Climate variability drives population cycling and synchrony

Abstract

Aim There is mounting concern that climate change will lead to the collapse of cyclic population dynamics, yet the influence of climate variability on population cycling remains poorly understood. We hypothesized that variability in survival and fecundity, driven by climate variability at different points in the life cycle, scales up from local populations to drive regional characteristics of population cycling and spatial synchronization.Location Forest in the US Upper Midwest and Great Lakes region.Methods We tested hypotheses linking variation in vital rates of Ruffed Grouse (Bonasa umbellus), a declining species that displays decadal population cycles, to temperature and precipitation anomalies and land use intensity, using rate estimates from multiple locations in eastern North America. We used climatedemographic linkages to simulate spatially explicit population dynamics from 1982 to 2069, evaluated predictions against monitoring data and assessed predicted population dynamics under future climate projections.Results Nest success and winter survival were linked to temperature and precipitation anomalies, and demographic models explained important spatiotemporal characteristics of cycling and synchrony in monitoring data. The climate-driven vital rates were necessary for cycling and synchrony in models, even though the four included climate variables were not individually periodic. Cycling and synchrony were stronger at more northerly latitudes, but this transition occurred abruptly, reflecting regional variation in winter conditions. Forecasts suggested climate-driven cycling through mid-century, followed by desynchronization and dampening.Main conclusions Climate variability can drive spatio-temporal variation in demographic rates, and population cycling can result from these relationships. Pathways linking climate to broad-scale population dynamics involve responses of vital rates to several climate variables at different times of year and may be more complex than direct responses to known modes of climate variability. The wide-ranging impact of climate change on the demographics of northerly adapted species has the potential to degrade patterns of population synchrony and cycling.

Metapopulation stability in branching river networks

“…This scale-dependent nature of metapopulation stability has been commonly observed in 2D systems (16)(17)(18), where the key theoretical assumption of homogeneous distributions of synchrony may hold true. In those simplified landscapes, two major forces, environmental similarity (i.e., Moran effect) and dispersal, may lead to the emergence of constant synchrony at landscape scales (18)(19)(20).…”

Direct and indirect effects of regional and local climatic factors on trophic interactions in the Arctic tundra

“…Climate effects may occur throughout the life cycle of a species. Cumulative impacts during wintering and breeding seasons may exacerbate the effect of climate variation on species dynamics (Pomara & Zuckerberg, ; Williams et al, ). For instance, the resilience of species to energetic stress in winter and during the subsequent breeding season can be determined by climatic conditions during winter and during post‐winter resource acquisition (Breed, Stichter, & Crone, ; Irwin & Lee, ).…”

Heterogeneous responses of temperate-zone amphibian populations to climate change complicates conservation planning

“…The response of biodiversity to climate change is often examined at macroecological and temporal scales, treating demographic mechanisms implicitly (e.g., 1 , but see 2 ). Demographic rates describe changes in abundance and distribution for populations, but reflect abilities of individual animals to respond to changing conditions and local environments.…”

“…Conversely, if demographic rates of populations are synchronized by large-scale environmental forcing, then adverse change in regional conditions may lead to large-scale population declines. Synchronous responses to climate drivers have been identified for populations of different species over large regions 1 , 2 , 9 , suggesting that the potential exists for a single dominant driver to force synchrony in population dynamics by affecting one or more demographic rates. Furthermore, there is evidence that climatic fluctuations contribute to shifts in demographic processes of populations 10 – 13 , and that climate-mediated declines in animal populations 5 , 14 occur.…”