Survival and movement of translocated houbara bustards in a mixed conservation area

Abstract

For endangered species that are hunted, the establishment of mixed conservation areas including both hunting zones and sanctuaries to complement translocation actions (i.e. reinforcement) can improve both hunting yields and population sustainability. However, the effects of this type of management on the demography of the exploited species are not well understood. We used multi-event capturerecapture modelling in a population of captive-bred houbara bustards Chlamydotis undulata translocated into a mixed conservation area in Morocco. The specific management practice of our system (hunting regime varying in time and space) led to a quasi-experimental situation that allowed the differentiation of 'natural' from 'hunting-induced' mortality and movement between areas. The analysis uncovered strong asymmetries in both movement and survival that were not only due to direct hunting effects. Firstly, movement probabilities were higher from the sanctuary to the hunting areas than vice versa, even in years without hunting. Secondly, in addition to a direct effect of hunting on mortality in hunting areas, our results uncovered permanent differences in both areas (even outside the hunting period). Overall, our results were consistent with predictions under a source-sink dynamic model but illustrated that mixed conservation areas should not merely be treated as homogeneous systems with spatially heterogeneous hunting pressure but rather as fully heterogeneous systems. The patterns observed may be related to (1) the choice and design of hunting and sanctuary areas by managers, which might not be neutral with respect to habitat quality, or (2) indirect consequences of hunting via an effect on local growth rate and density.

Effects of habitat and livestock on nest productivity of the Asian houbara Chlamydotis macqueenii in Bukhara Province, Uzbekistan

“…Predation by desert monitors contributed 54 % of all nest failures for which the cause was considered known and 63 % of known predation. Although predation of houbara nests by this species has been noted previously (Gubin 2004;Launay et al 1997), predation by foxes and corvids is reported more frequently (Combreau and Launay 1999;Combreau et al 2002;Gubin 2004;Lavee 1988). In our study, only 10 % of known predation was attributable to foxes, and even assuming that foxes may have contributed disproportionately to nests affected by 'unknown' predators (a further 27 % of known predation), monitors remain the primary nest predator.…”

“…The similar levels of nest productivity in S. arbuscula, S. rigida and Astragalus habitats suggest that all three are key and should be protected against further habitat loss or infrastructure development (pipelines, powerlines, roads). Although we were unable to examine nest success in Calligonum habitat, few houbara are encountered in this habitat during the breeding season (Gubin 2004;Koshkin et al 2014). The role of Artemisia-dominated habitat, insufficiently sampled in this study, needs further examination.…”

“…Asian houbara have suffered near extirpation of resident populations in the Arabian Peninsula and major declines across Central Asia, primarily as a consequence of unregulated hunting and trapping during migration and winter (BirdLife International 2014;Riou et al 2011;Tourenq et al 2005), with degradation of breeding habitat considered a further factor (Lavee 1988). To date, the primary conservation response to this circumstance has been to release increasingly large numbers of captive-bred individuals of both Asian and African houbara Chlamydotis undulata to re-establish or reinforce exploited populations (Chargé et al 2014;Hardouin et al 2015;Islam et al 2012). Population supplementation by releases of captive-bred stock may play an important role in houbara conservation (Combreau et al 2005), but captive breeding also incurs certain genetic, disease, temperament and domestication risks (Dolman et al 2015;Frankham 2008;Snyder et al 1996;Williams and Hoffman 2009).…”

“…Asian houbara (hereafter 'houbara') breed across a wide range of landscapes and vegetation types, varying with drainage, landform and substrate, from consolidated sands to clay saltpans (Gubin 2004), and differing in shrub height and composition (Koshkin et al 2014(Koshkin et al , 2016. Nest success of wild houbara has been quantified (Combreau and Launay 1999;Combreau et al 2002;Lavee 1988) and nest micro-site selection investigated (Aghanajafizadeh et al 2012;Yang et al 2003), but whether productivity varies with habitat differences or livestock levels remains unknown.…”

Diet of released captive-bred North-African houbara bustards

“…Stomachs were collected from freshly dead houbara provided by hunters (falconers) who hunt birds that were released in the previous seasons before the hunting period in autumn (Lacroix et al 2003;Hardouin et al 2015). Sampled individuals spent on average 15.2 months in the wild after release (SD=12.45, range 3-58).…”