scholarly journals Differential intra-specific stemflow funnelling efficiencies of Caragana korshinskii within arid desert ecosystems

2017 ◽  
Vol 48 (6) ◽  
pp. 1611-1623 ◽  
Author(s):  
Ya-feng Zhang ◽  
Xin-ping Wang ◽  
Rui Hu ◽  
Yan-xia Pan
Keyword(s):  
Northern China ◽  
Desert Ecosystem ◽  
Absolute Amount ◽  
Desert Ecosystems ◽  
Rainfall Events ◽  
Rainfall Condition ◽  
Caragana Korshinskii ◽  
Specific Variation ◽  
Morphological Differences ◽  
Arid Desert

Abstract Stemflow is known as a highly localized point input of rainwater and solutes around tree/shrub bases where roots are concentrated, thus having considerable effects on hydrology and biogeochemistry of vegetated ecosystems. Stemflow shows a pronounced inter-specific variation due to morphological differences among species, while the intra-specific variation of stemflow has been poorly explored. We systematically examined the effects of shrub morphological metrics on intra-specific funnelling efficiencies by quantifying the stemflow of nine shrubs of Caragana korshinskii within a water-limited arid desert ecosystem of northern China. Stemflow volume was used to compare the absolute amount of stemflow generated by shrubs of varying size, and funnelling ratio was used to assess their funnelling efficiencies. Both rainfall depth and shrub morphological metrics significantly affected stemflow volume, while funnelling ratio was more associated with shrub morphology. Under the same rainfall condition, smaller shrubs produced lower volumes of stemflow, while gaining access to rainfall via higher funnelling ratio than larger shrubs. Our findings highlight a large variation in funnelling efficiency among individual shrubs within the same species, and in particular, smaller shrubs might profit more from sporadic small rainfall events than larger shrubs.

scholarly journals Desert shrub stemflow and its significance in soil moisture replenishment

2011 ◽  
Vol 15 (2) ◽  
pp. 561-567 ◽  
Author(s):  
X.-P. Wang ◽  
Z.-N. Wang ◽  
R. Berndtsson ◽  
Y.-F. Zhang ◽  
Y.-X. Pan
Keyword(s):  
Soil Moisture ◽  
Soil Profile ◽  
Root Zone ◽  
Sand Dunes ◽  
Aluminum Foil ◽  
Time Domain Reflectometry ◽  
Desert Ecosystem ◽  
Desert Ecosystems ◽  
Caragana Korshinskii ◽  
Moisture Variation

Abstract. Stemflow of xerophytic shrubs represents a significant component of water replenishment to the soil-root system influencing water utilization of plant roots at the stand scale, especially in water scarce desert ecosystems. In this study, stemflow of Caragana korshinskii was quantified by an aluminum foil collar collection method on re-vegetated sand dunes of the Shapotou restored desert ecosystem in northwestern China. Time domain reflectometry probes were inserted horizontally at 20 different soil profile depths under the C. korshinskii shrub to monitor soil moisture variation at hourly intervals. Results indicated that 2.2 mm precipitation was necessary for the generation of stemflow for C. korshinskii. Stemflow averaged 8% of the gross precipitation and the average funnelling ratio was as high as 90. The soil moisture in the uppermost soil profile was strongly correlated with individual rainfall and the stemflow strengthened this relationship. Therefore, it is favourable for the infiltrated water redistribution in the deeper soil profile of the root zone. Consequently, stemflow contributes significantly to a positive soil moisture balance in the root zone and the replenishment of soil moisture at deeper soil layers. This plays an important role in plant survival and the general ecology of arid desert environments.

scholarly journals A rainfall enrichment system suitable for open field experiments in arid and semi-arid ecosystems

Lilloa ◽  
2020 ◽  
pp. 54-71
Author(s):  
Zhiming Xin ◽  
Jianqiang Qian ◽  
Carlos A. Busso ◽  
Bo Wu ◽  
Yajuan Zhu ◽  
...  
Keyword(s):  
Open Field ◽  
Field Experiments ◽  
Experimental Studies ◽  
Terrestrial Ecosystems ◽  
Arid Ecosystems ◽  
Hydraulic Pressure ◽  
Desert Ecosystems ◽  
Rainfall Events ◽  
Arid Desert ◽  
Semi Arid

The predicted changes in precipitation patterns because of global change have profound effects on terrestrial ecosystems. In the present study, the principle and design details of a rainfall enrichment system (RAINES) for open field experiments in semi-arid and arid ecosystems are shown. The rainfall intensity, validity and uniformity of this experimental facility were also tested. During the period from 2008 to 2010, our data showed that the RAINES was able to simulate rainfall events with different rainfall sizes, frequencies and timing. The greatest advantage of the RAINES was its high uniformity in rainfall distribution over a relatively large experimental surface area (>90 m2), which was important for experimental studies of semi-arid and arid ecosystems where vegetation distribution is sparse. The rainfall validity of RAINES was steadily at 66% or higher as long as the hydraulic pressure exceeded 1.4 KPa and the wind speed was below 2.5 m s-1. Since the RAINES is light-weight, inexpensive and versatile enough to be used to simulate various rainfall events with needed properties in remote fields, it is able to provide reliable simulated rainfall in the field for studying possible responses of soil and vegetation processes to rainfall change in arid and semi-arid ecosystems. The application of the RAINES will improve our understanding on the relationship between water availability and ecosystem processes in arid and semi-arid ecosystems, which will provide useful knowledge for the protection, restoration and sustainable management of semi-arid and arid desert ecosystems world.

scholarly journals Niche Differentiation and Co-Occurrence Network of Fungal Communities Associated with Host Affiliations in an Extremely Arid Desert Ecosystem

2020 ◽  
Author(s):  
Yiling Zuo ◽  
Xia Li ◽  
Jingya Yang ◽  
Jiaqiang Liu ◽  
Xueli He ◽  
...  
Keyword(s):  
Endophytic Fungi ◽  
Sequence Similarity ◽  
Mutual Exclusion ◽  
Keystone Species ◽  
Fungal Communities ◽  
Desert Ecosystem ◽  
Desert Plants ◽  
Desert Ecosystems ◽  
Desert Shrubs ◽  
Arid Desert

Abstract Background: Desert shrubs represent high productivity and play essential roles in maintaining the biodiversity and stability of ecosystem functioning in arid desert ecosystems. These xerophytic plants provide specific biotic and abiotic conditions for the resident specialist microorganisms. However, a robust understanding of the structural composition of the fungal microbiome associated with desert plants and especially the relationship between above- and belowground communities is currently lacking. In this study, we examined the endophytic fungal communities associated with the root, stem, and leaf tissues of five desert shrubs using Illumina MiSeq sequencing of internal transcribed spacer 2 (ITS2) sequences.Results: A total of 337 operational taxonomic units (OTUs) of endophytic fungi were identified at a 97% sequence similarity level. Pleosporales were dominant and played an irreplaceable role as keystone species in maintaining the connectivity and complexity of the fungal networks. Desert shrub identity significantly affected the community composition of the endophytic fungi in different tissues. Compared with the fungi in the aboveground tissues, root-associated fungi represented the most abundant reservoir of biodiversity in the desert habitat and displayed significantly high tissue specificity. Interestingly, the aboveground stems and leaves showed higher taxonomic overlap with underground root tissues than with each other. The root fungal network revealed the highest connectivity, and the interspecies relationships between desert fungal OTUs revealed a high percentage of co-presence rather than mutual exclusion. In addition, members of Hypocreales played a central role in connecting the above- and belowground fungal networks.Conclusions: This study represents the first example of research revealing plant-fungus endophytic associations in an extremely arid desert ecosystem with the simultaneous consideration and comparison of above- and belowground niches. Understanding the complex host-microbe interactions associated with desert plants could provide a basis for the exploitation of plant-fungus associations in the manipulation of the shrub microbiome for ecological restoration purposes.

scholarly journals Stemflow of desert shrub and its significance in soil moisture replenishment

2010 ◽  
Vol 7 (4) ◽  
pp. 5213-5234
Author(s):  
X.-P. Wang ◽  
Z.-N. Wang ◽  
R. Berndtsson ◽  
Y.-F. Zhang ◽  
Y.-X. Pan
Keyword(s):  
Soil Moisture ◽  
Soil Profile ◽  
Root Zone ◽  
Sand Dunes ◽  
Aluminum Foil ◽  
Time Domain Reflectometry ◽  
Desert Ecosystem ◽  
Desert Ecosystems ◽  
Caragana Korshinskii ◽  
Moisture Variation

Abstract. Stemflow of xerophytic shrubs represents a significant component of water replenishment to the soil-root systems influences water utilization of plant roots at the stand scale, especially for water scarce desert ecosystems. In this study, stemflow of Caragana korshinskii was quantified by aluminum foil collar collection method at re-vegetated sand dunes of the Shapotou restored desert ecosystem in Northwestern China. Meanwhile, time domain reflectometry probes were inserted horizontally at 20 different soil profile depths under the C. korshinskii shrub to monitor soil moisture variation at hourly intervals. Results indicated that 2.2 mm precipitation were necessary for the generation of stemflow for C. korshinskii. Stemflow averaged 8% of the gross precipitation, and the average funneling ratio was as high as 90. The soil moisture in the uppermost soil profile was strongly correlated with individual rainfall and the stemflow strengthened this relationship. Therefore, it is favorable for infiltrated water redistribution in the deeper soil profile of the root zone. We conclude that stemflow contributes significantly to a positive soil moisture balance in the root zone and the replenishment of soil moisture at deeper soil layers. This plays an important role in plant survival and the general ecology of arid desert environments.

Ecophysiological Responses of desert shrub to rainfall addition for Reaumurica soongorica in desert ecosystem

2020 ◽  
Author(s):  
Wei Li ◽  
Cicheng Zhang
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Vapour Pressure Deficit ◽  
Desert Ecosystem ◽  
Heihe River ◽  
Desert Ecosystems ◽  
Rainfall Events ◽  
Ecophysiological Responses ◽  
Predominant Factor

<p>Desert environments are characterized by limited and highly variable rainfall, which is an intermittent source of water critical to the evolution of the structure and functioning of desert ecosystems. The present study was to assess the effects of different amounts of rainfall received through discrete rainfall events and of the ecophysiological responses for Reaumurica soongorica along multiple average precipitation (MAP) gradient. A field experiment was performed under seven simulated rainfall amounts (0 - 40 mm) with Reaumurica soongorica at respective High-P (120 mm), Middle-P (67 mm), and Low-P (35 mm) sites along middle and lower reach of Heihe River Basin in July, 2015. Pre-dawn plant water potential (ψ<sub>pd</sub>), the rates of photosynthesis and stomatal conductance were measured synchronously. Results showed that: photosynthetic response of R.soongorica to rainfall pulse was significant different. The mean daily leaf gas exchange and maximum photosynthesis rate (P<sub>n-max</sub>) of R.soongorica were decreased obviously with decreasing MAP. Vapour pressure deficit (VPD) was the predominant factor for gas exchange limiting. Under the control of VPD, stomatal conductance was pregressively reduced with decreasing ψ<sub>pd</sub>, which was functioned as limiting P<sub>n-max</sub> and further increasing water use efficiency (WUE). However, when MAP was declined below 35 mm, the response of stomatal conductance to ψ<sub>pd</sub> was weakened, from which P<sub>n-max</sub> began to increase again. 2 to 4 days hystereric response of R.soongorica ψ<sub>pd</sub> to various rainfall events was found in High-P. Stomatal conductance was then increased linearly with increasing ψ<sub>pd</sub>, from which P<sub>n-max </sub>was also enhanced linearly. While weakly response of ψ<sub>pd</sub> to similar rainfall events was observed in Low-P, where stomatal conductance and P<sub>n-max</sub> was maintained stable after rain. Mentioned above, the effective rainfall pluse, induced by obvious physiological response of R. soongorica, was 3.63-6.73 mm and 6.73-10.09 mm for Linze and Ejina, respective. Our results provided comprehensively understanding in the consequences of long-term variability in rainfall for the physiology of desert plants and species dynamics in desert ecosystems.</p>

scholarly journals Rainfall in growing season determines the size of an annual-dominated soil seed bank in a desert ecosystem

2020 ◽  
Author(s):  
Ya-Fei Shi ◽  
Zengru Wang ◽  
Bing-Xin Xu ◽  
Jian-Qiang Huo ◽  
Rui Hu ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Growing Season ◽  
Seed Banks ◽  
Desert Ecosystem ◽  
Perennial Herb ◽  
Desert Ecosystems ◽  
Soil Seed Banks

Soil seed banks may offer great potential for restoring and maintaining desert ecosystems that have been degraded by climate change and anthropogenic disturbance. However, few studies have explored the annual dynamics in the composition and relative abundance of these soil seed banks. We conducted a long-term observational study to assess the effects of environmental factors (meteorology and microtopography) and aboveground vegetation on the soil seed bank of the Tengger Desert, China. The desert seed bank was dominated by annual herbs. We found that more rainfall in the growing season increased the number of seeds in the soil seed bank, and that quadrats at relatively higher elevations had fewer seeds. The species composition had more similarity in the seed bank than in the aboveground vegetation, though the seed bank and aboveground vegetation did change synchronously due to the rapid propagation of annuals. Together, our findings suggest that the combined effects of environmental factors and plant life forms determine the species composition and size of soil seed banks in deserts. Thus, if degraded desert ecosystems are left to regenerate naturally, the lack of shrub and perennial herb seeds could crucially limit their restoration. Human intervention and management may have to be applied to enhance the seed abundance of longer-lived lifeforms in degraded deserts.

scholarly journals Characterization of the genetic architecture underlying eye size variation within Drosophila melanogaster and Drosophila simulans

2019 ◽  
Author(s):  
Pedro Gaspar ◽  
Saad Arif ◽  
Lauren Sumner-Rooney ◽  
Maike Kittelmann ◽  
Andrew J. Bodey ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Variation ◽  
Size Variation ◽  
Eye Size ◽  
Specific Variation ◽  
Gene Regulatory ◽  
Morphological Differences ◽  
Genomic Regions ◽  
Insect Eye

AbstractThe compound eyes of insects exhibit striking variation in size, reflecting adaptation to different lifestyles and habitats. However, the genetic and developmental bases of variation in insect eye size is poorly understood, which limits our understanding of how these important morphological differences evolve. To address this, we further explored natural variation in eye size within and between four species of the Drosophila melanogaster species subgroup. We found extensive variation in eye size among these species, and flies with larger eyes generally had a shorter inter-ocular distance and vice versa. We then carried out quantitative trait loci (QTL) mapping of intra-specific variation in eye size and inter-ocular distance in both D. melanogaster and D. simulans. This revealed that different genomic regions underlie variation in eye size and inter-ocular distance in both species, which we corroborated by introgression mapping in D. simulans. This suggests that although there is a trade-off between eye size and inter-ocular distance, variation in these two traits is likely to be caused by different genes and so can be genetically decoupled. Finally, although we detected QTL for intra-specific variation in eye size at similar positions in D. melanogaster and D. simulans, we observed differences in eye fate commitment between strains of these two species. This indicates that different developmental mechanisms and therefore, most likely, different genes contribute to eye size variation in these species. Taken together with the results of previous studies, our findings suggest that the gene regulatory network that specifies eye size has evolved at multiple genetic nodes to give rise to natural variation in this trait within and among species.

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