Advertisement

Oecologia

, Volume 24, Issue 1, pp 71–81 | Cite as

Differential seed predation on two species of Arctostaphylos (Ericaceae)

  • Jon E. Keeley
  • Robert L. Hays
Article

Summary

The fire-prone California chaparral contains two sympatric species of shrubs: Arctostaphylos glauca and A. glandulosa. A previous study showed that in a stand where both species had similar amounts of coverage, A. glauca had fewer seeds in the soil. We attempt to answer the questions: 1) Could ground-foraging seed predators produce the lower population of A. glauca seeds in the soil? 2) Do predators select fruits randomly with respect to fruit size? 3) Do the fruits of the two species differ in the proportions of fruit components (i.e. seeds, endocarp, mesocarp, and exocarp) in ways that could be important to seed predators? Predation was measured on artificial caches of fruits, for 17 weeks. Selection by predators was examined by comparing weights of fruits recovered from soil samples with newlymatured fruits on the shrubs. Fruits components were characterized by dividing fruits into 3 fractions and weighing. More fruits of A. glauca were removed from the caches. Fruits of both species recovered from the soil were lighter than those on the shrubs. The weights of seeds, stony and fleshy fruit layers were all larger in A. glauca. Within fruits of A. glandulosa, the weights of the three components, various combinations, and ratios were all significantly correlated, while in A. glauca no other component, combination of components, or ratio examined was significantly correlated with the weights of the seeds.

Keywords

Soil Sample Similar Amount Lower Population Seed Predator Fruit Size 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Axelrod, D.I.: History of the mediterranean ecosystem in California, pp. 225–277. In: Mediterranean type ecosystems: Origin and structure. Ecological studies (F. diCastri, H.A. Mooney, eds.), Vol. 7. Berlin-Heidelberg-New York: Springer 1973Google Scholar
  2. Baker, H.C.: Seed weight in relation to environmental conditions in California. Ecology 53, 997–1010 (1972)Google Scholar
  3. Brown, J.H., Lieberman, G.A.: Resource utilization and coexistence of seed-eating desert rodents in sand-dune habitats. Ecology 54, 788–797 (1973)Google Scholar
  4. Dixon, W.G., Massey, F.J., Jr.: Introduction to statistical analysis, 3rd ed., 638 pp. New York: McGraw-Hill 1969Google Scholar
  5. Hanes, T.L.: Succession after fire in the chaparral of Southern California. Ecol. Monogr. 41, 27–52 (1971)Google Scholar
  6. Harper, J.L., Williams, J.T., Sagar, G.R.: The behavior of seeds in soil. I. The heterogenity of soil surfaces and its role in determining the establishment of plants from seed. J. Ecol. 53, 273–286 (1965)Google Scholar
  7. Horton, J., Kraebel, C.: Development of vegetation after fire in the chamise chaparral of Southern California. Ecology 36, 244–262 (1955)Google Scholar
  8. Horton, J.S., Wright, J.T.: The wood rat as an ecological factor in Southern California watersheds. Ecology 25, 341–351 (1945)Google Scholar
  9. Jameson, E.W.: Food of deer mice, Peromyscus maniculatus and P. boylei, in the Northern Sierra Nevada, California. J. Mammal. 33, 50–60 (1952)Google Scholar
  10. Janzen, D.H.: Seed-eaters versus seed size, number, toxicity and dispersal. Evolution 23, 1–27 (1969)Google Scholar
  11. Janzen, D.H.: Seed predation by animals. Annu. Rev. Ecol. Sys. 2, 465–492 (1971)Google Scholar
  12. Jepson, W.L.: Regeneration in manzanita. Madroño 1, 3–11 (1916)Google Scholar
  13. Jepson, W.L.: A Flora of California, Vol. 3, pp. 21–51. Associated Students Store, University of California (1939)Google Scholar
  14. Keeley, J.E.: The adaptive significance of obligate-seeding shrubs in the chaparral. M.S. Thesis, California State University, San Diego, California, 82 pp. (1973)Google Scholar
  15. Plumb, T.R.: Sprouting, of chaparral by December after a wild-fire in July. U.S. Forest Serv., Pacific Southwest Forest and Range Exp. Sta. Tech. Paper 57, 12 pp. (1961)Google Scholar
  16. Rosenzweig, M.L., Sterner, P.W.: Population ecology of desert rodent communities: body size and seed-husking as bases for heteromyid coexistence. Ecology 51, 217–224 (1970)Google Scholar
  17. Salisbury, E.J.: The reproductive capacity of plants, 244 pp. London: Bell 1942Google Scholar
  18. Smigel, B.W., Rosenzweig, M.L.: Seed selection in Dipodomys merriami and Perognathus penicillatus. Ecology 55, 329–339 (1974)Google Scholar
  19. Smith, C.C.: The coevolution of pine squirrels (Tamiasciurus) and conifers. Ecol. Monogr. 40, 349–371 (1970)Google Scholar
  20. Smith, C.F.: The fall food of brushfield pocket mice. J. Mammal. 23, 337–339 (1942)Google Scholar
  21. Wells, P.V.: Vegetation in relation to geological substratum and fire in the San Luis Obispo quadrangle, California. Ecol. Monogr. 32, 89–103 (1962)Google Scholar
  22. Wells, P.V.: The relation between mode of reproduction and extent of speciation in woody genera of the California chaparral. Evolution 23, 264–267 (1969)Google Scholar
  23. Wells, P.V.: The manzanitas of Baja California, including a new species of Arctostaphylos. Madroño 21, 268–273 (1972)Google Scholar

Copyright information

© Springer-Verlag 1976

Authors and Affiliations

  • Jon E. Keeley
    • 1
  • Robert L. Hays
    • 1
  1. 1.Department of BiologySan Diego State UniversitySan DiegoUSA

Personalised recommendations