Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. The plausibility of a planetary-scale ‘tipping point’ highlights the need to improve biological forecasting by detecting early warning signs of critical transitions on global as well as local scales, and by detecting feedbacks that promote such transitions. It is also necessary to address root causes of how humans are forcing biological changes.
All content in this area was uploaded by Mikael Fortelius
Content may be subject to copyright.
A preview of the PDF is not available
... It is estimated that more than 500 species may disappear each year in the short term (Monanstersky, 2014). In the long term, extinction rates will only accelerate if no action is taken (Pereira et al., 2010;Barnosky et al., 2012;Webb & Mindel, 2015;Wagner et al., 2021). ...
The loss of biodiversity is one of the most serious environmental issues in the Anthropocene. Understanding the extinction risk of species is essential for preemptive conservation measures, but is hampered by gaps in geographical and evolutionary knowledge, especially in areas/regions that are highly diverse in species. Combined with a 21 109‐taxon angiosperm mega‐phylogeny and comprehensive species distribution database, we evaluated the characteristics of angiosperm extinction risk at the Sino‐Himalaya and the Tibetan Plateau (SHTP). Overall, our results show that there is a strong interaction between evolutionary and environmental factors on extinction risk, and both contribute spatially to threat processing in the SHTP. The extinction risk of angiosperms in this region is spatially and phylogenetically clustered; the clades with low species richness are significantly more vulnerable to extinction than species‐rich ones; the regions with the highest extinction risk are concentrated in the mountainous areas of southwest China. Integrated with the existing Red List, we further delineated more than 3000 potentially threatened species and proposed practical conservation priorities for four types of species in the SHTP. The extinction risk of angiosperms showed both phylogenetically and spatially aggregate characteristics, serving as an important reference for predicting extinction trends and the formulation of targeted conservation strategies.
... Therefore, identifying the state of ecosystems before such transitions in the ecosystem state is increasingly important (Groffman et al. 2006). However, anticipating and monitoring of a state change in the quality or properties of complex ecosystems, such as wetland ecosystems, are not straightforward (Hastings and Wysham 2010; Barnosky et al. 2012). ...
The resilience of ecosystems, especially wetlands, plays a vital role in maintaining biodiversity, regulating climate, and supporting the livelihoods of communities. However, these ecosystems are increasingly threatened by both human activities and natural disturbances. To effectively manage and conserve these environments, it is imperative to comprehend the dynamics of various proxies that can indicate the state of an ecosystem, which may exhibit linear, non-linear, or abrupt changes over time. Although there has been considerable research focused on the quantitative analysis of wetland ecosystem dynamics prior to a state change—such as the transition from wetland to bare land—there remains a gap in understanding the alterations in water and energy balance dynamics within wetlands. In this study, we investigated the temporal patterns of key components of the energy balance system, including latent heat flux, sensible heat flux, and soil heat flux, alongside water dynamics as primary indicators of wetland change. We quantified water and energy dynamics using data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the National Centers for Environmental Prediction (NCEP). By employing the Brock, Dechert, and Scheinkman (BDS) test along with non-parametric drift-diffusion jump (NDDJ) model approaches, we analyzed the temporal dynamics ofwater and energy dynamics at Kobi Wetland, a site protected under the Ramsar Convention. KobiWetland has experienced significant reductions in water levels, largely attributed to drought conditions and unsustainable agricultural practices in the area. The findings revealed a significant increase in non-linear dynamics in both water area and energy dynamics over the study time period. The BDS test and NDDJ analysis showed that sensible heat flux showed the strongest trend (Kendall’s τ = 0.48), with significant nonlinearity, compared with other indicators that can signal a loss of resilience and abrupt change. In contrast, the water area indicator (i.e., Modified Normalized Difference Water Index) has a weak trend (τ = 0.14) with minimal nonlinearity, while latent and soil heat flux exhibit moderate trends (Kendall’s τ = 0.34 and 0.38) and nonlinearity. This research contributes to the drought monitoring and predicting of water and energy dynamics changes in wetland ecosystems that can serve as signals of resilience loss.
Climate change has become a matter of security in recent policy discussions. The scale of the transformations we are living through is slowly dawning on policy makers but the implications for both security and policy making in general of our new geological conditions, our living in the new geological epoch of the Anthropocene, have yet to be thought through carefully. The basic geopolitical premises in security thinking are now in need of a radical overhaul in light of the insights from earth system science. Simplistic assumptions of environmental change leading directly to conflict are misleading at best and dangerous at worst. Climate security discussions now have to engage directly with global environmental change and with earth systems science in particular. Climate security in the long run is not a matter of environmental change causing political difficulties, but rather a matter of contemporary political difficulties causing accelerating climate change. Climate change is a production problem, not one that can be managed in the terms of traditional environmental thinking; security thinking needs to focus on the implications of this rethinking of traditional geopolitical assumptions.
Anthropogenic climate change is projected to become a major driver of biodiversity loss, destabilizing the ecosystems on which human society depends. As the planet rapidly warms, the disruption of ecological interactions among populations, species and their environment, will likely drive positive feedback loops, accelerating the pace and magnitude of biodiversity losses. We propose that, even without invoking such amplifying feedback, biodiversity loss should increase nonlinearly with warming because of the non-uniform distribution of biodiversity. Whether these non-uniformities are the uneven distribution of populations across a species’ thermal niche, or the uneven distribution of thermal niche limits among species within an ecological community, we show that in both cases, the resulting clustering in population warming tolerances drives nonlinear increases in the risk to biodiversity. We discuss how fundamental constraints on species’ physiologies and geographical distributions give rise to clustered warming tolerances, and how population responses to changing climates could variously temper, delay or intensify nonlinear dynamics. We argue that nonlinear increases in risks to biodiversity should be the null expectation under warming, and highlight the empirical research needed to understand the causes, commonness and consequences of clustered warming tolerances to better predict where, when and why nonlinear biodiversity losses will occur.
This article is part of the discussion meeting issue ‘Bending the curve towards nature recovery: building on Georgina Mace’s legacy for a biodiverse future’.
A emergência, a complexidade multiescalar e o propósito das questões ambientais exigem um olhar diferente sobre as práticas sociais que impactam na Natureza e no Ambiente. Nessa lógica evocamos a praxiografia de Annemarie Mol, procurando estudar as questões ambientais sem as isolar dos contextos das práticas sociais a elas anexadas. Além desta perspetiva, adicionamos o método assemblage de John Law, para tornar visível um conjunto de ressonâncias na organização social e ecológica, reconhecendo, também, a diversidade epistemológica e ontológica do mundo. O texto apresenta uma abordagem fractal, centrando a sua reflexão entre as práticas que criam diferentes perspetivas e o advento de práticas que geram diferentes realidades, mais em harmonia com o Ambiente e a Natureza, contribuindo para repensar e agir sobre os problemas socioambientais.
Conservation biologists recognize a duty to maintain as much value as possible in ecosystems that are threatened by recent anthropogenic impacts. Until recently the paradigm of contemporary conservation seemed relatively straightforward: the best way to maintain the value of species and ecosystems at a given location was to maintain—or shepherd the system back towards—historical conditions. Among the most difficult theoretical tasks was the determination of “baseline” historical conditions (or trajectories) to return to, recognizing the dynamism of ecosystems over time. However, the rate, scale, and magnitude of contemporary climate change, species introductions, and land-use change make it increasingly impractical to return locations to any kind of historical state. This forces a paradigm shift which is both ongoing and difficult, and necessitates a rigorous evaluation of the scientific and ethical foundations of modern conservation along with a careful reexamination of terminology. Here, I discuss the moral relevance and waning utility of the geographically-based and dichotomous understanding of “native” (or “in situ”) which is an important component of conservation ethics and practice. I then propose a new understanding of nativeness in which a species is native—not to a geographic location—but to a quantifiable set of biotic, climatic, geologic, and topographic conditions (i.e. its niche) that can then map to geographic space. Following this, I demonstrate the unique utility of this concept, which I will refer to as “econativeness,” in thinking through conservation problems—range expansions, range contractions, species introductions, and assisted migration—where the classical understanding of nativeness has become increasingly inadequate for assessing the moral value of species.
The possibility of abrupt transitions threatens to poise ecosystems into irreversibly degraded states. Synthetic biology has recently been proposed to prevent them from crossing tipping points. However, there is little understanding of the impact of such intervention on the resident communities. Can such modification have ‘unintended consequences’, such as loss of species? Here, we address this problem by using a mathematical model that allows us to simulate this intervention scenario explicitly. We show how the indirect effect of damping the decay of shared resources results in biodiversity increase, and last but not least, the successful incorporation of the synthetic within the ecological network and very small-positive changes in the population size of the resident community. Furthermore, extensions and implications for future restoration and terraformation strategies are discussed.
Complex spatio-temporal systems like lakes, forests and climate systems exhibit alternative stable states. In such systems, as the threshold value of the driver is crossed, the system may experience a sudden (discontinuous) transition or smooth (continuous) transition to an undesired steady state. Theories predict that changes in the structure of the underlying spatial patterns precede such transitions. While there has been a large body of research on identifying early warning signals of critical transitions, the problem of forecasting the type of transitions (sudden versus smooth) remains an open challenge. We address this gap by developing an advanced machine learning (ML) toolkit that serves as an early warning indicator of spatio-temporal critical transitions, Spatial Early Warning Signal Network (S-EWSNet). ML models typically resemble a black box and do not allow envisioning what the model learns in discerning the labels. Here, instead of naively relying upon the deep learning model, we let the deep neural network learn the latent features characteristic of transitions via an optimal sampling strategy (OSS) of spatial patterns. The S-EWSNet is trained on data from a stochastic cellular automata model deploying the OSS, providing an early warning indicator of transitions while detecting its type in simulated and empirical samples.
The Last Glacial-Interglacial Transition is one of the most intensively studied periods in Earth History. The rapid climate and environmental changes that occurred during the transition can be used to test ideas about the functioning of our climate system. The stratigraphy of this period has been thoroughly investigated and, in particular, the recently proposed event stratigraphy for the Last Glacial-Interglacial Transition based on the Greenland ice core records serves as a tool for synchronisation of records from the ice, marine and terrestrial environment. The causes behind the rapid climate changes are most likely to have been changes in ocean circulation, partly triggered by ice-melting during deglaciation. While the picture for the North Atlantic region is becoming more and more clear, complex patterns of change over the globe remain to be studied. The functioning of the complex feed-back mechanisms requires an interdisciplinary approach between geoscientists from different disciplines.
Human alteration of Earth is substantial and growing. Between one-third and one-half of the land surface has been transformed
by human action; the carbon dioxide concentration in the atmosphere has increased by nearly 30 percent since the beginning
of the Industrial Revolution; more atmospheric nitrogen is fixed by humanity than by all natural terrestrial sources combined;
more than half of all accessible surface fresh water is put to use by humanity; and about one-quarter of the bird species
on Earth have been driven to extinction. By these and other standards, it is clear that we live on a human-dominated planet.
Earths resources are consumed by one of its 5-30 million species homo sapiens or man at a rate disproportionately greater than any other species. Mans impact on the biosphere is measured in terms of net primary production (NPP). NPP is the amount of energy remaining after the respiration of primary producers (mostly plants) is subtracted from the total amount of biologically fixed energy (mostly solar). Human output is determined by 1) the direct NPP used for food fuel fiber or timber which yields a low estimate 2) all NPP of cropland devoted to human activity and 3) both 1) and 2) and land conversion for cities or pastures as well as conversion which results in desertification and overuse of lands. This last output determination yields a high estimate. Calculations are made for global NPP and each of the 3 estimates of low intermediate and high human output. Data are based on estimates by Ajtay et al. Armentano and Loucks and Houghton et al. and on the Food and Agriculture Organizations (FAO) summaries. Petagram (Pg) is used to calculate organic matter; this is equivalent to 10 to the 15th power grams or 10 to the 9th power metric tons. Carbon has been converted to organic matter by multiplying by 2.2. Matter in kilocalories has been converted to organic matter by dividing by 5. Intermediate or conservative estimates have been included. The standard of biomass is 1244 Pg and an annual NPP to 132.1. The NPP of marine and freshwater ecosystems is considered to be 92.4 Pg which is a low estimate. The low calculation of human (5 billion persons) consumption of plants at a caloric intake of 2500 kilocalories/person/day is .91 Pg of organic matter which equals .76 Pg of vegetable matter. The global production of human food is 1/7 Pg for grains and for human and livestock fed or .85 Pg of dry grain material and .3 Pg in nongrain dry material with dry grain material and .3 Pg in nongrain dry material with a subtraction of 20% for water content. 34% or .39 Pg is lost to waste and spoilage. Consumption by livestock forest usage and aquatic ecosystems is computed. The overall estimate for human use if 7.2 Pg of organic matter/year or 3% of total NPP/year. The intermediate figures take into account cropland pastureland forest use and conversion; the overall estimate of human use is 42.6 Pg of NPP/year of 19.0% (42.6/224.5) of NPP (30.7% on land and 2.2% on seas). The high estimate yields human use of 58.1 Pg/year on land or 40% (58.1/149.6) of potential land productivity or 25% (60.1/149.8 + 92.4) of land and water NPP. The remaining 60% of land is also affected by humans. The figures reflect the current patterns of exploitation distribution and consumption of a much larger population. These patterns amount to using >50% of NPP of land; there must be limits to growth.
1 To whom correspondence should be addressed. E-mail: {at}uwyo.edu; For Ecol Man 254:390–406. CrossRef. ↵: Lawler ,; et al. ,; Huettman F,; Moritz C,; Peterson AT. (2004) New developments in museum-based informatics and applications in biodiversity analysis.
Human‐induced carbon and nitrogen fertilization are generating a strong imbalance with P. This imbalance confers an increasingly important role to P availability and N : P ratio in the Earth's life system, affecting carbon sequestration potential and the structure, function and evolution of the Earth's ecosystems.
