Recoverability and Vulnerability of Desert Ecosystems

Fact Sheet ◽  
2003 ◽  
Author(s):  
Keyword(s):  
Desert Ecosystems

scholarly journals Arbuscular Mycorrhizal Fungal Communities in the Soils of Desert Habitats

2021 ◽  
Vol 9 (2) ◽  
pp. 229
Author(s):  
Martti Vasar ◽  
John Davison ◽  
Siim-Kaarel Sepp ◽  
Maarja Öpik ◽  
Mari Moora ◽  
...  
Keyword(s):  
Plant Root ◽  
Significant Proportion ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Illumina Miseq ◽  
Desert Ecosystems ◽  
Fungal Dna ◽  
Root Symbionts ◽  
Arbuscular Mycorrhizal Fungal

Deserts cover a significant proportion of the Earth’s surface and continue to expand as a consequence of climate change. Mutualistic arbuscular mycorrhizal (AM) fungi are functionally important plant root symbionts, and may be particularly important in drought stressed systems such as deserts. Here we provide a first molecular characterization of the AM fungi occurring in several desert ecosystems worldwide. We sequenced AM fungal DNA from soil samples collected from deserts in six different regions of the globe using the primer pair WANDA-AML2 with Illumina MiSeq. We recorded altogether 50 AM fungal phylotypes. Glomeraceae was the most common family, while Claroideoglomeraceae, Diversisporaceae and Acaulosporaceae were represented with lower frequency and abundance. The most diverse site, with 35 virtual taxa (VT), was in the Israeli Negev desert. Sites representing harsh conditions yielded relatively few reads and low richness estimates, for example, a Saudi Arabian desert site where only three Diversispora VT were recorded. The AM fungal taxa recorded in the desert soils are mostly geographically and ecologically widespread. However, in four sites out of six, communities comprised more desert-affiliated taxa (according to the MaarjAM database) than expected at random. AM fungal VT present in samples were phylogenetically clustered compared with the global taxon pool, suggesting that nonrandom assembly processes, notably habitat filtering, may have shaped desert fungal assemblages.

scholarly journals Temporal and Spatial Dynamics of Dark Septate Endophytes in the Roots of Lycium ruthenicum in the Desert Region of Northwest China

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 648
Author(s):  
Li Han ◽  
Jingxin Shi ◽  
Chao He ◽  
Xueli He
Keyword(s):  
Species Diversity ◽  
Spatial Dynamics ◽  
Northwest China ◽  
Dark Septate Endophytes ◽  
Desert Ecosystems ◽  
Lycium Ruthenicum ◽  
Different Seasons ◽  
Application Potential ◽  
First Time ◽  
Hydrolyzable Nitrogen

With the intensification of desertification in northwest China, drought has become a serious environmental problem restricting plant growth and ecological restoration. Recently, dark septate endophytes (DSEs) have attracted more attention because of their ability to improve plants’ resistance to drought. Here, we investigated DSE colonization and species diversity in roots of Lycium ruthenicum collected from Anxi and Minqin, in northwest China, during July, September, and December 2019. This study aimed to evaluate the influence of seasonality and sampling sites on DSEs. In different seasons, DSE colonization varied with the phenology of L. ruthenicum. At different sites, DSE colonization significantly differed. Four isolates were reported in desert ecosystems for the first time. The results showed microsclerotial colonization was directly affected by changing seasons, while hyphal colonization and species diversity were directly affected by sampling sites. The soil organic carbon, pH, alkaline phosphatase, and alkali-hydrolyzable nitrogen were the main predictors of DSE colonization and species diversity. We conclude that DSE colonization and diversity showed significant spatial–temporal heterogeneity and were closely related to soil factors. This research provides a basis for the further understanding of the ecological functions of DSEs and their application potential for vegetative restoration and agricultural cultivation in drylands.

Evidence for direct water absorption by the shoot of the desiccation-tolerant plant Vellozia flavicans in the savannas of central Brazil

2005 ◽  
Vol 21 (5) ◽  
pp. 585-588 ◽  
Author(s):  
Rafael S. Oliveira ◽  
Todd E. Dawson ◽  
Stephen S. O. Burgess
Keyword(s):  
Water Absorption ◽  
Moisture Absorption ◽  
Terrestrial Plants ◽  
Desert Ecosystems ◽  
Common View ◽  
Central Brazil ◽  
Tolerant Plants ◽  
Aerial Roots ◽  
Alternative Water ◽  
Specialized Structure

Our common view on water uptake by terrestrial plants is that it occurs via absorption by roots from the soil substrate. However, it has long been known that plants exhibit alternative water-absorption strategies, particularly in drought-prone environments. Examples include many tropical epiphytic orchids which use a specialized structure called velamen radicum around their aerial roots for moisture absorption directly from the air (Capesius & Barthlott 1975), specialized trichomes in bromeliads (Andrade 2003, Benzing 1990), uptake by hydathodes into leaves of species inhabiting dry desert ecosystems of Namibia (Martin & von Willert 2000) and foliar absorption by coastal California redwoods during the summer fog season (Burgess & Dawson 2004). One of the most intriguing and yet, least-studied examples of adaptations to severe water limitation is found with desiccation-tolerant plants (also called resurrection plants). During drought periods, the water content of these plants can equilibrate with the low relative humidity of the air to the point that the plants appear dead. However, when water is supplied, these plants fully rehydrate (Alpert 2000, Bewley & Krochko 1982) and become physiologically active. Desiccation-tolerant vascular plants are rare in most ecosystems but diverse in tropical inselbergs (granitic outcrops; Porembski & Barthlott 2000). Relatively little is known about inselberg species particularly from an ecophysiological perspective (see Lüttge 1997 and Klüge & Brulfert 2000 for reviews).

scholarly journals Soil moisture modifies the response of soil respiration to temperature in a desert shrub ecosystem

2014 ◽  
Vol 11 (2) ◽  
pp. 259-268 ◽  
Author(s):  
B. Wang ◽  
T. S. Zha ◽  
X. Jia ◽  
B. Wu ◽  
Y. Q. Zhang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Seasonal Cycle ◽  
Northwest China ◽  
Interactive Effects ◽  
Co2 Efflux ◽  
Diel Variation ◽  
Desert Ecosystems ◽  
Volumetric Soil Water Content ◽  
Desert Shrub

Abstract. The current understanding of the responses of soil respiration (Rs) to soil temperature (Ts) and soil moisture is limited for desert ecosystems. Soil CO2 efflux from a desert shrub ecosystem was measured continuously with automated chambers in Ningxia, northwest China, from June to October 2012. The diurnal responses of Rs to Ts were affected by soil moisture. The diel variation in Rs was strongly related to Ts at 10 cm depth under moderate and high volumetric soil water content (VWC), unlike under low VWC. Ts typically lagged Rs by 3–4 h. However, the lag time varied in relation to VWC, showing increased lag times under low VWC. Over the seasonal cycle, daily mean Rs was correlated positively with Ts, if VWC was higher than 0.08 m3 m−3. Under lower VWC, it became decoupled from Ts. The annual temperature sensitivity of Rs (Q10) was 1.5. The short-term sensitivity of Rs to Ts varied significantly over the seasonal cycle, and correlated negatively with Ts and positively with VWC. Our results highlight the biological causes of diel hysteresis between Rs and Ts, and that the response of Rs to soil moisture may result in negative feedback to climate warming in desert ecosystems. Thus, global carbon cycle models should account the interactive effects of Ts and VWC on Rs in desert ecosystems.

scholarly journals Desertification in Forest, Range and Desert Landuses of Tehran Province, Under the Impact of Climate Change

2016 ◽  
Author(s):  
Hadi Eskandari Dameneh ◽  
Moslem Borji ◽  
Hassan Khosravi ◽  
Ali Salajeghe
Keyword(s):  
Climate Change ◽  
Primary Production ◽  
Net Primary Production ◽  
Degradation Process ◽  
Early Warning Systems ◽  
Land Uses ◽  
Emission Scenarios ◽  
Desert Ecosystems ◽  
Tehran Province ◽  
The Impact

Abstract. Persistence of widespread degradation in arid and semi-arid region of Iran necessitates using of monitoring and evaluation systems with appropriate accuracy to determine the degradation process and adoption of early warning systems; because after transition from some thresholds, effective reversible function of ecosystems will not be very easy. This paper tries to monitor the degradation and desertification trends in three land uses including range, forest and desert lands affected by climate change in Tehran province for 2000s and 2030s. For assessing climate changes of Mehrabad synoptic stations the data of two emission scenarios including A2 and B2 were used using statistical downscaling techniques and data generated by SDSM model. The index of net primary production resulting from MODIS satellite images was employed as an indicator of destruction from 2001 to 2010. The results showed that temperature is the most effective driver force which alters the net primary production in rangeland, forest and desert ecosystems of Tehran province. On the basis of monitoring findings under real conditions, in the 2000s, over 60 % of rangelands and 80 % of the forests have been below the average production in the province. On the other hand, the long-term average changes of NPP in rangeland and forests indicated the presence of relatively large areas of these land uses with production rate lower than the desert. The results also showed that, assuming the existence of circumstances of each emission scenarios, the desertification status will not improve significantly in the rangelands and forests of Tehran province.

scholarly journals Facilitation by nurse plants contributes to vegetation recovery in human-disturbed desert ecosystems

2016 ◽  
Vol 9 (5) ◽  
pp. 485-497 ◽  
Author(s):  
Ernesto I. Badano ◽  
Omar R. Samour-Nieva ◽  
Joel Flores ◽  
José L. Flores-Flores ◽  
Jorge A. Flores-Cano ◽  
...  
Keyword(s):  
Vegetation Recovery ◽  
Desert Ecosystems ◽  
Nurse Plants

scholarly journals Comparative whole-genome analysis of a Thar desert strain Streptomyces sp. JB150 provides deep insights into the encoded parvome and adaptations to desert edaphic system

2021 ◽  
Author(s):  
Dharmesh Harwani ◽  
Jyotsna Begani ◽  
Jyoti Lakhani
Keyword(s):  
Genome Mining ◽  
Compatible Solutes ◽  
Gene Clusters ◽  
Flavin Mononucleotide ◽  
Thar Desert ◽  
Secretion Systems ◽  
Desert Ecosystems ◽  
Whole Genome Analysis ◽  
Genetic Traits ◽  
Metabolic Versatility

AbstractWe sequenced the genome of Streptomyces sp. JB150, isolated from a unique site of the Thar desert in India. Genome mining of the JB150 genome revealed the presence of many interesting secondary metabolic biosynthetic gene clusters (BGCs). The encoded parvome of JB150 includes non-ribosomal peptides, polyketides including β-lactone, butyrolactone, ectoine, lantipeptides, lasso peptides, melanin, resorcinol, siderophores, terpenoids, thiopeptides, and other types of hybrid compounds. Among them, ~30% BGCs displayed a high degree of novelty. The genome of JB150 was enriched for a large assortment of specialized genes coding for the production of many interesting biomolecules comprising compatible solutes, multiple stress-response regulators, transport proteins, protein secretion systems, signaling molecules, chaperones and storage reserves, etc. The presence of diverse members of CAZymes enzyme families, high numbers of riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), trehalose and aromatic compounds synthesis genes, putative orthologues to several of the classical fatty acid synthesis components, prototrophy for many essential amino acids exhibit metabolic versatility of JB150 to inhabit in the extreme desert environment. Besides, the genome of JB150 was observed to specifically encode thiazole-oxazole-modified thiazolemicrocin (TOMM) and ectoine. The comparison of the complete genomes of Streptomyces sp. JB150 and seven other actinomycete strains belonging to different desert ecosystems unveiled the presence of many previously undetected, distinctive, biological, and genomic signatures. We propose that these genetic traits endowed by these strains are essential for their adaptation in the highly underprivileged, extreme ecosystem of the Thar desert to cope with multiple abiotic stressors, oligotrophic nutrient conditions and to produce a huge repertoire of diverse secondary metabolites.

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.

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