Age and Sex Ratios in a High-Density Wild Red-Legged Partridge Population

Nadal, Jesús; Ponz, Carolina; Margalida, Antoni (2016). Age and Sex Ratios in a High-Density Wild Red-Legged Partridge Population. PLoS ONE, 11(8), e0159765. Public Library of Science 10.1371/journal.pone.0159765

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The dynamics of a wild red-legged partridge population were examined over a 14-year period in Spain to identify patterns in age and sex ratios in relation to weather parameters, and to assess the importance of these parameters in population dynamics and management. The results gave age ratios of 1.07 (but 2.13 in July counts), juvenile sex ratios of 1.01 and adult sex ratios of 1.47. Overall, 12% more females were hatched and female juvenile mortality was 7.3% higher than in males. Sex differential mortality explains the 19.2% deficit in adult females, which are more heavily predated than males during the breeding period. Accordingly, age ratios are dependent on sex ratios and both are density dependent. Over time, ratios and density changes appear to be influenced by weather and management. When the habitat is well conserved, partridge population dynamics can be explained by a causal chain: weather operates on net primary production, thereby affecting partridge reproduction and predation and, as a result, age and sex ratios in the October population. A reduction in the impact of predation (i.e. the effects of ground predators on eggs, chicks and breeding females) is the key factor to improve the conservation of partridge populations and associated biological processes.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE)
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Conservation Biology

UniBE Contributor:

Margalida, Antoni

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 590 Animals (Zoology)

ISSN:

1932-6203

Publisher:

Public Library of Science

Language:

English

Submitter:

Olivier Roth

Date Deposited:

02 Feb 2017 14:33

Last Modified:

05 Feb 2017 02:11

Publisher DOI:

10.1371/journal.pone.0159765

PubMed ID:

27508503

BORIS DOI:

10.7892/boris.93838

URI:

https://boris.unibe.ch/id/eprint/93838

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