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Silvicultural management does not affect biotic communities in conifer plantations in the short-term: A multi-taxon assessment using a BACI approach
Abstract and Figures
Biodiversity maintenance is a key strategy for sustainable forestry in both above-ground and below-ground biotic communities. However, few studies applied continuous monitoring to analyse the responses of different taxonomic groups to silvicultural treatments. We studied the short-term effects of three silvicultural treatments (no thinning, thinning from below, and selective thinning) on taxonomic richness and composition in two Pinus nigra J.F. Arnold plantations in Tuscany (Italy). We conducted a 1 year before–3 years after control-impact (BACI) experiment with a complete randomized design and analysed the responses of five different taxonomic groups (bacteria, nematodes, microarthropods, mushrooms and vascular plants (overstorey and understorey), along with the patterns of different structural variables. The silvicultural treatments induced a sudden decrease of many parameters such as number of trees per hectare, basal area, and standing volume, with a direct impact on the Photosynthetic Active Radiation on the ground (PAR). Despite this, biological communities showed a high resistance to the tree thinning intensities. Indeed, none of the thinning treatments significantly affected the entire community in the short-term, neither regarding taxonomic richness nor composition. The different taxonomic groups showed a similar, low or null, sensitivity to forest management, and thus a high congruence in their responses.
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... Since different taxonomic communities can have contrasting responses to anthropogenic and environmental drivers, multi-taxonomic assessments are important for better understanding humans' impacts on biodiversity [45][46][47]. Although vascular plants and springtails are recognized as effective biological indicators in agroecosystems [48,49], their combined response to agricultural management practices remains largely unexplored. ...
Agricultural practices significantly influence agroecosystem biodiversity, driving a growing focus on the development of environmentally sustainable management strategies. Olive (Olea europaea L.) is one of the most widely cultivated tree crops in the Mediterranean basin and other regions with a Mediterranean climate. In this study, we employed a split-plot design with whole plots arranged as a randomized complete block design (RCBD) to evaluate the effects of minimum tillage and the application of wood distillate to olive canopies on wild vascular plant and soil-dwelling springtail communities in a conventionally managed olive grove in central Italy. Biotic communities were sampled twice, in November and April. Tillage caused a marginally significant decrease of springtail species richness in April and significantly influenced the composition of both plant and springtail communities in April. All the plant species showed a decrease in abundance under tillage, whereas the abundance of springtail species responded to tillage in a species-specific way. Wood distillate had no effect on any community attribute in either season. Springtail total abundance was not affected by any treatment in either season. Our findings confirm that tillage practices affect the diversity of plant and springtail communities. Moreover, we had evidence that spring tillage may have more negative impacts on the studied communities with respect to autumn tillage. Besides, we suggest that the application of low-concentration wood distillate to olive canopies can be considered, in the short-term, a sustainable agricultural practice that does not negatively affect agroecosystem biodiversity.
... Several studies have investigated the application of long-term monitoring of select post-completion sites to evaluate the effects of mitigation measures on ecological corridors using before-after-control-impact analysis techniques to assess the effectiveness of biodiversity conservation policies and mitigation plans [12,13]. Additionally, several studies have utilized landscape connectivity, the incidence function model, and species distribution models to predict the impacts before and after development, providing foundational data for formulating appropriate mitigation plans within EIA [14,15]. ...
Rapid urbanization and development projects in Korea have posed significant threats to biodiversity; thus, effective mitigation measures are required to preserve natural habitats. Nevertheless, the factors underlying variations in mitigation measure effectiveness according to the disturbance level and surrounding environmental conditions have not been clarified. This study evaluated the effectiveness of mitigation measures implemented in environmental impact assessments (EIAs) of development projects in Korea, with a focus on their effectiveness with respect to the disturbance level and surrounding environmental conditions. A review of 288 EIA reports from selected projects that implemented all 10 mitigation measures classified according to the Wildlife Conservation Comprehensive Plan was conducted. Using the biodiversity tipping point framework, the effects of mitigation measures on biodiversity were categorized into four levels and analyzed. Analysis of variance and redundancy analysis were then performed to discern the variance in mitigation measure effectiveness in terms of the disturbance level, surrounding environment, and species. The results revealed significant variations in the effectiveness of mitigation measures depending on the surrounding environment and disturbance level. Linear projects exhibited a clear impact on various species as the disturbance level increased, whereas area-based projects did not exhibit such pronounced effects. All species demonstrated a negative relationship with development duration, development area, and distance from urban centers. Notably, avian and amphibian species showed a strong negative correlation with the digital elevation model while reptiles and mammals exhibited a strong positive relationship with pre-development biodiversity and distance from protected areas, respectively. Mitigation measures play a key role in alleviating the adverse effects of development projects; therefore, our findings indicate the need for spatially tailored mitigation plans to augment their effectiveness.
... In planted coniferous stands where conversion is planned in order to replace softwood species with native hardwoods, thinning is a powerful tool for the quick promotion of natural regeneration and increased tree biodiversity [75][76][77]. The magnitude of intervention can also be substantial, where up to 60% of pre-intervention biomass can be removed on one occasion for conversion purposes [78][79][80]. Furthermore, thinning in the coniferous forests of the Pacific Northwest in the USA led to increased richness, which also remained stable 17 years after the intervention and with the negligible appearance of invasive species [81]. ...
Purpose of Review Biodiversity is one of the most important features of forest ecosystems. One of the goals of Sustainable
Forest Management is to reduce biodiversity disturbance, which can occur as a consequence of timber harvesting. The aim
of this review was to define which silvicultural systems and forest operations can have an influence on forest tree biodiversity
by summarising the findings of nearly 60 papers published in the last ten years (2013–2022).
Recent Findings In natural forest ecosystems characterised by a high level of structural complexity, such as uneven-aged
tropical forests, selective logging and retention forestry are, in general, suitable forms of intervention that have a limited
impact on tree biodiversity. Forest operations, in particular, should be of low intensity and try to simulate as much as possible
small-scale natural disturbances. Thinning has proved to be a valid treatment for managing tree biodiversity. However,
it is important to shape the magnitude of thinnings according to the management aims. Limited removal is recommended
in interventions for maintaining the current structure, and more extensive removal is appropriate in cases when a change in
species composition is expected, e.g. in the conversion of planted coniferous stands to uneven-aged mixed or broadleaved
stands. In addition, coppicing is suitable for maintaining tree biodiversity due to its effectiveness in fostering the presence
of light-demanding tree species. Findings show that it is important to establish the right rotation age, considering that an
excessively short period between coppicing interventions can be detrimental to functional biodiversity.
Skid trails and landing sites represent suitable areas for the initial establishment of natural regeneration. However, generally,
the level of biodiversity on these sites declines with time as a consequence of soil compaction, thus highlighting the
importance of the forest infrastructure network planning.
Summary In uneven-aged tropical forests, selective logging and retention forestry are the most suitable options for maintaining
tree biodiversity. Thinning and coppicing help to manage biodiversity, whilst intensive thinning helps to change species
composition. Skid trails and landing sites can support natural regeneration. Recommendations and management options were
developed, as well as possible future research directions. The authors recommend that future studies should investigate how
much tree biodiversity depends on different levels of harvesting technology applied within the same silvicultural treatment.
... The relationships between the space occupied by the canopy and other fundamental features of forest ecosystems have been often investigated in literature and mainly aimed at evaluating the levels of animal and plant biodiversity (Torras and Saura 2008;Maccherini et al. 2021), measuring the degree of inter and intra-specific competition (Page and Cameron 2006;Fichtner et al. 2013), predicting the mechanical stability of the trees (Wang et al. 1998;Marchi et al. 2017) and assessing the flame speed in the event of fire (Martín Santafé et al. 2014;Kim et al. 2016). The singletree crown size and therefore its photosynthetic capacity, is one of the main indicators of the effects of silvicultural treatments on the competition between trees in forest stands (Cabon et al. 2018). ...
Key message
The crown volume of
Pinus nigra
trees can be modelled as a function of the total crown length and the crown radius at crown base to support forest management practices.
ContextThe crown volume of trees is rarely considered in forest management practices and is often approximated to a simple cone or paraboloid whose volume can be broadly derived from costly measurements.AimsWe developed two equations to predict single-tree crown volumes for Pinus nigra plantations in Italy based on the analysis of a database with 3578 trees.Methods
Two key crown parameters (total length of the crown and crown radius at crown base) were here modelled using directly measurable mensurational data using Generalise Additive Mixed-effect Model. Afterwards, two functions were then proposed to predict single-tree crown volumes.ResultsThe fitted models were statistically significant and explaining 57.6% for crown radius at crown base and 87.1% for crown length of the total variance. The power model for single-tree crown volumes calculation showed a mean absolute error around 4.1 m3 for the upper portion of the crown and 12.1 m3 for the lower part for a mean absolute relative error of 12.5% and 32.0% respectively for a global value of 16.4%.Conclusion
Single-tree and stand-level data are fundamental to balance forest management trajectories. The provided functions may be used in external dataset to derive indication on the single-tree or stand-level crown volume to be used as indicators of ground coverage.
Cistus scrublands are pyrophytic ecosystems and occur widely across Mediterranean regions. Management of these scrublands is critical to prevent major disturbances, such as recurring wildfires. This is because management appears to compromise the synergies necessary for forest health and the provision of ecosystem services. Furthermore, it supports high microbial diversity, opening questions of how forest management practices impact belowground associated diversity as research related to this issue is scarce. This study aims to investigate the effects of different fire prevention treatments and site history on bacterial and fungi co-response and co-occurrence patterns over a fire-risky scrubland ecosystem. Two different site histories were studied by applying three different fire prevention treatments and samples were analyzed by amplification and sequencing of ITS2 and 16S rDNA for fungi and bacteria, respectively. The data revealed that site history, especially regarding fire occurrence, strongly influenced the microbial community. Young burnt areas tended to have a more homogeneous and lower microbial diversity, suggesting environmental filtering to a heat-resistant community. In comparison, young clearing history also showed a significant impact on the fungal community but not on the bacteria. Some bacteria genera were efficient predictors of fungal diversity and richness. For instance, Ktedonobacter and Desertibacter were a predictor of the presence of the edible mycorrhizal bolete Boletus edulis. These results demonstrate fungal and bacterial community co-response to fire prevention treatments and provide new tools for forecasting forest management impacts on microbial communities.
Urbanization directly and indirectly impacts biodiversity to the extent that it is considered one of the main causes of biotic homogenization and extinction. However, urban green areas can act as reservoir of biodiversity, and knowledge regarding species distribution in such contexts is crucial to define appropriate conservation and management strategies. Since inventories of species are generally time-consuming and costly, a commonly used approach consists in the use of surrogate species. However, studies investigating the effectiveness of surrogate species in urban environments still seem to be under-represented. In this research, we investigated the biodiversity of ants, plants, and carabid beetles in six different green areas within the urban area of the city of Trieste. The role of vascular plants as a potential surrogate for the diversity of ants and carabid beetles has been tested, investigating the influence of the environmental variables (dead wood, litter, anthropic disturbance, bare soil, bedrocks and rocks) on these relationships. Patterns of species richness and complementarity were compared among the sampled sites and their correlations were tested with Mantel tests and Co-Correspondence Analysis (Co-CA). Results pointed out that even disturbed and isolated sites within the urbanised matrix can host a high diversity of species of ants, carabids and plants, while in the semi-natural sites intermediate diversity levels were found. Plants were found to correlate directly with the diversity of ants; on the contrary, carabid species composition resulted only indirectly influenced by vascular plants, confirming the key role of abiotic variables in determining carabid diversity. CoCA showed a clear distinction between forested and semi-natural environments and more open and disturbed environments. Furthermore, the CoCA highlighted that the considered environmental variables (particularly dead wood, anthropic disturbance, rocks and litter) can significantly influence the distribution of analysed taxa. Our results highlight the important role of urban green areas within the urban matrix as source of biodiversity and, furthermore, once more, support the role of vascular plants as meaningful surrogate for the diversity of ants and carabids.
Soil invertebrates represent almost a quarter of the total diversity of living organisms and their activity affects the entire soil ecological process. The choice of adequate thinning systems may differently affect soil nematode and microarthropod biodiversity in artificial black pinewoods. In this work, the results of the impact of different thinnings on the structure of nematode and microarthropod communities was reported. In a short-term experiment, thinning from below and selective thinning were compared to unmanaged stands to provide indications at the regional scale in central Italy. Soil nematode and microarthropod biodiversity was explored by examining community structure, assessing biodiversity. The interaction between environmental variables (crown volume, Photosynthetically Active Radiation, soil texture, soil temperature, and moisture) with taxa abundance of nematodes and microarthropods were also reported. The results indicated that the effects of thinning practices were temporary and varied between years. Soil nematode community shifted during the first and third years of thinning managements only in the Pratomagno site, while soil microarthropod community shifted in both sites only in the second year. The total nematode abundance was minimally affected by thinning practices, while the nematode community composition showed a decrease of omnivores and predators in the first years. Soil indicators showed inconsistent results. In microarthropods, mites and collembola were the least affected by thinning in terms of abundance and species biodiversity, while eu-edaphic taxa of Chilopoda, Diplopoda, and Pauropoda were not influenced by thinning, hemi-edaphic and epi-edaphic taxa of Coleoptera, Diptera, Hymenoptera, Tysanoptera, and Hemiptera were negatively affected. Soil indicators such as Shannon-Weiner and Simpson indices and soil biological quality (QBS-ar) improved in thinning from below in both sites. Soil temperature and moisture were the main driving factors in affecting soil nematode and microarthropods communities. Thinning from below probably allowed a more rapid recovery than selective thinning.
Extensive areas of native vegetation have been cleared to establish commercial exotic tree plantations in south-central Chile, a region known as a world biodiversity hotspot. Despite increasing societal demands to restore native forests in parts of the landscape, documented experiences for this form of restoration are lacking. We conducted a landscape-replicated experiment to test the influence of different harvesting treatments (clearcut, strip-cutting and unharvested control) on the early establishment of native tree species in 20-year-old Pinus radiata plantations. Group plantings of shade-intolerant (Nothofagus dombeyi; Nothofagus obliqua), semi-tolerant (Nothofagus alpina; Laurelia sempervirens) and shade–tolerant species (Aextoxicon punctatum; Cryptocarya alba) were established across the treatments, and seedling performance and water status were monitored during the first two growing seasons. Mean survival was significantly higher in the strip-cuttings (77%) and control (70%) than in the clearcuts (38%), while mean height and root collar diameter growth were significantly higher in the strip-cuttings (16 cm year-1; 0.2 cm year-1) and clearcuts (16 cm year-1; 0.2 cm year-1) than in the control (5 cm year-1; 0.1 cm year-1). Shade-intolerant and semi-tolerant species showed the highest growth responses to openings. Leaf water potential was significantly higher in seedlings in the strip-cuttings than those in the control and clearcuts, and stomatal conductance was significantly higher in the strip-cuttings and clearcuts than in the control. Higher seedling performances and lower water stress in the strip-cutting treatment suggest that partial canopy removal is a suitable method for artificial regeneration of native tree species with different shade tolerances for native forest restoration from P. radiata plantations.
Plantations are playing an increasingly important role in providing forest products and improving the ecological environment, but they also face many challenges, such as low biodiversity, severe pest and disease problems, reduced productivity, and diminished soil fertility. Reasonable management strategies are vital for their sustainability. In this study, we took a Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantation as an example to demonstrate the effects of thinning and mixing on the species diversity and structural diversity of plantations at the stand level over a rotation period (1993-2018). An intermediate thinning (26% of plant abundance) was conducted in a Chinese fir pure plantation in mid-age (2008), and a mixed forest stand of Chinese fir and Michelia macclurei Dandy was established directly. Thinning and mixing greatly increased the species diversity at the stand level, enhanced the mixture, transformed the pattern from regular to random distribution , and made the size differentiation of trees random. Thinning and mixing also greatly improved the mixture and dominance of Chinese fir. M. macclurei had an obvious advantage in tree size and maintained a high mixture proportion. Moreover, the diameter classes of the stands were bimodal. Chinese fir and M. macclurei showed a unimodal distribution of diameter, but other later-coming species with a larger number of individuals displayed a typical reverse J-shaped distribution. Our results suggest that both thinning and mixed planting may promote species diversity and structure over a long timescale, but thinning achieves these characteristics earlier because thinning directly manipulates structure in a way that accelerates stand development.
Stem tapers are mathematical functions modelling the relative decrease of diameter (rD) as the relative height (rH) increase in trees and can be successfully used in precision forest harvesting. In this paper, the diameters of the stem at various height of 202 Pinus nigra trees were fully measured by means of an optical relascope (CRITERION RD 1000) by adopting a two-steps non-destructive strategy. Data were modelled with four equations including a linear model, two polynomial functions (second and third order) and the Generalised Additive Model. Predictions were also compared with the output from the TapeR R package, an object-oriented tool implementing the β-Spline functions and widely used in the literature and scientific research. Overall, the high quality of the database was detected as the most important driver for modelling with algorithms almost equivalent each other. The use of a non-destructive sampling method allowed the full measurement of all the trees necessary to build a mathematical function properly. The results clearly highlight the ability of all the tested models to reach a high statistical significance with an adjusted-R squared higher than 0.9. A very low mean relative absolute error was also calculated with a cross validation procedure and small standard deviation were associated. Substantial differences were detected with the TapeR prediction. Indeed, the use of mixed models improved the data handling with outputs not affected by autocorrelation which is one of the main issues when measuring trees profile. The profile data violate one of the basic assumptions of modelling: the independence of sampled units (i.e., autocorrelation of measured values across the stem of a tree). Consequently, the use of simple parametric equations can only be a temporary resource before more complex built-in apps are able to allow basic users to exploit more powerful modelling techniques.
European black pine (Pinus nigra J.F.Arnold) is an ecologically and economically important conifer growing across southern Europe and the Mediterranean Basin in a variety of habitats. Its morphological and ecological variabilities as well as geographic origin are the basis for subspecies level taxonomic identification and forestry practice recommendations. Yet, no true consensus exists and genomic resources are lacking for resolving the taxonomy of P. nigra and assessing its adaptive potential. To provide genetic tools for further research, we generated novel genomic resources using six de novo transcriptomic assemblies representing major biogeographic regions where the species is growing naturally. Using two closely related species, Pinus sylvestris and Pinus halepensis, as outgroups, we identified a set of 2200 nuclear, putatively orthologous, single-copy genes. In addition, we identified a set of 405,624 polymorphic SNPs for P. nigra. Based on these resources, we were able to confirm the division of P. nigra into two wide geographical population groups and to provide new insights into evolutionary dynamics of the species.
Since the mid-19th century, Pinus nigra plantations have played a key role in the restoration of degraded European landscapes. Nowadays, these plantations are aging and prone to natural disturbances, insect infestations, and diseases. For their successful gradual conversion, knowledge of optimal gap spatiotemporal dynamics is crucial. We studied herb and natural regeneration patterns along with site factors on 477 subplots within 44 plots distributed over four stand types: closed stand (14% diffuse light), open stand (21%), gap edge (23%), and gap (57%). Despite the abundant Quercus petraea, Q. cerris, and Q. pubescens mast year, no one-year seedlings were recorded, which is likely due to the summer drought. Short seedlings (h < 20 cm) of Quercus sp., Fraxinus ornus and Ostrya carpinifolia were more successful within closed stands. Short Quercus seedlings were positively associated with soil depth and negatively associated with soil nutrients, distance to seed trees, and Sesleria autumnalis coverage. Taller Quercus seedlings required more light than both of its strongest competitors and were positively related to humid soils and less rocky sites. Ungulate overbrowsing significantly impeded natural regeneration. The results indicate a satisfactory Quercus density for conversion and the importance of advanced regeneration, which should be gradually, but persistently, released by progressively widening gaps.
Soil microbial communities are an important part of ecosystems that possess the capability to improve ecosystem services; however, several aspects of the ecology of forest soil bacterial communities are still unknown. Here, we investigated the impact of land-use change on soil bacterial communities and the soil characteristics. High-throughput sequencing was used to ascertain the bacterial diversity and canonical correspondence analysis was used to determine relationships between the bacterial communities and environmental variables. Our results show spatial heterogeneity in the distribution of the microbial communities and significant relationships between the microbes and soil characteristics (axis 1 of the canonical correspondence analysis (CCA) plot explained 64.55% of the total variance while axis 2 described 24.49%). Knowledge of this is essential as it has direct consequences for the functioning of the soil ecosystem.
The soil microbiome governs biogeochemical cycling of macronutrients, micronutrients and other elements vital for the growth of plants and animal life. Understanding and predicting the impact of climate change on soil microbiomes and the ecosystem services they provide present a grand challenge and major opportunity as we direct our research efforts towards one of the most pressing problems facing our planet. In this Review, we explore the current state of knowledge about the impacts of climate change on soil microorganisms in different climate-sensitive soil ecosystems, as well as potential ways that soil microorganisms can be harnessed to help mitigate the negative consequences of climate change.
We tested the ecosystem functions of microbial diversity with a focus on ammonification (involving diverse microbial taxa) and nitrification (involving only specialized microbial taxa) in forest nitrogen cycling. This study was conducted on a forest slope, in which the soil environment and plant growth gradually changed. We measured the gross and net rates of ammonification and nitrification, the abundance of predicted ammonifiers and nitrifiers, and their community compositions in the soils. The abundance of predicted ammonifiers did not change along the soil environmental gradient, leading to no significant change in the gross ammonification rate. On the other hand, the abundance of nitrifiers and the gross nitrification rate gradually changed. These accordingly determined the spatial distribution of net accumulation of ammonium and nitrate available to plants. The community composition of predicted ammonifiers gradually changed along the slope, implying that diverse ammonifiers were more likely to include taxa that were acclimated to the soil environment and performed ammonification at different slope locations than specialized nitrifiers. Our findings suggest that the abundance of ammonifiers and nitrifiers directly affects the corresponding nitrogen transformation rates, and that their diversity affects the stability of the rates against environmental changes. This study highlights the role of microbial diversity in biogeochemical processes under changing environments and plant growth.
The cover of introduced tree species in Europe has recently increased, due to several factors. Attempts to understand the impact of non-native edificator trees on the environmental conditions and diversity of undergrowth have so far been limited to a few studies. In this paper, we analyse the effect of one of the most commonly planted non-native tree species–black pine (Pinus nigra J. F. Arnold) in the Carpathian-Pannonian region, north of the border of its native occurrence. The objectives of our study were to determine the following: (i) How does black pine, as a non-native edificator, change the forest structure and environmental conditions in comparison to those of native communities? (ii) How does black pine change the species composition of undergrowth in comparison to that of native communities? (iii) Which factors are associated with the impact of black pine on diversity? To answer these questions, we used the twin plot method, sampling two neighbouring plots with the same environmental conditions in which one plot of the pair is in a forest with native tree species composition and the second plot is in a planted non-native Pinus nigra plantation. We found that in forests dominated by the non-native black pine, (a) the tree canopy is significantly more open; (b) the cover of the shrub layer is significantly higher; (c) the needles of black pine form a significantly thicker litter layer and (d) the cover of the herb layer is significantly lower than that in the native forest. (e) Black pine plays a vital role in modifying local climate by altering air temperature and humidity; (f) there were no significant differences in the soil pH between black pine plantations and native forests; (g) the plantations of black pine cause changes in diversity at both the species and the community level and (h) the dissimilarity between black pine plantations and neighbouring native forests decreases at higher altitudes.
Deadwood is a substantial component of forests playing a central role in many ecosystem processes. It provides habitats for a multitude of wood-dependent organisms, maintaining the ecosystem health and reducing the effect of natural disturbances. Deadwood is recognized as an indicator of local species diversity and contributes to the global carbon pools and nutrient cycles. Despite its importance, how saproxylic communities respond to deadwood dynamics across multiple spatial and temporal scales is still not clear. With the present review, we aim to summarize the effects of deadwood characteristics on the diversity and composition of saproxylic insects and fungi, with focus on Euro-pean forests. We also discuss the influence of other biotic and abiotic components that indirectly affect these communities by altering wood continuity and variety. Niche differentiation is the main ecological driver of saproxylic organisms , as the presence of multiple microhabitats supports differently specialized taxa. The assemblage and richness of these saproxylic communities within forest ecosystems can be considered as indicators of climate-smart forestry trajectories. This aspect deserves to be regarded as a major target in sustainable forest management plans, especially in mountain areas, where the conservation of threatened species and the promotion of biodiverse forests are considered a priority.
Predicted changes in global climate might negatively affect the soil microbiome and associated ecosystem processes in Mediterranean forests. Forest treatments, such as forest thinning, have been suggested to mitigate climate change impacts on vegetation by reducing competition between trees, thus increasing water availability. Studies addressing the combined effects of climate and forest thinning on belowground fungal communities are still scarce, being fundamental to elaborate adaptive strategies to global warming.
The aim of this study was to evaluate the tree density reduction effects on soil fungal communities and their response to inter-annual changes in weather conditions. The temporal dynamics of soil fungal communities in relation to these two drivers (i.e., forest management and weather conditions) were studied from 2009 until 2014 in a set of 12 pairs of thinned and un-thinned plots dominated by Pinus pinaster Ait. Thinning (from 30% up to 70% reduction in stand basal area) was conducted in 2009 and soil fungal community composition was studied during 4 years. Here, we used autumn precipitation and temperature to describe the impact of inter-annual weather changes. We used Pacific Biosciences sequencing of fungal ITS2 amplicons to study fungal communities in soil samples. Forest thinning did not significantly affect fungal community composition nor fungal species richness and diversity, indicating that the soil fungal community is resistant to forest thinning regardless of its intensity. However, fungal species composition changed progressively across years, both at the species level and with regards to functional guilds. These changes in community composition were partly driven by inter-annual variation in precipitation and temperature, with free-living fungi increasing in abundance under wetter conditions, and symbiotic fungi being more prominent under drier and colder conditions. The results indicate that mycorrhizal communities in Mediterranean forest ecosystems can resist forest thinning, if enough trees and functional roots from thinned trees are retained.
Statistiche inventariali sugli attributi quantitativi, derivate dal rilevamento di terza fase del progetto INFC2005.
Provision of forest ecosystem services is influenced by site and stand characteristics as well as forest management practices. In order to evaluate the influence of forest management on ecosystem services provision, two artificial black pine forests located in Central Italy were studied where two different thinning approaches (traditional and selective) were applied under the SelPiBio LIFE project. Four main ecosystem services were selected and assessed: timber and bioenergy production, carbon sequestration, forest stand stability-protection, and biodiversity conservation. Even if not supported by statistical evidence, results highlighted an interesting trend just 2 years after treatment. The selective thinning was able to enhance the majority of ecosystem services compared to the traditional one. A higher growth rate of selected crop trees was measured (i.e., carbon sequestration). The slenderness ratio was sensibly reduced (i.e., mechanical stability) with a positive implication on soil retention and the prevention of landslides. Moreover, valuable and interesting commercial assortments have been proven to be retrieved from the stands with the selective approach. Larger and also better formed trees were harvested, given the impact of selective thinning on the co-dominant class. The Shannon index increased only with the selective thinning intervention. In conclusion, the provided results and methods are encouraging and might represent the basis for novel and longer monitoring efforts.
Aim of the study: Thinning experiments in Scots pine (Pinus sylvestris L.) stands have been carried out for many years in different regions of its distribution. The aim of this paper is to gather knowledge regarding the effects of thinning on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the context of climate change.Area of study: The review covers studies from different regions of the distribution area of Scots pineMaterial and methods: We reviewed the effect of thinning on four aspects: growth and yield, stability against snow and wind, response to drought, and ecosystem services.Main results: Heavy thinning involves a loss in volume yield, although the magnitude depends on the region, site and stand age. Thinning generally does not affect dominant height while the positive effect on tree diameter depends on the thinning regime. The stability of the stand against snow and wind is lower after the first thinning and increases in the long term. The impact of extreme droughts on tree growth is lower in thinned stands, which is linked to a better capacity to recover after the drought. Thinning generally reduces the wood quality, litter mass, and stand structural diversity, while having neutral or positive effects on other ecosystem services, although these effects can vary depending on the thinning regime. However, scarce information is available for most of the ecosystem services.Research highlight: Existing thinning experiments in Scots pine stands provided valuable information about thinning effects, but new experiments which cover a broad range of ecosystem services under different site conditions are still needed.
Context
The main aim of the SelPiBio LIFE project (www.selpibio.eu) is to demonstrate the effects of two thinning regimes, selective and from below, on soil biodiversity in young black pine stands. The spatial structure of forests and the relationships between trees are a good proxy of overall biodiversity level. Spatial datasets with geo referenced trees and related mensurational data represent the highest level of information for forest inventories and research activities.
Aims
This dataset has been developed during the A2 Action (Assessment of structural and mensurational parameters of the forest stands and the dead wood) of the project, to record the main mensurational parameters of the studied black pine stands. A tree-level database was compiled to describe the vertical and horizontal structure of 54 monitoring plots before the application of the silvicultural treatment.
Methods
In addition to classical in-field measurements (e.g. diameters at breast height, total height of the tree, crown depth etc.), all trees were georeferenced by means of polar coordinates collected from the centre of each monitoring plot, including crown projection on the ground, described with eight points. Then, a polynomial spline function was fitted across the recorded data to obtain a convex polygon and to calculate crown area and crown perimeter of each measured tree in GIS environment.
Results
A polygonal ESRI shapefile in ETRS89/UTM32N reference system (EPSG: 25832) with 4171 records representing the crown projections on the ground of each measured tree with all the mensurational parameters included into the attribute table. The database is freely available under the Creative Commons Attribution-NonCommercial 4. 182 0 License.
Conclusion
With this database, a wide range of forestry-related indices could be easily calculated, including geostatistical analysis and autocorrelation functions, to compare Italian artificial black pine stands with other studied forests.
In young black pine plantations, the most valuable and interesting thinning scheme is mainly based on the positive selection of dominant and well-shaped trees to be candidates for carbon sequestration, timber production and natural regeneration. The mechanical stability of candidate trees is here a fundamental skill that must be taken into account and the slenderness ratio (HD) is one of the main indicators. HD has been recently proved to be correlated to the living whorl number (LWN) by Cantiani & Chiavetta (2015). In this study, the statistical model was re-calibrated in order to study the influence of soil fertility on the HD - Living whorls number (LWN) relationship.
The fertility-balanced models estimated a different LWN threshold. The model for the highest fertility class (Site index 24) estimated 12 LWN (RMSE of 20%). Similarly, a lower value were detected for the other two fertility classes, SI20 and SI16, where 10 LWN were considered enough with an associated RMSE of 16% and 17% respectively. Compared to the general model provided by Cantiani & Chiavetta (11 LWN with 18% of RMSE) the site index approach improved the accuracy and reliability.
The cork oak forest is an ecosystem playing a major role in Moroccan socio-economy and biodiversity conservation. However, this ecosystem is negatively impacted by extensive human- and climate-driven pressures, causing a strong decrease in its distribution and a worsening of the desertification processes. This study aims at characterising the impact of cork oak forest management on a major actor of its functioning, the ectomycorrhizal (EcM) fungal community associated with Quercus suber, and the determination of EcM bio-indicators. The EcM fungal community has been monitored during spring and winter seasons in two sites of the Moroccan Mâamora forest, corresponding to a forest site either impacted by human activities or protected. A significant impact of cork oak forest management on the EcM fungal community has been revealed, with major differences during the summer season. The results confirmed the potential ecological significance of several EcM fungi (e.g., Cenococcum) in the sustainability of the cork oak forest functioning, but also the significant association of certain EcM fungi (Pachyphloeus, Russula, Tomentella) with a perturbation or a season, and consequently to the cork oak forest status or to climatic conditions, respectively. The development of study at the Mediterranean scale may improve the robustness of ecological models to predict the impact of global changes on this emblematic ecosystem of Mediterranean basin.
Copyright © 2017 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
PurposeThe bacterial phylum Verrucomicrobia plays important roles in biogeochemical cycling processes, while the ecology of this phylum is still unclear. Previous elevational studies mainly focused on whole bacterial communities, while no study exclusively picked out Verrucomicrobia. Our objectives were to investigate the abundance, diversity and community composition of soil Verrucomicrobia across an elevation gradient on Changbai Mountain. Materials and methodsIn total, 24 soil samples representing six elevation gradients were collected. Primer set 515F/806R was used for PCR amplifications and sequencing was conducted on an Illumina HiSeq2000 platform. Data sets comprising of Verrucomicrobial phylum were culled from all quality sequences for the further analyses of Verrucomicrobial diversity and community composition. Results and discussionThe relative abundance of Verrucomicrobia accounted for ~20% of the total bacterial communities, and Spartobacteria and DA101 were the most dominant class and genus, respectively. Verrucomicrobia community composition differed significantly among elevations, while the Verrucomicrobia diversity showed no apparent trend along elevation although the richness of some classes or genera significantly changed with elevation. The Verrucomicrobial community composition, diversity, and relative abundance of specific classes or genera were significantly correlated with soil pH and carbon/nitrogen ratio (C:N ratio). Conclusions
These results indicated that Verrucomicrobia were abundant in Changbai Mountain soils, and Verrucomicrobial elevational distribution was strongly influenced by soil pH and C:N ratio. Our results also provide potential evidence that the dominant genus DA101 occupies different ecological niches and performs oligotrophic life history strategy in soil environment.
In Mediterranean regions, climate change increasingly affect tree species distributions. Conifer forests under continuing disturbance show a more rapid shift to dominance by beech and other temperate broadleaves. Thus, there is an urgent need to conserve coniferous vegetation to avoid local extinction. Gap opening has profound effects on the structure and dynamics of most forests and may represent a sustainable way to restore coniferous ecosystems in Mediterranean habitats. What kind of artificial canopy opening is the most sustainable and effective means for restoring coniferous ecosystem functions? We explored the efficacy of artificial gaps in regeneration and dynamics of coniferous in Mediterranean environment. We examined how regeneration of different tree species is associated with soil environmental conditions and how gaps of different sizes influence the ecology and management of Mediterranean forest. Specifically, we analyzed gap disturbance in silver fir and black pine stands, as they dominate central and southern Italian forests. We demonstrated a specificity between gap size and coniferous species regeneration, indicating that small gaps (about 200 m2) favor silver fir regeneration, while black pine, depending on its subspecies, regenerates both in small and medium gaps (about 500 m2). Further, we found that gap characteristics (age and shape) and suitable substrate availability are the primary factors affecting seedling establishment. Our results provide functional information to design a silvicultural system useful to manage the natural regeneration of Mediterranean forest minimizing the environmental and visual impact.
A conversion of previously even-aged pine-dominated forests to uneven-aged and multi-functional oak-dominated forests has been ongoing since 1993 in the Pyramida experimental forest (95 ha) situated in the buffer zone of Podyjí National Park, Czech Republic. Based on repeated surveys in 1992, 2003 and 2013, the conversion was assessed according to changes in: (i) the proportion of species; (ii) the distribution of DBH; (iii) the distribution of patches; and (iv) the distribution of forest types. The proportion of conifers decreased from 61.0% to 42.0%, and the proportion of broadleaved species increased accordingly. A sharp decline in the number of trees in the DBH class 70-109 mm was caused by the intense release of understorey broadleaved trees in young Scots pine small pole stage stands. The number of large habitat trees steadily increased in the DBH classes 430+ mm. The mean size of one patch decreased from 0.8 ha (1992) to 0.4 ha (2013). The spatial proportion of the target forest type (uneven-aged oak-dominated forest) increased from 8.5% in 1992 to 45.0% in 2013, and 35.1% of the area was fully converted during the 20 years. We expect 69.1% of the area to be converted after 30 years (2023).
Una pubblicazione che descrive obiettivi e tecnica del trattamento selvicolturale proposto per le pinete artificiali di pino nero dell’Appennino. Si tratta di un diradamento di tipo selettivo finalizzato ad accrescere: la stabilità meccanica complessiva (funzione protettiva), la capacità di crescita delle piante (funzione produttiva), la differenziazione strutturale (funzione di aumento di biodiversità). Il manuale descrive le tecniche adottate che prevedono la scelta di piante candidate ed il taglio delle dirette concorrenti sul piano dominante. L’obiettivo è quello di aprire la copertura dando più spazio alle chiome per incrementarne sviluppo e la capacità fotosintetica e, contemporaneamente, determinare al suolo un diverso regime di luce, acqua e temperatura con conseguente aumento della biodiversità vegetale del sottobosco, quella livello dell’ambiente suolo (funghi, batteri, flora, mesofauna, nematodi) nonché la funzionalità complessiva dell’ecosistema.
Il protocollo sperimentale prevede il confronto del diradamento selettivo con quello tradizionale e con il non intervento attraverso rilievi ante e post interventi specifici per l’analisi della biodiversità delle componenti di sottobosco e suolo di cui il manuale riporta le metodologie adottate. La trattazione si conclude con la descrizione delle due aree oggetto del progetto: prato magno e monte Amiata e riporta caratteristiche e primi risultati relativi agli interventi di diradamento applicati.
Application of bioorganic fertilizers has been reported to improve crop yields and change soil bacterial community structure; however, little work has been done in apple orchard soils where the biological properties of the soils are being degraded due to long-term application of chemical fertilizers. In this study, we used Illumina-based sequencing approach to characterize the bacterial community in the 0–60-cm soil profile under different fertilizer regimes in the Loess Plateau. The experiment includes three treatments: (1) control without fertilization (CK); (2) application of chemical fertilizer (CF); and (3) application of bioorganic fertilizer and organic-inorganic mixed fertilizer (BOF). The results showed that the treatment BOF increased the apple yields by 114 and 67 % compared to the CK and CF treatments, respectively. The treatment BOF also increased the soil organic matter (SOM) by 22 and 16 % compared to the CK and CF treatments, respectively. The Illumina-based sequencing showed that Acidobacteria and Proteobacteria were the predominant phyla and Alphaproteobacteria and Gammaproteobacteria were the most abundant classes in the soil profile. The bacterial richness for ACE was increased after the addition of BOF. Compared to CK and CF treatments, BOF-treated soil revealed higher abundance of Proteobacteria, Alphaproteobacteria and Gammaproteobacteria, Rhizobiales, and Xanthomonadales while Acidobacteria, Gp7, Gp17, and Sphaerobacter were found in lower abundance throughout the soil profile. Bacterial community structure varied with soil depth under different fertilizer treatments, e.g., the bacterial richness, diversity, and the relative abundance of Verruccomicrobia, Candidatus Brocadiales, and Skermanella were decreased with the soil depth in all three treatments. Permutational multivariate analysis showed that the fertilizer regime was the major factor than soil depth in the variations of the bacterial community composition. Two groups, Lysobacter and Rhodospirillaceae, were found to be the significantly increased by the BOF addition and the genus Lysobacter may identify members of this group effective in biological control-based plant disease management and the members of family Rhodospirillaceae had an important role in fixing molecular nitrogen. These results strengthen the understanding of responses to the BOF and possible interactions within bacterial communities in soil that can be associated with disease suppression and the accumulation of carbon and nitrogen. The increase of apple yields after the application of BOF might be attributed to the fact that the application of BOF increased SOM, and soil total nitrogen, and changed the bacterial community by enriching Rhodospirillaceae, Alphaprotreobateria, and Proteobacteria.
Since adequate information on the distribution of biodiversity is hardly achievable, biodiversity indicators are necessary to support the management of ecosystems. These surrogates assume that either some habitat features, or the biodiversity patterns observed in a well-known taxon, can be used as a proxy of the diversity of one or more target taxa. Nevertheless, at least for certain taxa, the validity of this assumption has not yet been sufficiently demonstrated. We investigated the effectiveness of both a habitat- and a taxa-based surrogate in six European beech forests in the Apennines. Particularly, we tested: (1) whether the stand structural complexity and the herb-layer species richness were good predictors of the fine-scale patterns of species richness of five groups of forest-dwelling organisms (beetles, saproxylic and epigeous fungi, birds and epiphytic lichens); and (2) the cross-taxon congruence in species complementarity and composition between herb-layer plants and the target taxa. We used Generalized Linear Mixed Models (GLMMs), accumulation curves and Procrustes analysis to evaluate the effectiveness of these surrogates when species richness, complementarity and composition were considered, respectively. Our results provided a limited support to the hypothesis that the herb-layer plants and the stand structural complexity were good surrogates of the target taxa. Although the richness of the herb-layer plants received a stronger support from the data than structural complexity as a predictor for the general patterns of species richness, the overall magnitude of this effect was weak and distinct taxa responded differently. For instance, for increasing levels of herb-layer richness, the richness of lichens showed a marked increase, while the richness of saproxylic fungi decreased. We also found significantly similar complementarity patterns between the herb-layer plants and beetles, as well as a significant congruence in species composition between herb-layer plants and saproxylic fungi. Finally, when different stand structural attributes were considered singularly, only the total amount of deadwood received support from the data as a predictor of the overall species richness. At the fine scale of this study, herb-layer plants and stand structural complexity did not prove to be effective surrogates of multi-taxon biodiversity in well-preserved southern European beech forests. Rather than on weak surrogates, these results suggest that sound conservation decisions should be supported by the information provided by comprehensive multi-taxonomic assessments of forest biodiversity.
Pinus nigra J.F. Arnold, known as European black pine or black pine, is a fast-growing conifer with a wide but fragmented distribution across Europe and Asia Minor, predominantly in mountain areas. It has also become naturalised in some areas in North America. It is subdivided into several distinct subspecies and its taxonomic status is still a subject of debate among specialists. Black pine regenerates with difficulties after a fire event, particularly during periods with extreme droughts when the development of seedlings can become challenging. This is thought to trigger a reduction of its habitat in southern Europe; on the contrary in Central Europe the climate amelioration might generate an expansion.
Macrofungi constitute a group of the high-value forest resources worldwide. In this paper, we report species richness and composition of the macrofungi in sal (Shorea robusta) forests of mid-hill central Nepal, which were managed for 4–29 years by the local communities. The sal forests were rich in macrofungi (115 species) with Polyporaceae being the largest family followed by Clavariaceae. Saprotrophic fungi were more common than mycorrhizal species. The proportion of mycorrhiza was <40% of the total macrofungi species which might have indicated the deteriorated condition of the forests before the initiation of conservation management. However, the proportion of mycorrhizal species was slightly higher in the forests managed for >10 years than in the forests managed for short period. The species richness increased with increasing canopy and litter cover. Since silvicultural activities and resource utilization often have negative impacts to macrofungal diversity, these activities need to be optimized to keep balance between forest management and biodiversity conservation.
Tree crown size determines among others tree's growth, carbon sequestration, shading, filtering of fine air particulates, and risk of wind-breaking. The dependence of crown size on species, resource supply, and tree age complicates an accurate evaluation of a tree's space requirement, and its size-dependent functions and services in urban as well as in forested areas. Based on a world-wide dataset of tree crown measurements of 22 common urban tree species we first derived species-specific crown radius-stem diameter relationships for open grown conditions. By cluster analysis we then assigned the 22 species to 5 crown extension types and developed mean relationships of tree height, crown radius, crown projection area, and crown volume depending on tree diameter for each type. This allometric analysis yielded auxiliary relationships which can be used for estimating the species-specific crown size and dynamics at a given tree dimension. We discuss how the results can support the choice and initial spacing of particular species and the assessment and prognosis of their functions and services.
Black pine has been used often in central and southern Italy to reforest mountainous areas depleted by the intensive use of natural resources. The main purpose of establishing pine forests in Italy was to protect the soil from excessive erosion, and also to facilitate the natural succession toward mixed forests with deciduous species. The most common silvicultural treatments in Europe currently aim at maximizing the stability of the stands and facilitating the transition from pure to mixed stands comprising a larger component of native tree species. In this work, we investigated the relationships between the living whorls number and four indexes of individual tree stability: the slenderness ratio, the crown depth, the crown projection, and an eccentricity index of the canopy. The data set used was composed of 1098 trees from ten black pine plantations located in central Italy. Our results demonstrate that the living whorls number can be handily used to predict the slenderness ratio with an error of 18%. A non-parametric model based on a reduced number of field measures
was obtained as a support for thinning operations aimed at improving single tree stability.
Forest thinning is an important method for managing forests, changing forest structure, biological diversity and community. This study examined forest thinning effects on macrofungal diversity and the environmental factors affecting fruiting and community structure. Field surveys were conducted from 2006 to 2010 in 35-year-old Cryptomeria japonica plantations in central Taiwan. Thinning was completed in October 2007 and included control, 25% thinning, and 50% thinning treatments. Each treatment had four replications. Forest thinning and time affected macrofungal species richness observed but not abundance. Thinning influenced macrofungal community compositions; however, the difference between the two thinning intensities was not significant. The macrofungal community showed significant differences between communities of eastern and northern aspect. A redundancy analysis indicated that macrofungal communities in the C. japonica plantations were significantly affected by relative humidity, light, canopy cover, soil water content, soil temperature, soil pH value and soil texture. The fruiting of a dominant coral fungal species, Scytinopogon sp., was affected by thinning and light. The fruiting bodies of this species decreased in the 25% thinning plots and disappeared in 50% thinning plots in the first two years post-thinning, but were recorded in the third year post-thinning. After thinning, macrofungal species richness observed decreased, the community changed, and changes were associated with environmental conditions. Forest thinning decreased observable macrofungal diversity and changed the community structure, and these changes were associated with environmental variation after thinning.
Accettato il 29 settembre 2010 Riassunto – Si riportano i risultati di una sperimentazione impostata nel 1978 sul trattamento selvicolturale di una pineta di impianto di pino nero nel territorio del Pratomagno casentinese (Arezzo). Le tesi poste a confronto sono state: (i) diradamento dal basso moderato; (ii) diradamento dal basso forte; (iii) controllo. Il trattamento ha previsto tre diradamenti nel 1978, nel 1999 e nel 2009 alle età di 24, 45 e 55 anni. Si analizzano gli interventi attuati e gli effetti nel tempo sui parametri dendrometrici e di stabilità del soprassuolo H/D (rapporto ipsodiametrico medio) e H/D dom (rapporto ipsodiametrico dominante). Sono analizzati poi i parametri: rapporto ipsodiametrico, profondità, area di insidenza ed eccentricità della chioma su un campione di alberi stratificati per classe sociale e per tesi di trattamento in confronto con uno cresciuto in assenza di concorrenza. I risultati confermano che i diradamenti sono il mezzo più incisivo per accrescere la stabilità di popolamenti forestali artificiali monoplani. Tipo, regime e grado dei singoli interventi in rapporto allo stadio di sviluppo sono gli elementi determinanti. Nei diradamenti dal basso l'intensità dell' intervento influisce direttamente sull'incremento dei parametri di stabilità nel tempo soltanto se gli interventi interessano anche il piano dominante. La sperimentazione ha dimostrato che tutti i parametri di stabilità sono migliorati nei dieci anni successivi al diradamento intermedio eseguito a 45 anni, in misura maggiore nella tesi di diradamento forte. Abstract – Effects of silvicultural treatment on the stability of black pine plantations. Black pine plantations have been established at the purpose of recovering a forest cover to marginal soils, mostly throughout the Apennines range in Italy, since the end of the eighteenth century and up to the mid 1900. Both the decay of forest cover and soil erosion were the outcome of the long-lasting overuse through the intensive forest exploitation practices, grazing of the forest floor and wildfires, occurring since many centuries ago. The primary function of pine reafforestation was therefore to re-establish a first cover with a pioneer species, preparatory to future mixed forest types based on the natural reintroduction of broadleaves originally living in the same areas, mainly deciduous oaks and beech in the upper part. These goals have been partly met over the wide reafforestation area; the key functions of pine stands are today the protection against soil erosion and the hydrological regulation of catchments. The pine stands have been assuming today also a scenic role because they have been incorporated in the landscape physiognomy. A series of thinning up to the regeneration phase had been planned by foresters since the design of these plantations, but many stands have grown unthinned and fully stocked for a long time, this condition contributing a less mechanical stability of trees. Alternative forms of regeneration in grown-up stands have been and are being tested to improve both the natural and artificial establishment of indigenous species, but thinnings remain, even if a tardy measure, the main practice enforceable to these pine forests. The results of experimental trials undertaken in the black pine forest stand located in Pratomagno casentinese (Arezzo) are being reported in the paper. The study started in 1978 and the following theses were tested (A) heavy thinning from below; (B) moderate thinning from below; (C) control. Three thinnings were carried out in 1978, 1999 and 2009 at the ages of 24, 45 and 55. The action over time of each intervention on the mensurational and mechanical stability parameters (H/D ratio H/D dom ratio), are being analyzed. The stability parameters of the pine forest after three interventions (H/D ratio, crown ratio, horizontal crown projection and eccentricity of the crown) have been also analyzed on a sample of trees per thesis and compared with those of trees grown in absence of competition. Sampled trees were sorted per social class. Results proved that type, interval and intensity of thinning related to the age of intervention are the main determinants of a successful treatment. Thinnings from below increase individual stability over time only when also trees living in the main crop layer are being removed. The trials showed the improvement of stability parameters following the intermediate thinning applied at the age of 45. The thesis of heavy thinning had the best performance as for the awaited purpose.
A holy grail of conservation is to find simple but reliable measures of environmental change to guide management. For example, particular species or particular habitat attributes are often used as proxies for the abundance or diversity of a subset of other taxa. However, the efficacy of such kinds of species-based surrogates and habitat-based surrogates is rarely assessed, nor are different kinds of surrogates compared in terms of their relative effectiveness. We use 30-year datasets on arboreal marsupials and vegetation structure to quantify the effectiveness of: (1) the abundance of a particular species of arboreal marsupial as a species-based surrogate for other arboreal marsupial taxa, (2) hollow-bearing tree abundance as a habitat-based surrogate for arboreal marsupial abundance, and (3) a combination of species- and habitat-based surrogates. We also quantify the robustness of species-based and habitat-based surrogates over time. We then use the same approach to model overall species richness of arboreal marsupials. We show that a species-based surrogate can appear to be a valid surrogate until a habitat-based surrogate is co-examined, after which the effectiveness of the former is lost. The addition of a species-based surrogate to a habitat-based surrogate made little difference in explaining arboreal marsupial abundance, but altered the co-occurrence relationship between species. Hence, there was limited value in simultaneously using a combination of kinds of surrogates. The habitat-based surrogate also generally performed significantly better and was easier and less costly to gather than the species-based surrogate. We found that over 30 years of study, the relationships which underpinned the habitat-based surrogate generally remained positive but variable over time. Our work highlights why it is important to compare the effectiveness of different broad classes of surrogates and identify situations when either species- or habitat-based surrogates are likely to be superior.
Monocultural coniferous plantations have prevailed worldwide in recent decades, which supplied much of the world’s timber, but also exerted some negative effects on local ecologies and environmental systems. Continuous development has increased the various demands of human society for forests and it is necessary to balance concerns for the ecological and economic functions. Ample evidence indicates that mixed forests are an ideal option for providing more diversified ecological services and forest goods. Converting pure forests into mixed forests by introducing broad-leaved hardwood species below coniferous plantations has become an increasingly popular forest management strategy. Yet, there has been not enough research to date on suitable management methods for enhancing forest diversity and resilience in the context of forest conversion. To comprehensively examine how the intensity in Masson pine thinning influences forest evolution, seedlings of two native hardwood species were introduced below unthinned and thinned (varying intensity) Masson pine plantations. The effects of thinning on residual tree growth, seedling survival and growth, and understory vegetation development were analyzed using a generalized additive mixed model (GAMM). Monitoring results over 10 years indicate that thinning is a necessary management measure to accelerate forest succession in the conversion process; thinning exerts significant effects on the growth of residual trees, the survival and growth of seedlings, and the development of understory vegetation. Intense thinning results in more residual tree growth and enhances the richness and diversity of herbaceous species. However, excessive thinning can reduce the likelihood of seedling survival and growth as well as the richness and diversity of shrubs. Optimal thinning intensities appear to fall between 50% and 60% depending on the specific introduced species; light-demanding species may need higher overstory thinning intensity than shade-tolerant species. The biological characteristics of the introduced species must be taken into account to design an effective thinning strategy for pine plantations conversion.
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.
Soil plays a fundamental role in many ecological processes, throughout a complex network of above- and below-ground interactions. This has aroused increasing interest in the use of correlates for biodiversity assessment and has demonstrated their reliability with respect to proxies based on environmental data alone. Although co-variation of species richness and composition in forests has been discussed in the literature, only a few studies have explored these elements in forest plantations, which are generally thought to be poor in biodiversity, being aimed at timber production. Based on this premise our aims were 1) to test if cross-taxon congruence across different groups of organisms (bacteria, vascular plants, mushrooms, ectomycorrhizae, mycelium, carabids, microarthropods, nematodes) is consistent in artificial stands; 2) to evaluate the strength of relationships due to the existing environmental gradients as expressed by abiotic and biotic factors (soil, spatial-topographic, dendrometric variables). Correlations between groups were studied with Mantel and partial Mantel tests while variance partition analysis was applied to assess the relative effect of environmental variables on the robustness of observed relationships. Significant cross-taxon congruence was observed across almost all taxonomic groups pairs. However, only bacteria/mycelium and mushrooms/mycelium correlations remained significant after removing the environmental effect, suggesting that a strong abiotic influence drives species composition. Considering variation partitioning, the results highlighted the importance of bacteria as a potential indicator: bacteria were the taxonomic group with the highest compositional variance explained by the predictors used; furthermore, they proved to be involved in the only cases where the variance attributed solely to the pure effect of biotic or abiotic predictors was significant. Remarkably, the co-dependent effect of all predictors always explained the highest portion of total variation in all dependent taxa, testifying the intricate and dynamic interplay of environmental factors and biotic interactions in explaining cross-taxon congruence in forest plantations.
Monitoring restoration effectiveness implies that restoration measures should be evaluated using multiscale analysis and modelling approaches. In this way, the scale-dependent nature of ecosystem processes and dynamics can be adequately described. Here, we evaluated how grain size (i.e. the dimension of sampling units) and type of data (abundance vs. presence/absence) impact the analysis of the response to restoration management activities aiming at halting the loss of European beech forests with Abies alba in the central Apennines (Italy). The proposed analysis relies on forests sampled in three Sites of Community Importance (SCIs) located in central Italy. For each treatment (reference, control and impact), randomly located multi-scale plots were selected. Vascular plant occurrences were recorded twice in every plot during summer 2010 or 2011 (before restoration) and in 2013 or 2014 (after restoration). Analysis of species abundances, recorded at the largest grain size available (20 X 20 m plot), showed a significant change in plant species composition in restored sites just after two years from the restoration management. When presence/absence data were used previous results were less visible, for all the examined grains, in two out of the three sites, suggesting a site-dependent response.
The impacts of climate extremes on species, communities and ecosystems have become critical concerns to science and society. Under a changing climate, how restoration outcomes are affected by extreme climate variables is a largely unknown topic. We analyzed the effects of experimental factors (grazing and sowing of native species), extreme climate events (intense precipitation and extreme temperatures indexes) and their combination on the restoration progress of a dry, calcareous grassland in Tuscany (Italy) with a 1 year before/15 years continuous annual monitoring after, control/impact (BACI) experiment. Grazing had a beneficial effect on the diversity of the grassland, while sowing had a limited impact. The climatic index that most affected the entire plant community composition was the number of very heavy precipitation days. The interaction of grazing and extreme climatic indexes had a significant detrimental effect on restoration outcomes, increasing the cover of synanthropic and cosmopolitan-subcosmopolitan generalist species and decreasing the cover of more valuable species such endemic species. In the richer grazed plots, species richness showedn a lower sensitivity to the average precipitation per wet day.: this results suggest that dealing with climate extremes, the richest communities might not be the more resistant. In grazed site restoration outcomes can be negatively influenced by the intensification of precipitation and temperature extremes. In a context of progressive tropicalization of the Mediterranean area, to assist managers setting achievable restoration goals, restoration practitioners should consider that climate extremes might interfere with the beneficial effects of restoration practices.
Although bacteria within the Verrucomicrobia phylum are pervasive in soils around the world, they are under-represented in both isolate collections and genomic databases. Here, we describe a single verrucomicrobial group within the class Spartobacteria that is not closely related to any previously described taxa. We examined more than 1,000 soils and found this spartobacterial phylotype to be ubiquitous and consistently one of the most abundant soil bacterial phylotypes, particularly in grasslands, where it was typically the most abundant. We reconstructed a nearly complete genome of this phylotype from a soil metagenome for which we propose the provisional name 'Candidatus Udaeobacter copiosus'. The Ca. U. copiosus genome is unusually small for a cosmopolitan soil bacterium, estimated by one measure to be only 2.81 Mbp, compared to the predicted effective mean genome size of 4.74 Mbp for soil bacteria. Metabolic reconstruction suggests that Ca. U. copiosus is an aerobic heterotroph with numerous putative amino acid and vitamin auxotrophies. The large population size, relatively small genome and multiple putative auxotrophies characteristic of Ca. U. copiosus suggest that it may be undergoing streamlining selection to minimize cellular architecture, a phenomenon previously thought to be restricted to aquatic bacteria. Although many soil bacteria need relatively large, complex genomes to be successful in soil, Ca. U. copiosus appears to use an alternative strategy, sacrificing metabolic versatility for efficiency to become dominant in the soil environment. © 2016 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
This chapter draws a link between the volume-oriented forestry measures and the biomass measures used in production ecology. Tools and rules of thumb will be provided to convert the forestry growth and yield values into primary productivity and production efficiencies, and vice versa. In ecological studies in the temperate zone of central Europe, direct physiological measurements of the gas exchange in plants, and indirect estimations based on energy balances, litter production or evaporation rates provide approximate values for gross primary production (GPP) of 20–40 tons ha-1 year-1 or 2–4 kg m-2 year-1 and net primary production (NPP) of 10–20 tons ha-1 year-1 or 1–2 kg m-2 year-1 respectively. Forest inventories and long-term experimental plots, on the other hand, report an average growth of merchantable wood volume of 10–20 m3 ha-1 year-1. This chapter explains how to convert wood volume growth data to NPP through multiplication with the specific wood density, biomass expansion factors and turnover rates, and to GPP by adding respiration.
The introduction points out the very specific system characteristics of trees and forest stands which determine the approach and methods to analyse and model forest stand dynamics, growth and yield. Like other disciplines, forest science looks with an ever-increasing spatial and temporal resolution on the functions and structures of woodlands, forest stands, trees, tree organs, plant cells…. This makes it necessary to discuss concepts for bridging the growing gap between an increasing amount of knowledge on structures and processes on temporarily and spatially highly resolved scales (chemical, biochemical, molecular-biological processes), and an information deficit on more strongly aggregated system levels (stand, ecosystem, landscape scale). The reconciliation between progressing reductionism on the one hand and the demand for holistic system knowledge for forest ecosystem management on the other is a general challenge to forest science and other “green sciences”.
: We examined the concordance between vascular plants and macrofungi (grouped into trophic groups) in Mediterranean forest habitats (central Italy). Our goal was to test how consistently plant and fungi groups classify plots in a broadleaf deciduous forest dominated by Quercus cerris. Our hypothesis was that groups of plants can be used as surrogates for the classification of macrofungal communities. The test of concordance comprised two steps: 1) the plant species data sets were subjected to cluster analysis, to obtain three classifications based on presence of all plants, presence and frequency of only woody species; 2) Multiple Response Permutation Procedures (MRPP) was used to test the performance of each plant classification applied to the fungi data sets. The sample scores along the first PCA axis was used to investigate the relationships between compositional patterns. In the concordance analysis, the classification of only woody plants provided better results than the classification obtained with herbaceous and woody plants together. Cross-tests gave the best results when the “woody plants” classification was applied to ectomycorrhizal fungi (EMF) and, to a certain extent, to humicolous saprotrophs (Sh). The ordination analysis indicated that the frequency of woody plants follows a similar spatial distribution to EMF and Sh fungal groups and is therefore expected to discriminate the same environmental gradients. Many EMF exhibit preferences for few (one or two) hosts. Significant associations were found among a greater number of EMF and woody plant species. Woody plants such as Sorbus domestica and Prunus spinosa appear to be associated with many EMF. The combination of a high frequency of Fraxinus oxycarpa and Quercus petraea seems to promote distinct assemblages of EMF and Sh fungi. Then, characteristic assemblages of fungi were found in association with certain tree and shrub combinations.
Anthropogenic disturbances are detrimental to the functioning and stability of natural ecosystems. Critical ecosystem processes driven by microbial communities are subjected to these disturbances. Here, we examine the stabilizing role of bacterial diversity on community biomass in the presence of abiotic perturbations such as addition of heavy metals, NaCl and warming. Bacterial communities with a diversity gradient of 1-12 species were subjected to the different treatments, and community biomass (OD600) was measured after 24 h. We found that initial species richness and phylogenetic structure impact the biomass of communities. Under abiotic perturbations, the presence of tolerant species in community largely contributed in community biomass production. Bacterial diversity stabilized the biomass across the treatments, and differential response of bacterial species to different perturbations was the key reason behind these effects. The results suggest that biodiversity is crucial for maintaining the stability of ecosystem functioning and acts as ecological insurance under abiotic perturbations. Biodiversity in natural ecosystems may also uphold the ecosystem functioning under anthropogenic disturbance.The ISME Journal advance online publication, 13 June 2014; doi:10.1038/ismej.2014.91.
The most appropriate strategy to be used to create a permutation distribution for tests of individual terms in complex experimental designs is currently unclear. There are often many possibilities, including restricted permutation or permutation of some form of residuals. This paper provides a summary of recent empirical and theoretical results concerning available methods and gives recommendations for their use in univariate and multivariate applications. The focus of the paper is on complex designs in analysis of variance and multiple regression (i.e., linear models). The assumption of exchangeability required for a permutation test is assured by random allocation of treatments to units in experimental work. For observational data, exchangeability is tantamount to the assumption of independent and identically distributed errors under a null hypothesis. For partial regression, the method of permutation of residuals under a reduced model has been shown to provide the best test. For analysis of variance, one must first identify exchangeable units by considering expected mean squares. Then, one may generally produce either (i) an exact test by restricting permutations or (ii) an approximate test by permuting raw data or some form of residuals. The latter can provide a more powerful test in many situations.La stratégie la plus appropriée pour générer une distribution de permutation en vue de tester les termes individuels d'un plan expérimental complexe n'est pas évidente à l'heure actuelle. Il y a souvent plusieurs options, dont la permutation restreinte et la permutation d'une quelconque forme des résiduels. On trouvera ici un résumé d'informations récentes empiriques et théoriques sur les méthodes disponibles, ainsi que des recommandations pour leur utilisation dans des applications unidimensionnelles et multidimensionnelles. L'emphase est mise sur les plans complexes d'analyse de variance et de régression multiple (i.e. les modèles linéaires). Dans un travail expérimental, la supposition d'échangeabilité requise pour un test par permutation est assurée par l'assignation au hasard à des unités des divers traitements. Dans le cas d'observations, l'échangeabilité équivaut à supposer que les erreurs, dans une hypothèse nulle, sont indépendantes et distribuées de façon identique. Pour la régression partielle, la méthode de permutation des résiduels dans un modèle réduit s'est avérée la meilleure. Pour l'analyse de variance, il faut d'abord identifier les unités échangeables à l'examen des carrés moyens attendus. Ensuite, il est généralement possible de produire (i) un test exact en restreignant les permutations ou alors (ii) un test approximatif en permutant les données brutes ou une forme quelconque des résiduels. Cette dernière méthode fournit, dans plusieurs situations, un test plus puissant.[Traduit par la Rédaction]
Forest management activities influence forest structure and development, and thereby influence biodiversity. We investigated diversity and function of macrofungi and soil microbes in a Chamaecyparis formosensis forest with light and heavy thinning treatments and control plots, and we compared them with an adjacent broadleaf forest. Principal component analysis was used to separate macrofungal species components exposed to thinning treatments and those in the broadleaf forest. The macrofungal diversity in the broadleaf forest was higher than in the plantations, and the diversity of fungi from the lightly thinned plantation was higher than those from the heavily thinned and unthinned plantations. Denaturing gradient gel electrophoresis profiles showed that soil fungal and bacterial communities were significantly different among the treatments. However, the carbon utilisation patterns of soil microbes did not differ significantly among treatments. Thinning increased the diversity of saprotrophic macrofungi and changed the soil microbial community of the plantation. This finding might be due to the functional redundancy of soil microbes, as there was no significant thinning effect on the soil microbial function through the fourth year after thinning.
Several permutation strategies are often possible for tests of individual terms in analysis-of-variance (ANOVA) designs. These include restricted permutations, permutation of whole groups of units, permutation of some form of residuals or some combination of these. It is unclear, especially for complex designs involving random factors, mixed models or nested hierarchies, just which permutation strategy should be used for any particular test. The purpose of this paper is two-fold: (i) we provide a guideline for constructing an exact permutation strategy, where possible, for any individual term in any ANOVA design; and (ii) we provide results of Monte Carlo simulations to compare the level accuracy and power of different permutation strategies in two-way ANOVA, including random and mixed models, nested hierarchies and tests of interaction terms. Simulation results showed that permutation of residuals under a reduced model generally had greater power than the exact test or alternative approximate permutation methods (such as permutation of raw data). In several cases, restricted permutations, in particular, suffered more than other procedures, in terms of loss of power, challenging the conventional wisdom of using this approach. Our simulations also demonstrated that the choice of correct exchangeable units under the null hypothesis, in accordance with the guideline we provide, is essential for any permutation test, whether it be an exact test or an approximate test. For reference, we also provide appropriate permutation strategies for individual terms in any two-way or three-way ANOVA for the exact test (where possible) and for the approximate test using permutation of residuals.