Soil Invertebrate Communities Research Articles

Impacts of climate change–simulated flooding and drought events–on terrestrial invertebrates (Enchytraeids and Collembolans)

Impacts of soil moisture levels from 10% to 100% on two soil invertebrates.E. crypticus and F. Candida survived at extreme scenarios (10% and 100%).For both species, reproduction was severely reduced in extreme scenarios.Higher adaptative phenotypic plasticity for F. Candida compared to E. crypticus.Knowledge on impacts of climate change on soil invertebrate communities is scarce. Amongst the biggest challenges are the increase in temperature and arid regions, while at the same time, in other parts of the planet, extreme precipitation events and flooding occur. The aim of the present study was to investigate the impacts of drought and flooding in soil invertebrates. Enchytraeus crypticus and Folsomia candida, model ecotoxicology test-species (OECD) were used to assess performance (survival, reproduction, size) in LUFA 2.2 soil moistened to 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% of the soil water holding capacity (WHC). Overall, both species had high tolerance for drought and flooding scenarios, with survival threshold for E. crypticus being between 10% and 90% moisture and for F. candida being between 10% and 100% moisture. Reproduction decreased from moisture ⩽ 30% and >70% moisture. In drought there was a decrease on adults’ size, for both species from ⩽ 30% moisture. The morphological adaptations observed support evidence of adaptative phenotypic plasticity for both species, but highest for F. candida. A redistribution of soil invertebrate species can be expected to occur, this under the present and future climate change scenarios, with new and more tolerant species to prevail in different habitats. This will impact not only soil biodiversity structure, but also its function.

Above- and below-ground field study on the impacts of conventional and alternative mesoplastics on Hordeum vulgare growth and soil invertebrate communities

Plastic plays an important role in agriculture, but its use has become a concerning source of pollution. While new (bio)degradable, alternative plastics are being developed and used as mulching films, their ecological impacts, in particular under field conditions, are not well understood. Furthermore, there is a notable lack of knowledge on how plastic pollution affects soil invertebrate communities. Most existing studies primarily focus on microplastics, often neglecting the impacts of mesoplastics. This study therefore compared the separate effects of two conventional (polyethylene and polypropylene) and two alternative (polyethylene containing biodegradable additives and compostable polylactic acid) mesoplastic films on plant performance (biomass, seed yield) and soil mesofaunal assemblages in a field experiment. The mesoplastics were applied at 0.1% (w/w), prior to soil being planted with Hordeum vulgare (spring barley), which was grown to maturity, for 11 weeks. Generally, there were no measurable differences between the conventional and alternative plastic treatments, however, barley exposed to mesoplastics showed reduced biomass, seed yield, and chlorophyll content, along with increased oxidative stress. Soil fauna, particularly Collembola, had lower richness and abundance when exposed to both plastic types, but assemblage structure and composition remained unchanged after 11 weeks. This study is pivotal in highlighting that both conventional and alternative plastics can similarly affect plant health and soil ecosystems. The evidence provided is essential for refining future risk assessments of agricultural plastic pollution and underscores the urgent need for more sustainable practices and materials in agriculture.

Ecological succession shapes size–density scaling relationships of trees and soil invertebrates

Abstract The widely observed negative scaling relationship between organism size and abundance is predicted to have a universal −0.75 scaling exponent across all life forms. However, factors influencing frequently observed deviations from this exponent, such as ecosystem succession and organism traits, remain poorly understood. We explore the dependence of size–density scaling on ecosystem succession and organism traits by analysing size–density relationships in trees and soil invertebrates across 183 temperate forest plots comprising urban secondary forests, urban old‐growth forests and non‐urban natural forests. Exponents of scaling relationships in urban tree and invertebrate communities progressively steepened with increasing restored (planted) forest stand age as small organisms increased in abundance. In contrast, non‐urban tree scaling relationships flattened during succession with exponents veering away from −0.75, whereas urban tree and invertebrate communities converged towards this prediction in later successional stages. Our results shed light on how the body size structure of tree and soil invertebrate communities spanning multiple trophic levels shift over successional time as the relative abundances of large versus small‐bodied organisms increase. This study emphasises the fundamental influence of organismal traits and ecosystem succession on scaling relationships of organism body size and abundance. Read the free Plain Language Summary for this article on the Journal blog.

Climate change in edaphic systems – Impact of salinity intrusions in terrestrial invertebrates

Amongst climate change’s impacts a major concern is salinization of soils, for example due to saltwater intrusion. The aim of the present study was to investigate in a standard field soil the impacts of soil salinity increase. The purpose was to study this in two soil invertebrates that are key model ecotoxicology test-species, Enchytraeus crypticus and Folsomia candida as surrogate representatives of the soil ecosystem. The exposure followed the standard ecotoxicity OECD (Organization for Economic Cooperation and Development) test guidelines, and the assessed endpoints were survival, reproduction and size. Exposure done in LUFA 2.2 soil, spiked with 0,0.6,1,2,3,4,5,6,8 g NaCl/kg soil dry weight (DW) for E. crypticus (21 days) and 0,0.06,0.6,1,2,3,4,5,6 g NaCl/kg soil DW for F. candida (28 days). There was a similar impact for both species in terms of survival (LC50=4.2 g NaCl/kg soil DW), whereas at the reproductive output level of F. candida (EC50=2.1 g NaCl/kg soil DW) was more sensitive than E. crypticus (EC50=2.4 g NaCl/kg soil DW). Further, size was impacted for F. candida in a monotonic dose-response curve for both adults (EC50=3.5 g NaCl/kg soil DW) and juveniles (EC50=2 g NaCl/kg soil DW), whereas for E. crypticus there was an increase in reproductive output at lower concentrations (0.6–1 g NaCl/kg soil DW). This increased reproduction was associated with a larger size of adults within the same concentration range. Considering the prediction from the climate models, the soil invertebrate community will be affected. As upper soils are likely to have the highest salinity increase due to evaporation, soil surface species, such as the collembolan tested here, are at higher risk. Negative population effects were occurring within salinity levels predicted by climate change models.

The abundant fraction of soil microbiomes regulates the rhizosphere function in crop wild progenitors.

The rhizosphere influence on the soil microbiome and function of crop wild progenitors (CWPs) remains virtually unknown, despite its relevance to develop microbiome-oriented tools in sustainable agriculture. Here, we quantified the rhizosphere influence-a comparison between rhizosphere and bulk soil samples-on bacterial, fungal, protists and invertebrate communities and on soil multifunctionality across nine CWPs at their sites of origin. Overall, rhizosphere influence was higher for abundant taxa across the four microbial groups and had a positive influence on rhizosphere soil organic C and nutrient contents compared to bulk soils. The rhizosphere influence on abundant soil microbiomes was more important for soil multifunctionality than rare taxa and environmental conditions. Our results are a starting point towards the use of CWPs for rhizosphere engineering in modern crops.

Comparative Effects of No-dig and Conventional Cultivation with Vermicompost Fertilization on Earthworm Community parameters and Soil Physicochemical Condition

Because of the numerous ecosystem services provided by soil, such as elemental cycling, food production, and water filtration and storage, this resource requires special protection to maintain total efficiency of these services. However, standard agricultural practices can have a degrading effect, not only on the physical and chemical properties of soil, but may also threaten soil invertebrate communities. Soil macrofauna, and earthworms in particular, play a critical role in soil ecosystems because their activities affect the availability of nutrients for plants, shape soil structure, and significantly impact organic matter dynamics. The present study was undertaken to determine the effects of two systems used in plant cultivation (no-dig and conventional digging). Both used vermicompost as an organic fertilizer and looked at selected characteristics of Lumbricidae groupings and the dynamics of selected soil physicochemical properties. This study was conducted over three years in the same area to ensure that the soil characteristics were the same. The NDG (no-dig) and DG (conventional digging) sites were prepared as appropriate with a perennial hay meadow (MW) used as a control site. An electrical extraction (octet) method was used to collect earthworms. The same six species of earthworm were found at each site: Dendrodrilus rubidus (Sav.), Lumbricus rubellus (Hoff.), Aporrectodea caliginosa (Sav.), Aporrectodea rosea (Sav.), Octolasion lacteum (Örley), and Lumbricus terrestris (L.). Earthworm abundance and biomass were found to be significantly higher at the NDG site compared to DG (NDG > DG; abundance by 24% (p < 0.05), biomass by 22% (p < 0.05)). No significant differences between NDG and MW were shown. Moisture, temperature, and soil organic carbon content likely influenced the abundance and biomass of Lumbricidae. The NDG site showed significantly higher organic carbon and moisture content and significantly lower temperatures than the DG site. The average number of earthworms damaged by digging was 0.85 ind. m−2, but did not significantly affect the other results. Overall, NDG is preferable to DG for enhancing the earthworm and physicochemical parameters of soil.

The Short-Term Responses of Forest Soil Invertebrate Communities to Typhoon Disturbances

Knowledge regarding the response of soil invertebrate communities to typhoon disturbance is limited, although it is known that soil invertebrates are sensitive to forest disturbances and that tropical cyclones (typhoons/hurricanes) are the most destructive natural disasters affecting the structure and function of forest ecosystems. To fill this knowledge gap, soil invertebrates in both litter and topsoil layers were investigated in four representative subtropical coastal forests of eastern China one week before the first typhoon (Hinnamnor) (T1), one day after the first typhoon (Hinnamnor) (T2), one day after the second typhoon (Muifa) (T3), and one week after the second typhoon (Muifa) (T4) in September 2022. Typhoon disturbances decreased the density and taxa abundance of soil invertebrate communities in litter layer, but the first typhoon disturbance increased these values in the topsoil layer. One week after the second typhoon disturbance, soil invertebrate communities in the litter layer showed a gradual recovery trend. Meanwhile, the soil invertebrate communities in the litter layer were more sensitive to typhoon disturbances than those in the topsoil layer. Furthermore, the responses of the soil invertebrate communities to the typhoon disturbances varied greatly with the forest types. The invertebrate densities in the litter layer decreased by 62.1%, 63.53%, 47.01%, and 46.92% in Chinese fir, second broad-leaved, mixed, and bamboo forests, respectively. Particularly, these two non-catastrophic typhoons significantly altered the functional group composition of detrital food webs in the short term, and the proportion of phytophages in detrital food webs in the litter layer increased after the typhoon disturbances. In conclusion, the effects of typhoon disturbances on soil invertebrate communities vary greatly with forest type and soil layer, and soil invertebrate communities can gradually recover after typhoon disturbances. The legacy effects of typhoon disturbances on the functional group composition of detrital food webs may influence carbon and nutrient cycling in forest ecosystems.

Impacts of garlic mustard (Alliaria petiolata, Brassicaceae) invasion on oribatid mites in urban forest soils vary with the size of the invaded patch

Investment in non-native species management should be informed by knowledge of impact, including on native biodiversity and ecosystem function. Oribatid soil mites may be useful to evaluate the impacts of plant invasions since they are bioindicators of disturbance and soil ecosystem health. Still, more research is needed to characterize their responses to plant invasion, especially at the species level. Our objective was to determine the effect of invasion of urban forest understories by an allelopathic weed (garlic mustard, Alliaria petiolata (Brassicaceae)) on belowground oribatid mite species and communities. At two sites in central Alberta (Canada), over two years, we examined adult oribatid (≥ 300 µm) community assemblages, species richness, evenness, diversity, and abundance in plots invaded with garlic mustard and uninvaded plots with native vegetation. Environmental covariates known to be associated with soil invertebrate communities were also evaluated. Results suggest that the spatial extent of the garlic mustard invasion (patch area) mediates its impact on oribatid mite communities. However, there were no community-level impacts when considering invasion as binary (garlic mustard vs. native vegetation). Garlic mustard patch area influenced oribatid community composition and was positively related to species richness and several abundance metrics. The oribatid species we observed benefiting from garlic mustard invasion have been previously associated with disturbed soils. The mechanisms driving these patterns need more research, but we hypothesize they may relate to patch-specific resident times. Site was also a dominant factor influencing oribatid mite communities, and impacts of year, litter depth, and canopy cover were also detected at the species and/or community level. These findings contribute to our understanding of the impact of an invasive weed on bioindicating soil mite communities and species and highlight the importance of considering invasion context, including spatial extent when evaluating the impacts of invasive species on belowground invertebrate communities.

Asymmetric environmental selection on intraspecific body size in Collembola communities along an elevational gradient in northern Japan

Body size is a crucial functional trait that influences the environmental filtering processes of animal communities. However, the role of intraspecific variations in soil invertebrate communities remains poorly understood. In this study, we investigated the influence of environmental changes on intraspecific body size variations in Collembola communities along an elevational gradient in northern Japan, using potential body length in the literature cited and realized body length actually measured. Our hypothesis posits that environmental conditions selectively filtered out smaller nymphs while sparing larger adults of Collembola, as stress tolerance, survival and mortality are directly influenced by body size in response to environmental severity. Calculating size quantiles based on observed realized individual body lengths, we found a stable size hierarchy among species across elevational sites. Species composition was significantly related with elevational gradient, with community-weighted means of smaller quantiles in body length increasing at higher elevations, while those of larger quantiles and adult body size remained unaffected. This suggests that environmental filtering predominantly influences the body size of smaller individuals, such as nymphs, but not larger adults within species. Our findings reveal asymmetric size selection among different life stages in soil animal communities.

Evergreen gymnosperm tree abundance drives ground beetle density and community composition in eastern US temperate forests

PurposeSoil invertebrates are abundant and diverse members of forest ecosystems, contributing in large parts to ecosystem functioning. Understanding drivers of soil invertebrate diversity, density, and community composition is critical to inform management practices as forests face rapid changes in land use and climate. Tree community metrics may help predict invertebrate communities due to their large role in shaping microhabitat and soil conditions. Ground beetles are a large family of soil-dwelling invertebrates comprised of multiple functional groups ideal for tying tree communities to invertebrate communities broadly. Methods Here, we evaluated the effects of tree diversity, density, and functional groups on ground beetle (Carabidae) diversity, density, and community composition in four eastern US temperate forest sites in the National Ecological Observatory Network. Results We found little evidence to support our hypothesis that higher tree diversity and density would, respectively, lead to higher diversity and density ground beetle communities. Instead, evergreen tree abundance strongly shaped ground beetle density and community composition. Specifically, evergreen stands contained a lower density of ground beetles than deciduous stands. Similarly, the relative abundance of predatory ground beetles increased as the relative abundance of evergreen trees increased. Conclusions Our results show that the resource environments created by trees with varying leaf habits are a dominant force driving ground beetle community diversity and density patterns and suggest that future research exploring mechanisms driving this pattern could improve our understanding of plant-soil interactions.

Eucalyptus plantation reduces diversity and disrupts predator-prey correlations of soil invertebrates within Atlantic Forest

Human activities in the Anthropocene have led to the conversion of a significant area of the Earth's surface to agroecosystems, including tree plantations such as eucalyptus. Brazil, as the largest producer of eucalyptus timber, faces the challenge of preserving its rich biodiversity, particularly in the Atlantic Forest biome, which is one of the world's most threatened and diverse. This study aimed to assess the impact of eucalyptus plantation on soil invertebrate communities compared to that of native forest remnants. We sampled ants, beetles, springtails, and spiders as model groups to evaluate the alpha diversity and composition of soil invertebrates in these forests. We also examined trophic interactions between springtails and their potential natural enemies (spiders, ants, and beetles) in both environments. Our results revealed that the abundance and richness of ants and beetles were higher in native forests than in eucalyptus plantations, whereas springtails exhibited a negative response to eucalyptus plantation in terms of abundance, and spiders showed higher richness in eucalyptus plantations. Furthermore, the composition of soil invertebrate communities, with the exception of springtails, was significantly different between eucalyptus plantations and native forests.The correlations between the abundance of springtails and their potential predators (spiders and beetles) were significantly reduced in eucalyptus plantations compared with native forests. Our findings highlight the negative impact of eucalyptus plantation on soil invertebrate diversity and community composition, potentially disrupting predator-prey relationships and emphasizing the importance of preserving native forests to safeguard invertebrate biodiversity and ecological processes.

Precipitation seasonality and soil pH drive the large-scale distribution of soil invertebrate communities in agricultural ecosystems.

Soil invertebrates contribute significantly to vital ecosystem functions such as the breakdown of organic matter and cycling of essential nutrients, but our knowledge of their large-scale distribution in agricultural systems is limited, which hinders our ability to robustly predict how they will respond to future global change scenarios. Here, we employed metabarcoding analysis of eukaryotic 18S rRNA genes to examine the diversity and community composition of invertebrates in 528 sorghum rhizosphere and bulk soils, collected from 53 experimental field sites across China. Our results revealed that Nematoda, Arthropoda, and Annelida were the dominant soil invertebrate groups in agroecosystems. Among all climatic and soil parameters we examined, precipitation seasonality (i.e. the irregular distribution of precipitation during a normal year) had the strongest relationship with the richness of soil invertebrates, with an increase in soil invertebrate richness predicted with increasing precipitation seasonality. Mean annual precipitation and soil pH were the most important predictors of soil invertebrate community structure, with numerous invertebrate phylotypes showing either significantly positive or negative relationships with these two variables. Our findings suggest that shifts in precipitation patterns and soil pH, induced by future climate change and agricultural practices, will have important consequences for the distribution of soil invertebrate communities, with implications for agricultural ecosystem sustainability.

Multi-Scale Altitudinal Patterns of Soil and Litter Invertebrate Communities in a Warm Temperate Deciduous Broadleaf Forest

The diversity and spatial patterns of soil invertebrates are the cornerstones for understanding their ecological functions, which are crucial to maintaining nutrient cycling and soil health in forest ecosystems. Based on a continuous altitudinal gradient (1020–1770 m) composed of 119 plots, this study analyzed the spatial patterns of invertebrate communities in temperate mountain forest litter and soil using multi-scale ordination. The results indicate that along the altitudinal gradient, the invertebrate communities in both litter and soil layers exhibit “patches” at a scale of approximately 33 plots that are mainly composed of Mesostigmata and Apterogasterine oribatid mites. In the litter layer, at the 11-plot scale, an aggregation of Onychiuridae is also formed, while in the soil layer, there are “patches” represented by Diadocidiidae at the 33-plot scale. The positive–negative associations among invertebrate taxa also shift between the litter and soil layers, as well as among “patches”. Our study confirms that the richness of invertebrates in temperate-forest litter is higher and forms multi-scale assembly “patches” despite the higher abundance of invertebrates in the soil layer. Future studies should delve deeper into the aggregation mechanisms of these specific taxa and may require higher sampling densities to reveal the multi-scale spatial patterns of soil invertebrates.

Altitudinal patterns of dominant invertebrates in forest soil and litter are scale-different

Soil invertebrates directly and indirectly contribute to soil formation and development, nutrient cycling, and other ecological processes and are important biological components of terrestrial ecosystems. However, regardless of the large differences in the physicochemical properties between soil and litter, the conditions in which soil- and litter-dwelling invertebrates exhibit similar spatial patterns along the same altitudinal gradient are not clear. In this study, we investigated invertebrates in forest soil and litter layers along an altitudinal gradient (1020–1770m a.s.l.). We used multivariate wavelet analysis to compare the altitudinal patterns of 14 dominant soil and litter-dwelling invertebrates and identified the most relevant factors of these patterns using a Random Forest. The spatial patterns of soil- and litter-dwelling invertebrates differed significantly at 76 m and 206 m scales. The dominant taxa exhibited similar altitudinal patterns at the 76 m and 206 m scales in the litter layer, although they differed at approximately 6 m scale. Moreover, resource diversity (herb richness for litter and tree richness for soil layer) was the main factor affecting the differences in spatial patterns between soil- and litter-dwelling invertebrates at 76 m scale, whereas soil heterogeneity (sand percentage for litter layer and temperature for soil) at the 206 m scale. Our results suggest that the responses of soil- and litter-dwelling invertebrates in forests are not always similar across the same altitudinal gradient and whether they need to be separated depends on their analytical scales. Meanwhile, the factors most related to the pattern differences between the two layers varied with scale. This study emphasises the need to conduct separate investigations and modelling simulations for the litter and soil layers to comprehensively assess soil invertebrate diversity across scales, which will provide valuable insights into the intricate mechanisms underlying the spatial-temporal dynamics of soil invertebrate communities.

Rocks, lichens, and woody litter influenced the soil invertebrate density in upland tundra heath.

Soil invertebrates are an integral part of Arctic ecosystems through their roles in the breakdown of litter, soil formation, and nutrient cycling. However, studies examining soil invertebrates in the Arctic are limited and our understanding of the abiotic and biotic drivers of these invertebrate communities remains understudied. We examined differences in soil invertebrate taxa (mites, collembolans, enchytraeids) among several undisturbed upland tundra heath sites in Nunavut Canada and identified the drivers (vegetation and substrate cover, soil nutrients and pH) of the soil invertebrate community across these sites. Soil invertebrate densities were similar to that of other Arctic studies. While invertebrate communities were relatively consistent between our sites, cover of rocks, woody litter, and the lichen Alectoria nigricans had significant, positive influences on the density of all invertebrates studied. Mites and collembolans were more closely associated with cover of lichens, whereas enchytraeids were more closely associated with woody litter and rocks. Our results suggest that anthropogenic (e.g., resource exploration and extraction) and/or natural (e.g., climate change) disturbances that result in changes to the vegetation community and woody litter inputs will likely impact soil invertebrates and the ecosystem services they provide.

Impact of No-Tillage on Soil Invertebrate Communities in the Southern Forest Steppe of West Siberia: Preliminary Research

The aim of our study is to assess changes in soil macroinvertebrate biodiversity when conventional tillage (CT) is replaced by no-tillage (NT) in agroecosystems of the southern part of the West Siberian forest steppe. The research was conducted in the Novosibirsk region at the end of May 2017, May 2018, and in June 2018. The agricultural plots with CT and NT were located close to each other on identical soils, at a distance of about 200 m from the nearest forest shelterbelts. NT technology has been applied on the experimental plot since 2007. Sampling of invertebrates was conducted in two ways, namely soil sampling and pitfall trapping. The majority of basic physicochemical properties of soil were the same or similar between the CT and NT plots. However, depending on the type of tillage, different soil invertebrate communities had already developed in the control (CT) and experimental (NT) plots during this time. The community of the CT plot includes a large number of flying predatory Carabidae species typical of early successional stages (such as Bembidion properans and B. quadrimaculatum, Poecilus spp.) and phytophages, i.e., larvae of Elateridae. The NT plot has significantly higher density and species richness of earthworms (Eisenia nordenskioldi and synanthropic E. fetida in the NT plot versus one individual of E. nordenskioldi in the CT plot). The NT plot has a significantly richer and more abundant assemblage of spiders (especially in spring) and a poor assemblage of insect predators (except for the superdominant ground beetle Poecilus cupreus and the subdominant P. versicolor in summer 2018). Large numbers of larvae of some carabids (e.g., Amara consularis) were found in the NT soil, suggesting that they complete a full life cycle in this habitat.

A Multi-Community Approach in Biodiversity Assessment of a Peat Bog in the Southern Carpathians (Romania) and Implications for Conservation.

Although natural peatlands have been recognized as an important type of wetlands because they support high biodiversity and provide important ecosystem services, the value of peatlands both in biodiversity research and conservation is still largely underestimated. Our study characterizes the biodiversity and conservation value of Peşteana peat bog, an upland mesotrophic peat bog, located in the Southern Carpathians, Romania. More specifically, we: (1) characterized the invertebrate (i.e., top soil, surface litter, and plant-dwelling) and plant communities along a humidity gradient in Peşteana peat bog and nearby habitats (i.e., treeline, ecotone, lowland and highland meadow, and forest), (2) assessed the main environmental factors driving the invertebrate community diversity and composition, and (3) determined the relationship between invertebrate community diversity and vegetation, focusing on the top soil invertebrates. Our study revealed a high diversity of invertebrates spanning over 43 taxonomic groups and a high number of plant indicator species, emphasizing the role of natural peatlands in preserving diverse communities in a small area. The results showed that the composition of top soil invertebrate community was determined by depth of organic layer, vegetation cover, and soil compaction. We found that the diversity of top soil invertebrate community was strongly influenced by habitat type and soil attributes and weakly by vegetation. Overall, the invertebrate and plant communities showed different responses to habitat conditions along the humidity gradient. This highlights the importance of using a multi-community approach to support the design of effective conservation and management actions beneficial for a wide range of taxa.

Native forest conversion alters soil macroinvertebrate diversity and soil quality in tropical mountain landscapes of northern Ecuador

Land use changes cause soil degradation and loss of biodiversity, thereby affecting ecological processes and soil-associated ecosystem services. However, land use change impacts on soil health have received little attention in the highland landscapes of the tropics. In this research, using the soil health framework, we assessed the impact of native forest conversion to anthropic systems (planted forests, pastures, and monocultures) on two ecosystem services: biodiversity conservation and soil fertility in the highlands of northern Ecuador. The biological dimension of our assessment focused on the diversity, abundance, and biomass of soil macroinvertebrate communities as proxies to soil functions, whereas soil chemical parameters were used to describe the soil fertility. The soil invertebrate communities and soil chemical parameters were studied in topsoil samples using 25 × 25 × 10 cm monoliths, obtained from 10 sampling sites randomly selected in each land use category. We hypothesized that native forests would present more diverse and even soil macroinvertebrate communities, and together with their soil chemical properties would indicate better soil quality than anthropic environments. Our results showed that the structure and composition of the edaphic macroinvertebrate communities significantly differed among the studied land use categories. As predicted, native forests presented greater values for richness, evenness and diversity of soil biota than did the other categories, demonstrating a significant loss of taxonomic biodiversity at order and genus levels. We also found a significant reduction of trophic diversity in native forests converted to anthropic environments. More trophic groups with greater abundances were found in native forests, where predators and detritivores stood out as dominant groups, indicating the good quality of the soil. The results from the soil chemical parameters also confirmed the distinction in soil health between native forests and anthropic environments. Our results highlight the risk associated with current trends of native forest loss and conversion to anthropic systems in high mountain ecosystems in the tropics, illustrating how these alterations could cause biodiversity loss and degradation of the chemical attributes of soil health. The findings of this research could contribute to the conservation and sustainable management of mountain agricultural landscapes in the study region.

Soil faunal communities in mass outbreak areas of the great web-spinning sawfly Acantholyda posticalis (Mats.) are impoverished compared to pest-free Scots pine forests

Mass outbreaks of pests defoliating Scots pine monocultures are of constant concern to foresters, and the increase in their frequency under conditions of a warming climate is expected. Repeated mass outbreaks usually involve the same areas, which suggests that predispositions to pest attack are shaped by certain stand characteristics or their habitat conditions. The aim of the study was to examine whether the soil invertebrate communities of pine forests with A. posticalis mass outbreaks differ from those of stands with no mass occurrence of this pest, despite analogous stand-habitat conditions and close proximity. Pine monocultures in two regions of Poland differing in the timing of the pest's mass occurrence were selected for the study. The soils of the studied monocultures, both in outbreak areas and reference tree stands, were characterized by strong acidity and low nutrient status. A lower (soil invertebrate communities) and a higher (Collembola communities) taxonomic resolution were used to assess the differences between the soil fauna of infected and reference stands. We show that soil invertebrate communities of the mass outbreak areas were characterized by impoverishment compared to those of reference forests. However, both invertebrate and Collembola communities, which in outbreak areas consisted of fewer taxa, did not differ significantly in density from reference tree stands. Nonmetric multidimensional scaling (NMDS) ordination of the collembolan communities revealed that not only their composition but also their structure in the mass outbreak areas differed significantly from those of uninfected tree stands. Further research is needed to clarify whether the depletion of soil invertebrates is a result of foliar insect feeding, or is rather a manifestation of weakened stands increasing their predisposition to attacks by pest insects.

Soil Invertebrate Communities as Indicator of Ecological Conservation Status of Some Fertilised Grasslands from Romania

Quantification of soil biological status, through investigation of edaphic communities’ composition, constitutes an important factor for the assessment of the grassland ecosystems, including their protection. The structure of soil invertebrate communities was investigated for five grasslands under different chemical and organic treatments, for the first time in Romania. In order to accomplish this task, some structural parameters were quantified: numerical abundance, taxa richness, Shannon diversity index of taxa and equitability. We demonstrated the relationship between five environmental factors (vegetation coverage, soil temperature, soil acidity, soil resistance at penetration, soil moisture content) and the community structures of soil fauna. In total, 17 invertebrate groups were identified with a total numerical abundance of 14,953 individuals. Considering the numerical abundance, the dominant taxa were Acaridae, Collembola, Oribatida and Mesostigmata, the least dominant being Coleoptera, Opiliones and Araneae. In spatial dynamics the investigated plots were characterised specifically by soil invertebrates’ communities’ structures, highlighted by the varied values of structural parameters: by indicator taxa and by the characteristic average values of environmental parameters. Multivariate statistical analysis revealed that the most important environment parameters influencing the soil taxa were vegetation coverage (especially on Acaridae, Glycyphagidae and Formicoidea) and soil resistance at penetration (Nematoda and Coleoptera). This study constitutes a scientific argument for the usage of soil invertebrate communities as indicators of the ecological conservation status of some fertilised grasslands.