scholarly journals Scientists' warning on endangered food webs

Web Ecology ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Ruben H. Heleno ◽  
William J. Ripple ◽  
Anna Traveset
Keyword(s):  
Climate Change ◽  
Food Webs ◽  
Large Scale ◽  
Biodiversity Loss ◽  
Global Scale ◽  
Natural Food ◽  
Stable States ◽  
Trade Offs ◽  
Over Exploitation ◽  
Increasing Temperature

Abstract. All organisms are ultimately dependent on a large diversity of consumptive and non-consumptive interactions established with other organisms, forming an intricate web of interdependencies. In 1992, when 1700 concerned scientists issued the first “World Scientists' Warning to Humanity”, our understanding of such interaction networks was still in its infancy. By simultaneously considering the species (nodes) and the links that glue them together into functional communities, the study of modern food webs – or more generally ecological networks – has brought us closer to a predictive community ecology. Scientists have now observed, manipulated, and modelled the assembly and the collapse of food webs under various global change stressors and identified common patterns. Most stressors, such as increasing temperature, biological invasions, biodiversity loss, habitat fragmentation, over-exploitation, have been shown to simplify food webs by concentrating energy flow along fewer pathways, threatening long-term community persistence. More worryingly, it has been shown that communities can abruptly change from highly diverse to simplified stable states with little or no warning. Altogether, evidence shows that apart from the challenge of tackling climate change and hampering the extinction of threatened species, we need urgent action to tackle large-scale biological change and specifically to protect food webs, as we are under the risk of pushing entire ecosystems outside their safe zones. At the same time, we need to gain a better understanding of the global-scale synergies and trade-offs between climate change and biological change. Here we highlight the most pressing challenges for the conservation of natural food webs and recent advances that might help us addressing such challenges.

Functional diversity alters the effects of a pulse perturbation on the dynamics of tritrophic food webs

2021 ◽  
Author(s):  
Ruben Ceulemans ◽  
Laurie Anne Myriam Wojcik ◽  
Ursula Gaedke
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Functional Diversity ◽  
Feedback Loop ◽  
Environmental Changes ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Nutrient Pulse ◽  
Trade Offs ◽  
Food Web Model

Biodiversity decline causes a loss of functional diversity, which threatens ecosystems through a dangerous feedback loop: this loss may hamper ecosystems' ability to buffer environmental changes, leading to further biodiversity losses. In this context, the increasing frequency of climate and human-induced excessive loading of nutrients causes major problems in aquatic systems. Previous studies investigating how functional diversity influences the response of food webs to disturbances have mainly considered systems with at most two functionally diverse trophic levels. Here, we investigate the effects of a nutrient pulse on the resistance, resilience and elasticity of a tritrophic---and thus more realistic---plankton food web model depending on its functional diversity. We compare a non-adaptive food chain with no diversity to a highly diverse food web with three adaptive trophic levels. The species fitness differences are balanced through trade-offs between defense/growth rate for prey and selectivity/half-saturation constant for predators. We showed that the resistance, resilience and elasticity of tritrophic food webs decreased with larger perturbation sizes and depended on the state of the system when the perturbation occured. Importantly, we found that a more diverse food web was generally more resistant, resilient, and elastic. Particularly, functional diversity dampened the probability of a regime shift towards a non-desirable alternative state. In addition, despite the complex influence of the shape and type of the dynamical attractors, the basal-intermediate interaction determined the robustness against a nutrient pulse. This relationship was strongly influenced by the diversity present and the third trophic level. Overall, using a food web model of realistic complexity, this study confirms the destructive potential of the positive feedback loop between biodiversity loss and robustness, by uncovering mechanisms leading to a decrease in resistance, resilience and elasticity as functional diversity declines.

scholarly journals Quantifying synergies and trade-offs in the water-land-energy-food-climate nexus using a multi-model scenario approach

2020 ◽  
Author(s):  
Jonathan Doelman ◽  
Tom Kram ◽  
Benjamin Bodirsky ◽  
Isabelle Weindle ◽  
Elke Stehfest
Keyword(s):  
Climate Change ◽  
Sustainable Development ◽  
Food Security ◽  
Food Production ◽  
Large Scale ◽  
Sustainable Development Goals ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Trade Offs ◽  
Development Goals

<p>The human population has substantially grown and become wealthier over the last decades. These developments have led to major increases in the use of key natural resources such as food, energy and water causing increased pressure on the environment throughout the world. As these trends are projected to continue into the foreseeable future, a crucial question is how the provision of resources as well as the quality of the environment can be managed sustainably.</p><p>Environmental quality and resource provision are intricately linked. For example, food production depends on availability of water, land suitable for agriculture, and favourable climatic circumstances. In turn, food production causes climate change due to greenhouse gas emissions, and affects biodiversity through conversion of natural vegetation to agriculture and through the effects of excessive fertilizer and use of pesticides. There are many examples of the complex interlinkages between different production systems and environmental issues. To handle this complexity the nexus concept has been introduced which recognizes that different sectors are inherently interconnected and must be investigated in an integrated, holistic manner.</p><p>Until now, the nexus literature predominantly exists of local studies or qualitative descriptions. This study present the first qualitative, multi-model nexus study at the global scale, based on scenarios simultaneously developed with the MAgPIE land use model and the IMAGE integrated assessment model. The goal is to quantify synergies and trade-offs between different sectors of the water-land-energy-food-climate nexus in the context of sustainable development goals (SDGs). Each scenario is designed to substantially improve one of the nexus sectors water, land, energy, food or climate. A number of indicators that capture important aspects of both the nexus sectors and related SDGs is selected to assess whether these scenarios provide synergies or trade-offs with other nexus sectors, and to quantify the effects. Additionally a scenario is developed that aims to optimize policy action across nexus sectors providing an example of a holistic approach that achieves multiple sustainable development goals.</p><p>The results of this study highlight many synergies and trade-offs. For example, an important trade-off exists between climate change policy and food security targets: large-scale implementation of bio-energy and afforestation to achieve stringent climate targets negatively impacts food security. An interesting synergy exists between the food, water and climate sectors: promoting healthy diets reduces water use, improves water quality and increases the uptake of carbon by forests.</p>

scholarly journals Amphibian Collapses Exacerbated Malaria Outbreaks in Central America

2020 ◽  
Author(s):  
Michael R. Springborn ◽  
Joakim A. Weill ◽  
Karen R. Lips ◽  
Roberto Ibáñez ◽  
Aniruddha Ghosh
Keyword(s):  
Infectious Diseases ◽  
Food Webs ◽  
Central America ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Malaria Incidence ◽  
Biodiversity Loss ◽  
Natural Food ◽  
Estimation Model ◽  
Human Welfare

AbstractEcosystems play an important role in supporting human welfare, including regulating the transmission of infectious diseases. Many of these services are not fully-appreciated due to complex environmental dynamics and lack of baseline data. Multicontinental amphibian decline due to the fungal pathogen Batrachochytrium dendrobatidis (Bd) provides a stark example. Even though amphibians are known to affect natural food webs—including mosquitoes that transmit human diseases—the human health impacts connected to their massive decline have received little attention. Here we show a causal link between a wave of Bd-driven collapse of amphibians in Central America and increased human malaria incidence. At the canton-level in Costa Rica and district-level in Panama, expected malaria incidence increased for eight years subsequent to amphibian losses, peaking at an additional 1.0 cases per 1,000 population (CPK). The increase is substantial in comparison to annual incidence levels from outbreaks in these countries, which peaked at 1.1-1.5 CPK during our period of study from 1976-2016. This pattern holds across multiple alternative approaches to the estimation model. This previously unidentified impact of biodiversity loss illustrates the often hidden human welfare costs of conservation failures. These findings also show the importance of mitigating international trade-driven spread of similar emergent pathogens like Batrachochytrium salamandrivorans.Significance StatementDespite substantial multicontinental collapses in amphibian populations from spread of the fungal pathogen Batrachochytrium dendrobatidis (Bd), the implications for humans have not been systematically studied. Amphibians are known to affect food webs, including mosquitoes that serve as a vector for the spread of disease. However, little is known about how their loss erodes ecosystem services, including the regulation of the transmission of infectious diseases. Using Central America as a case study, this study shows that Bd-driven amphibian loss led to a substantial increase in malaria incidence. The results highlight the often underappreciated social costs of biodiversity loss, including the potential stakes of ecosystem disruption from failing to stop spread of future novel pathogens.

scholarly journals Restoration ecologists might not get what they want: Global change shifts trade-offs among ecosystem functions

2020 ◽  
Author(s):  
Sebastian Fiedler ◽  
José A.F. Monteiro ◽  
Kristin B. Hulvey ◽  
Rachel J. Standish ◽  
Michael P. Perring ◽  
...  
Keyword(s):  
Climate Change ◽  
Plant Species ◽  
Plant Diversity ◽  
Large Scale ◽  
Plant Traits ◽  
Climatic Conditions ◽  
Ecosystem Functions ◽  
List Type ◽  
Trade Offs

ABSTRACTEcological restoration increasingly aims at improving ecosystem multifunctionality and making landscapes resilient to future threats, especially in biodiversity hotspots such as Mediterranean-type ecosystems. Successful realisation of such a strategy requires a fundamental mechanistic understanding of the link between ecosystem plant composition, plant traits and related ecosystem functions and services, as well as how climate change affects these relationships. An integrated approach of empirical research and simulation modelling with focus on plant traits can allow this understanding.Based on empirical data from a large-scale restoration project in a Mediterranean-type climate in Western Australia, we developed and validated the spatially explicit simulation model ModEST, which calculates coupled dynamics of nutrients, water and individual plants characterised by traits. We then simulated all possible combinations of eight plant species with different levels of diversity to assess the role of plant diversity and traits on multifunctionality, the provision of six ecosystem functions (covering three ecosystem services), as well as trade-offs and synergies among the functions under current and future climatic conditions.Our results show that multifunctionality cannot fully be achieved because of trade-offs among functions that are attributable to sets of traits that affect functions differently. Our measure of multifunctionality was increased by higher levels of planted species richness under current, but not future climatic conditions. In contrast, single functions were differently impacted by increased plant diversity. In addition, we found that trade-offs and synergies among functions shifted with climate change.Synthesis and application. Our results imply that restoration ecologists will face a clear challenge to achieve their targets with respect to multifunctionality not only under current conditions, but also in the long-term. However, once ModEST is parameterized and validated for a specific restoration site, managers can assess which target goals can be achieved given the set of available plant species and site-specific conditions. It can also highlight which species combinations can best achieve long-term improved multifunctionality due to their trait diversity.

scholarly journals Sequestering seawater on land: a water-based solution to global issues

F1000Research ◽  
2017 ◽  
Vol 5 ◽  
pp. 889
Author(s):  
Stéphane Boyer ◽  
Marie-Caroline Lefort
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Biodiversity Loss ◽  
Global Scale ◽  
Water Desalination ◽  
Global Issues ◽  
Excess Water ◽  
Desalination Plants ◽  
The Cost

The ‘surplus’ of oceanic water generated by climate change offers an unprecedented opportunity to tackle a number of global issues through a very pragmatic process: shifting the excess water from the oceans onto the land. Here we propose that sea-level rise could be mitigated through the desalination of very large amounts of seawater in an international network of massive desalination plants. To efficiently mitigate sea-level rise, desalinized water could be stored on land in the form of crop, wetlands or new forests. Based on a US$ 500 million price to build an individual mega desalination plant with current technology, the cost of controlling current sea-level rise through water desalination approaches US$ 23 trillion in investment and US$ 4 trillion per year in operating costs. However, the economic, environmental and health benefits would also be immense and could contribute to addressing a number of global issues including sea-level rise, food security, biodiversity loss and climate change. Because these issues are intimately intertwined, responses should aim at addressing them all concurrently and at global scale.

scholarly journals CECILIA Regional Climate Simulations for Future Climate: Analysis of Climate Change Signal

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Michal Belda ◽  
Petr Skalák ◽  
Aleš Farda ◽  
Tomáš Halenka ◽  
Michel Déqué ◽  
...  
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Global Scale ◽  
Climate Change Signal ◽  
Northwestern Part ◽  
Climate Simulations ◽  
Climate Analysis

Regional climate models (RCMs) are important tools used for downscaling climate simulations from global scale models. In project CECILIA, two RCMs were used to provide climate change information for regions of Central and Eastern Europe. Models RegCM and ALADIN-Climate were employed in downscaling global simulations from ECHAM5 and ARPEGE-CLIMAT under IPCC A1B emission scenario in periods 2021–2050 and 2071–2100. Climate change signal present in these simulations is consistent with respective driving data, showing similar large-scale features: warming between 0 and 3°C in the first period and 2 and 5°C in the second period with the least warming in northwestern part of the domain increasing in the southeastern direction and small precipitation changes within range of +1 to −1 mm/day. Regional features are amplified by the RCMs, more so in case of the ALADIN family of models.

scholarly journals A well-timed shift from local to global agreements accelerates climate change mitigation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Vadim A. Karatayev ◽  
Vítor V. Vasconcelos ◽  
Anne-Sophie Lafuite ◽  
Simon A. Levin ◽  
Chris T. Bauch ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Change Mitigation ◽  
Large Scale ◽  
World Wide ◽  
Building Blocks ◽  
Global Scale ◽  
Climate Mitigation ◽  
Limited Efficacy ◽  
Policy Shift ◽  
Change Mitigation

AbstractRecent attempts at cooperating on climate change mitigation highlight the limited efficacy of large-scale negotiations, when commitment to mitigation is costly and initially rare. Deepening existing voluntary mitigation pledges could require more stringent, legally-binding agreements that currently remain untenable at the global scale. Building-blocks approaches promise greater success by localizing agreements to regions or few-nation summits, but risk slowing mitigation adoption globally. Here, we show that a well-timed policy shift from local to global legally-binding agreements can dramatically accelerate mitigation compared to using only local, only global, or both agreement types simultaneously. This highlights the scale-specific roles of mitigation incentives: local agreements promote and sustain mitigation commitments in early-adopting groups, after which global agreements rapidly draw in late-adopting groups. We conclude that focusing negotiations on local legally-binding agreements and, as these become common, a renewed pursuit of stringent, legally-binding world-wide agreements could best overcome many current challenges facing climate mitigation.

scholarly journals Just Societal Transformation: Perspectives of Pastoralists in the Lower Omo Valley in Ethiopia

2021 ◽  
pp. 1-21
Author(s):  
Sabine Troeger
Keyword(s):  
Climate Change ◽  
Decision Making ◽  
Climate Change Adaptation ◽  
Large Scale ◽  
Regional Scale ◽  
Global Scale ◽  
Development Project ◽  
The Face ◽  
Local Actors ◽  
Sugar Development

AbstractPastoralists’ livelihoods in Africa are highly endangered by adverse forces – the climate change being one among those. Against this background, climate change adaptation is conceptualized as strategic agency in the field of risk-laden livelihood environments, that is, agency in the face of risky options and non-calculable uncertainties.The chapter conceptualizes pastoralists’ livelihoods exposed to a four-fold hierarchy of environmental risks and forces defining the actors’ arena of strategic decision making: From the global scale of ever extending impacts by the climate change imperative, to the national scale of government policies in terms of decentralization, challenging people to govern and define their communal efforts in terms of climate change adaptation, and down to the regional scale, which in the presented case is dominated by a large-scale investment, the Kuraz Sugar Development Project, which again confronts local actors with adverse forces toward villagization and eviction from pasture grounds. Right at the end of this hierarchy and in accordance with discourses on “climate services,” the end-users and local actors, the pastoralists, are confronted with and offered a product that they can input into their decision making: cattle feed from the residues of the irrigated sugar cane. The question remains whether substantive aspects of processes turning into true environmental and social justice in terms of recognition, procedures, and distribution will be paid attention to.

scholarly journals Afforestation for climate change mitigation: Potentials, risks and trade-offs, and the role of biophysical climate effects

2020 ◽  
Author(s):  
Jonathan Doelman ◽  
Elke Stehfest ◽  
Detlef van Vuuren ◽  
Andrzej Tabeau ◽  
Andries Hof ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Climate Change Mitigation ◽  
Large Scale ◽  
Mitigation Potential ◽  
Trade Offs ◽  
Effects Of Land Use ◽  
Mitigation Potentials ◽  
Change Mitigation

<p>Afforestation is considered a cost-effective and readily available climate change mitigation option. In recent studies afforestation is presented as a major solution to limit climate change. However, estimates of afforestation potential vary widely. Moreover, the risks in global mitigation policy and the negative trade-offs with food security are often not considered. Here, we present a new approach to assess the economic potential of afforestation with the IMAGE 3.0 integrated assessment model framework (Doelman et al., 2019). In addition, we discuss the role of afforestation in mitigation pathways and the effects of afforestation on the food system under increasingly ambitious climate targets. We show that afforestation has a mitigation potential of 4.9 GtCO<sub>2</sub>/yr at 200 US$/tCO<sub>2</sub> in 2050 leading to large-scale application in an SSP2 scenario aiming for 2°C (410 GtCO<sub>2 </sub>cumulative up to 2100). Afforestation reduces the overall costs of mitigation policy. However, it may lead to lower mitigation ambition and lock-in situations in other sectors. Moreover, it bears risks to implementation and permanence as the negative emissions are increasingly located in regions with high investment risks and weak governance, for example in Sub-Saharan Africa. Our results confirm that afforestation has substantial potential for mitigation. At the same time, we highlight that major risks and trade-offs are involved. Pathways aiming to limit climate change to 2°C or even 1.5°C need to minimize these risks and trade-offs in order to achieve mitigation sustainably.</p><p>The afforestation study published as Doelman et al. (2019) excluded biophysical climate effects of land use and land cover change on climate, even though this is shown to have a substantial effect especially locally (Alkama & Cescatti, 2016). As a follow-up to this study we implement the grid-specific temperature effects as derived by Duveiller et al. (2020) to the mitigation scenarios with large-scale afforestation to assess the effectiveness of afforestation for climate change mitigation as increased or reduced effectiveness may change cost-optimal climate policy. Notably in the boreal regions this can have a major effect, as transitions from agricultural land to forest are shown to have a substantial warming effect due to reduced albedo limiting the mitigation potential in these regions. Conversely, in the tropical areas the already high mitigation potential of afforestation could be even more efficient, as increased evapotranspiration from forests leads to additional cooling. However, it is uncertain whether the high efficiency of afforestation in tropical regions can be utilized as these are also the regions with high risks to implementation and permanence.</p><p> </p><p>References</p><p>Alkama, R., & Cescatti, A. (2016). Biophysical climate impacts of recent changes in global forest cover. Science, 351(6273), 600-604.</p><p>Doelman, J. C., Stehfest, E., van Vuuren, D. P., Tabeau, A., Hof, A. F., Braakhekke, M. C., . . . Lucas, P. L. (2019). Afforestation for climate change mitigation: Potentials, risks and trade-offs. Global Change Biology</p><p>Duveiller, G., Caporaso, L., Abad-Viñas, R., Perugini, L., Grassi, G., Arneth, A., & Cescatti, A. (2020). Local biophysical effects of land use and land cover change: towards an assessment tool for policy makers. Land Use Policy, 91, 104382. </p>

scholarly journals Just Societal Transformation: Perspectives of Pastoralists in the Lower Omo Valley in Ethiopia

2021 ◽  
pp. 1-21
Author(s):  
Sabine Troeger
Keyword(s):  
Climate Change ◽  
Decision Making ◽  
Climate Change Adaptation ◽  
Large Scale ◽  
Regional Scale ◽  
Global Scale ◽  
Development Project ◽  
The Face ◽  
Local Actors ◽  
Sugar Development

AbstractPastoralists’ livelihoods in Africa are highly endangered by adverse forces – the climate change being one among those. Against this background, climate change adaptation is conceptualized as strategic agency in the field of risk-laden livelihood environments, that is, agency in the face of risky options and non-calculable uncertainties.The chapter conceptualizes pastoralists’ livelihoods exposed to a four-fold hierarchy of environmental risks and forces defining the actors’ arena of strategic decision making: From the global scale of ever extending impacts by the climate change imperative, to the national scale of government policies in terms of decentralization, challenging people to govern and define their communal efforts in terms of climate change adaptation, and down to the regional scale, which in the presented case is dominated by a large-scale investment, the Kuraz Sugar Development Project, which again confronts local actors with adverse forces toward villagization and eviction from pasture grounds. Right at the end of this hierarchy and in accordance with discourses on “climate services,” the end-users and local actors, the pastoralists, are confronted with and offered a product that they can input into their decision making: cattle feed from the residues of the irrigated sugar cane. The question remains whether substantive aspects of processes turning into true environmental and social justice in terms of recognition, procedures, and distribution will be paid attention to.

Sign in / Sign up

Export Citation Format

Share Document