Demographics of bleaching in a major Caribbean reef-building coral:Montastraea annularis

Abstract

Abstract. Mass bleaching events have become a major cause of coral decline at a global scale. In the summer/fall of 2005 the northeastern Caribbean experienced a record-breaking sea surface warming that resulted in a prolonged mass bleaching event and significant percent coral cover decline of the principal Caribbean reef-building coral Montastraea annularis. In this study, we measured changes in the vital rates of a M. annularis population before, during, and after the 2005 mass bleaching event; stochastically projected the population with different bleaching regimes using a 100 year horizon; and quantified the population level effect of the bleaching event using a life table response experiment. Size-based transition matrices from 2001-2009 were constructed following 399 colonies through time in 17 permanent photo-transects located in Culebra Island, Puerto Rico. Temporal variation in the population growth rate indicates the population (1) was in demographic equilibrium before the event (k ' 1.0), (2) suffered a significant decline in growth rate for two consecutive years after the event (k , 1.0), and (3) demographically recovered three years after the event (k ' 1.0). Partial tissue mortality due to bleaching caused dramatic colony fragmentation that resulted in a population made up almost entirely of small colonies by 2007 (97% were ,50 cm 2 ). The stochastic simulation indicates that an annual probability of bleaching in excess of 6% would result in a decreasing population (k s , 1.0) with a reduction of more than 54% in colony abundance after 100 years of projection. The life table response experiments reveal that most of the effect that bleaching had on the population growth rate comes from changes in the survivorship of small colonies. Recent trends in population decline, as well as the life history traits of M. annularis, suggest that recovery of affected populations by sexual recruitment alone is unlikely. Our findings indicate that survival of small colonies will determine the viability of the M. annularis populations within the context of rising sea surface temperatures. We conclude that the demography of M. annularis is highly susceptible to bleaching and that its viability is seriously compromised under the predicted global warming scenarios.

Evaluating the causal basis of ecological success within the scleractinia: an integral projection model approach

“…Compared to research in other systems, demographic studies on corals are rare. Only a handful of studies have quantified λ (e.g., Hughes 1984;Hughes and Tanner 2000;Edmunds and Elahi 2007;Edmunds 2011;Hernández-Pacheco et al 2011;Madin et al 2012b), despite longstanding efforts to promote demographic analyses of this important taxon (Connell 1973;Hughes and Jackson 1985;Hughes 1996). The implications of the scarcity of studies on the demography of scleractinian corals are now being felt acutely as biologists focus on determining which corals might function as winners or losers, as well as the causal basis of these outcomes, in an era of strong effects of GCC and OA (Hoegh-Guldberg 2012).…”

An Interdisciplinary Erosion Mitigation Approach for Coral Reef Protection – A Case Study from the Eastern Caribbean

“…Long-term monitoring within CLPNR has shown an alarming 50-80% decline in percent live coral cover since 1997 (Hernández-Delgado, 2010). Indirect evidence suggests that the decline in percent living coral cover may be associated with increased sedimentation resulting from recent land development, deforestation, and lack of mandatory erosion controls (Hernández-Delgado, 2004;Hernández-Delgado et al, 2006) (Figure 2), in combination with fishing pressure, climate change-related sea surface warming, massive coral bleaching, and post-bleaching mortality events (Hernández-Pacheco et al, 2011), as it has been documented elsewhere (Miller et al, 2006(Miller et al, , 2009. …”

“…(Rodríguez, 1981;Gardner et al, 2003, Hawkins andRoberts, 2004;Pandolfi et al, 2005;Miller et al, 2006Miller et al, , 2009. In addition, climate change projections suggest a more challenging future for Caribbean coral reef ecosystems (Hoegh-Guldberg, 1999;Hoegh-Guldberg et al, 2007;Buddemeier et al, 2008Buddemeier et al, , 2010Hernández-Pacheco et al, 2011).…”

“…Hence, erosion mitigation by itself has the singular purpose of reducing sediment delivery to levels that are somewhat closer to background rates. The presently grim condition of most coral reefs in the Caribbean and in Culebra is sufficient to justify curtailing sediment delivery into any reef-bearing water body (Hernández-Delgado, 2010;Hernández-Pacheco et al, 2011). Unfortunately, funding limitations will always restrain the level and extensiveness of erosion control strategies.…”

Unsustainable Land Use, Sediment-Laden Runoff, and Chronic Raw Sewage Offset the Benefits of Coral Reef Ecosystems in a No-Take Marine Protected Area

“…Coral reefs are showing limited recovery (Gardner, Côtè , Gill, Grant et al, 2005), with natural benthic community trajectories favoring dominance by non-reef building corals (Edmunds & Elahi, 2007;. Modeling efforts suggest further coral reef decline in the near future under current trends of environmental and climate-related change (Buddemeier, Jokiel, Zimmerman, Lane et al, 2008;Buddemeier, Lane & Martinich, 2011;Herná ndez-Pacheco, Herná ndez-Delgado & Sabat, 2011;Hoeke, Jokiel, Buddemeier & Brainard, 2011;Freeman, Kleypas & Miller, 2013). This can further compromise ecosystem resilience, functions and services (Veron, Hoegh-Guldberg, Lenton, Lough et al, 2009).…”