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Full-Text Articles in Pharmacology, Toxicology and Environmental Health
Environmentally Sensitive Life-Cycle Traits Have Low Elasticity: Implications For Theory And Practice, Valery E. Forbes, Mette Olsen, Annemette Palmqvist, Peter Calow
Environmentally Sensitive Life-Cycle Traits Have Low Elasticity: Implications For Theory And Practice, Valery E. Forbes, Mette Olsen, Annemette Palmqvist, Peter Calow
Valery Forbes Publications
The relationships between population growth rate and the life-cycle traits contributing to it are nonlinear and variable. This has made it difficult for ecologists to consistently predict changes in population dynamics from observations on changes in life-cycle traits. We show that traits having a high sensitivity to chemical toxicants tend to have a low elasticity, meaning that changes in them have a relatively low impact on population growth rate, compared to other life-cycle traits. This makes evolutionary sense in that there should be selection against variability in population growth rate. In particular, we found that fecundity was generally more sensitive …
Nonylphenol Stimulates Fecundity But Not Population Growth Rate (Λ) Of Folsomia Candida, T. H. Widarto, P. H. Krogh, Valery E. Forbes
Nonylphenol Stimulates Fecundity But Not Population Growth Rate (Λ) Of Folsomia Candida, T. H. Widarto, P. H. Krogh, Valery E. Forbes
Valery Forbes Publications
The toxicity of nonylphenol (NP) to springtails was pronounced at 40 mg/kg dry weight soil, at which no animals survived. Body length and fecundity were the individual life-history traits significantly stimulated by sublethal concentrations of NP during a 64-day experiment. However, the effects of NP on these traits did not result in a statistically significant increase in population growth rate (λ). Decomposition analysis indicated that fecundity was the main contributor to the (non-significant) changes observed in λ. However, since the elasticity of fecundity was very low, large changes in fecundity resulted in a minimal effect on λ. Juvenile survival had …
Toxicant Impacts On Density-Limited Populations: A Critical Review Of Theory, Practice, And Results, Valery E. Forbes, Richard M. Sibly, Peter Calow
Toxicant Impacts On Density-Limited Populations: A Critical Review Of Theory, Practice, And Results, Valery E. Forbes, Richard M. Sibly, Peter Calow
Valery Forbes Publications
Most natural populations experience some density dependence, and longterm average rates of population growth are likely to be close to zero (i.e., steady state). An essential question, therefore, is how and to what extent do density-dependent effects influence the responses of populations to toxicant impacts? Here we consider three general types of interaction between density dependence and toxicant effects: additive, less than additive, and more than additive. If we know enough about the life-history dynamics of an organism and how its life-history traits are affected by density and toxicant exposure, we should be able to use life-history models to predict …