Population Ecology

, Volume 50, Issue 2, pp 207–214

Contributions of growth, stasis, and reproduction to fitness in brooding and broadcast spawning marine bivalves

Original Article

DOI: 10.1007/s10144-008-0075-7

Cite this article as:
Ripley, B.J. & Caswell, H. Popul Ecol (2008) 50: 207. doi:10.1007/s10144-008-0075-7


Reproductive modes in marine invertebrates can be generally grouped into two types: those brooding larvae and those broadcast-spawning gametes into the water. We asked if these different life-history strategies differ based on how contribution to fitness is partitioned between growth, stasis, and reproduction. To investigate this question, we used published demographic data on ten diverse species of marine bivalves. We parameterized simple matrix-population models and calculated the sums of elasticities to growth, stasis, and reproduction parameters and plotted the results on triangular axes. We also assessed whether contribution patterns were correlated with reproductive mode and tropical, temperate, or polar environments. We found that some of the broadcast spawners fell in the region of the plot with high elasticities for stasis and that some of the brooders fell in the region of the plot with higher growth and reproduction elasticities than stasis ones. However, instead of a sharp dichotomy, we found a continuum in contributions of stasis parameters with long-lived brooders and short-lived broadcast spawners in the same region of the plot. There was no clear pattern of reproductive mode associated with any particular environment, but we think these preliminary results are intriguing and that further work on comparative demography of marine invertebrates is warranted.


Elasticity Life history Matrix-population model Reproductive strategy 

Supplementary material

10144_2008_75_MOESM1_ESM.doc (58 kb)
Descriptions of parameter estimation (DOC 45 kb)

Copyright information

© The Society of Population Ecology and Springer 2008

Authors and Affiliations

  1. 1.Biology DepartmentWoods Hole Oceanographic InstitutionWoods HoleUSA
  2. 2.Biology DepartmentGrossmont CollegeEl CajonUSA

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