Mine waste disposal leads to lower coral cover, reduced species richness and a predominance of simple coral growth forms on a fringing coral reef in Papua New Guinea M.D.E. Haywood a, * , D. Dennis a , D.P. Thomson b , R.D. Pillans a a CSIRO Oceans and Atmosphere, Queensland Biosciences Precinct, 306 Carmody Rd., St. Lucia, Queensland 4067, Australia b CSIRO Oceans and Atmosphere,147 Underwood Ave, Floreat, Western Australia 6014, Australia article info Article history: Received 12 November 2015 Received in revised form 1 February 2016 Accepted 3 February 2016 Available online 4 February 2016 Keywords: Turbidity Sedimentation Coral Coral reef decline Papua New Guinea abstract A large gold mine has been operating at the Lihir Island Group, Papua New Guinea since 1997. The mine disposes of waste rock in nearshore waters, impacting nearby coral communities. During 2010, 2012 we conducted photographic surveys at 73 sites within 40 km of the mine to document impacts of mining operations on the hard coral communities. Coral communities close to the mine (~2 km to the north and south of the mine) were depaurperate, but surprisingly, coral cover and community composition beyond this range appeared to be relatively similar, suggesting that the mine impacts were limited spatially. In particular, we found mining operations have resulted in a significant decrease in coral cover (4.4% 1.48 km from the disposal site c.f. 66.9% 10.36 km from the disposal site), decreased species richness and a predominance of less complex growth forms within ~2 km to the north and south of the mine waste disposal site. In contrast to the two ‘snapshot’ surveys of corals performed in 2010 and 2012, long term data (1999e2012) based on visual estimates of coral cover suggested that impacts on coral communities may have been more extensive than this. With global pressures on the world's coral reefs increasing, it is vital that local, direct anthropogenic pressures are reduced, in order to help offset the impacts of climate change, disease and predation. Crown Copyright © 2016 Published by Elsevier Ltd. All rights reserved. 1. Introduction Coral reefs worldwide are threatened by multiple stressors including climate change, eutrophication, pollution, ocean acidifi- cation, pathogens, crown-of-thorns starfish and increased turbidity and sedimentation (Ban et al., 2014). Of these, the impacts of increased sediments and nutrients are amongst the most serious with 25% of the world's coral reefs estimated to be under threat from increasing exposure to both sediments and nutrients (Burke et al., 2011). High levels of sedimentation and turbidity may be derived from natural or anthropogenic sources (Erftemeijer et al., 2012). Natural sources of sedimentation include stream discharge (Loya, 1976; Golbuu et al., 2008, 2011), terrestrial runoff after heavy rain (Jokiel et al., 1993; Fabricius et al., 2007) and resuspension of sediments after storms (Dutra et al., 2006). Anthropogenic sources of increased sedimentation include dredging (Rogers, 1983, 1990; Brown et al., 1990; Erftemeijer et al., 2012), mine waste disposal (Risk and Edinger, 2011; Edinger, 2012) and the exacerbation of natural processes through land clearing, over grazing and coastal development (McClanahan and Obura, 1997; Storlazzi et al., 2011). Sedimentation and turbidity impacts corals either directly through smothering or indirectly through reducing the amount of light reaching the coral polyps. Sediment that has settled on the substrate may smother and/or bury corals (Hubbard, 1986; Fabricius and Wolanski, 2000; Philipp and Fabricius, 2003) reducing coral growth rates (Aller and Dodge, 1974), increasing expenditure of energy through sediment removal (Riegl and Branch, 1995), hampering coral larval settlement (Babcock and Davies, 1991) and survival (Sato, 1985) and modifying coral growth forms (Risk and Edinger, 2011; Fabricius et al., 2012). Sus- pended sediments increase turbidity limiting the amount of light available to phototrophic organisms (Loya, 1976; Anthony and Connolly, 2004). This can reduce calcification (Gattuso et al., 1999) and coral fertilization rates (Humphrey et al., 2008) and in- crease the vulnerability of corals to pathogens through reduced vitality (Pollock et al., 2014). * Corresponding author. E-mail address: mick.haywood@csiro.au (M.D.E. Haywood). Contents lists available at ScienceDirect Marine Environmental Research journal homepage: www.elsevier.com/locate/marenvrev http://dx.doi.org/10.1016/j.marenvres.2016.02.003 0141-1136/Crown Copyright © 2016 Published by Elsevier Ltd. All rights reserved. Marine Environmental Research 115 (2016) 36e48