Data from: Effects of breeder turnover and harvest on group composition and recruitment in a social carnivore

1. Breeder turnover can influence population growth in social carnivores through changes to group size, composition, and recruitment.
2. Studies that possess detailed group composition data that can provide insights about the effects of breeder turnover on groups have generally been conducted on species that are not subject to recurrent annual human harvest. We wanted to know how breeder turnover affects group composition and how harvest, in turn, affects breeder turnover in cooperatively breeding gray wolves (Canis lupus Linnaeus 1758).
3. We used noninvasive genetic sampling at wolf rendezvous sites to construct pedigrees and estimate recruitment in groups of wolves before and after harvest in Idaho, USA.
4. Turnover of breeding females increased polygamy and potential recruits per group by providing breeding opportunities for subordinates although resultant group size was unaffected one year after the turnover. Breeder turnover had no effect on the number of nonbreeding helpers per group. After breeding male turnover, fewer female pups were recruited in the new males’ litters. Harvest had no effect on the frequency of breeder turnover.
5. We found that breeder turnover led to shifts in the reproductive hierarchies within groups and the resulting changes to group composition were quite variable and depended on the sex of the breeder lost. We hypothesize that nonbreeding females direct help away from non-kin female pups to preserve future breeding opportunities for themselves. Breeder turnover had marked effects on the breeding opportunities of subordinates and the number and sex ratios of subsequent litters of pups. Seemingly subtle changes to groups, such as the loss of 1 individual, can greatly affect group composition, genetic content, and short-term population growth when the individual lost is a breeder.

1. 繁殖者更替（breeder turnover）可通过改变群居食肉动物的群体规模、组成与招募情况，影响其种群增长。
2. 现有可提供繁殖者更替对群体影响相关见解的详尽群体组成数据研究，大多针对无年度持续性人类猎捕的物种开展。本研究旨在探究合作繁殖灰狼（Canis lupus Linnaeus 1758）中，繁殖者更替如何影响群体组成，而猎捕活动又会反过来对繁殖者更替产生何种作用。
3. 我们在美国爱达荷州的狼育幼集合点（rendezvous sites）开展非侵入式遗传采样，以此构建狼群谱系，并估算猎捕前后各狼群的招募情况。
4. 繁殖雌性的更替会为从属个体提供繁殖机会，进而提升群体内的多配偶制比例与单群体潜在招募个体数量，但更替发生一年后，群体规模并未受到显著影响。繁殖者更替对群体内非繁殖帮手的数量无明显作用。当繁殖雄性发生更替后，新雄性所产幼崽中雌性幼崽的招募比例有所降低。猎捕活动对繁殖者更替的发生频率无显著影响。
5. 本研究发现，繁殖者更替会引发群体内繁殖等级的变动，由此带来的群体组成变化存在显著差异，且取决于丢失的繁殖者的性别。我们提出假说：非繁殖雌性会将抚育行为转向非亲缘雌性幼崽以外的个体，以保留自身未来的繁殖机会。繁殖者更替对从属个体的繁殖机会、后续幼崽的数量与性别比例均具有显著影响。看似细微的群体变动——例如单一个体的丢失——若该个体为繁殖者，便可能对群体组成、遗传构成与短期种群增长产生极强的影响。