Endogeic Species Research Articles

Functional diversity of earthworm communities in forests in the south of the Russian Far East

Key species of soil macrofauna – large soil saprophages, i.e. earthworms – have been studied in unique in terms of floristic and faunal diversity, as well as the most preserved forests of the southern Russian Far East. The results of studying taxonomic and functional diversity of earthworms, their biomass and abundance and patterns of temporal spatial distribution in summer seasons, are presented. The complete set of the main functional groups of earthworms (epigeic, epi-endogeic, endogeic and anecic) was found only in the best-preserved valley forests, with no traces of logging and fires over the last century. The earthworm community is not complete (one or two functional groups are missing) in one of valley forest that was partially cut down and affected by fires in recent decades and in hillside forests. Horizontal spatial distribution was analysed for the epi-endogeic and endogeic groups of earthworms, dominating in terms of biomass and occurrence. It was found that, in the summer season, the group of epi-endogeic species showed the "covering" type of distribution (regular distribution without aggregation), whereas the group of endogeic species showed the "spotty" type of distribution (aggregated distribution).

Effects of temporary grassland introduction into annual crop rotations and nitrogen fertilisation on earthworm communities and forage production

Earthworms contribute to a wide range of ecosystem services in agriculture. Most studies focusing on impacts of annual crop management on earthworm communities are related to soil tillage, fertilisation or pesticides, while the effect of introducing temporary grassland into an annual crop rotation remains largely unknown. In this context, the aims of the present study were to evaluate effects of (i) introducing grassland into a crop rotation, (ii) grassland duration and (iii) grassland fertilisation on earthworm communities and grassland forage production in a long-term experimental station in western France. Three years of highly fertilised (230 kg ha−1 yr−1 of mineral nitrogen) grassland preceded by three years of annual crop rotation was compared to an annual crop rotation without grassland and to six years of grassland either lightly (30 kg ha−1 yr−1 of mineral nitrogen) or highly (230 kg ha−1 yr−1 of mineral nitrogen) fertilised. Grassland introduction into a crop rotation significantly increased earthworm abundance, biomass, and diversity, especially for anecic species, and improved the functional structure of the earthworm community. Grassland duration and fertilisation increased earthworm abundance and biomass, especially for anecics, without affecting endogeic species and earthworm diversity. Grassland duration did not increase forage production, but the increase in fertilisation did. Three years of highly fertilised grassland significantly increased earthworm abundance and biomass, improved the functional structure of the earthworm community and produced as much forage per year as six years of highly fertilised grassland. Overall, the introduction of grassland into annual crop rotations appears an effective way to rapidly increase earthworm community parameters and, given the important role of earthworms in soils, enhance soil functioning.

Depth distribution of soil organic matter and burrowing activity of earthworms—mesocosm study using X-ray tomography and luminophores

Earthworms feed on organic matter present at the soil surface or within the soil. Thus, its distribution in the soil profile is likely to greatly influence earthworm behavior and, in turn, their burrow system. To test this idea, two anecic and two endogeic earthworm species were introduced into repacked soil cores (depth = 30 cm) upper half filled with a top soil containing 4% organic matter (0–15 cm) and lower half filled with a deep soil at 2% organic matter (15–30 cm). Earthworm behavior was studied using X-ray tomography combined with luminophores (colored particulate tracers of 63–125 μm size) placed at 0, 3, and 12 cm depth, a method widely used in sediment ecology. We observed that anecic and endogeic earthworms had contrasting reactions to the conditions with only endogeic species burrowing more intensively in the upper part. From a quantitative point of view, only a few percent of luminophores were displaced. However, luminophore displacements also provided qualitative information to complement the tomography: (i) endogeic species and especially Aporrectodea caliginosa bioturbated the most soil close to the surface (3 cm depth) and (ii) the two anecic species influenced the luminophore distribution differentially with Lumbricus terrestris displacing significantly more luminophores, whatever their initial depth, than Aporrectodea nocturna due to intense surface cast activity. Beyond methodological developments, our study found that endogeic earthworms burrow more in zones with higher organic matter contents and this explains why they are mainly found close to the soil surface in non-tilled soils.

Soil properties, grassland management, and landscape diversity drive the assembly of earthworm communities in temperate grasslands

Earthworms are widespread soil organisms that contribute to a wide range of ecosystem services. As such, it is important to improve our knowledge, still scanty, of the factors that drive the assembly of earthworm communities. The aim of the present study was to conjointly evaluate the effects on the assembly of earthworm communities of i) soil properties (texture, organic matter content, and pH), ii) grassland management (grassland age, livestock unit, and type of fertilization), iii) landscape diversity (richness, diversity of surrounding habitats, and grassland plant diversity), and iv) presence of hedgerows. The study was conducted in temperate grasslands of Brittany, France. Earthworms were sampled in 24 grasslands and, in three of these grasslands, they were sampled near a hedgerow or near a ditch (control without a hedgerow). Soil properties explained the larger portion of the variation in the earthworm community parameters compared to grassland management or landscape diversity. The increase in soil organic matter content and pH were the most favorable factors for earthworm abundance and biomass, in particular for endogeic species. Regarding grassland management, the increase in the livestock unit was the most damaging factor for earthworm communities, in particular for the anecic earthworm biomass and endogeic species richness. Surprisingly, landscape diversity negatively affected the total earthworm abundance and epigeic earthworm biomass, but it was related to an increase in the epi-anecic species. At a finer scale, we also demonstrated that the presence of hedgerows surrounding grasslands enhanced earthworm species richness, especially within the epigeic and anecic ecological categories. This study highlights that the earthworm ecological categories respond specifically to environmental filters; further studies need to be conducted to elucidate the factors that drive the assembly of earthworm communities at this ecological category level. We recommend that policymakers should act on landscape management to favor earthworm diversity in order to improve the ecosystem services they drive.

Hidden Engineers and Service Providers: Earthworms in Agricultural Land-Use Types of South Tyrol, Italy

Earthworm activities affect the provision of many ecosystem services. Land use can strongly influence earthworm communities and, hence related soil functions. We assessed earthworm biomass, abundance, and species composition on grasslands, apple orchards, and vineyards in the context of an existing sustainability assessment tool in South Tyrol, Italy. A stratified sampling campaign revealed significant differences in earthworm distribution. We found 21 to 700 individuals m−2 in grasslands and surprisingly abundant earthworm communities in apple orchards (14 to 382 individuals m−2). Results for vineyards were ambiguous with no or very low abundance in 47% of the vineyards and a maximum of 396 individuals m−2. Mesohumic endogeic species were the most abundant functional group observed (75% of the biomass in grasslands, 50% in apple orchards and vineyards). Aporrectodea caliginosa was the most abundant endogeic species, Lumbricus rubellus the dominant polyhumic endogeic species in all land-use types. We estimated a total of 34,900 t of earthworm biomass on agricultural areas in South Tyrol corresponding to a total value of EUR 872 million. Although soil quality is a complex concept that cannot be captured with a single indicator, earthworms are suitable and feasible indicators for sustainable soil use at the landscape scale.

Earthworm species and density in semi-natural grasslands on rice paddy levees in Japanese satoyama.

Earthworms contribute to the sustainability of food webs in the semi-natural grasslands of levees at paddy margins, which are typical components of satoyama, the traditional agricultural landscapes of Japan. Thus far, few studies have focused on earthworm fauna of paddy levees in satoyama. In this study, we investigated earthworm fauna and regional and monthly changes in earthworm density. We found at least 11 species of earthworms living within levees on Sado Island, central Japan. Two endogeic species, Amynthas corticis (Megascolecidae) and Eisenia japonica (Lumbricidae), were dominant in terms of number of adult individuals; these two species appeared in all study regions. We also estimated an average of ~57.4 individuals/m2 for all stages of earthworms in levees, suggesting that rice paddy levees have relatively-high earthworm density. However, such tendencies differed depending on the region. In addition, monthly changes in density were observed in the topsoil of the levees. Our results imply that differences in earthworm assemblages amongst regions and months may influence the availability of food resources for various animals inhabiting satoyama.

Elucidating pesticide sensitivity of two endogeic earthworm species through the interplay between esterases and glutathione S-transferases

Earthworms are common organisms in soil toxicity-testing framework, and endogeic species are currently recommended due to their ecological role in agroecosystem. However, little is known on their pesticide metabolic capacities. We firstly compared the baseline activity of B-esterases and glutathione-S-transferase in Allolobophora chlorotica and Aporrectodea caliginosa. Secondly, vulnerability of these species to pesticide exposure was assessed by in vitro trials using the organophosphate (OP) chlorpyrifos-ethyl-oxon (CPOx) and ethyl-paraoxon (POx), and by short-term (7 days) in vivo metabolic responses in soil contaminated with pesticides. Among B-esterases, acetylcholinesterase (AChE) activity was abundant in the microsomal fraction (80% and 70% of total activity for A. caliginosa and A. chlorotica, respectively). Carboxylesterase (CbE) activities were measured using three substrates to examine species differences in isoenzyme and sensitivity to both in vitro and in vivo exposure. CbEs were mainly found in the cytosolic fraction (80% and 60% for A. caliginosa and A. chlorotica respectively). GST was exclusively found in the soluble fraction for both species. Both OPs inhibited B-esterases in a concentration-dependent manner. In vitro trials revealed a pesticide-specific response, being A. chlorotica AChE more sensitive to CPOx compared to POx. CbE activity was inhibited at the same extent in both species. The 7-d exposure showed A. chlorotica less sensitive to both OPs, which contrasted with outcomes from in vitro experiments. This non-related functional between both approaches for assessing pesticide toxicity suggests that other mechanisms linked with in vivo OP bioactivation and excretion could have a significant role in the OP toxicity in endogeic earthworms.

Assessment of earthworm activity on Cu, Cd, Pb and Zn bioavailability in contaminated soils using biota to soil accumulation factor and DTPA extraction.

The study aims to investigate effect of earthworm activity on metal bioavailability in soils using their BSAF-metals. Based on a microcosmic laboratory experiment, epigeic species Amynthas corticis (A. corticis) and endogeic species Amynthas robustus (A. robustus) were cultured in two types of soils contaminated by Cd, Zn, Pb and Cu for 120 days. Earthworm characteristics (i.e. numbers, biomass and BSAF), soil properties (i.e. pH, organic C and N contents along with their components such as mineralization and microbial masses) and DTPA extracted metals in soil were determined. After the incubation, the biomass and survival numbers of both earthworm species decreased significantly (P<0.05). The accumulation of Cd, Zn and Pb in earthworm tissues and BSAF-metals were earthworm species dependent. According to two-way ANOVA, BSAF-Pb clearly showed the effect of different species of earthworms while BSAF-Cu indicated an interactive effect of earthworms and soil type. Earthworms changed soil properties significantly, especially for mineralized C (Cmin), dissolved N (Ndis) and pH (P<0.05). Earthworm activity increase DTPA extracted Zn and Cu, and the effect of A. robustus were stronger than for A. corticis. Redundancy analysis (RDA) showed that BSAF-Cu and BSAF-Pb contributed for respectively 51.9% and 51.7% of soil properties and DTPA metal changes, indicating that the effects of BSAF-Cu and BSAF-Pb on soil properties and on metal bioavailability in soil were similar. BSAF-Cu, indicating the interactive effect of earthworms and soil, accounted for 38.5% and 45.1% of soil properties and soil metal bioavailability changes. BSAF-Pb, representing the effect of earthworm species, accounted for 13.3% and 6.6% of soil property and soil metal bioavailability variations. Stepwise regression indicated that earthworm might change soil properties through their activities and interactions with soil, and hence increase heavy metal bioavailability. It suggested that BSAF is an important indicator for evaluating the effect of earthworm activity on soil metal bioavailability and designing remediation strategies.

Biotopic Association of Earthworms in Intact Forests of Teberda Nature Reserve

Contribution of micromosaic structure of high mountain forests to ecological diversity of earthworms have been assessed. Intact forests of Arkhyz section of Teberda Nature Reserve were studied. The dominant types of forests have been recognized for the first time based on eco-coenotic classification. The ecological conditions of their functioning have been studied. Earthworm numbers have been studied in the recognized forest types. Diversity of earthworms was studied in soils under crowns, under fallen trees, and in mosses growing on rocks. 16 species of Lumbricidae have been found, with 4 of them being discovered for the first time. Full complexes of Lumbricidae were associated with biotopes of forest types of increased soil moisture content, low acidity, availability of nitrogen and pronounced litter. The largest abundance, diversity and biomass of Lumbricidae have been found in nitrophilous tallgrass gray alder forests. The lowest have been found in xeromesophytic pine forests with fir, spruce and birch. The most widespread dark coniferous forest with beech were inhabited by seven species of Lumbricidae, dominated by the epigeic species. There were few epi-endogeic and anecic species. The endogeic group of earthworms was represented by Crimea and Caucasus subendemic Dendrobaena schmidti. Diversity and biomass of earthworms in dark coniferous forests with beech were higher than in spruce-fir forests. During summer, dead fallen trees served as a microsite preferential for epigeic and endogeic species, while mosses growing on rocks were preferred by endogeic species.

Large variations in readily-available phosphorus in casts of eight earthworm species are linked to cast properties

Phosphorus (P) is an important nutrient for plant growth. However, P is often poorly available for uptake by roots because it strongly adsorbs to the soil mineral phase. Recent research shows that earthworms can temporally and locally increase P availability to plants. However, the pathways through which they do so are not fully understood, and it remains unclear to what extent this capacity varies among earthworm species. Here we study the variation among earthworm species with respect to readily-available P in casts as well as other physico-chemical cast properties, in a greenhouse pot experiment using a soil with a low P status. The earthworms belong to eight commonly occurring earthworm species in the Netherlands: two epigeic species (a mixture of the compost earthworms Dendrobaena veneta/Eisenia fetida; Lumbricus rubellus); four endogeic species (Allolobophora chlorotica, Aporrectodea caliginosa, Aporrectodea rosea, Octolasion lacteum); and two anecic species (Aporrectodea longa; Lumbricus terrestris). For all species, the pH in water extracts of earthworm cast (pH = 7.4–8.2) was significantly higher (p < 0.001) than for the control bulk soil (pH = 6.6) and differed significantly (p = 0.003) among earthworm species. Similarly, the dissolved organic carbon (DOC) concentration in the same water extracts was an order of magnitude higher in earthworm cast compared to the control bulk soil and varied among species (p < 0.001). The size of the total pool of reversibly adsorbed P in earthworm cast was greater than in the control bulk soil, but no significant differences were found among earthworm species. Differences among species were present for the readily-available P pools extracted from casts, including P-Olsen and water-extractable ortho-P. Water-extractable ortho-P concentrations were much higher in the casts of all species as compared to the control bulk soil (0.9–6.8 vs 0.06 mg l−1 or to 9.0–68 vs 0.6 mg kg−1). Highest ortho-P levels were measured in L. rubellus casts and the lowest in casts of A. chlorotica. A positive correlation between the concentrations of DOC and ortho-P was observed (R2 = 0.72, p < 0.001). The observed variation in all measured physico-chemical cast properties could not be explained by conventional ecological earthworm classifications. Our results show that the nature and magnitude of earthworm-induced increased P availability differs dramatically among earthworm species. This strongly suggests that, apart from its size, species composition of the earthworm community is key to optimizing P availability to plants.

Fertilización con purín porcino: impacto sobre las lombrices de tierra en agricultura de secano

Earthworms play an important role in the maintenance of soil ecosystem services. Their presence and activity are influenced by agricultural practices as fertilization. The objective of this research was to identify earthworm species and to quantify their abundance and biomass in a field experiment where different fertilization strategies were applied for a period of 12 years. The experiment was carried out under a semiarid Mediterranean climate, in a fallow year of a rainfed cereal system. Fertilization strategies were based on pig slurries from fattening pigs (PE) and from sows (PM) at different fresh doses distributed in six treatments: three treatments only included PE (one rate was 30 t ha−1 yr−1 applied at pre-sowing, and the other two treatments received 40 and 60 t ha−1 yr−1 applied at cereal tillering), two treatments only included PM (60 and 90 t ha−1 yr−1 applied at cereal tillering) and the last, it combined PE and PM (30 t ha−1 yr−1 of PE at pre-sowing plus 90 t ha−1 yr−1 of PM at cereal tillering). Fertilization included a mineral fertilization treatment (0−FM) acting as a control. There were no variations in the abundance and biomass of earthworms registered according to the type of fertilization. Two earthworm species were identified. The endogeic species Koinodrilus roseus was the most abundant (80%−100%). The anecic species Nicodrilus trapezoides was not detected in plots receiving the two highest doses of PE at cereal tillering. The absence of N. trapezoides can be considered as a bioindicator of PE over-fertilization.

Seasonal variations in exotic earthworm populations in wheat fields of the Inland Pacific Northwest, U.S.A.

Through their manipulation of soil physical and chemical properties, earthworms have the potential to increase nutrient mineralization and benefit crop production. However, this effect is dependent on numerous factors including earthworm densities and ecological strategies. In addition to impacting density, soil environmental conditions may limit earthworm activity to specific times during the growing season, moderating their effects on nutrient availability and crop growth. The purpose of this study was to determine the active period of earthworms to better assess their potential impact on crop productivity in dryland wheat production systems in the Palouse region of northern Idaho and eastern Washington, U.S.A. Earthworm community density, age structure, diversity, and soil moisture and soil temperature were monitored over a 14-month (April 2014–June 2015) period in six dryland wheat fields. All earthworms collected were exotic species, with the endogeic species, Aporrectodea trapezoides being predominant at all sites (87% of all adults identified). Allolobophora chlorotica, Lumbricus terrestris and Aporrectodea tuberculata were collected at lower frequencies (1.8–6.4% of adults). Mean densities ranged from 14 to 75 individuals m−2, and populations transitioned to aestivation beginning in mid-June of both years. All earthworms were active (no aestivating individuals) on 56.9% of the sampling dates in 2014 and 71% of the days in 2015. A short active period and average densities at most sites of less than 100 individuals per m2 suggest that the impact of earthworms on crop growth may be limited in conventional, dryland agricultural fields of this region.

Tree species identity governs the soil macrofauna community composition and soil development at reclaimed post-mining sites on calcium-rich clays

We tested the effect of main soil characteristics and tree species on earthworm community composition and abundance in reclaimed spoil heaps planted with five different tree species. Earthworm and soil macroarthropod abundance and biomass were highest in alder plantations, followed by oak plantations. The numbers of soil macrofauna were positively correlated with the total soil N content, which was highest in alder plantation. The correlation was strongest for endogeic earthworms (genus Aporrectodea and Octolasion). Soil moisture, measured in top 10 cm, affected only endogeic species. Other soil variables (pH, Ca) did not have a strong effect on earthworms. The earthworm community composition was similar in alder and oak, with most species occurring at both types of forest; however, in alder forest the epigeic species Dendrobaena octaedra was more common, whilst in oak forest the epigeic earthworms form genus Lumbricus were more abundant (L. rubellus and L. castaneus). The anecic species Aporrectodea longa was more abundant at alder sites, but L. terrestris was more abundant under oak. The alder forest was characteristic by a thick humus layer (10–15 cm), which at oak and larch sites was thinner (4–7 cm) and at pine and spruce stands was absent. Soil compaction was lower under the deciduous trees (alder, oak, larch), than under spruce and pine. We conclude that the alder plantations have most palatable litter and lowest C/N ratio and therefore support the highest numbers of soil macrofauna, which affects the humus layer thickness and soil compaction in the surface layers.

Restoration of Earthworms Community (Oligochaeta: Lumbricidae) at Sand Quarries (Smolensk Oblast, Russia)

The earthworm community formation studies have been carried out during the primary succession at the sand quarries formed during the sand mining. It has been established that the earthworm colonization during the 7 – 50 years sand quarry overgrowth is slow and the species composition is not fully restored therewith. The quarries are mainly occupied with the endogeic species. The results of the experiment on the introduction of the species of earthworms of different morpho-ecological groups have been described for the quarries at different stages of restoration. It has been established that the endogeic species colonization is advisable at the initial stages of the quarry overgrowth and the epi-endogeic, epigeic and anecic species colonization – at the later stages.

Invasive earthworm and soil litter response to the experimental removal of white-tailed deer and an invasive shrub.

Recent studies have shown that complex species interactions can regulate above- and belowground processes in terrestrial systems. Ungulate herbivory and invasive species are known to have strong effects on plant communities in some systems, but their impacts on soil biota and belowground processes are lesser known. Growing evidence suggests white-tailed deer (Odocoileus virginianus) and invasive plants facilitate increased abundance of exotic earthworms in temperate forests of the eastern United States. We conducted an experimental study that manipulated deer access and the presence of an invasive understory shrub in an eastern deciduous forest of southwestern Ohio, USA, from 2013 to 2017. Earthworm density and biomass, and standing litter biomass were measured in five paired deer access and exclosure plots, each with a split-plot removal of Amur honeysuckle (Lonicera maackii). Earthworm density declined in response to the experimental exclusion of deer, with earthworm density decreasing over time in the deer exclosure plots relative to deer access plots. Deer exclusion produced greater variation in earthworm species composition relative to access plots. Multivariate analyses indicated that larger earthworms in the genus Lumbricus were associated with deer exclosure plots, while smaller endogeic species were ubiquitous in both treatments. Standing litter biomass decreased over time in the deer-access plots. In contrast, honeysuckle removal had little effect on earthworm density and standing litter biomass. There was an interaction between deer and honeysuckle treatments on earthworm biomass, with honeysuckle removal reducing earthworm biomass when deer were excluded. Our results demonstrate strong effects of herbivores on invasive earthworms and ecosystem processes, but indicate a weaker influence of invasive shrubs. Further, our findings suggest that the effects of deer overabundance in forest ecosystems are potentially reversible with long-term intervention.

Impact of five different species of bamboo plantations on earthworm communities in West Tripura (India)

A field study undertaken in 5 different species of bamboo plantations in West Tripura revealed presence of 18 species of earthworms belonging to 4 different families viz Megascolecidae [Metaphire houlleti (Perrier), Kanchuria sp1, Lampito mauritii Kinberg, Amynthus alexandri (Beddard), Perionyx excavatus Perrier, Metaphire posthuma (Vaillant)], Octochaetidae [Eutyphoeus gigas Stephenson, Eutyphoeus comillahnus Michaelsen, Eutyphoeus orientalis (Beddard), Dichogaster bolaui Michaelsen, Lennogaster chittagongensis (Stephenson), Lennogaster yeicus (Stephenson), Eutyphoeus turaensis Stephenson and Octochaetona beatrix (Beddard)], Moniligastridae [Drawida assamensis Gates, Drawida nepalensis Michaelsen and Drawida papillifer papillifer (Stephenson) and Glossoscolecidae (Pontoscolex corethrurus Muller). One species E. comillahnus is restricted only to Tripura of India. Bamboo plantations were mostly dominated by endogeic (geophagous) species. Among the plantations B. polymorpha had the highest density (175 ind./m2) and biomass (75 g/m2) of the earthworms, whereas the highest earthworm diversity (Ĥ 1.67) was found in B. cacharensis plantation.

Combining bulk and amino acid stable isotope analyses to quantify trophic level and basal resources of detritivores: a case study on earthworms.

Quantification of the bacterial, fungal, and plant energy channels to the nutrition of detritivores is methodologically challenging. This is especially true for earthworms that ingest large amounts of litter and soil mixed with microorganisms. Novel methods such as compound-specific stable isotope analysis (CSIA) of C and N of individual amino acids promise major progress in this field in comparison with bulk stable isotope analysis (bulk SIA). Here, we combine CSIA and bulk SIA of carbon and nitrogen to quantify the linkage of epigeic and endogeic earthworm species to different energy channels across boreal and temperate forest ecosystems. The results showed pronounced flux of energy directly from plants to earthworms (33-50% of essential amino acids, EAA) refining the position of earthworms in soil food webs as both competitors and consumers of microorganisms. Epigeic earthworm species primarily relied on plant litter and endogeic species primarily relied on bacteria and soil organic matter. The linkage of both groups to plant or microbial energy channel was likely driven by the quality of detritus. Both bulk 15N and 13C enrichments were related to the trophic level of earthworms. Furthermore, 15N enrichment was related to the proportions of bacterial and plant EAA in the diet. Strong negative correlation between trophic level (CSIA of nitrogen) and the proportion of plant EAA (CSIA of carbon) suggests that both novel methods can indicate the degree of microbivory in detritivores. CSIA of amino acids provide detailed and baseline-independent information on basal resources and trophic levels of detritivores.

New species of Glossoscolex and Fimoscolex earthworms (Oligochaeta: Glossoscolecidae) from Embrapa Forestry, Paraná, Brazil.

Three new earthworm species in two genera of the Glossoscolecidae family, common in Southern and Southeastern Brazil, collected in the highland plateaus of Paraná, are described: Glossoscolex (Glossoscolex) maschio sp. nov. and Glossoscolex (Glossoscolex) embrapaensis sp. nov., and Fimoscolex nivae sp. nov. G. embrapaensis is a small, unpigmented endogeic belonging to the truncatus species group, having male pore on segment 17, while G. maschio is a large, pigmented epiendogeic species belonging to the giganteus species group, having male pore on segment 19. F. nivae is a very slender, small unpigmented endogeic species. All specimens were collected in native Araucaria forest on the grounds of Embrapa Forestry, but G. maschio was found exclusively associated with native forest, while G. embrapaensis and F. nivae were also collected in Eucalyptus, Pinus or Araucaria plantations, native grassland or fallow land, indicating their resistance to soil disturbance and land use change.

Urban land-use impacts on composition and spatiotemporal variations in abundance and biomass of earthworm community

Soil fauna can sensitively respond to alterations in soil environment induced by land-use changes. However, little is known about the impact of urban land-use changes on earthworm communities. In this study, three land-use types (i.e., forest, nursery and abandoned lands) were chosen to identify differences in diversity, abundance and biomass of earthworm community in Kunming City. Urban land-use had a pronounced difference in species composition, evenness and diversity of earthworm communities. Forest land had the highest density, biomass and diversity of the earthworm communities. Total abundance was dominated by endogeic species in nursery land (70%) and abandoned land (80%), whereas in the forest land, the earthworm community comprised epigeic, endogeic and anecic species. Temporal changes in earthworm density and biomass were also significantly affected by land-use change. Total density and biomass of earthworms in the forest and nursery lands were highest in September, but highest in the abandoned land in October. The influence of soil physicochemical properties on the earthworm density and biomass also varied with land-use types. Soil temperature significantly affected earthworm density and biomass in the three land-use types. Soil pH was positively correlated with earthworm biomass in the forest land, but negatively associated with earthworm density in the abandoned land. Soil organic matter was positively correlated only with density and biomass of earthworms in the nursery and abandoned lands. Our results suggest that the species composition, abundance and biomass of earthworm communities can be determined by the modification of soil properties associated with urban land-use type.

Current knowledge of earthworm richness and distribution in Santa Fe province, Argentina

Updated list of earthworms (Oligochaeta: Lumbricina) from Santa Fe (Argentina) is presented in this work, including current data of species richness and territorial distribution status and information collected by Ljungström and collaborators 40 years ago. Field samplings were conducted between 2012 and 2015 at 23 sites, located in 11 of the 19 districts of the province. Earthworms were collected following a standard methodology (Tropical Soil Biology and Fertility). The conservation of specimens was done with 4 % formalin solution and their identification was performed according to taxonomy keys. Richness, similarity and complementarity of species between the phytogeographic provinces were analyzed. A total of 15 earthworm species were identified and grouped into ten genera and five families: Acanthodrilidae (Dichogaster bolaui, Microscolex dubius), Glossoscolecidae (Glossodrilus parecis), Lumbricidae (Aporrectodea caliginosa, Aporrectodea rosea, Aporrectodea trapezoides, Bimastos parvus, Eisenia fetida, Octolasion tyrtaeum), Megascolecidae (Amynthas gracilis, Amynthas morrisi, Metaphire californica), Ocnerodrilidae (Eukerria saltensis, Eukerria rosea, Eukerria stagnalis). From all the species found five, G. parecis, E. saltensis, E. rosea, E. stagnalis and M. dubius, are native to South America, and the rest were introduced from Asia and Europe. The Espinal presented the greatest richness of earthworms (12), while the Pampeana showed high values of complementarity (greater than 70 %) with the Chaco Húmedo and Valle de Inundación del Río Paraná. Endogeic species were present in all environments surveyed. In particular, the exotic species A. trapezoides and A. morrisi showed a wide geographical distribution, having been found at 70 and 50 %, respectively, of the total number of the studied sites. One species, E. rosea, which is in the list, was not recorded in the sampling of 40 years ago. The results of current survey show that the number of species was lower compared to study by Ljungström and collaborators (60 % of the 23 species registered). Possibly the remarkable change in the richness and distribution of earthworms could be a process associated with changes in soil use and land management developed over 40 years.