Delayed dichromatism in waterfowl as a convenient tool for assessing vital rates
This article has been Reviewed by the following groups
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
- Evaluated articles (Peer Community in Ecology)
Abstract
Monitoring the number of individuals is by far the most popular strategy for studying the environmental factors that determine population dynamics and for measuring the effectiveness of management actions aimed at population recovery, control or eradication. Unfortunately, population size monitoring is inefficient in identifying the mechanisms underlying demographic processes and, in particular, in assessing the extent to which population growth rate is influenced by changes in adult survival rather than variations in reproductive parameters. In many waterfowl species, sexual dichromatism is observed in adults, while immatures of both sexes display a plumage pattern similar to that of adult females. In these species, the apparent proportion of males increases as the female-like immature males gradually take on the plumage of adult males. The difference between the apparent sex ratio before and after the young reach sexual maturity then provides information about the age ratio of a population. Using winter counts that distinguished between female-like and male-like individuals of two non-native populations of Ruddy duck Oxyura jamaicensis , a species that exhibits such a plumage pattern, we present a non-invasive method based on the apparent sex ratio to split population growth rate into adult survival and recruitment rates (the latter also referred to as productivity). This method can correctly detect annual changes in vital rates, supporting the assumption that counts conducted in an appropriate time window reflect the age structure of a population. We exemplify how the respective contributions of survival and productivity to the population growth rate are essential for understanding the processes behind demographic dynamics. Finally, we point out some best practices to correctly apply the ``apparent sex ratio'' method described here.
Article activity feed
-
-
This article highlights a novel non-invasive method based on the "apparent sex ratios" that exploits delayed sexual importance in waterfowl populations. Unlike traditional capture-mark-recapture (CMR) technique, which is costly, invasive, and may disturb the target species, this method infers key population dynamics, such as adult survival rate and recruitment rate, by monitoring sex ratios in counts conducted during winter. Juvenile males that resemble adult females before molting provide a unique opportunity to estimate these vital rates. This method is cost-effective, minimizes disturbance to the species, and is particularly suitable for studying protected or invasive species.
References
Adrien Tableau, Iain Henderson, Sébastien Reeber, Matthieu Guillemain, Jean-François Maillard, Alain Caizergues (2024) Delayed dichromatism in …
This article highlights a novel non-invasive method based on the "apparent sex ratios" that exploits delayed sexual importance in waterfowl populations. Unlike traditional capture-mark-recapture (CMR) technique, which is costly, invasive, and may disturb the target species, this method infers key population dynamics, such as adult survival rate and recruitment rate, by monitoring sex ratios in counts conducted during winter. Juvenile males that resemble adult females before molting provide a unique opportunity to estimate these vital rates. This method is cost-effective, minimizes disturbance to the species, and is particularly suitable for studying protected or invasive species.
References
Adrien Tableau, Iain Henderson, Sébastien Reeber, Matthieu Guillemain, Jean-François Maillard, Alain Caizergues (2024) Delayed dichromatism in waterfowl as a convenient tool for assessing vital rates. bioRxiv, ver.3 peer-reviewed and recommended by PCI Ecology https://doi.org/10.1101/2024.06.04.597326
-
