Predicting the viability of species exposed to increasing climatic stress requires an appreciation for the mechanisms underpinning the success or failure of marginal populations. Rather than traditional metrics of long-term population performance, here we illustrate that short-term (i.e., transient) demographic characteristics, including measures of resistance, recovery, and compensation, are fundamental in the poleward range expansion of hard corals, facilitating the establishment of coral populations at higher latitudes. Through the annual census of tropical and subtropical Acropora spp. colonies in Japan between 2017-2019, we show how enhanced transient amplification (i.e., short-term increases in population growth following disturbance) supports the persistence of coral assemblages within more variable high-latitude environments. The transient dynamics of both the tropical and subtropical assemblages were strongly influenced by their corresponding recruitment patterns. However, we demonstrate that variation in colony survival and fragmentation patterns between the two assemblages determines their relative capacities for transient amplification. This latitudinal variation in the transient dynamics of Acropora spp. assemblages emphasises that coral populations can possess the demographic plasticity necessary for exploiting more variable, marginal conditions.

This dataset was collected through the repeated annual survey of tagged Acropora colonies within tropical (Okinawa) and subtropical regions (Kochi) of southern Japan, between 2017 and 2019. Across these surveys we documented colony survival, growth, fragmentation, and the size of newly appearing recruits.

The dataset is comprised of tagged colony metadata, specifically location (Country, Ecoregion, Site), Colony ID, timing of initial tagging, Species identity (Genus, species, etc.), and life-history classification. Next the datafile contains successive size estimates obtained for tagged colonies, however the data is not longitudinal, and so yearly entries for the same individual are entered on seperate rows. Therefore, each row contains each colonies size in the previous year (time.t), its bleaching state, and whether it was a product of fragmentation, the colonies size in the following year (time.t+1), its new bleaching state, and whether it had undergone fragmentation is then recorded. The row also details whether each entry corresponds with a new fragement or recruit colony (in which case colony size for the previous year is entered as NA). If a colony entry has a size entry for time.t but no entry for time.t+1 then the colony is considered dead.

This demographic data was used to parameterise demographic models describing the transient (i.e., short-term) dynamics of tropical and subtropical Acropora assemblage. The functions used to construct these models can be accessed through the PADRINO database, a respository for demographic models. All data analysis and model parameterisation was carried out using Rstudio.

Finally, data describing patterns in Acropora recruitment (e.g. fecundity and settlement) were also used in the construction of our demographic models. These data are not deposisted here as they are part of existing publications. Details on the data used to quantify Acropora settlement are outlined in Nakamura et al. (2015) (https://doi.org/10.3354/meps11525) (contact M. Nakamura for further details). Meanwhile data on Acropora fecundity were sourced from the Coral Trait Database (https://coraltraits.org/), and relate to orginal work by Hall & Hughes 1996 (https://doi.org/10.2307/2265514).