Abstract
The food resource use of a stream in NW Spain by fish (Salmo trutta L. and Anguilla anguilla L.), birds (Cinclus cinclus L. and Motacilla cinerea L.) and mammals (Galemys pyrenaicus G. and Neomys anomalus C.) was studied. Data on seasonal diets and stream benthos prey were used to determine prey selection patterns.
Caddisfly larvae are the main resource for Cinclus and Galemys, but these predators also consumed other benthic prey. Salmo fed on a wide range of benthic invertebrates, emergent pupae and terrestrial prey, whereas Anguilla consumed primarily benthic invertebrates, especially Lumbricids. Neomys fed mainly on terrestrial prey (Gasteropods and Lumbricids), but also consumed aquatic prey. Motacilla captured aquatic insects both in larval and aerial stages, as well as terrestrial prey.
Both prey availability and selection led to seasonal differences in the use of food resources. All species showed a marked prey selection of aquatic taxa. Prey size plays an important role in this selection, most species consuming the largest of available prey sizes. In spite of the fact that all species feed upon freshwater invertebrates, substantial resource partitioning was observed in all seasons. This partitioning may be attributable to morpholological and physiological differences. Nevertheless, Anguilla and Galemys, two quite different animals, did feed on the same prey much of the time.
Similar content being viewed by others
References
Brown, J. H. & D. W. Davidson, 1977. Competition between seed-eating rodents and ants in desert ecosystems. Science 196: 880–882.
Brown, J. H., D. W. Davidson & O. J. Reichman, 1979. An experimental study of competition between seed-eating desert rodents and ants. Am. Zool. 19: 1129–1143.
Gatz, A. J., 1981. Morphologically inferred niche differentiation in stream fishes. Am. Midl. Nat; 106: 10–21.
Goodge, W. R., 1960. Locomotion and other behavior of the Dipper. Condor 61: 4–17.
Grossman, G. D. & M. C. Freeman, 1987. Microhabitat use in a stream fish assemblage. J. Zool., Lond. 212: 151–176.
Grossman, G. D., M. C. Freeman, P. B. Moyle & J. O. Withaker, 1985. Stochasticity and assemblage organization in an Indiana stream fish assemblage. Am. Nat. 126: 275–285.
Hara, T. G., 1971. Chemoreception. En Fish Physiology, vol V (Eds W. S. Hoar & D. J. Randall). Academic Press, New York.
Heinrich, G., 1948. Zur okologie der ‘wasser’ Spitzmaus Neomys milleri in den bayerischen Alpen. Zool. Jb., Syst. 77: 279–281.
Jost, O., 1975. Zur okologie der wasseramsel (Cinclus cinclus) mit besonderer berucksictigung ihrer ernahrung. Bornner Zoologische Monogr. 6. Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn.
Lechowicz, M. J., 1982. The sampling characteristics of electivity indices. Oecologia 52: 22–30.
Levins, R., 1968. Evolution in changing environments: some theoretical explorations. Monographs in population biology No 2. Princeton Univ. Press, Princeton.
Murrish, D. E., 1970. Responses to diving in the Dipper (Cinclus mexicanus). Comp. Biochem. Physiol. 34: 853–858.
Ormerod, S. J., 1985. The diets of breeding dippers Cinclus cinclus and their nestlings in the catchment of the River Wye, mid Wales: a preliminary study by faecal analysis. Ibis 127: 316–331.
Ormerod, S. J. & Tyler S. J., 1987. Aspects of the breeding ecology of Welsh Grey Wagtails (Motacilla cinerea) Bird Study 34: 43–51.
Pearre, S. Jr, 1982. Estimating prey preference by predators: uses of various indices and a proposal of another based on X2. Can. J. Fish. aquat. Sci. 39: 914–923.
Richard, P. B., 1981. La détection des objets en milieux aquatique et aérien par le Desman des Pyrénées. Behav. Processes 6: 145–159.
Richard, P. B., 1982. La sensibilité tactile de contact chez le Desman (Galemys pyrenaicus). Biol. Behav. 7: 325–336.
Ross, S. T., 1986. Resource partitioning in fish assemblages: A review of field studies. Copeia 2: 352–388.
Santamarina, J., 1990. La alimentación de la Lavandera Cascadeña (Motacilla cinerea) en la Cuenca del Río Ulla (Galicia, NW España). Ardeola 37: 97–101.
Santamarina, J., 1991. Introducción al estudio de las comunidades de vertebrados de los ríos de Galicia: el ejemplo de la cuenca del Ulla. Phd Thesis. Universidad de Santiago, Spain, 242 pp.
Santamarina, J. & J. Guitían, 1988. Quelques données sur le régime alimentaire du desman (Galemys pyrenaicus) dans le nord-ouest de l'Espagne. Mammalia 52: 301–307.
Schifferli, L., 1972. Futteringsfrequenz am nest der Bergstelze (M. cinerea) in verschieden biotopen and Brutmoraten. Der. Orn. Beob. 69: 257–274.
Schoener, T. W., 1968. Theory of feeding strategies. The anolis lizards of Bimini: resource partitioning in a complex fauna. Ecology 49: 704–726.
Smartt, R. A., 1978. A comparison of ecological and morphological overlap in a Petromyscun community. Ecology 59: 216–220.
Sonin, V. D. & N. F. Anuchina, 1979. Migratsii and i ekologiya ptits Sibiri en Labutin. Y V (ed). Yakutsk.
Spitznagel, A., 1985. Seasonal variation in food supply and food choice of the Dipper (Cinclus c. aquaticus). Okol. Vogel 7: 239–325.
Thornhwaite, C. W., 1933. The climats of the earth. Geogr. Rev. 23: 433–440.
Wright, S. J., 1979. Competition between insectivorous lizards and birds in Central Panama. Am. Zool. 19: 1145–1156.