harmanpkj/Density-dependence-Soay-sheep: for publication

Description

Abstract

Quantifying trade-offs within populations is important in life-history theory. However, most studies focusing on life-history trade-offs focus on two traits and assume tradeoffs to be static. Our work provides a framework for understanding covariation among multiple traits and how population density influences the traits. Using detailed individual-based data for Soay sheep, we find density strongly shapes life-history tradeoffs and distribution of lifetime reproductive success (LRS). At low density, a trade-off between juvenile survival and growth structures life-history variation whereas at equilibrium density, trade-off between reproduction and juvenile survival is the major structuring axes. Contrary to Lomnicki’s prediction, we find at high density there is little variation in the LRS over the sizes (large juveniles and adults) that contribute to reproduction. Our results advance an understanding of dynamic nature of trade-offs, offer insights into how high density limits diversity of individual life-histories, and have implications for evolution via density-dependent selection.