• Energy Research

Populations of fishes provide valuable services for billions of people, but face diverse and interacting threats that jeopardize their sustainability. Human population growth and intensifying resource use for food, water, energy and goods are compromising fish populations through a variety of mechanisms, including overfishing, habitat degradation and declines in water quality. The important challenges raised by these issues have been recognized and have led to considerable advances over past decades in managing and mitigating threats to fishes worldwide. In this review, we identify the major threats faced by fish populations alongside recent advances that are helping to address these issues. There are very significant efforts worldwide directed towards ensuring a sustainable future for the world's fishes and fisheries and those who rely on them. Although considerable challenges remain, by drawing attention to successful mitigation of threats to fish and fisheries we hope to provide the encouragement and direction that will allow these challenges to be overcome in the future.

Synopsis Climate change will disrupt biological processes at every scale. Ecosystem functions and services vital to ecological resilience are set to shift, with consequences for how we manage land, natural resources, and food systems. Increasing temperatures cause morphological shifts, with concomitant implications for biomechanical performance metrics crucial to trophic interactions. Biomechanical performance, such as maximum bite force or running speed, determines the breadth of resources accessible to consumers, the outcome of interspecific interactions, and thus the structure of ecological networks. Climate change-induced impacts to ecosystem services and resilience are therefore on the horizon, mediated by disruptions of biomechanical performance and, consequently, trophic interactions across whole ecosystems. Here, we argue that there is an urgent need to investigate the complex interactions between climate change, biomechanical traits, and foraging ecology to help predict changes to ecological networks and ecosystem functioning. We discuss how these seemingly disparate disciplines can be connected through network science. Using an ant-plant network as an example, we illustrate how different data types could be integrated to investigate the interaction between warming, bite force, and trophic interactions, and discuss what such an integration will achieve. It is our hope that this integrative framework will help to identify a viable means to elucidate previously intractable impacts of climate change, with effective predictive potential to guide management and mitigation.

AbstractLong‐term records of benthic macroinvertebrates in high‐latitude streams are essential for understanding climatic changes, including extreme events (e.g. floods). Data extending over multiple decades are typically scarce. Here, we investigated macroinvertebrate community structural change (including alpha and beta diversity and gain and loss of species) over 22 years (1994–2016) in 10 stream systems across Denali National Park (Alaska, USA) in relation to climatological and meteorological drivers (e.g. air temperature, snowpack depth, precipitation). We hypothesised that increases in air temperature and reduced snowpack depth, due to climatic change, would reduce beta and gamma diversity but increase alpha diversity. Findings showed temporal trends in alpha diversity were variable across streams, with oscillating patterns in many snowmelt‐ and rainfall runoff‐fed streams linked to climatic variation (temperature and precipitation), but increased over time in several streams supported by a mixture of water sources, including more stable groundwater‐fed streams. Beta‐diversity over the time series was highly variable, yet marked transitions were observed in response to extreme snowpack accumulation (1999–2000), where species loss drove turnover. Gamma diversity did not significantly increase or decrease over time. Investigating trends in individual taxa, several taxa were lost and gained during a relative constrained time period (2000–2006), likely in response to climatic variability and significant shifts in instream environmental conditions. Findings demonstrate the importance of long‐term biological studies in stream ecosystems and highlight the vulnerability of high‐latitude streams to climate change.

Le défi mondial consistant à nourrir deux milliards de personnes supplémentaires d'ici 2050, en utilisant des pratiques agricoles plus durables tout en faisant face aux incertitudes liées aux changements environnementaux, nécessite une transformation des systèmes alimentaires. Nous présentons une nouvelle perspective sur la façon dont les progrès de la science des réseaux peuvent fournir de nouvelles façons de mieux comprendre, exploiter et restaurer de multiples processus écologiques dans les environnements agricoles. Nous décrivons : (i) un cadre axé sur les réseaux pour la gestion des agro-écosystèmes qui tient compte des multiples interactions entre la biodiversité et les services écosystémiques associés ; (ii) des conseils pour intégrer les facteurs socio-économiques dans les réseaux écologiques ; et (iii) le potentiel d'améliorer les méthodes de réseau pour éclairer les efforts visant à renforcer la résilience, y compris les chaînes mondiales d'approvisionnement alimentaire. Ce faisant, nous visons à faciliter l'application de la science des réseaux en tant que moyen basé sur les systèmes pour relever les défis d'assurer une distribution équitable de la nourriture. El desafío global de alimentar a dos mil millones de personas más para 2050, utilizando prácticas agrícolas más sostenibles y lidiando con las incertidumbres asociadas con el cambio ambiental, requiere una transformación de los sistemas alimentarios. Presentamos una nueva perspectiva sobre cómo los avances en la ciencia de redes pueden proporcionar formas novedosas de comprender, aprovechar y restaurar mejor múltiples procesos ecológicos en entornos agrícolas. Describimos: (i) un marco centrado en la red para la gestión de agroecosistemas que tiene en cuenta las múltiples interacciones entre la biodiversidad y los servicios ecosistémicos asociados; (ii) orientación para incorporar factores socioeconómicos en las redes ecológicas; y (iii) el potencial de ampliar los métodos de red para informar los esfuerzos para desarrollar la resiliencia, incluidas las cadenas mundiales de suministro de alimentos. Al hacerlo, nuestro objetivo es facilitar la aplicación de la ciencia de redes como una forma basada en sistemas para abordar los desafíos de garantizar una distribución equitativa de los alimentos. The global challenge of feeding two billion more people by 2050, using more sustainable agricultural practices whilst dealing with uncertainties associated with environmental change, requires a transformation of food systems. We present a new perspective for how advances in network science can provide novel ways to better understand, harness, and restore multiple ecological processes in agricultural environments. We describe: (i) a network-focused framework for managing agro-ecosystems that accounts for the multiple interactions between biodiversity and associated ecosystem services; (ii) guidance for incorporating socio-economic factors into ecological networks; and (iii) the potential to upscale network methods to inform efforts to build resilience, including global food-supply chains. In doing so we aim to facilitate the application of network science as a systems-based way to tackle the challenges of securing an equitable distribution of food. يتطلب التحدي العالمي المتمثل في إطعام ملياري شخص إضافي بحلول عام 2050، باستخدام ممارسات زراعية أكثر استدامة مع التعامل مع الشكوك المرتبطة بالتغير البيئي، تحويل النظم الغذائية. نقدم منظورًا جديدًا لكيفية توفير التقدم في علم الشبكات لطرق جديدة لفهم وتسخير واستعادة العمليات البيئية المتعددة في البيئات الزراعية بشكل أفضل. نحن نصف: (1) إطار عمل يركز على الشبكة لإدارة النظم الإيكولوجية الزراعية التي تمثل التفاعلات المتعددة بين التنوع البيولوجي وخدمات النظم الإيكولوجية المرتبطة به ؛ (2) إرشادات لدمج العوامل الاجتماعية والاقتصادية في الشبكات الإيكولوجية ؛ و (3) إمكانية الارتقاء بأساليب الشبكة لتوجيه الجهود الرامية إلى بناء القدرة على الصمود، بما في ذلك سلاسل الإمدادات الغذائية العالمية. وبذلك نهدف إلى تسهيل تطبيق علم الشبكات كطريقة قائمة على الأنظمة لمواجهة تحديات تأمين التوزيع العادل للغذاء.

AbstractAlpine streams are typically fed from a range of water sources including glacial meltwater, snowmelt, groundwater flow, and surface rainfall runoff. These contributions are projected to shift with climate change, particularly in the Japanese Alps where snow is expected to decrease, but rainfall events increase. The overarching aim of the study was to understand the key variables driving macroinvertebrate community composition in groundwater and snowmelt‐fed streams (n = 6) in the Kamikochi region of the northern Japanese Alps (April–December 2017). Macroinvertebrate abundance, species richness, and diversity were not significantly different between the two stream types. Community structure, however, was different between groundwater and snowmelt‐fed streams with macroinvertebrate taxa specialized for the environmental conditions present in each system. Temporal variation in the abundance, species richness, and diversity of macroinvertebrate communities was also significantly different between groundwater and snowmelt streams over the study period, with snowmelt streams exhibiting far higher levels of variation. Two snowmelt streams considered perennial proved to be intermittent with periodic drying of the streambed, but the macroinvertebrates in these systems rebounded rapidly after flows resumed with no reduction in taxonomic diversity. These same streams, nevertheless, showed a major reduction in diversity and abundance following periods of high flow, indicating floods rather than periodic drying was a major driver of community structure. This conclusion was also supported from functional analyses, which showed that the more variable snowmelt streams were characterized by taxa with resistant, rather than resilient, life‐history traits. The findings demonstrate the potential for significant turnover in species composition with changing environmental conditions in Japanese alpine stream systems, with groundwater‐fed streams potentially more resilient to future changes in comparison to snowmelt‐fed streams.