• Energy Research

Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas.

This data set integrates findings of 16 years (2005 to 2020) of collaborative monitoring efforts across multiple institutions in the Gulf of California.The data encompasses information of 13 species of marine herbivorous fishes belonging to five families: Acanthuridae, Girellidae, Kyphosidae, Pomacentridae and Scaridae. This database presents 884 records of biomass from 15,542 visual censuses assessed by scuba diving in 34 localities (comprising 268 rocky and coral reefs sites). Visual censuses consisted of belt transects (250 m2, 100 m2, and 60 m2) laid parallel to the coastline preserving a similar depth profiles. Along these transects, trained underwater monitors, identified the species, recorded the abundance of all the adult individuals of the 13 targeted species and visually estimated the total length (cm) of each fish. The information for each transect in the database, is presented as the biomass (grams per square meter), which was estimated based on the size per individual as well as the weight-length relationship for each species, available on the literature. In the database is also integrated the information of the latitude and longitude of each locality, type of management, localities in the Gulf of California, institutions, the initial and final year of data, total number of years, as well as the mean, standard deviation, sample size, slope (annual rate of change), probability value, standard error and minimum and maximum value calculated for each species within each locality. This dataset represents a historical reference point for the condition of the 13 species found in the Gulf of California. It can be used to perform evaluations of how herbivorous fish communities have changed over time and across different locations. This is particularly relevant due to the influence of global changes leading to tropicalization in the study area. Furthermore, this information holds significance as it supplies essential insights to those responsible for the management of protected zones in the Gulf and the broader eastern tropical Pacific region. communities have changed over time and across different locations. This is particularly relevant due to the influence of global changes leading to tropicalization in the study area. Furthermore, this information holds significance as it supplies essential insights to those responsible for the management of protected zones in the Gulf and the broader eastern tropical Pacific region. Further funding information:* The work of ECO: Ecosistemas y Conservación was supported by: Fondo Mexicano para la Conservación de la Naturaleza, Award Number: M1901016.* The work of COBI and PANGAS initiative was supported by: Funder: Conservation Leadership Programme.* Niparaja was supported by Fondo Mexicano para la Conservación de la Naturaleza, The David and Lucile Packard Foundation, Walton Family Foundation, Paul M Angell Family Foundation and the Waterloo Foundation. All institutions thank to Comisión Nacional de Áreas Protegidas for support for the development of monitoring in protected áreas.

Climate change, mismanaged resource extraction, and pollution are reshaping global marine ecosystems with direct consequences on human societies. Sustainable ocean development requires knowledge and data across disciplines, scales and knowledge types. Although several disciplines are generating large amounts of data on marine socio-ecological systems, such information is often underutilized due to fragmentation across institutions or stakeholders, limited standardization across scale, time or disciplines, and the fact that information is often not searchable within existing databases. Compiling metadata, the information which describes existing sets of data, is an effective tool that can address these challenges, particularly when metadata corresponding to multiple datasets can be combined to integrate, organize and classify multidisciplinary data. Here, using Mexico as a case study, we describe the compilation and analysis of a metadatabase of ocean knowledge that aims to improve access to information, facilitate multidisciplinary data sharing and integration, and foster collaboration among stakeholders. We also evaluate the knowledge trends and gaps for informing ocean management. Analysis of the metadatabase highlights that past and current research in Mexico focuses strongly on ecology and fisheries, with biological data more consistent over time and space compared to data on human dimensions. Regional imbalances in available information were also evident, with most available information corresponding to the Gulf of California, Campeche Bank and Caribbean and less available for the central and south Pacific and the western Gulf of Mexico. Despite existing knowledge gaps in Mexico and elsewhere, we argue that systematic efforts such as this can often reveal an abundance of information for decision-makers to develop policies that meet key commitments on ocean sustainability. Surmounting current cross-scale social and ecological challenges for sustainability requires transdisciplinary approaches. Metadatabases are critical tools to make efficient use of existing data, highlight and address strengths and deficiencies, and develop scenarios to inform policies for managing complex marine social-ecological systems.

Diadema se encuentra entre los géneros de erizos de mar más abundantes, ampliamente dispersos y ecológicamente importantes en aguas tropicales poco profundas. El mexicanum se distribuye desde el Golfo de California hasta el norte de Perú, incluidas las islas oceánicas de Revillagigedo, Clipperton, Coco, Malpelo y Galápagos, y es una de las especies de erizos de mar más importantes en los arrecifes de coral del Pacífico Oriental Tropical (ETP). En la década de 1980, El Niño causó una alta mortalidad de corales, lo que resultó en un aumento de la cobertura de macroalgas. Esto resultó en una mayor actividad de bioerosión de erizos de mar. que debilitaron los marcos de arrecifes. Considerando la alta vulnerabilidad de los arrecifes de coral ETP, el objetivo de este estudio fue determinar las diferencias regionales en la densidad, el tamaño (diámetro de prueba) y la biomasa de D. mexicanum en 12 localidades en 4 países entre 2009 y 2010, y determinar las posibles causas de estas diferencias. La densidad, el tamaño y la biomasa promedio de D. mexicanum fueron 0.47 ± 0.15 ind.m -2 , 4.38 ± 1.50 cm y 0.26 ± 0.33 g m -2. La frecuencia de tamaño de prueba que predominó fue de 2 a 3 cm. Predicación por macrofagos parece ser uno de los factores más importantes que explican la presencia de bajas densidades y el pequeño tamaño de los erizos de mar en toda la región. El aumento de los depredadores de D. mexicanum es probablemente el resultado de la sobrepesca de los principales depredadores. Diadema est l'un des genres d'oursins les plus abondants, les plus dispersés et les plus importants sur le plan écologique dans les eaux tropicales peu profondes. D. mexicanum est distribué du golfe de Californie au nord du Pérou, y compris les îles océaniques de Revillagigedo, Clipperton, Coco, Malpelo et Galápagos, et c'est l'une des espèces d'oursins les plus importantes dans les récifs coralliens du Pacifique tropical oriental (ETP). Dans les années 1980, El Niño a causé une mortalité corallienne élevée, entraînant une augmentation de la couverture macroallienne. Cela a entraîné une augmentation de l'activité de bioérosion des oursins, considérant la grande vulnérabilité des récifs coralliens de l'ETP, l'objectif de cette étude était de déterminer les différences régionales dans la densité, la taille (diamètre d'essai) et la biomasse de D. mexicanum à 12 localités dans 4 pays entre 2009 et 2010, et de déterminer les causes possibles de ces différences. La densité, la taille et la biomasse moyennes de D. mexicanum étaient de 0,47 ± 0,15 ind.m -2 , 4,38 ± 1,50 cm et 0,26 ± 0,33 g m -2. La fréquence de taille d'essai qui prédominait était de 2 à 3 cm. Prédation par macrophage les poissons semblent être l'un des facteurs les plus importants qui expliquent la présence de faibles densités et de petites tailles d'oursins dans toute la région. L'augmentation des prédateurs de D. mexicanum est probablement le résultat de la surpêche des grands prédateurs. Diadema is among the most abundant, widely dispersed, and ecologically important genera of sea urchin in tropical shallow waters.D. mexicanum is distributed from the Gulf of California to northern Peru, including the oceanic islands of Revillagigedo, Clipperton, Coco, Malpelo, and Galápagos, and it is one of the most important sea urchin species in Eastern Tropical Pacific (ETP) coral reefs.In the 1980s, El Niño caused high coral mortality, resulting in an increase in macroalgal cover.This resulted in higher sea urchin bioerosion activity, which weakened the reef frameworks.Considering the high vulnerability of the ETP coral reefs, the aim of this study was to determine regional differences in the density, size (test diameter), and biomass of D. mexicanum at 12 localities in 4 countries between 2009 and 2010, and to determine possible causes of these differences.The average density, size, and biomass of D. mexicanum were 0.47 ± 0.15 ind.m -2 , 4.38 ± 1.50 cm, and 0.26 ± 0.33 g m -2 .The test size frequency that predominated was 2 to 3 cm.Predation by macrophagous fishes seems to be one of the most important factors that explains the presence of low densities and small size of sea urchins throughout the region.The increase in D. mexicanum predators is probably a result of overfishing of top predators. الدياديما هي من بين أكثر أجناس قنافذ البحر وفرة وانتشارًا على نطاق واسع وأهمية من الناحية البيئية في المياه الضحلة الاستوائية. د. يتم توزيع المكسيكي من خليج كاليفورنيا إلى شمال بيرو، بما في ذلك الجزر المحيطية ريفيلاجيجيدو وكليبرتون وكوكو ومالبيلو وغالاباغوس، وهي واحدة من أهم أنواع قنافذ البحر في الشعاب المرجانية الاستوائية الشرقية في المحيط الهادئ (ETP). في الثمانينيات، تسببت ظاهرة النينيو في ارتفاع معدل وفيات المرجان، مما أدى إلى زيادة في الغطاء الطحالي الكلي. أدى ذلك إلى ارتفاع نشاط التآكل البيولوجي لقنافذ البحر، مما أضعف أطر الشعاب المرجانية. بالنظر إلى الضعف الشديد للشعاب المرجانية ETP، كان الهدف من هذه الدراسة هو تحديد الاختلافات الإقليمية في الكثافة والحجم (قطر الاختبار) والكتلة الحيوية لـ D. mexicanum في 12 موقعًا في 4 دول بين عامي 2009 و 2010، وتحديد الأسباب المحتملة لهذه الاختلافات. كان متوسط الكثافة والحجم والكتلة الحيوية لـ D. mexicanum 0.47 ± 0.15 ind.m -2 و 4.38 ± 1.50 cm و 0.26 ± 0.33 g m -2. كان تردد حجم الاختبار الذي ساد من 2 إلى 3 cm.Predation بواسطة macrophagous يبدو أن الأسماك هي واحدة من أهم العوامل التي تفسر وجود كثافة منخفضة وصغر حجم قنافذ البحر في جميع أنحاء المنطقة. ربما تكون الزيادة في المفترسات المكسيكية ناتجة عن الصيد الجائر للحيوانات المفترسة العليا.