Decrease In Annual Precipitation Research Articles

Floods and related problems after the 1980s in Khovd, Western Mongolia

AbstractGlobal warming has increased flood hazards, even in semi-arid regions. The extremely low normal surface water flow in these regions complicates hazard assessment and flood risk awareness. In this study, we first investigated recent flood trends since the 1980s in the major city of Khovd using meteorological data and satellite images to clarify climate change and its impacts in western Mongolia, which have not been reported before. The results showed that the frequency of heavy rain has increased gradually, despite a significant decrease in total annual precipitation. 75% of the total precipitation in the city of Khovd occurs in summer. Moreover, the frequency of daily precipitation exceeding 10 mm and the maximum daily precipitation have increased, and the frequency of flooding has increased since 1987. We also found that traces of floods were clearly recorded in Landsat images nine times since 1992 to 2022. The Buyant River, which flows northward along the western edge of Khovd, has not flooded in the past few decades, but flash floods flowing directly down from the southern mountains have struck Khovd. The study also revealed poor flood control structures and a lack of knowledge among residents. As a Mongolian custom, many residents spend the summer in gers (mobile living tent) along the Buyant River, and the increase in the flow rate of the Buyant River over the past few decades further increases the risk of disaster. To reduce the increasing risk, it is necessary to strengthen flood control facilities and raise awareness pertaining to the lifestyles of local residents. This example is likely to be universal for reducing flood risk in semi-arid Asia.

Studies on Heavy Precipitation in Portugal: A Systematic Review

This systematic review, based on an adaptation of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement from 2020, focuses on studies of the atmospheric mechanisms underlying extreme precipitation events in mainland Portugal, as well as observed trends and projections. The 54 selected articles cover the period from 2000 to 2024, in which the most used keywords are “portugal” and “extreme precipitation”. Of the 54, 23 analyse trends and climate projections of precipitation events, confirming a decrease in total annual precipitation, especially in autumn and spring, accompanied by an increase in the frequency and intensity of extreme precipitation events in autumn, spring and winter. Several articles (twelve) analyse the relationship between synoptic-scale circulation and heavy precipitation, using an atmospheric circulation types approach. Others (two) establish the link with teleconnection patterns, namely the North Atlantic Oscillation (NAO), and still others (three) explore the role of atmospheric rivers. Additionally, five articles focus on evaluating databases and Numerical Weather Prediction (NWP) models, and nine articles focus on precipitation-related extreme weather events, such as tornadoes, hail and lightning activity. Despite significant advances in the study of extreme precipitation events in Portugal, there is still a lack of studies on hourly or sub-hourly scales, which is critical to understanding mesoscale, short-lived events. Several studies show NWP models still have limitations in simulating extreme precipitation events, especially in complex orography areas. Therefore, a better understanding of such events is fundamental to promoting continuous improvements in operational weather forecasting and contributing to more reliable forecasts of such events in the future.

Investigating a Century of Rainfall: The Impact of Elevation on Precipitation Changes (Northern Tuscany, Italy)

Precipitation is crucial for water resource renewal, but climate change alters their frequency and amounts, challenging societies for correct and effective water management. However, modifications of precipitation dynamics appear to be not uniformly distributed, both in space and time. Even in relatively small areas, precipitation shows the coexistence of positive and negative trends. Local topography seems to be a strong driver of precipitation changes. Understanding precipitation changes and their relationship with local topography is crucial for society’s resilience. Taking advantage of a dense and long-lasting (1920–2019) meteorological monitoring network, we analyzed the precipitation changes over the last century in a sensitive and strategic area in the Mediterranean hotspot. The study area corresponds to northern Tuscany (Italy), where its topography comprises mountain ridges and coastal and river plains. Forty-eight rain gauges were selected with continuous annual precipitation time series. These were analyzed for trends and differences in mean annual precipitation between the stable period of 1921–1970 and the last 30-year 1990–2019. The relationship between precipitation changes and local topography was also examined. The results show the following highlights: (i) A general decrease in precipitation was found through the century, even if variability is marked. (ii) The mountain ridges show the largest decrease in mean annual precipitation. (iii) The precipitation change entity over the last century was not homogenous and was dependent on topography and geographical setting. (iv) A decrease in annual precipitation of up to 400 mm was found for the mountainous sites.

Projected changes of thermal, rainfall and drought indices in Morocco from high resolution climate models

Abstract Over the past decade, global changes in temperature, average and extreme precipitation have been observed many times. The increase in temperature or even the change in precipitation systems is directly affect extreme weather events, for example, heat waves, heavy rainfall, storms, and droughts are becoming more frequent and more powerful worldwide due to climate change caused by several factors including human activity. This is why there is a necessity to monitor future changes in climate extremes. The objective of this paper is to evaluate the future changes in thermal and rainfall extremes projected by the four climate models over time horizon 2041-2060 relative to the 1981-2010 reference period, based on the 5 climate indices, including Tmm, Tx90p, WSDI, PRCPTOT and SPI. The projections are given under the RCP 4.5 medium scenario. The analysis in thermal aspect shows that Morocco could experience by 2041-2060, a significant warming, has manifested by an increase in average temperature. Future changes in rainfall indices show that the spatial distribution of rainfall in Morocco could change significantly by 2041-2060 compared to the reference period 1971-2010. The four climate models agree on a decrease in annual precipitation that could affect most of the Kingdom. In the same way to dryness, the future changes of the SPI index that characterizes the drought, indicates a move to a dry climate.

Long-term meteorological characteristics and extreme climate indices over Tirupati: a rapidly developing tropical city

Tirupati’s climate has undergone significant changes in both temperature and precipitation patterns. While there has been a consistent increase in rainfall during the southwest monsoon, there is a concerning long-term trend of a decrease in total annual precipitation over the last 30 years. The city has experienced a rise in wet days during both the southwest and northeast monsoons, yet a recent decrease over the past three decades. Heavy precipitation events, particularly during the southwest monsoon, have shown a positive trend, whereas there have been no significant changes in heavy rainfall days during the northeast monsoon. Temperature trends reveal that there has been a warming scenario, with a significant positive trend in annual maximum temperatures and a consistent annual rise in mean minimum temperatures. A substantial decrease in cold and very cold days, especially during the last 30 years, suggests a broader warming trend impacting seasonal temperature variations in Tirupati. These findings highlight the complex interplay of monsoons, temperature variations, and changing precipitation patterns in Tirupati's climate over the years.

Mapping forest phenological shift in Nilgiri Biosphere Reserve, Western Ghats: Response to climate change

In the present study, the spatiotemporal alterations in phenological metrics were analyzed in different forest types of Nilgiri Biosphere Reserve (NBR), Western Ghats, India with special reference to the impacts of changing climate on the forest phenology over two-phase periods (Phase 1: 2001–2010 and Phase 2: 2011–2020). Three phenological measures including the start/end/length of the season (SOS/EOS/LOS) were obtained using 16 days of MODIS Enhanced Vegetation Index (EVI) dataset over the two decades. The study exhibited a gradual delay in SOS during phase 1, and an advancing SOS during phase 2 in the tropical forests of NBR. Delayed EOS was observed in all forest types in NBR barring Moist Deciduous Forests (MDF) during phase 1, while opposite trend of advancing EOS was observed in deciduous forests (MDF and DDF: Dry Deciduous Forests), but delayed EOS was observed in evergreen forests (SEF: Semi Evergreen Forests and WEF: Wet Evergreen Forests) during phase 2. These variations in forest phenology are linked with an increase in annual mean temperature (0.01 °C year−1) along with a decrease in annual mean precipitation (3.97 mm year−1) during 1950–2018 as observed using IMD-based meteorological datasets. The results highlighted reduction in the total LOS with a delayed SOS and advanced EOS in NBR, which were prevalent during phase 1 conversely to phase 2 due to the varied intensity of changes in climatic conditions. However, disaggregating decade-long intervals into 5-year segments enables a finer resolution analysis of phenological trends. The study contributes to the development of long-term strategies for forest ecosystem restoration under the influence of global climate change by providing an insightful understanding of the non-systematic shifts in forest phenology attributed by rising warming impacts and erratic precipitation patterns.

Structure and Trends in Climate Parameters of Wine-Growing Regions in Slovenia

This study examined the structure and trends of climate parameters important for grape production from 1952 to 2022 in the wine-growing regions of Podravje, Posavje, and Primorska in Slovenia. Average and extreme temperature and precipitation data from six meteorological stations in three wine-growing regions were divided into annual and growing seasons. The results show that in the period 1991–2022, there was a warming in the growing season in all regions by 1.4–1.7 °C, except the southern part of Primorska (Koper station) 0.6 °C, compared to the reference period 1961–1990. The heat accumulation indices (GDDs and HI) increased significantly, which is mainly due to the increase in the maximum temperature in the growing season temperature (GST max) and the number of days with Tmax > 30 °C (NDT30). The NDT30 increased the most, by a factor of more than four. In the reference period (1961–1990), however, the trend in the number of hot days was even slightly negative. The mean seasonal temperature rose to around 17 °C in regions with a continental climate and to around 19 °C in the Mediterranean region, which could be reflected in the earlier ripening of the grapes. The trends show a decrease in total annual precipitation (AP) after 1991, but this was significant only at one inland location (Maribor), while the total precipitation during the growing season (GSP) decreased significantly at three locations (Maribor, Bilje, and Koper).

Biochar effects on crop yield variability

Context or ProblemNumerous studies have demonstrated that biochar application can increase crop yield by improving soil properties and health. Yet, these studies, however, neglected how biochar alters yield variability across years – reflecting the yield stability. Objective or Research questionThis study aimed to investigate the effects of biochar application on crop yield variability. MethodsPublished data from 38 experimental sites were collected from the Web-of-Science. Two-thirds of the data were originated from three main staple crops: maize, wheat, and rice. The remaining were from rapeseed, soybean, sweet potato, and peppermint. Biochar effects on crop yield and its variability as well as their driving factors were analyzed by linear mixed models depending on soil conditions, field management practices, and climate types. ResultsBiochar increased the crop yield globally by 14 %, especially in soils with low pH (< 5.5), low nitrogen (N) and phosphorus (P) inputs (≤ 120 kg N ha−1, < 35 kg P ha−1), with high biochar inputs (≥ 20 Mg ha−1), and under crop rotation. Biochar increased crop yields by 12 % in short-term (≤ 5 years) and 21 % in long-term (> 5 years) experiments. Biochar increased yield variability by 42 % in acidic soils (pH < 5.5) and by 24 % with low N inputs (≤ 120 kg N ha−1), mainly because its liming and fertilization effects were short-lasting within the first few years. The yield variability after biochar application decreased with the increase in mean annual temperature, inter-annual variabilities of temperature and precipitation, but with the decrease in mean annual precipitation in the growing season. Yield variability under biochar increased in short-term experiments by 27 %, but there was no change (0 %) in long-term experiments because of the higher yield gains and resistance to fluctuating weather conditions. Therefore, crop yield variability decreased with increasing yield in long-term experiments. ConclusionsBiochar application increased short-term variability of crop yields, but its long-term variability remained unaffected. Implications or SignificanceThis study highlights that biochar can support steadily future crop production in the long run.

Integrated hydrological modeling and water resource assessment in the Mayurakshi River Basin: A comprehensive study from historical data to future predictions

This study employs the SWAT hydrologic model to integrate climatological and hydrological processes for an in-depth analysis of the Mayurakshi River Basin. Utilizing the Markov chain model, the study evaluates water availability, flow patterns, and the basin's response to various climatic and land-use scenarios. Over 30 years of daily observed river discharge data were rigorously calibrated, validated, and analyzed for uncertainty, with critical data from the Massanjore Dam and Tilpara Barrage gauge stations characterizing the river's hydrological behavior. The result suggests the watershed received an average annual precipitation of 1432.4 mm, with evapotranspiration accounting for 40% of total water loss (578.4 mm). Surface runoff constituted over 90% of the total discharge, highlighting its importance for agricultural practices, particularly during the dry season. However future projections (2021–2031) indicate a significant decrease in mean annual precipitation (1404.7 mm) and a drop in evapotranspiration (542.1 mm or 38% of mean precipitation), attributed to reduced vegetation cover and increased settlement, leading to enhanced surface runoff. By quantifying internal renewable blue water, evapotranspiration, and soil water, this research provides crucial data for long-term water resource planning and assessment. The findings are valuable for national, regional, and transboundary water management agencies, offering insights into sustainable water resource management under changing climatic and different land-use conditions.

Spatial and Temporal Trends in Precipitation and Temperature and their Influence on Groundwater in Ballia

A study examined the impact of long-term pre- and post-monsoon precipitation and temperature on groundwater level fluctuations in 17 blocks of Ballia District. The study used 100 years of daily precipitation data (1917-2016) and 62 years of daily temperature data (1951-2012) from the Indian Meteorological Department. Seasonal analysis was performed using pre-monsoon, monsoon, post-monsoon, and winter data. The Mann-Kendall method and Sen's slope were applied. The spatial variability of rainfall and temperature was mapped using the IDW technique in ArcGIS. Significant annual precipitation decreases were found in Murlichapra and Sear blocks. Maniar and Pandah blocks showed precipitation increases. An increasing pre-monsoon trend was observed in several blocks, while post-monsoon trends varied. Groundwater levels fluctuated across Ballia, with a notable decrease of 2.1 m in Bairia Block from 2006 to 2016.

The combined impact of climate change scenarios and land use changes on water resources in a semi-arid watershed

This study proposes a combined approach involving climate change scenarios and varied land use and land cover (LULC) projections in a semi-arid watershed (El Grou) located in Morocco. The Soil and Water Assessment Tool (SWAT) model was coupled with land use scenarios generated using the Cellular Automata-Markov model for three dates (2030, 2040, and 2050) and future climate projections from the CMIP5 model under RCP 4.5 and 8.5 scenarios. Future precipitation and temperature projections indicate a decrease in annual precipitation by 5 % to 34 % and an increase in average temperatures, particularly during the summer months. LULC changes reveal a significant decline in agricultural lands and forests, with an expansion of bare soil by 2050. These changes, analyzed through three SWAT models representing different time periods, indicate a decrease in surface runoff by 41 % to 73 %, a reduction in total water yield by 21 % to 53 %, and a decline in groundwater recharge, posing significant challenges for water resource management and ecosystem health. The study underscores the need for integrated land and water management strategies, incorporating climate change adaptation measures, to ensure sustainable water resource utilization and build resilience in the El Grou watershed and similar semi-arid regions.

The impact of precipitation changes on the safety of railway operations in China under the background of climate change

Global climate change has intensified the water cycle, leading to frequent extreme precipitation events, posing a significant threat to railway infrastructure and safety operations. Based on the analysis of past and future precipitation changes in China, this study investigates the impact of climate change on railway safety operations. The study reveals the following findings: (1) Under the influence of the intensified East Asian summer monsoon and the northward shift of the subtropical high during the 2017–2021 compared to the 2012–2016, precipitation has significantly decreased (120 mm) in the regions south of the Yangtze River and South China, while it has increased (60 mm) in the regions from the eastern of Northwest China to the middle and lower reaches of Yangtze River; The operational precipitation risk has decreased for Urumqi, Lanzhou, Qinghai-Tibet Group, Xi’an, and Wuhan railway bureaus (abbreviated as Bureau), while it has increased for Nanchang, Chengdu, Zhengzhou, Shanghai, and Shenyang Bureaus. Particularly noteworthy is that despite a decrease in total annual precipitation for Nanchang bureau (15.3 mm/a), the frequency of intense precipitation events has increased, leading to an increased operational precipitation risk. (2) During the 21st century, under high (SSP5-8.5), medium (SSP2-4.5), and low (SSP1-2.6) forcing scenarios, all projections indicate that most of the China will experience an increasing trend in precipitation, with significant increases in precipitation observed in the regions south of the Yangtze Rive, South and Southwest China. The higher the greenhouse gas emissions, the more pronounced the increasing trend in precipitation. (3) Compared to the 20th century, under high (SSP5-8.5), medium (SSP2-4.5), and low (SSP1-2.6) forcing scenarios, all projections indicate that the total annual precipitation hours, railway inspection, speed limit, and closure risk hours have all increased on a national scale during the 21st century. The operational precipitation risk for railways has also increased. The higher the alert level for railway precipitation (precipitation &amp;lt; inspection &amp;lt; speed limit &amp;lt; closure), the higher the proportion of risk hours compared to the 20th century. By the late 21st century, the railway inspection, speed limit, and closure risk hours have increased by 175%, 463%, and 647%, respectively, compared to the 20th century.

Analysing the Evidence of the Effects of Climate Change, Air Pollutants, and Occupational Factors in the Appearance of Cataracts

Cataracts are ocular conditions characterized by the opacification of the natural lens within the eye, which develops gradually over time and can affect one or both eyes. This condition commonly results from age-related changes in the lens, but can also arise from various factors. Cataract surgeries are expensive, particularly in states such as Spain, where they receive full support from the Spanish social welfare system. Despite a significant body of research on cataracts, few studies address the social and environmental factors triggering their development or consider the spatiotemporal evolution of their impacts. We analysed the incidence of cataracts in a southern region of Spain, differentiating between senile cataracts (those over 60 years old) and early cataracts (those between 15 and 59 years old). Twenty-one socio-economic, climate, and air pollution variables were statistically analysed using bivariate correlation, cluster analysis, and Geographic Information Systems. Eleven years of observation show a decadal increase in annually averaged maximum temperature and a decrease in annual precipitation, partially explaining the rising incidence of operable cataracts in the following year (r = 0.77 and −0.84, respectively; p &lt; 0.05). Furthermore, early cataracts responded spatially to % agricultural employment (r = 0.85; p &lt; 0.05) and moderately to maximum temperatures, insolation, and various constituents.

The Spatio-Temporal Dynamics of Water Resources (Rainfall and Snow) in the Sierra Nevada Mountain Range (Southern Spain)

This paper describes the use of a unique spatio-temporally resolved precipitation and temperature dataset to assess the spatio-temporal dynamics of water resources over a period of almost seven decades across the Sierra Nevada mountain range, which is the most southern Alpine environment in Europe. The altitude and geographical location of this isolated alpine environment makes it a good detector of climate change. The data were generated by applying geostatistical co-kriging to significant instrumental precipitation and temperature (minimum, maximum and mean) datasets. The correlation between precipitation and altitude was not particularly high and the statistical analysis yielded some surprising results in the form of mean annual precipitation maps and yearly precipitation time series. These results confirm the importance of orographic precipitation in the Sierra Nevada mountain range and show a decrease in mean annual precipitation of 33 mm per decade. Seasonality, however, has remained constant throughout the period of the study. The results show that previous studies have overestimated the altitudinal precipitation gradient in the Sierra Nevada and reveal its complex spatial variability. In addition, the results show a clear correspondence between the mean annual precipitation and the NAO index and, to a much lesser extent, the WeMO index. With respect to temperature, there is a high correlation between minimum temperature and altitude (coefficient of correlation = −0.84) and between maximum temperature and altitude (coefficient of correlation = −0.9). Thus, our spatial temperature maps were very similar to topographic maps, but the temporal trend was complex, with negative (decreasing) and positive (increasing) trends. A dynamic model of snowfall can be obtained by using the degree-day methodology. These results should be considered when checking the local performance of climatological models.

Impact of urban dynamics and climate change on forest areas the Maamora forest in the city of Kenitra, Morocco

Studies have focused on the issue of drought on one hand, and urban dynamics on the other, as prominent topics in physical geography for the former, which specializes in climate change, and human geography for the latter, which concerns field sciences. This research is part of a series of studies and specifically relates to a wetland area in the western plain, specifically Maamora Forest in the city of Kenitra. This research addresses three main axes: the first axis relates to human factors contributing to the reduction and deterioration of Maamora Forest over the past three decades and analyzes their impact on the forest. This is done by determining the development and dynamics of cork oak through remote sensing data, manifested in the analysis of aerial images from three different periods (1975, 1995, and 2022), complemented by field research throughout the period between 2022 and 2023. The second axis focuses on studying climatic data for the studied area, extending from 1987 to 2019. It highlights the manifestations of climate change, such as a decrease in annual precipitation and an increase in temperatures, and their impacts on the overall forest and specifically on cork oak trees. This is done using the LANG equation. The results indicate that the region has experienced four dry periods, accounting for 87.5% of the total 28 years, which range from 1987/1988 to 1995/1994, 1997/1998 to 2010/2011, 2012/2013 to 2014/2015, and 2016/2017 to 2018/2019. In contrast, the percentage of semi-humid and extremely dry years only accounted for 6.25% each, with an average duration of two years. The third axis relates to monitoring the effects of climate change on the forestry sector, specifically the Maamora Forest, through the use of modern techniques such as remote sensing and spectral plant and water indicators. It aims to understand the role of these technologies in spatial monitoring of factors and phenomena that negatively impact forest areas in general, and the Maamora Forest in particular.

Yield stability of winter wheat in intercrop makes better adaptation to climate conditions

Global climate change is a main issue today. Negative effects, such as gradual warming, annual precipitation decrease and frequences of extreme meteorological events have also felt in Hungary. These effects significally tested the adaptive capacity of our cultivated plants. In our country two-thirds of the arable land is occupied by cereals. In most cases there is no crop rotation, pre-crop effect remains unused. Intercrop is a special kind of plant association, where two or more crops growing simultaneously on the same field. It can be increases resilience against pest and pesticides, provides better utilization of growth resources, and weed suppression. In mixture mitigate the effects of climate. Our experiments were made in 2020/2021 with 3 winter wheat varieties (GK Szilárd, Celulle, GK Csillag) and a winter pea variety (Aviron) in 4 repeats, on 10 square meter random layout plots in Szeged-Öthalom. We set 3 different seed density in every variety in every combination. Higher seed density of wheat makes higher yield regardless of pea, except of GK Csillag at 75% seed density of wheat and pea. Increasing pea ratio in mixture, wheat yield decreased. In contrast GK Szilárd and Cellule, their 75% and 100% mixture with 75% Aviron achieved higher wheat yield. Pure stands have shown better values than the combined ones, vice versa for GK Csillag: every seed density with 50% of Aviron gaves the highest wheat yield. Wheat and pea yield together gives the yield advantage what intercrop provides.

Impacts of climate change and human activities on sediment load in Longchuan River Basin, China

Study regionLongchuan River Basin in the Hengduan mountain region, China. Study focusWith the decrease in annual precipitation, the sediment yield on the slope and sediment delivery ratio (SDR) in the river channel, both play a critical role in runoff and sediment load change. However, the response mechanism of SDR to climate change and human activities remains unclear. The RUSLE model was used to calculate the sediment yield on the slope, and the SDR is quantified by the ratio of sediment load in the channel to the sediment yield on the slope.New hydrological insights for the region: Under climate change, the reduced annual rainfall caused a significant decrease in annual runoff and sediment load in the Longchuan River Basin (LRB), since 2003. The RUSLE model was used to calculate the sediment yield on the slope in LRB, and the sediment delivery ratio (SDR) was calculated by the ratio of sediment load to sediment yield. We found a new approach relevant to the relationship of SDR with annual runoff and sediment yield, which can indicate the response mechanism of SDR to climate change. In anthropogenic activities, reservoir interception is the main reason for the sediment load reduction, instead of the land use and land cover change. With a large reservoir built in the LRB, the average SDR is reduced by 83.04 % and the average trap efficiency of the reservoir is 0.96, which was calculated by the Brune equation. This study provides a feasible method to evaluate the effect of different factors on the runoff and sediment load change in the basin.

Unveiling the future of relict Mediterranean mountain peatlands by integrating the potential response of ecological indicators with environmental suitability assessments

Mediterranean mountain peatlands are unique ecosystems because of their distinct hydrology and environmental conditions, as well as being home to a vast array of rare and endemic species. Due to anthropogenic activities and ongoing climate change, mountain peatlands are one of the most endangered ecosystems in Mediterranean areas. Climate scenarios for the western Mediterranean area estimate a sharp decrease in annual precipitation and an upsurge in temperature, which may disrupt the structure and functioning of ground-water-dependent ecosystems. To predict how the environmental suitability of Mediterranean mountain peatlands would be impacted by climate-induced changes, a microscale climatic model was used to downscale 2 m hourly air temperature to a high spatial resolution of 100 m in protected area of North Portugal. The environmental suitability was assessed based on bioclimatic indices associated with mountain peatland indicator species. Climate change projections envisage a decline in the environmental suitability of Mediterranean mountain peatlands and their indicator species, which could compromise this relict ecosystem probability of occurrence. Specifically, environmental suitability was considered highly sensitive to increases in temperature, namely when coupled with decreases in precipitation, resulting in significant reshaping of potential evaporation, evapotranspiration, and soil water content of the areas where peatlands actually occur. Also, the importance of microclimatic information for detecting change in ecosystems that are more vulnerable to climate change and in defining the best management options and conservation priorities is highlighted. Considering their vital role in the conservation of biodiversity and provider of ecosystem services, actions to mitigate and restore Mediterranean mountain peatlands are urgent.

Stable isotopes contain substantial additive information about terrestrial carbon and water cycling

Stable isotope ratios of H (δ 2 H), O (δ 18O), and C (δ 13C) are linked to key biogeochemical processes of the water and carbon cycles; however, the degree to which isotope-associated processes are reflected in macroscale ecosystem flux observations remains unquantified. Here through formal information assessment, new measurements of δ 13C of net ecosystem exchange (NEE) as well as δ 2H and δ 18O of latent heat (LH) fluxes across the United States National Ecological Observation Network (NEON) are used to determine conditions under which isotope measurements are informative of environmental exchanges. We find all three isotopic datasets individually contain comparable amounts of information about NEE and LH fluxes as wind speed observations. Such information from isotope measurements, however, is largely unique. Generally, δ 13C provides more information about LH as aridity increases or mean annual precipitation decreases. δ 2H provides more information about LH as temperatures or mean annual precipitation decreases, and also provides more information about NEE as temperatures decrease. Overall, we show that the stable isotope datasets collected by NEON contribute non-trivial amounts of new information about bulk environmental fluxes useful for interpreting biogeochemical and ecohydrological processes at landscape scales. However, the utility of this new information varies with environmental conditions at continental scales. This study provides an approach for quantifying the value adding non-traditional sensing approaches to environmental monitoring sites and the patterns identified here are expected to aid in modeling and data interpretation efforts focused on constraining carbon and water cycles’ mechanisms.

Long-Term Monitoring of Tree Population Dynamics in Desert Ecosystems: Integrating Field and Satellite Data

Arid environments are characterized by rare rain events that are highly variable, as a result of which plant populations often exhibit episodic recruitment and mortality dynamics. However, direct records and observations of such events are rare because of the slow development of woody species. In this study, we described how a decrease in annual precipitation affected acacia tree population dynamics in two hydrological regime types: small wadis and salt flats. This study combines 15 years of continuous, yearly field monitoring of individual acacia trees and data from a historical Corona satellite image, which has extended the time scope of the research. Results indicate that the annual mortality of acacia trees in small wadis reflects the cumulative effective rain events in the preceding five years, whereas the population on the salt flats was not affected by annual rainfall fluctuations. Moreover, in small wadis, rain events of less than 8 mm did not increase acacia tree survival rates. The mortality pattern and dynamics of each plot was unique, suggesting unsynchronized mortality and recruitment episodes on a regional scale. Mortality in all plots was documented both in “old” trees (i.e., recognized in 1968) and “new” trees (not recognized in 1968), but varied highly between plots. More than 50% of the dead trees recorded at the sites had died during the previous dry period (2000–2010). Combining field monitoring and historical satellite image data provided a unique database of acacia population dynamics. This record revealed the response of the acacia population to climate fluctuations and a period of episodic mortality.