APPENDIX F

 

AN ASSESSMENT OF THE BIOLOGICAL INTEGRITY

OF THE PRAIRIE DOG TOWN FORK OF THE RED RIVER

and

EASTERN CANADIAN RIVER BASIN

 

November 1998

 

BASIN SUMMARY REPORT

FOR THE

RED RIVER BASIN

September 1999

 

 

1.0    Abstract

 

This paper gives insight into the biological health of streams located in the eastern Canadian River Basin in Texas and the Prairie Dog Town Fork of the Red River.  Little information exists on the biological communities of this geographical region, which hinders long-term comparisons.  Hence, both fish and aquatic macroinvertebrates were collected during the summer of 1998 to enable the calculation of biological indices and provide a biological survey for future reference.  Rapid Bioassessment (RBA) methodologies were used for the quantification of biological integrity at eight monitoring stations in these regions.  Results show that intermediate overall biological health of the selected streams in this region.  In comparison to other regions in the state of Texas, the biological communities are definitely impaired.  This is due to natural physical conditions, such as harsh weather conditions, limited habitat, and elevated total dissolved solids.

 

2.0       Introduction

 

This paper presents the results of a bioassessment study of the eastern Canadian River Basin in Texas and the Upper Prairie Dog Town Fork Red River.  The study was performed under a monitoring plan developed under the Texas Clean Rivers Program (CRP) during July of 1998.  Under this plan, biological monitoring plays a major role in supplementing chemical and physical data to provide a complete assessment of water quality in the Red and Canadian River Basins.

 

Collections of fish (Exhibit A) and aquatic macroinvertebrates (Exhibit B) were collected at eight sampling station, which encompasses the entire Canadian River Basin east of Lake Meredith and two stations along the Prairie Dog Town Fork Red River.  These biological collections were then used to calculate a biological integrity score using RBA Protocols (Plafkin et al., 1989).  By performing habitat assessments at these stations, it is possible to determine biological impairment due to water quality, as opposed to natural habitat characteristics.

 

Table 1 provides a description and Figure 1 shows a map of the stations.  These stations are exposed to several different land uses having the potential to impair water quality.

 

Table 1

Description of Monitoring Stations Sampled for Biological Communities on the

Prairie Dog Town Fork Red River and Eastern Region of Canadian River Basin

 

 

 

These include urban activities, such as wastewater effluent discharges and stormwater runoff carrying excess nutrients and pollutants.  Secondly, these stations (to a varying degree) encounter the potential degradation from farming activities, including sedimentation and excess runoff carrying various pollutants.  Lastly, these stations are exposed to ranching activities, which results in sedimentation, introduction of fecal pathogens, and deterioration of the riparian zone/stream banks.

 

3.0    Methods and Materials

 

3.1Rapid Bioassessment Methodology ) Macroinvertebrates

 

Pollution tolerance values for macroinvertebrates were assigned based on values established by the Texas Natural Resource Conservation Commission (personal communication ) Bill Harrison), the EPA (Plafkin, 1989) or from Lenat, 1993.  Functional feeding groups for macroinvertebrate families were assigned based on classifications obtained from Merritt and Cummins (1996).  Several insect families have been assigned multiple functional feeding group classifications by Merritt and Cummins (1996).  In order to clarify these classifications, organisms were further identified to genus, and when possible, to species (Merritt and Cummins, 1996, Parrish R.K., 1975, and Thorp and Covich, 1991).  The data thus recorded was used to score seven metrics for a slightly modified Rapid Bioassessment Protocol II (RBP II) (Plafkin et al., 1989 and Barbour et al., 1992).

Figure 1  map of the stations

Data Analyses

 

The following metrics were scored in the study:

 

Structure Metrics:

 

1.   Taxa Richness = total number of taxa collected at the site.

 

2.   EPT Index  =  number of genera belonging to the Orders Ephemeroptera, Plecoptera, and Trichoptera which were collected.

 

3.   Community Loss Index = (taxa richness at the reference site ) taxa common to reference and sampling sites)/taxa richness at the sampling site.

 

 

Community Balance Metrics:

 

4.   Family Biotic Index (modified) = E(x_i t_i)/n, where:

 

x_i      =          number of individuals within a genus,

t_i       =          tolerance value for the taxa,

n       =          total number of organisms in the sample.

 

5.   Percent Contribution of Dominant Taxa = percent contribution of the dominant taxa to the total number of organisms collected.

 

 

Functional feeding group metrics:

 

6.   Ratio of Scrapers/Filtering Collectors = number of scrapers/(number of scrapers + number of filtering collectors).

 

7.   Quantitative Similarity Index = (Functional Feeding Groups or FFGs) ) compares two communities in terms of presence or absence of FFGs, also taking relative abundance into account.

 

Each metric value obtained was given a Biological Condition Score of 0, 3, or 6, based on its percent comparison to the metric value obtained from reference station data.  Scoring criteria for the Percent Contribution of Dominant Family was expressed as the actual percent contribution, not percent comparability to the reference station.  The Community Loss Index and Quantitative Similarity Index (FFGs) were not given a percent comparability to the reference station, because a comparison to the reference station is incorporated into these indices.  The metric scores for each sampling site were totaled, and compared to the total metric score for the reference site to obtain the Percent Comparability to Reference Site value.  The reference site in this study was Wolf Creek, due to its superior biological and physical health, as well as minimal environmental disturbances.

 

A habitat assessment matrix was completed for each sampling site using forms taken from Plafkin et al., 1989.  The matrices were evaluated to determine percent comparability of habitat between the sampling sites and the reference site.  The percent comparability was used to judge the potential for each sampling site to support a similar level of biological health compared to its reference site.

 

Sampling Methodology

 

The sampling methodology for this study consisted of using a D-framed kicknet to sweep woody habitat, vegetation, and to perform kick samples within riffles.  Due to inconsistencies in the amounts and types of habitat between the sampling sites, a perfectly consistent sampling method could not be implemented.  Therefore, the sampling method consisted of performing five minute sweeps, partitioning the five minutes between the most suitable macroinvertebrate habitats.  The different habitats are sampled approximately the same percentage as they are present.  For example, if the habitat consisted of approximately 60% bank woody habitat and 40% channel woody habitat, then the bank woody habitat would be sampled for three minutes and the channel woody habitat would be sampled for two minutes.  If less than 100 macroinvertebrates are collected after the five minutes, then another five minutes of sampling was conducted.

 

3.1Rapid Bioassessment Methodology ) Fish

 

Fish species were identified and assigned origin groups, tolerance values, and trophic levels (Plafkin et al, 1989; Hubbs, et al, 1991).  This information was used to score eight RBP V (or IBI) metrics (Plafkin et al, 1989).  RBP V allows for some discretion in selecting individual metrics for analysis.  The metrics used to calculate an IBI score for these stations was a modified version developed for fish in the Western High Plains and Southwestern Tablelands (Ecoregions 25 and 26) (Linam, personal communication).

 

Data Analyses

 

The eight metrics which were evaluated in this study were:

 

1.         Total number of species

2.         Number of Cyprinid Species

3.         Number of Sunfish Species

4.         % Omnivores

5.         % as Invertivores

6.         Number of Individuals

7.         % of Individuals as Non-Native Species

8.         % Diseased/Anomalies

 

All metrics, except "total number of individuals" were scored according to the previously cited references.  The "total number of individuals" metric was changed due to different seine mesh sizes being used in this study as compared to mesh sizes used at stations at which the metric scoring criteria were calculated.  Smaller mesh sizes were used at stations used in calculating the metrics, resulting in a greater number of fish to be collected.  A score of one would have been obtained for this metric at all stations, therefore, an alternate methodology was used.  The total number of individuals from each of the 10 stations were ranked and the value at the 90^th percentile was deduced.  This number was split into thirds, giving the three ranges for the metric scoring.  This is consistent with the methodology used for the calculation of other metrics.

 

The metric scoring consists of each metric receiving a 1, 3, or 5, based on its numeric value.  The eight metric scores for each sampling site were totaled to obtain an Index of Biotic Integrity score.  Each sampling site was classified as being in Limited (<24), Intermediate (24-33), High (34-35), or Exceptional (>36).

 

Sampling Methodology

 

Fish were sampled at each site, using a backpack electro-shocking unit and/or seining techniques.  Due to differing conductivity levels and habitat, a consistent fish sampling methodology could not be implemented.  The normal protocol for fish sampling calls for 15 minutes of seining and seven seine hauls.  However, if electro-shocking could not be conducted, then 10 seine hauls were performed.  Additional seine hauls were performed if a new species was collected in the final seine haul, until a seine haul with no new species occurred.  Sampling gear consisted of a Model 12-B Backpack Electro-fisher, a 10 foot seine with ¼ inch mesh, and a 25 foot bag seine with ¼ inch mesh.

 

All habitats, such as snags, rootwads, riffles, and undercut banks were sampled if present, in order to maximize the capture of different fish species.  A representative of each species was preserved in 10% formalin solution and returned to the lab for identification.  All other fish collected were released, unless identification could not be performed in the field.  All fish were identified to species and the number of each species was recorded.

 

4.0       Results and Discussion

 

The overall biological integrity for this geographical region falls into moderately impaired category.  The results are shown in Table 2.  RBA (invertebrates) scores range from 64.3 to 100, showing moderate to no impairment.  RBA (fish) scores ranged from 20 to 40, with most scores falling in the Intermediate category.  Results for this region indicate that physical factors are the prime causes of biological degradation at these stations.  These physical limitations include inadequate substrates, lack of vegetation, sedimentation, and harsh weather conditions.  Another major factor in limiting biological community health is the presence of elevated levels of total dissolved solids in this region (i.e. main stem of Canadian River and main stem Prairie Dog Town Fork Red River).

 

The station scoring the least for the RBA (fish) scoring was Lower Prairie Dog Town Fork Red River at Highway 207.  This station showed Limited biological integrity for its fish community and no benthics were found at this station.  This station is a very harsh, saline environment that possesses virtually no aquatic habitat for sustaining biological life.  The only organism found at this station was the Red River pupfish (Cyprinidon rubrofluviatilis).  This species of fish is common in the Red River basin, as well as some parts of the Canadian River basin and can tolerate high levels of salinity.

 

The Canadian River main stem below Lake Meredith possesses high biological integrity, which is significantly different from reaches above Lake Meredith.  This difference is due strictly to habitat differences.  The substrate below Lake Meredith is heavy sand, as compared to the red silt above the lake, which causes elevated turbidity levels and sedimentation.  More algal growth in the river below Lake Meredith is due to a more stable substrate and adequate light penetration, as compared to above Lake Meredith.

 

Dixon Creek at FM 280 was an interesting station, because a few weeks before the sampling was performed at this station, there was a major fish kill due to a hydrogen sulfide spill by Phillips Petroleum.  Two minnow species and western mosquitofish were collected at this station.  Investigation of the fish kill showed various species of fish extirpated from the creek, such as largemouth bass.  It is concluded that before the fish kill occurred, Dixon Creek would have shown an Exceptional biological integrity, however, it scored a 32 (Intermediate).  The RBA (Benthics) scored a 78.6 (Non-Impaired), which shows that the hydrogen sulfide spill had little effect on the benthic population.

 

The reference site Wolf Creek at FM 1454 is an isolated station in the Northeast corner of the Texas Panhandle.  The station is minimally influenced by anthropogenic activities, which is evident with the high RBA (benthics) score.  The RBA (fish) score showed Intermediate biological integrity, however, upon conversation with the landowner, it was learned that a beaver dam upstream of the sampling station holds an abundance of fish.

 

Table 2

RBA and Habitat Scores

 

 

BIBLIOGRAPHY

 

 

Barbour, M.T., J.L. Plafkin, B.P. Bradley, C.G. Graves, and R.W. Wisseman.  1992.  Evaluation

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Harrison, Bill.  1997.  Personal communication through handout.  Texas Natural Resource

Conservation Commission.

 

Hubbs, Clark, Robert J. Edwards and Gary P. Garrett.  1991.  An Annotated Checklist of the

Freshwater Fishes of Texas with Keys to Identification of Species.  The Texas Journal of Science.  43(4):  Special Supplement.

 

Lenat, David R.  1993.  A Biotic Index for the Southeastern United States:  Derivation and List

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Linam, Gordon.  1998.  Personal communication.  Texas Parks and Wildlife Department.

 

Merritt, R.W. and K.W. Cummins.  1996.  An Introduction to the Aquatic Insects of North

America.  Second Edition.  Kendall/Hunt Publishing Company.  Dubuque, Iowa.  722 pp.

 

Parrish, Fred K.  1975.  Keys to Water Quality Indicative Organisms of the Southeastern United

States.  United States Environmental Protection Agency.  2^nd Edition.  Cincinnati.

 

Plafkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross and R.M. Hughes.  1989.  Rapid

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Thorp, James H. and Alan P. Covich.  1991.  Ecology and Classification of North American

Freshwater Invertebrates.  Academic Press, Inc.  San Diego.  911 pp.