Browsing by Author "Martinez, Enrique A."

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    Hierarchical analysis of reproductive potential in Mazzaella laminarioides (Gigartinaceae, Rhodophyta)
    (1997) Santelices, Bernabe; Martinez, Enrique A.
    Estimations of reproductive effort in seaweeds are important for evaluation of the effects of ecological parameters on fitness as well as for prediction of colonization capacity and competitive potential. Such estimations must consider several levels of resolution. At the coarsest scale of analysis, fertile blade abundance must be Measured. At a finer level of analysis, cystocarps and tetrasporangial sori must be quantified within blade Populations. At the finest level of analysis, the condition of the spores, including their size, stage of maturation, and germination potential Should be considered. This study tests whether the integration of these various scales of analysis into a single algorithm might improve the estimations Of reproductive potential. Application of this analysis to populations of Mazzaella laminarioides (Bory) Fredericq revealed new patterns of distribution at the three hierarchical levels analyzed and new trends across hierarchical levels. The pattern of distribution of fertile blades in the field is characterized by high spatial and seasonal heterogeneity. The size structure of fertile blades revealed a minimum size necessary to achieve reproductive maturity, and the density per unit area of cystocarpic and tetrasporangial sori was higher in larger blades than in smaller ones. No clear pattern of maturation of reproductive was found within blades when sampled along axes from apex to base and from side to side. At the finest level of analysis. it was found that variation in color of reproductive bodies correlated with different spore morphologies and germination rates, thus suggesting a maturation trend. The resulting algorithm used to estimate reproductive potential integrated information from all three levels of analysis. Reduction of variability by making assumptions of homogeneous germination potential, homogeneous blade sizes, or homogeneous spatio-temporal distribution significantly influenced estimates of the number of spores produced per unit area of habitat.