Corals that survive repeated thermal stress show signs of selection and acclimatization.

Climate change is transforming coral reefs by increasing the frequency and intensity of marine heatwaves, often leading to coral bleaching and mortality. Coral communities have demonstrated modest increases in thermal tolerance following repeated exposure to moderate heat stress, but it is unclear whether these shifts represent acclimatization of individual colonies or mortality of thermally susceptible individuals. For corals that survive repeated bleaching events, it is important to understand how past bleaching responses impact future growth potential. Here, we track the bleaching responses of 1,832 corals in leeward Maui through multiple marine heatwaves and document patterns of coral growth and survivorship over a seven-year period. While we find limited evidence of acclimatization at population scales, we document reduced bleaching over time in specific individuals that is indicative of acclimatization, primarily in the stress-tolerant taxa Porites lobata. For corals that survived both bleaching events, we find no relationship between bleaching response and coral growth in three of four taxa studied. This decoupling suggests that coral survivorship is a better indicator of future growth than is a coral's bleaching history. Based on these results, we recommend restoration practitioners in Hawai'i focus on colonies of Porites and Montipora with a proven track-record of growth and survivorship, rather than devote resources toward identifying and cultivating bleaching-resistant phenotypes in the lab. Survivorship followed a latitudinal thermal stress gradient, but because this gradient was small, it is likely that local environmental factors also drove differences in coral performance between sites. Efforts to reduce human impacts at low performing sites would likely improve coral survivorship in the future.

Closing the gap between existing large-area imaging research and marine conservation needs.

Emerging technology has immense potential to increase the scale and efficiency of marine conservation. One such technology is large-area imaging (LAI), which relies on structure-from-motion photogrammetry to create composite products, including 3-dimensional (3-D) environmental models, that are larger in spatial extent than the individual images used to create them. Use of LAI has become widespread in certain fields of marine science, primarily to measure the 3D structure of benthic ecosystems and track change over time. However, the use of LAI in the field of marine conservation appears limited. We conducted a review of the coral reef literature on the use of LAI to identify research themes and regional trends in applications of this technology. We also surveyed 135 coral reef scientists and conservation practitioners to determine community familiarity with LAI, evaluate barriers practitioners face in using LAI, and identify applications of LAI believed to be most exciting or relevant to coral conservation. Adoption of LAI was limited primarily to researchers at institutions based in advanced economies and was applied infrequently to conservation, although conservation practitioners and survey respondents from emerging economies indicated they expect to use LAI in the future. Our results revealed disconnect between current LAI research topics and conservation priorities identified by practitioners, highlighting the need for more diverse, conservation-relevant research using LAI. We provide recommendations for how early adopters of LAI (typically Global North scientists from well-resourced institutions) can facilitate access to this conservation technology. These recommendations include developing training resources, creating partnerships for data storage and analysis, publishing standard operating procedures for LAI workflows, standardizing methods, developing tools for efficient data extraction from LAI products, and conducting conservation-relevant research using LAI.

Reducción de la brecha entre la investigación actual de imágenes de gran superficie y las necesidades de la conservación marina Resumen Las nuevas tecnologías tienen un enorme potencial para aumentar la escala y la eficiencia de la conservación marina. Una de ellas son las imágenes de gran superficie (IGS), que se basan en la fotogrametría de estructura a partir del movimiento para crear productos compuestos, incluidos modelos ambientales tridimensionales (3D), cuya extensión espacial es mayor que la de las imágenes individuales utilizadas para crearlos. El uso de las IGS se ha generalizado en determinados campos de las ciencias marinas, principalmente para medir la estructura tridimensional de los ecosistemas bentónicos y realizar un seguimiento de los cambios a lo largo del tiempo. Sin embargo, el uso de las IGS en el campo de la conservación marina parece limitado. Realizamos una revisión de la bibliografía sobre el uso de las IGS en los arrecifes de coral para identificar temas de investigación y tendencias regionales en las aplicaciones de esta tecnología. También encuestamos a 135 científicos de arrecifes de coral y profesionales de la conservación para determinar la familiaridad de la comunidad con las IGS, evaluar las barreras a las que se enfrentan los profesionales en el uso de las IGS e identificar sus aplicaciones consideradas como las más interesantes o relevantes para la conservación del coral. La adopción de las IGS se limitó principalmente a los investigadores de las instituciones con sede en las economías avanzadas y se aplicó con poca frecuencia a la conservación, aunque los profesionales de la conservación y los encuestados de las economías emergentes indicaron que esperan utilizar las IGS en el futuro. Nuestros resultados revelaron una desconexión entre los actuales temas de investigación de las IGS y las prioridades de conservación identificadas por los profesionales, lo que subraya la necesidad de una investigación más diversa y relevante para la conservación mediante el uso de las IGS.