, Volume 141, Issue 2, pp 211–220 | Cite as

Hierarchy of responses to resource pulses in arid and semi-arid ecosystems

  • Susanne SchwinningEmail author
  • Osvaldo E. Sala
Pulse Events and Arid Ecosystems


In arid/semi-arid ecosystems, biological resources, such as water, soil nutrients, and plant biomass, typically go through periods of high and low abundance. Short periods of high resource abundance are usually triggered by rainfall events, which, despite of the overall scarcity of rain, can saturate the resource demand of some biological processes for a time. This review develops the idea that there exists a hierarchy of soil moisture pulse events with a corresponding hierarchy of ecological responses, such that small pulses only trigger a small number of relatively minor ecological events, and larger pulses trigger a more inclusive set and some larger ecological events. This framework hinges on the observation that many biological state changes, where organisms transition from a state of lower to higher physiological activity, require a minimal triggering event size. Response thresholds are often determined by the ability of organisms to utilize soil moisture pulses of different infiltration depth or duration. For example, brief, shallow pulses can only affect surface dwelling organisms with fast response times and high tolerance for low resource levels, such as some species of the soil micro-fauna and -flora, while it takes more water and deeper infiltration to affect the physiology, growth or reproduction of higher plants. This review first discusses how precipitation, climate and site factors translate into soil moisture pulses of varying magnitude and duration. Next, the idea of the response hierarchy for ecosystem processes is developed, followed by an exploration of the possible evolutionary background for the existence of response thresholds to resource pulses. The review concludes with an outlook on global change: does the hierarchical view of precipitation effects in ecosystems provide new perspectives on the future of arid/semiarid lands?


Climate change Ecosystem structure Precipitation thresholds Precipitation variability Rainfall size 



This research was supported by the US National Science Foundation grant DEB #0222313, the InterAmerican Institute for Global Change Research, the Agencia Nacional de Promoción Científica y Técnica, and the University of Buenos Aires. We thank all the participants of the workshop “Resource pulse utilization in arid and semiarid ecosystems” for stimulating discussion, and especially Jim Ehleringer for his leadership role in developing the idea for this workshop. We also wish to thank Jayne Belnap and two anonymous reviewers for their suggestions on the manuscript.


  1. Austin TA, Yahdjian ML, Stark JM, Belnap J, Porporato A, Burke IC, Choromanska U, Ravetta D, Schaeffer SM (2004) Water pulses and biogeochemical cycles in arid and semiarid ecosystems. Oecologia (in press)Google Scholar
  2. Beatley JC (1974) Phenological events and their environmental triggers in Mojave-desert ecosystems. Ecology 55:856–863Google Scholar
  3. Belnap J, Phillips SL, Miller ME, Flint SD (2004) Response of desert biological soil crusts to alterations in precipitation frequency. Oecologia 10.1007/s00442-003-1438-6Google Scholar
  4. Bertolin G, Rasmussen J (1969) Preliminary report on the study of the precipitation in the Pawnee National Grasslands. In: US International Grassland Biome. Technical Report No 17. Colorado State University, Fort Collins, p 48Google Scholar
  5. Bowers JE (1996) Seedling emergence on Sonoran Desert dunes. J Arid Environ 33:63−72CrossRefGoogle Scholar
  6. Brown JH, Valone TJ, Curtin CG (1997) Reorganization of an arid ecosystem in response to recent climate change. Proc Natl Acad Sci USA 94:9729–9733CrossRefPubMedGoogle Scholar
  7. Bull JJ, Shine R (1977) Iteroparous animals that skip opportunities for reproduction. Am Nat 114:298–303Google Scholar
  8. Chapin FSI, Sala OE, Burke IC, Grime JP, Hooper DU, Lauenroth WK, Lombard A, Mooney HA, Mosier AR, Naeem S, Pacala SW, Roy J, Steffen WL, Tilman D (1998) Ecosystem consequences of changing biodiversity. Bioscience 48:45–52Google Scholar
  9. Comstock JP, Ehleringer JR (1992) Plant adaptations in the Great Basin and Colorado Plateau. Great Basin Nat 52:195–215Google Scholar
  10. Cui M, Caldwell MM (1997) A large ephemeral release of nitrogen upon wetting of dry soil and corresponding root responses in the field. Plant Soil 191:291–299CrossRefGoogle Scholar
  11. Daly C, Bachelet D, Lenihan JM, Parton W, Neilson RP, Ojima D (2000) Dynamic simulation of tree-grass interactions for global change studies. Ecol Appl 10:449–469Google Scholar
  12. Fravolini A, Hultine KA, Koepke DF, Williams DG (2003) The role of soil texture on mesquite water relations and response to summer precipitation. In: Santa Rita experimental range: one hundred years (1903 to 2003) of accomplishments and contributions; conference proceedings; 30 October to 1 November 2003, Tucson, Ariz. Proc. RMRS-P-00. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Ogden, UtahGoogle Scholar
  13. Freckman DW (1986) The ecology of dehydration in soil organisms. In: Leopold AC (ed) Membranes, metabolism and dry organisms. Cornell University Press, Ithaca, pp 16, 157–168Google Scholar
  14. Golluscio RA, Sala OE, Lauenroth WK (1998) Differential use of large summer rainfall events by shrubs and grasses: a manipulative experiment in the Patagonian steppe. Oecologia 115:17–25CrossRefGoogle Scholar
  15. Gregory JM, Mitchell JFB, Brady AJ (1997) Summer drought in northern mid-latitudes in a time-dependent CO2 climate experiment. J Climatol 10:662–686CrossRefGoogle Scholar
  16. Jackson RB, Canadell J, Ehleringer JR, Mooney HA, Sala OE, Schulze ED (1996) A global analysis of root distributions for terrestrial biomes. Oecologia 108:389–411Google Scholar
  17. Jaksic FM, Lima M (2003) Myths and facts on ratadas: bamboo blooms, rainfall peaks and rodent outbreaks in South America. Aust Ecol 28:237–251CrossRefGoogle Scholar
  18. Krebs JR, Davies NB (1993) An introduction to behavioural ecology. Blackwell Scientific, Oxford, UKGoogle Scholar
  19. Lauenroth WK, Sala OE, Milchunas DG, Lathrop RW (1987) Root dynamics of Bouteloua gracilis during short-term recovery from drought. Funct Ecol 1:117–124Google Scholar
  20. Loik ME, Breshears DD, Lauenroth WK, Belnap J (2004) Climatology and ecohydrology of precipitation pulses in arid and semiarid ecosystems of the western USA. Oecologia (in press)Google Scholar
  21. Madsen T, Shine R (1999) Rainfall and rats: climatically driven dynamics of a tropical rodent population. Aust J Ecol 24: 80–89CrossRefGoogle Scholar
  22. Nicholls N, Gruza G, Jouzel J, Karl T, Ogallo L, Parker DE (1996) Observed climate variability and change. In: Houghton JT, Meira Filho LG, Callander BA, Harris N, Kattenberg A, Maskell K (eds) Climate change 1995. Cambridge University Press, Cambridge, pp 132–192Google Scholar
  23. Noy-Meir I (1973) Desert ecosystems: environment and producers. Annu Rev Ecol Syst 4:25–51CrossRefGoogle Scholar
  24. Ogle K, Reynolds JF (2004) Historical, revised and new paradigms on the role of precipitation pulses in structuring desert plant community composition and productivity. Oecologia 10.1007/s00442-004-1507-5Google Scholar
  25. Ostfeld RS, Keesing F (2000) Pulsed resources and community dynamics of consumers in terrestrial ecosystems. Trends Ecol Evol 15:232–237PubMedGoogle Scholar
  26. Reynolds JF, Virginia RA, Kemp PR, de Soyza AG, Tremmel DC (1999) Impact of drought on desert shrubs: effects of seasonality and degree of resource island development. Ecol Monogr 69:69–106Google Scholar
  27. Reynolds, JF, Kemp PR, Fernández RJ, Ogle K (2004) Plant functional-type responses in the warm deserts of North America: “drinking from the same cup” in pulsed environments. Oecologia 10.1007/s00442-004-1524-4Google Scholar
  28. Ryel RJ, Leffler AJ, Peek MS, Ivans CY, Caldwell MM (2004) Water conservation in Artemisia tridentata through redistribution of precipitation. Oecologia 10.1007/s00442-003-1421-2Google Scholar
  29. Sala OE, Lauenroth WK (1982) Small rainfall events: an ecological role in semiarid regions. Oecologia 53:301–304Google Scholar
  30. Sala OE, Lauenroth WK, Parton WJ, Trlica MJ (1981) Water status of soil and vegetation in a shortgrass steppe. Oecologia 48:327–331Google Scholar
  31. Sala OE, Lauenroth WK, Parton WJ (1982) Plant recovery following prolonged drought in a shortgrass steppe. Agric Meteorol 27:49–58CrossRefGoogle Scholar
  32. Sala OE, et al (2000) Global biodiversity scenarios for the year 2100. Science 287:1770−1774CrossRefPubMedGoogle Scholar
  33. Schenk HJ, Jackson RB (2002) Rooting depths, lateral root spreads and below-ground above ground allometries of plant in water limited ecosystems. J Ecol 90:480–494CrossRefGoogle Scholar
  34. Schlesinger WH, Pilmanis AM (1998) Plant-soil interactions in deserts. Biogeochemistry 42:169–187Google Scholar
  35. Schwinning S, Ehleringer JR (2001) Water use trade-offs and optimal adaptations to pulse-driven arid ecosystems. J Ecol 89:464–480CrossRefGoogle Scholar
  36. Schwinning S, Davis K, Richardson L, Ehleringer JR (2002) Deuterium enriched irrigation indicates different forms of rain use in shrub/grass species of the Colorado Plateau. Oecologia 130:345–355CrossRefGoogle Scholar
  37. Schwinning S, Starr BI, Ehleringer JR (2003) Dominant cold desert plants do not partition warm season precipitation by event size. Oecologia 136:252–260CrossRefPubMedGoogle Scholar
  38. Silvertown J (1991) Modularity, reproductive thresholds and plant population dynamics. Funct Ecol 5:577–582Google Scholar
  39. Smith RE, Schreiber HA (1974) Point processes of seasonal thunderstorm rainfall. 2. Rainfall depth probabilities. Water Resour Res 10:418–423Google Scholar
  40. Smith SD, Monson RK, Anderson JE (1997) Physiological ecology of North American desert plants. Springer, Berlin Heidelberg New YorkGoogle Scholar
  41. Tudhope A, et al (2001) Variability in the El Niño-southern oscillation through a glacial-interglacial cycle. Science 291:1511–1517CrossRefPubMedGoogle Scholar
  42. Vandermeer J, Yodzis P (1999) Basin boundary collision as a model of discontinuous change in ecosystems. Ecology 80:1817–1827Google Scholar
  43. Westoby M (1972) Problem-oriented modelling: a conceptual framework. In: IBP/Desert Biome, Information Meeting, Tempe, Ariz.Google Scholar
  44. Williams DG, Ehleringer JR (2000) Intra- and interspecific variation for summer precipitation use in pinyon juniper woodlands. Ecol Monogr 70:517–537Google Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.School of Natural ResourcesUniversity of ArizonaTucsonUSA
  2. 2.Department of Ecology and IFEVA, Faculty of AgronomyUniversity of Buenos Aires and CONICETBuenos AiresArgentina

Personalised recommendations