Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

output of percent change in population growth rate. The ocean-type Chinook salmon model
output (Figure 44) produced the next most extreme response, and coho salmon output (Figure
46) showed the greatest changes in lambda resulting from the pesticide exposures. When
looking for similarities in parameters to explain the ranking, no single life history parameter or
characteristic, such as lifespan, reproductive ages, age distribution, lambda and standard
deviation, or first-year survival show a pattern that matches this consistent output (Appendix 1).
Combining these factors into the transition matrix for each life history and conducting the
sensitivity and elasticity analyses revealed that changes in first-year survival produced the
greatest changes in lambda. While some life history characteristics may lead a population to be
more vulnerable to an impact, the culmination of age structure, survival and reproductive rates as
a whole strongly influences the population-level response.
Figure 44. Percent change in lambda for Ocean-type Chinook salmon following 4 d, 21 d, and 60 d
exposures to carbaryl, carbofuran, and methomyl. Open symbols denote a percent change in
lambda of less than one standard deviation from control population. Closed symbols represent a
percent change in lambda of more than one standard deviation from control population.
416