The Eurasian steppe is the largest steppe region in the world and is an important part of the global grassland ecosystem. The eastern Eurasian steppe has favorable hydrothermal conditions and has the ...highest productivity and the richest biodiversity. Located in the arid and semi-arid region, the eastern Eurasian steppe has experienced large-scale grassland degradation due to dramatic climate change and intensive human activities during the past 20 years. Hence, accurate estimation of aboveground biomass (AGB, gC m−2) and belowground biomass (BGB, gC m−2) is necessary. In this study, plenty of AGB and BGB in-situ measurements were collected among dominated grassland types during summer in 2013 and 2016–2018 in the eastern Eurasian steppe. Vegetation indices from the Moderate Resolution Imaging Spectroradiometer (MODIS), Digital Elevation Model (DEM) and climate variables were chosen as independent variables to establish predictive models for AGB and BGB with random forest (RF). Both AGB (R2 = 0.47, MAE = 21.06 gC m−2, and RMSE = 27.52 gC m−2) and BGB (R2 = 0.44, MAE = 173.02 gC m−2, and RMSE = 244.20 gC m−2) models showed acceptable accuracy. Then the RF models were applied to generate spatially explicit AGB and BGB estimates for the study area over the last two decades (2000–2018). Both AGB and BGB showed higher values in the Greater Khingan Mountains and decreased gradually to the east and west sides. The mean values for AGB and BGB were 62.16 gC m−2 and 531.35 gC m−2, respectively. The climatic factors were much more important in controlling biomass than anthropogenic drivers, and shortage of water and raising temperature were the main limiting factor of AGB and BGB, respectively, in the peak growth season. These findings provide scientific data for the scientific management of animal husbandry and can contribute to the sustainable development of grassland ecology in the eastern Eurasian steppe.
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•Remote sensing provides an effective method for estimating the regional grassland belowground biomass.•Shortage of water and raising temperature limit the aboveground biomass and belowground biomass, respectively.•The climatic factors were much more important than anthropogenic drivers in the eastern Eurasian steppe.
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In this first worldwide synthesis of in situ and satellite‐derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade−1) between 1985 and 2009. ...Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice‐covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade−1) to ice‐free lakes experiencing increases in air temperature and solar radiation (0.53°C decade−1). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.
Key Points
Lake surface waters are warming rapidly but are spatially heterogeneous
Ice‐covered lakes are typically warming at rates greater than air temperatures
Both geomorphic and climate factors influence lake warming rates
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In 1990-1994, over nine survey periods, we recorded a total of 684 breeding attempts deriving from 51 species in a landbird community in arid north-western New South Wales. We investigated whether ...breeding effort was related to regular seasonal patterns (spring vs winter) or to irregular fluctuations in rainfall (pre-drought vs drought vs isolated thunderstorm vs above-average rainfall post-drought). The total breeding effort and number of species breeding in the study area were not correlated with the numbers of individuals or species present at a given time. The overall breeding effort was influenced primarily by season but was modified by rainfall. Spring breeding predominated but the timing and magnitude of the breeding efforts of different movement groups (residents, nomads and migrants) and dietary groups varied. Within these groups, there were inconsistencies between individual species. Residents bred mainly in spring but only in low numbers during the drought. Some resident species with relatively stable food supplies also bred, though to a lesser extent, in winter. Residents did not respond to the breaking of the drought with prolonged or aseasonal breeding. The breeding of nomads appeared to follow rainfall more closely. The greatest nesting effort by nomads occurred in the spring after the drought broke, possibly because of a peak in the availability of foods suitable for the nomads at this time. The uncertainty and extremes of the arid-zone environment are now being exacerbated by ongoing anthropogenic climate change, which is likely to severely impact the breeding efforts of arid-zone birds.
The roosting and breeding behaviour of a pair of Tawny Frogmouths Podargus strigoides was observed on the central Queensland coast over a period of 4 years (2018-2021). The study was conducted in a ...subtropical climate near Rockhampton, and provides data from a different geographical and climatic area compared with previous studies that were conducted in temperate southern Australia (New England Tablelands, Moree, and Sydney, New South Wales, and the Australian Capital Territory). Breeding data matched other studies: breeding in November-December, incubation of 28-30 days, fledging at 27-31 days, care of fledglings from 1-3 months, nests located in a horizontal fork of a tree on the edge of a clearing. Breeding success was high at 80% (8 of 10 nestlings survived). Roost sites were generally in tree species with a fibrous dark bark that provided camouflage, and were mostly within the leafy canopy (average height 9.11 m above ground), which provided protection from high daytime temperatures in both winter and summer. Only early in the morning on very cool days in winter did Frogmouths seek lower perches where sun exposure was greatest. These findings are consistent with other studies identifying thermoregulation and camouflage as important determinants of roost selection, although the need for greater sun exposure in winter was much lower in this study, reflecting the generally warm winter days. Fidelity to roost trees was high (90% of roosts were in four trees) and Frogmouths nested in a different tree each year. Both roosts and nests were confined to a home range of 1.6 ha. The frequency of feeding increased with nestling age, and was higher during the early part of the night. Overall, these findings advance understanding of the breeding biology of the Tawny Frogmouth in subtropical Australia.
The Beijing-Tianjin-Hebei (BTH) region of China is a typical area where both population and economy have been increasing rapidly in recent decades. The rapid economic development and population ...increase also bring severe environmental stresses. To better understand the factors that contribute to the regional ecological environment change, this study aims to disaggregate the effects of climate and human activity on vegetation dynamics based on a vegetation index derived from remote sensing for the BTH region through time. First, we implemented a linear regression analysis on the Enhanced Vegetation Index (EVI) in the BTH region from 2001 to 2015. We found vegetation greening mainly occurred in the mountainous area in the north and the west of the BTH region, where the forests and grasslands dominate, and the vegetation browning was mainly distributed in the southeast, where the built-up lands and croplands were located. Then, we used the Random Forest (RF) regression model to rank the importance of the climatic and anthropogenic factors. The results showed that temperature was the most influential factor among our climate variables while land cover dominated the anthropogenic variables. Finally, this study applied the RF model to disaggregate the climatic effects from that of the anthropogenic effects on vegetation dynamics by keeping human-activity- or climate-related variables constant. It showed that the method was capable of quantifying climatic and anthropogenic effects on vegetation changes. This study also found that the N deposition significantly negatively correlated with the vegetation growth trend in BTH. The approach this study proposed advanced our understanding of the driving factors of vegetation dynamics, and the approach is applicable elsewhere.
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•Climatic and anthropogenic influences on vegetation dynamics were disaggregated.•Temperature is the most influential natural factor affecting vegetation change in the BTH region.•Land cover change is the dominant anthropogenic factor causing vegetation change in the BTH region.•N deposition negatively correlates with vegetation growth trending.
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This book delivers a realistic and feasible framework for creating resilient landscapes in an era of anthropogenic climate change.From across six continents, this book presents fifteen case studies ...of differing sociocultural, economic, and biophysical backgrounds that showcase opportunities and limitations for creating resilient landscapes throughout the world. The potential to create socio-ecological resilience is examined across a wide range of landscapes, including agricultural, island, forest, coastal, and urban landscapes, across sixteen countries: Argentina, Australia, Brazil, Denmark, Finland, Greece, Guatemala, Japan, Mexico, Norway, Samoa, South Africa, the United States, Turkey, Uruguay, and Vanuatu. Chapters discuss current and future issues around creating a sustainable food system, conserving biodiversity, and climate change adaptation and resilience, with green infrastructure, nature-based architecture, green-tech, and ecosystem services as just a few of the approaches discussed. The book emphasizes solution-oriented approaches for an "ecological hope" that can support landscape resiliency in this chaotic era, and the chapters consider the importance of envisioning an unpredictable future with numerous uncertainties. In this context, the key focus is on how we all can tackle the intertwined impacts of climate change, biodiversity loss, and large-scale land-cover conversion in urban and non-urban landscapes, with particular attention to the concept of landscape resiliency. The volume provides that much-needed link between theory and practice to deliver forward-thinking, practical solutions.This book will be of great interest to students, researchers, practitioners and policymakers who are interested in the complex relationship between landscapes, climate change, biodiversity loss, and land-based conversion at local, national and global scales.
The present study aimed to evaluate the influence of environmental factors on essential oils (EOs) composition of Origanum compactum populations sampled all over the distribution area of the species ...in Morocco, and to determine the extent of the chemical profiles throughout the geographical distribution of the species. The chemical compositions were submitted to canonical correlation analysis and canonical discriminant analysis that indicated a significant relationship between oil components and some environmental factors. According to their chemical composition and edapho‐climatic characteristics, two major groups of populations were differentiated. The first group was composed of samples growing in regions with humid climate, clayey, sandy, and alkaline soils. These samples showed high thymol, α‐terpineol, linalool, and carvacryl methyl oxide content. The second group consisted of plants belonging to semi‐arid climate, and growing at high altitudes and silty soils. These samples were characterized by high carvacrol, α‐thujene, α‐terpinene, and myrcene content. However, populations exposed to sub‐humid climate, appeared less homogeneous and belong mainly either to the first or second group. A significant correlation between some edaphic factors (pH, K2O content, soil texture) and the EOs yield of O. compactum plants was evidenced. In spite of the correlation obtained for the oil composition with edapho‐climatic factors and the variance explained by the environmental data set, the observed EO diversity might be also genetically determined.
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A top priority in climate research is obtaining broad-extent and long-term data to support analyses of historical patterns and trends, and for model development and evaluation. Along with directly ...measured climate data from the present and recent past, it is important to obtain estimates of long past climate variations spanning multiple centuries and millennia. Dendroclimatic Studies at the North American Tree Line presents an overview of the current state of dendroclimatology, its contributions over the past few decades, and its future potential. The material included is not useful not only to those who generate tree-ring records of past climate- dendroclimatologists, but also to users of their results-climatologists, hydrologists, ecologists and archeologists. In summary, this book: * Sheds light on recent and future climate trends by assessing long term past climatic variations from tree rings * Is a timely coverage of a crucial topic in climate science portraying recent warming trends which are of serious concern today * Features well-reputed scientists highlighting new advanced methodologies to reconstruct past climate change * Models the tree growth environmental response
•Thinning greatly affected the soil physicochemical properties.•Soil and stump respiration were promoted in 1 and 3 years after thinning.•The responses of respirations to environmental conditions ...changed after thinning.•Stump respiration played an important role in carbon release in long term.
Thinning is an important forest management practice that can greatly affect ecosystem carbon budgets. However, few studies have reported the instant and prolonged effects of thinning under the same climate conditions, which is the scientific issue addressed by this study. The effects of thinning on soil physicochemical properties, soil respiration (RSoil), stump respiration (RStump) and carbon (C) release were quantified in a subtropical plantation based on parallel observations in Unthinned, 1-year post-thinning (PT1-yr) and 3-year post-thinning (PT3-yrs) treatments. Generally, the pH and NO3–-N decreased, and the NH4+-N and soil water contents (SWC) increased in PT1-yr and PT3-yrs. Soil temperature (T) decreased in PT1-yr and increased in PT3-yrs. Thinning promoted RSoil, but a slowdown of the promoting effects was found in PT3-yrs. Thinning continuously promoted RStump significantly; therefore, RStump in PT3-yrs > PT1-yr > Unthinned. The responses of RSoil and RStump to T and SWC changed after thinning. Among Unthinned, PT1-yr and PT3-yrs, the fitting surfaces for modeling the relations between RSoil and TSoil, SWCSoil became flatter. In contrast, the fitting surfaces become more curved for RStump and TStump, SWCStump. These results could be attributed to the complicated changes in the composition of respiration and the changing soil environment. The C release from the underlying surface increased year by year during the three years after thinning. The C released through RSoil was the dominant component. However, the C released through RStump determined the significant difference between C release in PT1-yr and PT3-yrs, which indicated the potential importance of RStump over time after thinning. As thinning is an important way to optimize the carbon sink function of global forests, extensive and intensive studies on thinning effects and the underlying mechanisms are necessary, which would be beneficial for an accurate estimation of forest carbon budgets under future climate change.
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The world’s coral reefs are being degraded, and the need to reduce local pressures to offset the effects of increasing global pressures is now widely recognized. This study investigates the spatial ...and temporal dynamics of coral cover, identifies the main drivers of coral mortality, and quantifies the rates of potential recovery of the Great Barrier Reef. Based on the world’s most extensive time series data on reef condition (2,258 surveys of 214 reefs over 1985–2012), we show a major decline in coral cover from 28.0% to 13.8% (0.53% y ⁻¹), a loss of 50.7% of initial coral cover. Tropical cyclones, coral predation by crown-of-thorns starfish (COTS), and coral bleaching accounted for 48%, 42%, and 10% of the respective estimated losses, amounting to 3.38% y ⁻¹ mortality rate. Importantly, the relatively pristine northern region showed no overall decline. The estimated rate of increase in coral cover in the absence of cyclones, COTS, and bleaching was 2.85% y ⁻¹, demonstrating substantial capacity for recovery of reefs. In the absence of COTS, coral cover would increase at 0.89% y ⁻¹, despite ongoing losses due to cyclones and bleaching. Thus, reducing COTS populations, by improving water quality and developing alternative control measures, could prevent further coral decline and improve the outlook for the Great Barrier Reef. Such strategies can, however, only be successful if climatic conditions are stabilized, as losses due to bleaching and cyclones will otherwise increase.
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