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Review on fire effects on ectomycorrhizal symbiosis, an unachieved work for a scalding topic
... Consequently, at the early stages (ca. the first 10 years) after fire, most studies showed (i) a decrease in the overall number of fungal species, (ii) shifts in fungal community composition, (iii) an increase in pyrophytic fungal species, and (iv) a decrease in fungal productivity, especially for edible mushroom species yields (Gassibe et al., 2015;Taudière et al., 2017;Salo and Kouki, 2018). Yet, if sufficient time elapses since fire along the secondary succession (i.e., several decades), the fungal community might eventually recover, also in fire-prone ecosystems (Pérez-Varela et al., 2018;Albert-Belda et al., 2023). ...
... Up to date, a variety of fungal responses have been reported along the successional stages following fire, either related to changes in edaphic properties (e.g., soil pH: Orumaa et al., 2022;Martín-Pinto et al., 2023) or to vegetation recovery. Mostly, these responses are taxa-specific (Rincón et al., 2014;Taudière et al., 2017;Enright et al., 2022) or functional guild-specific [i.e., saprotrophic fungi benefited at the initial stages of the post-fire succession, whereas mycorrhizal fungi at the long-term scale (Gassibe et al., 2011(Gassibe et al., , 2015; but see Orumaa et al., 2022). Moreover, fire promotes germination of heat-resistant fungi (Gassibe et al., 2011) that might as well influence soil stabilization (Claridge et al., 2009) and post-fire plant regeneration, particularly in forest ecosystems (Day et al., 2020;Enright et al., 2022). ...
... (2) estimate fungal productivity as a function of the time elapsed since the last fire. We hypothesized that stand-replacing fires will negatively affect fungal productivity, particularly at the early and medium successional stages after fire, and especially in case of edible mushroom species (Gassibe et al., 2015;Taudière et al., 2017;Salo and Kouki, 2018); and (3) analyze which environmental (i.e., vegetation and soil) variables influence the composition of the fungal community at each stage of the post-fire succession. We hypothesized that newly created postfire soil conditions (e.g., pH, nutrient availability, organic matter content) will be the main variables influencing fungal species composition at the different stages following fire (Tedersoo et al., 2020;Orumaa et al., 2022;Martín-Pinto et al., 2023). ...
... Post-fire forests also create new habitats and resources for many polypore fungi (Penttilä et al. 2013;Suominen et al. 2015Suominen et al. , 2018. Fires are also considered a dominant factor in determining the dynamics and diversity of ECM (Taudiere et al. 2017) and SM communities, and high severity fires play an important role in the succession of ECM, pyrophilous saprophytes and aphyllophoroid wood-associated macrofungi (AWAM). Taudiere et al. (2017) recently reviewed 73 field studies that examined the effects of forest fires on ECM symbioses. ...
... Fires are also considered a dominant factor in determining the dynamics and diversity of ECM (Taudiere et al. 2017) and SM communities, and high severity fires play an important role in the succession of ECM, pyrophilous saprophytes and aphyllophoroid wood-associated macrofungi (AWAM). Taudiere et al. (2017) recently reviewed 73 field studies that examined the effects of forest fires on ECM symbioses. The studies were located in boreal (10), Mediterranean (20), temperate (35) and tropical ecosystems (2), and 44 of the publications focused on Pinus-dominated ecosystems. ...
... The studies were located in boreal (10), Mediterranean (20), temperate (35) and tropical ecosystems (2), and 44 of the publications focused on Pinus-dominated ecosystems. Moreover, 20 publications examined the effects of fire (13 wildfires and 7 prescribed burnings) on fungal species richness (Taudiere et al. 2017). The results in regard to the effects of fire on ECM species were ambiguous and included both positive and negative effects. ...
... Various studies have demonstrated both direct and indirect effects of fire on the EMF community while consequently influencing the post-fire regeneration of the plant community (Buscardo et al. 2010;Glassman et al. 2016;Johnson 1995;Marlon et al. 2009;Miller and Urban 1999;Taudière et al. 2017;Veen et al. 2008). Although such effects are expected to be related to fire severity, which often varies during the year, less is known about the specific effect of fire season on the EMF community. ...
... First, we could not detect a significant effect of fire on EMF richness or diversity. This result is in contrast to most studies of prescribed burns, illustrating a negative effect of fire on EMF richness (Taudière et al. 2017). Second, late-dry season (autumn) burns affected EMF community composition, but these differences between the control and autumn (late-dry season) burned plots faded quickly and had disappeared by the next sampling period (Table 1). ...
... We observed the largest differences due to fire season in the total soil fungal community, rather than in the EMF community, and this effect was largely driven by changes within the saprotrophic fungal guild. Most data on fungal response to fire comes from northwestern USA (Taudière et al. 2017), where fires are typically of higher severity than in the eastern Mediterranean basin. Such fires, as those attained in our study, are less likely to lead to host dieback, or to inflict direct damage to soil microorganisms. ...
Fire effects on ecosystems range from destruction of aboveground vegetation to direct and indirect effects on belowground microorganisms. Although variation in such effects is expected to be related to fire severity, another potentially important and poorly understood factor is the effect of fire seasonality on soil microorganisms. We carried out a large-scale field experiment examining the effects of spring (early-dry season) versus autumn (late-dry- season) burns on the community composition of soil fungi in a typical Mediterranean woodland. Although the intensity and severity of our prescribed burns were largely consistent between the two burning seasons, we detected differential fire season effects on the composition of the soil fungal community, driven by changes in the saprotrophic fungal guild. The community composition of ectomycorrhizal fungi, assayed both in pine seedling bioassays and from soil sequencing, appeared to be resilient to the variation inflicted by seasonal fires. Since changes in the soil saprotrophic fungal community can directly influence carbon emission and decomposition rates, we suggest that regardless of their intensity and severity, seasonal fires may cause changes in ecosystem functioning.
... Soil fungi can alter host plant nutrient and water acquisition (Despain, 2001;Smith & Read, 2008) and contribute to ecological functions like carbon and nutrient cycling (Shah et al., 2016). Furthermore, bark beetle outbreaks Pec et al., 2017;Treu et al., 2014), wildfire (Buscardo, Freitas, Pereira, & de Angelis, 2011;Taudière, Richard, & Carcaillet, 2017), logging (Jones, Durall, & Cairney, 2003;Kohout et al., 2018) and salvage logging (Ford, Kleinman, & Hart, 2018;Kutorga et al., 2012) can potentially alter soil fungal communities in coniferous forests. ...
... Environmental conditions important to soil fungi such as soil pH, moisture, nutrients, phenolics and host plant composition can change with disturbance, and thus can alter fungal communities (Goldmann et al., 2015;Kutorga et al., 2012;Pec et al., 2017;Taudière et al., 2017). For example, processes like nutrient cycling differ following MPB outbreak versus wildfire as a result the latter may impose a biotic filter that favours soil fungal communities that respond well to high mineral nutrients in the soil while soil fungal communities following MPB may be better suited to high levels of soil phenolics (Buscardo et al., 2011;Cigan et al., 2015;Pec et al., 2017;Taudière et al., 2017;Treu et al., 2014). ...
... Environmental conditions important to soil fungi such as soil pH, moisture, nutrients, phenolics and host plant composition can change with disturbance, and thus can alter fungal communities (Goldmann et al., 2015;Kutorga et al., 2012;Pec et al., 2017;Taudière et al., 2017). For example, processes like nutrient cycling differ following MPB outbreak versus wildfire as a result the latter may impose a biotic filter that favours soil fungal communities that respond well to high mineral nutrients in the soil while soil fungal communities following MPB may be better suited to high levels of soil phenolics (Buscardo et al., 2011;Cigan et al., 2015;Pec et al., 2017;Taudière et al., 2017;Treu et al., 2014). These changes in soil fungal communities can be critical to lodgepole pine (Karst, Randall, & Gehring, 2014;Pec et al., 2017;Smith, Douhan, Fremier, & Rizzo, 2009;Treu et al., 2014) and have cascading impacts on pine seedling biomass and secondary chemical production . ...
Disturbances are frequent events across the Canadian boreal forest and can affect both below‐ and above‐ground ecosystem processes. How disturbances change below‐ground soil fungal communities and in‐turn affect pine establishment and performance is poorly understood. Such understanding has become increasingly important in light of observed changes in disturbance regimes in recent years due to climate change.
We used a greenhouse experiment to determine how soil inoculum collected from lodgepole pine stands undisturbed (control) or disturbed by fire, mountain pine beetle outbreak, logging and salvage logging affect pine seedling performance in western Canada. We first characterized whether fungal communities of seedling roots change as a function of inoculum source, and then determined whether changes in fungal community composition impact pine seedling performance (biomass and height).
Root fungal communities of pine seedlings from logged and salvage logged disturbances differed from their respective paired controls, while soils from natural disturbances (fire and beetle outbreak) did not. Among disturbances, the pine root fungal communities of fire and salvage logged disturbances differed.
In parallel to the root fungal communities, seedling performance also decreased when comparing logging and salvage logging disturbances to paired controls. Among disturbance treatments, seedlings from the salvage logged disturbance did not grow as big as seedlings inoculated with soils from burned forests.
Synthesis and application. Our findings indicate that anthropogenic disturbances (logging and salvage logging) can have cross‐generational impacts on pine seedling performance, through functional shifts in seedling root fungal community structure. Furthermore, the impacts of soil fungi on pine seedlings appear to be pronounced following salvage logging, stressing the importance of compound disturbance events. These findings may be important to land managers considering clear‐cut logging or salvage logging in pine forests, particularly where soil biotic communities are likely to be one of the predominate factors in pine establishment.
... Moreover, ECM fungi have recently been shown to be also able to transfer substantial amount of carbon into forest soils, for long-term storage (Clemmensen et al., 2013), and consequently affect key ecosystem properties. While intensive, clear-cut harvesting is known to seriously reduce ECM fungi (Kohout et al., 2018;Parladé et al., 2019;Sterkenburg et al., 2019), the role of fire appears to be much more variable (Taudière et al., 2017;Salo and Kouki, 2018). ...
... Most of the more recent studies have explored ECM and WAM fungi, particularly aphyllophoroid species. Fires often reduce the amount of fungi in these groups, but the overall effects are still hard to identify (Taudière et al., 2017). ...
... In burned and unharvested sites, the diversity and biomass of ECM species did not systematically differ from unburned control sites. Previous studies on ECM and fire have provided contrasting results (reviewed by Taudière et al., 2017). ...
... Mycorrhizal fungi are common mutualists of land plants that influence ecosystems through their roles in productivity and nutrient cycles (Smith and Read 2010). Since biological function is often closely associated with community composition (Forrester and Bauhus 2016;Maciá-Vicente et al. 2023), studying the processes that influence mycorrhizal community assembly can improve our understanding of mycorrhizal ecology and responses to environmental change. ...
... Six months after Fall fires, fire affected community assembly through changes in sporulation (higher), spore volume (lower), and color saturation (less color rich pigmentation). Sporulation allows fungi to survive stressful conditions (Peay et al. 2009;Taudière et al. 2017), and pigmentation can provide protection against high temperatures and harmful reactive oxygen species (Gessler et al. 2014;Rajamani et al. 2021), while smaller spore volumes can help prevent heat transfer during fire (Bejan and Kraus 2003). This suggests that fire-associated changes to the soil environment like increased UV exposure, soil heating, and oxidative stress drove the observed changes in community assembly (Certini 2005;Pereira et al. 2018;Magaña-Hernández et al. 2020;Sigmund et al. 2021). ...
Background and aims
Arbuscular mycorrhizal (AM) fungi are common mutualists in grassland and savanna systems that are adapted to recurrent fire disturbance. This long-term adaptation to fire means that AM fungi display disturbance associated traits which should be useful for understanding environmental and seasonal effects on AM fungal community assembly.
Methods
In this work, we evaluated how fire effects on AM fungal spore traits and community composition vary with fire season (Fall vs. Spring) and time since fire. We tested this by analyzing AM fungal spore traits (e.g., colorimetric, sporulation, and size) from a fire regime experiment.
Results
Immediately following Fall and Spring fires, spore pigmentation darkened (became less hyaline); however, this trait response was not linked to fire driven changes in spore community composition and likely implies a plastic spore pigmentation response to fire. Six months after Fall fires, spores in burned plots were lower in volume, produced less color rich pigment, and had higher sporulation rates, and these differences in spore traits were associated with shifts in AM fungal spore communities demonstrating environmental filtering.
Conclusion
Fire drove plastic and longer-term changes in AM fungal spore traits and community assembly that varied with fire season (stronger effects in Fall) and time since fire. This demonstrates the utility of applying trait-based approaches to microbial community assembly, and the importance of considering changes in community assembly across time.
... However, despite their critical role in driving aboveground recovery after fire, the temporal dynamics of fungal responses to fire are poorly documented at finer taxonomic scales (e.g. with regard to fungi that vary in ectomycorrhizal exploration strategies, trophic guilds, 'inter-guild' associations;Twieg et al., 2007;Visser, 1995). This knowledge is especially limited in some ecosystems such as Australian eucalypt forests (Ammitzboll et al., 2021;Bowd et al., 2022a;Taudière et al., 2017; for comparisons of logging versus burning). Despite this, fire-prone eucalypt forests occur over 100 million hectares in Australia (ABARES, 2018) and are dominated by vegetation with ectomycorrhizal associations (Brundrett & Tedersoo, 2018), which facilitate tree growth, resilience and survival across many nutrient-limited ecosystems (Policelli et al., 2020;Scott et al., 2013). ...
... Despite this, fire-prone eucalypt forests occur over 100 million hectares in Australia (ABARES, 2018) and are dominated by vegetation with ectomycorrhizal associations (Brundrett & Tedersoo, 2018), which facilitate tree growth, resilience and survival across many nutrient-limited ecosystems (Policelli et al., 2020;Scott et al., 2013). Given their critical role in facilitating postfire recovery, understanding how fungal communities respond to fire over time in these and other ecosystems is important, not only for forest conservation but also for understanding about the maintenance of key ecological functions, and for future management and planning (McMullan-Fisher et al., 2002;Taudière et al., 2017;Visser, 1995). ...
Fire is a major evolutionary and ecological driver that shapes biodiversity in forests. While above-ground community responses to fire have been well-documented, those below-ground are much less understood. However, below-ground communities, including fungi, play key roles in forests and facilitate the recovery of other organisms after fire. Here, we used internal transcribed spacer (ITS) meta-barcoding data from forests with three different times since fire [short (3 years), medium (13-19 years) and long (>26 years)] to characterize the temporal responses of soil fungal communities across functional groups, ectomycorrhizal exploration strategies and inter-guild associations. Our findings indicate that fire effects on fungal communities are strongest in the short to medium term, with clear distinctions between communities in forests with a short time (3 years) since fire, a medium time (13-19 years) and a long time (>26 years) since fire. Ectomycorrhizal fungi were disproportionately impacted by fire relative to saprotrophs, but the direction of the response varied depending on morphological structures and exploration strategies. For instance, short-distance ectomycorrhizal fungi increased with recent fire, while medium-distance (fringe) ectomycorrhizal fungi decreased. Further, we detected strong, negative inter-guild associations between ectomycorrhizal and saprotrophic fungi but only at medium and long times since fire. Given the functional significance of fungi, the temporal changes in fungal composition, inter-guild associations and functional groups after fire demonstrated in our study may have functional implications that require adaptive management to curtail.
... Wildfire affects soil microorganisms [15][16][17], including fungi [6,18,19], due to changes in soil properties or partner plants [20,21]. Soil biological properties would be more sensitive to disturbances than physical and chemical ones, and their response should be faster and broader [22]. ...
... Su et al. [96] focused on a period of three decades after a fire to measure its effects. Since the method and the strategy to assess fungal communities is crucial [19], the present result should be considered with caution. However, we can predict that the biodiversity of AMF is expected to decrease in the near future when a fire has occurred twice in a short interval because (i) AMF has a mutualistic relationship with herbs, whose biodiversity decreased immediately, (ii) AMF recycles the SOM that has dropped, and (iii) because the soil biological properties were depleted. ...
The semi-arid forest ecosystems of western Iran dominated by Quercus brantii are often disturbed by wildfires. Here, we assessed the effects of short fire intervals on the soil properties and community diversity of herbaceous plants and arbuscular mycorrhizal fungi (AMF), as well as the interactions between these ecosystem features. Plots burned once or twice within 10 years were compared to unburned plots over a long time period (control sites). Soil physical properties were not affected by the short fire interval, except bulk density, which increased. Soil geochemical and biological properties were affected by the fires. Soil organic matter and nitrogen concentrations were depleted by two fires. Short intervals impaired microbial respiration, microbial biomass carbon, substrate-induced respiration, and urease enzyme activity. The successive fires affected the AMF's Shannon diversity. The diversity of the herb community increased after one fire and dropped after two, indicating that the whole community structure was altered. Two fires had greater direct than indirect effects on plant and fungal diversity, as well as soil properties. Short-interval fires depleted soil functional properties and reduced herb diversity. With short-interval fires probably fostered by anthropogenic climate change, the functionalities of this semi-arid oak forest could collapse, necessitating fire mitigation.
... Incidence of damping-off can increase with pH in forest nursery soils (Kacprzak et al., 2001) and has been shown to cause >25% seedling losses in lodgepole pine seedlings above pH 7.0 (Griffin, 1958). Soil heating influences the composition of soil microbes and can reduce tree root symbionts after wildfire (Douglas et al., 2005;Martín-Pinto et al., 2006;Twieg et al., 2009;Glassman et al., 2016), pile burning (Pilz and Perry, 1984;Korb et al., 2004;Jiménez-Esquilín et al., 2007) and prescribed broadcast burning (Herr et al., 1994;Stendell et al., 1999;Taudière et al., 2017). However, the magnitude and duration of these effects vary with fire severity, forest types and site characteristics (Cairney and Bastias, 2007;Taudière et al., 2017). ...
... Soil heating influences the composition of soil microbes and can reduce tree root symbionts after wildfire (Douglas et al., 2005;Martín-Pinto et al., 2006;Twieg et al., 2009;Glassman et al., 2016), pile burning (Pilz and Perry, 1984;Korb et al., 2004;Jiménez-Esquilín et al., 2007) and prescribed broadcast burning (Herr et al., 1994;Stendell et al., 1999;Taudière et al., 2017). However, the magnitude and duration of these effects vary with fire severity, forest types and site characteristics (Cairney and Bastias, 2007;Taudière et al., 2017). For example, pile burning eliminated most arbuscular mycorrhizal symbionts and native plant seeds from ponderosa pine forest soils (Korb et al., 2004;Jiménez-Esquilín et al., 2007). ...
Pile burning is the most common method of logging residue disposal in Rocky Mountain forests. Though the high temperatures reached during burning affect numerous soil properties in the short term, the longer-term effects of the practice are less clear. We previously identified a 50-year time series of burn scars created after clear cut harvesting in lodgepole pine stands where we reported sparse tree colonization across the entire chronosequence. Here we analyzed soil nutrients and chemistry and conducted in situ and greenhouse seedling bioassays to determine whether edaphic factors or poor seedling performance explain the pattern. Pile burning had a lasting effect on soil pH, but nutrient availability was 2-3 times higher in burn scars compared to unburned forest soils for many constituents and planted pine seedlings had good survival and growth. However, seedling growth was slightly less in burn scars compared to unburned soils indicating suboptimal soil pH or other belowground factors may contribute to sparse tree colonization of the openings. For example, seedling survival and ectomycorrhizal fungi colonization were both lowest in the most recently created scars where soils were alkaline and improved with time as pH declined, suggesting gradual amelioration of post-fire growing conditions. Survival in burn scars was comparable for unprotected trees and those in protective mesh tubes, indicating that herbivory was not a significant impediment to seedling establishment. However, a preliminary study suggests that seed predation may have contributed to the low tree colonization into the openings. Though large burn pile scars may require soil rehabilitation, and soil changes may have a lasting effect on understory plant composition, we found that they were not a significant barrier to tree establishment in these moderate-size burn scars.
... The frequency of wildfires will also be expected to increase in this area through the association with lower than average quantity of precipitation and longer dry periods (Veble and Brečko Grubar, 2016). Drought stress may affect the structure of ECM communities or the abundance of individual taxa (Richard et al., 2011;Mrak et al., 2019) and wildfires have been reported either to cause reduction in diversity/richness of ECM fungi or have no impact, while decreased colonization of roots following wildfire by ECM fungi was confirmed by numerous studies (Taudiere et al., 2017). While Q. pubescens within this area is wellstudied, the temporal dynamics of their associated ECM fungi are not. ...
... Along with heat effects, wildfires impact carbon and nitrogen cycling and soil pH through the inputs of organic matter in the form of ash and charcoal into the soil system. Wildfires also result in the elimination of the soil organic layer and partial heat-sterilization of soil (Buscardo et al., 2010;Taudiere et al., 2017). ...
Temporal studies that would offer insight into resilience of ectomycorrhizal (ECM) communities in stress prone climates are scarce despite their role in tree nutrition and water supply. Our study characterized the vitality, community composition, diversity, and function of Quercus pubescens Willd. ECM fungi in the Sub-Mediterranean stress-prone environment for 2 consecutive years (June 2016–May 2018) and related the investigated measures to environmental parameters. ECM community was assessed for species actively associating with root tips and exploring the soil volume through the assessment of mycelial ingrowth into sand-filled mesh bags. The investigated period was characterized by a drier than average summer combined with wildfire in 2016 followed by another dry summer in 2017. The vital to non-vital ECM root tip ratio decreased below one in August 2016 and remained low until January 2018. This was ascribed to a series of stress events that occurred at the site including sequential droughts and wildfire. The most abundant ECM lineages on root tips were Tomentella and other Thelephoraceae, Sebacina, and Cenococcum while in mesh bags the most abundant were Tomentella, Sebacina, Pseudotomentella, Pyronemataceae, Inocybe, Cortinarius, Agaricales, and Boletales lineages. High intra-site variability was observed, with ECM communities directly associated with root tips and exploring the soil volume varying significantly among the plots. Community composition was stable over time, while species richness varied with mean air and soil temperature, relative air humidity, and solar radiation. The most abundant exploration type observed at this site was short distance, which was associated with precipitation along with long distance exploration type. The medium distance exploration type was temporally variable and responded to soil temperature and relative air humidity reflecting seasonality at the site. The presented results indicate complex relationships between environmental parameters, abiotic stress, and ECM fungi.
... In addition, further studies are required to increase our understanding of the dynamics of soil fungi and their community structure (Dhruba et al., 2015) and the impact of various environmental and anthropogenic factors. Furthermore, to date, most studies of soil fungal communities have focussed on temperate and Mediterranean forest ecosystems; less consideration has been given to soil fungal communities in tropical forest ecosystems (Taudière et al., 2017). ...
... However, the inconsistency of results from individual studies makes it difficult to provide a general conclusion regarding the possible dynamics of fire, fungi and ecosystem function. Consequently, location-based studies are necessary to obtain a better understanding of the effect of fire on the soil fungal community at a specific location (Taudière et al., 2017). ...
Ethiopian dry Afromontane forests are complex ecosystems that have important economic and ecological roles. However, recurrent fire has been a source of disturbance for these forests. We assessed the effect of fire on soil fungal communities in a remnant dry Afromontane forest in Wondo Genet, southern Ethiopia, by analysing soil samples collected from unburned stands and from stands one and ten years after fire using DNA metabarcoding of the ITS2 rDNA. The analysis indicated that the soil fungal community was most diverse soon after a fire disturbance and declined over time. Fungal community composition also differed among stands. Our results also indicated that differences in fungal diversity were stand dependent rather than due to the chronology of the fire history in this forest system. We found higher numbers of mycorrhizal species in burned stands, suggesting that these fungal symbionts could compensate for the effects of nutrient stress caused by fire in these areas. Fungal community composition was also significantly correlated with organic matter content, potassium and magnesium in soil. This work could be considered as a case study since the plots were established in a single stand for each treatment in the dry Afromontane forests of Ethiopia. Thus, we recommend further studies and conclusions regarding other stands need to be taken with caution.
... Wilhelm et al. (2017) found that soil fungal communities had long-term responses to clearcutting for decades after harvest; the relative abundances of drought-tolerant and heat-tolerant taxa increased, while EcM fungal diversity decreased. Nevertheless, comprehensive studies on soil fungal succession in wildfire chronosequences are relatively limited (Cairney & Bastias, 2007;McMullan-Fisher et al., 2011;Taudiere et al., 2017), especially in East Asia. Existing studies suggest that, in the short-term (e.g. ...
... Changes in community composition are the most frequently observed effect of wildfire on soil fungi (McMullan-Fisher et al., 2011;Taudiere et al., 2017). In this study, burning effects on fungal composition (including EcM fungi and saprotrophs) were pronounced in upper soils (Fig. 3). ...
Soil fungi represent a major component of below‐ground biodiversity that determines the succession and recovery of forests after disturbance. However, their successional trajectories and driving mechanisms following wildfire remain unclear.
We examined fungal biomass, richness, composition and enzymes across three soil horizons (Oe, A1 and A2) along a near‐complete fire chronosequence (1, 2, 8, 14, 30, 49 and c. 260 yr) in cold‐temperate forests of the Great Khingan Mountains, China. The importance of soil properties, spatial distance and tree composition were also tested.
Ectomycorrhizal fungal richness and β‐glucosidase activity were strongly reduced by burning and significantly increased with ‘time since fire’ in the Oe horizon but not in the mineral horizons. Time since fire and soil C : N ratio were the primary drivers of fungal composition in the Oe and A1/A2 horizons, respectively. Ectomycorrhizal fungal composition was remarkably sensitive to fire history in the Oe horizon, while saprotroph community was strongly affected by time since fire in the deeper soil horizon and this effect emerged 18 years after fire in the A2 horizon.
Our study demonstrates pronounced horizon‐dependent successional trajectories following wildfire and indicates interactive effects of time since fire, soil stoichiometry and spatial distance in the reassembly of below‐ground fungal communities in a cold and fire‐prone region.
... Microorganisms and fungi are affected due to changes in soil properties and vegetation after fire (Dove & Hart, 2017;Lombao et al., 2021;Mirzaei et al., 2023;Nelson et al., 2022;Owen et al., 2019;Taudière et al., 2017). Microorganisms uppermost soil layer in burnt rangelands are sensitive to temperature and fire. ...
This study explored whether wildfire alters the soil properties and arbuscular mycorrhizal fungi (AMF) community composition when compared with burnt rangeland, non-burnt rangeland and adjacent tilled in mesothermal ecosystems. The study was carried out in August 2020, 1 year later after wildfire. The results of this study showed that the wildfire played a key role in altering soil characteristics and AMF community composition in Bartin Province located in the Western Black Sea Region. Soil samples were made according to standard methods. AMF spores were isolated according to the wet sieving method, and the spores of AMF were identified according to their morphological characteristics. Analysis of variance was performed to determine the differences between the parameters, and correlation analysis was performed to determine the relationships between the parameters. The highest values of soil organic carbon (2.20%), total nitrogen (0.18%), K2O (74.68 kg/da), root colonization (87.5%) and the frequency of occurrence of Funneliformis geosporum (20%), Claroideoglomus claroideum (16%) and Claroideoglomus etunicatum (11%) were found in burnt rangeland. Sporulation of Acaulospora dilatata, Acaulospora morrowiae, Acaulospora tuberculata, Scutellospora castanea, Scutellospora coralloidea, Scutellospora scutata, Glomus coremioides and Glomus multicaule was either decreased or completely inhibited in the burnt rangeland. While species diversity of AMF (12) decreased, the number of AMF spores (325.6 (number/50 gr soil)) increased in burnt areas. In conclusion, the number of spores and root colonization of AMF increased but species diversity of AMF reduced after the wildfire. In ecosystems with high fire risk where AMF transfer is planned, it is suggested that it would be more appropriate to select species with an increase in spore number after fire.
... However, in the long term, a decrease in the bacterial and fungal diversity was found 14 years after a wildfire (Huffman and Madritch, 2018). Long-term shifts in the composition of ectomycorrhizal fungal communities have been observed after wildfires and prescribed fires (Taudière et al., 2017). The fire impact on soil and the following postfire recovery of the microbiota can differ depending on the fire recurrence. ...
Bush burning, whether the result of a wildfire or a controlled burn, has been shown to affect not only the appearance of the landscape, but the quality of the soil as well. Uncontrolled bush fires impact the soil in a variety of ways with the magnitude of the disturbance largely dependent upon the fire intensity, duration and recurrence, fuel load, and soil characteristics. The impact on soil properties is intricate, yielding different results based on these factors. Whereas burning off the vegetation during land clearing for cultivation is a common farming practice among farmers in many parts of the tropics, yet little is known by perpetrators of this practice about its impacts on the soil and its dwellers. This paper reviews research findings from a number of works conducted across the globe with the aim of gaining an insight the effects of wildfire and prescribed fire on the soil chemical and biological attributes. The knowledge of soils response in terms of these two properties to fire events can help in proper implementation of rehabilitation and restoration strategies at the short term, medium term, and long term.
... Since fire kills plant-associated pathogens (Mooney and Conrad 1977;Katan 2000;Beals et al. 2022), fire may reduce or neutralize negative feedbacks. If fire kills mutualists like mycorrhizal fungi or rhizobia however (severe fire in particular; Klopatek et al. 1988;Taudière et al. 2017;Hewitt et al. 2022), then this could reduce the strength of positive feedbacks. ...
Background and aims
Plant soil feedbacks (PSF) are reciprocal mechanisms through which interactions between plants and soil biota and affect future plant growth. When scaled up to the community level, PSFs are important determinants of above- and belowground community dynamics that influence long-term successional trajectories. Despite over three decades of ecological PSF research, we have a poor understanding of how common environmental processes like fire influence the strength and direction of PSFs. The aim of this study was to evaluate fire effects on PSFs between two common grassland species: Schizachyrium scoparium and Rudbeckia hirta.
Methods
In this work we evaluated how fire effects on S. scoparium and R. hirta associated soil biota influenced feedbacks on plant growth using a two phase experiment. We tested this by first growing S. scoparium and R. hirta with the same soil inocula, and then simulating low intensity, grassland fires in a controlled greenhouse pot experiment (soil training). We then evaluated plant growth responses to burned and unburned inter- and intraspecific soil biota treatments (response phase).
Results
Fire effects on inocula neutralized negative feedbacks in S. scoparium, and caused negative feedbacks in R. hirta. This shows that environmental disturbance like fire can alter the strength and direction of PSFs in ways that modify plant growth and potentially influence plant fuel loads and community dynamics.
Conclusion
That fire can alter the strength and direction of PSFs on plant growth suggests that fire effects on soil related processes may influence plant community dynamics and fire-fuel dynamics in fire recurrent grassland ecosystems. Further, this study shows that fire effects on PSFs vary between plant species.
... Over small and large spatial scales, biological responses to re contribute to changes in diversity ( Beals et al. 2022), re may reduce or neutralize negative feedbacks. If re kills mutualists like mycorrhizal fungi or rhizobia however (severe re in particular; Klopatek et al. 1988;Taudière et al. 2017;Hewitt et al. 2022), then this could reduce the strength of positive feedbacks. Therefore, any re associated changes to PSFs (particularly negative PSFs) could alter the dominance of plant taxa, reduce diversity, change plant fuel loads, and facilitate invasion by re tolerant plant species (Brooks 2002 effects on PSFs can help us understand the processes that structure above-and belowground communities and re-fuel feedbacks of re frequented ecosystems. ...
Background and aims
Plant soil feedbacks (PSF) are reciprocal mechanisms through which plants modify soil biota and affect future plant growth. When scaled up to the community level, PSFs are important determinants of above- and belowground community dynamics that influence long-term successional trajectories. Despite over three decades of ecological PSF research, we have a poor understanding of how common environmental processes like fire influence the strength and direction of PSFs.
Methods
In this work we evaluated how fire effects on Schizachyrium scoparium and Rudbeckia hirta trained soil biota influenced feedbacks on plant growth. We tested this by experimentally manipulating fires and evaluating plant growth responses to burned and unburned inter- and intraspecific soil biota treatments.
Results
Fire effects on inocula neutralized negative feedbacks in S. scoparium, and caused negative feedbacks in R. hirta. This shows that environmental disturbance like fire can alter the strength and direction of PSFs in ways that potentially modify plant growth, plant fuel loads, and community dynamics.
Conclusion
That fire can alter the strength and direction of PSFs on plant growth suggests that fire effects on soil related processes contribute to plant community assembly and fire-fuel dynamics in fire recurrent grassland and savanna ecosystems. Further, this study shows that fire effects on PSFs vary between plant species, and may contribute to the dominance of C4 grasses in pyrophilic ecosystems.
... In all three soil horizons, fungi assigned to the EcM genus Russula were the most abundant indicators for the most frequent fire treatment (T1). Several studies have indicated Russula spp. to be fire responsive, or more abundant following fire (Taudière et al., 2017;Salo and Kouki, 2018;Rasmussen et al., 2018;Oliver, 2020;Dove et al., 2021), whereas others reported Russula spp. to decrease in abundance following fire, and are therefore fire sensitive (Dove et al., 2021;Pérez-Izquierdo et al., 2021). These results support our hypothesis that in the more frequent fire-interval treatments, we do indeed see enrichment of putative pyrophilic taxa. ...
Prescribed fires are common in forest management, yet we lack a clear picture of how different fire frequencies impact soil systems. Here, we present evidence of microbial community and soil chemistry shifts following sixty years of continuous prescribed fire interval manipulation at the Olustee Experimental Forest in Northeastern Florida. We investigated three fire interval treatments (1 year, 2 years, and 4 years) in addition to an unburned control treatment. We sampled three mineral soil horizons (A, E, and Bh) to elucidate prescribed fire impacts across the soil profile. Our results indicate that only the A horizon was affected by the fire interval manipulations, whereas the deeper E and Bh horizons were minimally impacted. Richness of both bacterial and fungal communities in recurring fire treatments was higher than, and their community composition different from, those in the unburned control in A horizon soils. Similar to the biotic soil attributes, fire interval treatments altered soil chemistry only in the topmost A horizon: the burned treatments had higher total nitrogen, total carbon, phosphorus, and NH 4 + than the fire exclusion treatment; the soil chemistry of the deeper E and Bh horizons did not differ among the treatments. All soil chemistry properties correlated with bacterial community composition of the A horizon and nearly all properties correlated with fungal community composition of the A horizon as well, especially when comparing the more frequent burns to the fire exclusion treatment. Indicator taxon analyses identified fire-responsive bacteria and fungi, such as Ktedonobacteria sp. and an unclassified ascomycete that were abundant in the fire exclusion treatment and the ectomycorrhizal Russula spp. that were most abundant in the annual burn treatment. The different fire intervals also impacted fungal guilds, suggesting shifts in community function. The fire exclusion treatment was enriched with ectomycorrhizal, lichenized, and wood saprotrophic fungi, whereas the annual burn treatment was enriched with arbuscular mycorrhizal fungi compared to the other treatments. Our results indicate that long-term changes in the type and amount of detrital inputs and changes in the plant community associated with differing fire frequencies can induce shifts in the soil microbial community.
... High severity fires reduce microbial biomass (Dooley and Treseder, 2012), richness (Pressler et al., 2019), and alter community composition by promoting pyrophilous fire specialists (Seaver, 1909;Enright et al., 2022;Fox et al., 2022) at the expense of other microbial taxa with less tolerance of post-fire conditions. Studies examining the effect of fire on mycorrhizal fungal richness at the local scale exhibit contrasting results (Taudière et al., 2017). However, wildfires generally reduce root colonization (Dove and Hart, 2017) and change community structure (Glassman et al., 2016;Owen et al., 2019). ...
Lodgepole pine forests are under threat due to wildfires of increasing severity and frequency coupled with tree mortality from insect outbreaks. Soil microbial communities, which drive biogeochemical cycles and partner in mycorrhizal symbiosis with lodgepole pines, play critical roles in the ability of these forests to survive and regenerate in the face of simultaneous global change threats. How soil microbial communities are influenced by fire severity and soil depth and how they recover over time in lodgepole pine forests with existing insect-driven mortality remains an open question. Here, we sampled two soil depths (0-5 and 5-15 cm) and various burn severities across a ten-year wildfire chronosequence in the Southern Rocky Mountains. We used qPCR of 18S and 16S rRNA genes to assess changes in fungal and bacterial abundance and ITS2 and 16S amplicon sequencing to assess fungal and bacterial richness and composition. Our results show that: 1) higher severity fires led to larger reductions of both fungal and bacterial abundance and richness, 2) the impact of fire on fungal and bacterial communities was modulated by soil depth, with more severe impacts in shallower soils 3) both fungal and bacterial communities exhibit a partial recovery of abundance and species richness in older fires, 4) fire severity is the main driver of fungal and bacterial community structure but its effect varied across time, 5) pyrophilous "fire-loving" fungi and bacteria exhibit an increased abundance in burned plots, particularly in recent fires, and 6) symbiotic ectomycorrhizal fungi are particularly hard hit by the compound effect of the beetle-driven tree mortality and wildfires. They exhibit a consistently low abundance and richness in the high severity plots which did not recover over time, and unburned plots have a depauperated ectomycorrhizal community.
... However, prescribed burning, which is typically less intense and less severe than a wildfire event, is generally expected to have less impact on the soil fungal community than wildfire (Oliver et al., 2015;Hart et al., 2018;Giuditta et al., 2019;V azquez-Veloso et al., 2022). In this sense, different responses have been reported in soil fungal communities in high forests and shrublands after low-severity experimental fires, ranging from a decrease in diversity and sporocarp production levels (Martín-Pinto et al., 2006;Taudi ere et al., 2017), to no effect (Oliver et al., 2015;V azquez-Veloso et al., 2022) to a slight increase when compared with the effect of other forest management methods (Hern andez- Rodríguez et al., 2013). ...
Background: More than a decade of fire suppression has changed the structure of fire-adapted shrubland ecosystems in Spain's National Parks, which are now at extreme risk of uncontrolled wildfires. Prescribed burning can mitigate the risk of wildfires by reducing the fuel load but prescribed burning may also alter the soil properties and reduce microbial and fungal activity, causing changes in the availability of nutrients deep in the soil layer. Although fungal communities are a vital part of post-fire restoration, some fire effects remain unclear. To examine the short-term effects of prescribed burning on soil fungal communities in Doñana Biological Reserve (SW Spain), we collected soil samples pre-burn and 1 day, 6 and 12 months post-burn from burned plots to perform physicochemical and metabarcode DNA analyses. Results: Prescribed burning had no significant effect on the total fungal operational taxonomic unit richness and abundance. However, changes in soil pH, nitrogen and potassium content post-burn affected fungal community composition. Small non-significant changes in pH and phosphorous affected the composition of ectomycorrhizal fungi. Conclusions: The ectomycorrhizal fungal community appears to be resilient to the effects of low-to moderate-intensity fires and saprotrophic taxa may benefit from this kind of fire. This finding revealed that prescribed burning is a potentially valuable management tool for reducing fire hazards in shrublands that has little effect on the total richness and abundance of fungal communities.
... High severity fires reduce microbial biomass (Dooley and Treseder, 2012), richness (Pressler et al., 2019), and alter community composition by promoting pyrophilous fire specialists (Seaver, 1909;Enright et al., 2022;Fox et al., 2022) at the expense of other microbial taxa with less tolerance of post-fire conditions. Studies examining the effect of fire on mycorrhizal fungal richness at the local scale exhibit contrasting results (Taudière et al., 2017). However, wildfires generally reduce root colonization (Dove and Hart, 2017) and change community structure (Glassman et al., 2016;Owen et al., 2019). ...
... However, such results have yet to be placed in a PSF framework to more clearly understand communitylevel effects. For example, fire can lead to the death and modified community composition of ectomycorrhizal fungi (Glassman et al. 2016, Taudière et al. 2017, which are well known to be positive mutualists for plants. Such a result could lead to a potential shift towards a net negative PSF if pathogens are then more relatively abundant. ...
Although plant–soil feedbacks (interactions between plants and soils, often mediated by soil microbes, abbreviated as PSFs) are widely known to influence patterns of plant diversity at local and landscape scales, these interactions are rarely examined in the context of important environmental factors. Resolving the roles of environmental factors is important because the environmental context may alter PSF patterns by modifying the strength or even direction of PSFs for certain species. One important environmental factor that is increasing in scale and frequency with climate change is fire, though the influence of fire on PSFs remains essentially unexamined. By changing microbial community composition, fire may alter the microbes available to colonize the roots of plants and thus seedling growth post‐fire. This has potential to change the strength and/or direction of PSFs, depending on how such changes in microbial community composition occur and the plant species with which the microbes interact. We examined how a recent fire altered PSFs of two leguminous, nitrogen‐fixing tree species in Hawaiʻi. For both species, growing in conspecific soil resulted in higher plant performance (as measured by biomass production) than growing in heterospecific soil. This pattern was mediated by nodule formation, an important process for growth for legume species. Fire weakened PSFs for these species and therefore pairwise PSFs, which were significant in unburned soils, but were nonsignificant in burned soils. Theory suggests that positive PSFs such as those found in unburned sites would reinforce the dominance of species where they are locally dominant. The change in pairwise PSFs with burn status shows PSF‐mediated dominance might diminish after fire. Our results demonstrate that fire can modify PSFs by weakening the legume‐rhizobia symbiosis, which may alter local competitive dynamics between two canopy dominant tree species. These findings illustrate the importance of considering environmental context when evaluating the role of PSFs for plants.
... The effect of fire on ECMF communities is an active field of research that has variable consensus. There is good evidence that fire shifts ECMF composition for long (∼50 year) timeframes and moderate evidence that fire reduces diversity and inoculum potential (measured with colonization) over decadal timeframes (∼22 and 11 years, respectively) Dove and Hart, 2017;Taudière et al., 2017). We also know there is a suite of fungi, termed the "ectomycorrhizal fungal sporebank, " that is separate and compositionally distinct from the active ECMF community and exists in the soil as resistant propagules that colonize regenerating plant hosts post-disturbance (Glassman et al., 2015(Glassman et al., , 2016; in WBP forests, this community is dominated by Rhizopogon, Cenococcum, Wilcoxina and Thelephora (Glassman et al., 2015). ...
Whitebark pine ( Pinus albicaulis Engelm.; WBP) is an endangered subalpine tree species and requires associations with ectomycorrhizal fungi (ECMF) for survival and growth. Despite this obligate dependence, there are gaps in the identification of ECMF that associate with WBP. In addition, ECMF rarely feature in assessments of recovery actions and little is known about the relationship between ECMF and the insects and pathogens affecting WBP. We used next-generation sequencing to characterize ECMF occurring in soil and mycorrhizal root tip samples from naturally occurring mature WBP trees and seedlings as well as planted WBP seedlings in the Columbia Mountains of Interior British Columbia, Canada. ECMF data was paired with data on tree age, tree health and soil conditions. Thirty-three species and twenty-one genera of ECMF were identified with medium or high confidence from mycorrhizal root tip samples. Major groups were: generalist ascomycetes [ Cenococcum , Meliniomyces (= Hyaloscypha )], Atheliales ( Piloderma, Amphinema, Tylospora ), non-ascomycetous generalists (e.g., Amphinema ), associates of high-elevation conifers (species of Cortinarius, Russula ) and Suilloids ( Suillus, Rhizopogon ). Differences in WBP ECMF with other, drier and southerly regions that have been studied previously, were consistent with a distinct forest type and an endemism hypothesis. Soil at the planting site and planted seedlings hosted a reduced ECMF community or were non-ectomycorrhizal, which can be explained by site factors and is expected to affect seedling survival. ECMF composition on mature trees was correlated with tree health, which may have implications for WBPs resistance to pathogens and signals that ECMF are affected by the decline of their host. Understanding the ecology of WBP ECMF and their relationship with tree performance is essential for WBP recovery efforts.
... For instance, it is known that soil heating increases the predominance of soil bacteria while reducing the fungal abundance (Fultz et al., 2016;Rutigliano et al., 2007). In a review by Taudière et al. (2017), negative effects of prescribed fires on ectomycorrhizal (ECM) fungal richness are reported, but the authors acknowledge that further studies are necessary to understand how this practice could impact ECM fungal diversity. Furthermore, Tomao et al. (2020) shows that there is not much consistency in the literature on the effect of prescribed burning on fungal species diversity. ...
The global forest carbon (C) stock is estimated at 662 Gt of which 45% is in soil organic matter. Thus, comprehensive understanding of the effects of forest management practices on forest soil C stock and greenhouse gas (GHG) fluxes is needed for the development of effective forest-based climate change mitigation strategies. To improve this understanding, we synthesized peer-reviewed literature on forest management practices that can mitigate climate change by increasing soil C stocks and reducing GHG emissions. We further identified soil processes that affect soil GHG balance and discussed how models represent forest management effects on soil in GHG inventories and scenario analyses to address forest climate change mitigation potential.
Forest management effects depend strongly on the specific practice and land type. Intensive timber harvesting with removal of harvest residues/stumps results in a reduction in soil C stock, while high stocking density and enhanced productivity by fertilization or dominance of coniferous species increase soil C stock. Nitrogen fertilization increases the soil C stock and N2O emissions while decreasing the CH4 sink. Peatland hydrology management is a major driver of the GHG emissions of the peatland forests, with lower water level corresponding to higher CO2 emissions. Furthermore, the global warming potential of all GHG emissions (CO2, CH4 and N2O) together can be ten-fold higher after clear-cutting than in peatlands with standing trees.
The climate change mitigation potential of forest soils, as estimated by modelling approaches, accounts for stand biomass driven effects and climate factors that affect the decomposition rate. A future challenge is to account for the effects of soil preparation and other management that affects soil processes by changing soil temperature, soil moisture, soil nutrient balance, microbial community structure and processes, hydrology and soil oxygen concentration in the models. We recommend that soil monitoring and modelling focus on linking processes of soil C stabilization with the functioning of soil microbiota.
... Aerial dispersal of spores influences fungal community structure (Kivlin et al., 2014;Kobziar et al., 2018;Taudière et al., 2017), including ectomycorrhizal colonization of seedlings (Peay et al., 2012). At least some fungal propagules can survive in smoke and bacterial spore abundance declined with distance from fire in a study from ...
Root‐associated fungi play a critical role in plant ecophysiology, growth and subsequent responses to disturbances, so they are thought to be particularly instrumental in shaping vegetation dynamics after fire in the boreal forest. Despite increasing data on the distribution of fungal taxonomic diversity through space and time in boreal ecosystems, there are knowledge gaps with respect to linking these patterns to ecosystem function and process.
Here we explore what is currently known about postfire root‐associated fungi in the boreal forest. We focus on wildfire impacts on mycorrhizal fungi and the relationships between plant–fungal interactions and forest recovery in an effort to explore whether postfire mycorrhizal dynamics underlie plant–soil feedbacks that may influence fire‐facilitated vegetation shifts.
We characterize the mechanisms by which wildfire influences root‐associated fungal community assembly. We identify scenarios of postfire plant–fungal interactions that represent putative positive and negative plant–soil feedbacks that may impact successional trajectories. We highlight the need for empirical field observations and experiments to inform our ability to translate patterns of postfire root‐associated fungal diversity to ecological function and application in models.
We suggest that understanding postfire interactions between root‐associated fungi and plants is critical to predict fire effects on vegetation patterns, ecosystem function, future landscape flammability and feedbacks to climate.
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... High N supply could stimulate aboveground growth without commensurate root development, potentially inhibiting seedling drought resistance and survival (Isaac and Hopkins, 1937, Bensend, 1943, Nilsen, 1995. Alternatively, elevated soil inorganic nitrogen may be associated with other changes, such as reduced mycorrhizal abundance and diversity (Taudière et al., 2017, Remke et al., 2020 or enhanced erosion (Certini, 2005). Additional research is needed to evaluate how fire effects on soil physical properties, biogeochemical processes, and biota affect seedling physiology and demography. ...
Climate warming and an increased frequency and severity of wildfires are expected to transform forest ecosystems, in part through altered post-fire vegetation trajectories. Such a loss of forest resilience to wildfires arises due to a failure to pass though one or more critical demographic stages, or “filters,” including seed availability, germination, establishment, and survival. Here we quantify the relative influence of microclimate and microsite conditions on key stages of post-fire seedling demography in two large, lightning-ignited wildfires from the regionally extensive fire season of 2017 in the northern Rocky Mountains, U.S.A. We tracked conifer seedling density, survival, and growth in the first three years post-fire in 69 plots spanning gradients in fire severity, topography, and climate; all plots were limited to within 100 m of a seed source to assure seed availability. Microclimate conditions were inferred based on measurements in a subset of 46 plots. We found abundant post-fire conifer regeneration, with a median of 2,633 seedlings per hectare after three years, highlighting early resilience to wildfire. This robust regeneration was due in part to moderate post-fire climate conditions, supporting high survivorship (>50% on average) of all seedlings tracked over the study period (n = 763). A statistical model based on variables describing potential seed availability, microclimate, fire severity, understory vegetation, and soil nitrogen availability explained 75% of the variability in seedling density among plots. This analysis highlights the overarching importance of fine-scale heterogeneity in fire effects, which determine microclimate conditions and create diverse microsites for seedlings, ultimately facilitating post-fire tree regeneration. Our study elucidates mechanisms of forest resilience to wildfires and demonstrates the utility of a demographic perspective for anticipating forest responses to future wildfires under changing environmental conditions.
... However, the results from individual studies are controversial, therefore it is difficult to provide a general conclusion about the fire effects on soil bacterial and fungal communities. As a consequence, location-based studies are necessary to better understand this topic [18]. ...
Climate change has strongly increased the fire frequency in Mediterranean forests causing changes in soil bacterial, fungal and microarthropod communities. Fire impacts on soil properties depend on vegetation covers. In this framework, the aim of this research was to evaluate the effects of fire on bacterial, fungal communities and microarthropod community in soils under trees and shrubs in a Mediterranean area. Surface soil cores were sampled in unburnt and burnt (three years since fire occurrence) patches in the Vesuvius National Park trees (Quercus ilex L. and Pinus nigra L.) and shrubs (Ginesta sp., Myrtus communis L., Laurus nobilis L.). Samples were analyzed for abiotic (pH, water content and concentrations of C, N, Corg, P, NO2⁻, NH4⁺ and Pavail) and biotic (bacterial and fungal biomasses, and density, taxa richness, diversity, evenness and QBS-ar of microarthropods) properties. Results showed that, three years since fire, the abiotic properties were recovered in shrub stands but not yet in tree stands. Fire stimulated the development of bacteria only in shrub stands; no effects were observed for the fungal community in both shrub and tree stands; the amount and the taxa richness of microarthropods recovered to the values of the pre-fire conditions in both the stands. In conclusion, in the investigated area, fire differently impacted the vegetation covers, making soils under trees more similar to shrubs with the consequence to reduce the differences between the vegetation covers.
... If we consider fungi by functional group, interestingly, longterm beneficial effects of burning have been observed in boreal forests on saprotrophic Basidiomycota and Ascomycota fungi and on wood-inhabiting fungi (Junninen et al., 2008;Suominen et al., 2018), especially if combined with retention silviculture (Suominen et al., 2015); these effects depend on the type of woody residue burned (stumps, branches or whole trees, Suominen et al., 2019). For ECM fungi, the effect of fire seems to be much more variable (Taudière et al., 2017;Salo and Kouki, 2018), hence more studies involving the whole soil fungal communities are needed (Rincón et al., 2014;Castaño et al., 2020). ...
Mycological resources have attracted considerable interest from the public recently. In this context, forest mycological management of wild mushrooms has emerged a research field and is developing rapidly with the objective to sustainably use and conserve mushrooms in multifunctional forests. Although the term ‘mycosilviculture’ was coined relatively recently, forest management of mycological resources and fungal silviculture began already in the 1980s. This study reviews the literature on the forest management of wild mycological resources with emphasis on studies in Spanish Mediterranean forests. The review covers some of the most important aspects of management, such as the diagnosis of mycological resources through inventory and sampling protocols, predictive models of mushroom yield, stand variables and mycosilvicultural practices that affect mushroom yield and fungal diversity. Finally, the potential of mycorrhizal applications for mycosilviculture is briefly discussed. Most of these studies have been based on carpophore inventories, and few have analyzed soil and air fungal biomass. The Mediterranean climate determines mushroom yields; so far, mushroom yields models have been developed mainly for Boletus gr. edulis and Lactarius gr. deliciosus species and for pine forest ecosystems. In the future, it will be necessary to adjust these models to new climatic conditions, and to investigate the complex interactions between different yield and/or fungal diversity factors, adjust the scale of study and fungus-host specificity. So far, few studies have been carried out on mycosilviculture in Mediterranean forests, addressing the effect of thinning and clearcutting on fungal communities; moreover, experiences of mycological management of shrublands, prescribed burning, management of woody debris or selective planting of mycorrhizal seedlings in forests are scarce. The need to study other Mediterranean forest ecosystems is pointed out.
... The forests of Kashmir Himalaya are prone to intense fires, particularly during autumn. Fire-induced alteration in forest soil properties and diminished ectomycorrhizal communities can persist for decades 47,48 , severely impairing the natural forest regeneration. Additionally, the establishment of newly planted seedlings in these areas depends on the prevailing fraction of ECM fungi retrieved, if any, after fire. ...
Over the past few decades, many countries have attempted to carry out forest landscape restoration over millions of hectares of degraded land. Such efforts, however, have met with limited success because of several factors, including a lack of adequate emphasis on ectomycorrhization of the nursery seedlings. A similar scenario is seen in the Kashmir Himalaya, where the natural regeneration of degraded forests is poor despite ample restoration efforts by forest managers. To overcome this challenge, we identified two promising ectomycorrhizal species, namely Clitocybe nuda and Cortinarius distans , for their use in ectomycorrhization of seedlings of three common conifers, namely Abies pindrow , Cedrus deodara , and Picea smithiana . Laboratory studies were carried out to investigate the requirements for optimum mycelial growth of these ectomycorrhizal fungi. Best ECM mycelial growth was obtained in the basic MMN medium containing glucose as the source of carbon and nitrogen in ammonium form. C. distans showed higher growth than C. nuda across all the treatments and also proved significantly more effective in enhancing the survival and growth of the conifer host plant seedlings. The present study resulted in standardizing the requirements for mass inoculum production of the two mycobionts which could help in successful forest restoration programmes.
... One of the main limiting factors of plant growth in the Mediterranean environment is summer drought, so relative research on the ecophysiological (and especially hydric) effects of ECMs on Mediterranean hosts has been important, but remains still scarce; in fact, most international studies have focused on dry temperate forests (British Columbia and Spain) and Mediterranean forests (Spain and California) (Schoonmaker et al. 2007;Querejeta et al. 2007;Dominguez-Núñez et al. 2006;Morte et al. 2010). Both water availability and fire (Taudière et al. 2017;Vasquez-Gassibe et al. 2014;Martín-Pinto et al. 2006) remain key factors in the interaction of Mediterranean ECM fungi with their hosts and habitats. ...
In the current context in which mycological resources have acquired a strong socio-economic interest, forest mycological management is necessary, with objectives of ecological sustainability in their use and conservation. The key implication of soil fungi in forest biogeochemical processes and the new knowledge on ectomycorrhizal networks and edaphic microbial ecology, make it necessary to rethink traditional silviculture and to study its effects on forest fungal communities. In the Mediterranean region, the current prospects of climate change seem to increase the stress on forest soils and forest life, already affected by poor management and commercial overexploitation of mushrooms, among other causes. We review in this chapter the literature on silvicultural practices that have positively or negatively affected soil fungal diversity and yield, focusing especially on experiences in the Mediterranean forest. We briefly analyze the potential of mycorrhizal applications and the knowledge of ectomycorrhizal networks for their application in forest management. The application of retention silviculture practices, retaining trees, tree patches or understory during forest harvesting can help to preserve ectomycorrhizal networks, buffering the disturbances generated by silvicultural treatments.
... Generally, a disturbance, such as fire, has negative effects on ECM fungi; however, this does not apply to all types of fire Salo and Kouki, 2018). In this study, ECM fungal richness did not differ significantly between treatments, possibly because the heat generated by the prescribed burning was not high enough (Espinosa et al., 2018; to cause change (Dahlberg et al., 2001;Taudière et al., 2017). Hence, mycorrhizal fungi in the soil may have been able to escape the penetrating heat being associated with forests that have been affected by burning for generations (Dahlberg et al., 2001). ...
In the context of global change, wildfires are not only a threat but are also increasing in their severity in forest ecosystems worldwide, affecting and modifying vegetation, wildlife, and fungal dynamics. Mediterranean ecosystems are frequently affected by fire and prescribed burning is being increasingly used as a tool to reduce the risk and severity of wildfires. Although some of the effects of prescribed burning have been studied, the best moment to perform a prescribed burn to reduce the impact of fire on fungal communities has not been fully investigated. In this study, we analysed the effect of prescribed burning in two different seasons (spring and autumn) on soil fungi associated with natural Pinus nigra forests. Four years after prescribed burning was applied, our analyses showed that the total fungal richness and the composition of fungal communities in spring-burned, autumn-burned, and unburned control plots did not differ significantly. However, analyses of specific phyla and functional trophic groups did reveal some significant differences between spring- or autumn-burned plots and unburned control plots. Valuable edible fungi, which were not affected by the prescribed burning, were also found in the study area. Thus, our results suggest that prescribed burning is not only an interesting tool that could be used to reduce the risk of wildfire but also is compatible with the conservation of fungal communities, and could even promote specific valuable edible species, generating complementary incomes for the rural population. Although further studies are needed, our analyses suggest that the season (spring or autumn) in which prescribed burning is performed does not affect fungal conservation and, therefore, does not need to be one of the factors taken into consideration when selecting the most appropriate time to perform a prescribed burning.
... Fire typically reduces the microbial biomass in soil, and the fungal portion is particularly sensitive to burning (Guerrero et al., 2005;O'Dea, 2007;Dooley and Treseder, 2011;Holden and Treseder, 2013;Pressler et al., 2019). Fire has the potential to negatively impact pre-existing ectomycorrhizal communities and subsequent colonization of regenerating seedlings (Cairney and Bastias, 2007;Mataix-Solera et al., 2009;Dove and Hart, 2017;Taudière et al., 2017). Soil saprophytes also can be decimated (Widden and Parkinson, 1975), but these fungi appear less susceptible and may recover faster after fire (Treseder et al., 2004;Sun et al., 2015;Holden et al., 2016). ...
Forest fire is an important occurrence in western landscapes where it helps drive ecosystem processes, and prescribed fire is a common forest management strategy. An initial consequence of fire is burned ground with reduced biodiversity. Numerous studies have documented how forests recover after fire in terms of plant regeneration and animal colonization, but little is known of the ecological roles fungi play in this process. Pyrophilous (burn-loving) fungi are documented to reliably produce large fruitings and copious mycelium on burns after fire in North America, Europe, Asia, and Australia. We hypothesize that pyrophilous fungi help bind and stabilize soil after forest fires via their extensive mycelial network. Three pyrophilous fungi, Geopyxis carbonaria, Pyronema omphalodes, and Morchella septimelata were tested for their ability to aggregate burned soil. The fungi were isolated from burn sites, grown in vitro, and inoculated onto sterilized soil from a natural burn. The ability of each species to aggregate soil in comparison to non-inoculated controls was assessed after 10, 20, 30, and 40 days, using a wet sieve aggregate stability test. All three fungi increased soil aggregation after 10 days, and this increase was maintained for the 40-day period. The burned soil was up to 30% more aggregated when a fungus was present; results provide the first direct evidence that pyrophilous fungi aggregate burn soil. This further implies that these fungi play a role in reducing soil erosion and enhancing soil moisture soon after fire in burned forests. Pyrophilous fungi also decompose charred material, sequester carbon, and capture transient nitrogen pulses after fire. This overlooked group of fungi may be critical in enhancing conditions for plant regeneration after forest fire at an early stage in recovery. Consideration should be given to avoiding or delaying restoration activities that disturb this natural process, especially those that contribute to soil compaction, during early post-fire recovery when these fungi are proliferating.
... Previous reviews have described a decrease in microbial biomass after a fire event [7,12], with a higher impact on the fungal biomass [13], and its recovery may require months or even years. Long-term shifts in the composition of ectomycorrhizal fungal communities have been described after wildfires and prescribed fires [14]. The fire impact on soil and the following postfire recovery of the microbiota can differ depending on the fire recurrence. ...
The ecosystem response to fire is often linked to fire severity and recurrence, with potentially larges consequences on both above- and below-ground processes. Understanding the fire impact has become increasing important in the light of recent changes to disturbance regimes due to climate change. While the impacts on the above vegetation and the below soil physical and chemical properties are well documented, it remains unclear how fire affects the fine-scale microorganisms. Microbial communities are responsible for driving essential ecosystem processes and particularly sensitive to changes induced in soil quality by wildfire or prescribed fire disturbances. This work is a review of the last three years literature, dealing with the fire impact on mass, activity and diversity of soil microorganisms from soil A horizon.
... Moreover, saprobic fungi co-inhabit the rhizosphere with EcM fungi; playing key roles in decomposition (Smith & Read, 2009), soil moisture retention (Egger and Paden, 1986), and are vital for the formation, stabilization, and disintegration of soil aggregates (Lehmann and Rillig, 2015;Ritz and Young, 2004;Tisdall et al., 2012). Wildfire can directly alter the soil microbial community through selective heat-induced mortality (DeBano et al., 1998), resulting in negative to neutral effects (Taudière et al., 2017). In addition, wildfire leads to indirect long-term effects via host mortality (Buscardo et al., 2011;Pec et al., 2017;Sun et al., 2015), shifts in plant dominance (Ning et al., 2021), and litter input and structure (Bhatnagar et al., 2018;Ficken and Wright, 2017). ...
Ponderosa pine (Pinus ponderosa) forests are increasingly experiencing high-severity, stand-replacing fires. Whereas alterations to aboveground ecosystems have been extensively studied, little is known about soil fungal responses in fire-adapted ecosystems. We implement a chronosequence of four different fires that varied in time since fire, 2 years (2015) to 11 years (2006) and contained stands of high severity burned P. ponderosa in eastern Washington and compared their soil fungal communities to adjacent unburned plots. Using Illumina Miseq (ITS1), we examined changes in soil nutrients, drivers of species richness for ectomycorrhizal (plant symbionts) and saprobic (decomposers) fungi, community shifts, and post-fire fungal succession in burned and unburned plots. Ectomycorrhizal richness was 43.4% and saprobic richness 12.2% lower in the burned plots, leading to long-term alterations to the fungal communities that did not return to unburned levels, even after 11 years. Differences in the post-fire fungal community were driven by pyrophilous, “fire-loving” fungi, including the ectomycorrhizal Ascomycete genera Pustularia and Wilcoxina, and the saprobic Basidiomycete genus Geminibasidium. Ectomycorrhizal and saprobic fungi were intimately linked to the soil environment: depth of the organic matter, total carbon, total nitrogen, and their interaction with fire predicted ectomycorrhizal richness. Whereas total carbon, time since fire, treatment, and the interaction between time since fire and treatment predicted saprobic richness. We conclude that high-severity wildfires lead to lower ectomycorrhizal richness and significantly altered ectomycorrhizal and saprobic communities in fire-adapted ecosystems, selecting resilient and fire-adapted species, such as W. rehmii and Geminibasidium sp., thus initiating post-fire succession.
... The most recent papers are listed first. Shaded cells indicate whether each paper contained discussion (Discuss) or data-based inferences (Data) concerning fire attributes (References not cited in the article main text but included in the literature review and in Additional file 1 are: Abella and Springer 2015;Adams et al. 2013;Bentley and Penman 2017;Beringer et al. 2015;Brose 2014;Brown et al. 2016;Campbell 2012;Cannon et al. 2017;Cawson et al. 2012;Contreras et al. 2011;Darracq et al. 2016;Dey and Schweitzer 2018;Driscoll et al. 2010a;Driscoll et al. 2010b;Engstrom 2010;Fernandes 2013;Freeman et al. 2017;Frelich et al. 2017;Fulé et al. 2012;Geiser et al. 2018;Hessburg et al. 2015;Hesseln 2018;Hunt et al. 2014;Hutchen et al. 2017;McIver et al. 2013;Meador et al. 2017;Miesel et al. 2012;Page et al. 2014;Parkins et al. 2017;Prichard et al. 2017;Ratajczak et al. 2014;Robinson et al. 2013;Slapcinsky et al. 2010;Taudiére et al. 2017). ...
The idea that not all fire regimes are created equal is a central theme in fire research and conservation. Fire frequency ( i.e., temporal scale) is likely the most studied fire regime attribute as it relates to conservation of fire-adapted ecosystems. Generally, research converges on fire frequency as the primary filter in plant community assembly and structure, which is often critical to conservation goals. Thus, conservation success is commonly linked to fire frequency in fire regimes.
The spatial scale of fire may also be vital to conservation outcomes, but this attribute is underrepresented in the primary literature. In our global, contemporary literature search, we found 37 published syntheses concerning the effects of prescribed fire in conservation over the last decade. In those syntheses, only 16% included studies that reported data-based inferences related to the spatial scale of the fire, whereas 73% included discussion of empirical studies on the temporal scale. Only one of the syntheses discussed studies that explicitly tested the effects of spatial extent, and none of those studies were experiments manipulating spatial scale. Further, understanding spatial-scale-dependent patterns may be relevant because two databases of fire-occurrence data from the United States indicated that spatial scale among lightning-ignited and prescribed fires may have been mismatched over the past few decades.
Based on a rich ecological literature base that demonstrates pervasive scale-dependent effects in ecology, spatial-scale-dependent relationships among prescribed fire regimes and conservation outcomes are likely. Using examples from the southeastern United States, we explored the potential for scale-dependent ecological effects of fire. In particular, we highlighted the potential for spatial scale to (a) influence wildlife populations by manipulating the dispersion of habitat components, and (b) modulate plant community assembly and structure by affecting seed dispersal mechanics and spatial patterns in herbivory. Because spatial-scale-dependent outcomes are understudied but likely occurring, we encourage researchers to address the ecological effects of spatial scale in prescribed-fire regimes using comparative and manipulative approaches.
... Relative to proximate areas without a recent history of fire, burned areas in the Madrean Sky Island ranges have EM fungal communities that remain distinct ca. 12e16 years after wildfire, as observed in other regions (e.g, see Glassman et al., 2016;Taudi ere et al., 2017). As fire intervals grow shorter and fires become more widespread and intense, the potential for local recolonization from unburned patches likely will decrease in these isolated forests, such that the potential for species loss from isolated Sky Island ranges appears to be high. ...
With a warming and drying climate, coniferous forests worldwide are increasingly threatened by wildfires. We examined how fire impacts ectomycorrhizal (EM) fungi associated with Pinus ponderosa, an important tree species in western North America. In the biodiverse Madrean Sky Islands, P. ponderosa forests exist on insular mountains separated by arid lands. How do EM fungi in these isolated ranges respond to fire, and can data from individual ranges predict community shifts after fire at a regional scale? By comparing areas in two ranges that experienced moderate fires 12–16 y earlier, and proximate areas in each range without recent fire, we reveal pervasive effects on diversity and composition of EM communities more than a decade after moderate fires occurred. Post-fire differences in EM communities in different ranges highlight the challenge of predicting fungal community shifts in these isolated forests, despite similarities of climate, plant communities, and fire severity.
... Both arbuscular (AM) and ectomycorrhizal (EM) fungi provide plant hosts with nutrients (mainly P and N respectively) in return for carbon. Both groups also display seasonal peaks in abundance (Harvey, Jurgensen and Larsen 1978;Santos-Gonzalez, Finlay and Tehler 2007), and are strongly impacted by fire (Klopatek, Debano and Klopatek 1988;Dhillion and Anderson 1993;Taudière, Richard and Carcaillet 2017). Fire is well known to decrease the richness and in situ colonization of AM and EM fungal communities (Dove and Hart 2017). ...
Fire alters microbial community composition, and is expected to increase in frequency due to climate change. Testing whether microbes in different ecosystems will respond similarly to increased fire disturbance is difficult though, because fires are often unpredictable and hard to manage. Fire recurrent or pyrophilic ecosystems, however, may be useful models for testing the effects of frequent disturbance on microbes. We hypothesized that across pyrophilic ecosystems, fire would drive similar alterations to fungal communities including altering seasonal community dynamics. We tested fire's effects on fungal communities in two pyrophilic ecosystems, a Longleaf pine savanna and tallgrass prairie. Fire caused similar fungal community shifts including a) driving immediate changes that favored taxa able to survive fire and take advantage of post-fire environments, and b) altering seasonal trajectories due to fire-associated changes to soil nutrient availability. This suggests that fire has predictable effects on fungal community structure and intra-annual community dynamics in pyrophilic ecosystems, and that these changes could significantly alter fungal function. Parallel fire responses in these key microbes may also suggest that recurrent fires drive convergent changes across ecosystems, including less fire frequented systems that may start burning more often.
... Is there any key microbial group helping the process of recovery after fire? Although researchers have conducted some preliminary studies on soil microbial communities after fire (Mataix-Solera et al. 2009;Taudière et al. 2017;Catalanotti et al. 2018), these questions have not yet to be well answered. In this study, NTF collected from two different soil depths (0-10 and 10-20 cm) in two different burned sites and corresponding unburned sites (CS sites and YL sites) were analyzed. ...
Soil microbes’ response to sudden environmental changes is very complicated and has been lively debated. There are a handful of questions yet to answer: are there any succession rules for different soil microbial species to fit in the suddenly changed environment? And what is the correlation between the community succession and the habitat recovery? These questions remain unanswered yet. Nematode-trapping fungi (NTF) play a very important role in the soil ecosystem and can be studied by traditional culture method easily. So, in this study, the NTF community in two burned sites at two depths (0–10 and 10–20 cm) was investigated in comparison with adjacent unburned sites. While the original NTF community structure was rather different in the two unburned sites, the NTF community presented a consistent pattern in the two burned sites: (1) considerable amount of NTF in the shallow soil (0–10 cm) was killed by the extremely high temperature of fire and the vacant niches were subsequently replaced with NTF communities that were originally distributed in the deep soil (10–20 cm); (2) dominant species in the community changed from Arthrobotrys fungi which showed stronger saprophytic ability to Dactylellina fungi which showed stronger capturing ability; and (3) the vacant niche caused by the movement of Dactylellina fungi was taken by Drechslerella fungi. The study shows that microbes inhabited in the deep soil played a critical role in the after-fire process to recovery of the soil ecological system.
... Studies reporting pyrophilous fungi have largely focused on boreal forests (Dahlberg et al. 2001;de Groot et al. 2013;Sun et al. 2015), western North American coniferous forests (Bruns et al. 2002(Bruns et al. , 2005Westerling et al. 2006;Sun et al. 2015;Reazin et al. 2016), the Mediterranean (Buscardo et al. 2010), and Australia (McMullan-Fisher et al. 2002. Taudière et al. (2017) summarized studies involving both wildfires and prescribed burns and their effects on ectomycorrhizal (ECM) fungi worldwide, but missing from all these studies are data for pyrophilous fungi in eastern North America. The reason for this lack of coverage may be that fire prevention strategies in eastern North American temperate forests have successfully suppressed forest fires for approximately 100 y (Nowacki and Abrams 2008;Aldrich et al. 2010;Flatley et al. 2011Flatley et al. , 2013Lafon et al. 2017). ...
Following a late fall wildfire in 2016 in the Great Smoky Mountains National Park, pyrophilous fungi in burn zones were documented over a 2-y period with respect to burn severity and phenology. Nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) barcodes were obtained to confirm morphological evaluations. Forty-one taxa of Ascomycota and Basidiomycota were identified from burn sites and categorized as fruiting only in response to fire or fruiting enhanced by fire. Twenty-two species of Pezizales (Ascomycota) were among the earliest to form ascomata in severe burn zones, only one of which had previously been documented in the Great Smoky Mountains National Park. Nineteen species of Basidiomycota, primarily Agaricales, were also documented. Among these, only five species (Coprinellus angulatus, Gymnopilus decipiens, Lyophyllum anthracophilum, Pholiota carbonicola, and Psathyrella pennata) were considered to be obligate pyrophilous taxa, but fruiting of two additional taxa (Hygrocybe conica and Mycena galericulata) was clearly enhanced by fire. Laccaria trichodermophora was an early colonizer of severe burn sites and persisted through the winter of 2017 and into spring and summer of 2018, often appearing in close association with Pinus pungens seedlings. Fruiting of pyrophilous fungi peaked 4–6 mo post fire then diminished, but some continued to fruit up to 2.5 y after the fire. In all, a total of 27 previously unrecorded taxa were added to the All Taxa Biodiversity Inventory (ATBI) database (~0.9%). Most pyrophilous fungi identified in this study are either cosmopolitan or have a Northern Hemisphere distribution, but cryptic endemic lineages were detected in Anthracobia and Sphaerosporella. One new combination, Hygrocybe spadicea var. spadicea f. odora, is proposed.
... bryophytes, fungi, lichens, arthropods, or small vertebrates) could provide informative complementary perspectives on Mediterranean ecosystems (e.g. Jacquet and Prodon 2009;Taudière et al. 2017b;Perez-Valera et al. 2018;Hinojosa et al. 2019;Lazarina et al. 2019). ...
Changes in community diversity and dynamics after fires in Mediterranean ecosystems are rarely investigated more than a few years after the fire even though pronounced changes can be expected in the longer term due to substitution of canopy species. Pinus halepensis is strongly promoted by wildfire and should therefore be gradually substituted by Quercus species as the time since the last fire increases. We hypothesized that this tree substitution would cause changes in understorey plant diversity by changing resource availability and the abundance and properties of woody debris, leading to changes in biogeochemical processes. To test this hypothesis, we investigated the effect of the time since last fire on vascular plant composition and diversity by studying a 130 years post-fire chronosequence in mixed Mediterranean forests. The canopy composition went from domination by Pinus halepensis to domination by Quercus 70 years after the most recent fire. This transformation was associated with a change in the understorey involving a rarefaction of species present during the first decades after the fire. The plant density or cover also changed with time since the last fire, indicating a succession driven by species rarefaction rather than substitution. The mean richness and Shannon diversity per quadrat were highest shortly after the fire, and were significantly lower 70 or more years after the last fire. Fires are important for supporting highly diversified fire-dependent plant communities, and total plant richness decreases monotonically over time after fires, suggesting that fire suppression may reduce diversity in Mediterranean forests.
... In contrast to rapid colonization by the post-fire fungi, recovery of soil fungal communities to pre-fire condition may take more than ten years (Dooley and Treseder, 2012;Oliver et al., 2015;Hart et al., 2018). Taudière et al. (2017) have reviewed the main studies on the effect of fire on ectomycorrhizal species and have concluded that prescribed burning has a negative effect on the aboveground ectomycorrhizal fungal richness (i.e. reproductive structures). ...
The influence of forest management on fungal diversity and community composition has been the subject of a wide number of studies over the last two decades. However, the difficulty of studying the complex kingdom of fungi under real forest conditions has led to rather scattered scientific knowledge. Here, we provide the current state of knowledge suggesting future research directions regarding (i) stand structure attributes (age, tree cover, stand density, tree species composition), (ii) management history (managed vs unmanaged), (iii) silvicultural treatments (thinning, clearcutting, shelterwood methods, selective cutting) and (iv) other anthropogenic disturbances (mushroom picking, salvage logging, prescribed burning, fertilization) affecting fungal diversity and community composition. The reviewed studies reported a positive correlation between fungal diversity and stand structure variables such as canopy cover, basal area of the stand and tree species diversity, particularly for mycorrhizal species. Abundance and diversity in size, tree species and decomposition stage of deadwood are reported as positively related to richness of wood-inhabiting fungi. The main findings about the effects of silvicultural practices suggest that the higher is the management intensity the lower is the diversity of ectomycorrhizal and wood-inhabiting species, at least in the short term. We have therefore reported those silvicultural practices which may reduce trade-offs between timber harvesting and fungal diversity conservation. Indeed, fungal diversity can be conserved in managed forests if (i) low impact logging operations are performed; (ii) stand structural complexity and late-successional forest characteristics are enhanced; (iii) deadwood amount and diversity is promoted, (iv) landscape heterogeneity and connectivity is improved or maintained.
Fungi play key roles in the fire‐fuel feedbacks that structure ~40% of the Earth's terrestrial ecosystems, yet a general understanding of fungal responses to fire is lacking. While fire and associated stressor effects on fungi vary based on fire regime components like severity, intensity, and frequency, their influence on fungi can be categorized into three primary phases based on when they influence fungi: during fire, early post‐fire, and later post‐fire. We first identify key fire‐associated phenomic traits and similarities in fungal responses to fire across time. Then, we synthesize this information by linking fire effects to specific fungal traits and response groups to produce trait profiles useful for classifying pyrophilic fungi. The goal of this review is to consolidate fire‐associated phenomic trait data into trait profiles that can be used in combination with fungal genomic data and associated methodologies. These profiles produce an invaluable framework for understanding fungal roles in fire regimes and identify previously unknown trends in fungal responses to fire and associated stressors including heat shock responses, pigmentation, and dispersal into and out of burned environments.
Wildfire is a widespread phenomenon on the earth that has affected most ecosystems and is responsible for enormous economic and environmental damage. The Greater Khingan Mountains, the south boundary of the boreal forest, are a fire-prone area. However, the effect of fire disturbance on tree growth in response to climate warming is unknown. To predict the future dynamics of boreal forests after fire disturbance and their feedback on climate change, we analyzed Larix gmelinii growth-climate relationships in burned areas at six sites. The result showed a significant decline in the growth of burned trees in all locations except CY1 during the fire years. There was a growth release 3–5 years after the fire disturbance. The result of growth-climate relationships found that the response of CY1 and GH burned and unburned trees to mean temperature changed from a positive to a negative correlation before and after the fire year. Changes in tree growth response to PDSI were significant for both burned and unburned trees, suggesting that this change in response is related to fire disturbance and influenced by climate warming and drying in recent decades. The resistance of larch to fire showed that in the three years before and after the fire year, there was a significant reduction in the growth of burned larch, except for CY1. Our findings suggested that burned and unburned larch respond differently to climate change. Wildfires change the relationship between the radial growth of trees and climate factors. It may also alter the structural composition and biodiversity of boreal forests.
Background
Global warming and drying have markedly enhanced in most forests the risk of fires across the world, which can affect the taxonomic and functional composition of key tree-associated organisms such as ectomycorrhizal (ECM) fungi. The present study was conducted to characterise the alterations in the extent of root ECM colonisation, the ECM fungal communities, and their exploration types ( i.e. , indicator of ECM soil foraging strategies) in regenerated pines within a burned site as compared with an unburned site (five years after the fire event) in the Forest District Myszyniec, Poland.
Methods
To assess the ECM fungal communities of burned and control sites, soil soil-root monoliths were collected from the study sites in September 2019. A total of 96 soil subsamples were collected for soil analysis and mycorrhizal assessment (6 trees × 2 sites × 4 study plots × 2 microsites (north and south) = 96 subsamples).
Results
The percentage of root ECM colonisation was significantly lower in the burned site in comparison with the unburned (control) site. However, the ECM species richness did not differ between the control and burned sites. The identified ECM species in both sites were Imleria badia, Thelephora terrestris, Russula paludosa , R. badia , R. turci , R. vesca , Lactarius plumbeus, Phialocephala fortinii , and Hyaloscypha variabilis . The most frequent species in the burned and control sites were I. badia and T . terrestris, respectively. The relative abundances of contact, medium-distance smooth and long-distance exploration types in the burned site were significantly different from the control site, dominated by the medium-distance exploration type in both sites. The abundance of the long-distance exploration type in the burned site was markedly greater (27%) than that of the control site (14%), suggesting that the fire event had favoured this ECM foraging strategy. The results demonstrated that the fire led to reduced ECM colonisation of Scots pine trees in the burned site whereas the species richness was not affected, which can be attributed to degrees of fire-resistance in the ECM species, survival of ECM propagules in deeper soil layers, and/or continuous entry of spores/propagules of the ECM fungi from the adjacent forests via wind, water run-off or animals.
We tested for fire-induced (5-6 years post-fire) changes in the structure and functioning of the soil food web along a 3000-km north-south transect across European Russia, spanning all major forest types in the northern hemisphere outside the tropics. The total biomass of the detrital food web, including microbes and invertebrates, was not affected by fire. However, fire reduced the bio-mass of microfauna and mites, but had no impact on mesofauna or macrofauna. Fire also reduced rates of carbon (C) mobilisation by soil biota. Our results demonstrate that fire-induced shifts in soil food webs have significant short-term effects on forest soil C cycling, but that these effects vary across forest types and geographic locations.
Wildfires can negatively affect ectomycorrhizal (EM) fungal communities. However, potential shifts in community structures due to wildfires have rarely been evaluated in the forests of eastern Eurasia, where surface fires are frequent. We investigated EM fungal communities in a Larix gmelinii-dominated forest that burned in 2003 in Zeya, in the Russian Far East. A total of 120 soil samples were collected from burned and adjacent unburned forest sites. The EM fungal root tips were morphotyped and internal transcribed spacer (ITS) sequences were obtained for fungal identification. We detected 147 EM fungal operational taxonomic units, and EM fungal richness was 25% lower at the burned site than at the unburned site. EM fungal composition was characterized by the occurrence of disturbance-adapted fungi (Amphinema and Wilcoxina) at the burned site and late-successional fungi (Lactarius, Russula and Cortinarius) at the unburned site. These findings suggest that the EM fungal communities did not recover to pre-fire levels 16 years after the fire. Suillus species were the dominant EM fungi on L. gmelinii, with greater richness and frequency at the burned site. Both Larix and Suillus exhibit adaptive traits to quickly colonize fire-disturbed habitats. Frequent surface fires common to eastern Eurasia are likely to play important roles in maintaining Larix forests, concomitantly with their closely associated EM fungi.
Wildfires trigger changes in vegetation dynamics if the existing community does not resist the fire and succumbs. However, the same vegetation state may still occur if populations show post-fire resilience, that is, if they are able to regenerate after fire. Such regeneration will be a function of interactions between propagule availability (aerial or soil seed banks or other seed sources nearby), its establishment success (dependent on soil resources, dormancy break, herbivores, and microsite conditions), fire recurrence, and mycorrhizal networks. When pre-fire species fail to survive and regenerate after the fire, changes in the vegetation state may lead to either a forested or a deforested state, depending on legacies from the previously established community, climatic conditions and water balance, and other processes. Climate change may compromise post-fire state changes when newly established communities cannot survive under the novel environmental conditions expected for the end of this century. Here we review overall post-fire vegetation changes, with a particular emphasis on Mediterranean environments.
As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%–85% of permafrost carbon release can still be avoided if human emissions are actively reduced.
Florestas em solos arenosos são consideradas como hospedeiras de muitos fungos ectomicorrízicos (EM), como demonstrado pelas numerosas coletas feitas por Rolf Singer na região do Rio Negro, Amazonas, no final dos anos 70. Apesar do reconhecimento da importância dos fungos ectomicorrízicos em florestas em solos arenosos, não houve nenhum estudo sistemático da diversidade e da composição taxonômica nas florestas em solos arenosos ou mesmo mais amplamente nas terras baixas da Floresta Amazônica. Para ter uma visão global da diversidade e da distribuição de fungos EM em florestas em solos arenosos, foram coletados basidiomas desses fungos em 10 parcelas de florestas em solos arenosos no Brasil e na Guiana Francesa entre 2012 e 2014. Além disso, uma busca foi feita por espécimes depositados em herbários brasileiros que tinham a informação de serem coletas feitas em solo arenoso. Nas 10 parcelas amostradas foram coletados 221 espécimes e 62 morfoespécies, o que confirma que todas as florestas em solos arenosos hospedam fungos EM. Recuperamos 1006 espécimes registrados em 18 herbários brasileiros, dos quais 137 espécimes e 52 espécies são registros de florestas em solos arenosos principalmente no estado do Amazonas, Brasil. Russulaceae e Amanitaceae foram frequentes em todos os habitats e Cortinarius foi o táxon mais frequente em solo arenoso. Os resultados apresentados enfatizam a alta diversidade e heterogeneidade das comunidades de EM em florestas em solos arenosos, assim como a ampla distribuição de fungos em todo o Brasil, não exclusivamente em florestas em solos arenosos.
After severe wildfires, pine recovery depends on ectomycorrhizal (ECM) fungal spores surviving and serving as partners for regenerating forest trees. We took advantage of a large, severe natural forest fire that burned our long-term study plots to test the response of ECM fungi to fire. We sampled the ECM spore bank using pine seedling bioassays and high-throughput sequencing before and after the California Rim Fire. We found that ECM spore bank fungi survived the fire and dominated the colonization of in situ and bioassay seedlings, but there were specific fire adapted fungi such as Rhizopogon olivaceotinctus that increased in abundance after the fire. The frequency of ECM fungal species colonizing pre-fire bioassay seedlings, post-fire bioassay seedlings and in situ seedlings were strongly positively correlated. However, fire reduced the ECM spore bank richness by eliminating some of the rare species, and the density of the spore bank was reduced as evidenced by a larger number of soil samples that yielded uncolonized seedlings. Our results show that although there is a reduction in ECM inoculum, the ECM spore bank community largely remains intact, even after a high-intensity fire. We used advanced techniques for data quality control with Illumina and found consistent results among varying methods. Furthermore, simple greenhouse bioassays can be used to determine which fungi will colonize after fires. Similar to plant seed banks, a specific suite of ruderal, spore bank fungi take advantage of open niche space after fires.The ISME Journal advance online publication, 16 October 2015; doi:10.1038/ismej.2015.182.
The ectomycorrhizal (ECM) symbiosis connects mutualistic plants and fungal species into bipartite networks. While links between one focal ECM plant and its fungal symbionts have been widely documented, systemic views of ECM networks are lacking, in particular, concerning the ability of fungal species to mediate indirect ecological interactions between ECM plant species (projected-ECM networks). We assembled a large dataset of plant–fungi associations at the species level and at the scale of Corsica using molecular data and unambiguously host-assigned records to: (i) examine the correlation between the number of fungal symbionts of a plant species and the average specialization of these fungal species, (ii) explore the structure of the plant–plant projected network and (iii) compare plant association patterns in regard to their position along the ecological succession. Our analysis reveals no trade-off between specialization of plants and specialization of their partners and a saturation of the plant projected network. Moreover, there is a significantly lower-than-expected sharing of partners between early- and late-successional plant species, with fewer fungal partners for early-successional ones and similar average specialization of symbionts of early- and late-successional plants. Our work paves the way for ecological readings of Mediterranean landscapes that include the astonishing diversity of below-ground interactions.
We studied belowground and aboveground diversity and distribution of ectomycorrhizal (EM) fungal species colonizing Coccoloba uvifera (L.) L. (seagrape) mature trees and seedlings naturally regenerating in four littoral forests of the Guadeloupe island (Lesser Antilles). We collected 546 sporocarps, 49 sclerotia, and morphotyped 26,722 root tips from mature trees and seedlings. Seven EM fungal species only were recovered among sporocarps (Cantharellus cinnabarinus, Amanita arenicola, Russula cremeolilacina, Inocybe littoralis, Inocybe xerophytica, Melanogaster sp., and Scleroderma bermudense) and one EM fungal species from sclerotia (Cenococcum geophilum). After internal transcribed spacer (ITS) sequencing, the EM root tips fell into 15 EM fungal taxa including 14 basidiomycetes and 1 ascomycete identified. Sporocarp survey only weakly reflected belowground assessment of the EM fungal community, although 5 fruiting species were found on roots. Seagrape seedlings and mature trees had very similar communities of EM fungi, dominated by S. bermudense, R. cremeolilacina, and two Thelephoraceae: shared species represented 93 % of the taxonomic EM fungal diversity and 74 % of the sampled EM root tips. Furthermore, some significant differences were observed between the frequencies of EM fungal taxa on mature trees and seedlings. The EM fungal community composition also varied between the four investigated sites. We discuss the reasons for such a species-poor community and the possible role of common mycorrhizal networks linking seagrape seedlings and mature trees in regeneration of coastal forests.
The impacts of climate change on fires are expected to be highly variable spatially and temporally. In heavily anthropized landscapes, the great number of factors affecting fire regimes further limits our ability to predict future fire activity caused by climate. To address this, we develop a new framework for analysing regional changes in fire regimes from specific spatiotemporal patterns of fires and climate, so-called pyroclimates. We aim to test the trends of fire activity and climate (1973–2009) across the Mediterranean and mountain ecosystems of south-eastern France, and to define the spatial distribution of pyroclimates. Stepwise-PCA and cluster analyses reveal that three pyroclimates capture the spatiotemporal patterns associated with fire regime and climatic conditions. Trend tests indicate a high significant increase in spring temperature and fire weather severity for most of the study area. In contrast, a general decreasing pattern of fire activity is observed since the early 1990s, specifically during summer in historically burned regions. However, winter and spring fires are becoming more frequent and extensive in less fire-prone mountains. Cross-correlation analyses indicate that inter-annual variations in extreme fire weather and fire activity were highly correlated. However, the intensity of relationships is pyroclimate-dependent. Our findings reveal that fire-climate relationships changed rapidly over space and time, presumably according to regional changes in land-use and fire policy. Assessing pyroclimates offers new perspectives for fire management and policy by delineating homogeneous zones with respect to fire, climate and their recent trends, and by revealing geographic contrasts in the underlying fire drivers.
Applying early names, with or without original material, to genealogical species is challenging. For morels this task is especially difficult because of high morphological stasis and high plasticity of apothecium color and shape. Here we propose a nomenclatural revision of true morels (Morchella, Pezizales) from Europe and North America, based on molecular phylogenetic analyses of portions of the genes for RNA polymerase II largest subunit (RPB1) and second largest subunit (RPB2), translation elongation factor-1α (TEF1), the nuc rDNA region encompassing the internal transcribed spacers 1 and 2, along with the 5.8S rDNA (ITS), and partial nuc 28S rDNA D1-D2 domains (28S). The 107 newly sequenced collections were from both continents, including 48 types, together with previously published sequences. Names are applied to 30 of the 65 currently recognized genealogical species. Results of the present study revealed that the number of Morchella species in Europe (n = 21) is nearly identical to that in North America (n = 22). Only seven species were found on both continents, consistent with previous reports of high continental endemism within the genus. Presently it is not possible to tell whether the transoceanic disjunctions were due to human activities, migration across a Bering land bridge or long-distance dispersal. In an effort to stabilize the taxonomy, due in part to the recent publication of synonyms for 11 of the species, accepted names are presented together with their corresponding later synonyms. A new subclade that includes holotypes of M. castanea and M. brunneorosea is identified in sect. Morchella (Esculenta Clade). Lectotypes for Morchella deliciosa, M. eximia and M. tridentina are designated here, as well as epitypes for M. dunalii, M. eximia, M. purpurascens and M. vulgaris. Morchella conica was determined to be illegitimate, and further research is required to determine the identity of M. elata and M. inamoena.
Copyright © 2014, Mycologia.
Following a pine beetle epidemic in British Columbia, Canada, we investigated the effect of fire severity on rhizosphere soil chemistry and ectomycorrhizal fungi (ECM) and associated denitrifying and nitrogen (N)-fixing bacteria in the root systems of regenerating lodgepole pine seedlings at two site types (wet and dry) and three fire severities (low, moderate, and high). The site type was found to have a much larger impact on all measurements than fire severity. Wet and dry sites differed significantly for almost all soil properties measured, with higher values identified from wet types, except for pH and percent sand that were greater on dry sites. Fire severity caused few changes in soil chemical status. Generally, bacterial communities differed little, whereas ECM morphotype analysis revealed ectomycorrhizal diversity was lower on dry sites, with a corresponding division in community structure between wet and dry sites. Molecular profiling of the fungal ITS region confirmed these results, with a clear difference in community structure seen between wet and dry sites. The ability of ECM fungi to colonize seedlings growing in both wet and dry soils may positively contribute to subsequent regeneration. We conclude that despite consecutive landscape disturbances (mountain pine beetle infestation followed by wildfire), the "signature" of moisture on chemistry and ECM community structure remained pronounced.
Boreal forest soils store a major proportion of the global terrestrial carbon (C) and below‐ground inputs contribute as much as above‐ground plant litter to the total C stored in the soil. A better understanding of the dynamics and drivers of root‐associated fungal communities is essential to predict long‐term soil C storage and climate feedbacks in northern ecosystems.
We used 454‐pyrosequencing to identify fungal communities across fine‐scaled soil profiles in a 5000 yr fire‐driven boreal forest chronosequence, with the aim of pinpointing shifts in fungal community composition that may underlie variation in below‐ground C sequestration.
In early successional‐stage forests, higher abundance of cord‐forming ectomycorrhizal fungi (such as Cortinarius and Suillus species) was linked to rapid turnover of mycelial biomass and necromass, efficient nitrogen (N) mobilization and low C sequestration. In late successional‐stage forests, cord formers declined, while ericoid mycorrhizal ascomycetes continued to dominate, potentially facilitating long‐term humus build‐up through production of melanized hyphae that resist decomposition.
Our results suggest that cord‐forming ectomycorrhizal fungi and ericoid mycorrhizal fungi play opposing roles in below‐ground C storage. We postulate that, by affecting turnover and decomposition of fungal tissues, mycorrhizal fungal identity and growth form are critical determinants of C and N sequestration in boreal forests.
Altered disturbance regimes and novel introductions are causing rapid shifts in the distribution of pines (Pinus L.). The functionally obligate symbiosis between pines and ectomycorrhizal (EM) fungi dictates that shifts in the distribution of one partner will affect the distribution of the other. In this review, we examine evidence for three hypotheses. (1) The loss of photosynthates through stress or tree mortality decreases the abundance of EM fungi and selects for less carbon-demanding species. (2) Pine introductions initiate establishment of novel EM fungal communities. (3) The extent of shifts in EM fungal abundance and community composition is mediated by surrounding vegetation. We find support for these hypotheses though changes in EM fungal abundance are variable and context-dependent. We posit that the consequences of shifts in EM fungal abundance and community composition extend beyond the individual tree to the landscape; these changes may affect population dynamics of both symbionts, ecosystem processes, and the conservation and evolution of fungi. In addition to conducting baseline surveys to assess the distribution of EM fungi, increasing our understanding of their function, morphology, propagation, and controls on host-specificity, and shifts would also assist in predicting the trajectory of ecosystems following the loss or gain of pine.
The impacts of escalating wildfire in many regions — the lives and homes lost, the expense of suppression and the damage to ecosystem services — necessitate a more sustainable coexistence with wildfire. Climate change and continued development on fire-prone landscapes will only compound current problems. Emerging strategies for managing ecosystems and mitigating risks to human communities provide some hope, although greater recognition of their inherent variation and links is crucial. Without a more integrated framework, fire will never operate as a natural ecosystem process, and the impact on society will continue to grow. A more coordinated approach to risk management and land-use planning in these coupled systems is needed.
Most fungi produce some type of durable microscopic structure such as a spore that is important for dispersal and/or survival under adverse conditions, but many species also produce dense aggregations of tissue called sclerotia. These structures help fungi to survive challenging conditions such as freezing, desiccation, microbial attack, or the absence of a host. During studies of hypogeous fungi we encountered morphologically distinct sclerotia in nature that were not linked with a known fungus. These observations suggested that many unrelated fungi with diverse trophic modes may form sclerotia, but that these structures have been overlooked. To identify the phylogenetic affiliations and trophic modes of sclerotium-forming fungi, we conducted a literature review and sequenced DNA from fresh sclerotium collections. We found that sclerotium-forming fungi are ecologically diverse and phylogenetically dispersed among 85 genera in 20 orders of Dikarya, suggesting that the ability to form sclerotia probably evolved ≥14 different times in fungi.
It has been suggested that on a global scale, fire activity changes along the productivity/aridity gradient following a humped relationship, i.e. the intermediate fire–productivity hypothesis. This relation should be driven by differing relative roles of the main fire drivers (weather and fuel) along the productivity gradient. However, the full intermediate fire–productivity model across all world ecosystems remains to be validated. The entire globe, excluding Antarctica. To test the intermediate fire–productivity hypothesis, we use the world ecoregions as a spatial unit and, for each ecoregion, we compiled remotely sensed fire activity, climate, biomass and productivity information. The regression coefficient between monthly MODIS fire activity and monthly maximum temperature in each ecoregion was considered an indicator of the sensitivity of fire to high temperatures in the ecoregion. We used linear and generalized additive models to test for the linear and humped relationships. Fire occurs in most ecoregions. Fire activity peaked in tropical grasslands and savannas, and significantly decreased towards the extremes of the productivity gradient. Both the sensitivity of fire to high temperatures and above-ground biomass increased monotonically with productivity. In other words, fire activity in low-productivity ecosystems is not driven by warm periods and is limited by low biomass; in contrast, in high-productivity ecosystems fire is more sensitive to high temperatures, and in these ecosystems, the available biomass for fires is high. The results support the intermediate fire–productivity model on a global scale and suggest that climatic warming may affect fire activity differently depending on the productivity of the region. Fire regimes in productive regions are vulnerable to warming (drought-driven fire regime changes), while in low-productivity regions fire activity is more vulnerable to fuel changes (fuel-driven fire regime changes).
Ectomycorrhizal symbiosis is omnipresent in boreal forests, where it is assumed to benefit plant growth. However, experiments show inconsistent benefits for plants and volatility of individual partnerships, which calls for a re-evaluation of the presumed role of this symbiosis.
We reconcile these inconsistencies by developing a model that demonstrates how mycorrhizal networking and market mechanisms shape the strategies of individual plants and fungi to promote symbiotic stability at the ecosystem level.
The model predicts that plants switch abruptly from a mixed strategy with both mycorrhizal and nonmycorrhizal roots to a purely mycorrhizal strategy as soil nitrogen availability declines, in agreement with the frequency distribution of ectomycorrhizal colonization intensity across a wide-ranging data set. In line with observations in field-scale isotope labeling experiments, the model explains why ectomycorrhizal symbiosis does not alleviate plant nitrogen limitation. Instead, market mechanisms may generate self-stabilization of the mycorrhizal strategy via nitrogen depletion feedback, even if plant growth is ultimately reduced.
We suggest that this feedback mechanism maintains the strong nitrogen limitation ubiquitous in boreal forests. The mechanism may also have the capacity to eliminate or even reverse the expected positive effect of rising CO2 on tree growth in strongly nitrogen-limited boreal forests.
Fungi are essential components of all ecosystems in roles including symbiotic partners, decomposers and nutrient cyclers and as a source of food for vertebrates and invertebrates. Fire changes the environment in which fungi live by affecting soil structure, nutrient availability, organic and inorganic substrates and other biotic components with which fungi interact, particularly mycophagous animals. We review the literature on fire and fungi in Australia, collating studies that include sites with different time since fire or different fire regimes. The studies used a variety of methods for survey and identification of fungi and focussed on different groups of fungi, with an emphasis on fruit-bodies of epigeal macrofungi and a lack of studies on microfungi in soil or plant tissues. There was a lack of replication of fire treatment effects in some studies. Nevertheless, most studies reported some consequence of fire on the fungal community. Studies on fire and fungi were concentrated in eucalypt forest in south-west and south-eastern Australia, and were lacking for ecosystems such as grasslands and tropical savannahs. The effects of fire on fungi are highly variable and depend on factors such as soil and vegetation type and variation in fire intensity and history, including the length of time between fires. There is a post-fire flush of fruit-bodies of pyrophilous macrofungi, but there are also fungi that prefer long unburnt vegetation. The few studies that tested the effect of fire regimes in relation to the intervals between burns did not yield consistent results. The functional roles of fungi in ecosystems and the interactions of fire with these functions are explained and discussed. Responses of fungi to fire are reviewed for each fungal trophic group, and also in relation to interactions between fungi and vertebrates and invertebrates. Recommendations are made to include monitoring of fungi in large-scale fire management research programs and to integrate the use of morphological and molecular methods of identification. Preliminary results suggest that fire mosaics promote heterogeneity in the fungal community. Management of substrates could assist in preserving fungal diversity in the absence of specific information on fungi.
Ectomycorrhizal fungal diversity in Quercus ilex Mediterranean woodlands: variation among sites and over soil depth profiles in hyphal exploration types, species richness and community composition Abstract Understanding the factors underlying the distribu-tion of biodiversity is a challenging issue in ecology. Here, we examined the distribution patterns of ectomycorrhizal fungal diversity across the soil profile in three Quercus ilex forests. Contact exploration type strongly dominated at all sites, but was most prevalent in the upper, organic-rich soil layers. At each site, three quarters of the ectomycorrhizal tips and 59 % of taxa were restricted to the ten first centimeters of the soil profile. The relative abundance of the dominant family Russulaceae increased with increasing soil depth. Species composition varied significantly among sites, with most species being rare. Species that occurred in only one of the three sites accounted for 78.9 % of all species, and 57.3 % of species were represented by a single ECM root tip. Our results suggest that (i) rare species at both local and regional scales contribute to the highly diverse fungal as-semblages in Mediterranean forests and (ii) multi-sites stud-ies including the whole soil profile are needed to provide comprehensive overviews of the taxonomic and functional diversities of ectomycorrhizal communities.
Relationships between the flammability properties of a given plant and its chances of survival after a fire still remain unknown. We hypothesize that the bark flammability of a tree reduces the potential for tree survival following surface fires, and that if tree resistance to fire is provided by a thick insulating bark, the latter must be few flammable. We test, on subalpine tree species, the relationship between the flammability of bark and its insulating ability, identifies the biological traits that determine bark flammability, and assesses their relative susceptibility to surface fires from their bark properties. The experimental set of burning properties was analyzed by Principal Component Analysis to assess the bark flammability. Bark insulating ability was expressed by the critical time to cambium kill computed from bark thickness. Log-linear regressions indicated that bark flammability varies with the bark thickness and the density of wood under bark and that the most flammable barks have poor insulating ability. Susceptibility to surface fires increases from gymnosperm to angiosperm subalpine trees. The co-dominant subalpine species Larix decidua (Mill.) and Pinus cembra (L.) exhibit large differences in both flammability and insulating ability of the bark that should partly explain their contrasted responses to fires in the past.
Wildfires are a pervasive disturbance in boreal forests, and the frequency and intensity of boreal wildfires is expected to increase with climate warming. Boreal forests store a large fraction of global soil organic carbon (C), but relatively few studies have documented how wildfires affect soil microbial communities and soil C dynamics. We used a fire chronosequence in upland boreal forests of interior Alaska with sites that were 1, 7, 12, 24, 55, ~90, and ~100 years post-fire to examine the short- and long-term responses of fungal community composition, fungal abundance, extracellular enzyme activity, and litter decomposition to wildfires. We hypothesized that post-fire changes in fungal abundance and community composition would constrain decomposition following fires. We found that wildfires altered the composition of soil fungal communities. The relative abundance of ascomycetes significantly increased following fire whereas basidiomycetes decreased. Post-fire decreases in basidiomycete fungi were likely attributable to declines in ectomycorrhizal fungi. Fungal hyphal lengths in the organic horizon significantly declined in response to wildfire, and they required at least 24 years to return to pre-fire levels. Post-fire reductions in fungal hyphal length were associated with decreased activities of hydrolytic extracellular enzymes. In support of our hypothesis, the decomposition rate of aspen and black spruce litter significantly increased as forests recovered from fire. Our results indicate that post-fire reductions in soil fungal abundance and activity likely inhibit litter decomposition following boreal wildfires. Slower rates of litter decay may lead to decreased heterotrophic respiration from soil following fires and contribute to a negative feedback to climate warming.
We synthesize existing sedimentary charcoal records to reconstruct Holocene fire history at regional, continental and global scales. The reconstructions are compared with the two potential controls of burning at these broad scales – changes in climate and human activities – to assess their relative importance on trends in biomass burning. Here we consider several hypotheses that have been advanced to explain the Holocene record of fire, including climate, human activities and synergies between the two. Our results suggest that 1) episodes of high fire activity were relatively common in the early Holocene and were consistent with climate changes despite low global temperatures and low levels of biomass burning globally; 2) there is little evidence from the paleofire record to support the Early Anthropocene Hypothesis of human modification of the global carbon cycle; 3) there was a nearly-global increase in fire activity from 3 to 2 ka that is difficult to explain with either climate or humans, but the widespread and synchronous nature of the increase suggests at least a partial climate forcing; and 4) burning during the past century generally decreased but was spatially variable; it declined sharply in many areas, but there were also large increases (e.g., Australia and parts of Europe). Our analysis does not exclude an important role for human activities on global biomass burning during the Holocene, but instead provides evidence for a pervasive influence of climate across multiple spatial and temporal scales.
doi: 10.1890/ES11-00345.1
Fire, the primary natural disturbance factor in Fennoscandian boreal forests, is considered to have exerted major selection pressure on most boreal forest organisms. However, recent studies show that few ectomycorrhizal (EM) fungi appear to have evolved post-fire adaptations, no succession of EM fungi following fire is apparent after low intensity fires, and only two EM fungal taxa exclusively fruit at post-fire conditions. In this paper I review the present knowledge of effects of forest fire on EM fungal communities in Fennscandian boreal forests, put into perspective by a comparison from other pans of the world. Characteristically, these boreal forests consist of less than a handful of tree species, e.g. Scots pine and Norway spruce, while the below ground communities of EM fungi is impressively species rich with presently more than 700 known taxa. Commonly, forest fires in Fennoscandia have been of low intensity, with a considerable portion of the trees surviving and the organic humus layer partly escaping combustion. Hence, EM fungi appear to largely have evolved under conditions characterised by a more or less continuous presence of their hosts. In fact, the composition of EM fungi within a forest appear be more variable due to spatial variation than due to wildfire. However, in areas with high intensity burns and high tree mortality, most EM fungi may locally be killed. Thus, the legacy of EM fungi following wildfire depends on the survival of trees, which determine the potential for mycorrhizal growth, and the combustion and heating of the organic soil, which directly correlate to mortality of mycorrhizas. The questions if and to what degree fires may be of significance for yet unidentified spatiotemporal dynamics of EM fungal populations and communities are discussed. Recent experiments indicate a few EM fungi are favoured by high intensity burn conditions whereas others disappear. The consequences of wildfires in temperate conifer forests differ considerably from those in boreal forests. Wildfires in temperate conifer forests are typically high intensity stand-replacing fires that cause a total combustion of organic layers. Subsequently, pre-fire EM fungal communities are largely eradicated and a succession of post-fire EM fungi is initiated.
The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference dataset, and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here we report on progress in these regards through further development of the UNITE database (http://unite.ut.ee) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g., Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third-party annotation effort. We introduce the term “species hypothesis” (SH) for the taxa discovered in clustering on different similarity tresholds (97-99%). An automatically or manually designated sequence is chosen to represent each such species hypothesis. These reference sequences are released (http://unite.ut.ee/repository.php) for use by the scientific community in, e.g., local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new web-based sequence management system in UNITE.This article is protected by copyright. All rights reserved.
In a simulation model, the relative advantage of negative versus positive allometry of defense, that is, early versus delayed defensive investment, depends on the forms of the relationships between body size and growth, body size and mortality deterrence, and defense size and mortality deterrence. Positive allometry is favored by strongly sigmoidal growth, a strongly convex body-size/deterrence relationship, and a concave defense-size/deterrence relationship. Rapid early growth, a weakly convex body-size/deterrence relationship, and a convex defense-size/deterrence relationship favor negative allometry. The model is tested by comparing, among Pinus and Quercus species, measured intraspecific bark allometry with a predicted ranking of bark allometry along the negative-positive continuum. The ranking is based on the forms of body-size/deterrence and defense-size/deterrence relationships expected in each species' typical habitat given the fire regime and canopy type. This predicted ranking of bark allometry is significantly correlated with measured bark allometry. Negative bark allometry and thick sapling bark are associated with habitats characterized by frequent low-intensity fire and relatively open canopies. Fire-resilient Pinus spp. and species of infrequently burned, closed-canopy forests tend to have positive bark allometry and thin sapling bark.
Patterns of fungal spore dispersal affect gene flow, population structure and fungal community structure. Many Basidiomycota produce resupinate (crust-like) basidiocarps buried in the soil. Although spores are actively discharged, they ofte