Inferred support for disturbance-recovery hypothesis of North Atlantic phytoplankton blooms

Analyses of satellite-derived chlorophyll data indicate that the phase of rapid phytoplankton population growth in the North Atlantic (the ‘spring bloom') is actually initiated in the winter rather than the spring, contradicting Sverdrup's Critical Depth Hypothesis. An alternative disturbance-recovery hypothesis (DRH) has been proposed to explain this discrepancy, in which the rapid deepening of the mixed layer reduces zooplankton grazing rates sufficiently to initiate the bloom. We use Bayesian parameter inference on a simple Nutrient-Phytoplankton-Zooplankton (NPZ) to investigate the DRH and also investigate how well the model can capture the multiyear and spatial dynamics of phytoplankton concentrations and population growth rates. Every parameter in our NPZ model was inferred as a probability distribution given empirical constraints, this provides a more objective method to identify a model parameterisation given available empirical evidence, rather than fixing or tuning individual parameter values. Our model explains around 75% of variation in the seasonal dynamics of phytoplankton concentrations, 30% of variation in their population rates of change, and correctly predicts the phases of population growth and decline. Our parameter-inferred model supports DRH, revealing the sustained reduction of grazing due to mixed layer deepening as the driving mechanism behind bloom initiation, with the relaxation of nutrient limitation being another contributory mechanism. Our results also show that the continuation of the bloom is caused in part by the maintenance of phytoplankton concentrations below a level that can support positive zooplankton population growth. Our approach could be employed to formally assess alternative hypotheses for bloom formatio

Non-linear changes in modelled terrestrial ecosystems subjected to perturbations

Perturbed ecosystems may undergo rapid and non-linear changes, resulting in ‘regime shifts’ to an entirely different ecological state. The need to understand the extent, nature, magnitude and reversibility of these changes is urgent given the profound effects that humans are having on the natural world. General ecosystem models, which simulate the dynamics of ecosystems based on a mechanistic representation of ecological processes, provide one novel way to project ecosystem changes across all scales and trophic levels, and to forecast impact thresholds beyond which irreversible changes may occur. We model ecosystem changes in four terrestrial biomes subjected to human removal of plant biomass, such as occurs through agricultural land-use change. We find that irreversible, non-linear responses commonly occur where removal of vegetation exceeds 80% (a level that occurs across nearly 10% of the Earth’s land surface), especially for organisms at higher trophic levels and in less productive ecosystems. Very large, irreversible changes to ecosystem structure are expected at levels of vegetation removal akin to those in the most intensively used real-world ecosystems. Our results suggest that the projected twenty-first century rapid increases in agricultural land conversion may lead to widespread trophic cascades and in some cases irreversible changes to ecosystem structure

Differing marine animal biomass shifts under 21st century climate change between Canada's three ocean

Identificadors digitals: Digital object identifier for the 'European Research Council' (http://dx.doi.org/10.13039/501100000781) and Digital object identifier for 'Horizon 2020' (http://dx.doi.org/10.13039/501100007601)Unidad de excelencia María de Maeztu CEX2019-000940-MUnder climate change, species composition and abundances in high-latitude waters are expected to substantially reconfigure with consequences for trophic relationships and ecosystem services. Outcomes are challenging to project at national scales, despite their importance for management decisions. Using an ensemble of six global marine ecosystem models we analyzed marine ecosystem responses to climate change from 1971 to 2099 in Canada's Exclusive Economic Zone (EEZ) under four standardized emissions scenarios. By 2099, under business-as-usual emissions (RCP8.5) projected marine animal biomass declined by an average of −7.7% (±29.5%) within the Canadian EEZ, dominated by declines in the Pacific (−24% ± 24.5%) and Atlantic (−25.5% ± 9.5%) areas; these were partially compensated by increases in the Canadian Arctic (+26.2% ± 38.4%). Lower emissions scenarios projected successively smaller biomass changes, highlighting the benefits of stronger mitigation targets. Individual model projections were most consistent in the Atlantic and Pacific, but highly variable in the Arctic due to model uncertainties in polar regions. Different trajectories of future marine biomass changes will require regional-specific responses in conservation and management strategies, such as adaptive planning of marine protected areas and species-specific management plans, to enhance resilience and rebuilding of Canada's marine ecosystems and commercial fish stocks

Next-generation ensemble projections reveal higher climate risks for marine ecosystems

Projections of climate change impacts on marine ecosystems have revealed long-term declines in global marine animal biomass and unevenly distributed impacts on fisheries. Here we apply an enhanced suite of global marine ecosystem models from the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish-MIP), forced by new-generation Earth system model outputs from Phase 6 of the Coupled Model Intercomparison Project (CMIP6), to provide insights into how projected climate change will affect future ocean ecosystems. Compared with the previous generation CMIP5-forced Fish-MIP ensemble, the new ensemble ecosystem simulations show a greater decline in mean global ocean animal biomass under both strong-mitigation and high-emissions scenarios due to elevated warming, despite greater uncertainty in net primary production in the high-emissions scenario. Regional shifts in the direction of biomass changes highlight the continued and urgent need to reduce uncertainty in the projected responses of marine ecosystems to climate change to help support adaptation planning

Past and future decline of tropical pelagic biodiversity

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by the National Academy of Sciences in PNAS on 26/05/2020.Available online: https://www.pnas.org/content/pnas/117/23/12891.full.pdfA major research question concerning global pelagic biodiversity remains unanswered: when did the apparent tropical biodiversity depression (i.e., bimodality of latitudinal diversity gradient [LDG]) begin? The bimodal LDG may be a consequence of recent ocean warming or of deep-time evolutionary speciation and extinction processes. Using rich fossil datasets of planktonic foraminifers, we show here that a unimodal (or only weakly bimodal) diversity gradient, with a plateau in the tropics, occurred during the last ice age and has since then developed into a bimodal gradient through species distribution shifts driven by postglacial ocean warming. The bimodal LDG likely emerged before the Anthropocene and industrialization, and perhaps ∼15,000 y ago, indicating a strong environmental control of tropical diversity even before the start of anthropogenic warming. However, our model projections suggest that future anthropogenic warming further diminishes tropical pelagic diversity to a level not seen in millions of years.acceptedVersio

Critical Habitats and Biodiversity: Inventory, Thresholds and Governance

The High Level Panel for Sustainable Ocean Economy (https://oceanpanel.org/) has commissioned a series of “Blue Papers” to explore pressing challenges at the nexus of the ocean and the economy. This paper is part of a series of 16 papers to be published between November 2019 and October 2020. It addresses how multiple human impacts will impact biodiversity underpinning ecosystem services such as marine fisheries, aquaculture, coastal protection and tourism. The paper examines the distribution of marine species and critical marine habitats around the world; analyses trends in drivers, pressures, impacts and response; and establishes thresholds for protecting biodiversity hot spots, and indicators to monitor change. From this scientific base, it assesses the current legal framework and available tools for biodiversity protection, current gaps in ocean governance and management and the implications for achieving a sustainable ocean economy tailored to individual coastal states grouped by social indicators

Potential impacts of climate change on agriculture and fisheries production in 72 tropical coastal communities

Climate change is expected to profoundly affect key food production sectors, including fisheries and agriculture. However, the potential impacts of climate change on these sectors are rarely considered jointly, especially below national scales, which can mask substantial variability in how communities will be affected. Here, we combine socioeconomic surveys of 3,008 households and intersectoral multi-model simulation outputs to conduct a sub-national analysis of the potential impacts of climate change on fisheries and agriculture in 72 coastal communities across five Indo-Pacific countries (Indonesia, Madagascar, Papua New Guinea, Philippines, and Tanzania). Our study reveals three key findings: First, overall potential losses to fisheries are higher than potential losses to agriculture. Second, while most locations (> 2/3) will experience potential losses to both fisheries and agriculture simultaneously, climate change mitigation could reduce the proportion of places facing that double burden. Third, potential impacts are more likely in communities with lower socioeconomic status

Assessing progress towards meeting major international objectives related to nature and nature's contributions to people

In recognition of the importance of nature, its contributions to people and role in underpinning sustainable development, governments adopted a Strategic Plan on Biodiversity 2011-2020 through the Convention on Biological Diversity (CBD) containing 20 "Aichi Biodiversity Targets" and integrated many of these into the Sustainable Development Goals (SDGs) adopted through the United Nations in 2015. Additional multilateral environmental agreements (MEAs) target particular aspects of nature (e.g., Ramsar Convention on Wetlands; Convention on Migratory Species), drivers of biodiversity loss (e.g., Convention on International Trade in Endangered Species of Wild Fauna and Flora), or responses (e.g., World Heritage Convention). These various MEAs provide complementary fora in which governments strive to coordinate efforts to reduce the loss and degradation of nature, and to promote sustainable development. In this chapter, we assess, through a systematic review process and quantitative analysis of indicators, progress towards the 20 Aichi Targets under the Strategic Plan (and each of the 54 elements or components of these targets), targets under the SDGs that are relevant to nature and nature's contributions to people (NCP), and the goals and targets of six other MEAs. We consider the relationships between the SDGs, nature and the contributions of Indigenous Peoples and Local Communities (IPLCs) to achieving the various targets and goals, the impact of progress or lack of it on IPLCs, the reasons for variation in progress, implications for a new Strategic Plan for Biodiversity beyond 2020, and key knowledge gaps.For the 44 SDG targets assessed, including targets for poverty, hunger, health, water, cities, climate, oceans and land (Goals 1, 2, 3, 6, 11, 13, 14, 15), findings suggest that current negative trends in nature will substantially undermine progress to 22 SDG targets and result in insufficient progress to meet 13 additional targets (i.e. 80 per cent (35 out of 44) of the assessed targets) {3.3.2.1; 3.3.2.2}(established but incomplete). Across terrestrial, aquatic and marine ecosystems, current negative trends in nature and its contributions will hamper SDG progress, with especially poor progress expected towards targets on water security, water quality, ocean pollution and acidification. Trends in nature's contributions relevant to extreme event vulnerability, resource access, small-scale food production, and urban and agricultural sustainability are negative and insufficient for achieving relevant targets under SDGs 1, 2, 3, and 11. This has negative consequences for both the rural and urban poor who are also directly reliant on declining resources for consumption and income generation {3.3.2.2}. For a further 9 targets evaluated in SDGs 1, 3 and 11 a lack of knowledge on how nature contributes to targets (4 targets) or gaps in data with which to assess trends in nature (5 targets) prevented their assessment.Fil: Butchart, Stuart. London Metropolitan University; Reino UnidoFil: Miloslavich, Patricia. University of Western Australia; AustraliaFil: Reyers, Belinda. No especifíca;Fil: Galetto, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Subramanian, Suneetha M.. No especifíca;Fil: Adams, Cristina. No especifíca;Fil: Palomo, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: McElwee, Pamela. No especifíca;Fil: Meretsky, Vicky J.. No especifíca;Fil: Morsello, Carla. No especifíca;Fil: Nel, Jeanne. No especifíca;Fil: Lynn Newberry, Teresa. No especifíca;Fil: Pacheco, Diego. No especifíca;Fil: Pyhala, Aili. No especifíca;Fil: Rossi Heras, Sergio. No especifíca;Fil: Roy, Joyashree. No especifíca;Fil: Ruiz-Mallén, Isabel. No especifíca;Fil: Salpeteur, Matthieu. No especifíca;Fil: Santos-Martin, Fernando. No especifíca;Fil: Saylor. Kirk. No especifíca;Fil: Schaffartzik, Anke. No especifíca;Fil: Sitas, Nadia. No especifíca;Fil: Speranza, Ifejika. No especifíca;Fil: Suich, Helen. No especifíca;Fil: Tittensor, Derek. No especifíca;Fil: Carignano, Patricia. No especifíca;Fil: Tsioumani, Elsa. No especifíca;Fil: Whitmee, Sarah. No especifíca;Fil: Wilson, Sarah. No especifíca;Fil: Wyndham, Felice. No especifíca;Fil: Zorondo-Rodriguez, Francisco. No especifíca

Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures

Status, challenges and pathways to the sustainable use of wild species

DATA AVAILABILITY : Data will be made available on request.The use of wild species is extensive in both high- and low-income countries. At least 50,000 wild species are used by billions of people around the world for food, energy, medicine, material, education or recreation, contributing significantly to efforts to achieve the United Nations Sustainable Development Goals. However, overexploitation remains a major threat to many wild species. Ensuring and enhancing the sustainability of use of wild species is thus essential for human well-being and biodiversity conservation. Globally, the use of wild species is increasing due to growing human demand and efficiency, but its sustainability varies and depends on the social-ecological contexts in which the use occurs. Multiple environmental and social (including economic) drivers affect the sustainability of use of wild species, posing major current and future challenges. In particular, climate change has already increased the vulnerability of many uses and is expected to increase it further in the coming decades, while global and illegal trades are, in many cases, key drivers of unsustainability. There is no single “silver bullet” policy to address these and other major challenges in the sustainable use of wild species. Rather, effective policies need to integrate inclusive actions at multiple scales that adopt right-based approaches, pay attention to equitable distribution of access and costs and benefits, employ participatory processes, strengthen monitoring programs, build robust customary or government institutions and support context-specific policies, as well as adaptive management.http://www.elsevier.com/locate/gloenvchahj2023Plant Production and Soil Scienc