Using demographic models to project the effects of climate change on scleractinian corals: Pocillopora damicornis as a case study

Abstract

Using empirical analyses of the effects of global climate change (GCC) and ocean acidification (OA) on the survival and calcification of early life stages of Pocillopora damicornis, we employed a demographic approach to forecast the consequences of GCC and OA on the population dynamics of this coral. We constructed a size-based demographic model using life-history tables and transition probabilities for a population in Southern Taiwan, and projected the population structure over ~100 yr under scenarios of warming and acidification. The simulations incorporated stochastic variability of the parameters (±5 %), decline in larval survival due to increases in temperature and pCO2, modified growth rates due to rising temperature, and larval input from distant populations. In a closed population, an increase of pCO2 from 40.5 to 91.2 Pa reduces density, and an increase in temperature from 26 to 29 °C results in population extirpation within 100 yr. With a larval supply of 10 % from distant populations, the population persisted regardless of high temperature (+3 °C). These results indicate that: (1) populations of P. damicornis may be resistant to GCC and OA so long as it persists as part of a metapopulation capable of supplying larvae from spatially separated populations and (2) early life stages can regulate the population dynamics of P. damicornis.