Maturity Matters

In "Maternal Age is a determinant of larval growth and survival in a marine fish, Sebastes melanops," scientists Steven Berkeley,* Colin Chapman* (Oregon State University) and Susan Sogard (National Marine Fisheries Service) studied larvae from 20 female black rockfish (Sebastes melanops). Their experiment showed that larvae from the oldest female rockfish not only grew up to three times faster than offspring from younger mothers, but also survived starvation for a longer time period. The authors suggest that changes in age-structure due to heavy fishing may "have severe consequences for long-term sustainability of fish populations."

*Berkeley currently at University of California, Santa Cruz; Chapman at S. P. Cramer and Associates, Oregon.

Size Matters

In "Ant body size predicts the dispersal distance of ant-adapted seeds: implications of small-ant invasions" J. H. Ness and J. L. Bronstein (University of Arizona, Tucson), A. N. Anderson (CSIRO Tropical Ecosystems Research Centre, Northern Territory, Australia) and J. N. Holland (Rice University) describe the negative effects invasive smaller ants have on plant reproduction. According to the authors, exotic ants disrupt native ant-seed dispersal patterns, disturbing mutualistic patterns, communities, and ecosystems.

Ecological Monographs

Successful Invasions

Native to Europe, Asia, and North Africa, St. John's wort was first introduced to the United States in 1793 in Lancaster, Pennsylvania, spreading to the West Coast by the early 1900's. By 1945, St. John's Wort became so abundant in the western US it became the first plant in which biocontrol was attempted, through the introduction of a beetle. Yet, not all exotic species introduced become invasive. What makes some exotic species one successful and others fail has never been fully understood.

In an attempt to understand the rol
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Contact: Annie Drinakrd
annie@esa.org
Ecological Society of America
25-May-2004