Ozsanlav-Harris Luke, Hilton Geoff M, Griffin Larry R, Walsh Alyn J, Cao Lei, Weegman Mitch D, Bearhop Stuart
Centre for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn UK.
Wildfowl & Wetlands Trust Gloucester UK.
Ecol Evol. 2023 Jul 14;13(7):e10281. doi: 10.1002/ece3.10281. eCollection 2023 Jul.
Researchers generally ascribe demographic drivers in a single sub-population and presume they are representative. With this information, practitioners implement blanket conservation measures across metapopulations to reverse declines. However, such approaches may not be appropriate in circumstances where sub-populations are spatiotemporally segregated and exposed to different environmental variation. The Greenland White-fronted Goose, , is an Arctic-nesting migrant that largely comprises two sub-populations (delineated by northerly and southerly breeding areas in west Greenland). The metapopulation has declined since 1999 but this trend is only mirrored in one sub-population and the causes of this disparity are unclear. Here we compare the drivers and trends of productivity in both sub-populations using population- and individual-level analysis. We examined how temperature and precipitation influenced population-level reproductive success over 37 years and whether there was a change in the relationship when metapopulation decline commenced. In addition, we used biologging devices to remotely classify incubation events for 86 bird-years and modelled how phenology and environmental conditions influenced individual-level nest survival. Correlations between reproductive success and temperature/precipitation on the breeding grounds have weakened for both sub-populations. This has resulted in lower reproductive success for the northerly, but not southerly breeding sub-population, which at the individual-level appears to be driven by lower nest survival. Earlier breeding ground arrival and less precipitation during incubation increased nest survival in the northerly breeding population, while no factors examined were important for the southerly breeding sub-population. This suggests reproductive success is driven by different factor(s) in the two sub-populations. Demographic rates and their environmental drivers differ between the sub-populations examined here and consequently we encourage further decomposition of demography within metapopulations. This is important for conservation practitioners to consider as bespoke conservation strategies, targeting different limiting factors, may be required for different sub-populations.
研究人员通常将人口统计学驱动因素归因于单一亚种群，并假定它们具有代表性。基于这些信息，从业者在集合种群中实施全面的保护措施以扭转种群数量的下降。然而，在亚种群在时空上隔离并面临不同环境变化的情况下，这种方法可能并不合适。格陵兰白额雁是一种在北极筑巢的候鸟，主要由两个亚种群组成（由西格陵兰的北部和南部繁殖区域划分）。自1999年以来，该集合种群数量一直在下降，但这种趋势仅在一个亚种群中出现，这种差异的原因尚不清楚。在这里，我们使用种群和个体水平分析来比较两个亚种群生产力的驱动因素和趋势。我们研究了温度和降水如何在37年中影响种群水平的繁殖成功率，以及在集合种群数量下降开始时这种关系是否发生了变化。此外，我们使用生物记录设备对86个鸟类年份的孵化事件进行远程分类，并模拟物候和环境条件如何影响个体水平的巢穴存活率。两个亚种群在繁殖地的繁殖成功率与温度/降水之间的相关性都有所减弱。这导致北部繁殖亚种群的繁殖成功率较低，但南部繁殖亚种群并非如此，在个体水平上，这似乎是由较低的巢穴存活率驱动的。繁殖地更早到达和孵化期间降水减少提高了北部繁殖种群的巢穴存活率，而所研究的因素对南部繁殖亚种群并不重要。这表明两个亚种群的繁殖成功率是由不同因素驱动的。这里所研究的亚种群之间的人口统计学比率及其环境驱动因素不同，因此我们鼓励在集合种群内部进一步分解人口统计学。这对于保护从业者来说很重要，因为可能需要针对不同亚种群制定针对不同限制因素的定制保护策略。
