Red-legged partridge Alectoris rufa productivity in relation to weather and land use

Resumen del trabajo presentado al 33rd International Union of Game Biologist Congress and 14th Perdix Symposium, celebrados en Montpellier (Francia) del 22 al 25 de agosto de 2017.Productivity is usually a critical demographic parameter affecting population dynamics in many species. In most species, spatial and temporal variations in breeding success are usually associated to variations in environmental conditions, primarily food abundance. Breeding habitat is usually a good surrogate of environmental conditions, as habitat quality may be the factor guiding spatial variations in food abundance or predation risk, and thus breeding success and productivity. Weather is also an important parameter explaining among and within-year variations in breeding success in many species. The determination of the importance of these different factors in explaining productivity is relevant in the context of conservation management, as some of these factors may be modified by man (like habitat quality), but others may not (like weather). We evaluated the reproductive success of the Red-legged partridge and factors associated with it, based on the analysis of 10519 observations of red-legged partridge adults and chicks. Data was obtained from April to July, in 2010, 2011 and 2012, along 300 car transects in the in the regions of Andalucía and Castilla-La Mancha (Figure 1). We used Generalized Mixed Models with “transect” nested within “year” as a random factor; number of chicks per observation, and the ratio of young to adult as dependent variables; age class, observation date, hatching date, climatic variables (rain and temperature), and land use (vegetation, crop diversity and plot size) as independent variables. Average observed brood size for chicks hatched just a few days prior to observation was 6.6 ± 3.5, whereas the observed clutch size in this species in the study area averages between 10 and 14 eggs. This suggests important mortality just after hatching. Young-to-adult ratio increased with observation date, as number of hatched broods increased (Figure 2); values observed at the end of summer were relatively low compared with those observed in other studies. Furthermore, we found a negative relation of family group size (number of chicks) with hatching date, and eldest age classes; and both dependent variables presented relationships with year, climatic and land use variables. Finally, we discuss these results in relation to agriculture intensification link to habitat changes, and weather links to food availability and energy demands.Peer Reviewe