Anthropocene最新文献

The Arctic has warmed more than twice the rate of the entire globe. To quantify possible climate change effects, we calculate wind energy potentials from a multi-model ensemble of Arctic-CORDEX. For this, we analyze future changes of wind power density (WPD) using an eleven-member multi-model ensemble. Impacts are estimated for two periods (2020–2049 and 2070–2099) of the 21st century under a high emission scenario (RCP8.5). The multi-model mean reveals an increase of seasonal WPD over the Arctic in the future decades. WPD variability across a range of temporal scales is projected to increase over the Arctic. The signal amplifies by the end of 21st century. Future changes in the frequency of wind speeds at 100 m not useable for wind energy production (wind speeds below 4 m/s or above 25 m/s) has been analyzed. The RCM ensemble simulates a more frequent occurrence of 100 m non-usable wind speeds for the wind-turbines over Scandinavia and selected land areas in Alaska, northern Russia and Canada. In contrast, non-usable wind speeds decrease over large parts of Eastern Siberia and in northern Alaska. Thus, our results indicate increased potential of the Arctic for the development and production of wind energy. Bias corrected and not corrected near-surface wind speed and WPD changes have been compared with each other. It has been found that both show the same sign of future change, but differ in magnitude of these changes. The role of sea-ice retreat and vegetation expansion in the Arctic in future on near-surface wind speed variability has been also assessed. Surface roughness through sea-ice and vegetation changes may significantly impact on WPD variability in the Arctic.

Streams in the southern Piedmont are consistently incised forming deep (∼ 1–3 m) channels within wide valley bottoms. Here, we use a variety of methods to determine the drivers of stream incision in the region. We mapped ∼ 140 historic dams throughout the region since the breaching of mill dams is a known driver of incision elsewhere. We examined stream banks at 20 sites previously dammed and 8 sites with no known dams. At each site, we measured channel depth, described sediments, and dated sedimentary charcoal via radiocarbon dating. We also examined historical aerial photographs and used modern LiDAR to create cross-sections in multiple locations. Our findings indicate that while dams were common throughout the area, they were typically built within the incised streams indicating that incision predates dam construction. Locally, incision appears to have been part of an aggradation-degradation sequence driven by a period of Euroamerican deforestation. Most dams in the region are reported to have been built before 1850 indicating relatively early incision in the region. The legacy sediments overlie Holocene sediments that are similar to those in anastomosing systems that remain in a few stream reaches today. As such, anastomosing systems may have been common in the region during the Holocene. Both legacy sedimentation and erosion appear to continue into the present with alluvial sedimentation, stream straightening, headward erosion, and now a new discharge regime driven by urbanization in the region. Broadly, our results suggest that streams in the southern Piedmont have been consistently impacted by humans since Euroamerican settlement.

Mountain ecosystems provide numerous services vital for the existence of humankind globally. The present study was conducted in the Ladakh region of India to evaluate the socio-cultural values of the ecosystem services provided by the mountainous region. Questionnaires, in-depth interviews, and focus group discussions were used for data collection. It was observed that the respondents identified provisioning and cultural services easily compared to regulating and supporting services. Among services, fresh water and grazing services were valued 5-rating score on a Likert scale of 1–5 by more than 90% of respondents. Likewise, 80% of respondents have a 5-rating score for water retention and regulation, water purification, aesthetic and recreation and ecotourism services. A similar result was observed when the priority of ecosystem services for villagers was discussed through focus group discussions. All respondents viewed freshwater, grazing, and aesthetic services as priority ecosystem services, whereas recreation and ecotourism were prioritised in four villages, water retention and regulation, and water purification in two villages. Using bivariate correlation, the study of interactions among ecosystem services (between services of the same category) demonstrated strong positive to moderate negative correlations. Similarly, the results of the Kruskal-Wallis test indicate that socio-economic factors, including gender, income, and education, have a notable impact (p < 0.05) on most of the services. This suggests that respondents' socio-economic backgrounds influence the values assigned to the services. However, the decline of crucial ecosystem services over the last two decades, as highlighted by participants in the in-depth interviews, raises alarm. Integrating socio-cultural values of ecosystem services while formulating any regional developmental policy could empower the policy-makers to take more informed, eco-friendly actions.

The Earth has lost approximately half of its large mammal species (≥45 kg, one-third of species ≥9 kg) over the past 120,000 years, resulting in depauperate megafauna communities worldwide. Despite substantial interest and debate for over a century, the reasons for these exceptionally high extinction rates and major transformation of the biosphere remain contested. The predominant explanations are climate change, hunting by modern humans (Homo sapiens), or a combination of both. To evaluate the evidence for each hypothesis, statistical models were constructed to test the predictive power of prehistoric human and hominin presence and migration on megafauna extinction severity and on extinction bias toward larger species. Models with anthropic predictors were compared to models that considered late-Quaternary (120–0 kya) climate change and it was found that models including human factors outperformed all purely climatic models. These results thus support an overriding impact of Homo sapiens on megafauna extinctions. Given the disproportionate impact of large-bodied animals on vegetation structure, plant dispersal, nutrient cycling and co-dependent biota, this simplification and downsizing of mammal faunas worldwide represents the first planetary-scale, human-driven transformation of the environment.

Studying the legacies of past human-environment interactions is essential for understanding current landscape and biodiversity patterns. Human influences on past terrestrial and aquatic vegetation are reconstructed based on palynological analysis conducted on a sediment core from Lago di Vedana (Province of Belluno, Northern Italy). This study represents the first pollen record from the Dolomitic lowlands with varying anthropogenic influences throughout the last 700 years. The radiocarbon-dated pollen record begins ca. A.D. 1300 with semi-open forest and moderate human impact, possibly due to activities of the nearby hospice of San Gottardo. Human impact increased with the foundation of the Vedana Charterhouse in the immediate catchment of the lake in A.D. 1457. Activities of the monks involved extensive forest clearing, cultivation of Cannabis/Humulus and possibly hemp retting. In the 19th century the composition of cultivated species changed following the transformation of the Charterhouse into a farm. The 20th century is characterized by expansion of forest taxa and a distinct decline of human influences, probably due to a rural exodus and abandonment of agricultural activities. Vegetation development at Lago di Vedana is consistent with general trends in the Italian Alps and reveals local cultivation practices. The results illustrate the close intertwinement of climatic trends and local human influences, modulated by regional socio-cultural developments during the last millennium.

Understanding the factors underlying bird invasions is crucial for their management. Here, the invasion processes of Mexico by the European Starling (Sturnus vulgaris) and the Eurasian Collared-Dove (Streptopelia decaocto) are analyzed. A 30 × 30 km grid-cell map with the presence/absence of both species was generated using citizen-science data to describe their invasion patterns in time and space from their first records until 2016. Binomial Generalized Linear Models were used to determine the invasion probabilities of both species. Geographic Information was used to determine the climatic variables that better explain their presence (abiotic factors) and the number of phylogenetically closely-related species (biotic factors). A bioclimatic model was used to test if the role that climatic variables play to determine the invasion success of birds at the global scale holds at regional scales. This model related the invasion probabilities of each species with biotic and abiotic factors. The main findings are: (1) Both species have expanded from established populations in the US, and new introductions by bird-trade. (2) European Starlings invaded the country slower than Eurasian Collared-Doves. (3) European Starlings invaded areas with dry and temperate climates, while Eurasian Collared-Doves invaded most of the country, being positively affected by temperature and precipitation. (4) Invasion probabilities of both species were not constrained by phylogenetically closely-related species richness. This study indicates that for exotic invasive birds that exploit agricultural areas, biotic factors do not provide invasion resistance of megadiverse countries such as Mexico.

The land system faces many pressures from the provision of biomass resources and space to the economy. The need to understand land use and cover changes and its drivers is of high importance. This work presents an innovative approach by applying a transdisciplinary approach combining the methods of spatial analysis Land Cover Flows with the methods from the concept of socio-economic metabolism, Material and Energy Flow Accounting, Human Appropriation of Net Primary Production (HANPP) and Final Energy Return on Investment (FEROI). Our main aim is to identify the main land use changes and land cover flows, link them to the underlying socio-economic processes and interpret them in a historical context. Our results show that the overall land use intensity is growing although the positive trends of growing grasslands and forests started after the collapse of communism. The growing intensity of agricultural production with increasing suburbanisation reversed these trends. Until the 2000s the HANPP decreased but at the end of the period increased from 55 % in 2012 to 70 % in 2018. Volumes of the extraction of agricultural biomass are growing while the area of agricultural land has decreased. FEROI grew and stabilised to around 1.0 in the last period (2012–2018) comparable to the value found in the year 2001. The suburbanisation rates peaked after the year 2000 at 250 m²/km²/yr.

The impact from humans on soils, particularly in terms of intensive agriculture, has been most noticeable in the last 200 years. Intensive agricultural activities have caused soil organic carbon (SOC) to decline in many parts of the world. However, there is a dearth of approaches that can spatially estimate the change of SOC due to human influence. Here, we used the concept of Pedogenon to stratify the landscape into soil classes called Pedogenons. Within each Pedogenon, we sampled representative soils under native vegetation and soils under intensive human management. We surveyed the lower Namoi Valley area, NSW, Australia (1700 km²), comprising 13 Pedogenons (soil classes) and analysed SOC on 99 soil cores. Using Digital Soil Mapping techniques, the SOC data were used for mapping SOC every 10 cm down to 1 m using environmental covariates. Sampling points under native vegetation were used to map SOC under the native state, and all data were used for mapping SOC current state. By comparing the SOC maps at two states (native and current), we assessed SOC change. The results show that the SOC loss in irrigated cropping areas was the largest, with surface SOC content decreased by 38%, followed by non-irrigated cropping (30% loss), and pasture (19% loss). All cropping areas show a decrease in SOC stock content at least 5 t C ha⁻¹. SOC loss was greatest in the surface soils and decreased exponentially with depth. We further demonstrate that each Pedogenon can be used to define SOC sequestration potential. Understanding SOC change can provide information on areas under SOC loss threat and require immediate remediation.

Cropland expansion is effected by physiogeographic and sociocultural factors, which vary across region and over time, but have not been adequately represented in large-scale anthropogenic land cover change scenarios. Taking preindustrial cropland expansion in France, Germany, and Italy as a case study, this study first adopted a productivity-based estimation of cropland per capita, which converted crop yield to cropland demand per capita through negative correlations under different crop rotations, to improve the accuracy of national cropland areas. Then, a new allocation algorithm was proposed to allocate national cropland areas into 5′× 5′ grids. The algorithm combines land suitability, which characterizes regional differentiation of potential productivity indicated by physiogeographic factors (climate, topography, soil, etc.) that dominate cultivation, and cultivation preference, which quantifies sociocultural impacts by kernel density estimation based on city information (i.e., location, size, accessibility). The cropland cover scenario here shows similar phases but different modes of cropland expansion in these countries: (1) National cropland areas increased 1.73–2.46 times during the 11th–13th centuries, manifested by the expanding cultivated ranges in France and Germany and the increasing cultivation intensity in Italy. (2) National cropland fractions decreased by 9.16–19.98 percentage points in the 14th century, accompanied by widespread reductions in cultivation intensity. (3) Cropland gradually recovered toward its peak in 1300 AD during the 15th–18th centuries, achieved by general and remarkable increases in cultivation intensity. Compared to representative global datasets, this study is more consistent with cultivation-related descriptions in the literature, especially with respect to the cropland expansion in newly cultivated regions and on marginal lands.

Phosphorus (P) is an essential nutrient, which at excessive concentrations can cause eutrophication of aquatic ecosystems. In freshwater wetlands, water quality deteriorates under these conditions, often succumbing to algal or duckweed dominance, over the biodiversity of other aquatic vegetation. Freshwater sediment may act as an internal source of legacy bound P that can induce production of algal and duckweed blooms beyond what may be expected from external loading of P alone. This study assesses the mobility, bioavailability, and origin of phosphorus in wetland ditch systems at the designated site of special scientific interest, West Sedgemoor. Based upon associations with different P species, using principal component analysis, a clear distinction was observed between sites outside and within the West Sedgemoor Nature Reserve (managed by the Royal Society of the Protection of Birds). Sites outside the nature reserve, typically wet and damp grassland used for arable use and grazing, were generally correlated to higher percentages (median 58.5 %) of non-apatite inorganic P (associated with iron and aluminium minerology) and higher total P levels (average 1277 mg/kg), associated with algal and duckweed blooms, in comparison to areas within the nature reserve (median non-apatite inorganic P; 49.9 %) (average total phosphorus; 936.9 mg/kg).