Contents lists available at ScienceDirect Global and Planetary Change journal homepage: www.elsevier.com/locate/gloplacha Drivers of shoreline change in atoll reef islands of the Tuamotu Archipelago, French Polynesia Virginie K.E. Duvat a,⁎ , Bernard Salvat b , Camille Salmon a a UMR LIENSs 7266, University of la Rochelle-CNRS, 2 rue Olympe de Gouges, 17000 La Rochelle, France b USR 3278, PSL EPHE-CNRS-UPVD, USR 3278, CRIOBE, Labex Corail, University of Perpignan, France ARTICLE INFO Keywords: Atoll reef islands French Polynesia Shoreline changes Tropical cyclone impacts Anthropogenic disturbances Climate change impacts ABSTRACT This paper increases by around 30% the sample of atoll reef islands studied from a shoreline change perspective, and covers an under-studied geographical area, i.e. the French Tuamotu Archipelago. It brings new irrefutable evidences on the persistence of reef islands over the last decades, as 77% of the 111 study islands exhibited areal stability while 15% and 8% showed expansion and contraction, respectively. This paper also addresses a key research gap by interpreting the major local drivers controlling recent shoreline and island change, i.e. tropical cyclones and seasonal swells, sediment supply by coral reefs and human activities. The 1983 tropical cyclones had contrasting impacts, depending on the shoreline indicator considered. While they generally caused a marked retreat of the stability line, the base of the beach advanced at some locations, as a result of either sediment reworking or fresh sediment inputs. The post-cyclone fair weather period was characterised by reversed trends indicating island morphological readjustment. Cyclonic waves contributed to island upwards growth, which reached up to 1 m in places, through the transfer of sediments up onto the island surface. However, the steep outer slopes of atolls limited sediment transfers to the reef flat and island system. We found that 57% of the study islands are disturbed by human activities, including ‘rural’ and uninhabited islands. Twenty-six percent of these islands have lost the capacity to respond to ocean-climate related pressures, including the ‘capital’ islands concentrating atolls' population, infrastructures and economic activities, which is preoccupying under climate change. 1. Introduction Atoll reef islands are coherent landforms composed of unlithified or poorly consolidated carbonate sediments that have accumulated on coral reef platforms. They are recognized as highly vulnerable to ocean- climate related changes due to their small size (generally < 1 km 2 ), low elevation (< 4–5 m), geomorphic characteristics (poorly con- solidated materials), and high dependency on the sediments supplied by coral reefs (Woodroffe, 2008; Nurse et al., 2014; McLean and Kench, 2015). Consequently, it has commonly been considered that atoll reef islands would disappear under climate change, as a result of sea-level rise and induced accelerating shoreline erosion (Connell, 2003; Dickinson, 2009; McAdam, 2010). Additionally, it is widely acknowl- edged that ocean warming and acidification put a serious threat both on coral reef growth and on the maintenance of reef resources and fresh- water (Gattuso et al., 2015; Karnauskas et al., 2016), leading authors to assume that resource diminution would be likely to force atoll in- habitants to abandon their islands in decades (Hubbard et al., 2014; Storlazzi et al., 2015; Werner et al., 2017). Recent studies assessing shoreline change over the past decades to century have however proved atoll reef island persistence in the face of contemporary sea-level rise (Webb and Kench, 2010; Rankey, 2011; Ford, 2012, 2013; Biribo and Woodroffe, 2013; Ford and Kench, 2015; Kench et al., 2015; Testut et al., 2016; Duvat and Pillet, 2017), there- fore challenging the aforementioned generally accepted idea, and even leading some authors to argue that reef islands would still be there and populated by the end of the 21st century (McLean and Kench, 2015). Additionally, recent reef island studies on shoreline change have highlighted the high variability of change at various spatial and tem- poral scales (Rankey, 2011; Ford, 2012; Ford and Kench, 2015; Mann et al., 2016), and explained it by the major role of local factors, espe- cially climate variability (i.e. tropical cyclones, distant-source swells and ENSO phases) and human activities, in reef island change (Ford, 2012; Biribo and Woodroffe, 2013; Ford and Kench, 2014; Hoeke et al., 2013; Smithers and Hoeke, 2014). Based on the lessons learnt from case studies, they have analysed the implications of understanding past re- cent change for first, apprehending on robust bases reef islands future, and second designing relevant adaptation to climate change strategies http://dx.doi.org/10.1016/j.gloplacha.2017.09.016 Received 9 December 2016; Received in revised form 14 September 2017; Accepted 26 September 2017 ⁎ Corresponding author. E-mail address: virginie.duvat@univ-lr.fr (V.K.E. Duvat). Global and Planetary Change 158 (2017) 134–154 Available online 29 September 2017 0921-8181/ © 2017 Elsevier B.V. All rights reserved. MARK