Harnessing plant-soil-microbiome synergy for resilient desert restoration

Summary

Deserts cover one-third of Earth’s land and support life forms uniquely adapted to extreme climatic and environmental conditions. Restoring these ecosystems remains difficult and costly, yet knowledge of native plants, soils, and their associated microbiomes offers promising solutions. This review outlines the drivers and consequences of desertification feedback loops and explains how microbial adaptations sustain soil functions under stress. We highlight the role of plant–microbe–soil interactions in shaping functional networks that support restoration and the development of synergistic plant communities. We also highlight how the integration of ecological frameworks such as niche differentiation, network theory, and stoichiometric balance reveals new directions for restoration efforts. In this framework, emerging microbiome-based strategies can offer a path to transform barren or degraded landscapes into diverse, resilient vegetative islands.

Graphical abstract

Microbiology; Applied microbiology; Plant Biology; Plant ecology; Soil ecology.

Desertification and barren lands with sparse vegetation

Desertification refers to the transformation of productive drylands into degraded, infertile landscapes under the combined pressures of harsh climate and unsustainable land use. Desert ecosystems face extreme environmental conditions and scarce resources, which present significant challenges for sustainable and effective restoration.¹ Human activities and climate change act as major drivers of soil degradation and desertification.² These changes result in the breakdown of aggregates, organic matter removal, and nutrient depletion, resulting in reduced carbon storage and CO₂ release, reinforcing climate warming. Desertification and climate change are interconnected through interdependent feedback loops that exacerbate their progression and amplify global challenges (Figure 1). For example, climate change drives desertification as temperatures rise and precipitation declines, while desertification reduces vegetation cover, leads to soil degradation, and further intensifies warming and CO₂ levels. Desertification also causes the loss of essential nutrients and organic matter, disrupting nutrient cycles and impairing microbial activity in the soil.³ Moreover, unpredictable and low precipitation events further disrupt natural soil structure and cause compaction, which leads to decreased infiltration rates and greater susceptibility to wind and water erosion.^4,5 Drylands now face four dominant degradation pathways: (i) wind-driven soil erosion that removes fertile nutrient-rich particles, (ii) salinization arising from groundwater extraction and irrigation return flows, (iii) chronic nutrient depletion under sparse vegetation, and (iv) collapse of biological soil crusts that stabilize surfaces and mediate infiltration.^6,7,8 Therefore, taking advantage of water from precipitation becomes increasingly difficult. These infertile and degraded soils hinder the establishment and survival of plant species and lead to reduced biodiversity and ecosystem instability³ (See further the desertification feedback loops in Figure 1). Hard infrastructure, such as concrete sand fences and chemical soil binders, often delivers short-lived surface stability but ignores ecosystem functioning. In contrast, ecologically based restoration harnesses native species and natural successional processes, restores habitat complexity, and can cut long-term costs relative to mechanical approaches.^9,10

Figure 1.

Desertification feedback loops – drivers and consequences

A schematic illustrates how environmental and human-driven processes interact to accelerate desertification through self-reinforcing feedback loops. The diagram is organized into four clusters and loop color-coded, representing water and erosion factors (purple), soil health factors (green), salinity and alkalinity (red), and urbanization and industrialization issues (blue). The water and erosion cluster depicts processes such as overgrazing, vegetation loss, and increased soil vulnerability that collectively reduce water availability and intensify erosion. The soil health cluster emphasizes the loss of organic matter, nutrient depletion, and declining microbial activity, which lead to overall soil degradation. The salinity/alkalinity cluster addresses increased salinity stress, the formation of alkaline soils, and nutrient precipitation that impedes plant growth and limits the expansion of vegetation, leading to urban increase and high soil heat and air pollution. Industrial influences further increase soil contamination and exacerbate land degradation. Arrows represent cause-and-effect relationships, and the labeled loops underscore the cyclic nature of these interactions, where each process reinforces and magnifies the impact of others, driving the progression of desertification. Created in BioRender. Elhady, A. (2025) https://BioRender.com.

The establishment of plants in desert ecosystems is confined to a complex process influenced by various abiotic factors, as explained in the previous paragraph. These challenges slow the colonization and growth of plant species, which results in sparse and fragmented vegetation. This fragmentation limits the development of favorable microhabitats and reduces facilitative interactions that support plant recruitment and community establishment.^11,12 The harsh desert conditions impose significant physiological stress on germinated seeds and young seedlings, which diminishes their survival rates and impedes vegetation establishment.¹³ This cycle of sparse plant cover and limited recruitment perpetuates the vulnerability of these ecosystems to external disruptions. A recent study in the western Sonoran Desert found that gap soils between vegetation patches have lower microbial diversity, richness, nutrient content, and organic nitrogen mineralization capacity than canopy soils, a disparity that, without intervention, may accelerate desertification.¹⁴ Growing evidence suggests that soil properties and the associated microbiomes play a substantial role in modulating nutrient availability, water retention, and microbial interactions essential for plant growth.^15,16 On the other side, soil biological activities within vegetation patches are enriched in root system establishment, which promotes nutrient cycling and microbial colonization. In addition, the canopy cover regulates the soil microclimate by reducing temperature fluctuations and preserving moisture levels. Moreover, vegetation patches can absorb or retain water from surrounding areas, but their effectiveness depends on species composition, density, and root depth, which shape their function. For example, large trees within these patches contribute to herbaceous species richness by modifying light availability and water competition.^17,18 Soil N, P, and K often accumulate beneath woody shrubs, generating “islands of fertility” while the spaces between canopies remain nutrient-poor.¹⁹ As shrubs occupy interspaces, they reinforce their own spread and drive regional climate shifts via changes in albedo and dust fluxes. In the Atacama Desert, the herbaceous halophyte Distichlis spicata creates nutrient hotspots and enhances soil water content and phosphorus availability, stimulating microbial activity and promoting soil rehabilitation. This effect was accompanied by the active removal of salt from the rhizosphere and microbial activity.²⁰

Recent evidence shows that assemblies of drought-adapted plants with compatible microbiomes, inoculated biocrust propagules, and diazotrophic consortia accelerate soil aggregation, organic-matter accumulation, and nutrient turnover, which raises seedling establishment within three growing seasons. These plant–soil–microbe synergies thus could provide a scalable, process-based pathway for restoring ecological function across degraded deserts.^21,22,23 Many microbes in the desert soil can assume dormant stages, prolong their survival while not contributing to ecosystem functions and services. Meanwhile, desert microbes exhibit remarkable adaptations that enable them to persist and maintain energy and growth in resource-limiting environments.²⁴ However, these microbes are challenged by significant abiotic stresses such as low precipitation, temperature fluctuations, intense solar radiation, high soil salinity, and a lack of vegetation and organic carbon. These microbes have developed adaptive strategies such as producing stress-response proteins, optimizing metabolism, and modifying cell membranes to conserve scarce resources, which support energy maintenance and growth in resource-limited environments (Box 1).

Figure 2.

Microbial survival, persistence, and energy acquisition in desert soils

Microbial cells enter extended dormant states under extreme environmental stress, including high or low temperatures, intense UV radiation, and prolonged drought. When exposed to temporary periods of favorable conditions, these microbes rapidly resume transient metabolic activities and proliferation. Microbes employ diverse strategies, such as photosynthesis, chemosynthesis, and trace gas consumption for energy acquisition. Cyanobacteria and hydrogen-oxidizing bacteria (HOB) utilize specialized enzymes, including RuBisCO and hydrogenase, to convert inorganic carbon into biomass, supporting ecosystem resilience in harsh desert environments. Created in BioRender. Elhady, A. (2025) https://BioRender.com/h75n971.

Box 1. Desert microbes persist and maintain their energy and growth in harsh environments.

To survive under these highly challenging and fluctuating conditions, microbial cells enter intermittent dormant states^25,26 and resume active metabolism related to DNA repair and energy generation when temporary favorable conditions arise (Figure 2). For instance, cyanobacteria, which have the advantage of being independent of receiving organic carbon from vegetation, can induce ROS scavenging and the production of osmoprotectants during dormancy, while rehydration upregulates RuBisCO transcripts to acquire carbon and energy through H₂ oxidation and phototrophy. This cycle could explain the resilience and persistence that allow microbes to survive in the harsh conditions of desert ecosystems.²⁶ On the other hand, these microbes employ diverse strategies for energy acquisition, including photosynthesis, chemosynthesis, and the consumption of trace gases such as hydrogen (H₂). For example, cyanobacteria, as oxygenic photoautotrophs, trigger their photosynthetic activity and thrive in response to occasional moisture from precipitation or dewfall. Using photosystems and RuBisCO enzymes in the Calvin-Benson-Bassham cycle, they convert CO₂ into organic matter.^27,28 Additionally, hydrogen-oxidizing bacteria (HOB), which are facultative chemolithoautotrophs, play a critical role by oxidizing atmospheric H₂ with the help of the hydrogenase enzyme. This process generates ATP through an electron transport chain and facilitates CO₂ assimilation into biomass via the same Calvin cycle.²⁹ Other microbes, including Actinobacteria, rely on their metabolic flexibility to exploit scarce energy sources, such as organic compounds and trace gases.^28,30 By sudden temporal rewetting, the soil also causes microbial death through osmotic shock,^31,32 thereby releasing necromass of microbial cells into the soil matrix.³³ This pool of organic matter comprises amino acids, nucleic acids, and cellular polymers that serve as a readily available nutrient source for surviving and reinitiating microbial activities.^33,34

Plant-microbe interactions drive soil functional networks for ecosystem resilience

Plant-microbe interactions are crucial for soil structure and functions, driving nutrient cycling as well as plant growth. These interactions form a complex functional network that contributes to the resilience of ecosystems, particularly in response to environmental stress. Numerous studies emphasize the dynamic interplay between soil, plants, and microbiomes.^35,36

Mechanisms involved in plant-driven restoration

Plant-derived compounds modulate soil properties, shape microbial composition, and result in loops of feedback reactions that enhance interdependent functions (Figure 3). For example, root-exuded amino acids such as arginine and methionine enhance microbial enzymatic activities of sulfur, phosphorus, and nitrogen cycles.³⁷ Other amino acids, such as proline and glutamate, aid in osmoregulation for both plants and microbes. For instance, Bacillus subtilis (BERA 71) and Arbuscular mycorrhizal fungi (AMF) significantly enhanced Acacia gerrardii’s tolerance to salt stress by increasing osmoprotectants such as proline.³⁸ Transplanting deep-rooted Acacia tortilis seedlings inoculated with high-hyphal arbuscular mycorrhizal fungi lifted groundwater and enhanced drought survival.³⁹ After tree establishment, Cenchrus ciliaris seeds were sown in the space between the trees to create rapid ground cover, tapping the lifted moisture, and building a resilient two-layer canopy.^40,41 However, in Arabidopsis, Biotin (Vitamin B7) enhances tolerance to alkaline-salt stress by upregulating BIO2 and reducing reactive oxygen species, which might highlight its potential for desert plant resilience.⁴² Specific compounds such as strigolactones and flavonoids, exuded by roots play a dual role in plant responses to abiotic stresses. They modulate hormonal pathways involving gibberellic acid (GA), cytokinins (CK), auxin, and abscisic acid (ABA), and antioxidant systems, while also facilitating symbiotic interactions with arbuscular mycorrhizal fungi and N₂-fixing bacteria. These interactions enhance root architecture, water uptake, and nutrient acquisition, particularly phosphorus (P) and nitrogen (N), which potentially contribute to plant resilience in arid conditions.^43,44,45 Furthermore, gelatinous mucilage promotes soil aggregate formation and contributes to soil organic carbon while supporting beneficial microbes and fungal-bacterial interactions by providing a matrix, facilitating nutrient exchange, and promoting biofilm formation. In some plant species, mucilage contains uronic acid, which improves soil water retention. This adaptation is evident in many desert grasses, which form rhizosheaths, which are soil aggregates that are tightly bound to roots.^46,47 Rhizosheath development enhances drought tolerance and nutrient uptake by hosting nitrogen-fixing and growth-promoting bacteria^47,48 (Figure 3). Additionally, organic acids, such as citric and malic acids, released by roots mobilize phosphorus and other nutrients by altering soil pH and dissolving mineral-bound nutrients.^49,50 Synergistically, oxalogenic plants and oxalotrophic microbes contribute to long-term carbon stabilization in soils. Oxalogenic plants produce oxalic acid, which can either react with calcium to form stable calcium oxalate crystals in plant tissues or be exuded into the soil, where oxalotrophic microbes further metabolize oxalate as an organic carbon source for growth. Oxalotrophic microbes release carbonate, which in arid alkaline soils can form carbonates with abundant calcium or magnesium, which provide a durable carbon storage mechanism^51,52 (Figures 3 and 4).

Figure 3.

A schematic highlighting the role of plant-derived compounds, such as organic acids, amino acids, and signaling molecules, in modulating soil properties, nutrient availability, and microbial activity

Created in BioRender. Elhady, A. (2025) https://BioRender.com/q97x36.

Figure 4.

Microbiome roles in plant health and soil functions

The diagram shows how microbial groups (blue) support soil (brown) and plant (green) functions, including nutrient cycling, pollutant removal, stress tolerance, and growth promotion. Colored lines link specific microbial roles to plant and soil benefits. Created in BioRender. Elhady, A. (2025) https://BioRender.com/i85v640.

Microbiome-based strategies for desert restoration and conservation

In soil, microbes enhance nutrient cycling, water-holding capacity, pH adjustment, and aggregation, thereby improving soil structure and fertility. Recently, in desert steppes, fungi and bacteria, particularly Actinomycetota, Pseudomonadota, and Ascomycota, significantly contribute to driving litter decomposition.⁵³ Fungi break down lignified compounds,⁵⁴ while bacteria target simpler polysaccharides earlier in decomposition.⁵⁵ These microbes simultaneously promote plant growth as they facilitate nutrient uptake, enhance stress tolerance, suppress diseases, and enable resistance to herbivores and abiotic stressors. Intriguingly, some desert plant endophytic bacteria, such as Enterobacter sp. SA187 can induce resistance to thermal and radiation stress in their colonized hosts by enhancing Heat Stress Protein (HSP) expression and the production of antioxidants,^56,57 thereby fortifying the stress resilience of their desert host plants (Figure 4). In restoration programs, colonization by endophytic fungi promotes early seedling establishment, boosting survival at 45°C–50°C, and reducing the time period of vulnerable establishment.^58,59 Furthermore, mycorrhizal fungi and nitrogen-fixing bacteria have been shown to influence the pH of the rhizosphere, either by adjusting alkalinity or acidity in the nutrient colloidal solution.⁶⁰ Similarly, sulfur-oxidizing bacteria (SOB) also influence pH by regulating sulfur cycling in alkaline habitats.⁶¹ Meanwhile, Enterobacter sp. SA187 alleviates salt-induced hypersensitivity in desert plants and crops by reprogramming the plant sulfur metabolism.^62,63 A common feature of all these endophytic root microbes is that they strongly restructure the root architecture, thereby enhancing access to water and nutrients. For example, under water scarcity, the desert plant endophyte Pseudomonas argentinensis strain SA190 can induce massive growth of tap roots in both desert and non-desert plant species, thereby enhancing water use efficiency and avoiding drought conditions of the colonized plants.⁶⁴ Similarly, the endophytic desert fungus Piriformospora indica colonizes the roots of dicot plants, modifies the root architecture of the colonized host plants, and enhances their resilience to drought and salinity.^65,66 Desert plants often rely on crucial symbiotic relationships with microbes to survive extreme conditions. For example, the desert legume Indigofera argentea fails to thrive in sterile sand unless inoculated with its rhizobial symbiont, Rhizobium sp.⁶⁷ Likewise, many other legumes cannot establish in nutrient-poor soils in the absence of compatible rhizobia. Furthermore, salt-tolerant shrubs such as Suaeda sp. benefit from rhizosphere bacteria such as Halomonas, Marmoricola, and Arthrobacter, which enhance nitrogen cycling and improve plant resilience to salinity, making them vital for restoring saline or degraded desert soils. On the other hand, fungal hyphal networks, particularly those of filamentous and mycorrhizal fungi, act as vital conduits for nutrient, water, and microbial transport in soils. These networks extend beyond plant roots, bridging soil pores and connecting distant microsites.⁶⁸ Mycorrhizal fungi, for instance, transport phosphorus, nitrogen, and water to host plants in exchange for carbon. In arid environments, they also transport carbon into the soil as glomalin,⁶⁹ which enhances soil structure and erosion resistance. In addition, fungal hyphae facilitate microbial dispersal by serving as pathways for bacteria and archaea.⁷⁰ These microorganisms hitchhike along hyphae or reside in thin water films surrounding fungal filaments, accessing new habitats that are otherwise isolated in dry or pore-disconnected soils. Experimental evidence demonstrates that fungal hyphae create oxygen gradients that support anaerobic bacteria in otherwise oxic soil, promoting microbial diversity and ecosystem resilience.⁷⁰ For instance, air-exposed fungal hyphae maintain localized hypoxic conditions that enable anaerobic bacteria such as Clostridium to thrive and disperse between anoxic microsites over distances ranging from millimeters to centimeters.

On the other hand, desert microbes, after long dry periods in dormancy, resume their activity upon rainfall through a sequential “resuscitation cascade,” where microbial groups awaken in stages and prepare conditions for subsequent communities. Immediately after rain, fast-growing, aerobically respiring bacteria and algae are the first to activate, using easily metabolized substrates and oxygen, which results in a nutrient flush (Birch effect).⁷¹ These pioneers alter microsite conditions, such as consuming oxygen or producing organic acids, which allow more specialized organisms to thrive. In the Negev Desert, biological soil crusts exhibit this cascade: Bacillales dominate the initial response, followed by Sphingobacteriales and Alphaproteobacteria as the soil wets and oxygen levels rise.⁷² This resuscitation is not only related to water but also to other nutrients such as nitrogen. For example, Cyanobacteria (Synechocystis sp. PCC 6803) initiate a resuscitation program upon nitrate addition, restore cellular functions, reactivate photosynthesis, and regulate the transition through non-coding RNAs to support colonization in nitrogen-limited environments.⁷³ This resuscitation cascade boosts ecosystem resilience, with each microbial wave performing tasks such as decomposition, nitrogen fixation, or anaerobic fermentation. These processes restore soil functions and organize microbial networks both temporally and spatially. Practically, for example, spraying a slurry of extracellular polymeric substances (EPS) rich cyanobacteria or applying fragmented biocrusts raised aggregate stability by 35% and increased early seedling density on sandy loam in Rajasthan.⁷⁴

Plant-microbe-soil interactions facilitate synergistic plant community establishment: key gaps and prospects

Desert restoration requires holistic strategies that integrate all components and embrace sustainable land management in conjunction with the critical interactions between soil, plants, and microbes (Figures 3 and 4). In desert communities, perennial species create “fertility islands” that contribute to the soil nutrients and organic matter through root exudates. These fertile islands are associated with increased microbial enrichment and diversity,⁷⁵ and facilitate the recruitment of additional plant species and promote the germination of the soil seed bank (Figure 5). Moreover, deep-rooted plants perform nocturnal hydraulic lift, where they transfer deep soil moisture into drier surface horizons. This passive water input sustains microbial hydration and activity at the soil surface, thereby enhancing organic matter decomposition and nutrient cycling.^76,77,78 Here, we present several hypotheses that address key gaps in research that need to be tackled: H1: Specific plant species can enhance soil properties and enrich microbial communities to facilitate the recruitment of further plant species and promote the development of plant community networks. Nurse species create fertile islands that serve as nucleation foci. These islands attract additional plant species, enable their establishment, and accelerate the development of interconnected plant community networks. Restoration ecologists used to employ the nucleation model, in which small facilitator patches act as recruitment hubs and expand outward as animals disperse seeds into improved microsites. For example, long-term Sonoran Desert records indicate that these patches drive vegetation change for decades despite highly variable rainfall.^79,80,81 H2: The capacity of soil to support further plant species varies depending on the initiating plant species and the soil type, which initiates specific changes in soil properties and microbial community composition; H3: The recruitment of subsequent plant species is influenced by legacy feedbacks from the primary plant species, which shape soil properties, nutrient availability, and microbial communities over time. These feedbacks are driven by ecological processes such as soil modification, microbial succession, and plant-microbe interactions. Temporal and disturbance-related factors, such as drought or fire, further influence the resilience of microbial communities and the ability of new plants to establish. As a result, the success of plant recruitment is strongly linked to both the initial plant-microbe interaction and the ongoing ecological feedback that emerges from these interactions (Figure 6). Practically, certain functional traits of plants promote microbial functions and soil nutrient cycling, which support desert land restoration. For instance, a study in the Gobi Desert highlighted that planting salt- and drought-tolerant vegetation improved soil moisture retention and gradually reduced salinity, which facilitated microbial activity.⁸² Nutrient-enriching traits, such as nitrogen fixation, accelerate soil restoration, as seen in legumes such as Indigofera argentea, which enhance nitrogen availability via Rhizobium symbiosis.⁶⁷ Deep-rooted species redistribute water and nutrients to surface soils, while halophytes remove excess salts and reclaim degraded lands.⁸³ Litter quality and root traits affect microbial functions, as species with phosphorus-rich leaves promote microbial growth and decomposition, while fibrous-rooted grasses increase microbial biomass through fine root inputs.⁸⁴ Tap-rooted shrubs that perform hydraulic lift enhance moisture availability for both microbes and co-occurring plants.⁸⁵ Therefore, selecting species with targeted functional traits can be essential in restoration efforts to optimize nutrient cycling and support microbial ecosystem recovery.

Figure 5.

Plant-soil-microbe interactions contribute to ecosystem restoration and functionality

The mechanistic model highlights the role of plant roots and soil microbiota in ecosystem restoration. Early root growth promotes the secretion of root exudates, triggering microbial recruitment and rejuvenation. These microbes facilitate organic matter decomposition, nutrient mobilization, and symbiotic associations that enhance soil fertility and structure. The enriched soil supports canopy and root expansion and promotes an integrated microhabitat for flora and fauna, enabling sustained ecosystem recovery. Created in BioRender. Elhady, A. (2025) https://BioRender.com/n49z805.

Figure 6.

A proposed framework addressing the roles of plant-soil feedback in shaping soil properties and plant community dynamics

Plant A influences soil properties by enriching specific microbial taxa and promoting soil structure and fertility. The resulting soil conditions differentially support the establishment and growth of other plant species (plants B–E), highlighting the need to investigate the extent and mechanism of this feedback to optimize plant community assembly and ecosystem restoration strategies. Created in BioRender. Elhady, A. (2025) https://BioRender.com/g20q876.

Integration of ecological frameworks for plant-microbial community assembly in desert restoration programs

The establishment of plant communities involves complex and diverse interactions underpinned by environmental factors. These interactions are often explained by well-established theories, such as niche differentiation, resource partitioning, and network theory, which influence species complementarity and community stability.^86,87 However, studies on plant network assembly have largely overlooked the roles of soil and associated microbiomes. This raises a critical question: To what extent do soil microbial taxa, shaped by long-term selection and evolutionary changes, contribute to the complementarity and stability of plant species within community networks? These aspects of plant-microbe interactions may explain the frequent failures of tree plantations, as they often fail to establish the connectedness and nestedness required for stable and functional community networks. Long-term selection and evolutionary adaptations in soil microbes could promote a dynamic interplay of positive and negative feedback that profoundly affects plant complementarity and stability in community networks.^88,89 Co-evolved symbionts, such as arbuscular mycorrhizal fungi, often confer differential benefits to host plants, which promote niche partitioning and minimize direct competition.^90,91 Specialized pathogens can drive negative plant–soil feedback to prevent single-species dominance, thus regulating plant coexistence and enhancing overall diversity,^92,93 probably according to the “Janzen–Connell” hypothesis. Microbial legacies that develop under particular plant lineages may dictate future assembly and guide both early and late successional stages. Earlier work demonstrated that microbial communities adapt to dominant plants, with their long-term legacy either accelerating or constraining community reassembly after disturbance.⁹⁴ Moreover, plant–microbe networks exhibit nested or modular structures, where co-evolved soil microbes form stabilizing hubs that keep the network functional despite disturbances and protect communities from environmental stress.⁸⁶ Such facilitation underpins restoration initiatives; inoculation with native soil biota can strengthen plant complementarity, promote resilience, and bolster biodiversity outcomes. The “ecological stoichiometry” is another relevant theory that examines the consequences of chemical elemental imbalances in ecological interactions, such as those between plants and their environment, including soil. Most stoichiometric studies focus on specific macroelements such as C, N, and P, but attention is growing toward other essential elements in ecosystem dynamics.^95,96,97 The role of stoichiometric ratios in plant community establishment, particularly in relation to the balance of essential chemical elements and microbial interactions, remains poorly understood in desert ecosystems. Additionally, their potential applications in restoration programs have yet to be explored. Microbiome-steering interventions that target stoichiometric constraints could realign elemental ratios toward the optima predicted by ecological stoichiometry and enhance early restoration success.⁹⁸ In desert ecosystems, species diversity in the Ebinur Lake basin desert depends on soil and leaf stoichiometric ratios, particularly leaf C: P, leaf C: N, and soil C: P ratios, which significantly influence species diversity.⁹⁷ In the Qinghai–Tibet Plateau desert ecosystem, vegetation and precipitation control topsoil stoichiometric properties.⁹⁹ However, these studies did not account for the role of microbial communities. Only a few studies have examined microbial metabolism via soil extracellular enzyme stoichiometry in the northwestern desert of China, underscoring microbial contributions to nutrient cycling.⁸³ Furthermore, nitrogen addition in desert steppes alters nutrient stoichiometry in plants, litter, and microbes, with plant functional traits influencing nutrient-cycling responses.¹⁰⁰

Likewise, the growth rate hypothesis (GRH), which is tightly related to the stoichiometry theory, has not been extended to the plant community and microbial dynamics in desert ecosystems. The GRH predicts that faster-growing organisms require more phosphorus for nucleic acid synthesis, particularly ribosomal RNA, essential for protein production and cell division.^101,102 In the context of plant community succession, nutrient limitations often characterize early successional stages or disturbed ecosystems.¹⁰³ Early colonizers, such as grasses or herbaceous plants, typically possess higher and rapid growth rates that align with the GRH, where nutrient availability (such as phosphorus) supports their rapid nucleic acid synthesis. These species, with low leaf mass per area and short lifespans, rapidly colonize disturbed areas by efficiently utilizing available resources.¹⁰⁴ Later, such colonizers enhance soil nutrient content through biomass accumulation and organic matter inputs, paving the way for slower-growing species. As succession progresses and nutrient cycling stabilizes, species with resource conservation strategies, such as shrubs or trees, gain a competitive advantage and create conditions for the establishment of a more diverse and stable community. Microbial processes that mediate nutrient availability, such as phosphorus, can influence plant competition and coexistence, which can lead to community establishment. Mycorrhizal associations, for instance, enhance phosphorus acquisition and may preferentially benefit late-successional species with slower growth rates.^105,106 These plant-microbe influences might ensure a gradual transition from nutrient-limited conditions dominated by early successional plants to nutrient-enriched soils capable of sustaining climax communities.

Microbial interventions for diverse and resilient vegetative islands

In many dryland sites, initial vegetation stands (often dominated by a single species or a few species) struggle to support other plants due to limited nutrient availability, harsh microclimatic conditions, and inadequate microbial networks. Desert restoration could rely on mixing complementary plant functional traits to engineer belowground niches and recruit diverse microbial consortia.^107,108 Spatial interspersion of phreatophytes lifts groundwater into surface soils and forms fertility islands under their canopies. These islands buffer temperature extremes, sustain higher soil moisture, and support richer microbial communities alongside improved seedling survival.¹⁰⁹ Legumes, grasses, and nurse shrubs enrich the soil via diazotrophic symbioses that increase microbial biomass N and create rhizosphere moisture microenvironments, favoring other microbes with complementary traits.^110,111,112

Practitioners can systematically expand existing vegetative islands and promote greater plant diversity through integrating microbial-based solutions into desert restoration (Figure 7). Introducing or amplifying co-evolved, locally adapted microbes (such as arbuscular mycorrhizal fungi; rhizobia; Pseudomonas; Bacillus; and Burkholderia) around these established “nurse plants” can enrich the soil environment by improving nutrient cycling, retaining soil moisture, and suppressing harmful pathogens. Meanwhile, soil inoculation with crust-forming organisms in biocrust slurries stabilizes the substrate and initiates nutrient cycles.^113,114 Therefore, biocrusts could function as connective nodes across plants, soils, and microorganisms, stabilize bare surfaces, and strongly curb wind erosion.¹¹⁵ Their microbial consortia fix and transform nitrogen and exchange reactive gases such as nitric oxide (NO) and nitrous acid (HONO); microtopography and surface chemistry retain seeds and shape species-specific germination and seedling survival.^116,117 In restoration contexts, biocrust inoculation with site amelioration accelerates recovery of soil stability and core functions and improves native plant establishment, so biocrust deployment serves as a practical tool for desert rehabilitation.¹¹⁸

Figure 7.

Transitions from sparse, low-diversity vegetation and limited microbial communities to robust, interconnected plant–microbial networks

Over time, this cascading effect yields diverse, interconnected vegetative patches that improve habitat quality, enhance soil stability, and strengthen overall ecosystem function. Harnessing the synergistic relationships between plants and soil microbes, practitioners can transform isolated vegetative islands into thriving resource hubs that support a wide range of plant species, thereby fostering more resilient desert ecosystems. Created in BioRender. Elhady, A. (2025) https://BioRender.com/y38ej4x.

When early colonizers or pioneer trees gain enhanced access to nutrients, water, and microbial symbionts, they shift from being isolated, less diverse “islands” to resource hubs that encourage secondary plant establishment. Such microbial interventions support the concept of increased complementarity among plant species. For instance, one plant species may specialize in fixing atmospheric nitrogen through rhizobia, while another relies on mycorrhizal fungi for phosphorus acquisition. Together, they form a more productive and stable plant assembly than either could alone. Furthermore, harnessing adaptive soil biota, particularly microbes evolved under local drought or salinity regimes, heightens desert plant resilience and amplifies nurse effects. Strategic inoculation or facilitation of these microbes can expand vegetative islands outward from existing stands, creating new microsites favorable to different plant functional groups. Over time, this effect causes a cascade that yields diverse, interconnected vegetative patches, ultimately improving habitat quality, soil stability, and overall ecosystem function.

Conclusions

Deserts constitute extensive landscapes that still harbor numerous undiscovered ecological and biogeochemical phenomena. While some deserts are natural, many are manmade, driven by desertification from population growth, inappropriate land use, and climate change. Therefore, land restoration and changes in agricultural practices are necessary to turn land back into functioning ecosystems. While drylands with residual vegetation can probably be restored, hyper-arid deserts demand more sophisticated approaches beyond simply planting trees. The soil-plant-microbiome forms an integral part of the desert ecosystem, where all parts must work together in a balanced way, and projects that focus only on one aspect will stand little chance of success. Desert restoration strategies must match the soil’s physical, chemical, and biome structures with native, locally adapted plants and microbial species. A deep understanding of plant growth rate, elemental stoichiometry, and successional dynamics can guide species selection in nutrient-poor ecosystems. Finally, additional research into the mechanisms and quantification of feedback effects could form the basis for transformative strategies in ecological engineering and restoration ecology.

Outstanding research questions

• (1)To what extent do elemental stoichiometric imbalances in desert soils limit ecological restoration success, and how can microbial inoculation and other microbiome steering practices re-establish nutrient homeostasis?
• (2)How can the growth rate hypothesis (GRH) principles be applied to design effective species combinations for revegetation in degraded ecosystems?
• (3)How do microbial legacy effects shape plant community composition and functional diversity across successional stages?
• (4)What strategies can optimize the use of pioneer species to accelerate succession and improve ecosystem resilience under varying environmental conditions?

Acknowledgments

The authors thank the members of the Hirt lab for their insightful discussions on desert ecosystems and desertification mitigation. Appreciation is also extended to collaborators and funding bodies for their support in advancing this research. The work was funded by the KAUST fund BAS/1/1062-01-01 to HH as part of the DARWIN21 desert initiative (http://www.darwin21.org/).

Author contributions

AE and HH conceptualized and outlined the structure of the review article. AE and HH conducted the literature search and synthesized findings across studies. AE wrote the draft of the article; AE conceptualized and designed the figures. HH and AE reviewed and revised the text and approved the final version for submission.

Declaration of interests

The authors declare no competing interests.