Understanding the effect of human-driven changes on population performance of long-lived species

Decomposing variation in population growth into contributions from environment and phenotypes in an age-structured population

Fanie Pelletier,Kelly Moyes,Tim H. Clutton-Brock andTim Coulson

Published online before print June 29, 2011, doi:10.1098/rspb.2011.0827 Proc. R. Soc. B

Here is a new paper that attempts to understand the effect of human-driven changes on population performance of long-lived species. It is not an easy task. It is a real challenge to come to grips with the relative importance of ecological drivers responsible for natural population fluctuations.

The authors used a recently developed approach to decompose the observed fluctuation in population growth of the red deer population on the Isle of Rum into contributions from climate, density and their interaction and to quantify their relative importance. They also quantified the contribution of individual covariates, including phenotypic and life-history traits, to population growth.

Fluctuations in composition in age and sex classes of the population contributed substantially to the population dynamics. Density, climate, birth weight and reproductive status contributed less and approximately equally to the population growth.

The researchers signs off saying “ Our results support the contention that fluctuations in the population's structure have important consequences for population dynamics and underline the importance of including information on population composition to understand the effect of human-driven changes on population performance of long-lived species.