal Marine Waters: Bioassessment and Biocriteria Technical Guidance (Bowman et al., 2000). The Tier 1 approach is intended to provide an assessment of coastal wetland habitats based on sampling of one or more biological assemblages (e.g., algae, invertebrates, fish, etc.) and collecting data on water chemistry and bottom characteristics. The following was completed: General observations were recorded, including study reach location, date, time, weather, water clarity, sediment composition, vegetation, hydrologic condition (i.e., estuary open or closed to ocean), and sources of human disturbance. Measurements of water temperature, ph, dissolved oxygen concentration, conductance, and salinity were made. When feasible, measurements were made at 2 monitoring stations in the estuary: one nearest the ocean (i.e., the mouth), and one in the upper (i.e., upstream) portion of the estuary. Measurement sites were spread throughout the estuary to determine if a longitudinal (i.e., downstream to upstream) gradient in salinity or temperature existed due to differential influences of saltwater and freshwater inputs. In some cases (e.g., Sycamore Creek and Jalama estuaries), the upstream portion of the estuary was inaccessible, thus water chemistry measurements were taken at the downstream end only. Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 13

14 BMI samples were collected at the upstream and downstream monitoring stations where feasible. When the upstream end of the estuary was inaccessible, samples were collected from the downstream end only. Two separate samples were collected at each monitoring station; (1) an infaunal sample consisting of approximately the top 6 inches of sediments from two approximately 10 cm diameter areas of the estuary bottom collected in 1 to 2 feet of water using a core sampler, and (2) an epibenthic sample consisting of material collected in five sweeps with a D-net similar to the pool sampling method for streams. After collection, each sample was drained through a 0.5-millimeter mesh sieve to wash out fine sediments, and the remaining material was placed into a plastic bottle filled with 70% ethanol solution for preservation. In total, approximately 0.5m 2 of bottom area was sampled at each monitoring station. Quality control measures were incorporated into the field surveys to insure accurate and consistent data gathering. Water monitoring equipment was calibrated regularly. Field crew members were trained to properly operate equipment, take measurements, and collect BMI samples. B. Laboratory Analyses BMI samples were processed in the laboratory to determine BMI community composition (i.e., taxa present and relative abundance) and overall density. Each BMI sample was strained through a 500-µm mesh sieve and washed with water to remove ethanol and fine sediments. The sample was placed in a plastic tray marked with equally-sized squares in a grid pattern. The entire sample was spread out evenly across the squares. Squares of material were randomly selected, and sorted one at a time under a dissecting microscope (7X to 50X magnification) until the targeted number of BMIs were located and picked out. The proportion of the sample sorted was noted. For creeks, 330 BMIs were picked from each sample. 300 of the 330 BMIs picked from each sample were randomly selected for identification. A target of 300 BMIs was set for each estuary. The infaunal sample was sorted through first, and up to 150 BMIs were picked and identified. Next, the epibenthic sample was sorted, and the remaining number of BMIs were picked and identified to reach the target of 300. When samples were collected at both upstream and downstream stations in the estuary, 150 BMIs were picked from each station, starting with up to 75 from the infaunal sample, and the remainder from the epibenthic sample. BMIs were identified using standard taxonomic keys. Insect taxa were identified to the family level. Non-insect taxa (e.g., oligochaetes, crustaceans, etc.) were typically identified to order or class. After processing and identification, sorted BMIs were bottled in 70 percent ethanol for storage. Quality control measures were incorporated into the laboratory analyses to ensure random selection and accurate enumeration and identification of BMIs. BMI sample processing methods were clearly established and strictly followed. C. GIS Analyses GIS Arcview software was used to calculate upstream watershed area and watershed land use covers for each study reach. Watershed areas were calculated based on watershed boundaries generated in Arcview. Watershed land uses and percent cover for each study reach were calculated by superimposing watershed boundaries over a digital land cover GIS layer for the region. The land cover layer was produced the California Department of Forestry and Fire Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 14

15 Protection s (CDF) Fire and Resource Assessment Program (FRAP). The CDF land use map for the region showed coverage by the following eight land use categories: urban, agriculture, herbaceous, hardwood, shrub, conifer, water, and barren/other. Recent aerial photographs (2013) of the region available on Google Earth were reviewed to check the accuracy of the GIS land use layer. The GIS and aerial photograph land use maps were in close agreement, and only minor adjustments to the GIS-based calculations were necessary. The parameter percent watershed disturbed was calculated for each study reach by using the following equation: Percent watershed disturbed = % urban + % agriculture + 0.5(% herbaceous) Herbaceous areas were counted as partially (i.e., half) disturbed to reflect that much of the herbaceous lands in this region are used for livestock grazing or are previously cleared land. D. Review of Topographic Maps USGS 7.5-minute quadrangle topographic maps (1:24,000 scale) for the study area were reviewed to determine stream order, elevation, and gradient for each study reach. Gradient was determined by dividing the elevation change between topographic contours immediately upstream and downstream of the study reach by the stream length between the contours. Stream length was determined by tracing a map wheel over the stream path. E. Study Reach Grouping 1. Creeks Creek study reaches are placed into three different groups based on their level of human disturbance. These disturbance groups are assigned to study reaches a priori (i.e., before the analyses of biological data) based on physical habitat assessment scores and percent watershed disturbed. The following criteria are used to group study reaches: REF = Reference stream reaches are minimally disturbed by human activities. Habitat assessment score is 150/200 or greater, and 5 percent or less of the upstream watershed is disturbed. MOD DIST = Stream reaches are lightly to moderately disturbed by human activities. Habitat assessment score is between 120 and 149. This category also includes stream reaches with a habitat assessment score of 150 or greater, but with greater than 5 percent of the upstream watershed disturbed. HIGH DIST= Stream reaches that are heavily disturbed by human activities including agricultural and urban/suburban land uses. Habitat assessment score is less than Estuaries Estuary study reaches were also placed into three different groups based on their level of human disturbance. These disturbance groups were assigned to study reaches a priori (i.e., before the analyses of biological data) based on upstream watershed land use patterns and habitat conditions at the estuary itself. The following criteria were used to group the study reaches: Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 15

16 REF = Estuaries that are in a reference condition, or lightly disturbed by human activities. 10 percent or less of their watershed area is developed with urban or agricultural uses. Impacts to estuary form and vegetative buffer are minor to moderate. Local impacts can include dredging and filling operations, breaching berms at the ocean outlet, vegetation removal, beach grooming, sedimentation, and traffic from people and their pets (noise, lighting, trampling, etc.) MOD DIST = Estuaries that are moderately disturbed by human activities. 10 to 25 percent of their watershed area is developed with urban or agricultural uses. Impacts to estuary form and vegetative buffer are minor to moderate. HIGH DIST= Estuaries that are highly disturbed by human activities. Greater than 25 percent of their watershed area is developed with urban or agricultural uses. Impacts to estuary form and vegetative buffer are moderate to high. F. Calculation of Core Metrics for Creeks The 7 core metrics were calculated for each stream study reach for use in determining IBI scores and classifications of biological integrity. The core metrics are among the most sensitive to human disturbance as determined by rigorous statistical analyses (Ecology Consultants, Inc., 2010). Collectively, the core metrics are diversified in that they represent different aspects of community structure including diversity, disturbance sensitivity, and trophic structure. Each core metric and its method of calculation are discussed below. Number of Insect Families was determined by summing the number of insect families found in the sample. Number of EPT Families was determined by summing the number of families found in the sample from the insect orders Ephemeroptera (mayflies), Plecoptera (stoneflies), and Tricoptera (caddisflies), which as a group are generally sensitive to human disturbance. Percent EPT minus Baetidae was determined by summing individuals from the insect orders Ephemeroptera (except Baetidae), Plecoptera, and Tricoptera, dividing by the total number of BMIs in the sample, and multiplying by 100. Percent PT was determined by summing individuals from the insect orders Plecoptera and Tricoptera, dividing by the total number of BMIs in the sample, and multiplying by 100. Tolerance value average and percent sensitive BMIs were calculated using disturbance tolerance values for individual BMI taxa of between 0 and 10 based on their ability to withstand human disturbance. A tolerance value of 0 indicates that a BMI is extremely intolerant of human disturbance, with increasing scores indicating greater tolerances to human disturbance. Tolerance value average was determined by summing the tolerance values of all the individual BMIs in the sample, and dividing by the total number of BMIs in the sample. Percent sensitive BMIs was determined by summing the individuals with a tolerance value of 3 or less, dividing by the total number of BMIs in the sample, and multiplying by 100. Tolerance values and sensitivity designations for individual BMI taxa are provided in Table A-1 of Appendix A. Tolerance values have been assigned to most of the BMI taxa found in the study area based on statistical analyses of BMI data collected in study area streams from 2000 Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 16

17 to These analyses evaluated abundance data for each taxa along a disturbance gradient. Tolerance values from List of Californian Macroinvertebrate Taxa and Standard Taxonomic Effort (California Department of Fish and Game, 2002) were used for taxa that did not occur in sufficient abundance in local streams to allow for meaningful statistical analyses. 8 taxa that occur in the study area did not meet abundance criteria established in the 2009 study, nor did they have tolerance values in List of Californian Macroinvertebrate Taxa and Standard Taxonomic Effort. Thus, no tolerance values are provided for these taxa. For further details, see the 2009 report (Ecology, 2010). Percent predators + shredders was determined by summing individual BMIs with a predator or shedder functional feeding group designation, dividing by the total number of BMIs in the sample, and multiplying by 100. Functional feeding group designations were obtained from An Introduction to the Aquatic Insects of North America (Merritt and Cummins, 1996). G. Core Metric Scoring Ranges for Creeks The IBI sets scoring ranges of between 0 and 10 for each of the seven core metrics (see Table 2). See the 2009 Report for detailed discussion of how core metric scoring ranges were determined. Table 2: Core Metric Scoring Ranges Score # insect families # EPT families % EPT- Baetidae % PT Tolerance value avg. % sensitive BMIs %shredders +predators or less to to to to to to to to to to to to to to to to to 26 8 to to to to to to 22 6 to to to to to 18 7 to 8 13 to 17 4 to to to 19 8 to to 15 5 to 6 8 to to to 13 6 to to 12 3 to 4 2 to to to 7 4 to to 10 1 to to to to 6 0 to to 1 For core metrics that decrease with increasing human disturbance (e.g., # insect families), higher values corresponded with higher scores. For core metrics that increase with increasing human disturbance (e.g., tolerance value average), lower values corresponded with higher scores. H. IBI Classifications of Biological Integrity and Scoring Ranges for Creeks Individual scores for the seven core metrics are summed to provide a total score of between 0 and 70 for the study reach. The IBI provides 5 classifications of biological integrity based on the total score: Excellent, Good, Fair, Poor, and Very Poor. IBI classifications and scoring ranges are provided in Table 3. See the 2009 report for detailed discussion of how ranges were set for the 5 classifications of biological integrity. Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 17

18 Table 3 Classifications of Biological Integrity and Scoring Ranges (Creeks) Category Scoring Range Excellent 61 to 70 Good 48 to 60 Fair 31 to 47 Poor 9 to 30 Very Poor 0 to 8 I. BMI Community Metrics for Estuaries 17 BMI community metrics were calculated for the study estuaries, including measures of abundance, diversity, disturbance sensitivity, and trophic structure. Many of the metrics calculated have been used effectively as indicators of ecological condition in one or more recent estuarine studies conducted throughout the nation. Table A-4 in the Appendix lists these metrics. IV. Results and Discussion A. Physiochemical and Biological Data Table A-1 in the Appendix provides physiochemical data collected at the creek study reaches this year. Table A-1 also lists BMI taxa and abundances for each creek study reach, as well as BMI density, core metric values, and IBI score. Tolerance values and functional feeding groups are provided for individual BMI taxa. Table A-2 provides a list of the plant species observed at each creek study reach, and the number and percentage of native vs. introduced plant species observed. Table A-3 provides a list of vertebrate species observed at the creek study reaches. For study reaches that have been surveyed multiple times, plant and vertebrate species observations are combined. Table A-4 provides physiochemical and BMI data and metrics for the study estuaries. B. IBI Scores and Classifications (Creeks) Table A-5 lists core metric values, IBI scores, and classifications of biological integrity for the study reaches in Table A-5 also provides the range of IBI scores and classifications of biological integrity for the study reaches in all years of study. The following discusses IBI scores at the individual study reaches for 2013, and compares this year s scores to previous years. Physical habitat conditions and other factors that have likely affected the creek biota are also discussed. 1. City of Santa Barbara Study Creeks Sycamore Creek Drought conditions the past two years caused decreased stream width, depth, and flow in Sycamore Creek this year. For the first time in 11 years of studying SY1, dry conditions were Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 18

19 observed during the spring surveys. The upper half of the study reach was dry, while in the downstream half of the study reach pools were present and riffles were reduced to a narrow slow trickle. Stream flow was very low but continuous at SY3. Stream width and depth were relatively low at both study reaches compared to most years. Water chemistry measurements at SY1 and SY3 were typical of previous years, with low water temperature (16.1 and 16.2 ºC, respectively), optimal dissolved oxygen (7.3 and 8.0 mg/l., respectively), and specific conductance (2,969 and 2,121 µs, respectively). Riparian canopy cover was 98% at SY1 and 95% at SY3, reflective of the mature riparian overstory trees present at both sites. Habitat assessment score at SY1 was 92, reflecting its HIGH DIST designation, while SY3 scored 127, reflecting its MOD DIST designation. Low stream flow had a downward effect on the habitat assessment scores. IBI score at SY1 was 24 (Poor), which is similar to the last two years, and the highest score recorded in 11 years of study. IBI score at SY3 was 31 (Fair) this year (2013), which is the highest score recorded in 8 years of study, and the first time SY3 has scored above the Poor range. The primary reason for the relative improvement in IBI scores at SY1 and SY3 was a higher proportion of shredder/predator and sensitive taxa (e.g., Tricoptera). Mission Creek Stream width, depth, and flow were relatively low at M3 and M4 due to the drought conditions. Flow in riffles was reduced to a trickle, but flow was continuous in both study reaches. Water chemistry measurements at M3 and M4 were typical of previous years, with low water temperature (15.6 and 15.4 ºC, respectively), good to optimal dissolved oxygen (6.3 and 9.0 mg/l., respectively), and low specific conductance (1,209 and 976 µs, respectively). Riparian canopy cover was 95% at M3 and 93% at M4, reflective of the mature riparian overstory trees present at both sites. Habitat assessment scores were lower than normal at these study reaches (148 at M3 and 165 at M4) due to lower than normal stream flow. IBI score at M3 was 29 (Poor), which is the third lowest in 13 years of study. M3 typically scores Fair or Good, and has been as high as the Excellent range. This study reach has been known to go dry in the summer/fall months in drought years. This is a probable cause of the lower IBI score this year, as the stream would be in a state of recovery following a dry period. IBI score at M4 was 48 this year, or the bottom of the Good range. M4 typically scores in the Good to Excellent range. There was a higher than normal proportion of Chironomids and noninsect taxa, which has been a typical trend in drought years and can cause a downward trend on IBI score at sites that typically score in the Good to Excellent range. California newts (Taricha torosa) were observed at M4 this year, but not at M3. Rainbow trout (Oncorhynchus mykiss) were not observed at M3 or M4 this year. These vertebrates are considered indicator species and were regularly observed at both study reaches prior to the Jesusita Fire in May Stream flow in M1 and M2 was low, but higher than in the upstream study reaches (M3 and M4). Return flows from urban uses are a significant contributor to overall stream flow at M1 and M2. Water chemistry measurements at M1 and M2 were typical of previous years, with moderate to high water temperature (23.3 and 18.5 ºC, respectively), good to optimal dissolved oxygen (9.0 and 9.5 mg/l., respectively), and moderate specific conductance (1,471 and 1,454 µs, respectively). Riparian canopy cover was 67% at M1, which contributes to higher stream Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 19

20 temperature, and 95% at M2. Habitat assessment score was low at M1 (93) similarly to previous years, and indicative of its HIGH DIST condition. M2 scored slightly better (111), mostly due to the maturing riparian vegetation that has been restored at the site. IBI score at M1 was 3 (Very Poor) this year. IBI score has been in the Very Poor or lower Poor range at this study reach in all 13 years of study. M2 had an IBI score of 14 (Poor) this year. IBI score has ranged from 5 to 14 at M2 in 10 years of study. Arroyo Burro Since the Jesusita Fire burned approximately 70 percent of its upstream watershed in May 2009, there has been notable improvement in habitat conditions at AB3, with less fine sediment, deeper pools, and more exposed hard substrate. The riparian canopy, which was burned out by the fire, is still largely open, and it will likely take several years for it to recover fully. There has, however, been considerable regrowth of the understory plants, and some of the larger canopy trees have survived the fire as evidenced by new growth. Riparian canopy cover improved to 77 percent this year. Water temperatures were cooler last year (14.9ºC) and this year (15.4ºC) compared to Drought conditions reduced stream flow at AB3 mostly to standing pools at the time of the spring survey. Riffles were mostly dry, with only a faint trickle present in some areas. The lack of flow caused low dissolved oxygen (3.6 mg/l), and specific conductance was higher than normal (2,240 µs). IBI score at AB3 improved to 33 (Fair) in 2012, its highest score since This year (2013), IBI score dropped to 12 (Poor), or the second lowest score recorded at AB3 in 13 years of study. There was a higher than normal proportion of Chironomids and non-insect taxa at AB3 this year, which has been a typical trend in drought years. Insect and EPT diversity were also low relative to some years, as was the percentage of EPT taxa. The intermittency of stream flow at this site over the years is now thought to be the primary reason for the large variability in IBI scores (11 to 62) observed over the years. AB3 has been observed to go completely dry in the summer in drought years such as 2012 and It is not currently known to what degree upstream water diversions are contributing to the intermittency of flow at this study reach. Downstream study reach AB1 (HIGH DIST) had habitat assessment score (119), water chemistry, and riparian canopy cover (80%) within the ranges from previous years. IBI score was 26 (Poor) this year, the highest score recorded in 11 years of study. AB5 (HIGH DIST), a habitat restoration site along the lower watershed tributary Mesa Creek, was daylighted in 2007 (i.e., it was formerly an underground storm drain). It has a small watershed area, narrow channel bottom (2 to 3 feet wide), and poorly developed substrate that consists mostly of soft muds and bedrock, with some angular gravel and cobble. Planted in 2007, the riparian vegetation at this site has become very dense, with tree heights of more than 25 feet and riparian canopy cover of 100 percent. Stream temperature was cool (16.3 ºC) as in the last few years, and specific conductance was again very high (4,112 µs). Mineral concentrations are presumed to be high naturally in this creek. IBI score was 10 (Poor), compared to 14 in IBI score at AB5 has ranged from 3 to 14 in 7 years of study. Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 20

21 2. County of Santa Barbara Study Creeks Carpinteria Creek C1 had a habitat assessment score of 94 this year. Habitat assessment score has varied widely (88 to 142) at this site in 12 years of study, primarily due to episodic clearing of the stream channel and riparian corridor for flood control purposes. Very low stream flow depressed the score this year. Riparian canopy cover was 75 percent, stream temperature was low (15.8 ºC), and specific conductance was moderately high (1,568 µs) as in most previous years. Dissolved oxygen was good at 6.2 mg/l this year, and has varied from 5.0 to 14.0 mg/l over the years. IBI score at C1 was 3 (Very Poor), and within the range (0 to 11) from 12 years of study. The consistently low IBI scores for C1 over the years are puzzling. While this site is disturbed, it has good substrate dominated by cobble, gravel, and sand, well-defined riffles and pools, natural banks and a decent riparian corridor with numerous mature canopy trees. Stream flow is perennial except in the driest years. The basic water quality parameters measured have shown signs of disturbance in the form of moderately high conductivity and somewhat variable dissolved oxygen, but not alarmingly so. The watershed has little urban use (3 percent), some agriculture (17 percent), and is mostly undisturbed wilderness (80 percent). Other sites such as R0, RIN0, and SJ2 with similar habitat conditions and watershed characteristics have consistently had much higher IBI scores compared to C1. In fact, several sites with greater watershed and local disturbances such as SY1 and AB1 have consistently higher IBI scores than C1. More detailed analyses of the water chemistry at C1 and determination of upstream water pollutant sources may yield greater understanding of the causes of impairment at this site. C3, a lightly impacted reference stream reach in Gobernador Creek (Carpinteria Creek tributary), had lower habitat assessment score (144) compared to previous years, primarily due to low stream flow. Water chemistry measurements were favorable as in previous years, with low temperature (13.0 ºC) and specific conductance (795 µs), and optimal dissolved oxygen (9.0 mg/l). Riparian canopy cover was good at 89 percent, a reflection of the mature riparian canopy present at C3. IBI score (46) was on the high end of the Fair range. IBI scores have typically been in the Good to Excellent range at C3. San Antonio Creek SA2 had a habitat assessment score of 123. Low stream flow had a downward effect on habitat assessment score. While this stream has little development as a total percentage of its watershed (94% undisturbed open space), heavy sedimentation from orchards proximal to SA2 has been a chronic stressor. This year s water chemistry readings were similar to previous years, with low temperature (19.2 ºC), moderate specific conductance (1,623 µs) and adequate dissolved oxygen (7.0 mg/l). Riparian canopy cover was excellent at 93 percent due to the mature riparian canopy present at SA2. IBI score (33) was at the low end of Fair. IBI score at SA2 has ranged from 23 to 62 in 9 years of study. San Jose Creek SJ2 had a habitat assessment score of 110, which was depressed by the low stream flow conditions. Similar to SA2, heavy sedimentation from upstream orchards has been a chronic problem at SJ2. This year, water temperature was low (17.6 ºC) and dissolved oxygen was Southern Coastal Santa Barbara Creeks and Estuaries Bioassessment Program Page 21