Post Eric, Bøving Pernille Sporon, Higgins R Conor, John Christian, Post Mason, O'Connor Bradyn, Reimer Jesika P, Williamson Nikki, Kerby Jeffrey T
Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA 95616, USA.
Yolo County Resource Conservation District, 221 W Court St, Suite 1, Woodland, CA 95695, USA.
PNAS Nexus. 2025 Jun 6;4(6):pgaf188. doi: 10.1093/pnasnexus/pgaf188. eCollection 2025 Jun.
Long-distance migrants with endogenously timed reproduction may be especially vulnerable to phenological mismatch on summer ranges where offspring are produced and provisioned. In such species, departure timing from winter ranges, and consequently breeding timing on summer ranges, is cued primarily by photoperiod, while local temperature cues the timing of resource availability on summer ranges. Hence, studies of climate change-driven mismatch have focused largely on one aspect of resource phenology: the timing of resource availability on summer ranges. We present a framework for expected reproductive outcomes in long-distance migrants that integrates both seasonal timing and rate of increase in resource availability on summer ranges. The framework predicts that potential disadvantages of earlier resource availability relative to resource demand may be buffered by slow rates of increase in seasonal resource availability. Conversely, potential advantages of later resource availability typical of historically average timing that coincides with the timing of resource demand may be unrealized if resource availability increases too rapidly. We test the framework using 21 years of data on offspring production by tundra caribou, a long-distance migratory breeder whose global abundance is declining, whose timing of reproduction is endogenously entrained, and for whom resource availability on summer ranges may advance with local warming. Agreement with empirical outcomes for caribou, in particular, 3-fold greater offspring production in later springs with slow vegetation green-up compared with later springs with rapid green-up, suggests broader utility of this framework for predicting climate change consequences for phenological match-mismatch in other long-distance migratory breeders.
具有内源性定时繁殖的长途迁徙动物，在其产仔和育雏的夏季栖息地，可能特别容易受到物候不匹配的影响。在这类物种中，从冬季栖息地出发的时间，进而在夏季栖息地的繁殖时间，主要由光周期决定，而当地温度则提示夏季栖息地资源可利用的时间。因此，关于气候变化导致的物候不匹配的研究，主要集中在资源物候的一个方面：夏季栖息地资源可利用的时间。我们提出了一个框架，用于预测长途迁徙动物的繁殖结果，该框架整合了夏季栖息地资源可利用的季节时间和增加速率。该框架预测，相对于资源需求而言，较早的资源可利用性的潜在劣势，可能会被季节性资源可利用性的缓慢增加速率所缓冲。相反，如果资源可利用性增加过快，那么与资源需求时间相吻合的历史平均时间所特有的较晚资源可利用性的潜在优势可能无法实现。我们利用21年的苔原驯鹿产仔数据对该框架进行了测试，苔原驯鹿是一种长途迁徙繁殖动物，其全球数量正在下降，繁殖时间是内源性确定的，并且其夏季栖息地的资源可利用性可能会随着当地变暖而提前。特别是，与植被快速返青的晚春相比，植被返青缓慢的晚春产仔量高出3倍，这与驯鹿的实际情况相符，表明该框架在预测气候变化对其他长途迁徙繁殖动物物候匹配-不匹配的影响方面具有更广泛的实用性。
