Tomotani Barbara M, Gienapp Phillip, Beersma Domien G M, Visser Marcel E
Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO Box 50, 6700 AB Wageningen, The Netherlands
Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO Box 50, 6700 AB Wageningen, The Netherlands.
Proc Biol Sci. 2016 Sep 28;283(1839). doi: 10.1098/rspb.2016.1366.
Animals in seasonal environments need to fit their annual-cycle stages, such as moult and migration, in a tight schedule. Climate change affects the phenology of organisms and causes advancements in timing of these annual-cycle stages but not necessarily at the same rates. For migratory birds, this can lead to more severe or more relaxed time constraints in the time from fledging to migration, depending on the relative shifts of the different stages. We tested how a shift in hatch date, which has advanced due to climate change, impacts the organization of the birds' whole annual cycle. We experimentally advanced and delayed the hatch date of pied flycatcher chicks in the field and then measured the timing of their annual-cycle stages in a controlled laboratory environment. Hatch date affected the timing of moult and pre-migratory fattening, but not migration. Early-born birds hence had a longer time to fatten up than late-born ones; the latter reduced their interval between onset of fattening and migration to be able to migrate at the same time as the early-born birds. This difference in time constraints for early- and late-born individuals may explain why early-born offspring have a higher probability to recruit as a breeding bird. Climate change-associated advancements of avian egg-lay dates, which in turn advances hatch dates, can thus reduce the negative fitness consequences of reproducing late, thereby reducing the selection for early egg-laying migratory birds.
生活在季节性环境中的动物需要在紧凑的时间表内安排它们的年度周期阶段，比如换羽和迁徙。气候变化会影响生物的物候，并导致这些年度周期阶段的时间提前，但不一定以相同的速率。对于候鸟来说，这可能导致从雏鸟出飞至迁徙这段时间内的时间限制变得更严格或更宽松，这取决于不同阶段的相对变化。我们测试了因气候变化而提前的孵化日期变化如何影响鸟类整个年度周期的安排。我们在野外通过实验提前和推迟了斑姬鹟雏鸟的孵化日期，然后在可控的实验室环境中测量它们年度周期各阶段的时间。孵化日期影响换羽和迁徙前育肥的时间，但不影响迁徙时间。因此，早出生的鸟比晚出生的鸟有更长的育肥时间；晚出生的鸟缩短了育肥开始到迁徙之间的间隔时间，以便能与早出生的鸟同时迁徙。早出生和晚出生个体在时间限制上的这种差异，可能解释了为什么早出生的后代更有可能成长为繁殖鸟。与气候变化相关的鸟类产卵日期提前，进而使孵化日期提前，因此可以减少繁殖较晚带来的负面适应性后果，从而减少对早产卵候鸟的选择。
