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SPATIAL DISTRIBUTION, SURVIVAL, AND FECUNDITY OF DIOON EDULE (ZAMIACEAE) IN A TROPICAL DECIDUOUS FOREST IN VERACRUZ, MEXICO, WITH NOTES ON ITS HABITAT
Author(s) -
Vovides Andrew P.
Publication year - 1990
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 - 10.1002/j.1537-2197.1990.tb11394.x
Subject(s) - biology , ecology , habitat , biological dispersal , seed dispersal , fecundity , population , endangered species , cycad , survivorship curve , seedling , botany , demography , sociology , genetics , cancer
A natural habitat of the cycad Dioon edule Lindl. in central Veracruz, Mexico is described. Prolonged drought periods and fire are factors contributing to seedling death resulting in a population structure with a reverse ‘J’ or Deevey type III survivorship curve. The cycads exhibited a ‘clumped’ or contagious distribution on shallow soils of the habitat and on rocky outcrops. This distribution was attributed to exclusion by competition from other species for water, soil nutrients, and/or seed dispersal by rodents. Estimated coning frequency varied from 2.8 to 8.8 years in male plants and from 10.0 to 52.0 years in female plants, though shorter intervals are known to occur, especially following exceptionally wet years. Chamberlain's age estimate for D. edule has been confirmed and a life table is presented.