Anthropocene最新文献

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analysis was conducted on modern and archaeological polar bear bone collagen from the Canadian Arctic Archipelago to investigate potential changes in polar bear foraging ecology over four-millennia. Polar bear δ¹³C values showed a significant decline in the modern samples relative to all archaeological time-bins, indicating a disruption in the sources of production that support the food web, occurring after the Industrial Revolution. The trophic structure, indicated through δ¹⁵N, remained unaltered throughout all time periods. The lower δ¹³C observed in the modern samples indicates a change in the relative importance of pelagic (supported by open-water phytoplankton) over sympagic (supported by sea ice-associated algae) primary production. The consistency in polar bear δ¹³C through the late Holocene includes climatic shifts such as the Medieval Warm Period (MWP, A.D. 950–1250) and the early stages of the Little Ice Age (LIA, A.D. 1300–1850). These findings suggest that polar bears inhabit a food web that is more pelagic and less sympagic today than it was through the Late Holocene. We suggest that modern, anthropogenic warming has already affected food web structure in the Canadian Arctic Archipelago when modern data are contextualized with a deep time perspective.

Transformative rather than incremental adaptation will be necessary to keep pace with rapidly changing social-ecological systems characteristic of the Anthropocene. Alongside mounting urgency for transformative adaptation, there is also growing recognition that it is no longer possible to achieve sustainable transformation without also addressing security and equity concerns. Thus, dimensions of security, equity, and sustainability (SES) are increasingly intersected in transformation research and practice. However, interpretations of SES dimensions and their intersections vary widely across disciplines, policy sectors, and problem domains, and knowledge of SES intersections is fragmented. To navigate this vast body of knowledge, a conceptual framework is presented that: 1) integrates a set of guiding critical questions for defining and assessing different framings for each SES dimension; 2) identifies modes of theorizing SES intersections; and 3) relates the previous two elements to leverage points targeted, either theoretically or in practice, for transformative change. Nine prominent integrated concepts and associated case studies were identified that explicitly addressed intersections among all SES dimensions. Integrated concepts addressed a diversity of leverage points, but only two mixed epistemological and methodological approaches sufficiently to provide explanatory insight into SES intersections while also supporting science-based change-making. Potential risks of ambiguity around SES framings and needs for addressing SES intersections in future transformation research are highlighted. Optimistically, transformation scholarship has moved beyond simply stating the importance of SES dimensions to focusing on the causal interactions among SES dimensions, which is leading to compelling new blends of explanatory and action-oriented paradigms to pursue transformation.

Water footprint accounting can evaluate the real occupancy of water resources by combining the consumption of blue water and green water. In this study, we calculated agricultural water footprint (AWF) including six patterns of crops water footprint (CWF) and three patterns of animal products water footprint (APWF) from 2000 to 2020 in Gansu Province, China, then the spatiotemporal matching pattern and its heterogeneity of AWF and socioeconomic factors were identified at the ecological functional zone level. The results show that: (1) The AWF showed a rising trend, increasing by 40%. (2) The spatial difference of AWF was obvious, the main contributor to the CWF changed from wheat to maize, and the main contributors to the APWF were always pork and beef. At the ecological zones level, the central and eastern Loess Plateau and Hexi inland areas together accounted for 60% of the total AWF of Gansu Province. (3) The center of gravity of AWF was always located in Lanzhou, the provincial capital, but tended to gradually move to the northwest. (4) The spatiotemporal matching degree between AWF and population and GDP was relatively good, but it was highly unbalanced between blue water footprint (BWF) and planting area. Considering both water-saving potential and feasibility, we suggest that Gansu Province should carry out sustainable agricultural management from three aspects, that is, optimizing the planting structure, emphasizing water conservation in animal husbandry, and improving the spatial matching degree between AWF and socioeconomic factors.

Coral reefs are extremely productive ecosystems, but widespread changes to benthic community structure resulting from anthropogenic impacts are likely to impact the transfer of organic matter between trophic levels, altering trophodynamics and functional diversity. We used stable isotope analysis to investigate differences in resource availability, niche width and trophic diversity of seven coral reef fish species representing key functional feeding groups on a sponge-dominated reef and an adjacent, coral-dominated reef. Four out of seven fish species had wider isotopic niches at the sponge-dominated reef compared to the coral-dominated reef, including the obligate corallivore. The proximity of the isotopic niche of the obligate corallivore to the isotopic niche of the detritivore suggests that the obligate corallivore supplemented its diet with detritus at the sponge-dominated reef. Fish sampled at the sponge-dominated reef had a significantly lower mean trophic position, used a lower range of resources (based on δ¹³C range) and obtained more carbon from benthic production than at the coral-dominated reef. Trophic diversity was lower and functional redundancy higher at the sponge-dominated reef, suggesting that fish on the sponge reef had more similar diets to each other than at the coral-dominated site. Observed differences in trophic structure between the two sites are likely due to fewer organic matter pathways supporting secondary production at the sponge-dominated reef, suggesting that transitions sponge-dominated systems will reduce community stability by eroding the potential for niche partitioning and species co-existence.

Worldwide, rivers are extensively fragmented by anthropogenic structures, reducing longitudinal connectivity, inhibiting migration and leading to severe declines in many fish populations, especially for diadromous species. However, few studies have determined the effects of annual differences in hydrology on catchment penetration past barriers to spawning habitats. We investigated the upstream spawning migration of 120 (n = 61 & 59) acoustic tagged river lamprey (Lampetra fluviatilis) across two contrasting (dry and wet) years in the River Yorkshire Ouse, England. Overall, significantly more lamprey reached spawning habitat (76% vs 39%) and penetrated significantly further upstream (median [km] from release, 53.9 vs 16.8) in the wet year than the dry year. Passage at weirs was almost exclusively during elevated river levels, which directly and collectively influenced catchment-wide distribution, especially in the dry year. Indeed, higher proportions entered two upper tributaries in the wet year (9.8% vs 27.1% and 9.8% vs 30.5%), due to increased passage efficiencies at the two main river weirs (60.5–87.5% and 54.5–83.8%), and reached assumed spawning locations 66.5% and 10.9% quicker. By contrast, there was no difference in numbers of lamprey entering, or time taken to arrive at assumed spawning location, in the two lower river tributaries between years. Our study supports the landscape-scale paradigm for ecosystem restoration because of the observed catchment-level effects of hydrology and barrier distribution on fish migration. Connectivity restoration for migratory fish should be implemented at a catchment scale, with planning incorporating spatial information regarding accessibility to key habitats to reap the largest gains.

Crop response characteristics to different timescales of precipitation deficit may represent crop system resilience to drought characteristics. In this study, we assess the crop yield response of major crops to meteorological drought estimated by a standardized precipitation index with multiple timescales (1–12 months) during 1981–2016 all over the globe. We estimate that about one- to two-thirds of global harvested areas of maize, rice, soybean, and wheat, were significantly affected by various drought timescales. Soybean and wheat might respond to more prolonged droughts, while rice and maize responded to short-medium drought time scales. Using multiple machine learning models, we reveal that set of determinants could explain most variations of crop response to drought timescale with average accuracies between 45.7% and 56.0% (across models and crop types). Moreover, this study suggests that crops in warmer and higher water availability (precipitation minus potential evapotranspiration) might respond significantly to more short-term drought. The other factors (i.e., socioeconomic, fertilizer, soil, topography, production, irrigation) shows a complex and weaker effect on defining crop vulnerability to the various drought characteristics. This study attempts to fill the gaps in understanding global crop resistance to different drought characteristics. The future challenge in understanding the multifaceted effect of physical and socioeconomic factors on global crop vulnerability to drought may remain and should be addressed in further studies.

Early farmers used at least two types of agrarian amendments that could raise pH and base saturation levels to allow the cultivation of cereals: marling and plant ash. Ash can be input in many different ways: felling and burning in place, transferring plant material from wastelands and spreading the ash, charring sod or peat blocks, burning stubble after harvest. Marling includes all the practices of amending limestone, from marl to chalky limestone composed of 99% CaCO₃. In order to understand the evolution of these agricultural practices, it is important to identify which of the two techniques was used to amend cereal crops in the past. In order to test the potential of δ^44/40Ca-δ^88/86Sr-⁸⁷Sr/⁸⁶Sr multiple isotope approach for archaeological samples, we first applied the technique to currently grown crops, amended either with marl or with ash from freshly-cut and burned trees. We found that this approach makes it possible to discriminate cereal grains amended either by marling (less radiogenic Sr) or with tree ash (more radiogenic Sr). We also identified a positive correlation between stable Ca and Sr isotope values, suggesting that the Ca and Sr came from similar sources and had undergone similar mass-dependent isotopic fractionation mechanisms. Consequently, we later on mainly focused on stable and radiogenic Sr isotopes. Stable Sr isotope fractionation was also observed between different locations, different organs of a given cereal species and between different cereal types, but also within the same cereal species or the number of grains studied for a given locality, pointing to biological fractionation combined with source variation.

Legacy pollution research has established that over the past 3000 years, mining and metallurgical activities have resulted in widespread deposition of lead (Pb) pollution. However, there is still a limited understanding of how humans have impacted the long-term cycling of Pb in the environment. We present a 4,000-year lake sediment Pb isotope record from Laguna Roya, northwestern Iberia, that identifies and quantifies the predominant sources of atmospheric Pb pollution. For the first time, Pb isotopic compositions of ancient slag samples dated (∼600 BCE–200 CE) from a mining district in the southwest of the Iberian Peninsula are compared to Pb isotope ratios of Pb pollution deposited contemporaneously in lake sediments. In addition, literature Pb isotope ratios of ores from mining regions throughout Iberia are compared with those of leaded gasoline and coal to identify additional sources of anthropogenic Pb. Deposition of atmospheric Pb pollution begins after 950 BCE, and until 1750 CE, the Pb isotopic composition most resembles the southwestern slag deposits, containing a mixture of Pb ores from southeast Iberia (up to 36%) and southwest Iberia (∼74%). Between 1750 and 1960 CE, Pb pollution is attributed to Pb mining in southcentral Iberia. After 1960 CE, the dominant Pb pollution source (∼85%) is again metal refining in southwestern Iberia, and only ∼15% is from leaded gasoline. Provenance and reconstruction of the temporal and spatial distribution of legacy Pb pollution further our understanding of how humans have affected the biogeochemical cycle of this toxic element in the environment over time.

This paper investigates the locations of past watermills in terms of their hydrological and geomorphological conditions. In our analysis, the natural landscape was treated as a resource of factors favouring or hindering the location of a specific mill and the possibility of their persistence as technological and economic conditions became increasingly unfavourable throughout history. An answer was provided to the question of which areas were environmentally preferable for the location of a plant using the energy of flowing water and in which types of landscape - enclaves of the cultural mill landscape were preserved for the longest time. The Maximum Entropy Method (MaxEnt) was used to determine the spatial probability distribution of the mill reservoir locations based on the delimitation of natural landscape types. Ten per cent of the study area shows a high occurrence probability for mill location (>0.9). The spatial distribution of MaxEnt outcomes shows that landscapes prone to mill location mainly concentrate on the edge of morainic plateaus and in the tunnel valleys. The research results allow us to understand the evolution of the cultural landscape in the lowland area, especially the role of mill settlements in colonising of forest areas and river valleys.

The original meaning of the Critical Zone (CZ) was spatial and pointed to one physical referent: the terrestrial surface of the entire Earth. As usage increased among researchers in the geosciences, social sciences, and humanities, new meanings led to the concept pointing to different places and ideas. Emerging trends have expanded the CZ further: CZs are mapped in computational spacetime and on distant planets and asteroids. The polysemous character of the CZ can be confounding for a field-based science, but Earth scientists and technologists have collaborated to collect and harmonize Big Data sets into a sizable library of CZ research in a short time (around 20 years). In this review, we map the semantic range of the CZ and explore how CZ science has remained coherent even as researchers diversified the concept by developing distinguishable but loosely overlapping meanings. We organize extant meanings into three tiers: (1) Earth’s spatial interface of the geochemical and biological; (2) scientific knowledge of geophysical functionality of the CZ, as represented in an ever-growing library of data or by a single feature as proxy (e.g. soil); (3) a planetary home vulnerable to human disruption. In a time of immense human influence on the CZ, we underscore the latent meaning of planetary home, which marshals motivations of care and protection. These three tiers—the ontological, epistemic, and anthropocenic—build on each other to make the CZ a uniquely valuable concept for navigating the socio-ecological challenges of the Anthropocene.