Caspar Creek Macroinvertebrate Assemblage Responses to Forest Management

Caspar Creek macroinvertebrate assemblage responses to forest management

and hydrologic disturbance

Robert J. Danehy1 and Ivan Arismendi2

1 Catchment Aquatic Ecology, 5335 Saratoga St., Eugene, OR 97405

2 Oregon State University, Department of Fisheries and Wildlife, 104 Nash Hall, Corvallis, OR 97331, USA.

Citation: Danehy, R.J. and I. Arismendi. 2018. Caspar Creek macroinvertebrate assemblage responses to forest management and hydrologic disturbance. Unpublished Report prepared for the California Department of Forestry and Fire Protection, contract # 8CA03674. Sacramento, CA. 18 p.

Title: Caspar Creek macroinvertebrate assemblage responses to forest management and hydrologic disturbance

Danehy1 R.J. and I. Arismendi 2

Abstract: We analyzed data sets from the Caspar Creek Watershed study, with a 55-year comprehensive record of hydrologic regime in two sub-watersheds with different logging treatments, and three separate instream biologic studies conducted since 1990. Long-term data sets of instream biota are rare, and we used them to investigate sediment regime response to forest harvest and extremes in flow regime. Increases in sediment transport after logging were observed in the North Fork during second experiment at Caspar Creek in the 1990’s. Our analysis found turbidities were higher after logging across the range of flows including high magnitude/short duration as well as low magnitude/long duration events. However, few sediment impacts to macroinvertebrate assemblages were observed above and below tributaries with upstream harvest. Specifically, there were no differences in presence/absence of sediment sensitive taxa before and after logging. Moreover, North and South Forks sensitive taxa distributions were similar. With the South Fork, we compared 2016 and 2017 macroinvertebrate assemblages collected in July and May respectively. Statistical classification separated South Fork communities clearly by year and watershed location, reflecting a dynamic community. A six-grouping solution of 81 taxa divided based on relative abundance, watershed distribution, and functional feeding group. Natural disturbance has been high in the watershed recently with discharge regime varying five-fold since 2014, a drought year, and with higher than normal winter flooding in 2017. Sediment sensitive taxa were distributed in two groups of the six and showed no distinguishable patterns. However, overall patterns of the whole macroinvertebrate community structure between years and watershed locations were observed in the classification. Introduction Watershed research at the Caspar Creek Experimental Watersheds is among the most intensive and long- term that has been conducted anywhere in the world. The experimental watersheds consist of two paired basins, the North Fork (NF, 473-ha) and the South Fork (SF, 424-ha). The discharge record at these basins is nearly continuous since 1962 and wet season discharge records from several North Fork tributaries date back to 1985. In addition, water quality measurements, including suspended sediment concentrations (SSC) complement much of these streamflow data. Research is conducted jointly by the US Forest Service Pacific Southwest Research Station and the California Department of Forestry and Fire Protection (CAL FIRE). The watersheds, located on Jackson Demonstration State Forest in coastal northern California, are managed to produce timber in a controlled experimental setting. The old growth coast redwood -- Douglas-fir forest was logged from 1860 to 1904, long before the experimental watersheds were established in 1960. The original harvest included clearcutting, broadcast burning, and log transportation by oxen and splash dam. Following calibration from 1962 to 1967, treatments were initiated in SF (Phase 1) in 1967 and 1971-73. The North Fork served as a control watershed until 1985 when Phase 2 treatments were begun. For the first experiment (Phase 1), 65% of the SF volume was removed by selection harvest and tractor-yarding prior to implementation of the modern California Forest Practice Rules. For the second experiment (Phase 2), 15% of NF was clear-cut in 1985. Road construction and partial clear-cut harvest continued in the remainder of NF from 1989 to 1992 (35% NF harvest) with three tributaries

1. 1. Catchment Aquatic Ecology, Eugene, OR, [email protected] 2. Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR

gauged as undisturbed controls, five gauged tributaries clear-cut, four nested gauges in partial clear-cuts, and mostly cable yarding (Keppeler, 2012). NF logging occurred using the regulations established by the State Legislature in 1973. Research has focused on logging effects on streamflow and sediment production but has also addressed impacts on water temperature, nutrients, and organic matter regimes (Cafferata and Reid, 2013). Results have been influential both in watershed science and forest management (Cafferata and Reid 2013) and will continue to be a source of relevant information as a third experiment is implemented (Dymond 2016). For example, the Phase 2 experiment in the NF was designed to evaluate cumulative watershed effects by monitoring a network of nested sub-watersheds. The applied research on logging treatments (clear- cut vs selective harvest) and logging methods (tractor vs cable logging) will provide essential information for best management practices (BMP) development. Although the research effort has evolved through time, erosion and sediment transport remain a primary focus. Sediment production has been measured annually at the North and South Fork weir basins since 1962. Suspended sediment concentrations (SSC) were measured initially using fixed stage and manual depth- integrated sampling, and later using flow and turbidity-based automated sampling. The physical measurement of both weir pond deposition and suspended load allows for total sediment export to be estimated (Lewis, 1998) and sources of sediment (Rice et al., 1979) to be identified. Results have been described extensively and numerous papers have consistently reported sediment increases following logging (e.g., Rice et al. 1979; Ziemer, 1981, 1998; Lewis et al., 2001; Keppeler, 2012). How fine sediment regime impacts biology varies, from catastrophic impacts of high flow and elevated SSC that create very poor short-term habitat conditions, to elevated long-term SSC that change conditions less dramatically. High turbidity affects fish behavior (e.g., feeding) and larger grained sediment (coarse sand) can fill pools and clog interstitial spaces for benthic organisms while moving through a basin (Relyea et al., 2011). Comparing the extent of an event, both magnitude and duration, is another physical approach for evaluating sediment regime that will be used here. All these physical methods are robust tools to understand sediment regime in assessing water quality. One shortcoming in their use is that actual biological impacts cannot be directly assessed. Biological assessment approaches have been developed by water quality agencies throughout the world. In California, a well-developed and recognized set of protocols has been created for wadable streams (Ode et al., 2016). These new tools can be used as multiple lines of water quality. In the Caspar Creek Experimental Watersheds, there have been irregular measurements of instream biota, in contrast to the comprehensive efforts in the measurement of physical water quality characteristics. To date, there have been three primary investigations of instream biota (Table 1). From 1986 to 1994, Bottorff and Knight (1996) did a thorough study of instream animals (invertebrates) and plants (algae) in the North Fork during the Phase 2 experiment. In 2008, Cummins and Malkauskas (2008) reported on instream conditions in both basins with a focus on ecological relationships. Most recently the California Aquatic Bioassessment Laboratory has begun annual macroinvertebrate surveys along the South Fork as part of the Phase 3 experiment, beginning in 2016. Combined, these efforts cover 33 years (1986-present). Note that comparisons are complex because the instream invertebrate studies were done at different times, at different locations, and using different approaches to sampling (Table 2). Therefore, interpretations are less thorough than if those factors were more similar. Yet that cannot limit data usage, as biological data is a rare resource. Here, we attempt to carefully explore biological comparisons with multiple tools. In the examination of silvicultural activities and their impacts, instream fish and other biota are a concern. Specific knowledge of activities that may lead to sediment export from uplands to riparian systems has

led to well-developed techniques (Best Management Practices - BMPs) that are designed to minimize sediment delivery to streams. There is a considerable body of literature regarding BMPs, with most regions having developed and refined the practices that best fit local needs (Megahan et al., 1972; Ice and Schilling, 2012; Edwards et al., 2016; Cristan et al., 2017). Sediment BMPs are most commonly associated with roads; however, as observed in the Caspar Creek research (Cafferata and Spittler, 1998; Keppeler and Lewis, 2003; Reid and Keppeler, 2012; Reid et al. 2010) there are other sediment sources that require other types of practices as part of a comprehensive BMP plan (e.g., reduction of landslide risks, headward gully expansion). The impacts of changes to fine sediment regime on biota have been described (Waters, 1995) and quantified for some fishes (Newcombe and MacDonald, 1991; Diehl and Wolfe, 2010). The use of this information may require more refinement for broad use and less is understood with lower trophic biota, such as invertebrates and algae. We have long known the importance of substrate as a determinant to invertebrate community composition (Minshall, 1984). Therefore, an instream biological measure of sediment regime that could reinforce physical measures as well as perhaps detect less obvious chronic impacts of changes to sediment regime could be valuable. Macroinvertebrates offer several characteristics that are useful for an analysis of biological response to disturbance: they are functionally diverse, they integrate water quality conditions through time, and information for taxa sensitivity to fine sediment pollution is developing. Two unique indices designed to measure the changes in the fine sediment condition have recently been developed in the Pacific Northwest region (Relyea et al., 2011 and Hubler et al., 2016). These two studies focused on different particle sizes within the size range of fine sediment particles (< 2 mm - Relyea et al., 2011, < 0.06 mm - Hubler et al., 2016). This may allow for evaluation of changes to the macroinvertebrate community from excessive sediment inputs and impacts with respect to grain size. The impacts of fine sediment will vary, with smaller suspended material fouling feeding structures and limiting visibility (Waters, 1995; Suren and Jowett, 2001), whereas larger size material can bury and fill habitats (Suren, 2005). Macroinvertebrate samples with the appropriate level of taxonomic identification, preferably to species, can be evaluated with both indices. In the three sampling efforts spanning 33 years we compare the instream macroinvertebrate communities with tools that focus on sediment sensitivity of specific taxa and community organization. The taxa specific method uses a presence and absence approach in each study. For recent collections in the South Fork we use relative macroinvertebrate abundances to classify sites and years based on similarity of community structure. Methods This evaluation uses pre-existing data and relies strongly on previous analyses and interpretation. Additionally, three tools were applied to specifically address fine sediment regime and biological responses. First, we conducted an analysis of magnitude and duration of fine sediment conditions. Second, we evaluated three macroinvertebrate data sets with a fine sediment index based on macroinvertebrate taxa. Third, we classified 2016 and 2017 South Fork macroinvertebrate communities with an emphasis on functional feeding groups (FFG) and sediment sensitivity. Suspended Sediment Magnitude and Duration Analysis The suspended sediment data in the Caspar Creek watersheds are among the most comprehensive available and the sediment regime continues to be a focus of the project, with Phase 3 experiment including detailed watershed-scale water budget research (Dymond, 2016). Overall sediment loads in both the South and North Fork watersheds had essentially recovered to pre-treatment levels within a decade

of logging (Thomas, 1990; Lewis, 1998), although subsequently showed renewed increases (Keppeler et al., 2009). The quality of the Caspar Creek data sets attracts other researchers with other approaches. Arismendi and Penaluna (2015) analyzed the magnitude and duration of suspended sediment concentrations before and after harvest in the North Fork. This approach allows an inferred biological response delineated by sediment regime with duration and magnitude of suspended sediment conditions (Newcombe and Jensen, 1996 and Diehl and Wolfe, 2010). The fine scale (10-min) suspended sediment data from Caspar Creek between 1986 and 1997 (4+ million observations) estimates the duration and magnitude of suspended sediment relationships. For a set of storms (events = 16) we calculated durations of excursions above several quantiles representing the magnitude of suspended sediments. We plotted these relationships for the entire North Fork and individual sub-basins before and after logging. Differences at each magnitude for each duration describes the treatment differences across sediment regime. Sediment concentrations for events are in similar format as used in Newcombe and Jensen (1996), so they can be compared to the described criteria of increasing sensitivity: avoidance, physiological stress, and reduced growth rates. Macroinvertebrate Community and Fine Sediment Regime Macroinvertebrates have been collected in the Caspar Creek drainage at various times since 1987 (Table 1). Information on instream communities prior to 1980's is not available.1 Hess (1969) collected adult aquatic and terrestrial insects during road construction in the South Fork. The first full instream macroinvertebrate study was part of a larger aquatic ecology study conducted by Bottorff and Knight (1996). In the North Fork watershed macroinvertebrates were collected over a nine-year period during the Phase 2 experiment, before and after forest harvest treatment (no harvest or clear-cut) (Figure 1, Cafferata and Reid, 2013). The goal of the project was to evaluate macroinvertebrate assemblage, benthic algae community, and instream litter processing before and after logging. Here we will only examine their macroinvertebrate data and summarize overall conclusions. Table 1. Caspar Creek Watershed Phases and macroinvertebrate investigations during each Phase.

Project Phase Location Year Silvicultural Treatment Instream Biotic Components Phase 1 South Fork 1962-1985 65% volume removed None Five sub-watersheds clear-cut; 8 Macroinvertebrates and Phase 2 North Fork 1985-1996 sub-watersheds partial clear-cut Algae (North Fork only) N and S Forks Macroinvertebrates and 2008 Downstream investigation and Mainstem Instream Processes Road rehabilitation, commercial Phase 3 South Fork 2011- Macroinvertebrates thinning

1 Burns (1972) provides limited macroinvertebrate data for the South Fork following road construction that occurred in 1967.

Figure 1. North and South Forks of Caspar Creek (Figure from USFS PSW website).

Bottorff and Knight (1996) sampled macroinvertebrates each year in the North Fork by placing twenty rock packs throughout a stream reach, which were collected after 60 days for colonization (Table 2). Timber harvesting and road construction occurred from 1989 to early 1992, allowing three years of pretreatment data. In the experiment five sub-basins were clear-cut and three left as controls. In total, 13 monitoring stations were installed, eight in headwater drainages and the remainder located downstream to allow treatment effects to be tracked downstream, evaluating cumulative effects of logging. Due to the steep terrain in the upper North Fork watershed and the necessary road building, detectable changes in the instream biota resulting from changes in the sediment regimes were anticipated (Bottorff and Knight, 1996). Table 2. Comparison of instream sampling macroinvertebrate methods on three highlighted studies.

Study Team Sampling Locations Years Collection Method North Fork, 5 Mainstem Sites, Sampling Rock packs (20) col. Bottorff and Knight 1986-1994 above and below Tributaries 60 days Cummins and Upper and Lower NF; Lower SF; Upper and D- Net Kicks, 3 2008 Malkauskas Lower Mainstem habitats, 250 mesh. South Fork 3 Mainstem Sites, Sampling 2016, 20171 SWAMP D-nets kicks above and below Tributary Confluences and Bioassessment Tributaries 1. Project ongoing

The second study focusing on macroinvertebrate feeding and aquatic food webs was conducted in 2008 (Cummins and Malkauskas, 2008). This study sampled both the North and South Forks of Caspar Creek (Figure 1) and put a special emphasis on macroinvertebrate functional feeding groups (FFG). This study was the only one of the three that sampled the lower mainstem of the North and South Forks, as well as below their confluence in the Caspar Creek mainstem. These locations were downstream of the other collections. The invertebrates were sampled with timed collection using a dip net at three habitat types: riffle, pools and backwaters, and plant litter (Table 2). The third collection effort is ongoing as part of the Phase 3 experiment (Dymond, 2016). The California Department of Fish and Wildlife and CAL FIRE have collected annual macroinvertebrate data since 2016 using State Water Resources Control Board’s Surface Water Ambient Monitoring Program (SWAMP) bioassessment protocols (Ode et al., 2016). We included two years (2016-17) in our analysis. Three locations were sampled in South Fork Caspar Creek: POR, RIC, and SEQ ( three small sub-watersheds Porter, Sequoyah, and Richards, 32, 17, and 14 hectares respectively) (Figure 1). At the confluence with the South Fork mainstem, samples were collected on the South Fork above and below the confluence and in the tributary. The SWAMP bioassessment protocols are comprehensive, with high quality measures of macroinvertebrates, algae, and physical habitat characteristics (Ode et al., 2016). Analysis for this paper focuses on the macroinvertebrates, which are collected by sampling a defined area with a D-frame net at 11 transects (Table 2). Sampling is distributed along each transect to cover lateral differences in habitat. The 11 sub-samples are composited (Ode et al. 2016). Bioassessment tools targeting fine sediment have been developed in the Pacific Northwest (Relyea et al., 2011; Hubler et al., 2016). The index developed by Relyea et al. (2011) uses data sets of aquatic insect distribution and abundance from throughout the Pacific Northwest Region (including Idaho and Montana) to assess responses to < 2 mm sediment size particles from the pebble count data collected during invertebrate sampling. Relationships between taxa presence/absence and fine sediment conditions for over 800 macroinvertebrates across the region were evaluated. The Fine Sediment Biotic Index (FSBI) was developed with 206 broadly distributed taxa, with 108 taxa responding to a fine sediment gradient (Relyea et al., 2011). Relative responses to pebble count fine sediment assessments were divided into categories from extreme sensitivity to no discernible effect. With each set of results, we calculate FSBI, recognizing that field and laboratory methods are different for each study, so comparisons are examined with caution. First, we identified taxa in each study that had a FSBI designation. The longer-term Bottorff and Knight (1996) study allows for before and after treatment comparisons over eight years. To calculate FSBI score, taxa presence was multiplied by sensitivity score (20 - extremely sensitive, 15 - highly sensitive, 10 - very sensitive, and 5 - sensitive) and summed. There were no instream invertebrate sampling in the South Fork until 2016, and calculated FSBI for samples collected in 2016-17. Taxonomic differences due to levels of effort and changes in the classification of taxa names across studies were refined as possible with available data. Presence of species was assigned from any collection (all samples combined). The taxa match between the FSBI and data sets were: five of same species; thirteen at the same taxonomic level of the index. The four other taxa from the data sets were genera that had more than one species identified by the index. Where that genus was present, the least sensitive designation was assigned. Macroinvertebrates collected by the SWAMP Bioassessment project during 2016-17 were classified with a two-way method (Madeira and Oliveira, 2004) that classifies sites by successively pairing assemblages with the most similarity and then classified macroinvertebrate taxa based on their distribution and

abundance at the sites (McCune and Mefford, 2011). We truncated the full assemblage of 151 taxa by removing 70 very rare taxa (< 0.0002 % of total abundance), leaving 81. For this analysis, sample abundances were square root transformed prior to any further analysis. Taxa were categorized by functional feeding group (CF – collector-filterer, CG – collector gatherer, OM – omnivore, P – predator, SC – scraper, SH – shredder). Results and Discussion Sediment Regime Sediment yield before and after logging is one of the foci of the Caspar Creek project. The Phase 1 and 2 experiments showed increases in sediment yield after logging (Lewis et al., 2001). Yields were greater with ground-based logging conducted prior to implementation of the modern California Forest Practice Rules (South Fork Phase I experiment). Sediment yields increased in both watersheds after logging and began to recover after 10 years (Keppeler et al., 2012). Increases in peak flows post-harvest increased instream erosion, which was a significant source of fine sediment after North Fork partial clearcutting (Keppeler et al., 2012). Both road-related and hillslope landslides were primary contributors to peak sediment transport which caused renewed increases in sediment yields during subsequent decades (Keppeler et al., 2009). Additionally, landslides inputs created peak suspended sediment concentrations which affected downstream conditions (Cafferata and Reid, 2013). These published results of the project document detailed information on the sediment regime of the Caspar Creek Experimental Watersheds through more than 50 years (Cafferata and Reid, 2013). In our analysis, we compared suspended sediment magnitude and duration relationships. Suspended sediment concentrations (SSC) were higher after the harvest than before at the outlet of the North Fork for all event durations, ranging from small fractions of a day as peak flow to higher longer-term measures (Figure 2). Comparing various levels of impairment to fisheries requirements, as described by Newcombe and Jensen (1996), the lowest diagonal in Figure 2 (expected threshold for fish avoidance) is the least severe fish response. The SSC magnitude and duration curves are above the avoidance standard both before and after harvest (Figure 2). The post treatment SSC magnitude and duration shifted slightly towards increasing severity of biological impairment (Figure 2), which in the model equates to moderate physiological stress in fish (Newcombe and Jensen, 1996).

NF_pre NF_post

1000

)

-1

100

average SSC (mg L average SSC 10

1 0.01 0.1 1 10 event duration (days) Figure 2. Pre- and post-suspended sediment magnitude and duration relations categorized by event duration for the North Fork of Caspar Creek.

Figure 3. Pre and post suspended sediment magnitude and duration relations categorized by event duration at clear-cut sub-watersheds (left) and partial-clear-cut sub-watersheds (right) in the North Fork of Caspar Creek. Thresholds of impairment to fish (Newcombe and Jenson, 1996) are diagonals across range of durations.

In some of the sub-watersheds SSC magnitude and duration showed differences, while others did not after harvest (Figure 3). While cumulatively there may be an obvious difference downstream (Figure 2), in the headwaters only one site (EAG) clearly changed (left side - Figure 3) across the range of measured SSC magnitudes. Post-treatment suspended sediment concentrations were not always higher than pretreatment conditions in sub-watersheds, particularly at the low to moderate magnitude event sizes (Figure 3), although at the peaks with shortest time interval there were, in some cases, substantial differences (note the log scale on the axes) among sub-watersheds. Larger sub-watersheds DOL and JOH (77 and 55 hectares, respectively), with nested sub-watersheds upstream, have large differences at peak

events, suggesting a size effect for the largest flows even for short durations (Figure 3). In addition, for the smaller watersheds (see the left side of Figure 3, except for KJE) both pre and post relationships were closer to Newcombe and Jenson’s (1996) first diagonal than the larger watersheds on the right, suggesting less stressful conditions for biota (Figure 3). The magnitude-duration display of SSC data allows inspection of possible impacts across a range of conditions (Figures 2 and 3). This range includes peaks and extended time (i.e., a week or more) where the concentration remains elevated. The longer duration conditions are clear in Figure 2, where pre- harvest (SSC) is 30-40 mg L-1 for durations of 1-5 days versus more than 60 mg L-1 SSC for post-harvest flow durations up to three days. In no case did any of the magnitude and duration values extend to conditions that elicit physiological impairment of fish based on the Newcombe and Jensen (1996) thresholds, although increased durations shift towards possible cumulative stress (Figure 3).

While elevated suspended sediment concentrations likely influence all instream biota, the thresholds developed based on fish species may not describe biotic responses from other taxa. Impacts to macroinvertebrate populations to changes in sediment regime include disruption in feeding, changes in locomotive abilities, or burial (Waters, 1995). Sub-lethal influences are subtler and variable across lower trophic taxa. Fine Sediment Regime and Macroinvertebrates During the more than 60 years of research conducted at the Caspar Creek Watershed Study there have been numerous advancements in our knowledge of aquatic biology. Consequently, long-term comparisons require some restraint in interpretation. Here we apply an index that was developed with habitat data collected from outside northern California. Habitat preferences of individual species (e.g., % fine sediment) should be similar, although local factors can confound responses (e.g., other stressors). The fine sediment biotic index classifies 108 taxa that show sensitivity to fine sediment. Twenty-two of them were found in the Caspar Creek macroinvertebrate collections (Table 3). Not all 22 taxa were found during all three macroinvertebrate collections (Table 3). There were four taxa (Heterlimnius spp., Serratella spp., Z. cinctipes and Parapsyche spp.) that were not collected in all studies (Table 3). None of the taxa absent at a study were abundant in either of the others, indicating low abundance and may have been undetected. The FSBI classified taxa are from across a range of those taxa’s taxonomic and ecological characteristics (Table 3). Most of them are common taxa of the orders Ephemeroptera, Plecoptera, Trichoptera, and Coleoptera and from all functional feeding groups (FFGs; Table 3). Among the FFGs, scraping mayflies (Heptageniidae) were well represented, with predators from each order, shredding stoneflies, and caddisflies with a variety of feeding approaches present (Table 3). The North Fork Caspar Creek research by Bottorff and Knight (1996) directly compared instream responses to logging before and after logging. There was very little variability in FSBI throughout the North Fork experiment, neither between seasons, across seasons before and after treatment, or before and after treatment (Figure 4). The number of sensitive taxa were similar for each sample, with 19 to 21 of the 22 FSBI taxa found across all studies. The species present differed for a few taxa that were less common (Table 3), otherwise the results appear no different before and after harvest in the North Fork in the 1990’s (Figure 4). The comprehensive analysis of Bottorff and Knight which used a variety of metrics that split analysis by composition, density, or FFG, found mixed results. At all sites biological diversity and scraper densities

increased after logging, yet other metrics varied. Overall, they concluded there was no evidence of adverse sediment effects to instream conditions after logging, based on the similarity of macroinvertebrate assemblages above and below tributaries with upstream harvest (Bottorff and Knight, 1996). The Bottorff and Knight project included an intensive study of instream algae and riparian leaf decay rates in the North Fork. In brief, they found algae composition changed and biomass increased, and leaf decay rates increased after logging. The changes continued for a few years after logging (Bottorff and Knight, 1996). Table 3. Presence of FSBI taxa collected during the Bottorff and Knight (1996) study from 1986-1994, Cummins and Malkauskas in 2008, and the 2016 SWAMP Bioassessment survey. All sites were combined for each study to establish presence. Sensitivity scores are from the FSBI model categorized as extremely sensitive, very sensitive, moderately sensitive, and sensitive.

California

Order Family Taxa SensitivityClass Functional Feeding Group and Bottorff Knight Cumminsand Malkauskas 2016 Bioassessment Coleoptera Elmidae Narpus Sen CG P P P Heterlimnius Sen CG A A P Pelecorhynchidae Glutops Sen P P P P Tipulidae Antocha Sen OM P P P Ephemeroptera Ephemerellidae Drunnella Sen P P P P Serratella Sen SC P P A Heptageniidae Cinygmula Sen SC P P P Epeorus Mod SC P P P Ironodes Sen SC P P P Nixe Sen SC P P P Rithrogena Very CG P P P Leptophlebiidae Paraleptophlebia Mod CG P P P Gomphidae Octogomphus specularis Sen P P P P Plecoptera Leuctridae Despaxia augusta Ext SH P P P Nemouridae Zapada cinctipes Sen SH P A P Perlidae Calineuria californica Mod P P P P Hesperoperla Very P P P P Trichoptera Glossosomatidae Glossosoma Mod SC P P P Hydropsychidae Parapsyche Sen CF P A P Limnephilidae Ecclisomyia Ext CG P P P Rhyacophilidae Rhyacophila Mod P P P P Uenoidae Neophylax slendens Mod CG P P P Sensitivity Classes Ext -Extremely sensitive, Very - very sensitive, Mod - moderate sensitivity and Sen - sensitive. A and P are absent and present in all collections. Functional feeding Groups - P - Predator, CG - Collector-gatherer, CF - Collector-filterer, SC - Scraper, SH - Shredder, and OM - Omnivore.

The new biological assessment of South Fork Caspar Creek at three tributary confluences has 2016 and 2017 data available (CDFW, 2017; unpublished). The 2016 and 2017 FSBI scores were higher along the mainstem of the South Fork in 2017 (Figure 5). FSBI scores were slightly higher values at mainstem South Fork sites in 2017 than 2016 with one to three more of FSBI taxa (Figure 5). In the tributaries results were variable (Figure 5).

140 120 100 80 60 FSBI Score FSBI 40 20 0

FSBI Total Linear (FSBI Total)

Figure 4. Fine sediment index total scores (y-axis) in North Fork Caspar Creek before and after timber harvest. Least squares trendline is included.

120 100

80 Score

60 FSBI 40 20 0 PORa PORb SEQa SEQb RICa RICb POR SEQ RIC

2016 2017

Figure 5. Comparison of fine sediment index (all data combined) in South Fork tributaries and mainstem sites in 2016 and 2017 (POR = Porter, RIC = Richards, SEQ= Sequoyah). Small a or b indicate sampling above or below tributary confluence, samples without lower case qualifier were collected in the headwater tributary.

In macroinvertebrate community assessment of the South Fork we observed changes between 2016 and 2017. Two-way classification grouped the sites (Y-axis) by year and then stream size (Figure 6). At all mainstem sites, both above and below confluences, the macroinvertebrate assemblages of 2016 and 2017 mainstem sites grouped separately (Figure 6). Furthermore, the tributaries were more similar to one another and formed an entirely separate group (Figure 6).

Figure 6. Classification of 2016-17 macroinvertebrates in South Fork Caspar Creek by two years (horizontal-y-axis) and 81 taxa (vertical-x-axis). Relative percent abundance represented by color intensity. Y- axis designated by year (16 or 17) and site (P = Porter, R = Richards, S = Sequoyah). Small a or b indicate sampling above or below tributary confluence, samples without lower case qualifier were collected in the headwater tributary. Each taxa has label with a FFG designation (CF- collector-filterer, CG- collector gatherer, OM – omnivore, P – predator, SC – scraper, SH – shredder) with a number for individual identification. Six x-axis groups are labelled A-F. Taxa are listed in Appendix 1.

Divisions along the X-axis (Fig. 6) of the classification were driven by the distribution and abundance of 81 taxa after removing very rare taxa. We classified the aquatic macroinvertebrates into six groups (A-F). Each group was unique; there were sets of taxa within each group that differed dramatically between years or stream sizes. Group A was comprised of mostly rare taxa, with a slight increase in abundance at headwater tributaries (note mainstem 3-4th order, Figure 6; see Appendix 1 for taxa list.). Overall, in the study there were 151 macroinvertebrate taxa, but we removed 70 of them that were rarer than those in Group A. Group B was noteworthy as many of the taxa were more abundant in 2016 than 2017; differences were maintained with the headwater tributaries. Groups C and D were complex, and they could be divided further (Figure 6). One difference was that many of the Group C taxa were in the tributaries, and the opposite was true for much of Group D. Group E was similar than Group A, with rarer taxa that did not pair easily. Group F was comprised of the common taxa, and those taxa were largely similar across the comparisons (Figure 6) comprising 68% of

total abundance (Figure 7). When percent functional feeding group sorted total abundance for each group, each group exhibited a distinct pattern (Figure 8). Figure 7 and 8 provide an insight into the ecological organization of the South Fork. As most of the common species vary little across location and time, other taxa (perhaps with less viable populations) respond to habitat change more readily. The taxa in these groups can be sorted by other characteristics. Our earlier result with FSBI found few differences in our comparisons of sediment sensitive taxa. Of the 22 FSBI taxa, some were rare and not included in this classification, so 13 were among the 81 taxa. Ten were in Groups C and D, suggesting taxa within those groups may be responding to an underlying gradient related to sediment regime in community organization. Most of the ubiquitous taxa grouped together, leaving the less abundant and rare taxa to illustrate differences (Figure 8). A difference between the two years is shown in Group B, with most of the taxa in the group more abundant in 2016 both in the mainstem and tributaries (Figure 6). These apparent changes in the community between the two years suggests a common watershed-wide impact. Broader impacts at watershed scale may include differences on the duration and magnitude of hydrologic extremes between years (Table 4). In particular, the drought of 2014 shrunk available habitat and there was a large winter storm between the late spring 2016 and 2017 samples. These hydrologic extremes, at least the 2017 extreme flows, likely triggered the changes in density, particularly in the mainstem, in the Group B taxa (Figure 6).

1% 5% 9% A B 16% C D E 1% 68% F

Figure 7. Abundance of Groups A-E identified in Figure 6 as % total abundance.

Figure 8. Relative abundances of the functional feeding groups in Groups A – E identified in Figure 6. FFG designations are: CF- collector-filterer, CG- collector gatherer, OM - omnivore, P - predator, SC - scraper, SH - shredder.

None of the three macroinvertebrate collections directly compared the North and South Forks of Caspar Creek. The Bottorff and Knight (1996) work was intensive in the North Fork and the SWAMP Bioassessment study applies in-depth protocols to South Fork biota; neither study sampled the other fork. The Cummins and Malkauskas (2008) study had sites at the lower reach of the two experimental watersheds and below their confluence, and the two lower reaches of the forks showed a high degree of similarly in the aquatic macroinvertebrate assemblages. The North Fork has some steeper channels that likely support some taxa that may not be found at the South Fork due to underlying habitat conditions rather than any of the silvicultural treatments. Historically, prior to the first harvest of the old-growth forest, instream conditions had more large wood (Napolitano 1996), a different channel configuration, and a sediment regime with more stored deposited sediment. Consequently, in those habitats there could have been other taxa present, current taxa in different relative abundances, and taxa we see today that were not present. Without access to actual data, the best we can do is evaluate from when information was first available. For Caspar Creek, we can go back to 1990. This reexamination of both the suspended sediment and biologic data with different tools shows similar results to earlier efforts. The higher sediment load following timber operations has been well documented (e.g., Keppeler, 2012) and shown again here. Suspended sediment peak concentrations were higher after logging stayed higher during lower flows for longer duration. The elevated SSC for extended periods could be a more significant change for benthic invertebrates as a chronic stressor. On the biological side, as with Bottorff and Knight analysis, there is no clear response by the macroinvertebrate assemblage to the higher suspended sediment load. Bottorff and Knight (1996) speculated that changes in the macroinvertebrate community may have occurred after the first harvest (>90 years prior) and shifts in assemblage structure including the loss of sensitive species. However, first two years of the new bioassessment effort observed changes, or perhaps better termed adjustments, in the macroinvertebrate community. These changes were likely instigated by a natural disturbance. A better understanding of these adjustments and what cause them could be a useful tool to assess aquatic conditions and in including streams in multi-resource forest management.

In summary we found: ● Magnitude and duration suspended sediment analysis provided a robust view of conditions across a range of event sizes and time periods (e.g., before and after timber harvest). ● A suite of taxa found to be sensitive to fine sediment elsewhere inhabits the Caspar Creek watershed. ● We found no distinct difference in sediment sensitive taxa distribution in North and South Forks, or any discernible difference before and after the Phase 2 experiment silvicultural treatments in the North Fork. ● The difference between 2016 and 2017 macroinvertebrate assemblage in the South Fork provides an example of how natural disturbance from hydrologic extremes may play a role in shaping instream communities. ● Biological richness of macroinvertebrates includes many rare species; additional sampling will likely identify more species, particularly in the headwater tributaries.

Acknowledgements Project was supported by California Department of Forestry and Fire protection contract # 8CA03674. We appreciate the assistance and suggestions of cooperating scientists Elizbeth Keppler, Jayme Seehafer, and Joseph Wagenbrenner of the USFS Pacific Southwest Research Station, Pete Cafferata California Department of Forestry and Fire Protection, and James Harrington California Dept of Fish and Wildlife.

Literature Cited

Arismendi, I. and B. Penaluna. 2015. Describing fine sediment delivery regimes in streams using biologically relevant metrics across multiple spatiotemporal scales. Unpublished Report. Bottorff, R.L. and A.W. Knight. 1996. The effects of clear-cut logging on the stream biology of the North Fork of Caspar Creek, Jackson Demonstration State Forest, Fort Bragg, CA. Burns, J.W. 1972. Some effects of logging and associated road construction on northern California streams. Transactions, American Fisheries Society 101(1):1-17. https://www.fs.fed.us/psw/publications /4351/Burns72.pdf Cafferata, P.H. and T.E. Spittler. 1998. Logging impacts of the 1970’s vs. the 1990’s in the Caspar Creek watershed. 1998. In R.T. Ziemer, Editor, Proceedings of the conference on Coastal Watersheds: the Caspar Creek Story, Ukiah, CA pp. 103-115. PSW GRT-168. USDA Forest Service, Pacific Southwest Forest and Range Experiment Station, Albany, Ca. Cafferata, P.H. and L.M. Reid. 2013. Applications of long-term watershed research to forest management in California: 50 years of learning from the Caspar Creek Watershed study. California Forestry Report No. 5. Sacramento: State of California, The Natural Resources Agency, Department of Forestry and Fire Protection. 114 p. CDFW (California Department of Fish and Wildlife). 2017. Caspar Creek taxa list for 2016 (Excel spreadsheet). Unpublished data. James Harrington and Peter Ode, DFW, Rancho Corvoda, CA. Cristan R., W.M. Aust, M.C. Bolding, S.M. Barrett, J.F. Munsell. 2017. National status of state developed and implemented forestry best management practices for protecting water quality in the United States. Forest Ecology and Management. https://doi.org/10.1016/j.foreco.2017.07.002. Cummins, K.W. and D. Malkauskas. 2008. Macroinvertebrate Inventory of the Caspar Creek watershed. Final Report the Cal Fire. Diehl, T. H. and W. J. Wolfe, 2010: Suspended-sediment concentration regimes for two biological reference streams in middle Tennessee. Journal of the American Water Resources Association, 46, 824-837. Dymond, S.F. 2016. Caspar Creek Experimental Watersheds Experiment Three Study Plan: The influence of forest stand density reduction on watershed processes in the South Fork Edwards, P. J., F. Wood, and T.L. Quinlivan. 2016. Effectiveness of best management practices that have application to forest roads: a literature synthesis. Gen. Tech. Rep. NRS-163. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 171 p. Hess L. J. 1969. The effect of logging road construction on insect drop into a small coastal stream. Thesis. Humboldt State University, Arcata, CA. Hubler, S. D.D. Huff, P. Edwards, and Y. Pan. 2016. The Biological Sediment Tolerance Index: Assessing fine sediments conditions in Oregon streams using macroinvertebrates. Ecological Indicators, Volume 67, Pages 132–145.

Ice, G.G., and E.B. Schilling. 2012. Assessing the effectiveness of contemporary forestry best management practices (BMPs): Focus on roads. Special Rep. 12-01, National Council for Air and Stream Improvement, Inc. (NCASI), Research Triangle Park, NC. 23 p. Lewis, J. 1998. Evaluating the impacts of logging activities on erosion and sediment transport in the Caspar Creek watersheds. In: Ziemer, R.R. (Technical coordinator) Proceedings of the Conference on Coastal Watersheds: the Caspar Creek Story, May 6, 1998; Ukiah, CA. General Tech. Rep. PSW GTR-168. USDA Forest Service, Pacific Southwest Research Station Albany, CA. pp. 55-69. Lewis, J., S.R. Mori, E.T Keppeler, and R.R. Ziemer. 2001. Impacts of logging on storm flows, flow volumes, and suspended loads in Caspar Creek California. In M.S. Wigmosta and S.J. Burges, eds. Landuse and Watersheds: Human Influence on Hydrology and Geomorphology in Urban and Forest Areas. Water Science and Application V. 2, pp. 85-125. American Geophysical Union, Washington DC. Keppeler, E. T. 2012. Sediment production in a coastal watershed: legacy, land use, recovery, and rehabilitation. In: Standiford, R. B.; Weller, T. J.; Piirto, D. D.; Stuart, J. D., tech. coords. Proceedings of coast redwood forests in a changing California: A symposium for scientists and managers. Gen. Tech. Rep. PSW-GTR-238. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. pp. 69-77. Keppeler, E. T., J. Lewis, T.E. Lisle. 2003. Effects of forest management on streamflow, sediment yield, and erosion, Caspar Creek Experimental Watersheds. In: Renard, K. G.; McElroy, S. A.; Gburek, W. J.; Canfield, H. Evan; Scott, R. L., eds. First Interagency Conference on Research in the Watersheds, October 27-30, 2003. U.S. Department of Agriculture, Agricultural Research Service; 77-82. Keppeler, E., L. Reid, T. Lisle, Thomas. 2009. Long-term patterns of hydrologic response after logging in a coastal redwood forest. Pg. 265-272 In: Webb, R.M.T., and Semmens, D.J., eds., 2009, Planning for an uncertain future—Monitoring, integration, and adaptation. Proceedings of the Third Interagency Conference on Research in the Watersheds: U.S. Geological Survey Scientific Investigations Report 2009-5049, 292 p. Madeira, S. C. & A. L. Oliveira. 2004.Biclustering algorithms for biological data analysis: a survey. IEEE Transactions on Computational Biology and Bioinformatics 1:24-46. McCune, B. and M. J. Mefford. 2011. PC-ORD. Multivariate Analysis of Ecological Data. Version 6.08. Megahan, W.F. and W.J. Kidd. 1972. Effect of logging roads on sediment production rates in the Idaho Batholith. Res. Pap. INT-123. Ogden, Utah: U.S. Dept. of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. Minshall, G.W. 1984. Aquatic insect-substratum relationships. In: Resh, Rosenburg (eds.) The ecology of aquatic insects (Praeger Publishers, New York). Napolitano, M.B. 1996. Sediment transport and storage in North Fork Caspar Creek, Mendocino County, California: water years 1980-1988. Arcata, CA: Humboldt State University; 148 p. M.S. thesis. Newcombe, C. P. and D. D. MacDonald. 1991: Effects of suspended sediments on aquatic ecosystems. North American Journal of Fisheries Management, 11, 72-82. Newcombe, C.P. and J. Jensen, 1996. Channel suspended sediment and fisheries: a synthesis for quantitative assessment of risk and impact. NAJFM 16(4): 693-727. Ode, P.R., A.E. Fetscher, and L.B. Busse. 2016. Standard Operating Procedures for the Collection of Field Data for Bioassessments of California Wadable streams: Benthic Macroinvertebrates, Algae, and Physical Habitat. California State Water Resources Control Board Surface Water Ambient Monitoring Program (SWAMP) Bioassessment SOP 004 Reid, L.M., N.J. Dewey, T.E. Lisle, and S. Hilton. 2010. The incidence and role of gullies after logging in a coastal redwood forest. Geomorphology 117: 155-169. Reid, L.M. and E.T. Keppeler. 2012. Landslides after clear-cut logging in a coast redwood forest. In: Standiford, Richard B.; Weller, Theodore J.; Piirto, Douglas D.; Stuart, John D., tech. coords. Proceedings of coast redwood forests in a changing California: A symposium for scientists and

managers. Gen. Tech. Rep. PSW-GTR-238. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. pp.163-172. Relyea, C. D., G. W. Minshall and R. J. Danehy, 2011: Development and validation of an aquatic fine sediment biotic index. Environmental Management, 49(1) 242-242. Rice, R.M., F.B. Tilley, and P. A. Datzman. 1979. A watershed’s response to logging and roads: South Fork of Caspar Creek, California, 1967-1976. USDA FS, Pacific Southwest Forest and Range Experiment Station, Research paper PSW-146. Suren, A.M and I.G. Jowett. 2001. Effects of deposited sediment on invertebrate drift: an experimental study. New Zealand Journal of Marine and Freshwater Research 35:725-737. Suren, A.M. 2005. Effects of deposited sediment on patch selection by two grazing stream invertebrates. Hydrobiologia 549:205-218. Thomas, R.B. 1990. Problems in determining the return of a watershed to pretreatment conditions: techniques applied to a study at Caspar Creek, California. Water Resources Research 26(9): 2079- 2087. Waters, T. F. 1995. Sediment in Streams: Sources, Biological Effects, and Control, Monograph 7, American Fisheries Society, Bethesda. Ziemer, R.R. 1981. Stormflow response to road building and partial cutting in small streams of northern California. Water Resources Research. 17(4): 907-917. Ziemer, R.R. 1998. Flooding and streamflows. In R.T. Ziemer, Editor, Proceedings of the conference on Coastal Watersheds: the Caspar Creek Story, Ukiah, CA pp. 15-24. PSW GRT-168. USDA Forest Service, Pacific Southwest Forest and Range Experiment Station, Albany, CA.

Appendix I. Group members of 81 taxa used in two-way classification taxa designations for Figure 6 - 8. Fine sediment sensitive taxa (FSBI) in bold.

Taxa FFG Total Abundance Taxa FFG Total Abundance Group A Group D Pagastia CG8 18 Rheotanytarsus CF1 96 Heterotrissocladius CG10 37 Tanytarsus CF3 237 Limnophyes CG12 19 Narpus CG2 14 Corynoneura CG17 12 Acneus CG3 45 Brillia CG18 72 Microtendipes rydalensis grp.CG5 34 Boreochlus CG19 43 Tvetenia CG14 119 Pericoma/Thematoscopus CG27 31 Ameletus CG26 44 Sanfilippodytes P3 14 Eukiefferiella OM2 256 Rhyacophila grandis grp. P35 125 Rheocricotopus OM3 85 Bezzia/ Palpomyia P4 212 Group B Larsia P11 88 Atrichopogon CG4 44 Hexatoma P17 186 Heleniella CG9 77 Hesperoperla P31 112 Parametriocnemus CG13 174 Sialis P33 25 Zavrelimyia/Paramerina CG20 142 Rhyacophila betteni grp. P34 125 Dixa CG21 79 Zaitzevia SC2 29 Polypedilum OM1 218 Glutops SC3 108 Monodiamesa P5 161 Cinygmula SC5 84 Alotanypus P7 289 Glossosoma SC8 65 Brundiniella P8 139 Neophylax SC9 1470 Thienemannimyia grp. P12 308 Hydatophylax hesperus SH9 153 Dicranota P16 83 Nerophilus californicus SH12 50 Moselia infuscata SH4 168 Maruina lanceolata SC11 54 Soyedina SH7 202 Psychoglypha SH11 54 Group E Hydropsyche CF4 30 Group C Matriella teresa CG24 31 Stempellinella CF2 154 Macropelopia P9 17 Parapsyche CF5 34 Krenopelopia P10 34 Wormaldia CF6 74 Chelifera/Metachela P14 67 Simulium CF7 98 Cordulegaster dorsalis P18 22 Heterlimnius CG1 121 Stempellina CG7 14 Group F Krenosmittia CG11 56 Micropsectra CG6 4831 Meringodixa chalonenois P13 16 Baetis CG22 732 Oreogeton P15 72 Diphetor hageni CG23 577 Paraperla P19 12 Paraleptophlebia CG25 994 Cinygma SC4 150 Sweltsa P29 789 Ironodes SC7 110 Calineuria californica P30 344 Lara SH1 30 Skwala P32 505 Despaxia augusta SH3 174 Optioservus SC1 972 Thienemanniella SH2 1742 Malenka SH5 365 Nemouridae SH6 595 Heteroplectron californicum SH8 1291 Limnephilidae SH10 1341 Parthina SH13 575 Lepidostoma SH14 402