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Does seed dispersal limit initiation of primary succession in desert playas?
Author(s) -
Fort Kevin P.,
Richards James H.
Publication year - 1998
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.2307/2446506
Subject(s) - diaspore (botany) , biological dispersal , seed dispersal , ecological succession , biology , vegetation (pathology) , ecology , abundance (ecology) , desert (philosophy) , medicine , population , philosophy , demography , pathology , epistemology , sociology
To investigate the initiation of primary succession in a cold‐desert playa‐dune complex, we studied the large‐scale (2000 m) seed (diaspore) dispersal patterns at Mono Lake, California. Seeds of seven of the ten species reaching the barren playa had wind‐dispersal adaptations. Rates of dispersal (numbers of seeds per square metre per day) were as much as three orders of magnitude lower on the playa than in the diverse dune vegetation. However, seed input appeared sufficient to reach potential safe sites on the playa, with a peak input of 66 ± 8 total seeds·m −2 ·d −1 . The smooth playa surface, the virtual absence of aboveground barriers, and the high windspeed environment promote the long‐distance dispersal of seeds (at least 1300 m for Chrysothamnus spp. and at least 700 m for Sarcobatus vermiculatus ). The large spatial scale of sampling revealed a relatively high seed input onto the playa by the dominant pioneer species S. vermiculatus, despite the low abundance of parent vegetation in this region. All of these results implicate low rates of seed entrapment as an obstacle to establishment on this desert playa, rather than a lack of seed input.