MULTIPLE STRESSORS AND SALAMANDERS: EFFECTS OF AN HERBICIDE, FOOD LIMITATION, AND HYDROPERIOD

Jason R. Rohr1, Adria A. Elskus, Brian S. Shepherd, Philip H. Crowley, Thomas M. McCarthy, John H. Niedzwiecki, Tyler Sager, Andrew Sih2, and Brent D. Palmer

101 T.H. Morgan Building, Department of Biology, University of Kentucky, Lexington, Kentucky 40506-0225 USA



Amphibian populations can be affected adversely by multiple biotic and abiotic stressors that together can contribute to their local and global decline. We focused on the combined effects of food limitation, drying conditions, and exposure to possibly the most abundant and widely used herbicide in the world, atrazine. We used a factorial design to evaluate the effects of exposure to four ecologically relevant doses of atrazine (approximate measured doses: 0, 4, 40, and 400 μg/L), two food levels (limited and unlimited food), and two hydroperiods (presence or absence of a dry down) on the survival, life history, and behavior of the streamside salamander, Ambystoma barbouri, from the embryo stage through metamorphosis. In general, food and atrazine levels did not interact statistically, and atrazine affected dependent variables in a standard, dose-dependent manner. Exposure to 400 μg/L of atrazine decreased embryo survival and increased time to hatching. Drying conditions and food limitation decreased larval survival, while 400 μg/L of atrazine only reduced larval survival in one of the two years tested, suggesting that the lethality of atrazine may be condition dependent. Sublethal effects included elevated activity and reduced shelter use associated with increasing concentrations of atrazine and food limitation. The larval period was lengthened by food limitation and shortened by 400 μg/L of atrazine. Drying conditions accelerated metamorphosis for larvae exposed to 0 and 4 μg/L of atrazine but did not affect timing of metamorphosis for larvae exposed to 40 or 400 μg/L of atrazine. Food limitation, drying conditions, and 400 μg/L of atrazine reduced size at metamorphosis without affecting body condition (relationship between mass and length), even though feeding rates did not differ significantly among atrazine concentrations at any time during development. This suggests that high atrazine levels may have increased larval energy expenditures. Because smaller size at metamorphosis can lower terrestrial survival and lifetime reproduction, resource limitations, drying conditions, and environmentally realistic concentrations of atrazine have the potential to contribute to amphibian declines in impacted systems.

Keywords: Ambystoma barbouri, amphibian decline, atrazine, behavior, embryos, larvae, life history, metamorphosis, ontogeny, survival

Received: March 21, 2003; Revised: September 18, 2003; Accepted: October 8, 2003

1 E-mail:

2Present address: Department of Environmental Science and Policy, University of California at Davis, California 95616 USA

Cited by

Justin Charles Touchon, Karen Michelle Warkentin. (2009) Negative synergism of rainfall patterns and predators affects frog egg survival. Journal of Animal Ecology 78:4, 715-723
Online publication date: 1-Aug-2009.
CrossRef
TIFFANY S. GARCIA, DAVID J. PAOLETTI, ANDREW R. BLAUSTEIN. (2009) Correlated trait responses to multiple selection pressures in larval amphibians reveal conflict avoidance strategies. Freshwater Biology 54:5, 1066-1077
Online publication date: 1-Jun-2009.
CrossRef
Anne-Lise Mandrillon, Philippe Saglio. (2009) Effects of Single and Combined Embryonic Exposures to Herbicide and Conspecific Chemical Alarm Cues on Hatching and Larval Traits in the Common Frog (Rana temporaria). Archives of Environmental Contamination and Toxicology 56:3, 566-576
Online publication date: 1-May-2009.
CrossRef
Jason R. Rohr, Autumn Swan, Thomas R. Raffel, Peter J. Hudson. (2009) Parasites, info-disruption, and the ecology of fear. Oecologia 159:2, 447-454
Online publication date: 1-Apr-2009.
CrossRef
Jason R.  Rohr, Thomas R.  Raffel, Stanley K.  Sessions, Peter J.  Hudson. (2008) UNDERSTANDING THE NET EFFECTS OF PESTICIDES ON AMPHIBIAN TREMATODE INFECTIONS. Ecological Applications 18:7, 1743-1753
Online publication date: 1-Oct-2008.
Abstract . Full Text . PDF (248 KB) 
Anne-Lise Mandrillon, Philippe Saglio. (2007) Waterborne Amitrole Affects the Predator–Prey Relationship Between Common Frog Tadpoles (Rana temporaria) and Larval Spotted Salamander (Salamandra salamandra). Archives of Environmental Contamination and Toxicology 53:2, 233-240
Online publication date: 1-Sep-2007.
CrossRef
Diane Denise  Forson, Andrew  Storfer. (2006) ATRAZINE INCREASES RANAVIRUS SUSCEPTIBILITY IN THE TIGER SALAMANDER, AMBYSTOMA TIGRINUM. Ecological Applications 16:6, 2325-2332
Online publication date: 1-Dec-2006.
Abstract . Full Text . PDF (130 KB) 
Jason R.  Rohr, Patrick W.  Crumrine. (2005) EFFECTS OF AN HERBICIDE AND AN INSECTICIDE ON POND COMMUNITY STRUCTURE AND PROCESSES. Ecological Applications 15:4, 1135-1147
Online publication date: 1-Aug-2005.
Abstract . Full Text . PDF (170 KB)