A Life-History Approach to Predicting the Recovery of Aquatic Invertebrate Populations After Exposure to Xenobiotic Chemicals

Abstract

Abstract-A combined empirical and theoretical study was conducted to evaluate the degree to which an understanding of the life histories of different freshwater invertebrate taxa could improve our ability to predict their relative rates of recovery after a toxic perturbation. Two chemicals, cypermethrin and 3,4-dichloroaniline, were introduced separately into large freshwater tanks (mesocosms, 1.25 m diameter, 1.25 m depth) containing established freshwater invertebrate communities. Immigration was simulated in selected mesocosms by introducing particular taxa at predetermined intervals. For both chemical treatments, laboratory rank toxicity data successfully predicted the observed relative short-term mortalities of species, whereas the relative times taken for taxa to recover from cypermethrin exposure also correlated with their relative susceptibilities to this compound. Crucially, a significant component of residual variance in rank recovery to cypermethrin was explained by variation in overall rates of reproduction among taxa. A simulation model was therefore developed to allow us to integrate the disparate information on invertebrate life histories into a predictive model. This model was broadly supported, particularly for the cypermethrin exposure data, where observed and predicted rank recovery times were highly correlated. Overall, this study broadly confirms the importance of life-history characters in governing recovery and the validity of simple modeling approaches for predicting recovery.

Competition matters: Species interactions prolong the long‐term effects of pulsed toxicant stress on populations

“…This assumption is supported by the aforementioned microcosm experiment; indirect effects that originated from the reduction in population density of the sensitive competitor because of contamination increased insensitive Daphniidae abundance after contamination [17]. This is congruent with results from previous studies: in mesocosm communities, the recovery of aquatic invertebrate populations after pesticide exposure was reported to be faster for species with higher reproductive rates [30]. Furthermore, reproduction of Daphnia magna and other Daphnia species is density-dependently reduced under competition for common resources [29].…”

Threshold Levels for Effects of Insecticides in Freshwater Ecosystems: A Review

“…The most sensitive endpoints for direct effects of the insecticides studied were structural ecosystem characteristics and usually concerned population densities of crustaceans and insects. These direct effects can generally be well predicted on the basis of laboratory tests with similar species as studied in the microcosm and mesocosm experiments (e.g., Crossland and Wolff, 1985;Fairchild et al, 1992a;Maund et al, 1998;Sheratt et al, 1999;Schroer et al, 2004). Different studies conducted with the same insecticide (e.g., chlorpyrifos, esfenvalerate, lambda-cyhalothrin) also yield similar critical threshold values (Tables 7 and 9).…”

Pyrethroid Insecticides: Use, Environmental Fate, and Ecotoxicology

“…In general, recovery from pyrethroid exposure is likely to be a function of species-specific sensitivity and reproductive rates. For instance, Sherratt et al (1999) found that recovery times following cypermethrin exposures were longest for the most sensitive taxa and for those with low reproductive rates. Populations of flying, semi-aquatic insects began to re-establish within days of deltamethrin treatment, while abundances of aquatic invertebrates, such as cladocerans and fairy shrimp, were suppressed longer, as recovery was predicated on the number of resting eggs present in the pond environment (Lahr et al, 2000).…”