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•We studied the effect of fire prevention treatments on soil fungal communities inhabiting scrublands.•Soil fungal community was profiled using high-throughput sequencing of fungal ...markers.•Site differences exerted stronger effect than fire prevention treatments on soil fungal communities.•Controlled fire and 100% clearing decreased the relative proportions of ectomycorrhizal species.•50% cleared treatments may decrease the risk of fire while maintaining the fungal communities.
Cistus ladanifer scrublands are widely distributed in the Mediterranean basin and represent an early stage of secondary succession following major disturbances (e.g., fire). This vegetation type often establishes on disturbed and poor soils, thereby improving soil stability in stress-prone environments. Fire prevention treatments in these scrublands are often recommended to decrease the risk of wildfires, but the effect of these treatments on associated soil fungi is not known. We studied the effect of distinct fire prevention treatments on soil fungal communities associated with C. ladanifer scrublands soils. We used Illumina MiSeq sequencing of the ITS1 region on soil samples taken after distinct fire prevention treatments that were performed in 27 plots belonging to a long-term experiment. Recent fire prevention treatments did not affect overall fungal community composition nor fungal diversity; however, when analyzing the community according to the functional guilds, the relative abundance of ectomycorrhizal species was significantly lower in burned and 100% cleared plots, compared with control and 50% cleared plots. In contrast, site history affected fungal community composition and richness to a greater extent than the fire prevention treatments. Our results show a higher susceptibility of ectomycorrhizal species to recent high-intensity fire prevention treatments, whereas fire prevention treatments of medium intensity may reduce the risk of wildfire and maintain the soil fungal community.
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•Thick clay-silty Luvisols in the bottom of dolines have high SOC storage capacity.•Past agricultural land-use presents long-term impact on SOC stock in dolines.•Succession plots in ...dolines show the highest SOC storage capacity (130 t/ha).•Soil organic carbon stock in dolines was double the amount on the levelled plateau.
The soil organic carbon (SOC) was determined in soils of enclosed karst depressions (dolines) (NW Dinaric Mts.) to define their potential for organic carbon sequestration. SOC was measured in the forest, succession (scrubland), and grassland plots at the bottom of dolines at four depths (0–40 cm) and for 40 cm soil layer SOC stock was calculated. We demonstrated that the prevailing fine soil fractions, the C/N ratio and soil thickness play a positive role in the storage capacity of SOC in dolines regardless land use type. Grasslands have the lowest SOC storage capacity (106 t/ha/40 cm), while the highest SOC storage capacity is in succession plots (130 t/ha/40 cm). The last are covered by shrub communities dominated by Prunus spinosa, forming dense communities, and are typical of abandoned croplands or meadows that have been impacted by high levels of nutrients during cultivation phase. At this stage, there is no additional nutrient input in studied plots, which lowers the nutrient content and increases the C/N ratio. C/N ratio is the highest in the forest, where SOC stock capacity is 116 t/ha/40 cm. Given the trend towards the abandonment of agricultural land at Kras Plateau (SW Slovenia), we can expect more overgrowth of dolines, and thus an increase in carbon stocks and stabilization of organic carbon in forest soils. In contrary, we noticed the alarming decrease in grasslands and increase in urban land. The SOC storage in 2020 was for 12,538 t/ha/40 cm lower than in 2002. Although grasslands showed the lowest SOC storage, their contribution to total SOC storage in dolines is very important. Since there is a lack of studies on carbon stocks in doline soils, our research is of great importance and a novelty and gives an important background for further research on SOC stock in karst landscapes worldwide.
•Junipers shrub dieback and mortality triggered by drought are understudied.•We compared growth and isotopes of living vs. dead junipers in two different sites.•Growth and isotopes showed ...site-specific patterns in living and dead junipers.•Growth was constrained by warm-dry summer conditions enhancing evapotranspiration.•Growth statistics were not robust early-warning signals of impending shrub death.
Drought-induced dieback episodes are globally reported among forest ecosystems but they have been understudied in scrublands. Chronically-stressed individuals are supposed to be more vulnerable prior to drought which triggers death. We analyzed drought-triggered dieback and mortality events affecting Mediterranean Juniperus phoenicea scrublands in two sites with contrasting climate and soil conditions located in Spain. We characterized the radial growth patterns of coexisting living and dead junipers, including the calculation of growth statistics used as early-warning signals, quantified growth response to climate, and analyzed the wood C and O isotope discrimination. In the inland, continental site with rocky substrates (Yaso), dead junipers grew less than living junipers about three decades prior to the dieback started in 2016. However, in the coastal, mild site with sandy soils (Doñana), dead junipers were smaller but grew more than living junipers about two decades before the dieback onset in 2005. The only common patterns between sites were the higher growth coherence in both living and dead junipers prior to the dieback, and the decrease in growth persistence of dead junipers. Cool and wet conditions in the prior winter and current spring, and cool summer conditions enhanced juniper growth. In Doñana, growth of living individuals was more reduced by warm July conditions than in the case of dead individuals. Higher δ13C values in Yaso indicate also more pronounced drought stress. In Yaso, dead junipers presented lower δ18O values, but the opposite occurred in Doñana suggesting different changes in stomatal conductance prior to death. Warm summer conditions enhance evapotranspiration rates and trigger dieback in this shallow-rooted species, particularly in sites with a poor water-holding capacity. Chronic, slow growth is not always a reliable predictor of drought-triggered mortality.
Semi-arid and arid regions account for >40 % of the land area worldwide and provide food resources for the world. Nutrient management by farmer's practices, such as fertilization, improves crop ...production in semi-arid and arid regions, but this can also affect the composition and function of the soil microbial communities. Therefore, in this research, we have examined the composition of the microbial community and biogeochemical cycling genes in arid soil, subjected to nutrient management by farmer's practices, using high-throughput sequencing and a quantitative-PCR-based chip, Quantitative microbial element cycling (QMEC). Proteobacteria and Acidobacteriota, and Ascomycota dominated the composition of bacterial and fungal communities, respectively. Scrubland soils without nutrient management possessed the lowest Chao1 richness and Shannon diversity of the bacterial community but showed higher average Shannon diversity of the fungal community. Acidobacteriota and Gemmatimonadota, copiotrophic members, were found to have a higher percentage in nutrient-managed soils (cotton, fruit, and vegetables) than the scrubland soils. However, Actinobacteria, autochthonous bacteria, were found to have higher relative abundance in soils from the scrubland than from cotton, fruits, and vegetables. Besides, scrubland soils had a higher relative abundance of Glomeromycota (arbuscular mycorrhizal fungi) to support plant growth in the arid and oligotrophic soils. Vegetable soil microbial communities exhibited a higher potential for biogeochemical cycling than soils used for other vegetation types. In soils from cotton and fruits, the bacterial community was more sensitive to soil properties than the fungal community. Nutrients strongly affected the composition of bacterial and fungal communities in soils from vegetables, while salinity drove the microbial communities in scrubland soils. Our results suggest that vegetation types determined the distinct biodiversity patterns of the microbiota (bacteria and fungi) and associated biogeochemical cycling genes in arid soils.
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•Distinct patterns of bacterial and fungal communities depended on vegetation types.•Nutrients play a critical role in shaping microbial communities in vegetable soils.•Salinity was the main factor driving microbial communities in scrubland soils.•Cotton and vegetable soils exhibited distinct patterns of nitrogen cycling genes.•Vegetable soil microbial community had higher potential for biogeochemical cycling.
Climate dictates wildfire activity around the world. But East and Southeast Asia are an apparent exception as fire-activity variation there is unrelated to climatic variables. In subtropical China, ...fire activity decreased by 80% between 2003 and 2020 amid increased fire risks globally. Here, we assessed the fire regime, vegetation structure, fuel flammability and their interactions across subtropical Hubei, China. We show that tree basal area (TBA) and fuel flammability explained 60% of fire-frequency variance. Fire frequency and fuel flammability, in turn, explained 90% of TBA variance. These results reveal a novel system of scrubland–forest stabilized by vegetation–fire feedbacks. Frequent fires promote the persistence of derelict scrubland through positive vegetation–fire feedbacks; in forest, vegetation–fire feedbacks are negative and suppress fire. Thus, we attribute the decrease in wildfire activity to reforestation programs that concurrently increase forest coverage and foster negative vegetation–fire feedbacks that suppress wildfire.
Vegetation-fire feedbacks in Subtropical China. Display omitted
•A novel system of scrubland–forest stabilized by vegetation–fire feedbacks.•The feedbacks are positive and promote frequent fire in scrubland.•The feedbacks are negative and suppress fire in forest.
Controlled fire effect on nutrients and physico-chemical properties of soil was investigated after a span of one year of controlled fire under four land uses viz. chir pine forest (Pinus roxburghii), ...grassland, scrubland and non-fire site in chir pine (control). In March 2018, a controlled fire was caused, and soil samples were taken after one year of burning at different soil depths (viz. 0-5 cm, 5-10 cm and 10-15 cm). The experiment consisted of five replications in factorial randomized block design. The results revealed that in comparison to pre-fire assessment, available nitrogen, phosphorus and potassium slightly increased, whereas, soil organic carbon decreased slightly in post-fire assessment. The soil pH, electrical conductivity, bulk density and soil texture did not show any significant change after one year of burning. The study concludes that controlled fire did not cause any drastic fluctuations in nutrients and physico-chemical properties of soil and can be used as an effective management practice for combating the negative effects of wildfire on soil.
Phenological segregation among species in a community is assumed to promote coexistence, as using resources at different times reduces competition. However, other unexplored nonalternative mechanisms ...can also result in a similar outcome. This study first tests whether plants can redistribute nitrogen (N) among them based on their nutritional temporal demand (i.e. phenology). Field
N labelling experiments showed that
N is transferred between neighbour plants, mainly from low N-demand (late flowering species, not reproducing yet) to high N-demand plants (early flowering species, currently flowering-fruiting). This can reduce species' dependence on pulses of water availability, and avoid soil N loss through leaching, having relevant implications in the structuring of plant communities and ecosystem functioning. Considering that species phenological segregation is a pervasive pattern in plant communities, this can be a so far unnoticed, but widely spread, ecological process that can predict N fluxes among species in natural communities, and therefore impact our current understanding of community ecology and ecosystem functioning.
Entre las Nyctaginaceae, Mirabilis se caracteriza por tener inflorescencias cimosas e involucros de 5 brácteas connadas y acrescentes en fruto, subyacentes a 1-3 flores. Con 55-57 especies, es uno de ...los géneros más diversos dentro de la familia. El objetivo de este trabajo fue analizar la diversidad de Mirabilis en México, presentar el tratamiento taxonómico de las especies, una clave de identificación, datos de hábitat, fenología y mapas de distribución. Se presenta la sinonimia, se designa el lectotipo para Mirabilis aggregata, M. sanguinea y M. urbani. De acuerdo con los ejemplares de herbario estudiados y datos analizados, México es el país con mayor diversidad del género con 31 especies, de las cuales 14 son endémicas. Mirabilis glabrifolia, M. jalapa y M. viscosa tienen la mayor distribución, mientras que M. calophlebia, M. hintoniorum, M. nesomii y M. urbani son las más restringidas. La mayoría de las especies se encuentra en matorral xerófilo y bosque tropical caducifolio; en cuanto a provincias biogeográficas, se encuentran principalmente en el Altiplano Norte (Chihuahuense), Altiplano Sur y Costa del Pacífico. M. melanotrichia es la especie que se encuentra a mayor altitud.
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•Right mixes of urban green-blue spaces could promote different physical exercises.•More walked in areas higher in both forest and scrub cover.•Walking frequency increased with ...managed vegetation cover.•Team-sports uptake and frequency grew with managed open-canopy vegetation cover.•Individual exercise frequency rose with higher water-and-open-greenery and forest-and managed-treescape cover.
Growing recognition of nature’s benefits to many aspects of human wellbeing has prompted the incorporation of both urban green and blue natural outdoor environments (NOEs) into cities. Amongst the many purposes of NOEs, promotion of physical exercise has been garnering interest, given the increasingly sedentary lifestyles of urban dwellers. However, studies rarely consider how different types of NOEs, let alone the combination of them, might affect the type and frequency of physical exercise conducted by urban residents. We use Singapore, a highly urbanised tropical nation with a considerable number of NOEs, as a case-study to address these gaps. We used a market research survey (n = 1519), geographic information systems, and generalised linear regression models to investigate the relationship between residential NOE cover, exercise-influencing sociodemographic factors, and outdoor exercise choice (i.e., if respondents exercised or not) and frequency of four types of physical exercises: walking, individual-based, team-sports, and overall exercise. For exercise choice, more people walked in areas with higher forest and scrub cover, and less in areas with just scrub. Less conducted individual-based exercise in areas with high unmanaged vegetation cover, and more conducted team-sports in areas with higher open-canopy managed vegetation cover. Amongst those who engaged in these exercises, managed vegetation cover is positively correlated with walking (open- and closed-canopy combined) and team-sports (open-canopy) frequency. Individual-based exercise frequency rose in areas with a mix of high open-canopy managed vegetation and blue space cover within 250 m from one’s home, and a mix of high managed treescape and forest cover 500 m from one’s home. Findings suggest that a specific mix of NOEs can promote the participation of different types of physical exercise. Integrating the right NOE types and combinations into urban residential spaces may thus help to mitigate sedentary lifestyles, boosting public health outcomes in city populations.
Our knowledge of the impact of landscape fragmentation on gene flow patterns is mainly drawn from tropical and temperate ecosystems, where landscape features, such as the distance of a tree to the ...forest edge, drive connectivity and mating patterns. Yet, the structure of arid and semiarid plant communities – with open canopies and a scattered distribution of trees – differs greatly from those that are well‐characterized in the literature. As a result, we ignore whether the documented consequences of landscape fragmentation on plant mating and gene flow patterns also hold for native plant communities in arid and semiarid regions. We investigated the relative contribution of plant traits, pollinator activity, and individual neighbourhood in explaining variation in mating and gene flow patterns of an insect‐pollinated semiarid arborescent shrub, Ziziphus lotus, at three sites embedded in highly altered agriculture landscapes. We used 14 SSRs, seed paternity analyses, and individual mixed effect mating models (MEMMi) to estimate the individual mating variables and the pollen dispersal kernel at each site. Individual spatial location, flower density, and floral visitation rate explained most of the variation of mating variables. Unexpectedly, individual correlated paternity was very low and shrubs surrounded by the most degraded matrix exhibited an increased fraction of pollen immigration and a high effective number of pollen donors per mother shrub. Overall, our results reveal that an active pollinator assemblage ensures highly efficient mating, and maintains pollen‐mediated gene flow and notable connectivity levels, even in highly altered landscapes, potentially halting genetic isolation within and between distant sites.
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