Differential response of two kangaroo rats (Dipodomys) to the 1997-1998 El Niño Southern Oscillation event

D. A. Kelt, J. A. Wilson, Eddy S. Konno

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

In southern California the Dulzura kangaroo rat (Dipodomys simulans) occurs in shrub-dominated habitats adjacent to forb- or grass-dominated habitats, which support the endangered Stephens's kangaroo rat (D. stephensi). We monitored a number of populations of both species from 1996 through 2000, spanning the 1997-1998 El Niño Southern Oscillation (ENSO) event. Although populations of D. stephensi were not significantly impacted by this climatic event, D. simulans declined from 10-24 individuals/ha to about 7-12 individuals/ha over a 6- to 8-month period; numbers subsequently continued to decline to 1-2 individuals/ha and failed to recover in the approximately 2.5 years of post-ENSO monitoring. We noticed no signs of sickness or illness among these animals, although adult body masses of D. simulans (but not D. stephensi) declined through the ENSO event, suggesting that food resources for the former species may have been compromised. Alternatively, populations of D. simulans may have been unusually high before the ENSO event, such that the onset of rains merely hastened a predictable winter die-off. Finally, other rodents could have robbed seeds from the food caches of Dulzura kangaroo rats, influencing the ability of the latter to survive the ENSO event. Although this explanation remains speculative, cache pilferage has been demonstrated among other heteromyids, and a recent theoretical study suggests this may be an important mechanism of species coexistence. Further investigations of cache pilferage could enhance our understanding of the ecology and evolution of these diverse small mammal assemblages.

Original languageEnglish (US)
Pages (from-to)265-274
Number of pages10
JournalJournal of Mammalogy
Volume86
Issue number2
DOIs
StatePublished - Apr 1 2005

Fingerprint

Dipodomys
Southern Oscillation
oscillation
Ecosystem
Population
Food
Rain
die-off
Poaceae
Ecology
food
Mammals
habitat
Rodentia
Seeds
small mammal
habitats
theoretical study
small mammals
Theoretical Models

Keywords

  • Cache pilferage
  • Dipodomys simulans
  • Dipodomys stephensi
  • ENSO
  • El Niño Southern Oscillation
  • Endangered species

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Animal Science and Zoology
  • Genetics
  • Nature and Landscape Conservation

Cite this

Differential response of two kangaroo rats (Dipodomys) to the 1997-1998 El Niño Southern Oscillation event. / Kelt, D. A.; Wilson, J. A.; Konno, Eddy S.

In: Journal of Mammalogy, Vol. 86, No. 2, 01.04.2005, p. 265-274.

Research output: Contribution to journalArticle

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