WA9 Ecotoxicology: Endocrine-disrupting Compounds and Their Impacts at the Population, Community, and Ecosystem Levels
Room 12A/B, Level 4
8:00 AM - 12:00 PM, Wednesday, 12 November 2003
Chair: Willingham, Emily ,
(408) Effects of agrichemicals on the life history and behavior of the streamside salamander, Ambystoma barbouri.
ROHR, J1, ELSKUS, A1, SHEPHERD, B1, CROLWEY, P1, MCCARTHY, T1, NIEDZWIECKI, J, SAGER, T1, SIH, A2, PALMER, B1, 1 UNIVERSITY OF KENTUCKY, LEXINGTON, KY, USA2 UNIVERSITY OF CALIFORNIA, DAVIS, CA, USA
ABSTRACT- We investigated the interactions of environmentally relevant concentrations of contaminants with ecological stressors. First, we examined the effects of 37-day embryo/larval exposure to the agrichemicals atrazine, carbaryl, endosulfan, and octylphenol (nominal concentrations: 4-400, 0.5-50, 0.1-10, 5-500 ppb, respectively) on streamside salamanders, Ambystoma barbouri, in the presence and absence of food. Significant differences from controls are reported and were only found at the highest agrichemical concentrations for all studies. Octylphenol delayed hatching, but none of the agrichemicals significantly affected embryo survival. However, larval survival was reduced by carbaryl, endosulfan, and octylphenol, and growth rates were reduced by endosulfan and octylphenol. Significantly more carbaryl, endosulfan, and octylphenol tanks had larvae with limb deformities. Endosulfan and octylphenol decreased larval activity, and atrazine- and endosulfan-treated salamanders exhibited skittishness in response to a vibration stimulus. Agrichemicals inhibited the decrease in refuge use and increase in activity stimulated by hunger. Further investigations on the effects of atrazine (actual concentrations: 0-200 ppb) and food abundance (limited and unlimited food) were conducted on A. barbouri from embryo to metamorphosis. In general, atrazine did not statistically interact with food abundance, and atrazine concentration was correlated positively with magnitude of effect. Atrazine decreased embryo survival and increased time to hatching and variation in hatching day. This greater hatching variation amplified size variation, facilitating larval cannibalism. Increasing atrazine concentrations decreased refuge use and activity. Both food restriction and atrazine reduced larval growth and metamorph size, despite atrazine having no effect on feeding rates. Food limitation delayed metamorphosis while atrazine shortened the larval period. Because reduced growth and smaller size at metamorphosis can lower terrestrial survival and lifetime reproduction, resource limitations and ecologically realistic concentrations of atrazine have the potential to cause or exacerbate amphibian declines in impacted systems. This research was funded by an EPA STAR grant (R829086).
Key words: behavior, Ambystoma, development, metamorphosis