Early Stages Of Secondary Succession Research Articles

Influence of the Alien Herbaceous Plant <i>Solidago gigantea</i> on the Early Stages of Secondary Succession in an Abandoned Cultivated Field in Obihiro City, Hokkaido

Influence of the Alien Herbaceous Plant <i>Solidago gigantea</i> on the Early Stages of Secondary Succession in an Abandoned Cultivated Field in Obihiro City, Hokkaido

Aboveground carbon accumulation by second‐growth forests after deforestation in Hawai'i

Successional processes ultimately determine and define carbon accumulations in forested ecosystems. Although primary succession on wholly new substrate occurs across the globe, secondary succession, often following storm events or anthropogenic disturbance, is more common and is capable of globally significant accumulations of carbon (C) at a time when offsets to anthropogenic carbon dioxide (CO2 ) emissions are critically needed. In Hawai'i, prior studies have investigated ecosystem development during primary succession on lava flows, including estimates of C mass accumulation. Yet relatively little is known regarding secondary succession of Hawaii's native forests, particularly regarding C mass accumulation. Here we documented aboveground C mass accumulation by native- and nonnative-dominated second-growth forests following deforestation of mature native lowland rainforests in the Puna District of Hawai'i Island. We characterized species composition and stand structure of three distinct successional forest stand types: those dominated by the native tree, Metrosideros polymorpha ('Ōhi'a), and those dominated by invasive nonnative trees, Falcataria moluccana (albizia) and Psidium cattleianum (strawberry guava). We compared M. polymorpha-dominated and F. moluccana-dominated second-growth forests to adjacent mature M. polymorpha-dominated forests as well as young M. polymorpha-dominated forests undergoing initial stages of primary succession on 36-years-old lava fields. Aboveground carbon density (ACD) values of mature primary forest stands (171 Mg/ha) were comparable to those of mature continental tropical forests. M. polymorpha-dominated second-growth stands attained nearly 50% of ACD values of mature primary forests after less than 30 years of post-disturbance succession and exhibited aboveground carbon accumulation rates of ~3 Mg C·ha-1 ·year-1 . Such rates were comparable to those of second-growth forests in continental tropics. Rates of ACD accumulation by second-growth forests dominated by nonnative F. moluccana stands were similar, or slightly greater than, those of M. polymorpha-dominated stands. However, M. polymorpha individuals were virtually absent from stands dominated by either P. cattleianum or F. moluccana. Taken together, results demonstrated that re-establishment and rapid accumulation of C mass by M. polymorpha stands during secondary succession is certainly possible, but only where populations of nonnative species have not already colonized areas during early stages of secondary succession.

Response of surface-soil quality to secondary succession in karst areas in Southwest China: Case study on a limestone slope

Karst areas are fragile ecological environments facing serious soil quality problems. It is crucial to understand the surface-soil quality for ensuring the secondary succession of vegetation. In this study, four plots located on the same hill slope were selected, representing the four secondary succession stages of arable land, grassland, shrubs, and secondary forest, respectively. The surface-soil quality during secondary succession is assessed using the minimum dataset method. The results show that secondary succession decreased soil bulk density and total potassium content (P < 0.05), whereas soil organic matter, saturated hydraulic conductivity, overall porosity, and total nitrogen increased (P < 0.05). However, pH and capillary porosity are relatively stable. Non-capillary porosity and total phosphorus content first decreased and then increased. In addition, the mean soil quality indices increased and the difference in surface-soil quality between stages decreased with vegetation succession (P < 0.05). Improvement in surface-soil quality is most obvious in the early stages of secondary succession, and natural vegetation restoration can solve the land degradation problem. This study is not only helpful in understanding the changes in surface-soil quality during the secondary succession but also provides a theoretical basis for selecting ecological restoration methods in karst regions.

The competitive mechanism between post-abandonment Chinese fir plantations and rehabilitated natural secondary forest species under an in situ conservation policy

During the past 30 years, the global forest area has been subject to a continuous increase in planted forests and a decline in natural forests, raising significant concerns about biodiversity protection. Once these plantations are abandoned due to changes in conservation or forest management policies, can they recover to the same state as natural forests during secondary succession? The key ecological processes supporting the stable coexistence or competitive elimination mechanisms between post-abandonment plantations and natural secondary forest tree species are still poorly understood and may be the decisive ecological processes driving secondary forest restoration. A 12-ha long-term forest plot was established in an abandoned Chinese fir plantation that has been protected under an in situ protection policy for 40 years. In total, 66,317 individual trees were stem mapped and identified at the species level, and the spatial survival strategies and species coexistence mechanisms between Chinese fir and natural secondary forest tree species were investigated. The results showed that the spatial survival strategy of Chinese fir could effectively trade off a high conspecific density-dependent mortality rate of individuals during the early stage of secondary succession for the long-term survival of the whole population, which promoted its dominance during later stages of succession. By contrast, although the higher survival rate and larger intraspecific aggregation scale of natural secondary forest individuals favored their survival during initial colonization, this spatial survival strategy might occur at the cost of neglecting suitable habitats and the loss of competitive advantages at the later stage of succession. Regarding interspecific competition, the asymmetric competition process further ensured the advantages of Chinese fir in individual size growth and increased the competitive advantage of Chinese fir over natural secondary forest tree species by exclusion through interspecific competition during the later secondary succession stage. Our results suggest that implementing a forest recovery program or an in situ protection policy based on post-abandonment monoculture plantations may involve great uncertainty about whether the goal can be achieved. Specifically, although this strategy could quickly increase forest coverage and restore the forest landscape, it may also create difficulties in restoring the forest to its original state.

A tetraploid Echinochloa with plagiotropic tillers: Its distribution and habitat in the northern part of the main island of Japan

AbstractAn annual Echinochloa with plagiotropic tillers (semi‐erect type) was found on a paddy levee in Miyagi prefecture in Japan. This semi‐erect type had tetraploid chromosome numbers (2n = 36) and would be expected to be E. oryzicola. However, its appearance was distinct from that of E. oryzicola. To collect seed samples and clarify its distribution and habitat, exploration and collection surveys were carried out in the northern part of Honshu, the main island of Japan in 2014, 2017, and 2018. Thirty‐two populations that were assumed to be the semi‐erect type were found and their mature seeds were collected. Based on the results of chromosome counts and growth form analyses, all of them were confirmed to be the semi‐erect type. The 32 populations were distributed in the prefectures of Aomori, Iwate, Akita, Miyagi, Yamagata, Fukushima, and Niigata, and located in paddy fields, abandoned paddy fields, paddy levees, roadsides, vacant land, and scree slopes. Our surveys indicated that the semi‐erect type grew in wet and dry disturbed habitats at an early stage of secondary succession including paddy fields in the northern part of the main island of Japan.

Resistance of the soil fungal communities to medium-intensity fire prevention treatments in a Mediterranean scrubland

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.

Root growth dynamics during recovery of tropical mountain forest in North-east India

Ever increasing pressures on tropical forests worldwide due to anthropogenic disturbances have greatly affected both above- and belowground functioning of these forests. While fine roots play major ecological roles in forests through assisting in nutrient and water uptake and returning elements to the soil environment, coarse roots play an important role in C sequestration. We studied changes in fine and coarse root biomass, production, turnover and carbon and nitrogen return to the soil in two regenerating forest stands (RFs) following stone-mining that were 5 years (RF-5) and 15 years (RF-15) post-disturbance compared with a natural forest stand (NF) in Mizoram, North-east India. Fine (§2 mm) and coarse root (2-10 mm) biomass differed significantly among the forest stands and ranged from 239 (RF-5) to 415 (NF) and 230 (RF-5) to 436 (NF) g m−2, respectively. Total root (fine + coarse) biomass increased during stand development but the proportion of very fine root (<0.5 mm) to total root production decreased. Fine root biomass decreased with increasing soil depth. Fine and total root biomass showed strong seasonal correlations with soil moisture, more so than for rainfall and temperature, whereas these relationships were less clear for the coarse root biomass. The amount of N (25–55 kg ha−1) and C (1.9–3.6 t ha−1) stored in root biomass increased with stand age with a corresponding increase in production and turnover of C and N to the soil. Disturbance to these tropical forests negatively affected root dynamics, influenced their spatio-temporal patterns, and reduced the production, amount and availability of nutrients returned to the soil along with a strong reduction in the root biomass carbon pool and sequestration in carbon residence time. We observed that root growth, especially fine roots, is dependent on abiotic variables, and plays a significant role in early stages of secondary succession by adding organic matter and nutrients through high turnover rates in these forests.

How does avian seed dispersal shape the structure of early successional tropical forests?

Abstract Frugivores shape plant communities via seed dispersal of fleshy‐fruited plant species. However, the structural characteristics that frugivores impart to plant communities are little understood. Evaluating how frugivores structure plant communities via the nonproportional use of available fruit resources is critical to understand the functioning of ecosystems where fleshy‐fruited plant species are dominant, such as tropical forests. We performed a seed‐addition field experiment to investigate how frugivorous birds shape the composition and richness of forests during early stages of secondary succession in cleared areas in Puerto Rico. The experiment tested whether the bird‐generated seed rain and the subsequent early successional plant communities were proportional representations of the fleshy‐fruited species that dominated the surrounding community. Experimental treatments consisted of patches with (a) seed‐additions by wild birds attracted to experimental patches with pole perches, (b) manual seed‐additions proportional to fruit abundance at the local scale (≤50 m from experimental plots) and (c) manual seed‐additions proportional to fruit abundance at the landscape scale (entire study site). Birds' seed‐additions differed in composition and abundance to expectations based on fruit availability at local and landscape scales. Treatments with seeds added by birds had the highest species richness in both the seed rain and the emergence stages despite how, on average, the monthly richness in the landscape‐scale treatment was double that of birds and the local‐scale treatment. This phenomenon was explained by the highest heterogeneity from the bird seed‐addition treatment across months, and the lowest seed per capita emergence rates in landscape treatments. Rather than reflecting relative fruit abundance, birds biased seed rain and per capita emergence towards a non‐random mixture of both small‐ and large‐seeded species, resulting in richer and distinct plant communities. Because frugivory and seed dispersal patterns depart from random encounters between frugivores and plants in communities, successional forests are characterized by an overrepresentation of proportionally rare plant species, and decreases in the dominance of many common species. Thus, for regenerating tropical forests, frugivory can function as mechanism that promotes persistence of rare plant species and their coexistence with more abundant plants. A plain language summary is available for this article.

Successional processes in agricultural mosaics in the eastern Amazon

Most tropical landscapes are mainly composed of dynamic mosaics involving multiple land uses. Different histories of land use management can lead to different successional paths. The aim of this study was to determine if there is a successional floristic gradient related to land use types and how these gradients change across three rural mosaics in Eastern Amazon. We also investigated what are the indicator species across mosaics and land use types and how they change through succession. Five sampling points were established in nine family farms at each mosaic. A detrended correspondence analysis was used to reveal the successional gradient. A multivariate regression tree was used to analyze differences in floristic composition between mosaics and land uses. Floristic similarity between land uses formed successional gradient at the mosaics, in which agricultural land uses represent the early stages of secondary succession and forests represent more advanced stages. Total number of species and total number of shade-tolerant species were correlated with advanced successional stages in all mosaics, but pioneer trees were also correlated with advanced stages in fragmented mosaics. Each mosaic had a distinct successional series due to different management approaches. Where the matrix was mainly composed of forest fragments and the human intervention period was shorter, land use types were more similar to one another as they were grouped into fewer successional stages. Thus, the floristic similarity between land use types appears as an indicator of successional advancement across the mosaics and help determine the regenerative capacity of those areas.

Ecology of Pioneer Species of early stages of Secondary succession I.

Ecology of Pioneer Species of early stages of Secondary succession I.

Biomass Accumulation and Net Primary Production during the Early Stage of Secondary Succession after a Severe Forest Disturbance in Northern Japan

Quantitative evaluations of biomass accumulation after disturbances in forests are crucially important for elucidating and predicting forest carbon dynamics in order to understand the carbon sink/source activities. During early secondary succession, understory vegetation often affects sapling growth. However, reports on biomass recovery in naturally-regenerating sites are limited in Japan. Therefore, we traced annual or biennial changes in plant species, biomass, and net primary production (NPP) in a naturally regenerating site in Japan after windthrow and salvage-logging plantation for nine years. The catastrophic disturbance depleted the aboveground biomass (AGB) from 90.6 to 2.7 Mg·ha−1, changing understory dominant species from Dryopteris spp. to Rubus idaeus. The mean understory AGB recovered to 4.7 Mg·ha−1 in seven years with the dominant species changing to invasive Solidago gigantea. Subsequently, patches of deciduous trees (mainly Betula spp.) recovered whereas the understory AGB decreased. Mean understory NPP increased to 272 g·C·m−2·year−1 within seven years after the disturbance, but decreased thereafter to 189 g·C·m−2·year−1. Total NPP stagnated despite increasing overstory NPP. The biomass accumulation is similar to that of naturally regenerating sites without increase of trees in boreal and temperate regions. Dense ground vegetation and low water and nutrient availability of the soil in the study site restrict the recovery of canopy-forming trees and eventually influence the biomass accumulation.

Структура и биопродуктивность растительных сообществ на ранней стадии вторичных сукцессий после сплошной рубки среднетаежных ельников Республики Коми

На территории Республики Коми отсутствуют материалы по биомассе и продукции растений как на вырубках, так и в молодняках на ранних стадиях их развития, поэтому нами начато изучение структуры, запасов и продукции насаждений на ранней стадии вторичных сукцессий растительности после промышленной рубки репрезентативных типов ельников на торфянисто-подзолисто-глееватых почвах. Постоянные пробные площади (ППП) в ельниках черничном влажном и долгомошно-сфагновом были заложены в 1978 г. сотрудниками отдела лесобиологических проблем Севера Института биологии Коми НЦ УрО РАН. На вырубке ельников с помощью методов, принятых в лесной таксации, в границах ППП пересчитаны деревья, учтен запас древесины деревьев недоруба и семенников, валежа и остолопа. Проведен сплошной перечет самосева и подроста. Фитомассу и прирост надземных частей древесных растений определяли методом модельных деревьев. На ППП проанализировано 20 модельных деревьев в ельнике черничном влажном и 23 в долгомошно-сфагновом, 10 модельных экземпляров подроста ели, 10 березы, 8 рябины. Такое количество модельных деревьев обеспечивает 10 % точности определения фитомассы древесного яруса. После рубки ельников средней тайги Республики Коми происходит изменение видового разнообразия растений фитоценозов, активно поселяются береза, рябина и ель. На вырубке ельников самосева и подроста насчитывается 6,8 – 8,3 тыс. экз./га. Запасы органического вещества растений составляют 66,1 – 85,9 т/га, размеры их годичной продукции — 3,9 – 4,6 т/га. Растения напочвенного покрова на вырубке являются эдификаторами и основными продуцентами (75 – 79 %) фитоценозов.

Changes in the ecological diversity of the forest population of ground beetles (Coleoptera, Carabidae) after deforestation and during the initial period of reforestation

The ecological structure of ground beetles was studied. Its dynamics during the migration of ground beetles from one habitat to another as a result of severe ecological disturbances caused by tree felling and subsequent reforestation was considered. Some regularities in the formation and development of a ground beetle community in the early stage of secondary succession at the felling site were determined. Further trends were revealed using the simplest indices of diversity, species, abundance, distribution, and dominance of species. The species richness of ground beetles at the site one year after felling increased from 28 to 41 species. It decreased to 36 species in four years. According to the ecological preference, the basis of the complex of ground beetles at the forest site before felling was formed by spring-breeding species. Four years after felling, the proportion of forest species decreased (from 73.4 to 65.7%) and the significance of forestmarsh and meadow-field species increased. The proportion of summer- and autumn-breeding species also increased. The species and quantitative composition of ground beetles at the site during the first year after felling was mostly determined by neighboring forests. As reforestation proceeded, a separate biocenosis developed at the felling site and the influence of the forests became lower. The proportion of summer- and autumnbreeding species increased. The species and quantitative composition of ground beetles at the felling site was mostly determined by the neighboring forest during the first year. A separate biocenosis developed at the felling site in the following years, and the influence exercised by the forest diminished.

Do heavy-metal grassland species survive under a Scots pine canopy during early stages of secondary succession?

The highly specialized flora of localities affected by former metal ore mining and metallurgy is endangered by succession or intentional afforestation all over Europe. Its last remnants therefore deserve our attention. We examined whether Scots pine encroaching on a heavy-metal grassland (Olkusz Zn-Pb mining area, S Poland) is outcompeting specialized herbaceous species, as has been observed elsewhere. Plant species composition and richness sampled at 124 plots were analysed in relation to pine stand parameters (canopy cover, stand age, stand basal area), abiotic environmental factors (e.g. soil properties) and spatial variables (e.g. plot coordinates). Plots were divided into three shading categories and compared in terms of vegetation and habitat parameters. Scots pine outcompeted several light-demanding species, leading to a decrease of total species richness and cover. Characteristic species of this grassland (Biscutella laevigata, Silene vulgaris) and some metal-tolerant plants were clearly insensitive to shading. For these early successional species, more important was the availability of microsites with shallow skeletal soil or bare subsoil. Tree stand parameters differently affected grassland vegetation: canopy cover caused primarily a compositional shift in the community, while stand age was the principal agent of decline in species richness. Scots pine increased the soil concentrations of available Ca and Mg, and negatively affected soil development (organic matter and mineral particle accumulation), which might be beneficial to some shade-tolerant grassland species. Maintaining the studied grassland’s present species richness and composition would require cutting woody plants less frequently than recommended for dry grasslands of non-metalliferous sites, and disturbing the soil surface.

ESTRUTURA, DIVERSIDADE E HETEROGENEIDADE DO ESTRATO REGENERANTE EM UM FRAGMENTO FLORESTAL URBANO APÓS 10 ANOS DE SUCESSÃO FLORESTAL

Este estudo visou avaliar a composição florística, a fitossociologia e a diversidade de espécies do estrato regenerante arbóreo de um pequeno fragmento (0,5 ha) de Floresta Estacional Semidecidual, após 10 anos de abandono, no perímetro urbano do município de Juiz de Fora, MG, Brasil. Os indivíduos da regeneração arbórea (altura ≥ 1 m e DAP &lt; 5 cm) foram amostrados em 25 parcelas aleatórias de 5 x 5 m. Foram amostrados 1224 indivíduos pertencentes a 40 espécies. Houve uma forte predominância (&gt; 90%) de espécies de estágios sucessionais iniciais (pioneiras e secundárias iniciais). Como reflexo da forte dominância ecológica observada, exercida principalmente pela elevada densidade das espécies Dalbergia nigra e Siparuna guianensis, o valor do índice de diversidade de espécies de Shannon (H’ = 2,38) foi muito inferior aos valores encontrados para fragmentos florestais maduros. Mesmo sendo um fragmento pequeno, isolado e em estágio inicial de sucessão secundária, análises multivariadas (agrupamento e DCA) evidenciaram a formação de grupos florísticos e uma forte diferenciação no arranjo das espécies, evidenciando a heterogeneidade típica de florestas tropicais. Embora apresente uma baixa diversidade, esse fragmento urbano tem funções ecológicas e sociais importantes para a região, que carece de áreas verdes para a conservação da flora nativa.AbstractStructure, diversity and heterogeneity of regeneration stratum in an urban forest fragment after 10 years of forest succession. This research aimed to evaluate the floristic composition, phytosociology and species diversity of the regenerating woody stratum of a small fragment (0.5 ha) of Semideciduous Forest, after 10 years of abandonment, in the municipality of Juiz de Fora, MG, Brazil. All woody individuals (height ≥ 1 m dbh &lt;5 cm) were sampled at 25 random plots of 5 x 5 m. We sampled 1224 individuals belonging to 40 species. There was a strong predominance (&gt; 90%) of species of early successional stages (pioneer and early secondary). Reflecting the strong observed ecological dominance, exercised primarily by the high density of the species Dalbergia nigra and Siparuna guianensis, species diversity value (Shannon index H '= 2.38) was much lower than the values found for mature forest fragments in this region. Although a small fragment, isolated and in early stages of secondary succession, the multivariate analysis (cluster and DCA) revealed the formation of distinct floristic groups and a strong differentiation in the arrangement of the species, showing the tropical forests typical heterogeneity. Although it has a low diversity, this urban fragment has ecological and social importance to the region, that present lack of green areas to conserve the native flora.Keywords: Phytosociology; multivariate analysis; gradient analysis; ecological groups.

Kelp canopy facilitates understory algal assemblage via competitive release during early stages of secondary succession.

Kelps are conspicuous foundation species in marine ecosystems that alter the composition of understory algal assemblages. While this may be due to changes in the competitive interactions between algal species, how kelp canopies mediate propagule supply and establishment success of understory algae is not well known. In Southern California, USA, Eisenia arborea forms dense kelp canopies in shallow subtidal environments and is associated with an understory dominated by red algal species. In canopy-free areas, however, the algal assemblage is comprised of mostly brown algal species. We used a combination of mensurative and manipulative experiments to test whether Eisenia facilitates the understory assemblage by reducing competition between these different types of algae by changes in biotic interactions and/or recruitment. Our results show Eisenia facilitates a red algal assemblage via inhibition of brown algal settlement into the canopy zone, allowing recruitment to occur by vegetative means rather than establishment of new individuals. In the canopy-free zone, however, high settlement and recruitment rates suggest competitive interactions shape the community there. These results demonstrate that foundation species alter the distribution and abundance of associated organisms by affecting not only interspecific interactions but also propagule supply and recruitment limitation.

Aboveground biomass and net primary production at an early stage of secondary succession after clear cutting of a deciduous broad-leaved forest

Aboveground biomass and net primary production at an early stage of secondary succession after clear cutting of a deciduous broad-leaved forest

The early stages of secondary succession after clear-cutting in a deciduous broad-leaved forest

The early stages of secondary succession after clear-cutting in a deciduous broad-leaved forest

High Abundance and Role of Antifungal Bacteria in Compost-Treated Soils in a Wildfire Area

Compost has been widely used in order to promote vegetation growth in post-harvested and burned soils. The effects on soil microorganisms were scarcely known, so we performed the microbial analyses in a wildfire area of the Taebaek Mountains, Korea, during field surveys from May to September 2007. Using culture-dependent and -independent methods, we found that compost used in burned soils influenced a greater impact on soil fungi than bacteria. Compost-treated soils contained higher levels of antifungal strains in the genera Bacillus and Burkholderia than non-treated soils. When the antifungal activity of Burkholderia sp. strain O1a_RA002, which had been isolated from a compost-treated soil, was tested for the growth inhibition of bacteria and fungi isolated from burned soils, the membrane-filtered culture supernatant inhibited 19/37 fungal strains including soil fungi, Eupenicillium spp. and Devriesia americana; plant pathogens, Polyschema larviformis and Massaria platani; an animal pathogen, Mortierella verticillata; and an unidentified Ascomycota. However, this organism only inhibited 11/151 bacterial strains tested. These patterns were compatible with the culture-independent DGGE results, suggesting that the compost used in burned soils had a greater impact on soil fungi than bacteria through the promotion of the growth of antifungal bacteria. Our findings indicate that compost used in burned soils is effective in restoring soil conditions to a state closer to those of nearby unburned forest soils at the early stage of secondary succession.

Early-successional vegetation changes after roadside prairie restoration modify processes related with soil functioning by changing microbial functional diversity

Because of their rapidly changing vegetation dynamics and harsh environmental conditions, roadside prairies in semi-arid regions represent an exceptional study system in which to investigate the effects of plant-soil interactions on ecosystem functioning. We conducted a two-year field experiment on two roadside embankments in semi-arid central Spain differing in construction age to answer the following questions: (i) do commonly used restoration treatments (hydroseeding, fertilization and irrigation) affect soil microbial functional diversity and processes related to soil functioning (basal respiration, total N and P and in situ N availability rate)? (ii) what portion of plant effects on processes related to soil functioning is mediated indirectly by microbial functional diversity? Except for a small and negative irrigation effect on the microbial functional diversity in the three-year old site, the restoration treatments employed did not affect this variable. Fertilization increased plant diversity, an effect likely mediated by the enhanced soil nutrient availability with this treatment at early stages of secondary succession. In contrast, hydroseeding did not affect processes related to soil functioning. The total effect of the plant community on these processes was higher than that of the microbial functional diversity alone, suggesting that the studied slopes are to the greater extent regulated by plants. However, soil microbes are a key proximate influence in the system, as the indirect effects of plant community on soil functioning processes mediated by soil microbes represented 37e41% of the total plant effects observed. Our results indicate that the restoration of recently built slopes can potentially be improved with treatments that promote plant compositional shifts, such as fertilization, or alter soil function, such as the enhancement of soil microbial functional diversity. They also highlight that plant-soil interactions are an important process that can be manipulated for restoration purposes in early-successional stages, especially in nutrient-poor semi-arid ecosystems.