Macroinvertebrate Community Structure 

in the Mohawk River (NY, USA): Gradients 

in water quality conditions and 

implications for restoration 

ABSTRACT A macroinvertebrate survey of the Mohawk River (NY) was performed in 2014 and 2015. Multiplates were deployed at a total of 56 sites along a 166 km section of river between Marcy and Waterford. Results showed fluctuations in stream condition largely attributed to negative impacts of channelization and canalization of the Mohawk River on macroinvertebrate community structure. The macroinvertebrate communities were relatively un-diverse and dominated by a pollution-sensitive Chironomidae species and zebra mussel. Sensitive taxa, such as Ephemeroptera, Plecoptera, and Trichoptera, were in substantially fewer abundance. Based on the NYS DEC Biological Assessment Profile (BAP), average stream condition for the Mohawk River was considered moderately impacted. Stream condition appeared to be less perturbed in 2014 than in 2015. Despite relatively discrete water quality conditions throughout the study area, the results of this study do demonstrate the importance of habitat diversity and refugia on improving macroinvertebrate community structure and water quality in the Mohawk River. Specifically, aquatic vegetation and tributary inflow may be important drivers of macroinvertebrate diversity and help maintain comparatively healthier water quality. 

Onondaga Environmental Institute 

5795 Widewaters Parkway Syracuse, NY 13214 315‐472‐2150 • admin@oei2.org www.oei2.org 

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Table of contents

Contents I.  Introduction .................................................................................................................................... 3 

II. Methods .......................................................................................................................................... 5

a. Project Area .................................................................................................................................... 5

b. Site Selection .................................................................................................................................. 5

c. Macroinvertebrate sampling & analysis .......................................................................................... 5

d. Water quality .................................................................................................................................. 6

e. Data analyses .................................................................................................................................. 6

III. Results ............................................................................................................................................ 7

a. Macroinvertebrate community structure ......................................................................................... 7

b. Macroinvertebrate metric scores ..................................................................................................... 9

c. Spatial trends in water quality & effects on macroinvertebrate community structure..................... 11

IV. Discussion ..................................................................................................................................... 12

V.  Conclusions & Recommendations ................................................................................................. 15 

VI. Acknowledgments ......................................................................................................................... 15

VII. Literature Cited ............................................................................................................................ 16

List of Tables p.

Table 1. List of multiplate sampling sites in the Mohawk River in 2014. 19 Table 2. List of multiplate sampling sites in the Mohawk River in 2014. 20 Table 3. Descriptions of macroinvertebrate metrics used. 21 Table 4. Taxonomic groups developed for Analysis of Variance. 22 Table 5. ANOVA macroinvertebrate community composition by stream reach. 23 Table 6. ANOVA of functional feeding group composition for stream reaches. 23 Table 7. Summary of macroinvertebrate metric results. 24 Table 8. ANOVA of macroinvertebrate metric scores between sample years. 24 Table 9. ANOVA of macroinvertebrate metric scores by stream reach. 25 Table 10. ANOVA of macroinvertebrate metric scores between years by stream reaches. 25 Table 11. Summary of water quality results. 26 Table 12. ANOVA of water quality parameters between deployment and retrieval. 26 Table 13. ANOVA of water quality parameters among stream reaches. 27 Table 14. Correlation analysis of metrics and water quality parameters. 28

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List of Figures p.

Figure 1. Macroinvertebrate multiplate sampling locations in the Mohawk River in 2014. 29 Figure 2. Macroinvertebrate multiplate sampling locations in the Mohawk River in 2015. 30 Figure 3. Depiction of multiplate devices constructed and used for this study. 31 Figure 4. Schematic depicting stream reach designations. 32 Figure 5. Total macroinvertebrate abundances, by major taxonomic groups. 33 Figure 6. Percent contributions of macroinvertebrates, by major taxonomic groups. 34 Figure 7. Box plots of macroinvertebrate abundances, by stream segment. 35 Figure 8. Macroinvertebrate abundances according to Functional Feeding Group. 36 Figure 9. Percent contributions of macroinvertebrates, by Functional Feeding Groups. 37 Figure 10. Box plots of Functional Feeding Group abundances, by stream segment. 38 Figure 11. Species richness by site and year. 39 Figure 12. Species richness by stream reach. 40 Figure 13. Species richness by stream reach and year. 40 Figure 14. EPT richness by site and year. 41 Figure 15. EPT richness by stream reach. 42 Figure 16. EPT richness by stream reach and year. 42 Figure 17. NCO richness by site and year. 43 Figure 18. NCO richness by stream reach. 44 Figure 19. NCO richness by stream reach and year. 44 Figure 20. Percent dominance (DOM3) by site and year. 45 Figure 21. Percent dominance (DOM3) by stream reach. 46 Figure 22. Percent dominance (DOM3) by stream reach and year. 46 Figure 23. Shannon diversity (Hʹ) by site and year. 47 Figure 24. Shannon diversity (Hʹ) by stream reach. 48 Figure 25. Shannon diversity (Hʹ) by stream reach and year. 48 Figure 26. HBI scores by site and year. 49 Figure 27. HBI scores by stream reach. 50 Figure 28. HBI scores by stream reach and year. 50 Figure 29. Biological assessment profile (BAP) scores. 51 Figure 30. BAP scores by stream reach. 52 Figure 31. BAP scores by stream reach and year. 52 Figure 32. Spatial trends in water quality parameters in 2014. 53 Figure 33. Spatial trends in water quality parameters in 2014, by stream reach. 54 Figure 34. Spatial trends in water quality parameters in 2015. 55 Figure 35. Spatial trends in water quality parameters in 2015, by stream reach. 56

Attachment A. Taxonomic list of macroinvertebrates collected in the Mohawk River 57

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I. Introduction

The Mohawk River is the second largest river in the state of New York (Smith et al. 2010, McBride 2009), and has been of cultural and economic significance for centuries. The Mohawk river is known to Haudenosaunee as “Te-non-an-at-che, the river flowing through the mountains” (Hislop 1948). In the past, people flocked to the Mohawk Valley to profit from its transportation potential, fertile soil, and abundant aquatic life (NYSDEC 2012). Over the last century, however, the Mohawk River Basin has faced a number of challenges caused primarily by population expansion, hydrologic alterations, and changes in land use (Smith et al. 2010). As a result, ecological integrity (i.e., structure and function) of the Mohawk River and many of its tributaries has declined.

Historically, the river was characterized by riffles, pools, and still waters; these have been replaced by a series of regulated canal levels following the river’s incorporation into the New York State Barge Canal (George et al. 2016, McBride 2009, Simpson 1980). After the completion of the Erie Canal in 1918, the Mohawk River can be described as a series of permanent and seasonal impoundments (McBride 2009). At present, 135 km of the river has been modified. Within the lower 122 km, there are five permanent dams, nine moveable dams, nine locks, and five operational hydropower facilities (McBride 2009, McBride 1987). There are an additional five locks that join the Mohawk and Hudson rivers, bypassing Cohoes Falls. To date, only 10.3 km of the lower river’s length has not been incorporated into the 61-m wide and 4.3-m deep shipping channel created by the NYS Barge Canal (McBride 2009, McBride 1987). As a result, the Mohawk River has been classified into three habitat types: canal-cut (i.e., a new channel, separate from the historic channel), canalized channel (i.e., historic channel dredged for Barge Canal), and natural channel (McBride 2009, McBride 1987, Carlson 2015). The characteristics of the impoundments created by the canal vary along the stream, from smaller impoundments in the upper section to larger impoundments in the lower reach (George et al. 2016). While the ecological effects of seasonal impoundments are not well known (George et al. 2016), impoundments in general are known to positively and negatively impact water quality and ecosystem health.

Impoundments in riverine systems have been shown to modify temperature regimes (Olden and Naiman 2010), nutrient cycling (Camargo et al. 2004), macroinvertebrate diversity (Holt et al. 2015, Grubbs and Taylor 2004), biomass and production (Sedell et al. 1990), fish community structure (George et al. 2016), fish feeding (Simonin et al. 2007), and fish migration (Larinier, 2001). Numerous studies have documented the impacts impoundments have on benthic community structure (Ellis and Jones 2013). Depending on the location of the impoundment within a stream and the location of the study site, research has found that benthic community structure can be positively or negatively impacted by impoundments (Ellis and Jones 2013), in part due to the reduction of microhabitats (Simpson 1980). The consensus remains, however, that the modification of rivers due to impoundments can profoundly affect ecological integrity.

To compound the effect of significant channelization caused by the Barge Canal, the Mohawk River has also experienced localized and pervasive degradation caused by alterations to land use from urban development and agriculture. Stream quality has been found to be poorer along more urbanized sections of the Barge Canal Corridor (NYSDEC 2010). The upper section

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of the river has no known impact, but moving into the more populated area of Rome the river is known to be impaired by odors, floatables, PCBs, PAHs, pathogens, and metals (copper) (NYSDEC 2010). Downstream of Rome and Utica, the mainstem experiences minor impacts overall, with known pollution from agriculture and urban storm runoff. Nearer to Albany, the river is impacted by ammonia, nutrients, pathogens, and silt/sediment primarily from urban storm runoff and combined sewer overflows (NYSDEC 2010). Based on the New York State 303(d)listing for impaired waterbodies, the recreational use, aquatic life support, and aesthetics are found to be significantly restricted by pollutants in the Mohawk River (NYSDEC 2016, McBride 2009). The New York State Department of Environmental Conservation (NYSDEC) has identified a series of pollutants from industrial, municipal, commercial, and other sources related to urban impacts. These have been most significant in the areas of Utica and Rome (NYS DEC).

Agriculture and forest are the major land use types for the Mohawk River Basin (NYSDEC 2010). While forest cover is dominant in the Adirondack region of the watershed, agriculture is more common in the areas adjacent to the main stem of the river. The considerable amount of agricultural activity in rural subwatersheds has been known to have significant impact on water quality. Runoff caused by poor agricultural management practices has contributed to significant nutrient, silt, and sediment loading in the Mohawk River (NYSDEC 2010).

Assessments of biotic integrity have become a common and effective method for assessing stream condition, and are often relied on by resource managers and scientists to guide restoration efforts (Johnson and Ringler 2014). Benthic macroinvertebrate assemblages are a commonly used measurement for effectively and relatively inexpensively assessing stream condition. A NYSDEC macroinvertebrate survey conducted in 1972 found that the river supported fewer species than would be expected from an undisturbed river, suffered from severe toxicity from Rome to Utica (“where species richness and standing crop were extremely low”), contained excessive amounts of organic materials below Utica and Little Falls, and contained ample amounts of plant nutrients and suspended organic particulates (Simpson 1980). Subsequent macroinvertebrate surveys (1990, 1995, and 2000-2001) in the Mohawk River demonstrate varying levels of stream impairment (Bode et al. 2004), with a noticeable downstream decrease in pollution-sensitive taxa and invertebrate biomass at select stream segments (Smith et al. 2010). Temporal trends in water quality in the Mohawk River mainstem have also been observed, with two locations showing declines in water quality, one site showing an improvement in water quality, and four sites showing no change in water quality (Bode et al. 2004).

Despite the long historical dataset for several locations in the Mohawk River, a comprehensive macroinvertebrate survey within the mainstem of the Mohawk River has not been performed since the initial 1972 NYSDEC study. Furthermore, routine surveys of macroinvertebrate composition and stream assessments by the NYSDEC Stream Biomonitoring Unit are restricted to a five-year cycle at 8 locations in the Mohawk River. Therefore, in order to gain a better understanding of spatial and temporal trends in water quality in the Mohawk River, the objectives of this study were to: (1) monitor macroinvertebrate communities at 58 locations in the Mohawk River from Waterford to Herkimer between 2014 and 2015, (2) identify the environmental factors significantly impacting macroinvertebrate communities, (3) assess long-term trends in macroinvertebrate diversity and stream condition from historical data, (4) work

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cooperatively with other scientists performing fish sampling, and to (6) help fulfill the goal(s) of the Mohawk River Basin Action Agenda by making recommendations that may be used to guide future studies and restoration efforts.

II. Methodsa. Project Area

The Mohawk River watershed (8,960 km2) is the largest tributary to the Hudson River and the second largest river in New York (257 km) (NYSDEC 2010, McBride 2009). The Mohawk River originates in north central New York between the Adirondack Mountains and the Tug Hill Plateau. The river flows south into Rome, NY then flows east through the Mohawk Valley, which divides the Catskill Mountains to the south and the Adirondack Mountains to the north. It finally joins the Hudson River in Cohoes . The Mohawk River flows through five major population centers: Rome, Utica, Amsterdam, Schenectady, and the Capital District (Albany), where the lower 47 km of the river is located (NYSDEC 2010, McBride 2009).

b. Site Selection

A total of 56 sites were sampled for aquatic macroinvertebrates in the Mohawk River mainstem between 2014 and 2015 (Fig. 1 and Fig. 2). Collectively, sampling occurred along a 166-km section of the Mohawk River from Crescent Lake, in the Town of Waterford, to just above Lock 20, in the Town of Marcy. Multiplate sampling devices were deployed at 25 sites August 26-27, 2014 (Table 1) and at 31 sites July 16-17, 2015 (Table 2). At each site, multiplates were deployed in areas where there was safe accessibility by boat, comparable conditions upstream and downstream, readily visible identifiers (e.g., navigation buoys or day boards) for easy retrieval, and where potential disturbance of the multiplates (e.g., high flows from lock discharges, boat traffic) appeared minimal (i.e, outside of the navigation channel). In 2014, the multiplate at site 10 was lost prior to retrieval; therefore, only 24 macroinvertebrate samples were analyzed.

c. Macroinvertebrate sampling & analysis

Macroinvertebrates were sampled for using artificial substrates known as Hester-Dendy multiplates (Hester and Dendy, 1962). Multiplates are used in lotic and lentic systems were active sampling method (e.g., kick-net sampling) are not feasible. Due to the channelized conditions of the Mohawk River maintained for navigation purposes, the river is too deep to sample using alternative methods. Furthermore, the NYS Department of Environmental Conservation (NYSDEC) deploys multiplates in the Mohawk River for their routine macroinvertebrate surveys; allowing for temporal comparisons to be made, unbiased by differences in sampling methods. Because multiplates provide an artificial substrate uniform across all sampling sites, the macroinvertebrates that colonize multiplates are a greater indication of water quality throughout the system than substrate quality. The multiplates used in this study were a modified version of the original Hester-Dendy sampler, and one utilized by the NYSDEC (Fig. 3). Multiplates were constructed of tempered hardboard. Three square plates measuring 15.24 cm2, were fastened to an eye bolt with hardboard spacers placed in between to obtain a separation of 0.3 cm between the first and second plate and a separation of 0.9 cm between the second and third plate (Fig. 3). The total surface area available for macroinvertebrate

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colonization is 0.14 m2. Multiplates placement at each location was dependent on stream depth and the availability of a navigation buoy. If a navigation buoy was present, the multiplate was suspended from the buoy using plastic-coated cable. An identifying tag with contact information was attached to the multiplate to denote that a study was in progress. One to two bricks were attached to a cable and attached to the bottom of the multiplate to suspend the plate upright. In areas where navigation markers were not available, the multiplate was suspended from a labeled plastic bottle. In this instance, a half-sized cinder block was used to maintain the plate upright in the water column and prevent drifting from the original site of deployment. Plates were deployed to a depth of 1 m. If stream depth was less than 1 m, the multiplate was suspended directly to the cinder block.

One multiplate was deployed at each site and left for a 5-week period to allow adequate time for macroinvertebrate colonization. After the deployment period, the multiplates were retrieved by carefully and slowly bringing the entire unit to the water surface. The sampling unit was placed into a plastic bin containing river water. While still in the plastic bin, the unit was disassembled and both sides of each plate were cleaned with a plastic scraper. The bin of river water was strained through a 500 µm (US no. 35) sieve. The remaining contents were placed into a Whirl-Pak® bag and preserved in 95% ethanol.

Macroinvertebrate samples were rinsed through a 250 µm (US no. 60) sieve for subsampling. Subsampling procedures were performed according to NYSDEC methodology (Smith 2016), whereby one-quarter of the sample was placed in a Petri dish and organisms were removed until a count of 250 was achieved. If less than 250 organisms were counted, another one-quarter of sample was selected and the process repeated until a 250-organism subsample was achieved. Organisms were identified to the highest taxonomic resolution achievable, typically genus. Chironomidae and Oligochaeata taxa were slide-mounted using CMCP-10 as a clearing and mounting media. In 2014, all samples were sorted in their entirety due to low abundances and identifications were performed in-house. In 2015, this project participated in the NYSDEC Professional External Evaluations of Rivers and Streams (PEERS) Program. As part of the program, sampling methodologies followed an adapted and DEC-approved Quality Assurance Project Plan (QAPP) that required the identification of macroinvertebrates be performed by a certified taxonomist. Therefore, 2015 samples were analyzed by Watershed Assessment Associates (Schenectady, NY). Subsampling procedures were performed as previously described, using NYSDEC methodologies.

d. Water quality

Water quality was collected at each site during multiplate deployment and retrieval using a YSI 6820-v2 sonde and 650 mds handheld. Parameters measured included temperature (°C), dissolved oxygen (mg/L), pH, conductivity (ppt), and turbidity (NTU).

e. Data analyses

Seven biotic metrics designed for macroinvertebrate community data were calculated, and included: (1) measures of taxa richness (species/genera richness [RICH], Ephemeroptera-Plecoptera-Trichoptera richness [EPT], and Non-Chironomidae Oligochaeta richness[NCO]), (2) community diversity and evenness (Shannon Diversity [H´] and Dominance [DOM-3]), and (3)

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water/biotic quality assessments (Hilsenhoff Biotic Index [HBI] and Biological Assessment Profile [BAP]) (Table 3). Information for macroinvertebrate functional feeding groups (FFG) was obtained from Merritt et al. (2009) and Smith et al. (2016) and the categories used were: collector-filterer (CF), collector-gatherer (CG), predator (PRD), scraper (SCR), and shredder (SHR). The percent abundance for each FFG was calculated for each site.

The percent contribution of macroinvertebrate taxa was evaluated for each sample year by categorizing taxa into major groups (Table 4). Group categories varied slightly between years and was based on species presence. This analysis is designed to assess overall trends in multiplate colonization by macroinvertebrates in the Mohawk River, as well as help supplement the results of the DOM-3 analysis. An Analysis of Variance (ANOVA) was performed to test for significant differences (ɑ = 0.05) in macroinvertebrate community structure in 2014 and 2015. Spatial trends in water quality and macroinvertebrate community structure were made by grouping sites according to stream reach position in between canal locks, using the designations of: upper, middle, and lower. Upper reaches were sites just below a lock, middle reaches were sites approximately halfway between canal locks, and lower reaches were sites just above locks (Fig. 4). An ANOVA was performed to test for significant differences (ɑ = 0.05) in macroinvertebrate community structure and metrics results among stream reaches (i.e., upper, middle, lower), between sample years, and between years among each sample reach (year*reach). In addition, metric data for both study years was combined to test for overall significant differences (ɑ = 0.05) among stream reach for the entire study period.

ANOVAs were also performed to test for significant differences (ɑ = 0.05) in water quality values among stream reaches during multiplate deployment and retrieval. ANOVAs were performed using the statistical program R (R Core Team 2017) (Spearman rank correlation was conducted for environmental variables and assemblage metric scores to examine the environmental factors most significantly correlated with assemblage-specific metrics. Correlations were performed using the package Hmisc in the statistical program R (Harrell Jr, 2016).

III. Resultsa. Macroinvertebrate community structure

In 2014, multiplate samples were dominated by Chironomidae larvae (midges), comprising two-thirds of total abundance (Fig. 5a). The second most abundant taxa were species belonging to the Ephemeroptera-Plecoptera-Trichoptera (EPT) category, comprising approximately 11% of the total abundance. Of the EPT taxa, Ephemeroptera (family Heptageniidae) were the most prevalent, comprising over 60% of EPT abundance. Species distributions along the Mohawk River were relatively uniform, with chironomids being the most dominant taxa at 20 out of 24 sampling locations (Fig. 6a). Notable exceptions to this include Site 5, which was located just below Lock 16, and Site 7, located above Lock 15; both located in the town of Minden (Montgomery County) within the Lock 15 pool (Fig. 6a). At Site 5, Ephemeroptera dominated total abundance (80%), whereas Copepoda zooplankton were the dominant taxa found at Site 7 (84%).

In 2015, the dominant taxa found colonizing multiplates were Mollusca (gastropods & bivalves). Mollusks comprised more than 71% of the total abundance (Fig. 5b). Within the

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Mollusca category, 99.3% of the individuals were the invasive zebra mussel (Dreissena polymorpha). Chironomidae was the second most abundant taxonomic group collected from multiplates (Fig. 5b). Compared to 2014, other major taxonomic differences included the absence of zooplankton, and the presence of Nemertea and Platyhelminthes worms and Coelenterata (Hydrozoa) (Table 4). Macroinvertebrate abundances at the 2015 sampling sites did not yield any significant trends that could be attributed to downstream changes in stream condition (Fig. 6b). Chironomid larvae were especially abundant on multiplates located from Sites 7-16. These sites were located between Locks 14 and 17 (Fig. 2). At all other locations, zebra mussels were the predominant species to colonize the multiplates.

Macroinvertebrate composition throughout the Mohawk River was relatively comparable among stream reach positions in 2014. Chironomidae was the most abundant group present in all three stream reaches (Fig. 7a). Taxa abundances among the three stream reaches were not significantly different (p > 0.05) (Table 5). While EPT abundances were greater at sites located in the upper reaches, they were not significantly different from the middle and lower reaches (p > 0.05). Likewise, significant changes in macroinvertebrate community structure in 2015 were not evident, based on site position within the stream reach. Mollusca abundance varied considerably at locations in lower stream reaches (i.e., just above canal locks) (Fig. 7b). Of the three stream reaches, sampling sites located in the middle portion of the stream reach had comparatively lower mean zebra mussel abundances. These observations, however, were not statistically significant among stream reaches (p > 0.05) (Table 5).

According to FFG, collector-gatherers (CG) were the most dominant taxa found on multiplates in 2014, comprising 42% of total abundance (Fig. 8a). The remaining FFGs were relatively evenly represented in the Mohawk River, ranging between 11% and 19%. Spatial trends in FFG abundances can be attributed to the dominance of select taxa at each. While chironomid larvae were the most abundant taxa at 20 out of 24 locations, the diversity of FFGs within this group helped contribute to a diversity of FFGs represented at each site (Fig. 9a). Two notable exception, again, include Site 5 and Site 7. At site 5, the dominance of individuals from the scraper (SCR) FFG can be attributed to Heptageniidae mayflies (Ephemeroptera). At site 7, the high contribution of individuals from the collector-filterer (CF) FFG can be attributed to the dominance of Copepoda zooplankton. The distribution of CF and SCR abundances were greatest at locations in the upper reaches of the Mohawk River (Fig. 10a). However, these trends were not statistically significant (p > 0.05) (Table 6).

The dominance of zebra mussels on multiplates contributed to the dominance of CFs, comprising 78% of the total abundance in 2015 (Fig. 8b). The contribution of the remaining functional groups varied considerably, ranging between 1% and 15%. FFG group diversity is generally low at sampling sites dominated by zebra mussels (Fig. 9b). At sites were chironomids were the more abundance taxa (e.g., sites 7-16), FFG diversity is greater; most notably a greater proportion of CGs and shredders (SHR) (Fig. 9b). For all stream reaches, CFs were the most abundant and widely distributed FFG (Fig. 10b). For nearly all FFGs, differences in abundance among stream reaches were not significant (p > 0.05 (Table 6). The one exception is the SCR FFG, which had abundances significantly greater (p < 0.05) in the upper reaches than in the middle and lower reaches (Table 6).

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b. Macroinvertebrate metric scores

Macroinvertebrate metric scores demonstrate a diversity of conditions in both macroinvertebrate community structure and water quality in the Mohawk River in 2014 and 2015 (Table 7). In 2014, total species richness ranged between a low of 10 at Site 5 and high of 31 at Site 22 (Fig. 11a). Overall, species richness was lower in 2015, with values ranging between a low of 7 at Site 4 and high of 26 at Site 7 (Fig. 11b). Species richness was significantly different (p < 0.01) between sample years (Table 8). Downstream, linear trends in species richness, however were not significant in either sample year (Fig. 11). When evaluated by stream reach, mean species richness for 2014 and 2015, combined, was slightly less in the upper stream reaches than in the middle and lower reaches (Fig. 12). These differences, however, were not statistically significant (Table 9). Mean and median species richness were lowest in the upper reaches for samples collected in 2014 and 2015 (Fig. 13). Species richness, however, was not significantly different (p > 0.05) among samples reaches in 2014 or 2015 (Table 8). Similarly, species richness was not significantly different (p > 0.05) between years within each sample reach (Table 10).

EPT richness was significantly different (p < 0.01) between sample years (Table 8), with median EPT richness slightly lower in 2015 than in 2014 (Table 7). In 2014, EPT richness ranged between a minimum of 2 at Sites 3 and 12 and a maximum of 10 at Site 22 (Fig. 14a). In 2015, EPT richness ranged between a minimum of 0 at Site 1 and a maximum of 8 at Sites 8 and 9 (Fig. 14b). Variation in EPT richness was not suggestive of longitudinal changes in stream condition for either sample years (Fig. 14). EPT richness was relatively consistent among the three stream reaches and differences were not significant when study years were combined (p > 0.05) (Fig. 15). Similarly, EPT richness was not significantly different among stream reaches when sample years were evaluated individually (Table 9). In 2014, mean and median EPT richness were relatively constant among the three stream reaches (Fig. 16) and differences were not significant (p > 0.05) (Table 9). In 2015, mean EPT richness was lowest in the lower stream reach compared to the upper and middle reaches (Fig. 16). However, these differences were also not significant (p > 0.05) (Table 9). Similarly, EPT richness was not significantly different (p > 0.05) between years within each sample reach (Table 10).

NCO richness was variable in the Mohawk River in 2014 and 2015, but was relatively similar between sample years (Table 7). Median NCO richness values were 7 and 8 in 2014 and 2015, respectively. In 2014, Site 8 had the lowest NCO richness of any of the sampling locations, while Site 22 had the highest (Fig. 17a); corresponding with the high EPT richness observed for that site (Table 7). In 2015, NCO richness was lowest at Site 1 and highest Sites 7, 9, 10 (Fig. 17b). NCO richness was not significantly different between sample years (p > 0.05) (Table 8). Like the other aforementioned richness metrics, variation in NCO richness was not suggestive of longitudinal changes in stream condition for either sample years (Fig. 17). Changes in NCO richness among stream reaches show a slight downstream decline when sample years are combined (Fig. 18). These trends, however, were not statistically significant (p > 0.08) (Table 9). In 2014, changes in NCO richness were not significantly different (p > 0.05) among stream reaches (Table 9), with mean values ranging between 7 and 8 (Fig. 19). NCO richness was, however, significantly different among stream reaches in 2015 (Table 9), with values showing a distinct linear decline in mean NCO richness from the upper segments to the lower

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segments (Fig. 19). Differences in NCO richness between sample years, by sample reaches, were significantly different (p < 0.05) (Table 10).

Percent dominance of the three most abundance taxa (DOM3) was highly variable among sites in the Mohawk River in 2014 and 2015 (Table 7). Median DOM3 values were substantially greater in 2015 than in 2014, with a value of 89% compared to 57%, respectively. In 2014, DOM3 was lowest at Site 9 and greatest at Site 7 (Fig. 20a). In 2015, DOM3 was lowest at Site 1 and greatest at Site 4 (Fig. 20b). DOM3 was significantly different between sample years (p < 0.001) (Table 8). Though variation in DOM3 displayed a slight longitudinal decrease in 2014 and slight longitudinal increase in 2015, these changes were not significant (Fig. 20). When evaluating spatial trends in DOM3 according to stream reach for 2014 and 2015, collectively, mean DOM3 was slightly lower in the middle stream reaches than in the upper or lower reaches (Fig. 21). These differences, however, were not significant (Table 9). Likewise, DOM3 did not significantly vary (p > 0.05) among stream reaches in either 2014 or 2015 (Table 9). Mean DOM3, however, was comparatively higher for all three stream reaches in 2015 when compared to 2014 (Fig. 22). These differences were also not significant (p > 0.05) (Table 10).

Shannon Diversity (Hʹ) was relatively low for sample locations in the Mohawk River in 2014 and 2015 (Table 7). Median diversity was nearly twice as high in 2014 than in 2015, but maximum values were comparable (Table 7). In 2014, Hʹ was lowest at Site 7 and highest at Site 22 (Fig. 23a). In 2015, Hʹ was lowest at 4 and highest at Site 7 (Fig. 23b). Differences in Hʹ were highly significant between sample years (p < 0.001) (Table 8). Though variation in Hʹ displayed a slight longitudinal increase in 2014 and slight longitudinal decrease in 2015, these changes were not significant (Fig. 23). Collectively, mean Hʹ was higher in middle stream reaches (Fig. 24). However, these differences were not significant (p < 0.05) (Table 9). When evaluated by each sample year, significant differences in Hʹ among stream reaches were not detected (p > 0.05) (Table 9). Mean and median Hʹ were higher in all three stream reaches in 2014 compared to 2015 (Fig. 25). The comparatively higher Hʹ values in 2014 were not statistically significant, however (Table 10).

The Hilsenhoff Biotic Index (HBI) was relatively consistent in the Mohawk River in both 2014 and 2015 (Table 7). Median HBI scores were 6.30 and 7.77 in 2014 and 2015, respectively, and are indicative of moderately impacted stream condition. In 2014, the lowest HBI score (i.e., least impacted) of 5.85 was observed at Site 5 and the highest score (i.e., most impacted) of 7.66 was observed at Site 7 (Fig. 26a). In 2015, the least impacted site, according to the HBI (6.21) was Site 15 and the most impacted site (8.12) was Site 3 (Fig. 26b). Differences in HBI scores between sample years were highly significant (p < 0.001) (Table 8). Variation in HBI scores were relatively static upstream to downstream, and not suggestive of significant changes in stream condition for either sample years (Fig. 26). When evaluated by stream segment for 2014 and 2015 data combined, HBI scores displayed minor variation (Fig. 27). These changes were found to be statistically insignificant, however (Table 9). An evaluation of HBI scores among stream reaches did not yield significant differences (p > 0.05) for 2014 or 2015 data (Table 9). When compared by sample year, mean and median HBI scores were lower in all three stream reaches in 2014 than in 2015 (Fig. 28). Differences in HBI scores were statistically insignificant, however (Table 10).

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Biological Assessment Profile (BAP) scores in 2014 determined water quality in the Mohawk River to range between non-impacted to moderately impacted conditions (Fig. 29a). Six (25%) locations were considered non-impacted, 14 (58%) were slightly impacted, and four (17%) were moderately impacted. In 2014, Site 7 was found to be the most impacted and Site 22 was the least impacted (Fig. 29a). In 2015, BAP scores ranged between slightly and severely impacted, with Site 4 considered the most impacted and Site 7 considered the least impacted (Fig. 29b). No sites were considered non-impacted, with most sites (68%) considered to be moderately impacted. In both 2014 and 2015, there did not appear to be any downstream effects on water quality (Fig. 29). When evaluated by stream reach, mean BAP scores were shown to be highest at sites located in the middle section of the stream reaches (Fig. 30), but trends were not significantly different (p > 0.05) (Table 9). BAP scores did not significantly differ in 2014 among stream reaches, with mean values relatively constant (Table 9). In 2015, however, BAP scores were statistically significant (p < 0.05) among stream reaches, with BAP scores substantially lower in the lower stream reaches. Overall, BAP scores were significantly different between sample years (p < 0.001), but were not significantly different between sample years within stream reaches (Table 10).

c. Spatial trends in water quality & effects on macroinvertebrate community structure

Water quality parameters varied considerably in the Mohawk River throughout the duration of the study, both within (i.e., deployment vs. retrieval) and between years (Table 11). Distinct linear trends in water quality were not evident in 2014 (Fig. 32). In general, temperature, dissolved oxygen, and specific conductivity followed similar patterns sites at the time of multiplate deployment and retrieval (Fig. 32). Notable exceptions were fluctuations in pH levels observed at the most downstream locations (Sites 20-25) and turbidity; which showed not only highly variable spatial differences during both sample deployment and retrieval, but also varied considerably at sites at the time of deployment to at the time of retrieval (Fig. 32). Temporal differences in water quality were significantly different (p > 0.05) for temperature, dissolved oxygen, and pH (Table 12). Conductivity and turbidity levels were not significantly different (p > 0.05) between multiplate deployment and retrieval measurements (Table 12). When evaluated by stream reach, water quality values did not significantly vary for any of the measured parameters at the time of multiplate deployment or retrieval (Table 13). Mean conductivity values were slightly elevated in the middle reaches during both multiplate deployment and retrieval (Fig. 33). Both temperature and dissolved oxygen levels were rather consistent among stream reaches during both multiplate deployment and retrieval, whereas pH and turbidity levels were more variable (Fig. 33).

Similar to 2014 sampling, water quality in the Mohawk River in 2015 was subject to high spatial and temporal variation (Fig. 34). Noticeable deviations in pH and specific conductivity levels at the time of multiplate deployment versus at the time of retrieval were observed for the most downstream locations (~Sites 20-31) (Fig. 34). Turbidity levels were relatively higher at Site 6, Site 12, and Site 13 than other sampling locations during both sample deployment and retrieval (Fig. 34). Temporal differences in water quality were found to be significant (p < 0.05) for dissolved oxygen, specific conductivity, and pH (Table 12). Temporal variations in temperature and turbidity were not significantly different (p > 0.05) between sample deployment and sample retrieval (Table 12). When water quality was evaluated by stream reach, significant differences (p < 0.05) in water quality parameters were not observed for measurements taken at

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the time of multiplate deployment (Table 13). At the time of multiplate retrieval, temperature and specific conductivity levels were found to be significantly difference among stream reaches (Table 13). Specific conductivity levels showed a noticeable downstream decline in mean concentrations from the upper reaches to the lower (Fig. 35). Mean and median turbidity levels were considered generally low for most locations in all three stream reaches; the lower reach, however, had several high turbidity levels at both the time of deployment and retrieval (Fig. 35).

The relationship between macroinvertebrate metrics and water quality parameters varied between sample years (Table 14). HBI scores were found to be significantly correlated (p < 0.05) with dissolved oxygen and specific conductivity levels in 2014. Overall, relationships between macroinvertebrate metric scores and water quality parameters were weak (r < |0.40|) (Table 14). In 2015, temperature was the only water quality parameter significantly correlated with macroinvertebrate metrics. DOM3 and HBI scores were significantly correlated (p < 0.05) with temperature (Table 14).

IV. Discussion

Over the course of the two-year study, multiplates were deployed along a 166-km section of the Mohawk River; approximately 65% of its total length; helping to develop a large-scale spatial understanding of water quality conditions in the Mohawk River on a relatively small temporal scale. Overall trends in community structure were not indicative of compounding, longitudinal changes in stream condition, characteristic of many free-flowing streams and rivers (Vannote et al. 1980). Rather, results from this study showed fluctuations in stream condition largely attributed to negative impacts of channelization and canalization of the Mohawk River on macroinvertebrate community structure. Specifically, results show a relatively un-diverse macroinvertebrate community, dominated by a few, pollution-sensitive taxa. Sensitive taxa, such as Ephemeroptera, Plecoptera, and Trichoptera, were in substantially fewer abundance than more pollution-tolerant organisms. Based on the NYS DEC Biological Assessment Profile (BAP), which uses macroinvertebrate community data to assess water quality using a standardized score that ranges between 0 and 10, average stream condition for the Mohawk River was considered moderately impacted. Stream condition appeared to be less perturbed in 2014 than in 2015.

Six locations in 2014 had BAP assessments of ‘non-impact’; the only six sites in the study to have such a rating. The site with the highest BAP score was Site 22, located just above Lock 7 in the Town of Niskayuna. The macroinvertebrate community at this site had a diversity of Ephemeroptera and Trichoptera taxa, as well as one species of Odonata, which were found only at one other site. In 2014 and 2015 sites just above locks often had comparatively lower macroinvertebrate metric scores, indicating comparatively poorer water quality. One noticeable exception to Site 22 was that, despite being just above a canal lock, it was adjacent to a section of the river heavily infested by the invasive aquatic plant water chestnut (Trapa natans). Though water chestnut is a highly undesirable invasive plant that reduces native plant diversity, impedes watercraft navigation, and creates hypoxic conditions under high densities, this study suggests the submergent, floating-leaved plant may be contributing to the high diversity of pollution-sensitive species at Site 22. Kornijów et al. (2010) found water chestnut beds in the tidal Hudson River to support dense, diverse macroinvertebrate communities despite period of temporary hypoxia. Contrary to their initial hypotheses, they found water chestnut beds to be valuable

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habitats for macroinvertebrate diversity and production. While water chestnut was observed to be prominent in several areas of the Mohawk River, only one other sampling site (Site 30 in 2015) utilized in this study was within similar proximity to dense beds of water chestnut as Site 22. Site 30, though close to a dense water chestnut bed, also had a comparatively highertemperature and specific conductivity level when compared to other sites sampling in 2015. The apparently poorer water quality at this site may have offset potential benefits from the presence of water chestnut.

The remaining five locations to have BAP scores of ‘non-impact’ in 2014 varied spatially, as well as in their position within a stream reach (i.e., upper vs. middle vs. lower). One uniting similarity among these sites, however, was their proximity to tributaries and/or other structures (e.g., islands). Such structures and habitats may offer important, and relatively unique, habitats in an otherwise uniform system. Sedell et al. (1990) noted the potential role of tributaries and habitat downstream of impoundments serving as refugia for aquatic organisms in highly regulated waterbodies. Furthermore, tributaries have the potential increase to biodiversity through downstream drift (Vannote et al. 1980). Ward and Stanford (1995), in attempting to describe the disconnecting effects of impoundments on lotic system, emphasize the importance of lateral connectivity between a river and its floodplain in alleviating some of the deleterious effects of impoundments on riverine habitat and biotic structure.

Only three sites in the Mohawk River were found to have BAP scores considered severely impacted; all of which were sampled in 2015. Two of the sampling sites were directly above canal locks: Site 11, just above of Lock 10 in Amsterdam and Site 14, just above Lock 11 in Amsterdam. Significant trends in measured water quality parameters suggest other water quality issues at these sites are negatively impacting stream condition and macroinvertebrate community structure. The proximity of these sites to the City of Amsterdam could be impacted by anthropogenic sources of pollution, such as those from Combined Sewer Overflows (CSOs). Recent research has identified persistent sources of bacterial pollution caused by failing infrastructure and CSO discharges (the City of Amsterdam has three on the Mohawk River) that could be contributing the noticeably degraded macroinvertebrate community (Brabetz et al. 2017). Both of the sampling sites in this area had HBI scores of approximately 8; indicative of organic pollution, further supporting the hypothesis that the source of degradation is fecal contamination.

Site 26 was the only other site in the study to have a BAP score of ‘severe’, and in fact had the lowest BAP score of any site sampled during the two years. This site was located below Lock 20 in the Town of Marcy. This macroinvertebrate community at this site was dominated by zebra mussels (> 99%). Compared to other sites sampled in 2015, Site 26 also had comparatively lower dissolved oxygen levels at both the time of multiplate deployment and retrieval. More sampling is needed to confirm the impact of dissolved oxygen on macroinvertebrate community structure, but it preliminarily appears to be an important factor limiting macroinvertebrate diversity.

Multiplates were dominated by taxa moderately to highly tolerant of perturbed conditions. In 2014, the dominant taxa on multiplates were Chironomidae; while in 2015, the dominant taxon was the invasive zebra mussel (Dreissena polymorpha). The differences in dominant taxa between years can likely be attributed to seasonal differences. In 2014,

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multiplates were deployed in late August and retrieved early October; whereas they were deployed in mid-July and retrieved in late August in 2015. In the northeast, zebra mussels generally spawn in the spring and summer months, with juveniles remaining up to a month after as free-swimming individuals (Benson et al. 2014). After that, zebra mussels attach to hard substrates and remain relatively stationary for the remainder of their life cycle. The comparatively late deployment period in 2014 likely occurred after, or at the very end, of the zebra mussel’s free-swimming juvenile stage; after the period zebra mussels would be likely attach to new substrates. Larval chironomids, on the other hand, can commonly be collected throughout the sampling season in streams and rivers throughout New York (Bode, 1990). In temperate climates, chironomids may have one to two generations per year, with the larval stage of some species lasting several years (Merritt et al. 2009). Chironomids inhabit a wide range of habitats and water qualities, with some species pollution-sensitive, while others are pollution tolerant. In the Mohawk River, Hilsenhoff Biotic Index (HBI) pollution tolerance scores for chironomids ranged between 4 and 10; on a scale of 0-10, with 10 being considered highly pollution-sensitive. Zebra mussels can similarly withstand a wide range of water quality conditions; though do require sufficient dissolved oxygen concentrations and hard substrates for attachment (Benson et al. 2014). According the HBI, zebra mussels are pollution tolerant, having a HBI score of 8.

The spatially variable assessments of water quality obtained from this study suggest that the canalization on the Mohawk River have fragmented the system in a way that interrupts resource spiraling, prohibits the flow of organisms, and causes significant fluctuations in water quality; violating the assumptions of the River Continuum Concept (Vannote et al. 1980). These results are similar to historical macroinvertebrate studies conducted in the Mohawk River (Simpson 1980, Bode et al. 2004, NYSDEC 2010); and collectively support the Serial Discontinuity Concept (SDC) (Ward and Stanford 1983). The SDC proposes that impoundments cause major disruptions in the longitudinal gradients of resources in lotic systems; causing significant shifts in abiotic and biotic conditions and processes. The extent of the alteration ultimately depends on the location of the impoundment within the system (e.g., low vs. high stream order), the number of impoundments, and connectivity to its floodplain (Ward and Stanford 1995). Ultimately, the SDC predicts that a series of impoundments transition a river from a free-flowing lotic system to a river system more characteristic of a series of alternating lotic and lentic environments.

The modification of lower trophic levels due to river damming can have important implications on overall foodweb structure. Such bottom-up controls could significantly modify higher trophic levels. In the Mohawk River, the series of seasonal and permanently impounded sections of river has resulted in significantly different fish communities, including increased abundance in the permanently impounded sections and markedly different species composition between the reaches (George et al. 2016). In the permanently impounded sections, river conditions were observed to be more lentic in structure and function, resulting in a fish community more characteristic of lentic ecosystems. Researchers found that the amount of drawdown from impoundments was significantly correlated with fish community structure, explaining 55% of the variation. The effects of benthic community structure on overall fish communities in the Mohawk River are currently unknown. Benthic macroinvertebrates, however, have been shown to be an incredibly important prey item for one species of migratory fish in the Mohawk River. Simonin et al. (2007) found that adult blueback herring fed predominantly on

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benthic macroinvertebrates in the Mohawk River. The reliance of this vitally important trophic link on migratory fish such as blueback herring, a species that has been negatively impacted by river modifications in the Hudson-Mohawk basin (Simonin et al. 2007), is a critical consideration when developing effective restoration and management strategies for the Mohawk River.

V. Conclusions & Recommendations

The seemingly lack of spatial trends in macroinvertebrate community structure in the Mohawk River highlight the challenges faced by resource managers in trying to develop comprehensive restoration strategies for the Mohawk River Watershed. Changes in land use, industrial pollution, nonpoint source runoff, and stormwater management in the watershed have compounded the effects caused by the canalization of the Mohawk River. During this study, these effects were most evident in the area around Amsterdam. Despite relatively discrete water quality conditions throughout the study area, the results of this study do demonstrate the importance of habitat diversity and refugia on improving macroinvertebrate community structure and water quality in the Mohawk River. Specifically, aquatic vegetation and tributary inflow may be important drivers of macroinvertebrate diversity and help maintain comparatively healthier water quality. The effect of tributary connectivity on benthic community structure in the Mohawk River mainstem warrants further investigation. Likewise, evaluating the effect of lower trophic structure on fish community structure could provide information vital to understanding system-wide ecological integrity; helping to guide restoration and management strategies in the Mohawk River Watershed that effectively and successfully integrate human-based needs (e.g., navigation, recreation, drinking and wastewater management, etc.) while improving and sustaining the health of the ecosystem.

VI. Acknowledgments

Funding for this project was provided by the SUNY College of Enivronmental Science and Forestry through a grant from the NYSDEC. A tremendous thank you goes out to the staff at NYSDEC Region 4, notably Mr. Scott Wells, who without which, we would not have been able to successfully navigate the Mohawk River. We thank Watershed Assessment Associates for their technical expertise and identification of the 2015 macroinvertebrate samples. We would also like to thank the NYSDEC PEERS Program for their guidance and support in 2015.

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VII. Literature Cited

Benson AJ, Raikow D, Larson J, Fusaro A, Bogdanoff AK. 2017. Dreissena polymorpha [Internet]. Gainesville (FL): USGS Nonindigenous Aquatic Species Database; [cited 2017 Apr 28]. Available from: https://nas.er.usgs.gov/queries/factsheet.aspx?speciesid=5 Revision Date: 6/26/2014.

Bode RW, Novak MA, Abele LE, Heitzman DL, Smith AJ. 2004. 30 Year trends in water quality of rivers and streams in New York State: based on macroinvertebrate data 1972-2002. [Internet]. Albany (NY): NYSDEC, Division of Water; [cited 2017 Mar 23]. Available from: www.dec.ny.gov.

Brabetz BL, Law NA, Rachford J, Epstein J, Lipscomb J, Shapley D. 2017. The leak, the rain, and the river: what we learned about CSOs, run-off, and the Mohawk River’s water quality in 2016. Proceedings of the 2017 Mohawk River Symposium; Schenectady, NY.

Camargo JA, Alonso A, De La Puente M. 2004. Multimetric assessment of nutrient enrichment in impounded rivers based on benthic macroinvertebrates. Environ. Monitor. Assess. 96:233-249.

Ellis LE, Jones NE. 2013. Longitudinal trends in regulated rivers: a review and synthesis within the context of the serial discontinuity concept. Environ. Rev. 21:136-148.

George SD, Baldigo BP, Wells SM. 2016. Effects of seasonal drawdowns on fish assemblages in sections of an impounded river-canal system in upstate New York. Trans. Amer. Fish. Soc. 145:1348-1357.

Grubbs SA, Taylor JM. 2004. The influence of flow impoundment and river regulation on the distribution of riverine macroinvertebrates at Mammoth Cave Nation Park, Kentucky, USA. Hydrobiologia 520:19-28.

Harrell Jr FE. 2016. Hmisc: Harrell Miscellaneous. R Foundation for Statistical Computing; R package version 4.0-2. Available from: https://CRAN.R-project.org/package=Hmisc

Hislop C. 1948. The Mohawk, Rivers of America. New York (NY): Rinehart & Company 355+pp.

Holt CR, Pfitzer D, Scalley C, Caldwell BA, Batzer DP. 2015. Macroinvertebrate community responses to annual flow variation from river regulation: an 11-year study. River Research and Applications 31:798-807.

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Johnson, SL, NH Ringler. 2014. The response of fish and macroinvertebrate assemblages to multiple stressors: A comparative analysis of aquatic communities in a perturbed watershed (Onondaga Lake, NY). Ecol. Indic. 41:198-208.

Kornijów R, Strayer DL, Caraco NF. 2010. Macroinvertebrate communities of hypoxic habitats created by an invasive plant (Trapa natans) in the freshwater tidal Hudson River. Fundam. Appl. Limnol., Arch. Hydrobiol. 176:199-207

Larinier M. 2001. Environmental issues, dams and fish migration. In: Marmulla G, editor. Dams, fish and fisheries: opportunities, challenges and conflict resolution. Rome (Italy): Food and Agricultural Organization of the United Nations, Technical paper No. 419. P. 45-90

McBride ND. 1987. Interim management plan for Mohawk River fisheries [Internet]. Stamford (NY): New York State Department of Environmental Conservation; [cited 2017 Mar 23]. Available from: www.dec.ny.gov.

McBride ND. 2009. Lower Mohawk River Fisheries. Paper presented at: Proceedings from the 2009 Mohawk River Watershed; Schenectady, NY.

Merritt RW, Cummins KW, Berg MB. 2009. An Introduction to the Aquatic Insects of North America. Debuque (IA): Kendall/Hunt Publishing Company 1214 p.

[NYSDEC] New York State Department of Environmental Conservation. 2010. The Mohawk River Basin waterbody inventory and priority waterbodies list [Internet]. Albany (NY): NYSDEC Bureau of Watershed Assessment and Management, Division of Water; [cited 2017 Mar 23]. Available from: www.dec.ny.gov.

[NYSDEC] New York State Department of Environmental Conservation. 2012. Mohawk River Basin action agenda 2012-2016 [Internet]. Albany (NY): NYSDEC Mohawk River Basin Program; [cited 2017 Mar 13]. Available from www.dec.ny.gov.

Olden JD, Naiman RJ. 2010. Incorporating thermal regimes into environmental flows assessments: modifying dam operations to restore freshwater ecosystem integrity. Freshw. Biol. 55:86-107.

R Core Team. 2017. R: A language and environment for statistical computing [Internet]. Vienna (Austria). R Foundation for Statistical Computing; [cited 2017 Apr 28]. Available from: www.R-project.org.

Sedell JR, Reeves GH, Hauer FR, Stanford JA, Hawkins CP. 1990. Role of refugia in recovery from disturbances: modern fragmented and disconnected river systems. Environ. Manag. 14:711-724.

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Simpson KW. 1980. Macroinvertebrate survey of the Mohawk River-Barge Canal system, 1972 (environmental health report). NYS Department of Health, Environmental Health Institute, Division of Laboratories and Research. 43 pp.

Smith AJ, Duffy BT, Heitzman DL. 2010. Mohawk River (Utica) biological assessment: 2009 survey [Internet]. Albany (NY): New York State Department of Environmental Conservation; [cited 2017 Mar 23]. Available from: www.dec.ny.gov.

Smith AJ. 2016. Standard operating procedures: biological monitoring of surface waters in New York State [Internet]. Albany (NY): New York State Department of Environmental Conservation, Division of Water; [cited 2017 Mar 23]. Available from: www.dec.ny.gov.

Simonin PW, Limburg KE, Machut LS. 2007. Bridging the energy gap: anadromous blueback herring feeding in the Hudson and Mohawk Rivers, New York. Trans. Amer. Fish. Soc. 136:1614-1621

Vannote RL, Minshall GW, Cummins KW, Sedell JR, Cushing CE. 1980. The river continuum concept. Canadian Journal of Fisheries and Aquatic Science 37:130-136.

Ward JV, Stanford JA. 1983. The serial discontinuity concept of lotic ecosystems. In: Dynamics of lotic ecosystems. Edited by: TD Fontaine and SM Bartell. Ann Arbor Scientific Publishers, Ann Arbor, MI pp. 29-42.

Ward JV, Stanford JA. 1995. The serial discontinuity concept: extending the model to floodplain rivers. Regul. River. 10:159-168.

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Table 1. List of multiplate sampling sites in the Mohawk River in 2014.

DS Order/yr Site Description Reach NYTM E NYTM N

1 Lock 18 Pool Upper 490995 4768578 2 Lock 18 Pool Middle 495830 4764044 3 Lock 18 Pool Middle 498314 4762615 4 Lock 18 Pool Lower 505853 4762691 5 Lock 15 Pool Upper 523868 4760089 6 Lock 15 Pool Middle 529527 4756936 7 Lock 15 Pool Lower 530428 4755412 8 Lock 14 Pool Upper 531023 4753905 9 Lock 14 Pool Lower 534289 4750623

10 Lock 14 Pool Middle 532016 4751929 11 Lock 12 Pool Upper 545386 4752084 12 Lock 12 Pool Lower 556236 4753518 13 Lock 12 Pool Lower 557604 4754711 14 Lock 9 Pool Upper 570382 4752001 15 Lock 9 Pool Middle 573578 4750739 16 Lock 9 Pool Lower 577948 4747890 17 Lock 8 Pool Upper 578524 4747641 18 Lock 8 Pool Middle 581284 4744539 19 Lock 7 Pool Middle 590327 4744934 20 Lock 7 Pool Middle 591567 4744476 21 Lock 7 Pool Lower 593579 4741239 22 Lock 7 Pool Lower 593975 4740103 23 Crescent Lake Lower 603353 4741481 24 Crescent Lake Lower 604819 4740404 25 Crescent Lake Lower 604937 4740481

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Table 2. List of multiplate sampling sites in the Mohawk River in 2015.

DS Order/yr Site Description Reach NYTM E NYTM N

1 Lock 20 Pool Lower 474042 4779094 2 Lock 20 Pool Lower 472625 4780694 3 Lock 20 Pool Lower 475981 4777058 4 Lock 19 Pool Lower 476744 4776326 5 Lock 19 Pool Lower 482714 4773077 6 Lock 19 Pool Lower 490422 4769388 7 Lock 17 Pool Upper 507287 4762591 8 Lock 17 Pool Middle 509891 4763693 9 Lock 17 Pool Lower 511954 4765235

10 Lock 16 Pool Upper 512720 4765056 11 Lock 16 Pool Middle 515443 4763998 12 Lock 16 Pool Middle 518444 4761970 13 Lock 16 Pool Lower 521175 4760561 14 Lock 15 Pool Upper 526121 4760207 15 Lock 14 Pool Upper 534654 4750885 16 Lock 14 Pool Middle 539788 4749226 17 Lock 14 Pool Lower 544629 4751404 18 Lock 11 Pool Upper 564543 4754866 19 Lock 11 Pool Middle 567423 4752667 20 Lock 11 Pool Lower 569758 4752105 21 Lock 10 Pool Upper 558347 4755199 22 Lock 10 Pool Middle 561078 4755831 23 Lock 10 Pool Lower 563992 4755641 24 Lock 7 Pool Upper 582643 4742233 25 Lock 7 Pool Upper 584257 4741106 26 Lock 7 Pool Upper 585774 4741159 27 Lock 7 Pool Upper 586997 4742206 28 Crescent Lake Upper 594615 4739742 29 Crescent Lake Upper 596002 4737619 30 Crescent Lake Upper 598215 4736973 31 Crescent Lake Upper 598950 4737980

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Table 3. Descriptions of macroinvertebrate metrics used for multiplate data collected from the Mohawk River (2014-2015). Metric Source Description

Taxa Richness (RICH) N/A Total number of taxa(Genus/species) collected in a sample. Higher richness values are associated with good water quality.

Shannon Diversity (H´) Shannon and Weaver (1949)

Takes into account species richness (# of species) and evenness (# of individuals in each species):

∑ ln Where: pi = percentage of species i in the sample; k = species

Ephemeroptera-Plecoptera-Trichoptera richness (EPT)

Lenat (1988) Total number of Ephemeroptera, Plecoptera, and Trichoptera taxa found in the subsample. EPT taxa are pollution intolerant species and are often associated with good water quality.

Non-Chironomidae & Oligochaeta richness (NCO)

Smith (2016) Taxa richness, excluding taxa belonging to the Chironomidae & Oligochaeta groups. NCO taxa are considered to be pollution-sensitive taxa, while Chironomidae & Oligochaeta are often the most abundant taxa in impacted systems. NCO richness is used for sandy streams and is comparable to EPT richness.

% Dominance of top 3 taxa (DOM3)

Smith (2016) Combined percent contribution of the three most dominant species.

Hilsenhoff Biotic Index (HBI)

Hilsenhoff (1987) Measures organic (sewage) pollution effects. Values range from 0 (pristine) to 10 (polluted).

Biological Assessment Profile (BAP)

Smith (2016) The BAP incorporates the metrics RICH, Hʹ, EPT, and HBI and converts them to a common scale. Values range from 0 (severely impacted) to 10 (non-impacted).

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Table 4. Taxonomic groups developed for Analysis of Variance.

Group Group Code Year IncludesEphemeroptera-Plecoptera-Trichoptera

EPT 2014, 2015 All EPT species

Chironomidae CHIR 2014, 2015 All Chironomidae species

Arthropoda ARTH 2014, 2015 Amphipoda Isopoda Hydrachnidia

Mollusca MOLL 2014, 2015 GastropodaBivalvia

Annelida ANN 2014 Oligochaeta Hirudinea

Zooplankton ZOO 2014 Cladocera Copepoda

Odonata-Coleoptera-Diptera OCD 2014, 2015 All OCD species, excludingChironomidae (Diptera)

Coelenterata COEL 2015 Hydra sp.

Protostomia PROT 2015 Nemertea Oligochaeta Platyhelminthes

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Table 5. Analysis of Variance of macroinvertebrate community composition for stream reaches in the Mohawk River, by major taxonomic groups. Significant differences (p < 0.05) are denoted in bold.

DF SUM SQ MEAN SQ F VALUE PR(>F) 2014

EPT 2 1892.60 946.31 1.63 0.22

CHIR 2 4507.00 2253.60 0.31 0.74

ARTH 2 753.00 376.51 1.69 0.21

MOLL 2 567.20 283.60 1.41 0.27

ANN 2 362.60 181.31 0.54 0.59

ZOO 2 570.10 285.04 0.44 0.65

OCD 2 17.55 8.77 2.01 0.16

2015 EPT 2 152.50 76.27 0.56 0.58

MOLL 2 855191.00 427596.00 0.80 0.46

ARTH 2 757.20 378.62 1.30 0.29

COEL 2 14.14 7.07 0.59 0.56

PROT 2 172708.00 86354.00 2.30 0.12

OCD 2 0.34 0.17 0.19 0.83

CHIR 2 46665.00 23332.00 1.99 0.16

Table 6. Analysis of Variance of functional feeding group composition for stream reaches in the Mohawk River. Significant differences (p < 0.05) are denoted in bold.

RESPONSE DF SUM SQ MEAN SQ F VALUE PR(>F) 2014

CF 2 846.60 423.31 0.53 0.60CG 2 369.20 184.61 0.14 0.87

PRD 2 811.40 405.71 1.66 0.21SCR 2 1987.10 993.56 1.98 0.16 SHR 2 676.80 338.42 0.28 0.76

2015 CF 2 1213783.00 606891.00 1.19 0.32 CG 2 16317.00 8158.40 0.28 0.76

PRD 2 85.37 42.69 0.67 0.52SCR 2 676.23 338.11 4.27 0.03 SHR 2 3006.90 1503.47 1.75 0.19

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Table 7. Summary of macroinvertebrate metric results for multiplate samples collected from the Mohawk River in 2014 and 2015. Refer to Table 3 for metric descriptions.

METRIC MINIMUM MEDIAN MAXIMUM MEAN STD.

DEVIATIONYEAR 2014 2015 2014 2015 2014 2015 2014 2015 2014 2015

SPP. RICHNESS 10.00 7.00 20.00 15.00 31.00 26.00 19.83 15.32 4.98 7.00

EPT RICHNESS 2.00 0.00 4.00 2.00 10.00 8.00 4.67 3.03 1.86 0.00

NCO RICHNESS 3.00 3.00 7.00 8.00 14.00 13.00 7.79 8.29 2.48 3.00

DOM-3 37.50 51.17 56.91 88.58 90.34 99.72 58.05 83.66 14.18 51.17

DIVERSITY (Hʹ) 0.79 0.04 2.36 1.30 2.75 2.44 2.25 1.29 0.46 0.04

HBI 5.85 6.21 6.30 7.77 7.66 8.12 6.45 7.56 0.49 6.21

BAP 4.00 0.38 6.41 3.72 8.93 7.48 6.41 3.95 1.32 0.38

Table 8. ANOVA of macroinvertebrate metric scores between sample years (2014 & 2015) for multiplate samples collected from the Mohawk River. Significant differences are denoted in bold.

METRIC DF SUM SQ MEAN SQ F VALUE PR(>F)RICH 1 275.24 275.24 13.79 <0.001EPT 1 36.14 36.14 9.86 <0.05NCO 1 3.36 3.36 0.54 0.47DOM3 1 8871.60 8871.60 43.30 <0.001H' 1 12.388 1 2.39 35.18 <0.001HBI 1 33.12 33.12 86.40 <0.001BAP 1 81.53 81.53 37.97 <0.001

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Table 9. ANOVA of macroinvertebrate metric scores by stream reach (upper, middle, lower) for multiplate samples collected from the Mohawk River. Sample years were evaluated individually and collectively. Significant differences are denoted in bold.

STREAM REACH METRIC DF SUM SQ MEAN SQ F VALUE PR(>F)

2014

RICH 2 82.50 41.25 1.78 0.19EPT 2 0.35 0.18 0.05 0.95NCO 2 7.65 3.82 0.60 0.56DOM3 2 199.90 99.98 0.47 0.63H' 2 0.30 0.15 0.71 0.50HBI 2 0.28 0.14 0.56 0.58BAP 2 0.18 0.09 0.05 0.95

2015

RICH 2 78.14 39.07 2.66 0.09EPT 2 15.80 7.90 2.23 0.13NCO 2 56.73 28.37 5.94 0.01DOM3 2 1088.40 544.21 2.96 0.07H' 2 2.58 1.29 3.19 0.06HBI 2 1.32 0.66 2.88 0.07BAP 2 18.40 9.20 4.64 0.02

2014+2015

RICH 2 80.62 40.31 1.67 0.20EPT 2 5.60 2.80 0.65 0.53NCO 2 30.48 15.24 2.60 0.08DOM3 2 1055.20 527.62 1.47 0.24H' 2 2.06 1.03 1.84 0.17HBI 2 3.16 1.58 1.64 0.20BAP 2 7.58 3.79 1.05 0.36

Table 10. ANOVA of macroinvertebrate metric scores between years within stream reaches (upper, middle, lower) for multiplate samples collected from the Mohawk River. Significant differences are denoted in bold.

METRIC SUM SQ MEAN SQ F VALUE PR(>F)RICH 113.02 56.51 3.09 0.05EPT 8.87 4.43 1.22 0.30

NCO 36.21 18.11 3.31 0.04DOM3 400.30 200.20 1.02 0.37

H' 0.93 0.46 1.44 0.25

HBI 0.10 0.05 0.15 0.86

BAP 9.24 4.62 2.38 0.10

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Table 11. Summary of water quality results for multiplate sampling locations in the Mohawk River in 2014 and 2015. Summary statistics at the time of multiplate deployment and retrieval are shown.

PARAMETER MINIMUM MEDIAN MAXIMUM MEAN STD.

DEVIATION DEPLOYMENT/RETRIEVAL1 YEAR D R D R D R D R D R

TEMPERATURE (°C) 2014 20.80 17.21 21.90 18.44 23.90 19.68 21.98 18.38 0.77 0.63

2015 20.71 21.17 24.08 24.18 25.92 26.77 23.68 24.09 1.32 1.75

DISSOLVED OXYGEN (MG/L) 2014 7.00 7.37 8.70 9.62 10.70 11.09 8.67 9.53 0.90 0.78

2015 219 236 283 341 355 397 286.29 328.45 31.25 45.97

PH 2014 7.30 7.43 7.60 7.65 7.90 8.05 7.57 7.67 0.15 0.14

2015 7.42 7.45 7.67 7.82 8.05 8.54 7.71 7.88 0.18 0.33

SPECIFIC CONDUCTIVITY (µS/CM) 2014 260 232 309 316 499 583 324.28 338.24 63.55 85.73

2015 7.34 6.34 8.8 8.36 10.32 10.72 8.84 8.37 0.75 1.03

TURBIDITY (NTU) 2014 1.20 1.10 6.10 3.30 76.10 21.50 13.40 7.28 17.75 7.37

2015 1.4 1 3.4 2.4 15.1 42 4.51 4.88 3.36 8.42 1D = deployment; R = retrieval

Table 12. ANOVA of water quality parameters between multiplate deployment and retrieval. Significant differences are denoted in bold.

YEAR PARAMETER DF SUM SQ MEAN SQ F VALUE PR(>F)

2014

Temperature 1 153.33 153.33 297.59 <0.001Dissolved oxygen 1 9.24 9.24 13.10 <0.001pH 1 2776.00 2775.50 0.47 0.50

Specific conductivity 1 0.13 0.13 6.12 0.02Turbidity 1 465.00 465.01 2.44 0.13

2015

Temperature 1 2.65 2.65 1.10 0.30

Dissolved oxygen 1 3.43 3.43 4.19 0.05pH 1 27552.00 27552.40 17.83 <0.001Specific conductivity 1 0.49 0.49 7.01 0.01Turbidity 1 2.13 2.13 0.05 0.82

27  

Table 13. ANOVA of water quality parameters among stream reaches during multiplate deployment and retrieval for each sample year. Significant differences are denoted in bold.

YEAR PARAMETER D/R1 DF SUM SQ MEAN SQ F VALUE PR(>F)

2014

Temperature D 2 0.31 0.16 0.24 0.79R 2 0.50 0.25 0.58 0.57

Dissolved oxygen D 2 1.31 0.66 0.81 0.46R 2 1.41 0.71 1.16 0.33

Specific conductivity D 2 9174.00 4587.10 1.10 0.35R 2 16774.00 8387.20 1.10 0.35

pH D 2 0.09 0.05 2.25 0.13R 2 0.05 0.02 1.36 0.28

Turbidity D 2 541.40 270.70 0.818 0.45R 2 310.50 155.25 3.39 0.05

2015

Temperature D 2 1.09 0.54 0.30 0.74R 2 20.87 10.43 4.11 0.03

Dissolved oxygen D 2 0.84 0.42 0.73 0.49R 2 0.48 0.24 0.21 0.81

Specific conductivity D 2 306.00 152.99 0.15 0.86R 2 23320.00 11660.00 8.15 <0.05

pH D 2 0.16 0.08 2.7095 0.08R 2 0.34 0.17 1.63 0.21

Turbidity D 2 8.58 4.29 0.36 0.70R 2 267.90 133.95 2.02 0.15

1D = deployment; R = retrieval

28

Table 14. Spearman rank correlation analysis of macroinvertebrate metrics and water quality parameters. P-values are shown in parentheses. Significant relationships are denoted in bold.

YEAR METRIC/

PARAMETER1 TEMP DO PH COND TURB

2014

RICH 0.17 0.14 -0.02 -0.03 -0.23

(0.43) (0.53) (0.91) (0.89) (0.28)

NCO 0.04 -0.14 -0.20 0.26 -0.02

(0.85) (0.52) (0.36) (0.22) (0.91)

EPT -0.11 0.08 -0.14 -0.23 0.02

(0.61) (0.72) (0.50) (0.29) (0.91)

Hʹ 0.23 0.20 0.15 -0.02 -0.09

(0.28) (0.34) (0.49) (0.92) (0.69)

DOM3 -0.17 -0.27 -0.21 0.22 0.14

0.42 0.19 0.32 0.31 0.52

HBI -0.03 -0.46 -0.36 0.49 0.22

(0.89) (0.02) (0.08) (0.02) (0.30)

BAP -0.01 0.21 0.04 -0.24 -0.04

(0.96) (0.33) (0.85) (0.25) (0.87)

2015

RICH -0.34 -0.05 -0.07 -0.21 0.07

(0.06) (0.78) (0.69) (0.25) (0.70)

NCO -0.16 0.07 -0.13 -0.19 -0.10

(0.39) (0.70) (0.49) (0.31) (0.61)

EPT -0.23 -0.03 -0.28 -0.20 -0.28

(0.21) (0.86) (0.12) (0.27) (0.12)

Hʹ -0.33 -0.07 -0.14 -0.24 0.04

(0.07) (0.71) (0.47) (0.19) (0.85)

DOM3 0.42 0.17 0.15 0.20 -0.08

(0.02) (0.36) (0.42) (0.28) (0.66)

HBI 0.39 0.18 0.17 0.20 -0.04

(0.03) (0.34) (0.35) (0.28) (0.83)

BAP -0.34 -0.04 -0.17 -0.21 -0.05

(0.06) (0.85) (0.35) (0.25) (0.78) 1TEMP = temperature; DO = dissolved oxygen; COND = specific conductivity; TURB = turbidity.

29

Figure 1. Macroinvertebrate multiplate sampling locations in the Mohawk River in 2014.

30

Figure 2. Macroinvertebrate multiplate sampling locations in the Mohawk River in 2015.

31

Figure 3. Depiction of multiplate devices constructed and used for this study. Figure obtained from Smith 2016.

32

Figure 4. Schematic depicting stream reach designations. Distances between canal locks varied in length and site designations were approximate and based on visual assessments.

Lock 20

Lock 19

Upper

Middle

Lower

33

Figure 5. Total macroinvertebrate abundances, by major taxonomic groups, for multiplates retrieved from the Mohawk River in (a) 2014 (N=24) and (b) 2015 (N=31). Refer to Table 4 for group definitions.

11.4%

66.5%

7.1%

4.3%

6.6%

3.3% 0.9%

EPT Chironomid Arthropod Mollusca Annelida Zooplankton OCD

1.51%

71.26%

1.46%

0.08%

10.52%

0.05%

15.13%

EPT Mollusca Arthropod Coelenterata Protostomia OCD Chrionomid

(a) 

(b) 

34

Figure 6. Percent contributions of macroinvertebrates, by major taxonomic groups, at sampling locations in the Mohawk River in (a) 2014 and (b) 2015. Locations are arranged in downstream order left to right. Refer to Table 4 for group definitions.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Site

EPT Chironomid Arthropod Mollusca Annelida Zooplankton OCD

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Site

EPT Mollusca Arthropod Coelenterata Protostomia OCD Chrionomid

(a) 

(b) 

35  

Figure 7. Box plots of macroinvertebrate abundances, by stream segment in the Mohawk River in (a) 2014 and (b) 2015. Segments are arranged in downstream order. Refer to Table 4 for group definitions.

(a) 

(b) 

36

Figure 8. Macroinvertebrate abundances according to Functional Feeding Group (FFG) for multiplates retrieved from the Mohawk River in (a) 2014 and (b) 2015.

14%

42%

14%

11%

19%

78%

15%

1% 1%

5%

CF CG PRD SCR SHR

(a) 

(b) 

37

Figure 9. Percent contributions of macroinvertebrates, by Functional Feeding Groups, at sampling locations in the Mohawk River in (a) 2014 and (b) 2015. Locations are arranged in downstream order left to right.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Site

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Site

CF CG PRD SCR SHR

(a) 

(b) 

38

Figure 10. Box plots of Functional Feeding Group abundances, by stream segment in the Mohawk River in (a) 2014 and (b) 2015. Segments are arranged in downstream order.

(a) 

(b) 

39  

Figure 11. Species richness of macroinvertebrate communities collected from multiplates deployed in the Mohawk River in (a) 2014 and (b).

y = 0.207x + 17.246R² = 0.0865

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Species Richness

y = ‐0.0609x + 16.297R² = 0.0188

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Species Richness

Site

(b) 

(a) 

40

Figure 12. Species richness of macroinvertebrate communities in the Mohawk River, by stream reach for 2014 and 2015.

Figure 13. Species richness of macroinvertebrate communities in the Mohawk River, by stream reach and year.

41

Figure 14. EPT richness of macroinvertebrate communities collected from multiplates deployed in the Mohawk River in (a) 2014 and (b).

y = 0.0165x + 4.4601R² = 0.004

0

2

4

6

8

10

12

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

EPT Richness

y = 0.0044x + 2.9613R² = 0.0004

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

EPT Richness

Site

(a) 

(b) 

42  

Figure 15. EPT richness of macroinvertebrate communities in the Mohawk River, by stream reach for 2014 and 2015.

Figure 16. EPT richness of macroinvertebrate communities in the Mohawk River, by stream reach and year.

43  

Figure 17. NCO richness of macroinvertebrate communities collected from multiplates deployed in the Mohawk River in (a) 2014 and (b).

y = ‐0.0039x + 7.8406R² = 0.0001

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

NCO Richness

y = 0.0165x + 8.0258R² = 0.0036

0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

NCO Richness

Site

(b) 

(a) 

44  

Figure 18. NCO richness of macroinvertebrate communities in the Mohawk River, by stream reach for 2014 and 2015.

Figure 19. NCO richness of macroinvertebrate communities in the Mohawk River, by stream reach and year.

45

Figure 20. Percent dominance (DOM3) of macroinvertebrate communities collected from multiplates deployed in the Mohawk River in (a) 2014 and (b).

y = ‐0.4536x + 63.724R² = 0.0512

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

DOM3 (%)

y = 0.2553x + 79.578R² = 0.0259

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

DOM3 (%)

Site

(b) 

(a) 

46

Figure 21. Percent dominance (DOM3) of macroinvertebrate communities in the Mohawk River, by stream reach for 2014 and 2015.

Figure 22. Percent dominance (DOM3) of macroinvertebrate communities in the Mohawk River, by stream reach and year.

47  

Figure 23. Shannon diversity (Hʹ) of macroinvertebrate communities collected from multiplates deployed in the Mohawk River in (a) 2014 and (b).

y = 0.0124x + 2.0926R² = 0.0369

0.00

0.50

1.00

1.50

2.00

2.50

3.00

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Diversity (H')

y = ‐0.0046x + 1.3649R² = 0.0038

0.00

0.50

1.00

1.50

2.00

2.50

3.00

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Diversity (H')

Site

(b) 

(a) 

48

Figure 24. Shannon diversity (Hʹ) of macroinvertebrate communities in the Mohawk River, by stream reach for 2014 and 2015.

Figure 25. Shannon diversity (Hʹ) of macroinvertebrate communities in the Mohawk River, by stream reach and year.

49

Figure 26. HBI scores of macroinvertebrate communities collected from multiplates deployed in the Mohawk River in (a) 2014 and (b).

y = ‐0.0264x + 6.7829R² = 0.1429

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

HBI Score

y = 0.0087x + 7.4233R² = 0.0242

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

HBI Score

Site

(b) 

(a) 

50  

Figure 27. HBI scores of macroinvertebrate communities in the Mohawk River, by stream reach for 2014 and 2015. Note the y-axis scale.

Figure 28. HBI Scores of macroinvertebrate communities in the Mohawk River, by stream reach and year. Note the y-axis scale.

51  

 Figure 29. Biological assessment profile scores for macroinvertebrates collected in the Mohawk River in (a) 2014 and (b) 2015.

y = 0.022x + 6.1322R² = 0.0139

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Non

Slight

Moderate

Severe

y = ‐0.0091x + 4.0979R² = 0.0028

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Site

Non

Slight

Moderate

Severe

(a) 

(b) 

52

Figure 30. BAP scores of macroinvertebrate communities in the Mohawk River, by stream reach for 2014 and 2015.

Figure 31. BAP scores of macroinvertebrate communities in the Mohawk River, by stream reach and year.

53

0

2

4

6

8

10

12

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Dissolved

 oxygen (mg/L)

Deployment Retrieval

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Specific conductivity (µS/cm

)Site

Deployment Retrieval

6.8

7

7.2

7.4

7.6

7.8

8

8.2

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

pH

Deployment Retrieval

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Temperature (°C)

Deployment Retrieval

0

10

20

30

40

50

60

70

80

1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25

Turbidity (NTU

)

Site

Deployment Retrieval Figure 32. Spatial trends in water quality parameters at multiplate sampling locations in the Mohawk River in 2014. Results at the time of multiplate deployment (Aug 26th and 27th) and retrieval (Sept 30-Oct 2) are displayed.

54  

Figure 33. Spatial trends in water quality parameters at multiplate sampling locations in the Mohawk River in 2014, by stream reach. Results at the time of multiplate deployment (D; Aug 26th and 27th) and retrieval (R; Sept 30-Oct 2) are displayed.

55

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031

Temperature (°C)

Deployment Retrieval

0

2

4

6

8

10

12

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Deployment Retrieval

6.8

7

7.2

7.4

7.6

7.8

8

8.2

8.4

8.6

8.8

1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031

pH

Deployment Retrieval

0

50

100

150

200

250

300

350

400

450

1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031

Specific conductivity (µS/cm

)

Site

Deployment Retrieval

0

5

10

15

20

25

30

35

40

45

1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031

Turbidity (NTU

)

Site

Deployment Retrieval

Figure 34. Spatial trends in water quality parameters at multiplate sampling locations in the Mohawk River in 2015. Results at the time of multiplate deployment (July 16th & 17th) and retrieval (Aug 26-28) are displayed.

56  

  

 

Figure 35. Spatial trends in water quality parameters at multiplate sampling locations in the Mohawk River in 2015, by stream reach. Results at the time of multiplate deployment (D; July 16th & 17th) and retrieval (R; Aug 26-28) are displayed.

57

Attachment A: Benthic macroinvertebrate species list for multiplate samples collected from the Mohawk River in 2014 and 2015

Coelenterata Hydridae

Hydra sp. Nemertea

Hoplonemertea Prostoma graecense

Platyhelminthes Planariidae

Undetermined Turbellaria Annelida

Oligochaeta Tubificida

Tubificidae Undetermined Tubificidae

Naididae Bratislavia unidentata Nais sp. Ripistes parasita Stylaria lacustris

Annelida Hirudinea

Rhynchobdellida Glossiphoniidae

Undetermined Glossiphoniidae Undetermined Hirudinea

Mollusca Gastropoda

Physidae Physella sp.

Lymnaeidae Stagnicola sp.

Planorbidae Gyralus Laevapex fuscus

Ancylidae Ferrissia sp. Undetermined Ancylidae

Pleuroceridae Undetermined Pleuroceridae

Bithyniidae Bithynia tentaculata

 

58  

Hydrobiidae Undetermined Hydrobiidae

Valvatidae Valvata piscinalis Valvata sp.

Pelecypoda Veneroidea

Dreissenidae Dreissena polymorpha

Arthropoda Crustacea Branchiopoda

Cladocera Undetermined Cladocera

Maxillopoda Copepoda Undetermined Copepoda

Isopoda Asellidae

Caecidotea sp. Amphipoda

Gammaridae Gammarus sp.

Undetermine Gammaridae Arachnoidea

Unioncolidae Undetermined Acariformes

Arthropoda Insecta

Ephemeroptera Isonychiidae

Isonychia sp. Baetidae

Baetis intercalaris Baetis sp. Procloeon sp. Undetermined Baetidae Heptageniidae

Epeorus sp. Maccaffertium mediopunctatum Maccaffertium terminatum

Maccaffertium sp. Stenacron interpunctatum

Stenacron sp.

 

59  

Stenonema Stenonema femoratum

Undetermined Heptageniidae Undetermined Heptageniidae Leptophlebiidae

Undetermined Leptophlebiidae Leptohyphidae

Tricorythodes sp. Caenis sp.

Undetermined Ephemeroptera Odonata

Coenagrionidae Enallagma sp.

Plecoptera Perlidae

Acroneuria abnormis Agnetina sp. Neoperla sp.

Coleoptera Gyrinidae

Dineutus sp. Elmidae

Stenelmis sp. Trichoptera

Psychomyiidae Psychomyia flavida Psychomyia sp.

Polycentropodinae Cyrnellus fraternus Crynellus sp.

Neureclipsis sp. Polycentropus sp. Undetermined Polycentropodinae

Hydropsychiidae Ceratopsyche morosa

Cheumatopsyche sp. Hydropsyche scalaris Undetermined Hydropsychidae

Hydroptilidae Hydroptila sp.

Orthotrichia sp. Leptoceridae

Oecetis sp. Diptera

60

Ceratopoginidae Atrichopogon sp. Undetermined Ceratopogonidae

Chironomidae Tanypodinae

Ablabesmyia mallochi Ablabesmyia Larsia Natarsia Pentaneura Procladius Telopelopia Thienemannimyia grp. Undetermined Tanypodinae

Orthocladiinae Brillia sp. Corynoneura sp. Cricotopus bicinctus Cricotopus/Orthocladius complex Cricotopus sp. Nanocladius sp. Orthocladius sp. Parakiefferiella sp. Parametriocnemus sp. Psectrocladius sp. Synorthocladius sp. Thienemanniella sp. Tvetenia bavarica grp. Undetermined Orthocladiinae

Chironominae Chironomus sp. Cryptochironomus sp. Demicryptochironomus sp. Dicrotendipes neomodestus Dicrotendipes nervosus Type 1 Dicrotendipes Undet. Endochironomus nigricans Endochironomus subtendens Endochironomus sp. Einfeldia sp. Glyptotendipes sp. Glyptotendipes sp. 2 Chironomini Harishia complex Microtendipes pedellus grp.

61

Microtendipes sp. Nilothauma sp. Parachironomus sp. Phaenospectra Polypedilum aviceps Polypedilum braseniae Polypedilum flavum Polypedilum halterale grp. Polypedilum illinoense Polypedilum scalaenum Polypedilum tritum Polypedilum sp. Pseudochironomus sp. Tribelos sp. Tribelos/Endochironomus/Phaenopsectra Co Chironomini Undet. Cladotanytarsus sp. Micropsectra/Tanytarsus Complex Micropsectra sp. Paratanytarsus sp. Rheotanytarsus sp. Stempellinella sp. Tanytarsus sp. Tanytarsini Undet. Undetermined Chironominae Undetermined Chironomidae

Diptera Undetermined Pupae