Oecologia

, Volume 67, Issue 3, pp 342–351 | Cite as

Community and population dynamics of serpentine grassland annuals in relation to gopher disturbance

  • R. J. Hobbs
  • H. A. Mooney
Original Papers

Summary

This study examines the effects of soil disturbance by gophers on patterns of species abundance in an annual grassland community on serpentine soil. We assessed production, dispersal and storage of seed, germination, survivorship and growth of the most abundant species in undisturbed vegetation and on gopher mounds. Fewer seeds of the dominant species were dispersed onto gopher mounds due to the limited movement of seeds from within the closed vegetation. Species with taller flowering stalks were more likely to colonise gopher mounds. The timing of gopher disturbance in relation to the timing of seed fall determined which species could colonise mounds. Lower numbers of seeds falling onto gopher mounds resulted in lower seedling densities of several species compared with undisturbed areas. Survivorship of the commonest species differed between undisturbed areas and gopher mounds formed at different times of year. This resulted in characteristic spectra of species abundance on the different microhabitats, giving rise to distinct spatial patterning in the community. Plants growing on gopher mounds were generally larger and produced more seed than plants in undisturbed vegetation. We suggest that continued gopher disturbance is a factor allowing several species, including perennial grasses, to persist in this community.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Bartolome JW (1979) Germination and seedling establishment in California annual grassland. J Ecol 67:273–281Google Scholar
  2. Bartolome JW (1981) The ecological status of Stipa pulchra (Poaceae) in California. Madroño 28:172–184Google Scholar
  3. Burtt BL (1977) Aspects of diversification in the capitulum. In: Heywood VH, Harborne JB, Turner BL (eds) The biology and chemistry of the Compositae. vol I. Academic Press, London New York, pp 41–59Google Scholar
  4. Dirzo R, Sarukhan J (eds) (1984) Perspectives in plant, population biology. Sinauer Associates. Sunderland MassachusettsGoogle Scholar
  5. Ellison L, Aldous CM (1952) Influence of pocket gophers on vegetation of subalpine grassland in central Utah. Ecology 33:177–186Google Scholar
  6. Fitch HS, Bentley JR (1949) Use of California annual-plant forage by range rodents. Ecology 30:307–321Google Scholar
  7. Foster MA, Stubbendieck J (1980) Effects of plains pocket gopher (Geomys bursarius) on rangeland. J Range Manage 33:74–78Google Scholar
  8. Gettinger RD (1984) Energy and water metabolism of free-ranging pocket gophers Thomomys bottae. Ecology 65:740–757Google Scholar
  9. Grubb PJ (1977) The maintenance of species-richness in plant communities: the importance of the regeneration niche. Biol Rev 52:107–145CrossRefGoogle Scholar
  10. Gulmon SL (1979) Competition and coexistence: three annual grass species. Am Midl Nat 101:403–416Google Scholar
  11. Gulmon SL, Chiariello NR, Mooney HA, Chu CC (1983) Phenology and resource use in three co-occurring grassland annuals. Oecologia (Berlin) 58:33–42Google Scholar
  12. Harper JL (1977) Population biology of plants. Academic Press, London New YorkGoogle Scholar
  13. Hobbs RJ (1985) Harvester ant foraging and plant species distribution in annual grassland. Oecologia (Berlin) (in press)Google Scholar
  14. Howard WE, Childs HE (1959) Ecology of pocket gophers with emphasis on Thomomys bottae Mewa. Hilgardia 29:277–358Google Scholar
  15. Huston M (1979) A general hypothesis of species diversity. Am Nat 113:81–101CrossRefGoogle Scholar
  16. Law R (1981) The dynamics of a colonizing population of Poa annua. Ecology 62:1267–1277Google Scholar
  17. Laycock WA (1958) The initial pattern of revegetation of pocket gopher mounds. Ecology 39:346–351Google Scholar
  18. McEvoy PB (1984) Dormancy and dispersal of dimorphic achenes of tansy ragwort Senecio jacobaea L. (Compositae). Oecologia (Berlin) 61:160–168Google Scholar
  19. McNaughton SJ (1968) Structure and function in California grasslands. Ecology 49:962–972Google Scholar
  20. Maarel E van der (1984) Dynamics of plant populations from a synecological viewpoint. In: Dirzo R, Sarukhan J (eds) Perspectives in plant population ecology. Sinauer Associates. Sunderland Massachusetts, pp 66–82Google Scholar
  21. Mallik AU, Hobbs RJ, Legg CJ (1984) Seed dynamics in Calluna — Arctostaphylos heath in Scotland. J Ecol 72:855–871Google Scholar
  22. Mielke HW (1977) Mound building by pocket gophers (Geomyidae): their impact on soils and vegetation in North America. J Biogeog 4:171–180Google Scholar
  23. Miller MA (1948) Seasonal trends in burrowing of pocket gophers (Thomomys). J Mammal 29:38–44Google Scholar
  24. Platt WJ (1975) The colonisation and formation of equilibrium plant species associations on badger disturbances in a tallgrass prairie. Ecol Monogr 45:285–305Google Scholar
  25. Proctor J, Whitten K (1971) A population of the valley pocket gopher (Thomomys bottae) on a serpentine soil. Am Midl Nat 78:176–179Google Scholar
  26. Rabinowitz D, Rapp JK (1980) Seed rain in a North American tall grass prairie. J Appl Ecol 17:793–802Google Scholar
  27. Schaal BA, Leverich WJ (1982) Survivorship patterns in an annual plant community. Oecologia (Berlin) 54:149–151Google Scholar
  28. Sharitz RR, McCormick JF (1973) Population dynamics of two competing annual plant species. Ecology 54:723–739Google Scholar
  29. Sheldon JC, Burrows FM (1973) The dispersal effectiveness of achene-pappus units of selected Compositae in steady winds with convection. New Phytol 72:665–675Google Scholar
  30. Silvertown JW (1982) Introduction to plant population ecology. Longman, London New YorkGoogle Scholar
  31. Singer MC, Ehrlich PR (1979) Population dynamics of the checkerspot butterfly Euphydryas editha. In: Halbach V, Jacobs J (eds) Population ecology. Fortschr Zool 25:29–52, Fischer, StuttgartGoogle Scholar
  32. Tilman D (1983) Plant succession and gopher disturbance along an experimental gradient. Oecologia (Berlin) 60:285–292Google Scholar
  33. Turitzin SN (1981) Nutrient limitations to plant growth in a California serpentine grassland. Am Midl Nat 107:95–99Google Scholar
  34. Watkinson AR (1978) The demography of a sand dune annual: Vulpia fasciculata III. The dispersal of seeds. J Ecol 66:483–493Google Scholar
  35. Verkaar HJ, Schenkeveld AJ, Klashorst MP van der (1983) The ecology of short-lived forbs in chalk grasslands: dispersal of seeds. New Phytol 95:335–344Google Scholar
  36. Young JA, Evans RA, Raguse CA, Larson JR (1981) Germinable seeds and periodicity of germination in annual grasslands. Hilgardia 49(2):1–37Google Scholar

Copyright information

© Springer-Verlag 1985

Authors and Affiliations

  • R. J. Hobbs
    • 1
  • H. A. Mooney
    • 1
  1. 1.Department of Biological SciencesStanford UniversityStanfordUSA

Personalised recommendations