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Abstract: The impact of geology, climate, soil type and vegetation on forest humus forms was studied in the Veneto Region (northern Italy). A total of 352 study sites were compared by Redundancy Analysis (RDA). Humus forms were described by the structure (micro-, meso-, or macro-aggregated) of the organo-mineral A horizon, by the thickness of litter horizons and by their nomenclature, which followed the morpho-functional classification recently proposed for inclusion in the WRB-FAO. The size of aggregates within the A horizon was distributed along a common gradient embracing geology, climate, soils and vegetation. Macro-aggregation (as opposed to micro-aggregation, meso-aggregation being intermediate) was favored by carbonated (as opposed to silicated) parent rocks, warmer climate associated to lower elevation, lower soil acidity, deciduous (as opposed to coniferous) forest vegetation and relatively high clay content. The amphi group of humus forms, associated with carbonated substrates in Esalpic and Mesalpic climate districts, was distributed according to thickness of litter horizons along a gradient of soil stoniness. Biological reasons for the observed environmental influences on the size of soil aggregates, a criterion of humus form classification, were discussed to the light of knowledge on annelid (earthworm and enchytraeid) ecology. Humus forms can be easily identified and classified on the field, using a table included in the article. Our results can be used for mapping the distribution of forest humus forms in the Veneto Region, implying a better understanding of carbon cycling processes in the frame of present-day global warming. [Copyright &y& Elsevier]

Aim Certain species have few living relatives (i.e. they occupy low clade ranks) and hence they possess high conservation value and scientific interest as unique representatives of ancient lineages. However, we do not know whether particular environments favour the maintenance of low clade ranks or whether the distribution of environments across the globe affects the global distribution of clade ranks and, hence, evolutionary uniqueness. In this study, we tested whether and how harsh environments decrease the clade ranks of the species that inhabit them. Location Global. Methods We described the phylogeny of the collembolan genus Willemia by a parsimonious method based on 52 morphological characters and estimated the species' use of harsh environments (polar, high mountain, desert, polluted, waterlogged, saline and acidic) from 248 publications. Results We found that the use of different types of harsh environments is maintained among close relatives and has similar phylogenetic signals (except for the use of salinity). The use of harsh environments might therefore affect the diversification of lineages. Correcting for the phylogenetic non-independence of species, we found that species using harsh environments have comparatively low clade ranks. We also found that species using harsh environments occur almost exclusively on former Laurasian continents and that, as a statistical consequence, Laurasian species tend to have lower clade ranks. Main conclusions We suggest that harsh environments maintain low-clade-rank species by decreasing, simultaneoulsy or successively, extinction and speciation, which may eventually explain the major variation in clade rank across the globe. [ABSTRACT FROM AUTHOR]

In Neotropical forests, dung beetles act as efficient secondary dispersers of seeds that are dispersed primarily by red howler monkeys. Here, we investigated the origins of soil seed bank variability in relation to monkey and dung beetle activity, to assess the impact of dung beetles on seed fate, and their adaptability to resource availability. This question is important to better understand the process of tree regeneration, and is especially timely in the current context of threat to primates. We characterized soil seed bank structures in sites differing in monkey frequentation, and conducted field experiments with artificial beads to monitor bead fate. We also conducted experiments on specific roller and tunneller beetle species to examine bead processing behavior and its variability among and within species. We found that seed number and diversity increased with monkey frequentation, but seed viability was optimal under moderate monkey frequentation. We showed for the first time that dung provisioning yielded higher beetle activity in sites more often visited by monkeys, which calls for further investigation to understand the mechanisms of attraction to resource and potential spatial structuration of beetle populations. Although all beetle species involved in the experiments actively excluded beads from dung reserves, selectivity was higher for small than large beetle species, and for large compared to small bead sizes. It also increased when per-capita dung resource decreased, suggesting that intraspecific competition could alter seed fate. Altogether, our results support a major role of dung beetles in soil seed bank structure and dynamics. They reveal interesting interspecific variability within the dung beetle community and a complex interplay with primary dispersal. [ABSTRACT FROM AUTHOR]

Abstract: We investigated by linear gradient analysis (RDA) the relationships between forest humus forms (9 humus forms and the Humus Index) and 148 variables describing geology, climate, soil type, geography and the floristic composition of forest canopies, using 3441 plots of the EcoPlant database covering the whole French territory. Among these variables, geology (alkaline vs acidic substrate) and climate (warm/dry vs cold/rainy) were the major determinants of humus forms, scaling mull humus forms from eumull to dysmull and opposing them to mor/moder, while the contribution of tree canopies was negligible. This trend was verified by partial RDA with environment or abundance of tree species from forest canopy as co-factors. The original position of amphi was confirmed: it was the only humus form not included in the gradient of increasing biological activity ordinated according to climate and geology. Results and possible forecasts of humus forms according to global warming were discussed to the light of existing knowledge. [Copyright &y& Elsevier]

Invasive plants are recognised as a major threat to biodiversity. Although they are well-established in natural areas, the supposed negative impacts of invasive plants upon communities and ecosystems have so far been poorly investigated in urban areas, where invasions are a main issue for ecologists and for urban planners and managers. We propose to assess the effects of an invasive species along an invasion gradient in a typical urban habitat. We focused on the Japanese knotweed ( Reynoutria japonica Houtt.), a widespread invasive species in Europe and North America. We considered eight urban wastelands invaded by this species in the heart of the Greater Paris Area, France. On each site, we ran four transects from the centre of the Japanese knotweed patch towards the uninvaded peripheral vegetation. We recorded the flora using the line intercept method, and several soil parameters (thickness of A horizon, abundance of earthworm casts, topsoil Munsell value, pH) every metre along each transect. The A horizon was thicker and the topsoil darker under R. japonica canopy. Thus, this invasive plant species seemed to influence soil organic matter pool. However, our results also steadily showed that R. japonica locally excluded and/or severely reduced the cover of many plant species through competition. Our study clarified the local effects of R. japonica: an influence on the soil organic matter, and a severe negative impact on wasteland plant communities. We suggest implications in both conservation and restoration ecology. [ABSTRACT FROM AUTHOR]

We studied the impact of dung deposition by the red howler monkey (Alouatta seniculus), and subsequent burial by dung beetles and other biotic and abiotic processes, on the distribution of small seeds in the soil seed bank (Nouragues Reserve, French Guiana). Seeds were collected from 54 soil samples taken under three sleeping sites and adjoining control sites, at three positions according to a fixed grid and at three different depths (0–2, 2–4 and 4–6 cm). Despite large differences between the three sites, defecation areas (latrines) were found to contain more seeds and higher seed diversity than control areas. Seed density decreased with depth in the top 6 cm in two sites but not in the third. Shannon diversity decreased with depth in both defecation and control areas. Differences in the distribution of seeds of different species were found according to size and growth habits (pioneer vs non-pioneer species). The viability of seeds, ascertained from toughness and integrity of the seed coat, varied according to depth, site and defecation. Seed viability was on average higher in defecation areas compared with control areas. [ABSTRACT FROM PUBLISHER]

Abstract: We analysed by an optical method (the small volume method) the composition and the vertical distribution of an organic soil which accumulated over an old petroleum tar deposit. The study site was an oil refinery now colonised by woody vegetation since the time of abandonment (1964), located at Merkwiller-Pechelbronn (Alsace, France). Comparisons were done with a nearby unpolluted control plot under similar vegetation. The humus form over the tar deposit was described as an Hemimoder. It was characterised by fine fragmentation of litter, darkening of tree leaves with depth and a dense mycelial mat associated with an ectomycorrhizal root system. Faunal activity was dominated by enchytraeids. The Mesomull described at the control plot was characterized by fast recycling of litter and earthworm activity. [Copyright &y& Elsevier]

Abstract: In previously published papers it had been demonstrated that at the local level the species richness of soil springtail communities was negatively influenced by landuse diversity. When the dispersal rate of soil animals was taken into account, quite opposite trends were displayed by species having poor or high dispersal capabilities. At the local level, species with short legs, non functional jumping apparatus and reduction of visual organs were distinguished against by landuse diversity, while species with long legs, functional jumping apparatus (furcula) and complete eyes, thus able to disperse at the soil surface, were not. It was verified, through aerial photographs taken 50 years ago, that landuse changes, expected to be more frequent in heterogeneous landscapes, may contribute to explain this phenomenon. [Copyright &y& Elsevier]

Plant communities are affected by land-use and landscape heterogeneity and can be used as indicators of environmental change. At small-scale, species composition and species richness of plant communities are influenced by local environment and by diaspores from the surroundings. Thus, they reflect the influence of both land-use type and land-use diversity. Plant community composition was studied along a gradient of agricultural disturbance in the Morvan Regional Natural Park (Burgundy, France). Six landscape units of 1 km2 were selected along a range of increasing land-use intensity. Sixteen 0.2 m2 sampling plots per unit were selected according to a grid-based design to estimate the percent cover of all plant species. Pattern analysis showed that local species richness increased from woodland to crop to grassland, and also increased with land-use diversity. Local plant biodiversity was maximized under intermediate disturbance intensity and minimized at low (woodland) and high (crop) disturbance levels. [Copyright &y& Elsevier]

In French Guiana, inselbergs in the form of granite outcrops rise abruptly from the surrounding rain forest. They constitute isolated islands of a special type of vegetation restricted to this peculiar substrate. Shrub granitic vegetation, organized in thickets on open exposed rocks of inselbergs, are described using the Braun-Blanquet method combined with Correspondence Analysis. This phytosociological study revealed only one particular shrub community on each inselberg, including predominantly evergreen and sclerophyllous shrubs, especially microphanerophytes, belonging to the Clusiaceae, Myrtaceae and Bornbacaceae. These outcrop communities exhibit species endemic to the Guianas region and also species rare in French Guiana. Affinities with flora of other inselbergs and vegetation types in South America are examined and discussed. Reasons for observed floristic and structural changes in each community are also discussed. [ABSTRACT FROM AUTHOR]

Recommends humus index as an integrated tool for the assessment of forest floor and topsoil properties. Correlation between the index and various morphological and chemical variables describing forest floors and topsoil profiles; Potential application in bulk assessment of organic matter accumulation.

A biofertilisation assay was conducted in Maripasoula (French Guiana), testing the effects of three different organic amendments (manioc peels, sawdust and wood charcoal) and the inoculation of the endogeic earthworm Pontoscolex corethrurus on pod production of Vigna unguiculata sesquipedalis and on soil chemical properties (pH, C, N, total and exchangeable P and K). Pod production was highest with manioc peels as available P increased in the soil. Wood charcoal also had a beneficial effect on pod production as it decreased acidity and increased the C:N ratio in the soil. In sawdust-amended soil, pod production did not differ from that in unamended soil. Inoculation of earthworms at a density of 80 sub-adults m–2 did not significantly affect either pod production or soil nutrient content directly, although it increased the positive effect of manioc peels on pod production. Soil nutrient content, pod production and earthworm density at the end of the experiment were negatively correlated with soil moisture and positively with each other. Despite the strong effect of moisture, this assay demonstrated an interaction between the earthworm P. corethrurus and the legume V. unguiculata sesquipedalis mediated by soil nutrient content and organic matter inputs. We conclude that manioc peels improved soil P availability and were an interesting amendment for legume crops. We discuss also the effect of earthworm inoculation. [ABSTRACT FROM AUTHOR]

Decomposition processes in tropical semi-evergreen forests are still poorly understood. The influence of soil properties and litter quality on decomposition rate was studied in two semi-evergreen forests of Guadeloupe, a forest plantation and a secondary forest, located on different soils. Leaf litter of four tree species was enclosed in litterbags for a 14-month period. Non-linear correlations were calculated between mass loss and the concentration of major leaf components (soluble C, N, lignin, cellulose, tannins, total soluble phenols) in order to determine the best predictor of leaf litter decomposition. Soil physico-chemical properties and ratios between some of the above-mentioned litter quality parameters were also examined as mass loss predictors. In addition, non-linear correlations were calculated between mass loss and litter quality parameters, at successive periods. Litter quality was the main determinant of litter decomposition in the studied forests. Several litter quality parameters were correlated with leaf disappearance, varying according to stages of decomposition. Between 1 month and 2.5 months, the mass loss was correlated negatively with the initial phenol content and with initial lignin:N and (lignin+phenol):N ratios. From 2.5 to 5.5 months, the mass loss was correlated negatively with the initial phenol content and positively with the initial cellulose content. At later stages of decomposition (9–14 months), the mass loss was correlated negatively with the initial tannin content. Differences in soil characteristics and fauna did not seem to be enough to affect decomposition. [ABSTRACT FROM AUTHOR]

The author regrets at the beginning of the sub-section "Sex pheromones" (page 428 of the published version) within the section "The use of pheromones, allomones and kairomones by Collembola" [ABSTRACT FROM AUTHOR]

The present opinion paper suggests that springtails, which can live above- and/or belowground according to species requirements, have two strategies at their disposal to face environmental hazards, called 'move' or 'change'. Species with poor dispersal capacity, often parthenogenetic, and living mainly in a confined environment, have to adapt themselves by increasing their phenotypic plasticity or letting the environment selecting or adding favourable mutations. Conversely, species with a high dispersal capacity, often sexual and living in a more open environment, may emigrate and immigrate without the need to become better adapted to changing environmental conditions. Advantages and disadvantages of these two tactics are reviewed and their prospective responses to global changes are compared on the light of existing knowledge on this microarthropod group. [ABSTRACT FROM AUTHOR]

Humusica 1 and 2 Applied Soil Ecology Special issues are field guides for humipedon classification. Contrary to other similar manuals dedicated to soil, the objects that one can describe with these guides are living, dynamic, functional, and relatively independent soil units. This is the reason to why the authors dedicated the whole article number 2 to functional considerations even before readers could go in the field and face the matter to be classified. Experienced lectors can overstep many of the sections reported in this article. If the titles of sections “1 A functional classification", "2 What is a humus system?"and "3 Energetic considerations in terrestrial systems” stimulate the reader’s curiosity, then we suggest to pass through them. Otherwise, only section “4 Climatic, plant litter, or nutritional constraints?” is crucial. Readers will understand how the soil works in terms of litter and Carbon accumulation, which one(s) among climatic, vegetational, or geological factors that intervene and strongly affect the formation processes of terrestrial (oxygenated) soils. The article concludes with a debate about a tergiversated question: can temperature influence humus decomposition? Preceding statements were used for explaining how the biological soil net can store in the soil a maximum of energy in the form of SOM, by raising a plateau partially independent of climatic conditions. [ABSTRACT FROM AUTHOR]

In recent years, three sections (Humipedon, Copedon and Lithopedon) were recognized in the soil profile. It was then possible to link the first and most biologically active section to the characteristics of the environment and soil genesis. In particular, it is now possible to distinguish organic horizons, mainly produced by arthropods and enchytraeids in cold and acidic or dry and arid environments, from organo-mineral horizons produced by earthworms in more temperate and mesotrophic environments. Each set of horizons can be associated with a humus system or form, with important implications for forestry. Anecic/endogeic earthworms and Mull or Amphi systems are more abundant in the early and late stages of sylvogenesis; by completely recycling litter, earthworms accelerate the availability of organic and inorganic soil nutrients to roots and pedofauna. On the other hand, arthropods and Moder or Tangel systems characterize the intermediate stages of sylvogenesis, where thickening in the organic horizons and the parallel impoverishment/reduction in the underlying organo-mineral horizons are observed. Recognizing the humus system at the right spatial and temporal scale is crucial for the biological management of a forest. This article includes a data review, new data from a doctoral thesis, and recent comparisons of Italian and French investigations. [ABSTRACT FROM AUTHOR]

Born in Trento (Italy, 2003) for the purpose of standardising vocabulary and units of humus form classification, after publishing a first synthetic classification e-book (Zanella et al. 2011) they do not cover all site conditions in the European area. Although having basic concepts and general lines, the European (and North American, Canadian, the Humus group decided to use its classification for handling global change (Zanella and Ascher-Jenull 2018). The process is detailed in many scientific articles published in three Special Issues (Humusica 1, 2 and 3) of the journal Applied Soil Ecology. Conceptually, the whole of Humusica answers three crucial questions: A) What is soil? Soil is a biological ecosystem. It recycles dead structures and implements mineral material, furnishing more or less re-elaborated organic, mineral and organic-mineral elements to support living organisms. Article chapters: 1. Essential vocabulary; 2. Soil covers all the Earth's surfaces (soil as the seat of processes of organic matter storage and recycling); 3. Soil may be involved in the process of natural evolution (through organisms' process of recycling biomass after death). B) If soil has a biogenic essence, how should it be classified to serve such managerial purposes as landscape exploitation or protection? A useful classification of soil should consider and propose useful references to biologically discriminate soil features. Article chapters: 4. Soil corresponds to a biogenic structure; 5. TerrHum, an App for classifying forest humipedons worldwide (a first attempt to use a smartphone as a field manual for humus form classification). C) How can this soil classification be used for handling the current global change? Using the collected knowledge about the biodiversity and functioning of natural (or semi-natural) soil for reconstructing the lost biodiversity/functioning of heavily exploited or degraded soils. Article chapters: 6. Agricultural soils correspond to simplified natural soils (comparison between natural and agricultural soils); 7. Organic waste and agricultural soils; 8. Is traditional agriculture economically sustainable? Comparing past traditional farm practices (in 1947) and contemporary intensive farm practices in the Venice province of Italy. [ABSTRACT FROM AUTHOR]

Some soil scientists or biologists (14, one preferring anonymity) answered the three following questions: (1. Introduction) 2. Why is organic food better (tastes better, is healthier, richer in nutrients, contains less pesticide, etc.) than food produced with hydroponic or intensive farming techniques? 3. In a humipedon, are soil functioning, biodiversity and carbon content three interdependent and intersected aspects of a single ecosystem? In other words, can we treat these aspects as if they were inseparable in a humipedon? 4. Are agriculture and civilization (the society, culture, and way of life) interconnected? All scientists expressed affirmative answers. Nuances or in depth information were also furnished. The article allows to understand the real “agronomic challenge” that the predicted Global Change might represent for humanity. [ABSTRACT FROM AUTHOR]

Graph Guy Vannier passed away on May 16, 2022 in Quincy-sous-Sénart (Essonne, France). He invented a soil fauna extractor based on the behaviour of soil animals in a humidity gradient. Guy Vannier created a rational methodology in soil ecology and biology, working especially on methods for the study of soil microarthropods (springtails, mites). [Extracted from the article]