scholarly journals Nitrogen addition pulse has minimal effect in big sagebrush (Artemisia tridentata) communities on the Pinedale Anticline, Wyoming (USA)

2018 ◽  
Author(s):  
Christopher W. Beltz ◽  
Megan L. Mobley ◽  
Ingrid C. Burke
Keyword(s):  
Artemisia Tridentata ◽  
Forage Quality ◽  
Single Pulse ◽  
Nitrogen Addition ◽  
Arid Ecosystems ◽  
Available Nitrogen ◽  
Big Sagebrush ◽  
The Impact ◽  
Nitrogen Additions ◽  
Semi Arid

ABSTRACTNitrogen additions are known to elicit variable responses in semi-arid ecosystems, with responses increasing with precipitation. The response of semi-arid ecosystems to nitrogen are important to understand due to their large spatial extent worldwide and the global trend of increasingly available nitrogen. In this study, we evaluated the impact of a single nitrogen addition pulse on a semi-arid big sagebrush (Artemisia tridentata) ecosystem in western Wyoming. This is important given that sagebrush ecosystems are poorly understood, despite their prevalence in the western US. In addition, large-scale nitrogen additions have begun on sagebrush landscapes in Wyoming in order to mitigate population declines in mule deer (Odocoileus hemionus). The study objectives were (1) to evaluate the effectiveness of a nitrogen fertilization pulse in increasing sagebrush biomass and forage quality, and (2) to assess effects of nitrogen addition on soil biogeochemistry and vegetation community structure. We fertilized 15 plots across 5 locations in western Wyoming using a single pulse of urea (5.5g N m−2). In addition, we immobilized available nitrogen through surface hay treatments (250g hay/m2). Nitrogen additions failed to increase growth of sagebrush, alter nitrogen content of sagebrush leaders, or alter greenhouse gas efflux from soils. The plant community also remained unchanged; total cover, species richness, and community composition were all unaffected by our treatment application. Over the two years of this study, we did not find indications of nitrogen limitation of ecosystem processes, despite a wet growing season in 2014. Thus, we have found a general lack of response to nitrogen in sagebrush ecosystems and no treatment effect of a single pulse of N to sagebrush biomass or forage quality.

scholarly journals Desertification Control Practices in China

2020 ◽  
Vol 12 (8) ◽  
pp. 3258
Author(s):  
Yanli Lyu ◽  
Peijun Shi ◽  
Guoyi Han ◽  
Lianyou Liu ◽  
Lanlan Guo ◽  
...  
Keyword(s):  
Water Conservation ◽  
Anthropogenic Activities ◽  
Northern China ◽  
Global Scale ◽  
Lessons Learned ◽  
Dust Storms ◽  
Arid Ecosystems ◽  
Desertification Control ◽  
The Impact ◽  
Semi Arid

Desertification is a form of land degradation principally in semi-arid and arid areas influenced by climatic and human factors. As a country plagued by extensive sandy desertification and frequent sandstorms and dust storms, China has been trying to find ways to achieve the sustainable management of desertified lands. This paper reviewed the impact of climate change and anthropogenic activities on desertified areas, and the effort, outcome, and lessons learned from desertification control in China. Although drying and warming trends and growing population pressures exist in those areas, the expanding trend of desertified land achieved an overall reversal. In the past six decades, many efforts, including government policies, forestry, and desertification control programs, combined with eco-industrialization development, have been integrated to control the desertification in northern China. Positive human intervention including afforestation, and the rehabilitation of mobile sandy land, and water conservation have facilitated the return of arid and semi-arid ecosystems to a more balanced state. China’s practices in desertification control could provide valuable knowledge for sustainable desertified land management on a global scale.

scholarly journals Effect of Fires on Certain Properties of Forest Soils in Western Algeria

2020 ◽  
Vol 23 (3) ◽  
pp. 111-117
Author(s):  
Ayoub Allam ◽  
Amine Habib Borsali ◽  
Abdelkrim Kefifa ◽  
Mohamed Zouidi ◽  
Raphael Gros
Keyword(s):  
Forest Soils ◽  
Forest Fires ◽  
Arid Zone ◽  
Chemical Properties ◽  
Biological Properties ◽  
Basal Respiration ◽  
Arid Ecosystems ◽  
Control Zone ◽  
The Impact ◽  
Semi Arid

AbstractNatural disturbances, such as forest fires, cause significant changes in the structure and functioning of semi-arid ecosystems. After such disturbances, the impact on the soil ecosystem in its entirety is misunderstood. In this study, two years after the last fire, changes in the physicochemical and biological properties of Aleppo pine forest soils in the semi-arid zone were observed. Among all physical properties analysed, only the soil moisture remained significantly lower in the burnt zone in contrast to control zone. Considering the chemical properties, the only negatively affected parameter is the rate of organic matter. In terms of biological properties, results showed that the fire caused a significant decrease in soil microorganisms by decreasing basal respiration and microbial biomass. Conversely, the metabolic quotient recorded higher values in the fire zone than in the control zone. These results indicate that microbial communities in semi-arid soils, already stressed by climatic hazards, are very sensitive to the passage of even low-intensity fires.

scholarly journals Drought and heatwave impacts on semi-arid ecosystems' carbon fluxes along a precipitation gradient

2020 ◽  
Vol 375 (1810) ◽  
pp. 20190519 ◽  
Author(s):  
Tarek S. El-Madany ◽  
Arnaud Carrara ◽  
M. Pilar Martín ◽  
Gerardo Moreno ◽  
Olaf Kolle ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Ecosystem Respiration ◽  
Carbon Fluxes ◽  
Arid Ecosystems ◽  
Severe Drought ◽  
Precipitation Gradient ◽  
Continental Scale ◽  
Compound Event ◽  
The Impact ◽  
Semi Arid

The inter-annual variability (IAV) of the terrestrial carbon cycle is tightly linked to the variability of semi-arid ecosystems. Thus, it is of utmost importance to understand what the main meteorological drivers for the IAV of such ecosystems are, and how they respond to extreme events such as droughts and heatwaves. To shed light onto these questions, we analyse the IAV of carbon fluxes, its relation with meteorological variables, and the impact of compound drought and heatwave on the carbon cycle of two similar ecosystems, along a precipitation gradient. A four-year long dataset from 2016 to 2019 was used for the FLUXNET sites ES-LMa and ES-Abr, located in central (39°56'25″ N 5°46'28″ W) and southeastern (38°42'6″ N 6°47'9″ W) Spain. We analyse the physiological impact of compound drought and heatwave on the dominant tree species, Quercus ilex. Our results show that the gross primary productivity of the wetter ecosystem was less sensitive to changes in soil water content, compared to the dryer site. Still, the wetter ecosystem was a source of CO 2 each year, owing to large ecosystem respiration during summer; while the dry site turned into a CO 2 sink during wet years. Overall, the impact of the summertime compound event on annual CO 2 fluxes was marginal at both sites, compared to drought events during spring or autumn. This highlights that drought timing is crucial to determine the annual carbon fluxes in these semi-arid ecosystems. This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.

scholarly journals Nitrogen addition pulse has minimal effect in big sagebrush (Artemisia tridentata) communities on the Pinedale Anticline, Wyoming (USA)

PLoS ONE ◽  
2019 ◽  
Vol 14 (5) ◽  
pp. e0206563
Author(s):  
Christopher W. Beltz ◽  
Megan L. Mobley ◽  
Ingrid C. Burke
Keyword(s):  
Artemisia Tridentata ◽  
Nitrogen Addition ◽  
Minimal Effect ◽  
Big Sagebrush

Kalahari Cheetahs

2017 ◽  
Author(s):  
Gus Mills ◽  
Margaret Mills
Keyword(s):  
Reproductive Success ◽  
Spatial Ecology ◽  
Prey Selection ◽  
Arid Ecosystems ◽  
Foraging Success ◽  
Ecological Processes ◽  
Demographic Groups ◽  
Important Prey ◽  
Hunting Behaviour ◽  
The Impact

This book demonstrates how cheetahs are adapted to arid savannahs like the southern Kalahari, and makes comparisons with other areas, especially the Serengeti. Topics dealt with are: demography and genetic status; feeding ecology, i.e. methods used for studying diet, diets of different demographic groups, individual diet specializations of females, prey selection, the impact of cheetah predation on prey populations, activity regimes and distances travelled per day, hunting behaviour, foraging success and energetics; interspecific competition; spatial ecology; reproductive success and the mating system; and conservation. The major findings show that cheetahs are well adapted to arid ecosystems and are water independent. Cheetah density in the study area was stable at 0.7/100 km2 and the population was genetically diverse. Important prey were steenbok and springbok for females with cubs, gemsbok, and adult ostrich for coalition males, and steenbok, springhares, and hares for single animals. Cheetahs had a density-dependent regulatory effect on steenbok and springbok populations. Females with large cubs had the highest overall food intake. Cheetahs, especially males, were often active at night, and competition with other large carnivores, both by exploitation and interference, was slight. Although predation on small cubs was severe, cub survival to adolescence was six times higher than in the Serengeti. There was no difference in reproductive success between single and coalition males. The conservation priority for cheetahs should be to maintain protected areas over a spectrum of landscapes to allow ecological processes, of which the cheetah is an integral part, to proceed unhindered.

scholarly journals Direct effects of nitrogen addition on seed germination of eight semi‐arid grassland species

2020 ◽  
Vol 10 (16) ◽  
pp. 8793-8800
Author(s):  
Tong Zhang ◽  
Mengzhou Liu ◽  
Xudong Huang ◽  
Wei Hu ◽  
Ning Qiao ◽  
...  
Keyword(s):  
Seed Germination ◽  
Nitrogen Addition ◽  
Direct Effects ◽  
Grassland Species ◽  
Semi Arid

scholarly journals The Dessau Grassland Experiment—Impact of Fertilization on Forage Quality and Species Assembly in a Species-Rich Alluvial Meadow

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 339
Author(s):  
Sandra Dullau ◽  
Knut Rydgren ◽  
Anita Kirmer ◽  
Urs Georg Jäger ◽  
Maren Helen Meyer ◽  
...  
Keyword(s):  
Nitrogen Fertilization ◽  
Conservation Status ◽  
Forage Quality ◽  
Habitats Directive ◽  
Long Term Experiment ◽  
Phosphorus And Potassium ◽  
Eu Habitats Directive ◽  
Summer Flood ◽  
The Impact ◽  
Species Assembly

Since alluvial meadows of river valleys of the Cnidion dubii are protected by the EU Habitats Directive, reconciling farmers’ demands for forage quality with the objective of maintaining them in good conservation status is an important issue in grassland research. In a long-term experiment from 2010 to 2018, we investigated the impact of fertilizing on forage quality and species assembly on a species-rich and twice-mown alluvial grassland in the Dessau Elbe floodplain (Germany). The experiment was composed of an unfertilized control, PK, N60, N60PK and N120PK applications. A significant improvement in forage quality was achieved by nitrogen fertilization only for crude protein, with higher feeding requirements for sheep met only in individual years. The legume cycle was inhibited by the application of nitrogen and high grass cover was maintained, but not increased, at the highest nitrogen application after an exceptional summer flood. The target forbs persisted in numbers over the study period in all treatments. For cover, the low-competitive target forbs responded neutrally to nitrogen fertilization, whereas detrimental effects were demonstrated for the competitive ones. Thus, we recommend not applying more than 60 kg year−1 of nitrogen and only in combination with phosphorus and potassium.

scholarly journals Effect of Organic Amendment Addition on Soil Properties, Greenhouse Gas Emissions and Grape Yield in Semi-Arid Vineyard Agroecosystems

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1477
Author(s):  
Antonio Marín-Martínez ◽  
Alberto Sanz-Cobeña ◽  
Mª Angeles Bustamante ◽  
Enrique Agulló ◽  
Concepción Paredes
Keyword(s):  
Soil Fertility ◽  
Soil Properties ◽  
Greenhouse Gas ◽  
Co2 Emissions ◽  
Organic Amendments ◽  
Organic N ◽  
N2o Emissions ◽  
The Impact ◽  
Semi Arid ◽  
Grape Yield

In semi-arid vineyard agroecosystems, highly vulnerable in the context of climate change, the soil organic matter (OM) content is crucial to the improvement of soil fertility and grape productivity. The impact of OM, from compost and animal manure, on soil properties (e.g., pH, oxidisable organic C, organic N, NH4+-N and NO3−-N), grape yield and direct greenhouse gas (GHG) emission in vineyards was assessed. For this purpose, two wine grape varieties were chosen and managed differently: with a rain-fed non-trellising vineyard of Monastrell, a drip-irrigated trellising vineyard of Monastrell and a drip-irrigated trellising vineyard of Cabernet Sauvignon. The studied fertiliser treatments were without organic amendments (C), sheep/goat manure (SGM) and distillery organic waste compost (DC). The SGM and DC treatments were applied at a rate of 4600 kg ha−1 (fresh weight, FW) and 5000 kg ha−1 FW, respectively. The use of organic amendments improved soil fertility and grape yield, especially in the drip-irrigated trellising vineyards. Increased CO2 emissions were coincident with higher grape yields and manure application (maximum CO2 emissions = 1518 mg C-CO2 m−2 d−1). In contrast, N2O emissions, mainly produced through nitrification, were decreased in the plots showing higher grape production (minimum N2O emissions = −0.090 mg N2O-N m−2 d−1). In all plots, the CH4 fluxes were negative during most of the experiment (−1.073−0.403 mg CH4-C m−2 d−1), indicating that these ecosystems can represent a significant sink for atmospheric CH4. According to our results, the optimal vineyard management, considering soil properties, yield and GHG mitigation together, was the use of compost in a drip-irrigated trellising vineyard with the grape variety Monastrell.

Noteworthy records and updated richness of medium to large-sized mammals in arid and semi-arid ecosystems of northern Peru and southern Ecuador

2021 ◽  
Vol 188 ◽  
pp. 104471
Author(s):  
Alvaro García-Olaechea ◽  
Zoila Vega ◽  
Cindy M. Hurtado
Keyword(s):  
Arid Ecosystems ◽  
Southern Ecuador ◽  
Northern Peru ◽  
Semi Arid
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