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No evidence for rapid evolution of seed dispersal ability in range edge populations of the invasive species S enecio madagascariensis
Author(s) -
Bartle Karen,
Moles Angela T.,
Bonser Stephen P.
Publication year - 2013
Publication title -
austral ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.688
H-Index - 87
eISSN - 1442-9993
pISSN - 1442-9985
DOI - 10.1111/aec.12032
Subject(s) - biological dispersal , biology , range (aeronautics) , seed dispersal , seed dispersal syndrome , ecology , germination , diaspore (botany) , population , botany , demography , materials science , sociology , composite material
Theory suggests that range edge populations of invading plants and animals may experience runaway selection for increased dispersal ability. This theory has been supported by field data for cane toads in A ustralia, and for S enecio inaequidens in Europe. In this study, we asked whether range edge populations of S enecio madagascariensis ( A steraceae), an invasive plant in eastern A ustralia, displayed higher dispersal ability that did populations from the established range. We measured 1363 diaspores from 33 populations. There was no significant difference in dispersal potential between populations from the range edge, and those from the established range ( P = 0.19). We also used a glasshouse study to determine whether the range edge populations differed from populations in the established range in three critical life history traits: germination success, plant size and time to first reproduction. The only significant difference was for higher germination in range edge populations. The null result for dispersal ability is excellent news for land managers, as this is the first published evidence that selection for ever‐increasing dispersal rates is not ubiquitous in invading populations.