, Volume 55, Issue 3, pp 231–249

Microdistribution of benthic invertebrates in a rocky mountain (U.S.A.) stream

  • G. Wayne Minshall
  • Judy N. Minshall


A study of the benthic invertebrate community inhabiting a small, foothill trout stream in the Rocky Mountains of Idaho was conducted over a two-year period. Monthly Hess samples and short-term experiments using substratum-filled trays were used to describe the spatial dispersion of the benthos and to examine the response of invertebrate populations to substratum and current. A method was devised for measuring available surface area which involved coating individual stones with latex and measuring the area of the ‘print’ resulting from inking the impression left on the latex mold.

The dispersion of all populations was clumped throughout the year. Alteration of the cross-sectional pattern of current velocity and stream bed composition changed the pattern of distribution but not the extent of clumping. Collections made in areas of depositing and eroding substrata revealed a more diverse fauna in the latter. Most groups of organisms found in the riffle were scarcer in the pools or absent from them. The pool fauna contained no important additions over those found in the riffles.

After a year's study of invertebrate populations in an otherwise undisturbed riffle, the substratum was altered and the flow made more uniform; an increase in the abundance of most of the benthic invertebrates followed. No single factor was responsible for the increase, but the change in substratum size and degree of compaction accounted for most of the change. Interpretation of the results was aided by findings from experiments using substratum-filled trays.

Two series of stream experiments using the trays were conducted: one to test the relative importance of current and substratum and the other to test the effect of particle size on the distribution of the benthic fauna. In the first series, placement of trays of stones in a pool resulted in an increase in numbers of some but not all of the invertebrates over numbers usually occurring in the pool. Trays filled with stones and placed in a riffle supported fewer animals than found on the adjacent stream bed but more than in the pool. Variations are attributed to differences in current velocity and amounts of imported organic and inorganic debris. Three different relationships of population numbers to current velocity were found for different members of the community (direct, indirect, and parabolic) over the range of 10 to 60 cm/sec. The second series of experiments consisted of two sets of trays filled with stones of medium or large pebbles, respectively. Nine taxa, as well as all of the combined taxa, showed a preference for trays of small stones over the natural stream bed. A few taxa were noticeably more abundant on the small substratum than on the large but most of the fauna showed only slight increases in numbers or remained constant on the two substrata. Only three taxa showed a direct relation of numbers to total surface area presented by the stones.

Number and kinds of organisms found in trays filled with a uniform size of substratum did not correspond to those taken in Hess samples from the natural stream bed. This has important implications in terms of currently recommended pollution monitoring techniques. However, it is suggested that if the substratum composition of the trays more nearly matched that of the stream, the correspondence would be much better. The results of the present study also throw considerable doubt on the adequacy of generalizations derived from earlier studies of responses to substratum size and suggest several reasons for reevaluating current ideas regarding the influence of substratum on invertebrate distribution.


Streams Benthic invertebrates Microdistribution Substratum Current 


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  1. Allen, K. R. 1959. The distribution of stream bottom faunas. Proc. New Zealand Ecol. Soc. 6: 5–8.Google Scholar
  2. Ambühl, H. 1959. Die Bedeutung der Strömung als ökologischer Faktor. Schweiz. Z. Hydrol. 21: 133–264.Google Scholar
  3. Barber, W. E. & Kevern, N. R. 1973. Ecological factors influencing macroinvertebrate standing crop distribution. Hydrobiologia 43: 53–75.CrossRefGoogle Scholar
  4. Bell, H. L. 1969. Effect of substrate types on aquatic insect distribution. J. Minn. Acad. Sci. 35: 79–81.Google Scholar
  5. Calow, P. 1972. A method for determining the surface areas of stones to enable quantitative density estimates of littoral stone-dwelling organisms to be made. Hydrobiologia 40: 37–50.CrossRefGoogle Scholar
  6. Chutter, F. M. 1969. The distribution of some stream invertebrates in relation to current speed. Int. Revue ges. Hydrobiol. 54: 413–422.CrossRefGoogle Scholar
  7. Chutter, F. M. & Noble, R. G. 1966. The reliability of a method of sampling stream invertebrates. Arch. Hydrobiol. 62: 95–103.Google Scholar
  8. Cianficconi, F. & Riatti, M. 1957. Impiego di pietre artificiali per l'analisi quantitativa delle colonizzazioni faunistiche dei fondi potamici. Boll. Pesca Piscic. Idrobiol. 12: 299–335.Google Scholar
  9. Crossman, J. S. & Cairns, J. Jr. 1974. A comparative study between two different artificial substrate samplers and regular sampling techniques. Hydrobiologia 44: 517–522.CrossRefGoogle Scholar
  10. Cummins, K. W. 1962. An evaluation of some techniques for the collection and analysis of benthic samples with special emphasis on lotic waters. Amer. Midl. Nat. 67: 477–504.CrossRefGoogle Scholar
  11. Cummins, K. W. 1964. Factors limiting the microdistribution of larvae of the caddisflies Pycnopsyche lepida (Hagen) and Pycnopsyche guttifer (Walker) in a Michigan stream. Ecol. Monogr. 34: 271–295.CrossRefGoogle Scholar
  12. Cummins, K. W. & Lauff, G. H. 1969. The influence of substrate particle size on the microdistribution of stream macrobenthos. Hydrobiologia 34: 145–181.CrossRefGoogle Scholar
  13. Edington, J. M. 1968. Habitat preferences in net-spinning caddis larvae with special reference to the influence of water velocity. J. Anim. Ecol. 37: 675–692.CrossRefGoogle Scholar
  14. Egglishaw, H. J. 1964. The distributional relationship between the bottom fauna and plant detritus in streams. J. Anim. Ecol. 33: 463–476.CrossRefGoogle Scholar
  15. Egglishaw, H. J. 1969. The distribution of benthic invertebrates on substrata in fast-flowing streams. J. Anim. Ecol. 38: 19–33.CrossRefGoogle Scholar
  16. Elliott, J. M. 1971. Some methods for the statistical analysis of samples of benthic invertebrates. Freshwat. Biol. Assoc. Sci. Publ. No. 25. 148 p.Google Scholar
  17. Henson, E. B., Jr. 1965. A cage sampler for collecting aquatic fauna. Turtox News 43: 298–299.Google Scholar
  18. Hilsenhoff, W. L. 1969. An artificial substrate device for sampling benthic stream invertebrates. Limnol. Oceanogr. 14: 465–471.CrossRefGoogle Scholar
  19. Hughes, D. A. 1966. Mountain streams of the Barberton area, Eastern Transvaal. Part 2. The effect of vegetational shading and direct illumination on the distribution of stream fauna. Hydrobiologia 27: 439–459.CrossRefGoogle Scholar
  20. Hynes, H. B. N. 1970. The ecology of running waters. Univ. Toronto Press. 555 p.Google Scholar
  21. Jaag, O. & Ambühl, H. 1964. The effect of the current on the composition of biocoenoses in flowing water streams. pp. 31–49 In Int. Conf. Wat. Pollut. Res. Lond. Pergamon Press, Oxford.Google Scholar
  22. Lillehammer, A. 1966. Bottom fauna investigations in a Norwegian river. The influence of ecological factors. Nytt. Mag. Zool. 13: 10–29.Google Scholar
  23. Linduska, J. P. 1942. Bottom type as a factor influencing the local distribution of mayfly nymphs. Can. Ent. 74: 26–30.CrossRefGoogle Scholar
  24. Mason, W. T., Jr., Anderson, J. B. & Morrison, G. E. 1967. Limestone-filled, artificial substrate sampler. Float unit for collecting macro invertebrates in large streams. Progr. Fish Cult. 29: 74.CrossRefGoogle Scholar
  25. Mason, W. T., Jr., Weber, G. I., Lewis, P. A. & Julian, E. C. 1973. Factors affecting the performance of basket and multiplate macro invertebrate samplers. Freshwat. Biol. 3: 409–436.CrossRefGoogle Scholar
  26. Minshall, G. W. & Andrews, D. A. 1973. An ecological investigation of the Portneuf River, Idaho: a semiarid-land stream subjected to pollution. Freshwat. Biol. 3: 1–30.CrossRefGoogle Scholar
  27. Moon, H. P. 1935a. Methods and apparatus suitable for an investigation of the littoral region of oligotrophic lakes. Int. Rev. ges. Hydrobiol. 32: 319–333.Google Scholar
  28. Moon, H. P. 1935b. Flood movements of the littoral fauna of Windermere J. Anim. Ecol. 4: 216–228.CrossRefGoogle Scholar
  29. Moon, H. P. 1939. Aspects of the ecology of aquatic insects. Trans. Soc. Brit. Ent. 6: 39–49.Google Scholar
  30. Moon, H. P. 1940. An investigation of the movements of freshwater faunas. J. Anim. Ecol. 9: 76–83.CrossRefGoogle Scholar
  31. Mottley, C. M., Rayner, H. J. & Rainwater, R. H. 1938. The determination of the food grade of streams. Trans. Amer. Fish. Soc. 68: 336–343.CrossRefGoogle Scholar
  32. Needham, P. R. 1938. Trout streams. Comstock Publ. Co., Inc., Ithaca, N.Y. 233 p.Google Scholar
  33. Needham, P. R. & Usinger, R. L. 1956. Variability in the macrofauna of a single riffle in Prosser Creek, California, as indicated by the Surber sampler. Hilgardia 24: 383–409.CrossRefGoogle Scholar
  34. Paterson, C. G. & Fernando, C. H. 1971. Studies on the spatial heterogeneity of shallow water benthos with particular reference to the Chironomidae. Can. J. Zool. 49: 1013–1019.CrossRefGoogle Scholar
  35. Pennak, R. W. & Van Gerpen, E. D. 1947. Bottom fauna production and physical nature of the substrate in a northern Colorado trout stream. Ecology 28: 42–48.CrossRefGoogle Scholar
  36. Percival, E. & Whitehead, H. 1929. A quantitative study of the fauna of some types of stream-bed. J. Ecol. 17: 282–314.CrossRefGoogle Scholar
  37. Rabeni, C. F. & Minshall, G. W. 1977. Factors affecting the microdistribution of benthic insects. Oikos (in press).Google Scholar
  38. Scott, D. 1958. Ecological studies on the Trichoptera of the River Dean, Cheshire. Arch. Hydrobiol. 54: 340–392.Google Scholar
  39. Scott, D. 1960. Cover on river bottoms. Nature 188: 76–77.CrossRefGoogle Scholar
  40. Scott, D. 1966. The substrate cover-fraction concept in benthic ecology. Pp. 75–78. In K. W. Cummins, C. A. Tryon, and R. T. Hartman (ed.) Organism-substrate relationships in streams. Publ. Pymatuning Lab. Ecol., Univ. Pittsburg. No. 4. 145 P.Google Scholar
  41. Scott, D. & Rushforth, J. M. 1959. Cover on river bottoms. Nature 183: 836–837.CrossRefGoogle Scholar
  42. Slack, K. V., Averett, R. C., Greeson, P. E. & Lipscomb. R. G. 1973. Methods for collection and analysis of aquatic biological and microbiological samples. U.S. Geol. Surv. Tech. Water-Resources Inv. BK 5, Chap. A4 165 p.Google Scholar
  43. Sprules, W. M. 1947. An ecological investigation of stream insects in Algonquin Park, Ontario. Univ. Toronto Stud. Biol. No. 56. Publ. Ont. Fish. Res. Lab. 69: 1–181.Google Scholar
  44. Tarzwell, C. M. 1936. Experimental evidence on the value of trout stream improvement in Michigan. Trans. Amer. Fish. Soc. 66: 177–187.CrossRefGoogle Scholar
  45. Thorup, J. 1966. Substrate type and its value as a basis for the delimitation of bottom fauna communities in running waters. pp. 59–74. In K. W. Cummins, C. A. Tryon, and R. T. Hartman (eds.). Organism-substrate relationships in streams. Publ. Pymatuning Lab. Ecol., Univ. Pittsburg. No. 4. 145 p.Google Scholar
  46. Ulfstrand, S. 1967. Microdistribution of benthic species (Ephemeroptera, Plecoptera, Trichoptera, Diptera: Simuliidae) in Lapland streams. Oikos 18: 293–310.CrossRefGoogle Scholar
  47. Ulfstrand, S. 1968. Benthic animal communities in Lapland streams. A field study with particular reference to Ephemeroptera, Plecoptera, Trichoptera, and Diptera: Simuliidae. Oikos Suppl. 10: 1–120.Google Scholar
  48. Ulfstrand, S., Nilsson, L. M. & Stergar, A. 1974. Composition and diversity of benthic species collectives colonizing implanted substrates in a South Swedish stream. Ent. Scand. 5: 115–122.CrossRefGoogle Scholar
  49. Waters, T. F. & Knapp, R. J. 1961. An improved stream bottom fauna sampler. Trans. Amer. Fish. Soc. 90: 225–226.CrossRefGoogle Scholar
  50. Wene, G. & Wickliff, E. L. 1940. Modification of a stream bottom and its effect on the insect fauna. Can. Ent. 72: 131–135.CrossRefGoogle Scholar
  51. Williams, N. E. & Hynes, H. B. N. 1973. Microdistribution and feeding of the net-spinning caddisflies (Trichoptera) of a Canadian stream. Oikos 24: 73–84.CrossRefGoogle Scholar

Copyright information

© Dr. W. Junk b. v. Publishers 1977

Authors and Affiliations

  • G. Wayne Minshall
    • 1
  • Judy N. Minshall
    • 1
  1. 1.Department of BiologyIdaho State UniversityPocatello

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