Coupling of palaeontological and neontological reef coral data improves forecasts of biodiversity responses under global climatic change.

Lewis A. Jones,Alexander Farnsworth,Sarah-Jane Kelland,Peter A. Allison,Paul J. Valdes,Philip D. Mannion

doi:10.1098/rsos.182111

Abstract

Reef corals are currently undergoing climatically driven poleward range expansions, with some evidence for equatorial range retractions. Predicting their response to future climate scenarios is critical to their conservation, but ecological models are based only on short-term observations. The fossil record provides the only empirical evidence for the long-term response of organisms under perturbed climate states. The palaeontological record from the Last Interglacial (LIG; 125 000 years ago), a time of global warming, suggests that reef corals experienced poleward range shifts and an equatorial decline relative to their modern distribution. However, this record is spatio-temporally biased, and existing methods cannot account for data absence. Here, we use ecological niche modelling to estimate reef corals' realized niche and LIG distribution, based on modern and fossil occurrences. We then make inferences about modelled habitability under two future climate change scenarios (RCP4.5 and RCP8.5). Reef coral ranges during the LIG were comparable to the present, with no prominent equatorial decrease in habitability. Reef corals are likely to experience poleward range expansion and large equatorial declines under RCP4.5 and RCP8.5. However, this range expansion is probably optimistic in the face of anthropogenic climate change. Incorporation of fossil data in niche models improves forecasts of biodiversity responses under global climatic change.

Highlights

Anthropogenic climate change, with projected global warming of 2–4.88C, is the principal challenge of the twenty-first century [1]
Both 9 species abundance and diversity are highest within the tropics, with an equatorial dip, the Last Interglacial (LIG) record shows a poleward shift in occurrence records and species diversity, with both increasing at higher latitudes in the Northern Hemisphere, and a prominent equatorial decline [24,25]
Our results suggest that LIG reef corals might have expanded their poleward ranges during the LIG, but that they did not experience an equatorial decline

Summary

Introduction

Anthropogenic climate change, with projected global warming of 2–4.88C, is the principal challenge of the twenty-first century [1]. Rising sea-surface temperatures (SSTs), associated with global warming, have already generated ecological disturbances and substantial range shifts of marine organisms [2,3,4]. Thermal stress, as a direct result of global warming, has generated unprecedented mass bleaching of reef corals, with three pan-tropical events recorded in the last two decades, leading to a decline in abundance, diversity and habitat structure [5,6,7]. Global warming has led to clear poleward range expansion of some corals [8,9,10,11,12], the evidence for equatorial range retractions is debatable [9,13]. Greater understanding of the range dynamics of reef corals is, critical to their conservation

Methods

Results

Discussion

Conclusion