Bro, E., Deldalle, B., Massot, M., Reitz, F. & Selmi, S. 2003: Density dependence of reproductive success in grey partridge Perdix perdix populations in France: management implications. - Wildl. Biol. 9: 93-102.
The understanding of the demographic and ecological mechanisms of population regulation is central in applied ecology, in particular when it comes to managing harvested populations. We document the density dependence of the reproductive success in French grey partridge Perdix perdix populations. We used long-term data collected by the national network monitoring populations with a mere surveillance objective. We investigated a time series spanning 7-14 years for 85 replicate populations by a combined procedure of a regression of reproductive success against density for each population and a metaanalysis of the 85 regression slopes. We avoided two common statistical pitfalls by taking the autocorrelation in time series data into account and by using independent estimates of reproductive success and spring density. The relationship is statistically significant for 10% of the populations, and the meta-analysis of the 85 replicates displays a highly significant pattern (82.3% of the regression slopes being negative). Thus our results both support the existence of a density dependent reproductive success in the grey partridge and moderate the ubiquity of the phenomenon, despite a general trend. We tested whether density dependence occurred through competition or habitat heterogeneity by examining the relationship between the variability of per capita reproductive success and pair density. Our results support both alternative hypotheses depending upon the area of concern. In terms of population and habitat management our findings have implications for hunting interests. The best strategy to maximise the hunting quota when reproductive success is depressed with increased density recommends intermediate values of both pair density and reproductive success, which conciliates hunting interests and conservation objectives. To alleviate density dependence, habitat management should supply limited resources that are homogeneously distributed in space when density dependence operates through competition, and should improve habitat quality of the poorest patches when density dependence operates through habitat heterogeneity.
Key words: autoregression, breeding density, density dependence, France, grey partridge, meta-analysis, Perdix perdix, reproductive success
Elisabeth Bro & François Reitz, Office National de la Chasse et de la Faune Sauvage, Direction des Etudes et de la Recherche, CNERA 'Petite Faune Sédentaire de Plaine', Saint-Benoist, B.P. 20, 78612 Le Perray-en-Yvelines cedex, France - e-mail addresses: elisabeth.bro@oncfs.gouv.fr (Elisabeth Bro); francois.reitz@oncfs.gouv.fr (François Reitz)
Benoît Deldalle, Office National de la Chasse et de la Faune Sauvage, Direction des Etudes et de la Recherche, CNERA 'Petite Faune Sédentaire de Plaine', Saint- Benoist, B.P. 20, 78612 Le Perray-en-Yvelines cedex, France, and Laboratoire d’Ecologie, Université Pierre et Marie Curie - Paris VI, UMR 7526, case 237, 7 quai Saint-Bernard, 75252 Paris cedex 05, France
Manuel Massot & Slaheddine Selmi*, Laboratoire d’Ecologie, Université Pierre et Marie Curie - Paris VI, UMR 7526, case 237, 7 quai Saint-Bernard, 75252 Paris cedex 05, France - e-mail addresses: mmassot@snv.jussieu.fr (Manuel Massot); slaheddine.selmi@fsg.rnu.tn (Slaheddine Selmi)
*Present address: Faculté des Sciences de Gabès, Département des Sciences de la Vie et de la Terre, Route de Médenine, 6029 Gabès, Tunisia
Corresponding author: Elisabeth Bro
Received 18 April 2002, accepted 9 September 2002
Associate Editor: Jan Lindström