Résumé
Synchronous variation in demographic parameters across species
destabilizes populations, metapopulations and metacommunities and
increases extinction risks. Revealing the processes that synchronize
population dynamics across species allows us to identify trans-specific
demographic processes that are subject to environmental forcing of
overarching importance. Using a Bayesian, hierarchical multi-site,
multi-species mark-recapture model, we investigated temporal interspecific
synchrony in annual adult local survival across 16 common songbird species
across France for the period 2001–2016. Adult annual survival was largely
synchronous among species (73% [47–94] of the variation among years was
common to all species), despite species differing in ecological niche and
life-histories. This result was robust to differences in migratory
strategy among species, uneven species sample sizes, and time de-trending.
Shared synchrony across migratory strategy suggests that environmental
forcing during the 4-month temperate breeding season has large-scale,
cross-specific, impacts among songbirds. At a scale ~1000 km, a likely
proximate mechanism of synchronization is forcing by weather-driven
variation in resources, which, in particular, determines the cost of
reproduction. However, the strong interspecific synchrony was not easily
explained by a set of a priori defined candidate weather variables, with
spring weather variables explaining only 1.4% [0.01–5.5] of synchrony,
while the contribution of large-scale winter weather indices may be
stronger, but uncertain (12% [0.3–37]). Future research may up-scale these
results to community dynamics, to understand compensatory intra- and
inter-specific demographic processes that preserve meta-communities from
synchronization.