1,721,023 research outputs found
Use of microarthropods to evaluate the impact of fire on soil biological quality
No full textEdaphic (i.e. soil dwelling) microarthropods play crucial roles in soil ecosystem services. Fire is a widespread form of disturbance with severe effects on soil invertebrates. Research on the effects of fire on soil arthropods, however, has been mostly focused on surface-active species. Information on the effects of fire on strictly edaphic invertebrates is limited. Thanks to their variable degree of specialization to the edaphic life, soil microarthropods can be used to evaluate soil quality and how it is affected by disturbance. We used an index of soil biological quality based on microarthropods (QBS-ar) to assess the effects of wildfire in three habitats (a natural beechwood, a grassland and a conifer reforestation) in a burnt upland plain in Central Italy, one year after the fire event. Fire affected significantly soil biology quality. In all habitats, burnt soils had a biological quality about 1.4 lower than the respective unburnt soils. Sampling period did not affect QBS-ar values. QBS-ar values varied among habitat types, being highest in the beechwood, lowest in the pinewood, and intermediate in the grassland. These findings indicate that the QBS-ar approach can be profitably used to evaluate the impact of fire on soil biology quality and stress the poor performance of planted conifers in terms of soil quality
Using Yearly-Resolved Time Series to Disentangle Interannual Variability, Directional Change, and Pseudoturnover in Plant Community Composition
Full text linkQuestions: Change in species composition over time is the result of both interannual variability, that is, year-to-year fluctuations due to weather patterns or demographic processes, and directional change, following succession or changing climatic conditions. Quantifying each component is difficult due to the confounding effects of pseudoturnover (i.e., apparent turnover due to observer error). Can yearly-resolved vegetation plot time series be used to quantify the relative contribution of these components of change, while controlling for pseudoturnover?. Location: A European beech (Fagus sylvatica) forest in Central Apennines, Italy. Methods: We developed an approach based on matrix decomposition and PERMANOVA to disentangle the effect of pseudoturnover, directional change, and interannual variability across nine permanent vegetation plots resurveyed for thirteen consecutive years, comparing the herb layer in a newly formed canopy gap, at the gap margins, and in the forest interior. We used helical graphs, generalized linear models, and non-metric multidimensional scaling to compare the timing and pace of vegetation change. Results: Interannual variability and directional change accounted for similar shares of overall variation (26.7% and 28.9%, respectively). While pseudoturnover accounted for a modest 0.4%, ignoring it would result in a substantial overestimation of interannual variability. Overall, the herb layer reacted vigorously to disturbance-triggered changes in light conditions. Species richness increased from 11 to 23.3 in canopy gaps but remained stable at the gap margin and in the forest interior. The rate of change was 3.0 species/year immediately after disturbance and slowed down to 0.3 species/year after 11 years. Conclusions: The composition of the herb layer varied substantially in the study period and showed a marked year-to-year variation even in the forest interior, where light conditions were relatively stable. A proper estimation of the interannual variability of vegetation, while crucial to benchmark the effects of disturbance in forests, should account for the confounding effect of pseudoturnover
Diversity of european habitat types is correlated with geography more than climate and human pressure
Full text linkBIOME (Biodiversity and Macroecology Group) Group was partially supported by the H2020 SHOWCASE (Grant agreement No 862480) and by the H2020 COST Action CA17134 ‘Optical synergies for spatiotemporal sensing of scalable ecophysiological traits (SENECO)’.Cervellini, M., Di Musciano, M., Zannini, P., Fattorini, S., Jiménez-Alfaro, B., Agrillo, E., Attorre, F., Angelini, P., Beierkuhnlein, C., Casella, L., Field, R., Fischer, J.-C., Genovesi, P., Hoffmann, S., Irl, S.D.H., Nascimbene, J., Rocchini, D., Steinbauer, M., Vetaas, O.R., Chiarucci, A
Dispersal ability of threatened species affects future distributions
No full textTo track future climate space, seed dispersal will be essential for plants, but dispersal ability is rarely measured or incorporated into species distribution models. Species distribution models (SDMs) can rank habitat suitability at a local scale, and they may be a valuable conservation planning tool for rare, patchily distributed species. Dispersal is essential for species to survive the threats of habitat destruction and climate change. Combining dispersal ability and habitat suitability at the landscape scale is important to understand and predict species spatial responses to environmental change. This study analyzed future species distributions based on habitat suitability and dispersal scenarios for 7 endangered and vulnerable taxa, using SDM and dispersal ability to predict the range of species distribution across central Italy in the near future 2050. Species distribution models (Ensembles of Small Models, ESMs) were carried out using 19 bioclimatic environmental variables downloaded from WorldClim 1.4. The study identified the most suitable area for this species in the central Apennines. The innovation of this study is the combination of SDMs with dispersal ability based on measured traits of local populations of rare species and subspecies. The main results show a combination of climate change with dispersal ability strongly affects the future potential distribution of the rare species. Thus, obtaining suitable and accessible areas in the near future possible is possible to identify the high suitable sites for the reinforcement of the natural population, ensuring habitat connectivity
Community assembly along climatic gradient: Contrasting pattern between- and within- species
No full textGrime's CSR classification of functional strategies in terms of competitors, stress-tolerators and ruderals provides a helpful framework for understanding and predicting vegetation responses to environmental changes. To evaluate the importance of alternative processes that structure plant communities, it is useful to disentangle the community functional variation into interspecific and intraspecific components and assess their degree of co-variation. Few efforts have been made to investigate the habitat filtering theory in all the interspecific and intraspecific components of a plant community. We hypothesized that under intense climatic conditions, such as drought and cold, functional diversity would decrease towards the dominance of stress tolerant strategies, and that such trends would be reinforced by similar variation at the intraspecific level. We investigated the effect of climatic variation on functional diversity and on community-weighted mean along an elevation gradient in central Italy that ranges from dry and warm climatic conditions at lower elevation to cold and moist ones at higher elevation. We ran regression models to disentangle the total community components for both functional diversity and community-weighted mean into interspecific effect, intraspecific effect and their covariation along the climatic gradient. Our observations were in line with the theory of habitat filtering: we found lower diversity of the Grime strategy for species at both warmer and colder climatic conditions, with dominance of the stress-tolerant strategy. Similarly, the intraspecific effect was lower in cold conditions but higher under drier conditions, which seems to indicate that different processes act at the level of individuals. Given the important intraspecific variability observed in this study, it can be proposed that investigations of vegetation communities should take the role of intraspecific variability into greater consideration
Elevational patterns of plant dispersal ability in Southern Europe
No full textDispersal ability is a functional trait crucial to understand the distribution and spatial dynamics of plant species. This trait influences the abilities of a species to colonize, or thrive, in a region and thus play a central role on its distribution. We investigated the relationship between plant dispersal ability and elevational distribution (within southern Europe). Algorithms combining different plant dispersal traits, such as seed mass, release height, terminal velocity, growth form and dispersal syndrome, were used to estimate dispersal kernels of 929 vascular plant species along elevational gradient. Finally, we calculated Rao’s functional diversity (FD) by analysis of standardized effect size and community mean (CM) for the dispersal distances. The main results show that species, along the elevational gradient, show different dispersal capacity. The greatest dispersal ability was detected at intermediate elevation, while a reduction in dispersal ability along with a convergence in functional diversity was observed with increasing elevation. These results can be explained by variation in environmental constraints along the elevational gradient. Thus, we conclude that short-distance dispersal is crucial in a stressed environment, while long-distance dispersal ability is advantageous to colonize new habitats where environmental constraints are weak
Seed germination and conservation of two endemic species from Central Apennines (Italy)
Full text linkThe Mediterranean mountains are one of the most threatened ecosystems in Europe, and endemic species are a significant feature of this environment.
The definition of germination protocols for endemic, rare or threatened species is an important step for their conservation. The aim of this work
was to analyze seed germination of Phyllolepidum rupestre Ten. Trinajstić and Crepis magellensis F. Conti & Uzunov, two endemic species growing
in small populations in the Majella Nation Park (Central Apennines, Italy). The effects of temperature (5, 10, 15, 20, 25, 25/10 and 20/10°C), irradiance
and gibberellic acid (250 and 500 ppm) on seeds germination were considered. A protocol for the in situ reintroduction was also developed.
The results highlight a significant effect of temperature on seed germination. In particular, seed germination for P. rupestre and C. magellensis was
70.58 ± 3.75 % and 97.30 ± 3.13% at 20°C, respectively. These protocols can be used in reinforcement projects for wild populations
Seed germination reports for Policy species in the central Apennines
Full text linkThe germination ability of four policy species from the Central Apennine were studied: Astragalus aquilanus, Iris marsica, Jacobaea vulgaris subsp. gotlandica, Klasea lycopifolia. Mature seeds were collected in the field, within an elevation range of 365–1932 m a.s.l. Different experimental conditions were tested and the best methods with optimal germination results are provided and compared for each species. First germination records are given for the investigated taxa
A sampling strategy for assessing habitat coverage at a broad spatial scale
No full textThe quantitative assessment of habitat conservation status is a major task for European Union member states in compliance with Council Directive 92/43. One goal of the European 2030 Biodiversity Strategy is the effective management of habitats that show declining trends. While various approaches have been adopted for national assessments, there is no consensus on how to achieve common statistically sound estimates of the criteria indicated by the EU Directive for the evaluation of the status and trend of habitat types. Here, we present an adaptive monitoring approach based on a two-phase sampling scheme to estimate the coverage of EU terrestrial habitat types, which is one of the four criteria indicated by the Habitats Directive. We used 9 habitats distributed among different EU member states choosing Italy as a case study. The development of the methodological approach is described, and a simulation study was performed to check the precision of the coverage estimators accounting for the lack of sampled data (nonresponse treatment), subregions and sustainable sampling effort. We found that our two-phase sampling approach has the potential to increase precision in estimating the coverage of habitat types (approximated at 1 ha cell size) with respect to the precision achieved by simple random sampling without replacement, which is the simplest sampling approach. Adopting a small sampling fraction (⩽0.04%) of the survey area, the relative standard errors ranged from 7 to 15% for common habitats whose presence is strongly correlated with the habitat suitability scores furnished by an expert team. In the challenging context of a “mandated” monitoring type, our approach provides sound statistical estimates of habitat coverage with the possibility of applying a standardised and transferable sampling scheme that is easily repeatable over time
Temporal beta diversity patterns reveal global change impacts in closed mountain grasslands
Full text linkGlobal changes are recognized as one of the main drivers of biodiversity changes over time, especially in mountain ecosystems. A key approach to detect and investigate the effect of climate and land use change on these ecosystems is represented by vegetation surveys. In this study, based on the resurvey of historical vegetation data, we assessed temporal beta-diversity patterns within and between subalpine and alpine vegetation types in the Dolomiti Bellunesi National Park. Resurvey was focussed on plots sampled in four main vegetation types: 1 and 2) Mesophytic and xerophytic grasslands on neutral or base-rich soils respectively dominated by Sesleria caerulea and Carex sempervirens and by Sesleria caerulea and Helictotrichon parlatorei; 3) Acidophytic grasslands dominated by Nardus stricta; 4) Snowbeds with dominance of dwarf willows (Salix herbacea or S. retusa) or Luzula alpinopilosa. Our results revealed a pattern of floristic homogenization in grasslands and snowbeds indicating a decreasing heterogeneity, both within and between different vegetation types that can be associated with different components of global change. The highest temporal beta diversity and floristic homogenization were detected in snowbeds. In general, the magnitude of temporal changes differ between communities, thus claiming for conservation activities that are tailored to each vegetation type
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