Across globe, changes are occurring at the population, community, and ecosystem levels and can be detected by measuring collective and simultaneous responses of species (e.g. fluctuation in abundances, phenology, or in behavioral  aspects, etc.) at those levels - broadly known as “synchrony”. Spatial synchrony, i.e. correlated fluctuations among metapopulations, is often found to be driven by spatially correlated climatic variables of the sites where the populations occur – known as Moran effect (Moran 1953). I demonstrated with statistical models that synchronous rare or common occurrences (which is called as dependence only in the lower or upper tails of joint abundance distribution, respectively) among populations across space were driven by the similar nature of tail-dependence among the environmental drivers across those sites (Ghosh, Sheppard, Holder, et al. 2020). This extended Moran effect, we also found in aphids’ abundance and phenological data, where synchronous early or late emergence was driven by cold winter temperature across sites. Similarly, we also found spatial synchrony with tail-dependence features for planktons. But why should we care about “tail-dependence” in spatial synchrony? Synchrony is important for population dynamics because it influences regional population persistence, stability, and resilience. In a mathematical ecology paper, I showed how tail-dependence in metapopulation synchrony could increase or decrease extinction risk, depending on the model dynamics (Ghosh, Sheppard, and Reuman 2020). For example, simultaneously rare (dependence in the lower tail) abundance across metapopulation sites would pose a higher extinction risk than simultaneously abundant (dependence in the upper tail) populations, despite having the same level of correlations - i.e., overall synchrony. Different populations that co-occur at the same sites, also show interspecific “tail-dependent” synchrony through time and that can be explained by the causal mechanism - having a common limiting environmental factor (Ghosh, Sheppard, Reid, et al. 2020). These works initiate thoughts on how one could focus on the “tails” of simultaneous ecological response to understand the change across ecological levels in the face of changing global environments, especially including the extremes. Want to know more? See our recent findings!