255 research outputs found
Biodiversity of collembola on green roofs:A case study of three cities in Belgium
Full text linkGreen roofs are often promoted as a mean to counter the negative environmental effects of urbanization on nature and to increase the amount of green space in cities. Green roofs often enhance aboveground biodiversity, especially herbivores and pollinators. However, if and in what way they support belowground biodiversity, and more specifically soil fauna, is rarely studied. Therefore, we evaluated the diversity of a dominant group of soil fauna, Collembola (springtails), on twelve extensive green roofs in three cities in Belgium (Antwerp, Ghent and Hasselt), over a one year period. The roofs differed in height above the ground, surface area, vegetation type, and age, i.e. time since construction. We analysed if these roof characteristics influenced species richness, abundance or diversity of Collembola. In total we found ten species of Collembola. Species richness was not higher on roofs that were larger (habitat area) or closer to the ground (isolation to surrounding soil), indicating that island-biogeographic theory is not applicable to species richness in our study system. However, significant differences in the mean number of individuals (abundance) were found between different months. Collembola taxonomical composition also varied between the roofs, but this variation could not be related to any of the measured roof variables. Roof communities were characterised by hemiedaphic life forms, preferring neutral to semi-moist conditions. Apart from the age of the roof that showed a positive significant impact on the abundance of Collembola present, our results suggested that the collembolan fauna showed no significant differences in abundance, species richness or diversity between roofs with different characteristics. However, we suggest that future studies are needed to investigate whether our findings are applicable to other groups of soil-living arthropods.</p
The unique epicuticular chemistry of Collembola – A cross-species analysis
Full text linkSpringtails (Collembola), tiny hexapod arthropods, are abundant in the soil of most ecosystems, but our knowledge of their secondary metabolites is limited, in contrast to that of insects. In insects, the outer cuticle is usually covered by mixtures of long-chain hydrocarbons serving different functions, such as water regulation or chemical communication. In contrast, the knowledge of the epicuticular chemistry of springtails is scarce. We analyzed the cuticular lipids of 23 species covering different lineages. The often complicated structures were elucidated using gas chromatography/mass spectrometry, microderivatization, and synthesis. In contrast to insects, the terpene biosynthetic pathway is used for many of these lipids, producing unprecedented higher terpenes. In addition, evidence for de novo cholesterol biosynthesis in springtails was found, which is absent in insects. Finally, diverse non-insect linear compounds originating from the fatty acid biosynthetic pathway were identified. Our comparative analysis showed clear differences compared to insects and shed light on phylogenetic relationships.</p
Importance of environmental and spatial components for species and trait composition in terrestrial snail communities
Full text linkAim: Despite the huge diversity of soil animals and their recognized contribution to many ecosystem functions, little is known about the relative importance of factors controlling their abundance and distribution. We examined the relative importance of environmental and spatial factors in explaining the species and functional trait composition of terrestrial snail communities at the level of meta-communities (spatial extent c. 100 × 100 km) in a heterogeneous, intensively used landscape. We hypothesized that both spatial and environmental factors contribute to the variation in community structure across the landscape, but expected environmental variables describing local habitat conditions to be most important. Location: County of Skåne, south Sweden. Methods: We quantified community structure in terms of species composition and as functional trait composition, because functional traits directly link species performance to environmental conditions. To disentangle the unique and shared contribution of environmental and spatial factors to the variation in snail community structure (in terms of species and trait composition) we applied a partial redundancy analysis. Results: Species traits explained more of the variance in community composition than species identity. Snail traits such as tolerance to environmental stress (related to soil moisture content) and niche width were correlated with the main environmental gradient. Environmental variables (i.e. soil moisture content, vegetation characteristics and soil pH) contributed considerably more to variation in community composition (species: 11.4%; traits: 24.9%) than the spatial variables (species: 6.5%; traits: 4.2%). Main conclusions: The results highlight that both environmental and spatial variables are required to understand the relative importance of niche-based and intrinsic population processes as drivers of terrestrial snail community structure. However, at the scale of our study niche-based community structuring explained by the trait–environment relationship is considerably more important than spatial patterning independent of the environment
Food web uncertainties influence predictions of climate change effects on soil carbon sequestration in heathlands
Full text linkCarbon cycling models consider soil carbon sequestration a key process for climate change mitigation. However, these models mostly focus on abiotic soil processes and, despite its recognized critical mechanistic role, do not explicitly include interacting soil organisms. Here, we use a literature study to show that even a relatively simple soil community (heathland soils) contains large uncertainties in temporal and spatial food web structure. Next, we used a Lotka-Volterra-based food web model to demonstrate that, due to these uncertainties, climate change can either increase or decrease soil carbon sequestration to varying extents. Both the strength and direction of changes strongly depend on: (1) the main consumer’s (enchytraeid worms) feeding preferences; and (2) whether decomposers (fungi) or enchytraeid worms are more sensitive to stress. Hence, even for a soil community with a few dominant functional groups and a simulation model with a few parameters, filling these knowledge gaps is a critical first step towards the explicit integration of soil food web dynamics into carbon cycling models in order to better assess the role soils play in climate change mitigation
Trait-based ecology tools in R
No full textThe R materials provided in this page include: (1) the reference manual (in either pdf or html) and (2) all the data necessary to run the examples included in the manual ("data.zip"). This data is divided into the different chapters composing the R material and the reference textbook.Functional ecology is the branch of ecology that focuses on various functions that species play in the community or ecosystem in which they occur. The present R material is accompanying the book “Handbook of trait-based ecology: from theory to R tools” (Cambridge University Press) (https://www.cambridge.org/core/books/handbook-of-traitbased-ecology/D79AC6C55CA7D3977AD297ED30A38EF0 ) which offers the main concepts and tools in trait-based ecology, and their tricks, covering different trophic levels and organism types. The book, and this accompanying R material, are designed for students, researchers and practitioners who wish to get a handy synthesis of existing concepts, tools and trends in trait-based ecology, and wish to apply it to their own field of interest. For 9 of the 12 chapters of the book, specific R material is presented here. Exercises specifically designed to be run in R, are included, along with accompanying on-line resources including solutions for exercises and R functions, and updates reflecting current developments in this fast-changing field. This R material includes different type of indices of biodiversity and the typical toolbox for a functional ecologist. Based on more than a decade of teaching experience, the authors developed and improved the way theoretical aspects and analytical tools of trait-based ecology are best explained and introduced to readers.Composing this handbook has been made possible by the support of many institutions, including the Spanish National Research Council (CSIC), the University of South Bohemia (USB), the Institute of Botany of the Czech Academy of Sciences (IBOT), the Vrije Universiteit Amsterdam, the Groningen institute of Evolutionary Life Sciences, the University of Tartu (UT), the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) and the Federal University of Rio de Janeiro (UFRJ).Ch1. General introduction.-- Ch2: trait data.-- Ch3: trait dissimilarity.-- Ch4: Multivariate) species levelresponses.-- Ch5: community weighted mean (CWM) and functional diversity (FD).-- Ch6: intraspecific trait variability.-- Ch7: null models.-- Ch8: traits and phylogeny.-- Ch9: linking traits to ecosystem functions.-- Ch10: raits and trophicinteractionsN
Mixed forests with native species mitigate impacts of introduced Douglas fir on soil decomposers (Collembola)
Full text linkForest ecosystem management requires the conservation of associated biodiversity. Enriching native forests with economically valuable conifer species provides economic gains and meets the increasing societal demand for timber but may threaten biodiversity. Soil sustains most of forest biodiversity, but the impact of changes in tree species composition, including native and non-native species, on soil invertebrates remains little studied. We investigated the impact of different forest types on the taxonomic and functional composition of springtail communities (Collembola, Insecta), an abundant and diverse microarthropod group inhabiting litter and soil. Using native Fagus sylvatica (European beech) as reference, we compared Collembola communities with native but range-expanding Picea abies (Norway spruce) and non-native Pseudotsuga menziesii (Douglas fir) as well as beech–conifer mixtures. The abundance of Collembola was higher in Norway spruce than in European beech, with little difference among the other forest types. Further, the taxonomic and functional composition of Collembola was shifted to more parthenogenetic species at sandy sites, stressing the importance of regional factors such as soil type and climate in structuring Collembola communities. Collembola communities in Douglas fir were more pigmented and distributed to the surface, resulting in a lower proportion of euedaphic Collembola compared to European beech forests. In mixed forests, the impacts of Douglas fir on euedaphic Collembola were reduced, suggesting that negative effects of introduced tree species on soil animal communities might be alleviated by limiting Douglas fir to enrichment plantings only. Overall, the results indicate that vertical distribution in soil and morphological traits of Collembola help to better understand the changes in decomposer communities due to planting non-native tree species.</p
Variability in Soil Food Web Structure Across Time and Space
No full textThis chapter focuses on the variability of soil food webs. Information on temporal and spatial heterogeneity is crucial for understanding how soil food webs and soil biodiversity affect key ecosystem processes. Surprisingly little is known about spatial and temporal variability in soil communities and food webs. Variability in food webs has most often been studied in aquatic ecosystems. Sensitivity analyses of soil food web models have shown that small changes in the biomass of particular groups-for example, basal organisms or certain predators-may have a marked and disproportionate effect on soil processes, such as decomposition and mineralization of nutrients. Variability in species composition may not be clearly related to food web variability and ecosystem functioning, because of species redundancy and complementarity within functional groups, and because the scales of spatio-temporal changes in the abundance or biomass of many functional groups are very small compared to the scales at which ecosystem functioning is relevant to the study
Litter mixture effects on nitrogen dynamics during decomposition predominantly vary among biomes but little with litter identity, diversity and soil fauna
Full text linkNitrogen (N) is essential for net primary production, with much of the required N in terrestrial ecosystems derived from recycling via litter decomposition. The diversity and identity of plant species and decomposer organisms affect N cycling during litter decomposition, yet the generality and magnitude of these effects remain uncertain. To fill this gap, a decomposition experiment with four leaf litter species that differed widely in initial litter quality was conducted including single species and all possible multispecies mixtures, with and without microarthropods access across a broad latitudinal gradient covering four major forest biomes of the Northern Hemisphere. The results showed that leaf litter N dynamics (both N loss and N immobilization) in single species treatments depended primarily on litter species identity and the local environmental context. We found strong mixture effects, that overall tended to increase N loss and to reduce 15N transfer. The relative mixture effects on N dynamics differed among forest biomes, but were little affected by the other factors we manipulated. The N loss of individual litter species in mixtures not only depended on litter identity and soil microarthropod access, but also on forest biomes; while 15N transfer depended strongly on litter mixing, independently of litter species richness or composition of the mixtures. Litter N dynamics were mainly driven by a small subset of litter traits, regardless of species richness and microarthropod access. Overall, our results highlight that litter mixture strongly affects N dynamics during decomposition, with the mixture effects predominantly varying among forest biomes but little with litter identity, diversity and microarthropod access. To improve predictions on how changes in tree species composition and diversity may impact nutrient dynamics in forest ecosystems in face of increasing N deposition, interactions between litter and soil but also within litter mixtures need closer attention.</p
Meta-analysis reveals that vertebrates enhance plant litter decomposition at the global scale
No full textThe dataset consists of comprehensive information on litter mass loss, elemental recycling (specifically nitrogen and phosphorus release rates), and associated environmental factors. The data was collected using standardized methods and includes details such as study location coordinates, climatic conditions (temperature and precipitation), ecosystem types (terrestrial and aquatic), study subjects (species identity), litterbag specifics (exclusion method and mesh size), and litter tissue types (woody and non-woody). Missing climatic data were obtained from the WorldClim database. The dataset comprises 1568 sets of pairwise comparisons, with 1060 for plant decomposition, 360 for nitrogen release, and 148 for phosphorus release. This comprehensive dataset serves as a valuable resource for studying litter decomposition, nutrient cycling, and the interplay between environmental factors and decomposition processes
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