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During the United Nation's Decade on Ecosystem Restoration, planting material shortages are constraining restoration, while climate change exacerbates the need for restoration and reduces recruitment. Concurrently, research shows that native mycorrhizal fungi (symbiotic with plant roots) appropriate to plant provenance and site conditions significantly accelerate restoration, support crucial ecosystem services, and provide natural climate solutions (sequestering carbon), and nature-based solutions for climate change (climate adaptation). We reviewed 130 management plans for natural areas in the United States to evaluate whether restoring native mycorrhizal communities has translated into implementation. Although management plans frequently discussed the ecosystem services mycorrhizal fungi provide, nearly one half (46%) viewed fungi solely as pathogens or ignored them altogether. Only 8% of plans mentioned mycorrhizal fungi. Only one plan mentioned that mycorrhizae were potentially helpful to natural regeneration, while one other mentioned utilizing soil as a restoration tool. Our examination of publicly available data and case studies suggests that relatively meager protections for fungi, limited research funding and resulting data, research difficulty, and limited access to mycology experts and training contribute to this gap between science and implementation. A database of literature showcasing mycorrhizal ecosystem services and benefits is provided to highlight when and why mycorrhizae should be considered in management, regeneration, and restoration. Three action items are recommended to safeguard native mycorrhizal fungal communities and accelerate restoration and regeneration. Ten implementation tips based in scientific literature are provided to clarify the need and methods for mycorrhizal restoration

The aboveground impacts of climate change receive extensive research attention, but climate change could also alter belowground processes such as the delicate balance between free-living fungal decomposers and nutrient-scavenging mycorrhizal fungi that can inhibit decomposition through a mechanism called the Gadgil effect. We investigated how climate change-induced reductions in plant survival, photosynthesis and productivity alter soil fungal community composition in a mixed arbuscular/ectomycorrhizal (AM/EM) semiarid shrubland exposed to experimental warming (W) and/or rainfall reduction (RR). We hypothesised that increased EM host plant mortality under a warmer and drier climate might decrease ectomycorrhizal fungal (EMF) abundance, thereby favouring the proliferation and activity of fungal saprotrophs. The relative abundance of EMF sequences decreased by 57.5% under W+RR, which was accompanied by reductions in the activity of hydrolytic enzymes involved in the acquisition of organic-bound nutrients by EMF and their host plants. W+RR thereby created an enhanced potential for soil organic matter (SOM) breakdown and nitrogen mineralisation by decomposers, as revealed by 127-190% increases in dissolved organic carbon and nitrogen, respectively, and decreasing SOM content in soil. Climate aridification impacts on vegetation can cascade belowground through shifts in fungal guild structure that alter ecosystem biogeochemistry and accelerate SOM decomposition by reducing the Gadgil effect. Keywords: Gadgil effect; dissolved nitrogen; dissolved organic carbon; extracellular hydrolytic soil enzymes; fungal functional guilds; mixed arbuscular/ectomycorrhizal (AM/EM) ecosystems; mycorrhizal nutrient economy.

1. Climate change will increase heat and drought stress in many dryland areas, which could reduce soil nutrient availability for plants and aggravate nutrient limitation of primary productivity. Any negative impacts of climate change on foliar nutrient contents would be expected to negatively affect the photosynthetic capacity, water use efficiency and overall fitness of dryland vegetation. 2. We conducted a 4‐year manipulative experiment using open top chambers and rainout shelters to assess the impacts of warming (~2°C, W), rainfall reduction (~30%, RR) and their combination (W + RR) on the nutrient status and ecophysiological performance of six native shrub species of contrasting phylogeny in a semi‐arid ecosystem. Leaf nutrient status and gas exchange were assessed yearly, whereas biomass production and survival were measured at the end of the study. 3. Warming (W and W + RR) advanced shoot growth phenology and reduced foliar macro‐ (N, P, K) and micronutrient (Cu, Fe, Zn) concentrations (by 8%–18% and 14%–56% respectively), net photosynthetic rate (32%), above‐ground biomass production (28%–39%) and survival (23%–46%). Decreased photosynthesis and growth in W and W + RR plants were primarily linked to enhanced nutritional constraints on carbon fixation. Poor leaf nutrient status in W and W + RR plants partly decoupled carbon assimilation from water flux and led to drastic reductions in water use efficiency (WUEi; ~41%) across species. The RR treatment moderately decreased foliar macro‐ and micronutrients (6%–17%, except for Zn) and biomass production (22%). The interactive impacts of warming and rainfall reduction (W + RR treatment) on plant performance were generally smaller than expected from additive single‐factor effects. 4. Synthesis. Large decreases in plant nutrient pool size and productivity combined with increased mortality during hotter droughts will reduce vegetation cover and nutrient retention capacity, thereby disrupting biogeochemical processes a

Drylands cover around 41% of Earth’s land surface and include 20% of the major centers of global plant diversity. Drylands are especially vulnerable to climate change and desertification. Maintenance of biodiversity in drylands is crucial to prevent those negative impacts. In order to do so, it is important to understand how dryland plant communities are organized and the processes that allow plant species coexistence in these severely water limited environments. Afforested plantations of Pinus halepensis Mill., that were extensively planted in semiarid areas of the Mediterranean basin during the second half of the XXth century are particularly vulnerable to climate change and drought intensification. The aim of the present PhD thesis was to investigate the water use strategies of some of the most common plant species naturally occurring in the semiarid Iberian SE, and to assess how plant-plant interactions influence the resource acquisition and physiological processes of vegetation in natural and afforested P. halepensis woodlands. We also wanted to assess how thinning, one of the most common silvicultural practices, influences the physiology of the remaining trees. Given the potential of isotopic techniques in ecophysiological studies, we wanted to evaluate their utility for investigating plant water use strategies and plant-plant interactions involving water in a semiarid ecosystem of the Iberian SE.

Drylands cover around 41% of Earth’s land surface and include 20% of the major centers of global plant diversity. Drylands are especially vulnerable to climate change and desertification. Maintenance of biodiversity in drylands is crucial to prevent those negative impacts. In order to do so, it is important to understand how dryland plant communities are organized and the processes that allow plant species coexistence in these severely water limited environments. Afforested plantations of Pinus halepensis Mill., that were extensively planted in semiarid areas of the Mediterranean basin during the second half of the XXth century are particularly vulnerable to climate change and drought intensification. The aim of the present PhD thesis was to investigate the water use strategies of some of the most common plant species naturally occurring in the semiarid Iberian SE, and to assess how plant-plant interactions influence the resource acquisition and physiological processes of vegetation in natural and afforested P. halepensis woodlands. We also wanted to assess how thinning, one of the most common silvicultural practices, influences the physiology of the remaining trees. Given the potential of isotopic techniques in ecophysiological studies, we wanted to evaluate their utility for investigating plant water use strategies and plant-plant interactions involving water in a semiarid ecosystem of the Iberian SE.