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A Total Forest Management Plan
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Information on Warm Water Streams is available.
See Silver Waters
Many forest streams provide esthetic benefits and increase land value. They can be fishing streams and thus of interest to some 27 percent of the U.S. population that goes fishing. How forests are managed can influence forest streams and, in addition to fishing quality, influence:
Forests contribute to the organic matter in streams, thus to the food of insects, crayfish, and other creatures as well as to the fish that feed on them. The leaves, bark, twigs, etc. that fall into streams contribute 70-80% of the food energy of these creatures within the water. The insects falling into the water from overhead vegetation is even more important to the fish than he insects within the water.
Vegetation over streams, often called that in the riparian volume, particularly that providing shade between 10 AM and 2 PM, is critical in regulating stream temperature. Trout require cool temperatures; other species require warm water.
Forests, when well managed, can reduce sediment in streams. Particularly hard on some organisms, sediment fills in pools (critical habitat for large fish) and buries spawning and feeding surfaces. When sediment loads in streams increase, streams become wider, have less shade, and water temperature increases. In the stream, as elsewhere in the forest ecosystem, one change usually produces several other changes. Stream sediment (sand and silt), as little as 17 parts per million, can have harmful effects on fish in streams. Any improvement in reducing stream sediment will probably increase the life in the stream. Bridges, crossings, culverts, and interior road ditches can be very harmful in producing silt.
Streams need to be "stair-stepped" with rocks and old large logs and large tree limbs to reduce water velocities, reduce scouring, and to form pools.
Landowners who preserve forests are fish habitat managers. They need to know it and be proud. They are also potential groundwater managers. By making small streams stair-stepped, forest owners increase groundwater recharge and (most importantly) reduce channel cutting or the depth of small valleys. The lower the stream, the lower the groundwater. The lower the groundwater, the lower the site index, a measure of how productive a site is for tree growth.
Streams are innately valuable resources and they contain valuable resources. This section concentrates on the stream itself but fish and other organisms must also be addressed. Be sure to study stream related components of The Fishery.
It may be interesting to locate a stream or watershed of interest and to consider it as you read and study this unit.
Platts(1976) argued for an interdisciplinary approach to the streamflow problem. The approach, in my judgement, is identical to that of a systems approach advocated earlier. Platts believed stream problems exceeded the capabilities of any person in a discipline. He listed in sequence "identifying the problem"which the systems oriented person usually believes to follow the "clarify the objectives." The difference is that the problem is found in the gap between the present state and the desired state, namely when the objectives are achieved. Objectives first! Platts than stresses designing the problem boundaries (stating the context), identifying data needs (inputs), determining the critical path of accomplishment (optimization processes), coordination and analyses (other types of processes), reports (outputs), decision making, and evaluation (feedback). Platts' concerns grew from awareness of the complexities of the stream and streamflow management.
He said that the stream management difficulties were due to:
He seemed to long for a model, a comprehensive system, that would document, describe, evaluate, and fulfil human needs and yet protect or enhance the physical and biological resources of the stream over time. He saw the problems of the stream as being beyond comprehension (requiring talents of engineers, hydrologists, aquatic ecologists, fishery biologists, soil scientists, landscape architects, wildlife biologists, and range scientists ...all working with administrators, land managers, politicians, lawyers, economists, and sociologists). The Trevey attempts to be even more comprehensive. The task is daunting and understanding of the limitation of any resource-related system is sought (as well as assistance in overcoming the limitations.) Work is underway.
Streams are not streams but baseflow (autumn) streams, modal streams, and peak (bankfull) streams. In baseflow streams, the total pool surface area is large, there are more pools, and they are small. Total area of riffles is decreased (that's what's left of interest after the pools are subtracted in an analysis). The wetted surface area decreases. These observations reguire that any biological or chemical samples from streams be compared from streams with similar discharges. A good sample from one stream channel at any discharge level is difficult and costly to get and analyze. Getting comparable samples from even two streams is almost impossible. A rationally robust approach to stream analysis seems imperative.
Streams are complex and diverse. Streams in the mountains are strongly influenced by large wood that is within them or at the edges. Large wood created pools, stores inorganic sediments and organin matter, and creates a stepped channel profile. Wood cuases abrupt and persistent changes in channel patterns and positions and it is the major structural element responsible for backwater and side-channel formation.
Large wood maintains spaces for fish by altering the stream velocity, providing volumes where fish may feed and trapping biological matter, giving many organisms an opportunity to feed on or otherwise process it. Wood also provides protection to some forms from predators, shelter during high wiwnter and spring flows, and an important attachment and feeding surface for invertebrate animals. One study in the Arkansas Ouachita Mountains found that "fill" exceded scour by two or more times in step-pool reaches.
We have adopted a meaning of "large wood" in streams as any piece of natural wood that is more than 8 feet long (2.5 m) or more than 10 inches in diameter (25 cm). (This is half the piece-dimensions used in the West (Oregon).
By placing large wood and boulders in streams, channels can begin recovery and fish populations along with them.
We might count the large pieces along a 1000 m stream reach (or reaches) e.g., 210 pieces. After 10 years and stream restoration, the count along the same stretch might be 2200. Comparisons of fish numbers in the same stretch might show increasdes over the baseline condition.
Stream Structure
Swanson and others (1988) and Gregory (1988) have laid out a hierarchical spatial scale for streams and riparian volumes.
Length of stream that is in pools can be compared and changes can be noted in percentage of the stream length that is in pools, also that in side channel habitats (e.g., 10% changing to 16 percent).
The progress anticipated and sought by management is in:
These should correlate well with fish populations as well as stream invertebrates as sampled by many techniques. The persistent increases and the extreme variability (by stream, month, and year) suggest that sampling be restricted to gross measures of zoo-mass. Weller and others (1988) found that 95% of the variability in water discharge and 80-90% of the variability in N and P discharges of streams was associated with one of the spatial or temporal scales considered. Some 5 to 20% was related to measurement error or unique events. Difference among years was most important, then seasonality, then differences among watersheds. For P, seasonality and year-to-year variability most influenced variations. No lengthy identification of aquatic species is justified because of high costs, long delays, and the logarithmic relationship of the total with the most abundant 3 to 5 major taxa (easily separated).
Warmwater Streams
Warmwater streams represent an extremely important recreational asset in the south, providing hundreds of thousands of acres of potentially good fishing water. Streams ranging from less than 7 feet in average width to those in excess of 300 feet can provide excellent fishing, if certain basic considerations are met.
Four major factors influence the quality of the fishing in any warmwater stream. Water quality, food supplies, cover, and water temperatures must all be favorable to produce good fishing, while the best fishing is brought about by an optimum mix of the four.
Water Quality
Survival and growth of warmwater fishes is highly dependent on water quality which, in turn, is strongly influenced by land uses in the surrounding area, particularly by the dumping of municipal and/or chemical wastes into the watershed. State biologists are usually available to test streams for water quality, to determine sources of pollution and to make recommendations for correction.
Food
Aquatic insects such as mayflies, stoneflies, and caddis flies make up the bulk of the diet of small fish that inhabit warmwater streams. These small fish, in turn, comprise the basic diet of larger fish and on up the line. Therefore, a large food base of aquatic insects is important to support the range of fish species and sizes usually found in a quality fishing stream. The abundance of aquatic insects in an on the stream bottom largely determines the number of fish a stream can support. Both the abundance and diversity of these insects is, in turn, governed by the quality of the water.
Cover
Instream cover in the form of logjams, rootwads, fallen trees, rock ledges, aquatic vegetation, and deep holes are necessary to provide the habitat needed to support large fish populations. Cover is needed from the banks. In streams where all cover has been removed by channelization, the fish population has been reduced by as much as 87%. This in itself shows the important role instream cover plays in influencing the fish population in warmwater streams. These structures also provide shade, helping to reduce daily water temperature fluctuations. Streams deficient in this habitat element can be improved by adding structures such as brush piles, large rocks, etc. Care must be taken, however, to ensure that the flow of water is not impeded or flooding may occur during periods of heavy rainfall.
Water Temperature
Fluctuations in water temperature are usually more several in warmwater streams than in cold water or trout streams. Optimum temperature for survival and growth of most warmwater fish species is between 70 and 85 degrees. To provide acceptable fishing, water temperatures should never exceed 90 degrees or fall to near freezing.
Warmwater Fish Species
Common sport fish inhabiting streams include smallmouth and largemouth basses, white and black crappies, bluegill, rock bass (goggle eye), green sunfish, and longear sunfish. Flathead, blue and channel catfish can also be present in large numbers, depending upon stream conditions.
There are also a few seasonal inhabitants such as walleye, sauger, and white bass, all of which migrate up large streams in the early spring months to spawn. This wide variety of sport fish commonly found in warmwater streams can provide excellent fishing opportunities. However, these streams are overlooked by a large majority of fishermen.
Stocking
Stocking fish in warmwater streams is not recommended since most streams, under normal circumstances, will be supporting the population it is capable of maintaining unless conditions in the steam have been altered recently. If the stream is near its carrying capacity, the newly stocked fish could upset the delicate natural "balance" between predator and prey species. This could cause a reduction in prey species which, in turn, would result in the reduction of predator species to a level below that which existed prior to stocking. Stream fish also tend to move within a stream. A fish released at one point might not set up housekeeping until it has moved several miles, upstream or downstream, from the point of stocking.
Stream Monitoring
Rural System work on stream monitoring starts with the question of "why"? for that answer requires objectives. What will be done with the results if they can be imagined already in hand. If nothing can be readily stated, it is best to delay action called monitoring. The appropriate answers, differing for each stream situation, and each given different importance and substitution for the time available:
We need moderately precise data, trading off between gross subjective estimates and observations with little quantification (fast and low cost but with little potential for analyses) against detailed very precise measures (that take much time and expertise, are costly, but allow quantitative analyses). There is no monitoring procedure or protocol that is easy to apply, quantitatively adequate, and inexpensive.
Comparing streams as the basis for detecting change in one stream is impossible for each stream is unique. Before-and-after studies are needed.
Stream systems, all parts of them, are highly variable and factors affect each other and thus time-line studies, 30 years minimum, and expensive to get and keep, are unlikely to yield solid conclusions. Some factors are fairly constant and unaffected by land use changes (e.g., stream gradient). Others are profound, of very short duration, and easily missed in sampling.
Stream measures that have low observer variability need to be selected (e.g., width and depth (for that ratio), stream reaches (mapped length and location) with structures, streambank conditions, and cross-section area and shape).
Literature and References
Gregory, S. and R. Wildman. 1998. Aquatic ecosystem restoration project: Quartz Creek post-flood progress report, Willamette Natl. For., Eugene, OR 75pp.
Gregory, S.V. 1988. Influence of valley floor landform on stream ecosystems (abstract) 3rd Ann. Landscape Ecol Symposium, Observations across scales, Univ New Mexico, Albuquerque, NM.
Hickman, 1975. Value of instream cover to the fish populations of the Middle Fabius River, Missouri. Missouri Department of Conservation, Aquatic Series No. 14.
Schneberger and Funk, 1971. Stream Channelization, A Symposium. N.C. Division of Amer. Fish. Soc., Spec. Publ. No. 2.
Lagler, 1956. Freshwater Fishing Biology
Swanson, F.J., G.E. Grant, and A McKee. 1988 . Geomorphic basis for analysis of terrestrial-aquatic interactions.(Abstract) 3rd Ann. Landscape Ecol Symposium, Observations across scales, Univ New Mexico, Albuquerque, NM.
Weller, D.E., D.L. Correll and T.E. Jordan 1988. Identifying temporal and spatial scales of variability in watershed discharges.(Abstract) 3rd Ann. Landscape Ecol Symposium, Observations across scales, Univ New Mexico, Albuquerque, NM.
See The Warmwater Streams Committee (AFS)was established in 1976 as a technical committee within the Southern Division of the American Fisheries Society in order to address issues related to warmwater streams. The Committee promotes the conservation and management of warmwater streams by providing a forum for the exchange of ideas, information, and concerns.
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Last revision July 13, 2001.