Data from: Den site selection, pack composition, and reproductive success in endangered African wild dogs

Habitat quality is often assumed to be directly related to increased consumer density, but such assumptions cannot be made without supporting demographic data that indicate improved fitness. Habitat selection might be especially important for denning species, where vulnerable offspring are confined to a single location for extended periods, but the effect of den choice on the reproductive success of denning species is poorly understood. By combining airborne high resolution Light Detection and Ranging (LiDAR) measurements with data on pack composition, we investigated den site selection by endangered African wild dogs in Hluhluwe-iMfolozi Park, South Africa, examining whether habitat selection based on ecological factors resulted in increased litter sizes and thus reproductive success compared with social factors known to be important. Although there was selection for den sites in areas of increased terrain ruggedness and vegetation density, only vegetation density was associated with larger litter sizes and translated into increased reproductive success. Moreover, pack size was only influential when a minimum vegetation density around den sites was achieved, indicating that although social variables have a powerful effect on reproductive success, they are mediated by ecological factors defining habitat quality. Our results demonstrate the importance of distinguishing between density and fitness-based indicators of habitat quality, and how this can affect management actions, particularly for endangered species conservation.

生境质量通常被认为与取食者种群密度提升直接相关，但此类假设必须依托能够反映个体适合度改善的种群统计数据方可成立，否则难以成立。生境选择对穴居物种而言可能尤为关键，因为其脆弱的幼崽会长时间被限制在单一地点，但穴址选择对穴居物种繁殖成功率的影响却鲜为人知。本研究结合机载高分辨率激光雷达（Light Detection and Ranging，LiDAR）测量数据与社群组成数据，对南非赫卢赫卢韦-因弗洛齐公园内濒危的非洲野犬的穴址选择行为展开调查，对比已知具有重要影响的社会因素，探究基于生态因素的生境选择是否能提升窝仔数，进而提升繁殖成功率。尽管研究对象会选择地形崎岖度与植被密度更高的区域作为穴址，但仅有植被密度与更大的窝仔数相关，并最终转化为繁殖成功率的提升。此外，仅当穴址周边达到最低植被密度阈值时，社群规模才会对繁殖成功率产生显著影响，这表明尽管社会变量对繁殖成功率具有强调控作用，但其效应仍由界定生境质量的生态因素所介导。本研究结果凸显了区分基于种群密度与基于适合度的生境质量评价指标的重要性，以及此类区分如何影响管理措施，尤其对濒危物种保护而言意义重大。