Effects Of Climate Variability Research Articles

Predictive Modelling for Rice Weeds in Climate Change: A Review

Rice (Oryza sativa L.) is an important staple food not only for Asians but also for people worldwide. However, weeds in rice fields can cause yield reduction due to their tendency to compete for resources. These significant biological obstacles can potentially cause complete yield loss if inappropriately managed. In addition, future climate change can cause rice weeds to become more competitive against cultivated rice plants by providing new favourable conditions for the unwanted species to expand aggressively. As the effect of climate change on rice weeds has been studied, the abiotic parameters, including carbon dioxide concentration, atmospheric temperature, drought, and soil salinity, can be used to construct predictive modelling to forecast rice weed infestation. If the weed invasion in rice fields can be predicted accurately based on the weather information, the farmers can prepare the countermeasure early to avoid high yield loss. However, some challenges need to be faced by the researchers as the weed invasion depends not only on the climate condition alone. This review summarizes the effect of climatic variation on weed infestation in rice fields. It also discusses how predictive modelling can be developed based on the information of the environmental conditions and their challenges.

The prospective effects of Climate change on Neglected Tropical Diseases in the Eastern Mediterranean region: A review

BACKGROUND AND AIM: An increase in the annual daily temperature is documented and predicted to occur in the coming decades. Climate change has a direct effect and adverse impact on human health, as well as on multiple ecosystems and their species. The purpose of this paper is to review the effect of climate change on neglected tropical diseases including leishmaniasis, schistosomiasis, and lymphatic filariasis in the Eastern Mediterranean Region (EMR). METHODS: A list of engine web searches was done; 280 full-text records were assessed for eligibility. Only 48 original records were included within the final selection for the review study. RESULTS: Most research results show an alteration of neglected diseases related to climate change influencing specifically the Eastern Mediterranean Region, in addition to the expectation of more effects at the level of vectors and reservoir whether its vector transmission route or its egg hatching and replication or even the survival of adult worms in the coming years. At the same time, not all articles related to the region interpret the direct or indirect effect of climate variations on these specific diseases. CONCLUSION: Although few studies were found describing some of climate change effects on neglected tropical diseases in the region, still, the region lacks research funding, technical, and mathematical model expertise regarding the direct effect of climate change on the ecosystems of these neglected tropical diseases KEYWORDS: climate change, neglected tropical diseases, Eastern Mediterranean region

Decomposing the spatial and temporal effects of climate on bird populations in northern European mountains.

The relationships between species abundance or occurrence versus spatial variation in climate are commonly used in species distribution models to forecast future distributions. Under "space-for-time substitution", the effects of climate variation on species are assumed to be equivalent in both space and time. Two unresolved issues of space-for-time substitution are the time period for species' responses and also the relative contributions of rapid- versus slow reactions in shaping spatial and temporal responses to climate change. To test the assumption of equivalence, we used a new approach of climate decomposition to separate variation in temperature and precipitation in Fennoscandia into spatial, temporal, and spatiotemporal components over a 23-year period (1996-2018). We compiled information on land cover, topography, and six components of climate for 1756 fixed route surveys, and we modeled annual counts of 39 bird species breeding in the mountains of Fennoscandia. Local abundance of breeding birds was associated with the spatial components of climate as expected, but the temporal and spatiotemporal climatic variation from the current and previous breeding seasons were also important. The directions of the effects of the three climate components differed within and among species, suggesting that species can respond both rapidly and slowly to climate variation and that the responses represent different ecological processes. Thus, the assumption of equivalent species' response to spatial and temporal variation in climate was seldom met in our study system. Consequently, for the majority of our species, space-for-time substitution may only be applicable once the slow species' responses to a changing climate have occurred, whereas forecasts for the near future need to accommodate the temporal components of climate variation. However, appropriate forecast horizons for space-for-time substitution are rarely considered and may be difficult to reliably identify. Accurately predicting change is challenging because multiple ecological processes affect species distributions at different temporal scales.

Microclimate influences plant reproductive performance via an antagonistic interaction

Climatic conditions can influence plant reproduction directly, but also via changes in plant traits, interactions with animals, and the surrounding environment. Such indirect effects can often be complex and involve multiple steps including climatic effects on interacting species, and on the context in which these interactions occur. The joint effects of climatic variation and indirect effects in terms of plant-animal interactions have sometimes been assessed at larger spatial scales. However, less is known about how microclimatic variation affects within-population variation in reproductive performance, in spite of that it is becoming increasingly clear that variation in climatic conditions can occur over very short distances. We studied the direct and indirect effects of microclimate on within-population variation in reproductive performance of the plant Gentiana pneumonanthe in presence of the myrmecophagous and seed predator butterfly Phengaris alcon. We found that microclimatic effects on plant performance were mainly indirect, and that effects of temperature and moisture were interactive. The number of seeds per flower of G. pneumonanthe decreased in cold and moist microsites, and these effects were mediated by an increased oviposition by P. alcon in these microsites. The effects of soil temperature and moisture on the incidence of oviposition and plant performance were mediated by effects on plant phenology, density and phenology of neighbouring host plants, and host ant abundance. Plants that flowered earlier and where host ants were more abundant, and especially plants surrounded by fewer and later-flowering neighbours, produced fewer seeds per flower because of a higher incidence of oviposition. Our results demonstrate that effects of microclimatic variation on plant reproductive performance can be mostly indirect and largely mediated by species interactions. These findings highlight that among individual variation in small-scale environmental conditions within populations can cause variation in individual plant performance through multiple pathways.

Does Digital Inclusive Finance Mitigate the Negative Effect of Climate Variation on Rural Residents' Income Growth in China?

Global anthropogenic greenhouse gas emissions have exacerbated climate variation. Climate variation impacts the agricultural production and rural residents’ income negatively, further widening the urban-rural income gap and harming the co-benefits. Narrowing the income gap has always been a global concern and an important part of China’s rural revitalization strategy. However, little is known about whether digital inclusive finance can mitigate the negative impact of climate variation on rural residents’ income growth in China. Using panel data from 31 provinces in China from 2011 to 2019 and a digital inclusive finance index developed by Peking University, together with historical temperature data, this study examined the impact of digital inclusive finance on Chinese rural residents’ income growth in response to climate variation. It was found that digital inclusive finance could promote rural resident operating, wage, and transfer income growth. A heterogeneity analysis revealed that rural residents in central and western regions experienced larger digital inclusive finance facilitating effects on income growth than the eastern regions. Further analyses using the Spatial Dubin Model found that digital inclusive finance had a spatial spillover effect as it could significantly promote income growth in neighboring provinces. Although climate variation reduced rural residents’ income and increased their risks, digital inclusive finance significantly mitigated this negative effect. Digital information infrastructure construction, financial risk prevention, digital financial knowledge, and e-commerce popularization were practical paths to optimizing inclusive finance development in rural areas and promoting poverty alleviation and rural revitalization to resist climate risks.

Different factors limit early- and late-season windows of opportunity for monarch development.

Seasonal windows of opportunity are intervals within a year that provide improved prospects for growth, survival, or reproduction. However, few studies have sufficient temporal resolution to examine how multiple factors combine to constrain the seasonal timing and extent of developmental opportunities. Here, we document seasonal changes in milkweed (Asclepias fascicularis)–monarch (Danaus plexippus) interactions with high resolution throughout the last three breeding seasons prior to a precipitous single‐year decline in the western monarch population. Our results show early‐ and late‐season windows of opportunity for monarch recruitment that were constrained by different combinations of factors. Early‐season windows of opportunity were characterized by high egg densities and low survival on a select subset of host plants, consistent with the hypothesis that early‐spring migrant female monarchs select earlier‐emerging plants to balance a seasonal trade‐off between increasing host plant quantity and decreasing host plant quality. Late‐season windows of opportunity were coincident with the initiation of host plant senescence, and caterpillar success was negatively correlated with heatwave exposure, consistent with the hypothesis that late‐season windows were constrained by plant defense traits and thermal stress. Throughout this study, climatic and microclimatic variations played a foundational role in the timing and success of monarch developmental windows by affecting bottom‐up, top‐down, and abiotic limitations. More exposed microclimates were associated with higher developmental success during cooler conditions, and more shaded microclimates were associated with higher developmental success during warmer conditions, suggesting that habitat heterogeneity could buffer the effects of climatic variation. Together, these findings show an important dimension of seasonal change in milkweed–monarch interactions and illustrate how different biotic and abiotic factors can limit the developmental success of monarchs across the breeding season. These results also suggest the potential for seasonal sequences of favorable or unfavorable conditions across the breeding range to strongly affect monarch population dynamics.

Spatiotemporal Variation in Aboveground Biomass and Its Response to Climate Change in the Marsh of Sanjiang Plain

The Sanjiang Plain has the greatest concentration of freshwater marshes in China. Marshes in this area play a key role in adjusting the regional carbon cycle. As an important quality parameter of marsh ecosystems, vegetation aboveground biomass (AGB) is an important index for evaluating carbon stocks and carbon sequestration function. Due to a lack of in situ and long-term AGB records, the temporal and spatial changes in AGB and their contributing factors in the marsh of Sanjiang Plain remain unclear. Based on the measured AGB, normalized difference vegetation index (NDVI), and climate data, this study investigated the spatiotemporal changes in marsh AGB and the effects of climate variation on marsh AGB in the Sanjiang Plain from 2000 to 2020. Results showed that the marsh AGB density and annual maximum NDVI (NDVImax) had a strong correlation, and the AGB density could be accurately calculated from a power function equation between NDVImax and AGB density (AGB density = 643.57 × NDVI). According to the function equation, we found that the AGB density significantly increased at a rate of 2.47 g·C/m2/a during 2000–2020 in marshes of Sanjiang Plain, with the long-term average AGB density of about 282.05 g·C/m2. Spatially, the largest increasing trends of AGB were located in the north of the Sanjiang Plain, and decreasing trends were mainly found in the southeast of the study area. Regarding climate impacts, the increase in precipitation in winter could decrease the marsh AGB, and increased temperatures in July contributed to the increase in the marsh AGB in the Sanjiang Plain. This study demonstrated an effective approach for accurately estimating the marsh AGB in the Sanjiang Plain using ground-measured AGB and NDVI data. Moreover, our results highlight the importance of including monthly climate properties in modeling AGB in the marshes of the Sanjiang Plain.

On the Exploitation of Remote Sensing Technologies for the Monitoring of Coastal and River Delta Regions

Remote sensing technologies are extensively applied to prevent, monitor, and forecast hazardous risk conditions in the present-day global climate change era. This paper presents an overview of the current stage of remote sensing approaches employed to study coastal and delta river regions. The advantages and limitations of Earth Observation technology in characterizing the effects of climate variations on coastal environments are also presented. The role of the constellations of satellite sensors for Earth Observation, collecting helpful information on the Earth’s system and its temporal changes, is emphasized. For some key technologies, the principal characteristics of the processing chains adopted to obtain from the collected raw data added-value products are summarized. Emphasis is put on studying various disaster risks that affect coastal and megacity areas, where heterogeneous and interlinked hazard conditions can severely affect the population.

Community assembly along climatic gradient: Contrasting pattern between- and within- species

Grime’s CSR classification of functional strategies in terms of competitors, stress-tolerators and ruderals provides a helpful framework for understanding and predicting vegetation responses to environmental changes. To evaluate the importance of alternative processes that structure plant communities, it is useful to disentangle the community functional variation into interspecific and intraspecific components and assess their degree of co-variation. Few efforts have been made to investigate the habitat filtering theory in all the interspecific and intraspecific components of a plant community. We hypothesized that under intense climatic conditions, such as drought and cold, functional diversity would decrease towards the dominance of stress tolerant strategies, and that such trends would be reinforced by similar variation at the intraspecific level. We investigated the effect of climatic variation on functional diversity and on community-weighted mean along an elevation gradient in central Italy that ranges from dry and warm climatic conditions at lower elevation to cold and moist ones at higher elevation. We ran regression models to disentangle the total community components for both functional diversity and community-weighted mean into interspecific effect, intraspecific effect and their covariation along the climatic gradient. Our observations were in line with the theory of habitat filtering: we found lower diversity of the Grime strategy for species at both warmer and colder climatic conditions, with dominance of the stress-tolerant strategy. Similarly, the intraspecific effect was lower in cold conditions but higher under drier conditions, which seems to indicate that different processes act at the level of individuals. Given the important intraspecific variability observed in this study, it can be proposed that investigations of vegetation communities should take the role of intraspecific variability into greater consideration.

Climatic sensitivities derived from tree rings improve predictions of the Forest Vegetation Simulator growth and yield model

Forest management has the potential to contribute to the removal of greenhouse gasses from the atmosphere via carbon sequestration and storage. To identify management actions that will maximize carbon removal and storage over the long term, models are needed that accurately and realistically represent forest responses to changing climate. The most widely used growth and yield model in the United States (U.S.), the Forest Vegetation Simulator (FVS), which also forms the basis for several forest carbon calculators, does not currently include the direct effect of climate variation on tree growth. We incorporated the effects of climate on tree diameter growth by combining tree-ring data with forest inventory data to parameterize a suite of alternative models characterizing the growth of three dominant tree species in the arid and moisture-limited state of Utah. These species, Pinus ponderosa Dougl. ex Laws, Pseudotsuga menziesii var. glauca Mayr (Franco), and Picea engelmannii Parry ex Engelm., encompass the full elevational range of montane forest types. The alternative models we considered differed progressively from the current FVS large-tree diameter growth model, first by changing to an annual time step, then by adding interannual climate effects, followed by model simplification (removal of predictors), and finally, complexification, including effects of spatial variation in climate and two-way interactions between predictors. We validated diameter growth predictions from these models with independent observations, and evaluated model performance in terms of accuracy, precision, and bias. We then compared predictions of future growth made by the existing large-tree diameter growth model used in FVS, i.e., without climate effects, to those of our updated models, including those with climate effects. We found that simpler models of tree growth outperform the current FVS model, and that the incorporation of climate effects improves model performance for two out of three species, in which growth is currently overpredicted by FVS. Diameter growth projected with improved, climate-sensitive models is less than the future tree growth projected by the current climate-insensitive FVS model. Tree rings can be used to identify and incorporate drivers of growth variation into a stand-level growth and yield model, giving more accurate predictions of the carbon uptake potential of forests under climate change.

The Effect of Climatic Variation on Weathering Intensity for the Mineral Composition in Some Iraqi Soils

This study was conducted to find out the effect of variation in the nature of climatic conditions and physiographic location on the weathering intensity of the mineral composition in some Iraqi soils. Six different locations were selected within rainfall with intensity ranged between 100-1200 mm/year, located in the north, west, central and southern Iraq. These locations were represented by the governorates of Erbil and Sulaymaniyah, Salah al-Din, Wasit and Dhi Qar in the locations of (Joman, Halabja, Al-Sharqat, Tikrit, Al-Suwaira project, and Hor Al-Jbayish) respectively. The scanning electron microscope (SEM) was used to diagnose the most important morphological features of clay minerals. Moreover, the examination results of clays in northern Iraq showed the presence of mica minerals in their irregular lamellar shape with rough surfaces containing cracks. These features reflected the exposure of mica minerals to different stages of weathering intensity of the layers, as well as it was exposed to the edges weathering in some of its areas. Likewise, the surfaces of these minerals seemed to contain slab elongated particles of regular geometric shape and with curled edges that belong to other minerals that are considered as impurities within the composition of the original mineral during the formation process. Besides, a transformation of part of the mica minerals appeared towards the expanded minerals 1:2 most likely to be Smectite minerals. As for the clays of the western regions of Iraq, the mica mineral particles appeared with multiple morphological appearances within the weathering of layers and edges. The surfaces of those particles appeared rough with the presence of the layers Splitting accompanied by peeling, which indicates the exposure of these minerals to layers weathering. Furthermore, the results of general examination of the particles showed the absence of sharp edges rather, and some of them had irregular edges as a result of breaking the metal flakes as they were subjected to physical weathering in conjunction with chemical weathering. Plus, the presence of a shift at the edges of the mica minerals towards the expanded Smectite minerals 1:2. The latter appeared in the form of a white cloud, in addition to the presence of mica minerals with the weathered edges, but it appeared in a limited way, which reflects the extent of the decrease in the effective weathering intensity in those areas. The particles of the Palygorskite mineral appeared in an elongated shape, which reflects the appropriateness of the environmental conditions in those areas to form it, as it is a gypsum soil in nature. As for the clays of the central regions of Iraq, mica minerals appeared in the form of unaffected surfaces and the edges of some of them weathered and may have been weathered by transport and sedimentation processes. Otherwise, at the source, the conditions of the sampling areas do not encourage the occurrence of weathering processes as they are dry or semi-dry areas with little rain. Similarly, it may be caused by wind weathering, and chlorite minerals appeared in a pseudo hexagonal form, and Smectite minerals appeared in a white cloudy form. At the time, the clays of the southern regions of Iraq - Hor Al-Jbayish showed that a large part of the surfaces of their minerals were irregular. However, the surfaces of the mica minerals contained holes of different sizes and that some of those mineral surfaces had appeared in a spongy form. Moreover, the holes that had been observed on the surfaces of Mica minerals can be the result of the presence of impurities from fossilized plant. Otherwise, animal remains during the synthesis of the mineral, which left a hole after the process of its complete dissolution. Similarly, it may be the result of the mineral impurity in the presence of impurities of other minerals that may differ in their geological age and degree of resistance to weathering. In general, all these morphological features are a product of what these minerals are exposed to from the weathering processes, whether they are water or wind in the source areas or during transport and deposition.

Impacts of Climatic Variation on Water Balance and Yield of Watershed (Insights from The Kaduna Watershed, North Central Nigeria)

Many authors have identified climate variation impacts in Nigeria. However, the effects on water balance and water yield have not been thoroughly considered. Good knowledge of water balances is vital for sustainable water resource management in northern Nigeria due to high water stress and increased evapotranspiration compared to another part of the country. Hence, the study presents the first detailed climatic variation impacts on watershed water balance and water yield in north-central Nigeria. Soil and Water Assessment Tool (SWAT) was applied to predict the hydrological procedures. The Kaduna watershed (32,124 km2) calibrated and validated streamflow results were run independently using three land cover maps of 1975, 2000, and 2013. The model performance evaluation was statically attained using the coefficient of determination (r2), Nash-Sutcliffe (NS), besides the percentage of observed data (p-factor). The model evaluation result of r2 (0.80), NS (0.71), and p-factors of 0.86 indicated the model satisfactory performance evaluation of streamflow predictions. The streamflow estimation revealed Threshold depth of water (GWQMN.gw) as the most sensitive parameter. The findings discovered declined between 1975 and 2013 in precipitation, water yield, surface runoff (SURQ_mm), lateral flow (LAT_Qmm), deep aquifer (Deep_mm) by 4.2%, 37.3%, 56%, 15%, and 100% respectively, while shallow groundwater aquifer (GW_Qmm) experienced 10% decrease between 1975 and 2000 and appreciated by 6% between 2000 and 2013, evapotranspiration (ET_mm) increase by about 22.2% between 1975 and 2013. These results suggest considerable effects of climate variation in the watershed and call for further investigation to mitigate climate change influence.

Climate variability, water supply, sanitation and diarrhea among children under five in Sub-Saharan Africa: a multilevel analysis.

Climate variability is expected to increase the risk of diarrhea diseases, a leading cause of child mortality and morbidity in Sub-Saharan Africa (SSA). The risk of diarrhea is more acute when populations have poor access to improved water and sanitation. This study seeks to determine individual and joint effects of climate variation, water supply and sanitation on the occurrence of diarrhea among children under five in SSA using multilevel mixed-effect Poisson regression including cross-level interaction. We merged 57 Demographic and Health Surveys (DHS) from 25 SSA countries covering the period 2000-2019 with climatic data from the DHS geolocation databases. The results of the research indicate that 77.7% of the variation in the occurrence of diarrhea in Sub-Saharan households is due to climatic differences between clusters. Also, a household residing in a cluster with a high incidence of diarrhea is 1.567 times more likely to have diarrhea cases than a household from a cluster with a low incidence. In addition, when average temperature and rainfall increase, households using unimproved sanitation or unimproved water have more cases of diarrhea. For SSA, the results of the multilevel analysis suggest the adoption at both levels; macro (national) and micro (household), of climate change adaption measures in the water sector to reduce the prevalence of diarrhea.

The Prospective Effects of Climate Change on Neglected Tropical Diseases in the Eastern Mediterranean Region: a Review.

An increase in the annual daily temperature is documented and predicted to occur in the coming decades. Climate change has a direct effect and adverse impact on human health, as well as on multiple ecosystems and their species. The purpose of this paper is to review the effect of climate change on neglected tropical diseases including leishmaniasis, schistosomiasis, and lymphatic filariasis in the Eastern Mediterranean Region (EMR). A list of engine web searches was done; 280 full-text records were assessed for eligibility. Only 48 original records were included within the final selection for the review study. Most research results show an alteration of neglected diseases related to climate change influencing specifically the Eastern Mediterranean Region, in addition to the expectation of more effects at the level of vectors and reservoir whether its vector transmission route or its egg hatching and replication or even the survival of adult worms in the coming years. At the same time, not all articles related to the region interpret the direct or indirect effect of climate variations on these specific diseases. Although few studies were found describing some of climate change effects on neglected tropical diseases in the region, still, the region lacks research funding, technical, and mathematical model expertise regarding the direct effect of climate change on the ecosystems of these neglected tropical diseases.

Climate effect on Avena fatua field emergence dynamics: A 38‐year experiment in the semiarid Pampean region of Argentina

Climate events modulate weed population dynamics mainly by influencing field seedling emergence patterns. Field experiments aiming to study the influence of climate on the early-stage establishment of weeds are of utmost importance from a practical and strategic decision-making management point of view. The objective of this study was to analyse the effect of climate variations on the field emergence dynamics of Avena fatua in the southwest area of the semiarid Pampean region of Argentina. Field emergence patterns of A. fatua were monitored from 1977 to 2015. Seedling counts were destructively sampled at weekly intervals. Three quadrats (1 m2 each) were randomly distributed on a 5 ha experimental field with a high natural population density of A. fatua in the absence of a crop. Results show that the emergence strategy of this species is highly plastic with a striking variation in response to year-to-year climate signals. Avena fatua field emergence strategies were classified as staggered, early, medium and late based on both chronological and hydrothermal-time parameters. In the short-term, precipitation regimes during both the after-ripening and emergence phases largely explained the resulting emergence strategy. In the long-term, the combined effect of a reduction in both the precipitation frequency and the mean minimum temperature correlated with an increase in the staggered emergence pattern. Results also point out the adaptability of A. fatua in the area under study, further suggesting a bet-hedging fitness strategy that could diminish the risk of population decline under changing climate scenarios. From an agronomic perspective, the occurrence of staggered emergence patterns with an extended emergence window would complicate the definition of the optimal time for weed control. Thus, tailoring decisions based on the Southern Oscillation Index (SOI) episodes (neutral, negative or positive) forecast plus the implementation of weed emergence models could lead to more accurate and sustainable weed management decisions.

Effects of Environmental Factors on the Changes in MODIS NPP along DEM in Global Terrestrial Ecosystems over the Last Two Decades

Global warming has exerted widespread impacts on the terrestrial ecosystem in the past three decades. Vegetation is an important part of the terrestrial ecosystem, and its net primary productivity (NPP) is an important variable in the exchange of materials and energy in the terrestrial ecosystem. However, the effect of climate variation on the spatial pattern of zonal distribution of NPP has remained unclear over the past two decades. Therefore, we analyzed the spatiotemporal patterns and trends of MODIS NPP and environmental factors (temperature, radiation, and soil moisture) derived from three sets of reanalysis data. The moving window method and digital elevation model (DEM) were used to explore their changes along elevation gradients. Finally, we explored the effect of environmental factors on the changes in NPP and its elevation distribution patterns. Results showed that nearly 60% of the global area exhibited an increase in NPP with increasing elevation. Soil moisture has the largest uncertainty either in the spatial pattern or inter-annual variation, while temperature has the smallest uncertainty among the three environmental factors. The uncertainty of environmental factors is also reflected in its impact on the elevation distribution of NPP, and temperature is still the main dominating environmental factor. Our research results imply that the carbon sequestration capability of vegetation is becoming increasingly prominent in high-elevation regions. However, the quantitative evaluation of its carbon sink (source) functions needs further research under global warming.

Landscape composition, climate variability, and their interaction drive waterfowl nest survival in the Canadian Prairies

AbstractFor upland‐nesting ducks that rely on grassland and wetland habitats in landscapes characterized by human alteration and a strongly fluctuating climate, information on how landscape composition interacts with climate is needed to better understand the security of conservation investments and to inform adaptive management in a changing climate. We characterized spatial and temporal variation in a 10‐year study of nest survival of five species of upland‐nesting ducks at study areas across the Canadian Prairie Pothole Region. We assessed factors affecting nest survival across gradients of landscape composition, climate, and duck density. Habitat characteristics influenced nest survival at multiple scales spanning nest‐scale vegetation density to landscape‐scale perennial cover abundance, with the relative magnitude of spatial variation in nest survival greater than that of temporal variation in this study. An interaction between climate and landscape composition suggested that intact landscapes can moderate the effects of interannual variation in climate, reinforcing the importance of habitat conservation in a changing climate. Measured nest survival rates ranged from 4.7% to 40.5% and were high enough to sustain duck populations in only 31% of study areas, barring sustained climatic conditions suitable for elevating other breeding season vital rates, suggesting the need for continued investment in waterfowl conservation.

The Dominant Driving Force of Forest Change in the Yangtze River Basin, China: Climate Variation or Anthropogenic Activities?

Under the combined effect of climate variations and anthropogenic activities, the forest ecosystem in the Yangtze River Basin (YRB) has experienced dramatic changes in recent decades. Quantifying their relative contributions can provide a valuable reference for forest management and ecological sustainability. In this study, we selected net primary productivity (NPP) as an indicator to investigate forest variations. Meanwhile, we established eight scenarios based on the slope coefficients of the potential NPP (PNPP) and actual NPP (ANPP), and human-induced NPP (HNPP) to quantify the contributions of anthropogenic activities and climate variations to forest variations in the YRB from 2000 to 2015. The results revealed that in general, the total forest ANPP increased by 10.42 TgC in the YRB, and forest restoration occurred in 57.25% of the study area during the study period. The forest degradation was mainly observed in the Wujiang River basin, Dongting Lake basin, and Poyang Lake basin. On the whole, the contribution of anthropogenic activities was greater than climate variations on both forest restoration and degradation in the YRB. Their contribution to forest restoration and degradation varied in different tributaries. Among the five forest types, shrubs experienced the most severe degradation during the study period, which should arouse great attention. Ecological restoration programs implemented in YRB have effectively mitigated the adverse effect of climate variations and dominated forest restoration, while rapid urbanization in the mid-lower region has resulted in forest degradation. The forest degradation in Dongting Lake basin and Poyang Lake basin may be ascribed to the absence of the Natural Forest Conservation Program. Therefore, we recommend that the extent of the Natural Forest Conservation Program should expand to cover these two basins. The current research could improve the understanding of the driving mechanism of forest dynamics and promote the effectiveness of ecological restoration programs in the YRB.

Quantifying the impacts of climate variation, damming, and flow regulation on river thermal dynamics: a case study of the W\u0142oc\u0142awek Reservoir in the Vistula River, Poland

BackgroundRiver damming inevitably reshapes water thermal conditions that are important to the general health of river ecosystems. Although a lot of studies have addressed the damming’s thermal impacts, most of them just assess the overall effects of climate variation and human activities on river thermal dynamics. Less attention has been given to quantifying the impact of climate variation, damming and flow regulation, respectively. In addition, for rivers that have already faced an erosion problem in downstream channels, an adjustment of the hydroelectric power plant operation manner is expected, which reinforces the need for understanding of flow regulation’s thermal impact. To fill this gap, an air2stream-based approach is proposed and applied at the Włocławek Reservoir in the Vistula River in Poland.ResultsIn the years of 1952–1983, downstream river water temperature rose by 0.31 ℃ after damming. Meanwhile, the construction of dam increased the average annual water temperature by 0.55 ℃, while climate change oppositely made it decreased by 0.26 ℃. In addition, for the seasonal impact of damming, autumn was the most affected season with the warming reached 1.14 ℃, and the least affected season was winter when water temperature experienced a warming of 0.1 ℃. The absolute values of seasonal average temperature changes due to flow regulation were less than 0.1 ℃ for all the seasons.ConclusionsThe impacts of climate variation, damming, and flow regulation on river water temperatures can be evaluated reasonably on the strength of the proposed methodology. Climate variation and damming led to general opposite impacts on the downstream water temperature at the Włocławek Reservoir before 1980s. It is noted that the climate variation impact showed an opposite trend compared to that after 1980s. Besides, flow regulation below dam hardly affected downstream river water temperature variation. This study extends the current knowledge about impacts of climate variation and hydromorphological conditions on river water temperature, with a study area where river water temperature is higher than air temperature throughout a year.

Divergent responses of terrestrial carbon use efficiency to climate variation from 2000 to 2018

Carbon use efficiency (CUE) refers to the allocation of photosynthesized products by plants and is commonly used to measure primary production in terrestrial ecosystems. Despite the fact that the effects of climate variation on vegetation CUE have been studied at various spatial scales, there is still a lack of consensus as to how vegetation CUE responds to climate factors. The objective of this study was to evaluate the spatiotemporal dynamics of terrestrial CUE based on the latest versions of Moderate Resolution Imaging Spectroradiometer (MODIS) products during 2000–2018, and to reveal the dominant climate factor that controls vegetation CUE in different regions by using path analysis (PA). The results showed that global vegetation CUE increased significantly due to a more rapid increase in net primary productivity (NPP) than in gross primary productivity (GPP) over this period. Central Africa and South America are the two areas that experienced clear increases in CUE, and Amazon and northeastern India experienced decreases in vegetation CUE due to reduced precipitation. CUE increased significantly in the north frigid, the torrid, and the south temperate zones over this period. The largest areas showing vegetation CUE increases and decreases occurred in the north temperate zone. Rising precipitation lowered the vegetation CUE in the north frigid zone, but promoted CUE increase in the torrid and south temperate zones. Higher temperatures led to higher CUE in the north frigid and south temperate zones. Reduced CUE due to higher temperature mostly occurred in the arid zones. CUE in the cold/boreal zone remained relatively stable due to the synchronized variation of GPP and NPP. The divergent responses of terrestrial CUE to climate variations call for flexible ecosystem management to adapt to the future warming climate in different regions. The results also highlighted that a dynamic parameterization scheme of vegetation carbon allocation should be considered in simulating the terrestrial C cycle in Earth System Models.