Changes in seed dispersal processes and the potential for between-patch connectivity for an arid land daisy

Louise M. Emmerson, José M. Facelli, Peter Chesson, Hugh Possingham, Jemery R. Day

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Dispersal is a major and critical process in population biology that has been particularly challenging to study. Animals can have major roles in seed dispersal even in species that do not appear specifically adapted to animal-aided dispersal. This can occur by two processes: direct movement of diaspores by animals and modification of landscape characteristics by animals in ways that greatly influence dispersal. We exploited the production of large, persistent dispersal structures (seed heads, henceforth) by Erodiophyllum elderi (Asteraceae), a daisy from arid Australia, to further understand secondary dispersal. Seed head dispersal on and off animal tracks in eight E. elderi patches was monitored for 9.5 months by periodically recording the location of marked seed heads. Sites were located inside a reserve that excludes sheep but not kangaroos, and in a nearby area with both kangaroos and sheep. The distance moved and likelihood of seed head movement was higher in areas with sheep, and especially along animal tracks. There was clear evidence that seed heads were channeled down animal tracks during large rainfall events. Seed head dispersal away from patches occurred to a limited extent via their physical contact with sheep and potentially via wind dispersal. Thus, the advantages of this study system allowed us to demonstrate the two postulated effects of herbivores on dispersal via direct movement of seed heads, and two distinct indirect effects through landscape modification by herbivores from the creation of animal tracks and the denudation of vegetation.

Original languageEnglish (US)
Pages (from-to)544-553
Number of pages10
JournalEcology
Volume93
Issue number3
DOIs
StatePublished - Mar 2012

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seed dispersal
arid lands
connectivity
seed
animal
seeds
sheep
animals
Macropodidae
herbivores
herbivore
arid land
diaspore
denudation
Asteraceae
rain
Biological Sciences
vegetation
rainfall

Keywords

  • Aboveground seed bank
  • Asteraceae
  • Erodiophyllum elderi
  • Koonamore daisy
  • Koonamore Station, South Australia
  • Patchy distribution
  • Population dynamics
  • Secondary dispersal
  • Xeric vegetation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

Cite this

Changes in seed dispersal processes and the potential for between-patch connectivity for an arid land daisy. / Emmerson, Louise M.; Facelli, José M.; Chesson, Peter; Possingham, Hugh; Day, Jemery R.

In: Ecology, Vol. 93, No. 3, 03.2012, p. 544-553.

Research output: Contribution to journalArticle

Emmerson, Louise M. ; Facelli, José M. ; Chesson, Peter ; Possingham, Hugh ; Day, Jemery R. / Changes in seed dispersal processes and the potential for between-patch connectivity for an arid land daisy. In: Ecology. 2012 ; Vol. 93, No. 3. pp. 544-553.
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