Data from: Long-lived groupers require structurally stable reefs in the face of repeated climate change disturbances

Benthic recovery from climate-related disturbances does not always warrant a commensurate functional recovery for reef-associated fish communities. Here, we examine the distribution of benthic groupers (family Serranidae) in coral reef communities from the Lakshadweep archipelago (Arabian Sea) in response to structural complexity and long-term habitat stability. These coral reefs that have been subject to two major El Niño Southern Oscillation-related coral bleaching events in the last decades (1998 and 2010). First, we employ a long-term (12-yr) benthic-monitoring dataset to track habitat structural stability at twelve reef sites in the archipelago. Structural stability of reefs was strongly driven by exposure to monsoon storms and depth, which made deeper and more sheltered reefs on the eastern aspect more stable than the more exposed (western) and shallower reefs. We surveyed groupers (species richness, abundance, biomass) in 60 sites across the entire archipelago, representing both exposures and depths. Sites were selected along a gradient of structural complexity from very low to high. Grouper biomass appeared to vary with habitat stability with significant differences between depth and exposure; sheltered deep reefs had a higher grouper biomass than either sheltered shallow or exposed (deep and shallow) reefs. Species richness and abundance showed similar (though not significant) trends. More interestingly, average grouper biomass increased exponentially with structural complexity, but only at the sheltered deep (high stability) sites, despite the availability of recovered structure at exposed deep and shallow sites (lower-stability sites). This trend was especially pronounced for long-lived groupers (life span >10 yrs). These results suggest that long-lived groupers may prefer temporally stable reefs, independent of the local availability of habitat structure. In reefs subject to repeated disturbances, the presence of structurally stable reefs may be critical as refuges for functionally important, long-lived species like groupers

Data from: Long-lived groupers require structurally stable reefs in the face of repeated climate change disturbances

Benthic recovery from climate-related disturbances does not always warrant a commensurate functional recovery for reef-associated fish communities. Here, we examine the distribution of benthic groupers (family Serranidae) in coral reef communities from the Lakshadweep archipelago (Arabian Sea) in response to structural complexity and long-term habitat stability. These coral reefs that have been subject to two major El Niño Southern Oscillation-related coral bleaching events in the last decades (1998 and 2010). First, we employ a long-term (12-yr) benthic-monitoring dataset to track habitat structural stability at twelve reef sites in the archipelago. Structural stability of reefs was strongly driven by exposure to monsoon storms and depth, which made deeper and more sheltered reefs on the eastern aspect more stable than the more exposed (western) and shallower reefs. We surveyed groupers (species richness, abundance, biomass) in 60 sites across the entire archipelago, representing both exposures and depths. Sites were selected along a gradient of structural complexity from very low to high. Grouper biomass appeared to vary with habitat stability with significant differences between depth and exposure; sheltered deep reefs had a higher grouper biomass than either sheltered shallow or exposed (deep and shallow) reefs. Species richness and abundance showed similar (though not significant) trends. More interestingly, average grouper biomass increased exponentially with structural complexity, but only at the sheltered deep (high stability) sites, despite the availability of recovered structure at exposed deep and shallow sites (lower-stability sites). This trend was especially pronounced for long-lived groupers (life span >10 yrs). These results suggest that long-lived groupers may prefer temporally stable reefs, independent of the local availability of habitat structure. In reefs subject to repeated disturbances, the presence of structurally stable reefs may be critical as refuges for functionally important, long-lived species like groupers

Grouper, reef structural complexity and structural stability data from the Lakshadweep archipelago

This dataset is from Karkarey, R., Kelkar, N., Lobo, A.S. et al. Coral Reefs (2014) 33:289–302.DOI 10.1007/s00338-013-1117-

Sequential overgrazing by green turtles causes archipelago-wide functional extinctions of seagrass meadows

After centuries of decline, green turtle (Chelonia mydas) populations are showing handsome localized recoveries due to dedicated conservation efforts. This calls into question how much herbivory can be sustained by seagrass meadows that these turtle populations feed on. In our study, we documented the long-term impacts of green turtle foraging on seagrass meadows in the Lakshadweep archipelago, Indian Ocean. We tracked green turtle densities and seagrass areal extent in five atolls across the archipelago since 2005. Turtle densities first grew to record levels in the seagrass meadow of the Agatti lagoon around 15 years ago. Within a few years of intense herbivory, the meadow underwent radical biomass reduction and compositional shifts, leading to functional extinction and ultimately, bare sand. This trajectory of decline wtas repeated in every atoll, with turtle aggregations persisting 2 to 6 years before meadows were depleted, depending on their initial size. By 2019, all large meadows had declined, and in 2020, green turtles were distributed at low densities in every meadow. The meadows were limited to small patches of early successional species, maintained in a state of protracted recovery by constant, low-level herbivory. We measured the impacts of turtles on two key ecosystem services, a habitat for fish communities and stored organic carbon. Turtle overgrazing resulted in massive declines in seagrass fish diversity, biomass, and abundance, and major reductions in sediment-stored carbon. Apart from being important conservation flagships, green turtles are strong ecosystem interactors, and can potentially cause trophic cascades or functional extinction of seagrass ecosystems

Visiones y esferas de paz en el islam árabe clásico

Ana Ruth Vidal, professora a la Universidad de las Palmas de Gran Canaria i investigadora a l'Instituto de la Paz y los Conflictos de Granada, fa una panoràmica històrica de les diverses esferes de pau que hi ha hagut en la història aràbico-islàmica durant el període clàssic, coincident amb l'Edat mitjana europe

Changing role of coral reef marine reserves in a warming climate

Coral reef ecosystems are among the first to fundamentally change in structure due to climate change, which leads to questioning of whether decades of knowledge regarding reef management is still applicable. Here we assess ecological responses to no-take marine reserves over two decades, spanning a major climate-driven coral bleaching event. Pre-bleaching reserve responses were consistent with a large literature, with higher coral cover, more species of fish, and greater fish biomass, particularly of upper trophic levels. However, in the 16 years following coral mortality, reserve effects were absent for the reef benthos, and greatly diminished for fish species richness. Positive fish biomass effects persisted, but the groups of fish benefiting from marine reserves profoundly changed, with low trophic level herbivores dominating the responses. These findings highlight that while marine reserves still have important roles on coral reefs in the face of climate change, the species and functional groups they benefit will be substantially altered