Skip to main content

Advertisement

Log in

Complex life cycles and density dependence: assessing the contribution of egg mortality to amphibian declines

  • Population Ecology
  • Published:
Oecologia Aims and scope Submit manuscript

Abstract.

In the last decade there has been increasing evidence of amphibian declines from relatively pristine areas. Some declines are hypothesized to be the result of egg mortality caused by factors such as elevated solar UV-B irradiation, chemical pollutants, pathogenic fungi, and climate change. However, the population-level consequences of egg mortality have not been examined explicitly, and may be complicated by density dependence in intervening life-history stages. Here we develop a demographic model for two amphibians with contrasting life-history strategies, Bufo boreas and Ambystoma macrodactylum. We then use the complementary approaches of elasticity and limitation to examine the relationships among stage-specific survival rates, larval-stage density dependence and amphibian population dynamics. Elasticity analyses showed that for a range of density dependence scenarios both species were more sensitive to changes in post-embryonic survival parameters, particularly juvenile survival, than to egg survival, suggesting that mortality of later stages may play an important role in driving declines. Limitation analyses revealed that larval density dependence can dramatically alter the consequences of early mortality, reducing or even reversing the expected population-level effects of egg mortality. Thus, greater focus on later life stages and density dependence is called for to accurately assess how stressors are likely to affect amphibian populations of conservation concern.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to James R. Vonesh.

Additional information

Electronic Publication

Rights and permissions

Reprints and permissions

About this article

Cite this article

Vonesh, J.R., De la Cruz, O. Complex life cycles and density dependence: assessing the contribution of egg mortality to amphibian declines. Oecologia 133, 325–333 (2002). https://doi.org/10.1007/s00442-002-1039-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00442-002-1039-9

Navigation