Rainfall pulses can therefore significantly influence the structure and function of desert ecosystems , and analysis of the responses of ANPP to these pulses is critical to understanding the response mechanisms that contribute to the sustainability of desert ecosystems. 5a ). (A) From April to October in 2007; (B) From April to October in 2011; (C) From April to October between 2004 and 2012. https://doi.org/10.1371/journal.pone.0073003.g003. regulation and distribution tendency of plants and their response mechanism to rainfall. Furthermore, the CO2 uptake of shrubs in response to precipitation events with multiple peaks in a growing season when rainfall distribution is suitable , is a trait consistent with the multi-peak model in ANPP. Furthermore, for the shrubs Nitraria sphaerocarpa and Elaeagnus angustifolia in a desert ecosystem, the lower stem rainfall thresholds were 5 mm for the sap flow response , an indicator of the potential for shrub growth and water use patterns, whereas in a temperate Australian woodland, the threshold needed for rain events to elicit an increase of sap flow exceeded 20 mm . Moreover, winter or early spring precipitation establishes deeper soil moisture content at the onset of the growing season and frequently represents a peak in the entire growing season ANPP dynamics, favoring shrubs . Ecosystem responses to the rainfall regime have included altered ANPP –, gas exchange , –, and ecosystem respiration –. The spatial distribution of grass patches showed a certain predictability, thus providing baseline data for range management. Similarly, the NDVIs of the after response were selected as the maximum response variable value. Yes This result also indicates that the time of precipitation is important to NDVI, because of the physiological state of shrubs. net primary production. The parameter ymax reflects differences in physiology and growth strategies . Wrote the paper: FL WZ HL. This research focused on understanding how a desert ecosystem responds to changes in precipitation regimes. The seasonal production of dry matter was related directly to the seasonal precipitation in the arfaj steppe, whereas the remeth steppe did not show an obvious relationship to the precipitation. MODIS Terra and Aqua surface reflectance 8-day composited (which reduces the influence of weather conditions and clouds) collection 5 level 3 global at 250 m spatial resolution (MOD09Q1 and MYD09Q1) in HDF format, were acquired between 2005 and 2012 in the growing season, from the following website: http://ladsweb.nascom.nasa.gov/data/search.html which is maintained by the NASA Land Processes Distributed Active Archive Center at the USGS. biome. Due to differences in soil physical and mineralogical properties, and to biodiversity structure and the root systems' abilities to exploit moisture, dune and desert areas differed in precipitation responses: dune habitats were characterized by a single, late summer productivity peak; in contrast, deserts showed a multi-peak pattern throughout the growing season. NDVI responses were different in the early and middle growing seasons (Figure 5) in 2011. Noy-Meir's summary of annual above-ground net primary production suggests production varies from 30 to 300 g dry wt . ʅ Switch between this layer and the vegetation layer (September 2015). All of these characteristics exhibited the rainfall pulse patterns of an arid region. Many biological state changes where organisms transition from a lower to a higher state of physiological activity, require a minimal triggering event size . The arctic tundra has a net primary productivity of 600 kcal per square metre, per year. Method: To quantify the utilization of rains with different pulse intensities by H. songaricum and Sarcozygium xanthoxylum, we established and analyzed relationships between plant xylem water of H. songaricum and S. xanthoxylum and potential water (precipitation, soil water and ground water) within 9 days following each natural rain eventusing hydrogen stable isotopes. and 2) could rainfall pulse cause multiple productivity peaks in the desert and dune ecosystems during the growing season? Rainfall events can be characterized as “pulses”, which are discrete and variable episodes that can significantly influence the structure and function of desert ecosystems, including shifts in aboveground net primary productivity (ANPP). Meanwhile, in grass (shrub) communities, spring and summer precipitation thresholds for CO2 uptake were 23(59) mm and 51–148(57–140) mm, respectively, and the spring response had an impact on the summer threshold values . Chew RM, Chew AE (1965) The primary productivity of a desert shrub (Larrea tridentata) community. broad scope, and wide readership – a perfect fit for your research every time. In response to lower amounts: the NDVI in the desert and dune ecosystems responded significantly at 6.4 mm of effective rainfall on 22 July 2011, but the increases here were much smaller – 0.4% and 1.46% respectively. An average seasonal precipitation of 90 mm supported a mean of 223 kg ha ⁻¹ in arfaj steppe in 1979–1989, whereas an average mean seasonal precipitation of 73 mm during 1983–1989 maintained a mean phytomass of 102 kg ha ⁻¹ in the remeth steppe. The observations used for these analyses come from both the Terra and Aqua satellites. https://doi.org/10.1371/journal.pone.0073003.g004. This rainfall threshold represents an ecologically significant rainfall event that interacts with a plant's water-use patterns of utilizing soil moisture pulses at particular infiltration depths or durations , . (B) The mean NDVI of the dune study area response to rainfall pulses for Terra and Aqua satellites. The magnitude of the increase in the response (δt) and the potential response (δt*) values of desert (dune) were 0.0065 (0.0161) and 0.0139 (0.0250), respectively, indicating that the dune response values were significantly greater than desert after the same precipitation pulses. Der Begriff Primärproduktion bezeichnet in der Ökologie die Produktion von Biomasse durch die Produzenten, also Pflanzen, Algen, Cyanobakterien und andere autotrophe Bakterien, mithilfe von Licht oder chemischer Energie aus anorganischen Substanzen. The Response of Aboveground Net Primary Productivity of Desert Vegetation to Rainfall Pulse in the Temperate Desert Region of Northwest. Emphasis is placed on aboveground net primary production (ANPP), a major component of energy that drives ecosystem processes, and on potential evapotranspiration (PET), the abiotic variable most often used to explain variation in ANPP. By Li Fang, Zhao Wenzhi and Liu Hu. A variety of models of primary productivity response to rainfall variability-the two-layer hypothesis , the pulse-reserve hypothesis , and the threshold-delay model -continue to be used with various theoretical (and subsequently operational) modifications in order to generate different scales of plant response. 5–10 mm: n = 20; others: n = 12. Increases in productivity depend on nutrient distribution and the presence of moisture, which … Furthermore, NPP loss variation in different grassland types under the same drought level was significantly different. As was hypothesized, the use of an NDVI dataset extracted from a MODIS image dataset with 8-day temporal resolution and 250 m spatial resolution revealed the rainfall-productivity relationship at the ecosystem scale, but the relationships differed in the temporal scale. Some of the important conclusions about ANPP have been: Lauenroth et al. This difference is likely related to life forms and functional groups, and responses to abiotic drivers  to which sub-shrub and small shrub species in the desert are sensitive, whereas shrub species in the dune ecosystem evidently are not. They have hostile living conditions for plants and animals so net primary productivity is quite low. Also, the soil water potential was higher in desert habitat. groups of terrestrial ecosystems that share biotic and abiotic conditions. Ecosystems clearly have a “memory” of past precipitation events which can last at least several decades . DESERTS: While Antarctica is a cold desert, hot deserts are covered in sand with little rainfall. When the rainfall event size was less than 30 mm, the increments of NDVI were about 0.01 and 0.005 of increase, for dune and desert respectively, but the increments reached 0.04 and 0.02 with greater than 30 mm of rainfall. No, Is the Subject Area "Shrubs" applicable to this article? (A) The mean NDVI of the desert study area response to rainfall pulses for Terra and Aqua satellites. climatograph. The threshold-delay model is an integrative framework for plant growth delays, precipitation thresholds, and plant FT strategies, which captures the nonlinear nature of plant responses to rainfall pulses. The Response of Aboveground Net Primary Productivity of Desert Vegetation to Rainfall Pulse in the Temperate Desert Region of Northwest China Li, Fang Zhao, Wenzhi This study provides baseline data for nitrogen amendments on soil microbial status, as well as insights into the importance of nitrogen in fertility in arid environments. Within morphologically similar species, it was determined by the variation in tolerance to soil water potential . Understanding responses to variation in rainfall event size and frequency will assist in assessing how desert ecosystems may change under future scenarios of more extreme precipitation regimes. The accumulative rainfall from June to August in 2007 and 2011 were identical 83.5 mm. We determined the rainfall threshold by means of linear regression model, and the parameters of the threshold-delay model by means of multiple linear regression (Table 5). Trophical rainforests have an average net primary productivity(NPP) of 1, 5 0 0 g / m 2 / y r. Open oceans and deserts have average NPP of 1 2 5 and 9 0 g / m 2 / y r respectively. RU is the upper threshold above which rain events than do not yield additional benefits; and (C) provides a hypothetical response curve. Although we did not detect a significant correlation between the duration of the dry interval and the two habitats' NDVIs, the variability of duration of the dry interval could weaken the response of soil moisture to a rainfall event , and soil moisture is a key parameter in the rainfall-productivity relationship. Aerosol Optical Depth Aerosol Size Carbon Monoxide Chlorophyll Cloud Fraction Fire Land Surface Temperature Land Surface Temperature Anomaly Net Primary Productivity Net Radiation Sea Surface Temperature Sea Surface Temperature Anomaly Snow Cover Total Rainfall Vegetation Water Vapor Show Related Maps. https://doi.org/10.1371/journal.pone.0073003.g002. In both habitats, when the rainfall was less than 43.7 mm, the NDVI was monotonically increasing and the maximum rainfall threshold was not reached. https://doi.org/10.1371/journal.pone.0073003.g007. 4) In the intermediate rain event, the competition between H. songaricum and S. xanthoxylum for the soil water was obvious. When NDVI increment was equal to zero, the corresponding rainfall size was determined as the lower precipitation threshold. Based on net primary productivity (NPP) and the transpiration coefficient, a vegetation water consumption model was developed to estimate the water consumption in desert oasis in ERDAS environment. The rainfall event size categories were divided into five types, 5–10 mm, 10–15 mm, 15–20 mm, 20–30 mm, and greater than 30 mm, according the number and distribution of 17 precipitation event sizes. Department of Biology MSC03‐2020, University of New Mexico, Albuquerque, New Mexico 87131, USA … Topic 1.8: Primary Productivity Gross primary productivity is the total rate of photosynthesis in a given area Net primary productivity is the rate of energy storage by photo synthesizers in a given area, after subtracting the energy lost to respiration. Furthermore, when the rainfall event size was more than 30 mm, NDVI rapidly increased 3- to 6-fold compared with the response to events of less than 30 mm, suggesting that 30 mm was the threshold for a large NDVI response. Carbon uptake and change in net primary productivity of oasis-desert ecosystem in arid western China with remote sensing technique. yr- in arid zones. In addition, the error terms in this paper represent the standard errors of the all the pixels in the study area. At the event on 25 June 2011, the dune ecosystem had no apparent increase of NDVI, but the desert did. The rainfall event size categories × habitats interaction was significant. Compared to previous research in grassland, this value is much higher than the one for a short-grass steppe, in which precipitation events of 15 mm to 30 mm contributed most of the effect of precipitation on ANPP . Our results demonstrated that the ecosystem in the middle reaches of the Heihe oasis consumed water of 18.41×10 8 –21.9×10 8 m 3 for irrigation. Result: 1) We found that the soil moisture increased and soil water δ Ddecreased in the surface soil of 0-20 cm after 8.6 mm within 9 days, and the soil moisture and soil water δ Dchanged obviously in the soil of 0-40 cm after 12.1 mm within 9 days, whereas the soil moisture and soil water δ Dchanged significantly in all soil depth after 79.6 mm with in 9 days. primary productivity- primary productivity is the rate at which producers (plants) convert energy from the sun into chemical energy; desert plants lack an efficient amount of photosynthesis, therefore less carbon dioxide is produced. They have hostile living conditions for plants and animals so net primary productivity is quite low. PLoS ONE 8(9): The frequency of all the different rainfall classes was similar, between 14% and 20%; the differences were reduced among the rainfall classes. New woody tissues in trunk and branches accounted for 51.5% of the allocation of productivity in Prosopis, a remarkably high woody allocation for a desert plant. This chapter provides a detailed overview on productivity of deserts. The values of k were different for desert and dune habitats, 0.9564 and 0.9547, respectively, indicating that the duration of desert habitat response to a precipitation pulse is greater than that for dune habitat. Yes Net primary productivity is dependent on various factors such as temperature, nutrient availability, humidity, sunlight, etc. Our results showed that a precipitation event size of more than 5 mm does have a pronounced effect on the NDVI of the desert ecosystem independent of precipitation amount (p<0.001) (Table 3). 03). Seventeen precipitation events were selected (Table 2). What percent of the sunlight is actually converted into chemical energy via photosynthesis? The nitrate proportion of the total soluble nitrogen in the soil also increased with the increase in soil moisture. We thank Marian Rhys for language assistance. This difference was most likely the result of higher demand for water in the desert ecosystem, caused by lower holding capacities and hydraulic conductivity, higher evaporation rates, and different soil moisture dynamics . This makes it hard for plants and vegetation to grow, thus, producing less organic substances compared to other biomes. The curves revealed that the increments in NDVI could be expressed as a linear function of rainfall event size. Click through the PLOS taxonomy to find articles in your field. To determine the threshold and hierarchical response of rainfall event size on the Normalized Difference Vegetation Index (NDVI, a proxy for ANPP) and the difference across a desert area in northwestern China with two habitats – dune and desert – we selected 17 independent summer rainfall events from 2005 to 2012, and obtained a corresponding NDVI dataset extracted from MODIS images. The highest utilization rate of rain water by H. songaricum within 9 days was 67.0% under the small rain event (<10 mm) and 71.8% under the intermediate event. desert. Year: 2013. Most of the rainfall events were small, with the majority (67%) being less than 5 mm. The relationships show significant linear trends for dune and desert ecosystems. https://doi.org/10.1371/journal.pone.0073003.t003. To determine the effect of precipitation pulses on an arid desert ecosystem, we selected 17 independent precipitation events during the summer from 2005 to 2012 in the middle reach of the Heihe River, and evaluated desert and dune ecosystems responses using the threshold-delay model and statistical analysis. However, the potential evaporation is 2390 mm/y, which is 20 times the precipitation. Linze Inland River Basin Research Station, Key Laboratory of Inland River Basin Ecohydrology, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China. Letters above columns represent significantly different treatments (Tukey's HSD test, P<0.05). Hence it can be concluded that a rainfall event of 5 mm is an ecologically significant rainfall event for ANPP responses in desert ecosystems. The entire desert ecosystem NDVI growth rate was 3%–9% when rainfall was less than 30 mm, but it reached 22.5% with more than 30 mm – a 3- to 6-fold increase. The climate is arid to semiarid temperate continental desert. In addition, adequate precipitation during the previous winter and spring may supply moisture to the deeper roots of shrubs, allowing them to aggressively exploit water availability with their physiologically active state during the early growing season . Mean annual temperature is 7.6°C with an average low of –27.3°C in January and a high of 39.1°C in July.  discovered that the best response to individual precipitation event size of ANPP for short grass prairie was 15–30 mm. present in an ecosystem; NPP is highest in tropical forests and lowest in deserts; Around 1% of the total solar energy reaching the earth per unit area and time gets stored in the form of biomass; Gross Primary Productivity and Net Primary Productivity . Error bars represent standard error for all the pixels in the study area. However, the maximum rainfall event size for the desert ecosystems was not determined and needs further research. The images were treated with projection transformation and image registration and were clipped using a study area border executed in ENVI 4.7 Software. We analyzed the significance in response of NDVI to rainfall pulses using a three-factor ANOVA to compare both the main effects and the interactive effects of rainfall event size categories, habitats (desert vs. dune), and before and after responses, using SPSS software, version 18. 5) The root of H. songaricum was mainly distributed in soil layers of 0-40 cm, its fine roots are mostly distributed in the layers of 0-20 cm and 20-40 cm, which accounted for 58% and 37% of the total fine root biomass respectively, while the root biomass of S. xanthoxylum was primarily distributed in soil layers of 20-60 cm, its fine roots were mostly distributed in the layers of 20~60 cm (68.2%). Effects of rainfall and grazing on vegetation yield and cover of two arid rangelands in Kuwait. Increments in the NDVI could be a direct response of the ANPP to different rainfall event sizes (Figure 5). 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