Earthworm Abundance Research Articles

Influence of anthropogenic factors and soil properties on earthworm diversity in southern Mediterranean agroecosystems

This study examines the biodiversity of earthworms in agroecosystems in the Annaba region of northeastern Algeria, focusing on the impact of agricultural practices and soil environmental conditions on these species. Seven earthworm species from the Lumbricidae and Megascolecidae families have been identified, of which five are new records for this region. Areas with intensive human activity exhibited a decrease in earthworm abundance and diversity, whereas areas with less intensive agricultural practices showed higher levels of earthworm diversity. Variations in soil properties related to land use and plant diversity were notable. Intensive agricultural practices resulted in altered soil characteristics, such as higher pH, electrical conductivity (EC), and salinity, while organic amendments increased organic carbon and nutritional diversity. Essential nutrients, such as calcium and magnesium, are crucial for earthworm vitality, while high levels of pH, salinity, and EC can reduce their populations. Canonical Correspondence Analysis supports these findings. In summary, agricultural practices and soil environmental conditions significantly influence earthworm populations, underscoring the need for sustainable methods to preserve underground biodiversity and ecosystem services.

Resilience underground: Understanding earthworm biomass responses to land use changes in the tropics

Soil biodiversity, like terrestrial biodiversity, is currently under threat by changes in land use. Intensively managed farming activities with agrochemicals have degraded both soil biodiversity and health. However, little is known about how these changes in land use affect the distribution of earthworm biomass in Southeast Asia. We conducted earthworm sampling across multiple habitats, including lowland forests, exotic monoculture plantations (e.g., oil palm and rubber tree), and agroforestry orchards. To survey earthworm populations, we excavated the top 30 cm of soil at 18 sites encompassing 399 plots distributed across natural and human-modified ecosystems in Selangor and Negeri Sembilan, Peninsular Malaysia. We found that earthworm abundance was negatively related to increasing soil compaction, leaf litter weight, soil pH, and undergrowth height, whereas it was positively associated with increasing undergrowth and canopy cover. Our findings demonstrated that agroforestry orchards, rubber tree plantations, and mature oil palm plantations had higher earthworm abundance than those in logged lowland forests. Earthworm abundance in unlogged lowland forests and young oil palm plantations, on the other hand, was lower than in logged lowland forests. Overall earthworm weight was greater in rubber tree plantations, agroforestry orchards, mature oil palm plantations, and unlogged lowland forests than those in logged lowland forests, while young oil palm plantations exhibited lower earthworm weight than logged lowland forests. Our data indicate that increases in soil compaction and leaf litter weight were associated with decreased earthworm weight. These results demonstrate the importance of site-level habitat management for maintaining healthy earthworm populations and soil biodiversity.

Let the dust settle: Impact of enhanced rock weathering on soil biological, physical, and geochemical fertility

Terrestrial enhanced rock weathering (ERW) is a promising carbon dioxide removal technology that consists in applying ground silicate rock such as basalt on agricultural soils. On top of carbon sequestration, ERW has the potential to raise the soil pH and release nutrients, thereby improving soil fertility. Despite these possible co-benefits, concerns such as heavy metal pollution or soil structure damage have also been raised. To our knowledge, these contrasted potential effects of ERW on soil fertility have not yet been simultaneously investigated. This field trial aimed at assessing the impact of ERW on biological, physical, and chemical soil properties in a temperate agricultural context. To do so, three vineyard fields in Switzerland were selected for their distinct geochemical properties and were amended with basaltic rock powder at a dose of 20 tons per hectare (2 kg.m−2). On each field, basaltic rock powder was either applied one year before the sampling campaign, one month before the sampling campaign, or not applied (control) for a total of 27 plots with 9 repetitions of each level. Overall, basaltic rock powder addition had a predominantly positive to neutral effect on soil fertility. Most soil properties showed no significant change either 1 month or 1 year post application. Nevertheless, our study highlighted a significant increase in earthworm abundance (+71 % on average), soil respiration (+50 %) and extractable sodium concentration (+23 %) as early as 1 month post application. The higher soil respiration raises the question of CO2 losses from organic matter mineralization that could limit ERW's efficiency. The increase in sodium raises concerns about a sodification risk potentially damaging soil fertility. These elements now require further investigation before enhanced rock weathering can be considered a viable and secure carbon dioxide removal technology.

Grasslands support more diverse and resilient earthworm communities to climate change than croplands in Central Europe

Diversity and community composition of earthworms, key drivers of ecosystem functions, are increasingly threatened by global change, including climate and land-use change. However, empirical evidence for interactions of these concurrent drivers in affecting earthworm communities is scarce. Here, we investigated the effects of an experimentally imposed climate change scenario, including warming and altered precipitation patterns, and land use with two croplands (both conventional farming and organic farming characterize a three-year crop rotation) and two grasslands (intensively-used meadow and extensively-used meadow) on earthworm communities across different seasons and years in a field experiment. Compared with grasslands, earthworms in croplands have lower species richness (-26 %), abundance (-80 %), and biomass (-73 %), particularly the abundance of juveniles (-83 %) and Aporrectodea rosea (-76 %) as well as the biomass of juveniles (-84 %), A. rosea (-72 %), Octolasion cyaneum (-47 %), and Lumbricus terrestris (-83 %). Due to extreme droughts in Central Europe from 2018 to 2020, earthworm abundance and biomass were low across land-use types, but in grassland they increased (abundance: +80 %; biomass: +85 %) in 2021 presumably due to increased moisture conditions. Main effects of experimental climate change and intensified management practices as well as interaction of experimental climate change and land use on abundance and biomass of earthworms were non-significant. Notably, experimental climate change and land use interactively altered earthworm community composition, with the most pronounced difference between ambient and future climate in croplands than in grasslands. This indicates that earthworm community composition more sensitively reflects changes in environmental conditions than earthworm abundance and biomass, but the latter two negatively responded to prolonged drought conditions. Our results indicate that grasslands have a higher resilience of earthworm populations to buffer adverse environmental conditions than croplands. Overall, this study provides a comprehensive overview of the response of earthworms to inter-annual climatic variability and experimental climate change under different land-use types.

The effects of agricultural practices on earthworm communities in Estonia

Earthworms support and mediate the provision of many processes in the soil. They are therefore important in maintaining soil functioning and contribute towards the sustainability of soil management systems. Assessment of earthworm communities can provide answers regarding the land management conservation efforts and insight on soil quality. The main aim of this study was to assess the impact of farming (organic vs conventional) and tillage (no-tillage vs minimum tillage vs conventional tillage) systems on earthworm communities under varying soil conditions in arable fields across Estonia. To achieve this, we compiled data from studies carried out over a period of 21 years on Estonian arable fields. While organic farming and conventional farming showed a similar earthworm abundance, earthworm diversity was significantly higher (p < 0.05) under the organic system. Higher abundance, species richness, and the proportion of anecic species suggest that a no-tillage system creates the most favourable habitat conditions for earthworms. Soil texture further influenced the effect of management system on earthworm abundance and diversity indexes. For example, the differences in earthworm abundance and diversity between the management systems increased from lighter textured to heavier textured soils. Our results suggest that soil texture is a major factor influencing earthworm communities in Estonian agricultural fields and emphasizes the importance of including different soil texture classes when assessing the effects of agricultural management practices in field-scale studies.

Grasslands and flood mitigation – Contrasting forages improve surface water infiltration rates

Grasslands globally deliver many ecosystem services, including water management to alleviate flood risk reduction. Two replicated field experiments were conducted to study how agricultural forage species with diverse rooting systems, sown as single species, affected rooting, soil structure and earthworm populations, and consequently water infiltration to understand how they each might influence flood risk from grasslands. Experiment One showed soils under red clover (Trifolium pratense), white clover (Trifolium repens) and chicory (Cichorium intybus) had higher infiltration rates three years after establishment, compared to perennial ryegrass (Lolium perenne). Higher red clover and chicory root biomass or increased earthworm abundance under white clover may have caused these effects. Experiment Two monitored infiltration at intervals over several years post establishment to understand the timeframe for changes in rates; plantain (Plantago lanceolata) was sown as an additional forage. Infiltration declined post establishment, the timing and extent of decline varying with forages; forage effects were significant after 27 months (P < 0.05). Infiltration rates were higher under red and white clover compared to ryegrass, with chicory and plantain intermediate (P < 0.05). Forages again differed in likely mechanisms delivering higher water infiltration, notably between the two clover species. White clover had higher earthworm biomass (P < 0.05), whereas red clover had a higher average root diameter compared to the other forages (P < 0.05). Drivers of intermediate benefits of chicory and plantain also differed: chicory had higher earthworm abundance (month 38) compared to plantain, which had higher average root diameter compared to ryegrass (month 41); 30 months post-establishment soil bulk density was lower under both forages compared to ryegrass and red clover, with white clover intermediate (P < 0.05); bulk density and penetration resistance did not relate to infiltration. Findings demonstrate that a shift from perennial ryegrass-dominated pastures to swards with more contrasting forages provides an ecohydrological approach to mitigating flood risk and climate adaptation.

The effect of soil parameters and earthworm abundance on the fine-scale nocturnal habitat use of the Eurasian woodcock (Scolopax rusticola).

The Eurasian woodcock prefers habitats where its main prey, earthworms, can be found in higher densities. Although they are forest-dwelling birds, they regularly visit pastures and natural grasslands at night, where earthworm abundance is generally higher. However, there is little information on fine-scale habitat use in relation to variation in habitat characteristics and prey availability, particularly beyond the breeding season. In our study, we investigated if the nocturnal occurrence of woodcocks during migratory stopover periods differed between two neighbouring fields, or management units, with similar vegetation structure, and if within-field variation in the spatial patterns of woodcock sightings were associated with fine-scale earthworm densities and soil parameters. Specifically, we used GPS tracking data of two tagged woodcocks and direct observation data to study patterns of occurrence of birds in a mixed forest-pasture landscape in Hungary during pre- and post-breeding periods. We compared these patterns with fine-scale soil characteristics and earthworm abundance, acquired by field sampling. We found that the field with higher earthworm abundance was visited by woodcocks more frequently, and this correlation was similarly observed at the intra-field level. Our results demonstrate that woodcocks select foraging sites with higher earthworm densities at multiple spatial scales, both between fields (coarse scale), and within fields (fine-scale). Considering that woodcocks tended to return to the same field to forage at night, the strong associations between occupancy and resources provide a basis for developing habitat management strategies at the field level for conservation. As earthworm densities and soil parameters are good indicators of woodcock foraging habitat, measuring those variables, at least at a coarse scale, could aid in predicting important habitats for the species across the landscape.

Challenges in viticulture practices in a changing environment: Can green waste amendment benefit soil properties of vineyards in the Mediterranean?

In Southeastern France, viticulture is of great social, cultural, and economic importance. This sector is threatened by climate change particularly in the Mediterranean (longer droughts and more frequent heat waves) where soils are poor in organic matter and weakly developed. Since organic amendment can strongly modify soil properties and consequently the final products (grapes and wine), the effects of sustainable practices on soil characteristics have to be carefully assessed. This seasonal field survey focuses on the effects green waste amendment (GWA), i.e. semi-composted green wastes, have on vineyard soil functionality. The effects of GWA were compared with those of grass cover (GC), known as a sustainable practice. Soils were collected in vineyards under organic practices (Bouches-du-Rhône and Var, France) over four seasons and physico-chemical (Total C and N, pHwater, pHKCL, EC, WHC, copper content and soil organic carbon SOC) and biological (microbial respiration and biomass, microbial catabolic structure, earthworm abundance and biomass) properties were characterized. Both practices were beneficial to soil physicochemical properties. For example, under both practices, higher (2 fold) Total N and SOC on late spring were observed. Both GWA and GC favored soil microbial communities, with microbial respiration having doubled and tripled on late spring. Similar results were observed for microbial biomass and both bacterial and fungal catabolic diversities (increased approximately by half) over summer. These benefits were particularly prominent during drought season (June and August), and probably linked to a shift in microbial communities as revealed by catabolic profiles. GWA also favored abundance and biomass of earthworm during winter. These findings reveal the potential GWA to counteract the effect of tillage, to mitigate the stress from drought and to improve overall soil functionality in vineyards.

Forecasting Oligochaeta Abundance using the Apparent Electrical Conductivity of Irrigated Soils with Reclaimed Wastewater: Evidence from Corso, Algeria

Background: The main objective of this paper is to study the possibility of using the measurement of apparent electrical conductivity (ECa) to estimate Oligochaeta (earthworm) density in irrigated soils treated with reclaimed wastewater. Additionally, the study sought to analyze the impact of using reclaimed wastewater for irrigation on earthworm density in the study area. Methods: Earthworm sampling was carried out at thirty emplacements within the study area during two measurement campaigns. Soil ECa was measured by (EM38). Result: The results showed that irrigation with reclaimed wastewater promotes the abundance of earthworms (earthworm density). Indeed, sites irrigated with reclaimed wastewater have higher earthworm densities compared to sites irrigated with conventional water. The results also show a strong correlation between ECa and earthworm density (R2 greater than 0.7). The Wilcoxon test indicates a non-significant difference between measured earthworm densities and those predicted by ECa (p greater than 0.5). This result confirms the effectiveness of the EMI technique as a tool to evaluate the spatial variability of soil biological parameters. These results collectively suggest that ECa represents a real possibility of reducing the number of earthworm samplings, whil ensuring the reliability of the estimates of real values of earthworm density and their surface spatial distribution. ECa could therefore be a useful tool to spatialize and predict the presence of earthworms in soil irrigated by reclaimed wastewater.

Permaculture enhances carbon stocks, soil quality and biodiversity in Central Europe

Permaculture is proposed as a tool to design and manage agroecological systems in response to the pressing environmental challenges of soil degradation, climate change and biodiversity loss. However, scientific evidence on the effects of permaculture is still scarce. In this comprehensive study on a wide range of soil and biodiversity indicators, we examined nine farms utilizing permaculture and paired control fields with locally predominant agriculture in Central Europe. We found 27% higher soil carbon stocks on permaculture sites than on control fields, while soil bulk density was 20% lower and earthworm abundance was 201% higher. Moreover, concentrations of various soil macro- and micronutrients were higher on permaculture sites indicating better conditions for crop production. Species richness of vascular plants, earthworms and birds was 457%, 77% and 197% higher on permaculture sites, respectively. Our results suggest permaculture as effective tool for the redesign of farming systems towards environmental sustainability.

Wildflower strips of 2.5-year-old promote earthworms and enchytraeids (Annelida, Oligochaeta) in arable fields

In the last 50 years, humans have increased crop yields due to intensive agricultural practices and by homogenizing cultivated lands (e.g., larger and more uniform fields). However, this land management practice has led to serious environmental issues, and now, the importance of heterogeneity and semi-natural landscape elements in production systems is acknowledged. Perennial habitats, such as flower strips, could play a key role in agroecosystem sustainability, but little is known about their effects on earthworm and enchytraeid (Annelida: Oligochaeta) communities. The aim of this study was to assess earthworms and enchytraeids in 2.5-year-old wildflower strips that were sown in the middle of arable fields in northern France. Samples (soil, earthworms and enchytraeids) were collected at ten locations, in flower strips and in adjacent cropped fields. The same number of earthworm species was found in both habitats, but more enchytraeid species were detected in the flower strips than in the adjacent cropped fields. Moreover, the total abundance of earthworms and enchytraeids significantly increased in the flower strips compared with the adjacent cropped fields, by 69 % and 61 %, respectively. Flower strips had a significant positive effect on anecic and endogeic earthworms but not on the abundance of epigeic earthworms, which was highly variable among the samples, although on average, it was seven times greater in the flower strips than in the cropped fields. Although the flower strips were sown only 2.5 years earlier, significant changes were observed in the soil Oligochaeta communities. These findings advocate for sowing flower strips within cultivated land as a source of soil biodiversity in the current changing environment. Considering the positive role of flower strips on biodiversity and particularly on the studied tiny soil engineers, these perennial landscape elements should be more widely considered to support the agroecological transition.

Potential of conservation tillage, cover crops, and digestate application as integrated C farming practices for processing tomato

Conventional soil management — based on intensive tillage and low input of organic material – negatively impacts soil quality via carbon (C) losses as carbon dioxide emissions (CO2), exacerbating the effect of climate change on agriculture. Carbon farming practices (CFPs), such as minimum tillage (MT) and strip tillage (ST), offer promising solutions to maintain soil fertility, sustain crop yields, and mitigate environmental impacts. However, applying CFPs in processing tomato (Solanum lycopersicum L.) cropping presents unique challenges due to specific crop and tillage characteristics. Our two-year field study investigated the effects of conservation tillage practices (i.e., MT and ST), both combined with cover crops and digestate application, on soil quality parameters and processing tomato yield. The field studies were conducted in fields with varying soil textures (i.e., clay and silty clay loam), and aimed to evaluate responses in terms of soil C sequestration, nutrient concentrations, soil structure, and abundance of earthworms. We hypothesized that both MT and ST would enhance soil quality parameters also in tomato cropping systems, with ST potentially outperforming MT in C sequestration. Results revealed that CFPs significantly increased soil organic matter, total nitrogen, and available phosphorous compared with conventional tillage. Both MT and ST increased soil C sequestration (up to 1.06 Mg C ha−1 y−1 and 1.21 Mg C ha−1 y−1, respectively) compared with conventional tillage (CT), which lost around 0.88 Mg C ha−1 y−1 under silty-clay loam soil, and had negligible C sequestration (+0.02 Mg C ha−1 y−1) under clay soil. We found no significant difference between MT and ST when using the equivalent soil mass method for calculating C sequestration. Noteworthy, CFPs enhanced fertility parameters without a negative impact on yields, underscoring their potential for enhancing soil C sequestration, improving nutrient availability, and supporting processing tomato yield under adaptation scenarios to climate change.

Effects of reduced tillage and prolonged cover cropping in maize on soil quality and yield

Maize (Zea mays L.) is the most common arable crop on sandy soils in the Netherlands, and it is often grown for several consecutive years after temporary grassland. For the maize-growing years, reduced tillage intensity and prolonged growing period of cover crops could limit declines in soil organic matter (SOM) and soil biota while maintaining soil structure and maize yield. We measured soil parameters and maize yield in an eight-years field experiment on sandy Gleyic Podzol. Treatments included four cropping systems differing in tillage intensity but with conventional sowing dates (conventional inversion tillage (CT), non-inversion tillage (NIT), strip tillage (ST) and no-till (NT)), and two cropping systems (CT-prolonged and ST-prolonged) with prolonged growing period of a winter rye-winter pea cover crop combined with a late sown short-season maize (18 weeks growth). After eight years, we found no evidence for differences in SOM or total carbon content between the treatments. However, in the reduced-tillage treatments, SOM content was higher in the top (0–15 cm) than in the bottom (15–30 cm) of the plough layer, while in CT and CT-prolonged, this stratification was inverted. We observed differences in earthworm abundance, biomass and functional group distribution. In comparison to CT (100 %), the earthworm abundance was 153 % in NIT, 235 % in ST and 206 % in NT whereas earthworm biomass was 269 % in NIT, 325 % in ST and 475 % in NT. Epigeic earthworms were more affected by tillage than endogeic earthworms. Compared to CT, earthworm biomass was higher in CT-prolonged. The initially low earthworm population recovered during the course of the experiment independent of tillage intensity.Higher soil penetration resistance was observed in the reduced tillage systems compared to CT, independent of prolonging the cover crop. Despite the increased penetration resistance, the maize yields in NIT and ST were similar to CT. The maize yields were lower in NT, CT-prolonged and ST-prolonged compared to CT, but no differences were observed between CT-prolonged and ST-prolonged. The biomass of the harvested prolonged cover crop closed the yield gap in relation to CT in four out of six years in which cover crop biomass in CT-prolonged and ST-prolonged was quantified. Based on our results, we recommend strip tillage for continuous maize-cropping systems on Dutch sandy soils. In the case of severe compacting of compaction prone soils, we recommend conventional tillage with a prolonged cover crop and short-season maize variety.

Investigating soil health and resilience in small-scale agroecosystems of Mount-Lebanon

ABSTRACT In response to Lebanon’s 2019 economic crisis, agricultural activities intensified to enhance national food security, with implications for soil health. We investigated soil management practices on 26 small-scale farms in a mountainous region, focusing on reconciling static sustainability definitions with dynamic resilience concepts. Surveying farmers revealed varied adoption rates of regenerative practices: intercropping (85%), residue retention (73%), cover crops (61%), organic amendments (46%), integrated organic/mineral amendments (46%), improved irrigation (38%), conservation tillage (30%), crop rotation (19%), and organic/biological pest/disease treatment (11%). Farms were categorized as conventional (C), neutral (N), and regenerative (R) based on practices. Qualitative assessments using seven indicators yielded scores of 4.28 (C), 6.34 (N), and 7.88 (R). Quantitative analyses showed significant differences in soil organic matter percentage (1.86 C, 2.75 N, 3.32 R), soil respiration (156 C, 296 N, 380 R), and earthworm abundance (2.92 C, 4.24 N, 5.72 R). The Soil Quality Index (SQI) indicated varying soil health from 0.05 (C) to 0.49 (R). Our findings highlight the importance of adopting synergistic, sustainable soil management practices to ensure enduring agricultural productivity and safeguard soil resilience, especially in the Mediterranean region.

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 &gt; DG; abundance by 24% (p &lt; 0.05), biomass by 22% (p &lt; 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.

Maintaining favourable carbon balance in boreal clay soil is challenging even under no-till and crop diversification

We explored the carbon balance, including both gaseous and waterborne carbon, of a long-term experimental site in 2019 and 2020. Additionally, we assessed earthworm abundance and soil aggregation, aiming to uncover potential factors influencing the decomposition and stabilization capacity of organic carbon in the soil. The heavy clay soil site in southern Finland was under long-term cereal monocropping with conventional tillage (CT) and no-till (NT) treatments. Short-term diversification with cover crop and winter rapeseed as a break crop were applied on parts of the site, and the effects of climate, carbon input and soil conditions on the carbon balance were assessed. Net ecosystem exchange (NEE) ranged from −0.32 to 1.91 Mg CO2-C ha−1 yr−1 in CT and from 0.22 to 2.40 Mg CO2-C ha−1 yr−1 in NT. Net ecosystem carbon balance ranged from 1.49 to 3.27 Mg C ha−1 yr−1 and 1.51 to 3.67 Mg C ha−1 yr−1 in CT and NT, respectively, indicating carbon loss from soil. The differences in NEE or carbon balance between CT and NT were not statistically discernible. Earthworm abundance was higher in NT than in CT and increased vastly in the NT management after diversification of the rotation with winter rapeseed. Soil erosion measurements showed remarkably lower carbon loss (44%) for NT compared to CT, however, the role of erosion in the carbon balance was minor, ranging from 50 to 120 kg C ha−1 yr−1. The mean size of soil aggregates decreased during the study period, and soil aggregates tended to enlarge in the summer and diminish in the winter. The results highlight the difficulty of maintaining a positive carbon balance in boreal agricultural soils with limited productivity. Furthermore, future climatic conditions may worsen the situation by promoting decomposition and restricting carbon protection in soil aggregates.

Soil and Vegetation Characteristics of Grassland have a Greater Influence on the Abundance and Diversity of Earthworms than the Mowing Intensity in a Managed Nature Reserve

Effects of mowing on vegetation parameters have been well studied. However, less is known about mowing effects on soil fauna and if soil properties alter this. We investigated earthworm communities in a long-term experiment 14 years after its establishment in 5 dry, fresh and moist grassland plots located in the Natura 2000 site Lainzer Tiergarten near Vienna, Austria (238–402 m a.s.l., 48°10′ N, 16°12′ E). The grasslands were either mowed once a year or every second year, or not mowed since being established. Earthworms were assessed using the non-destructive octet electro-shocking method. Additionally, vegetation composition, soil conductivity, temperature and moisture were assessed. We found 13 earthworm species across all treatments, although their abundance was generally low with 6.1 ± 4.7 worms m−2. The total earthworm abundance and species diversity was higher in dry compared to fresh and moist grasslands but was not affected by mowing frequency. Endogeic earthworms (Aporrectodea caliginosa, Aporrectodea rosea) and epigeics (Lumbricus rubellus) were more tolerant to mowing than anecics (Lumbricus terrestris, Allolobophora longa). Since plant species richness was highest in annually mown grasslands and earthworm species richness was positively related to plant species numbers, we recommend regular, low-input management to promote above- and belowground biodiversity in these grasslands.

Assessing dietary specialization to inform the conservation of the fairy pitta (Pitta nympha), an endangered vermivore.

Quantifying the diet of endangered species is crucial for conservation, especially for diet specialists, which can be more susceptible to environmental changes. The vulnerable fairy pitta (Pitta nympha) is considered a specialist that primarily feeds its nestlings with earthworms. However, there have been few studies of the nestling diet provisioned by parents, and no assessments of earthworm proportion in the diet of adults. Our study aimed to fill these gaps, shedding light on crucial factors for conservation. Combining new observations with existing literature, we confirmed a consistent dominance of earthworms in the nestling diet, regardless of rainfall, nestling age, and time of day. We extrapolated the total earthworm consumption during a breeding event, accounting for potential variation in the availability of earthworms and their prevalence in the adult diet. We used literature-based earthworm densities in pitta habitats and our estimates of family earthworm consumption to calculate the habitat area that could provide a pitta family with the number of earthworms consumed during a breeding event. The predictions matched observed pitta home range sizes when assumed that the adult diet is comprised of approximately 70% earthworms. The results highlight the importance of earthworm-rich habitats for conservation planning of the fairy pitta. To mitigate the effects of habitat destruction, we discuss conservation practices that may involve enhancing earthworm abundance in natural habitats and providing vegetation cover for foraging pittas in adjacent anthropogenic habitats rich in earthworms. To guide conservation efforts effectively, future studies should investigate whether previously reported breeding in developed plantation habitats is due to high earthworm abundance there. Future studies should also quantify correlations between local earthworm densities, home range size, and the breeding success of the fairy pitta.

Earthworm Watch: Insights into urban earthworm communities in the UK using citizen science

The distribution of earthworm ecological groups in urban areas is not well-known, despite their crucial role in delivering soil ecosystem services such as nutrient cycling and water drainage. Citizen science engages public audiences in the scientific research process and is an excellent tool for collecting biodiversity data in urban areas, where most of the UK population resides. However, a disadvantage is that differing levels of skill and engagement among participants can create statistical challenges. The Earthworm Watch citizen science project used 668 matched-pair surveys to estimate how the abundance and ecological diversity of earthworms respond to land management practices, and soil properties in UK urban habitats. A total of 5170 earthworms were counted during the project with a mean of 8 earthworms per soil pit - equivalent to a density of 198 earthworms per m2. Soil moisture and texture were the largest drivers of total earthworm abundance, with habitat borderline statistically insignificant. Endogeic earthworms were found in 71 % of soil pits, epigeic in 62 % and anecic in 33 %. Fertiliser use also had a significant effect on total abundance, but only when organic fertiliser was used. Earthworm ecological groups demonstrated varied responses to habitat, with endogeic earthworms consistently the most abundant group, showing slight preferences for grasslands and vegetable beds. Anecic earthworms had the lowest abundance across all habitats but were more prevalent in grasslands and vegetable beds. Epigeic earthworms were most abundant beneath shrubs and hedges. These findings align with expected patterns of earthworm ecology, underscoring the potential of well-designed citizen science projects to yield valuable insights into urban earthworms and soil health.

Earthworm communities and their relation to above‐ground organic residues and water infiltration in perennial cup plant (Silphium perfoliatum) and annual silage maize (Zea mays) energy plants

AbstractPerennial energy cropping systems are hailed as a sustainable way of mitigating and potentially adapting to climate change. As a result of the absence of tillage, soils cropped with perennials like cup plant (Silphium perfoliatum) promote abundant and functionally diverse earthworm communities. Hence, ecosystem service provision because of earthworm activity and functional redundancy, for example, litter decomposition, water infiltration and nutrient turnover, is considerably enhanced in perennial cropping systems. We studied the abundance and functional role of earthworms in non‐tilled perennial systems and reduced‐tilled annual systems to assess their relationship with the respective above‐ground organic residues and their implications for the soil water dynamic. We sampled earthworms and simultaneously measured the saturated infiltration rate for two consecutive years in cup plant and maize (Zea mays) fields. Furthermore, we sampled above‐ground litter each trimester in both systems and analysed the total C and N content and CN ratios. Our field investigations revealed significantly higher earthworm abundance, species diversity and richness in cup plant systems likely because of the absence of tillage and the formation of a litter layer. High abundances of juveniles in both maize and cup plant systems pointed to harsh habitat conditions likely because of temperature variations, waterlogging and bulk density. The respective field litter was of minor importance as a food source in both systems because of poor quality, but may positively affect the soil water balance in cup plant systems. Earthworm populations in maize may have been supported by organic fertilizer while earthworm populations in cup plants may have additionally benefitted from the extensive root network and a higher on‐site plant diversity. Reduced tillage regimes in maize systems may have enhanced saturated infiltration rates. A direct link between earthworms and infiltration was not validated, but may not be excluded in the future, as earthworm populations may develop slowly because of adverse habitat conditions. Our results show that perennials support abundant and diverse earthworm populations and indicate the importance of functional redundancy and the diversity of food sources. The combination of both earthworm abundance and perennial cropping systems is capable of increasing on‐site ecosystem stability and supporting adaptation to climate change by increasing functional redundancy and, ultimately, providing ecosystem services. The noticeable occurrence of the latter, however, may be delayed because of the slow establishment of earthworm communities and delayed build‐up of ecosystems stability. Hence, a transitional phase is inevitable to reap the benefits of perennial energy cropping systems and must be accounted for.