Pulse Events and Arid Ecosystems


, Volume 141, Issue 2, pp 236-253

First online:

Resource pulses, species interactions, and diversity maintenance in arid and semi-arid environments

  • Peter ChessonAffiliated withSection of Evolution and Ecology, University of California Email author 
  • , Renate L. E. GebauerAffiliated withDepartment of Biology, Keene State College
  • , Susan SchwinningAffiliated withSchool of Natural Resources, University of Arizona
  • , Nancy HuntlyAffiliated withDepartment of Biological Sciences, Idaho State University
  • , Kerstin WiegandAffiliated withInstitute of Ecology, University of Jena
  • , Morgan S. K. ErnestAffiliated withDepartment of Biology, University of New Mexico
  • , Anna SherAffiliated withDepartment of Biological Sciences, University of Denver
  • , Ariel NovoplanskyAffiliated withMitrani Department of Desert Ecology, Blaustein Institute for Desert Research, Ben-Gurion University of the Negev
  • , Jake F. WeltzinAffiliated withDepartment of Ecology and Evolutionary Biology, University of Tennesee

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Arid environments are characterized by limited and variable rainfall that supplies resources in pulses. Resource pulsing is a special form of environmental variation, and the general theory of coexistence in variable environments suggests specific mechanisms by which rainfall variability might contribute to the maintenance of high species diversity in arid ecosystems. In this review, we discuss physiological, morphological, and life-history traits that facilitate plant survival and growth in strongly water-limited variable environments, outlining how species differences in these traits may promote diversity. Our analysis emphasizes that the variability of pulsed environments does not reduce the importance of species interactions in structuring communities, but instead provides axes of ecological differentiation between species that facilitate their coexistence. Pulses of rainfall also influence higher trophic levels and entire food webs. Better understanding of how rainfall affects the diversity, species composition, and dynamics of arid environments can contribute to solving environmental problems stemming from land use and global climate change.


Coexistence Precipitation Environmental variability Storage effect Relative nonlinearity