Earthworm ecology Research Papers - Academia.edu (original) (raw)

Crop residue mulching combined with zero tillage and crop rotation, known as conservation agriculture (CA), is being promoted as an alternative system to revert soil degradation in maize-based farming in the central highlands of Mexico. The goal of this paper was to determine the effects of CA vs. conventional tillage systems on soil quality, with a special focus on the role of earthworms in affecting the soil structure morphology, and on crop yield. For the conventional tillage system, the effect of crop residue retention (CONV + RES) was also compared to the conventional farmers’ practice (residues removed; CONV). CA resulted in four times higher earthworm abundance when compared to CONV. Residue retention per se (CONV + RES) did not favor earthworm abundance. In all cases the earthworm community was dominated by exotic species. CA increased total N and soil organic C concentrations relative to CONV, but only at 0–5 cm soil depth. Nevertheless, the more pronounced vertical stratification of soil organic carbon content under CA favored soil surface aggregation and aggregate stability as expressed by the aggregate mean weight diameter after dry sieving (MWDds = 2.6 mm for CA and 1.6 mm for CONV) and wet sieving (MWDws = 0.9 mm and 0.6 mm, respectively). Also, CA improved topsoil water stable macroaggregation (WSA = 415 mg g−1) when compared to CONV (251 mg g−1). Residue retention within conventional tillage (CONV + RES) led to small increases in topsoil aggregate stability (i.e. MWDds and WSA). Soil structural improvements were accompanied by a higher direct surface water infiltration. Micromorphological analysis of thin sections indicated a loose and highly biogenic soil microstructure in CA, whereas CONV was characterized by a physicogenic microstructure, despite similar soil bulk densities (SBD). SBD is thus a poor indicator of soil physical quality when comparing different tillage systems. Redundancy analysis illustrated that CA resulted in improvement in most parameters related to soil quality, especially at the soil surface, but significant yield increases were recorded only in 2004. CONV + RES lead to marginal improvements in soil quality with no yield increases.

- by
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- Sustainable agriculture, Sustainable Agriculture (Environment), Earthworm ecology, Mexico

Improperly managed organic waste constitutes a serious environment threat across the globe. This has led to a worldwide struggle to strike a balance between the rapid generation of such wastes and protection of the environment. With the unique advantages of lower operational and maintenance costs compared with other waste management technologies, the use of vermicom-posting to manage organic wastes has been increasing rapidly in recent years. Still, some factors (e.g., characteristics of substrate composition before and after treatment) are in need of additional , specific studies so that researchers can better understand the metabolism involved in the process. Vermicomposting provides employment opportunities as it protects the environment, augmenting crop productivity when it is used as a fertilizer supplement and helping to maintain ecological balance. Thus, vermicompost plays an important role in the circular economy. This article provides an overview of the research activities that have been conducted on the use of ver-micomposts to remove pollutants from the soil, in wastewater treatment, and in organic waste recycling throughout the world. Circular economic assessment has revealed that vermicompost-ing technology is usually feasible except in certain cases. Most other methods of waste disposal lead to soil deterioration, toxic effects, and increased pollution affecting land, air, water, and living beings, in addition to the sometimes considerable expense of their implementation. Thus, an eco-friendly method that removes waste in one step is needed. Determining the long-term performance and sustainable operation of vermicomposting systems still poses a challenge, however, as treatment performance is affected by design parameters, operational conditions, and environmental factors. This article summarizes the factors influencing pollutant removal through the ver-micomposting process. Finally, this article highlights additional research that should be conducted on these issues to improve the performance of vermicomposting.

Beberapa tanah dapat tercemar logm berat yang akan berdampak ke lingkungan juga ke biota tanah. Salah satu biota tanah yang responsive terhadap logam berat adalah cacing tanah. Cacing tanah mampu mengakumulasi logam berat di tubuhnya sehingga cacing tanah mampu menjadi bioindikator logam berat. Tujuan dari makalah ini adalah utuk mengetahui peran ccaing tanah pada tanah dan mengetahui peran cacing tanah sebagai indikator logam berat di tanah. Metode yang digunakan adalah dengan mencari studi pustaka. Logam berat yang dibahas adalah Arsenik (As), Kromium (Cr), Tembaga (Cu), Seng (Zn), Kadmium (Cd), dan Timbal (Pb). Semua logam berat diatas dapat terakumulasi oleh cacing tanah dalam jaringan tubuhnya dimana dapat mengakibatkan kerusakan pada jaringan tubuh bahkan kematian. Penyerapan logam berat pada cacing tanah setiap jenis logam berat berbeda-beda. Selain itu spesies cacing tanah juga mempengaruhi jumlah penyerapan oleh cacing tersebut.

- by Umi Hani
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- Soil Science, Bioindicators, Earthworm ecology, Heavy metals

Earthworms play an important role in the functioning of many terrestrial ecosystems, and while their importance is frequently acknowledged signiﬁcant challenges still remain in determining their operant roles within the soil. This lack of knowledge becomes increasingly important as the spatial scale of
analysis increases from individuals to populations within the landscape. To effectively develop understanding,
research techniques must be able to determine the effects that earthworms have on the soil system, as well as to establish how many and which species are present. A range of techniques are required to facilitate meaningful analysis from the micro-scale within a soil proﬁle (e.g. drilosphere
effects) to a ﬁeld scale or landscape scale. Furthermore, an additional framework of understanding is required to investigate the role of earthworms in the biogeochemical cycles.
By critically evaluating recent advances in methods and data analysis techniques in three areas of earthworm research we highlight that combinations of common approaches often offer the most significant insights into the functional roles of earthworms within a soil system. Through particular reference to earthworm sampling and identiﬁcation, biochemical functions and persistent pollutant ecotoxicology of
temperate ecosystems we emphasise how a range of investigation methods can be a hindrance to developing
a whole-system level understanding. The complex and diverse nature of soil systems means that a traditional compartmentalised approach studying single species using a single research technique is no longer sufﬁcient to gain further insights into the earthworm contribution to ecosystem goods and services delivered at the whole landscape scale. The integration of technologically advanced methods in combination with systems based modelling will be critical to develop landscape scale understanding of the functions of earthworms as individuals and as populations within in their ecosystems.

- by Maria J I Briones
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- Earthworm ecology, Earthworms, Earthworm Sampling

The effects of earthworms Eisenia spp. on microorganisms of three different habitat soil, compost, and
vermiculture were studied. Microbial communities of gut and fresh faeces of earthworms and substrates,
the worms were collected from, were analysed. Microbial biomass and composition of the total microbial
community were examined using phospholipid fatty acid (PLFA) biomarkers. Archaeal and bacterial
communities were studied by polymerase chain reaction-denaturing gradient gel electrophoresis
(DGGE). The culturing methods were used for assessment of counts, species richness and growth strategy
of bacteria.
In comparison with the substrates, the viable microbial biomass and the group of non-ester-linked
PLFAs indicative of anaerobes were higher in both the gut and faeces of all earthworm populations.
The prokaryotic community evaluated using DGGE revealed that archaeal community structure in the gut
and faeces of earthworms from populations differed from that in substrates, whereas the passage
through the gut had less influence on the bacterial community structure, particularly in compost and
vermiculture.
The counts of culturable bacteria increased due to gut passage only in forest and vermiculture populations.
The fast-growing bacteria increased due to gut passage only in forest soil population. Actinobacteria
(Arthrobacter, Microbacterium, Lechevalieria and Nesterenkonia) and Firmicutes (Bacillus and
Paenibacillus) were generally favoured in substrates and their species richness decreased with gut passage,
whereas Gammaproteobacteria (Aeromonas, Enterobacter, Pseudomonas and Salmonella) dominated
in gut contents. The impact of earthworm activity on the microbial community was higher in nutrientpoor
forest soil than in nutrient-rich compost and vermiculture substrates.

- by Alica Chronakova and +1
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- Environmental microbiology, Earthworm ecology, Archaea, Composting

Polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) were monitored over 56 days in calcareous contaminated-soil amended with either or both biochar and Eisenia fetida. Biochar reduced total (449 to 306 mg kg−1) and bioavailable (cyclodextrin extractable) (276 to 182 mg kg−1) PAHs, PAH concentrations in E. fetida (up to 45%) but also earthworm weight. Earthworms increased PAH bioavailability by >40%. Combined treatment results were similar to the biochar-only treatment. Earthworms increased water soluble Co (3.4 to 29.2 mg kg−1), Cu (60.0 to 120.1 mg kg−1) and Ni (31.7 to 83.0 mg kg−1) but not As, Cd, Pb or Zn; biochar reduced water soluble Cu (60 to 37 mg kg−1). Combined treatment results were similar to the biochar-only treatment but gave a greater reduction in As and Cd mobility. Biochar has contaminated land remediation potential, but its long-term impact on contaminants and soil biota needs to be assessed.

- by Tom Sizmur
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- Soil Science, Environmental Remediation, Trace element Geochemistry, BIOCHAR

The importance of earthworms to ecosystem functioning has led to many studies on the impacts of metals on earthworms. Far less attention has been paid to the impact that earthworms have on soil metals both in terms of metal mobility and availability. In this review we consider which earthworms have been used in such studies, which soil components have been investigated, which types of soil have been used and what measures of mobility and availability applied. We proceed to review proposed reasons for effects: changes in microbial populations, pH, dissolved organic carbon and metal speciation. The balance of evidence suggests that earthworms increase metal mobility and availability but more studies are required to determine the precise mechanism for this.

- by Tom Sizmur
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- Soil Science, Biogeochemistry, Soil, Trace element Geochemistry
- by Martin Shipitalo
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- Earthworm ecology

To link earthworm burrow distribution with the spatial variability of soil functions, accurate mapping of their spatial burrowing patterns is required. Eight natural soil cores (25 cm in diameter; up to 60 cm long) were collected from a pasture in spring 2001–2003. Earthworm populations were sampled on the first date and the anecic species Nicodrilus giardi was found to be dominant (55% of the average density of 101 worms m−2). Soil cores were imaged using medical X-ray tomography equipment. These tomography images served as a basis for 3D reconstructions generated using specifically written software. Finally, the reconstructed burrow systems were measured and analysed using mathematical morphological approaches. The 3D reconstructions thus derived showed dense systems of interconnected burrows. A number of burrows extending vertically from the top to the bottom of the cores, but most were short, disconnected burrows. These two classes of burrows could not be linked with the activity of a particular species. In addition to the visual appraisal of the burrow system shape, structural parameters such as burrow volume, burrow wall surface area, burrow length density, topology and burrow angles were computed from the 3D reconstructions. Total burrow length density ranged from 687 to 1212 m m−3. Burrow volume density represented less than 2.5% of total soil volume and ranged from 13.3 × 103 to 24.2 × 103 cm3 m−3. Inspite of the apparently high continuity of burrows, only 9–43% of the volume was connected to the soil surface. Total burrow wall area ranged from 7721 to 12764 cm2 m−3 while surface-connected burrow wall surface area ranged from 1069 to 7237 cm2 m−3. The drilosphere volumes (i.e. a 2 mm thick sheath around burrows) were estimated to range from 44.9 × 103 to 52.9 × 103 cm3 m−3. Earthworm activity was found to vary throughout the year as revealed by changes in burrowing patterns. The burrow systems in spring 2001 were denser than that in others years, and the burrow systems in spring 2003 appeared to be partially re-filled close to the surface. This temporal variability demonstrates that it is virtually impossible to obtain true replicates of burrow systems of a given earthworm community without knowing (1) which burrows were created by which species and (2) the burrows age. However, the accurate description and quantification of earthworm burrow systems using powerful image processing tools allows a detailed discussion of the potential impact of earthworms on soil functions under natural conditions.

- by Francois Bastardie
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- X-ray Tomography, Soil ecology, Earthworm ecology, Preferential Flow

The occurrence of the exotic earthworm species Metaphire bahli (Gates, 1945) of the family Megascolecidae is recorded for the first time from India. Specimens were collected from the Alappuzha District of Kerala State. Its detailed... more

To test the assumption that different earthworm species make differently-structured burrow systems that can affect water permeability, the burrow systems made by adults of three earthworms species (Lumbricus terrestris, Nicodrilus giardi and Octalasion lacteum) were studied in repacked soil cores (20 cm diameter by 40 cm high) under controlled conditions of temperature and humidity. Five core were used for each species and one adult earthworm was incubated per soil core over 21 days. Three-dimensional reconstruction (skeletons and volumetric images) of the burrow systems was performed and characterized after computer analysis of the 2D-slices from X-rays tomography. Total burrow length, number of burrows, branching rate, connectivity, burrow continuity, mean verticality and mean sinuosity of the burrows were measured from the skeletons. Differences were found between species in burrow characteristics: only one vertical and continuous burrow with large diameter for L. terrestris; long and complex burrow systems with branching burrows for N. giardi and O. lacteum. Moreover, 3D volume reconstruction of burrow systems enabled determination of the total volume, the distributed burrow volume as a function of depth and, using the tools of mathematical morphology, the pore size distribution of burrows. Results showed that the burrow volume of N. giardi was the highest; the three species had a unimodal pore size distribution centered on 8, 7 and 5 mm in diameter for L. terrestris, N. giardi and O. lacteum, respectively. Saturated hydraulic permeability was measured for each core and predicted using a water flow model. Significant differences between species were found, the burrow systems made by N. giardi being the most efficient for water flow. Differences in hydraulic properties between species resulted mainly from the difference in burrow continuity, the presence of openings at the soil surface and the burrow depth penetration.

- by Francois Bastardie
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- X-ray Tomography, Soil ecology, Earthworm ecology, Preferential Flow

Trichoderma species are endophytic plant opportunistic symbionts and ubiquitous in nature. They have potential as biocontrol agents of various plant diseases as well as help in improving crop production. Trichoderma species shows symbiotic association with apoplastic part of plant roots and has direct effect on plants. It has positive effects on seed germination, plant nutrient uptake and inorganic fertilizer efficiency, thus helps in improving plant growth and yield. In the present study, Trichoderma asperellum T42 strain was used to investigate its effect on pea (Pisum sativum) plant and biomass in the soil. Trichoderma treated pea seeds showed increased percentage of germination rate as compared to control plants. Apart from that, induced root and shoot development, increased photosynthetic pigment (chlorophyll), carotenoid, total sugar and protein content as compared to control plants were observed. Our study suggested that Trichoderma asperellum T42 can be used as plant growth promoting fungus similar to other Trichoderma species for sustainable agricultural practices. Therefore, it could be helpful in minimizing the rampant use of chemical fertilizers for improving agricultural and horticultural practices thus improving sustainability of agriculture. Keywords : Chlorophyll content, Pisum sativum, Seed germination, Sustainable agriculture, Trichoderma asperellum T42.

- by Gopal S. Singh
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- Pharmacology, Biochemistry, Botany, Pharmacy

This is a reporting on the occurrence of little known species of earthworm Megascolex lawsoni (Bourne, 1886), of the Family Megascolecidae for the first time from the political boundary of the State of Kerala. Specimens were collected from 12 locations within Wayanad District. So far, they have been reported from neighbouring states of Tamil Nadu and Karnataka. Its current geographical distribution and information on certain aspects of its biology are provided.

- by S Prasanth Narayanan
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- Earthworm ecology, Earthworms, Earthworm taxonomy
- by Daniel Cluzeau
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- Soil Science, Water, Biology, Soil ecology

This is not a traditional abstract philosophical piece of work, but instead it is abstract in its very nature. It is an emotional piece, which is intended to be experienced as such by you, the reader. It is created in fragments, driven by an inquisitive ness to read everything, an anxiety to include everything and the fear to commit to anything.
I will be thinking about disintegration from my personal experience of a psychological breakdown and ongoing mental illness, using this as an analogy for the breakdown of our relationship with nature and the consequential disintegration of the environment.
I have become fascinated by the indispensable and overlooked deep-burrowing earthworm, Lumbricus Terrestris who is returned to repeatedly as an investigative device to examine empathy, perspective, transformation and the creative process. In order to better understand our absurd relationship with nature, I will look at the respective evolutionary developments of both Lumbricus Terrestris and us, Homo Sapiens and will trace the origins of humans’ destructiveness of nature and the developments that have taken us to the epoch of the Anthropocene.
I will look at the role of both art and nature in the reintegration of mental and physical well-being, again using this as an analogy for our re-integration with our planet and the role that art can play in thinking about these ideas in order to develop a better understanding and caring relationship for our natural environment.
In order to gain a deeper understanding of the small-brained six-hearted worm and what we, the big-brained Homo Sapiens can learn from him, both species will morph into the other’s role in order to experience their being and learn from it.
Disrupted by episodes of depression and spells of insanity, the writing includes sections of creative writing based on autobiographical experience.
The writing makes visible the process of its own creation, language as image and form. Both the disintegration as well as the re-integration through the digestion of its very fragments and their regurgitation into the concluded piece.
It is the result of the intuitive process which I use to feel my way through the creation of my work. Bergson describes this method as intuitively feeling one’s way intellectually into the inner heart of a thing to locate what is unique and inexpressible in it.
(Henri Bergson, ‘The Creative Mind: Philosophical Intuition’, in Henri Bergson: Key writings, edited by Keith Ansell-Pearson and John Mullarkey (New York: Continuum International Pub- lishing Group, 2002), pp. 233 - 247.)

- by Myka Baum
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- Environmental Science, Human Evolution, Climate Change, Nature Culture

Herbicide use is increasing worldwide both in agriculture and private gardens. However, our knowledge of potential side-effects on non-target soil organisms, even on such eminent ones as earthworms, is still very scarce. In a greenhouse experiment, we assessed the impact of the most widely used glyphosate-based herbicide Roundup on two earthworm species with different feeding strategies. We demonstrate, that the surface casting activity of vertically burrowing earthworms (Lumbricus terrestris) almost ceased three weeks after herbicide application, while the activity of soil dwelling earthworms (Aporrectodea caliginosa) was not affected. Reproduction of the soil dwellers was reduced by 56% within three months after herbicide application. Herbicide application led to increased soil concentrations of nitrate by 1592% and phosphate by 127%, pointing to potential risks for nutrient leaching into streams, lakes, or groundwater aquifers. These sizeable herbicide-induced impacts on agroecosystems are particularly worrisome because these herbicides have been globally used for decades.

- by Johann Zaller and +1
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- Earth Sciences, Soil Science, Ecosystem Services, Organic agriculture

The impact of different seasons on the population of earthworm species viz. Lampito mauritii, Amynthasmorrisi and Dichogaster bolaui were studied in three different habitats (i.e., agricultural, garden and waste lands) of Sirohi district of Rajasthan. Highest population of Dichogaster bolaui was recorded in garden in August, whereas its population was low in waste land. The earthworm Amynthas morrisi was abundant in garden but poor in waste land. Maximum population of Lampito mauritii was in agricultural land and but its minimum population was found in waste land. The highest numbers of all three species (viz. Lampito mauritii, Amynthas morrisi, Dichogaster bolaui) were observed in the rainy season (July-Aug.). The populations of the earthworm species were meager in the months of summer (May) and winter (December-January). Earthworms showed their peak population during July-August and the second population peak was observed in February-March. The results suggested that these earthworm species breed twice in a year indicating two population peaks in different habitats of Sirohi district of Rajasthan.

- by Suresh Kumar
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- Population Dynamics, Earthworm ecology, Earthworm Density

The effects of earthworms on soil CH4 emissions remain ambiguous, as previous studies revealed both
positive and negative effects on net rates of CH4 production. These differences may be linked to land-use
history such as pasturing intensity, as the treading of livestock and the input of faeces will affect physical
and chemical soil characteristics that are important to methanogenic and methanotrophic bacteria. In
order to concomitantly measure the effects of earthworms on the activities of both of these bacterial
groups, we performed an isotope dilution assay to measure gross CH4 production and consumption rates.
Samples from three soil types, differing mainly in pasture intensity over the past 15 years, were incubated
for 8 weeks in the presence or absence of the vermicomposting species Eisenia andrei. Following
the incubation, earthworms had a positive effect on gross process rates in the non-pasture control soil,
had no effect in the moderate pasture soil, and had a negative effect in the intensive pasture soil.
Phospholipid fatty-acid profiles and chemical characteristics of the fresh soil samples suggested that the
non-pasture soil would likely produce less CH4 than the control soil. Likewise, methanogenic specific
mcrA gene abundance following the incubation was two orders of magnitude higher in the two pasture
soils than in the control soil. The isotope dilution assay revealed, however, higher gross CH4 production
rates in the control soil. It was also found that gross CH4 transformation rates were neither correlated to
net production rates nor to mcrA gene abundance. We discuss the value and limitations of the isotope
dilution assay for understanding the factors and underlying mechanisms governing net CH4 emissions
rates from soils.

- by Alica Chronakova
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- Soil Science, Earthworm ecology, Methane, Soil Microbiology

To assess the risks that contaminated soils pose to the environment properly a greater understanding of how soil biota influence the mobility of metal(loid)s in soils is required. Lumbricus terrestris L. were incubated in three soils contaminated with As, Cu, Pb and Zn. The concentration and speciation of metal(loid)s in pore waters and the mobility and partitioning in casts were compared with earthworm-free soil. Generally the concentrations of water extractable metal(loid)s in earthworm casts were greater than in earthworm-free soil. The impact of the earthworms on concentration and speciation in pore waters was soil and metal specific and could be explained either by earthworm induced changes in soil pH or soluble organic carbon. The mobilisation of metal(loid)s in the environment by earthworm activity may allow for leaching or uptake into biota.

- by Tom Sizmur
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- Biogeochemistry, Trace element Geochemistry, Contaminated Land, Earthworm ecology

The common practice of remediating metal contaminated mine soils with compost can reduce metal mobility and promote revegetation, but the effect of introduced or colonising earthworms on metal solubility is largely unknown. We amended soils from an As/Cu (1150 mgAs kg−1 and 362 mgCu kg−1) and Pb/Zn mine (4550 mgPb kg−1 and 908 mgZn kg−1) with 0, 5, 10, 15 and 20% compost and then introduced Lumbricus terrestris. Porewater was sampled and soil extracted with water to determine trace element solubility, pH and soluble organic carbon. Compost reduced Cu, Pb and Zn, but increased As solubility. Earthworms decreased water soluble Cu and As but increased Pb and Zn in porewater. The effect of the earthworms decreased with increasing compost amendment. The impact of the compost and the earthworms on metal solubility is explained by their effect on pH and soluble organic carbon and the environmental chemistry of each element.

Earthworms inhabiting arsenic contaminated soils may accelerate the leaching of As into surface and ground waters. We carried out three experiments to determine the impact of passage of As contaminated soil (1150 mg As kg−1) through the gut of the earthworm Lumbricus terrestris on the mobility and speciation of As and the effects of earthworm mucus on As mobility. The concentration of water soluble As in soil increased (from 1.6 to 18 mg kg−1) after passage through the earthworm gut. Casts that were aged for 56 days still contained more than nine times greater water soluble As than bulk earthworm inhabited soil. Changes were due to increases in As(V) mobility, with no change in As(III). Dilute mucus extracts reduced As mobility through the formation of As–amino acid–iron oxide ternary complexes. More concentrated mucus extracts increased As mobility. These changes, together with those due to the passage through the gut, were due to increases in pH, phosphate and soluble organic carbon. The mobilisation of As from contaminated soils in the environment by cast production and mucus secretion may allow for accelerated leaching or uptake into biota which is underestimated when bulk soil samples are analysed and the influence of soil biota ignored.

- by Tom Sizmur
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- Phytoremediation, Arsenic, Bioremediation, Earthworm ecology

ABSTRACT The effects of earthworms Eisenia spp. on microorganisms of three different habitat soil, compost, and vermiculture were studied. Microbial communities of gut and fresh faeces of earthworms and substrates, the worms were collected from, were analysed. Microbial biomass and composition of the total microbial community were examined using phospholipid fatty acid (PLFA) biomarkers. Archaeal and bacterial communities were studied by polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE). The culturing methods were used for assessment of counts, species richness and growth strategy of bacteria.

- by Beto Pashanasi and +2
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- Earthworm ecology, Earthworms, Soil organic matter, Forest Cycle
- by Francois Bastardie
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- Soil ecology, Earthworm ecology

The introduction of earthworms into soils contaminated with metals and metalloids has been suggested to aid restoration practices. Eisenia veneta (epigeic), Lumbricus terrestris (anecic) and Allolobophora chlorotica (endogeic) earthworms were cultivated in columns containing 900 g soil with 1130, 345, 113 and 131 mg kg−1 of As, Cu, Pb and Zn, respectively, for up to 112 days, in parallel with earthworm-free columns. Leachate was produced by pouring water on the soil surface to saturate the soil and generate downflow. Ryegrass was grown on the top of columns to assess metal uptake into biota. Different ecological groups affected metals in the same way by increasing concentrations and free ion activities in leachate, but anecic L. terrestris had the greatest effect by increasing leachate concentrations of As by 267%, Cu by 393%, Pb by 190%, and Zn by 429% compared to earthworm-free columns. Ryegrass grown in earthworm-bearing soil accumulated more metal and the soil microbial community exhibited greater stress. Results are consistent with earthworm enhanced degradation of organic matter leading to release of organically bound elements. The degradation of organic matter also releases organic acids which decrease the soil pH. The earthworms do not appear to carry out a unique process, but increase the rate of a process that is already occurring. The impact of earthworms on metal mobility and availability should therefore be considered when inoculating earthworms into contaminated soils as new pathways to receptors may be created or the flow of metals and metalloids to receptors may be elevated.

- by Tom Sizmur
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- Microbiology, Soil Science, Arsenic, Trace element Geochemistry

The genus Moniligaster Perrier, 1872 is restricted to the Western Ghats mountain regions of the southern Peninsular India. A new species, Moniligaster julkai Narayanan & Paliwal, sp. nov., is described and illustrated using samples found in the Kerala districts of Kottayam and Pathanamthitta. Apart from that, the status of Moniligaster deshayesi minor Michaelsen, 1913 is critically reviewed, and it is upgraded to species rank as Moniligaster minor Michaelsen, 1913, based on a collection made near its type locality. Furthermore, new distributional records for other Moniligaster species are provided. With this discovery, the genus Moniligaster now has a total of 14 recognised species.

- by S Prasanth Narayanan and +1
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- Earthworm ecology, Earthworms, Earthworm Identification, Earthworm taxonomy

While many studies have examined the effects of flooding on earthworm population distributions, few studies have investigated physiological and behavioural responses of earthworms to the low oxygen conditions caused by flooding. An earthworm's skin is its oxygen exchange organ, allowing earthworms to survive in flooded environments provided that the water contains sufficient dissolved oxygen. Individuals of three species of earthworm, the anecic Lumbricus terrestris (Linneaus, 1758), the green morph of the endogeic Allolobophora chlorotica (Savigny, 1826) and the epigeic Lumbricus castaneus (Savigny, 1826) were placed in reconstituted groundwater that was either kept aerated or kept in a sealed container so that dissolved oxygen was gradually consumed as the earthworm respired. Oxygen saturation of the water was measured over time in sacrificial triplicate replicates from each treatment at discrete time points; earthworm mortality and mass were recorded. Before treatments, oxyge...

- by Mark Hodson
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- Soil Science, Earthworm ecology, Flooding, Earthworms
- by Mark Hodson
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- Ecology, Risk assessment, Applied Ecology, Earthworm ecology

The tropical earthwormPontoscolex corethrurus(Rhinodrilidae, Oligochaeta) presents a broad distribution (e.g., 56 countries from four continents). It is generally assumed that temperature appears to limit the success of tropical exotic species in temperate climates. However, the distribution range of this species could advance towards higher elevations (with lower temperatures) where no tropical species currently occur. The aim of this study was to evaluate the soil and climatic variables that could be closely associated with the distribution ofP. corethrurusin four sites along an altitudinal gradient in central Veracruz, Mexico. We predicted that the distribution ofP. corethruruswould be more related to climate variables than edaphic parameters. Five sampling points (in the grassland) were established at each of four sites along an altitudinal gradient: Laguna Verde (LV), La Concepción (LC), Naolinco (NA) and Acatlán (AC) at 11–55, 992–1,025, 1,550–1,619 y 1,772–1,800 masl, respect...

- by A. Ortíz-Ceballos
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- Biology, Invasive species ecology, Invasion Ecology, Biological invasions

Quantitative sampling for earthworms by hand sorting was carried out in different habitats of Sirohi district of Rajasthan. Seasonal changes in population of earthworm species viz. Pontoscolex corethrurus and Octochaetona beatrix were studies in different fields. Population of the earthworm Pontoscolex corethrurus varied in different seasons in agricultural, forest and grasslands. Similarly, the population of Octonochaetona beatrix changed in agricultural, garden and orchard lands. Highest population of Pontoscolex corethrurus was recorded in agricultural land in July, whereas its population was lowest in forest land. The earthworm Octochaetona beatrix was abundant in garden but poor in agricultural land. The highest population of both species was observed in the rainy season but it was meagre in the summer and winter seasons. Both the species of earthworms (Pontoscolex corethrurus, Octochaetona beatrix) showed their population peak twice i.e. one in July-August and another in February-March. Our aim was to understand the effect of seasonal changes on population density of these two earthworms.

- by Suresh Kumar
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- Population Dynamics, Earthworm ecology, Earthworms, Earthworm Sampling
- by Heribert Insam
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- Microbial Ecology, Earthworm ecology, Biological Sciences, Environmental Sciences
- by Shimon Rachmilevitch
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- Forestry, Plant Ecology, Ecology, Agriculture
- by Cécile Villenave
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- Earthworm ecology, Earthworms, Forest succession, Soil organic matter

1. There is little consensus on how agriculture will meet future food demands sustainably. Soils and their biota play a crucial role by mediating ecosystem services that support agricultural productivity. However, a multitude of site-specific environmental factors and management practices interact to affect the ability of soil biota to perform vital functions, confounding the interpretation of results from experimental approaches. Insights can be gained through models which integrate the physiological, biological and ecological mechanisms underpinning soil functions.
2. We present a powerful modelling approach for predicting how agricultural management practices (pesticide applications and tillage practices) affect soil functioning through earthworm populations. By combining energy budgets and individual-based simulation models, and integrating key behavioural and ecological drivers, we accurately predict population responses to pesticide applications in different climatic conditions.
3. We use the model to analyse the ecological consequences of different weed management practices. Our results demonstrate that an important link between agricultural management (herbicide applications and zero, reduced and conventional tillage) and earthworms is the maintenance of soil organic matter (SOM).
4. We show how zero and reduced tillage practices can increase crop yields while preserving natural ecosystem functions. This demonstrates how management practices which aim to sustain agricultural productivity should account for their effects on earthworm populations, as their proliferation stimulates agricultural productivity.
5. Synthesis and Applications. Our results indicate that weed management that relies on tillage has longer term effects on soil biota than pesticide control, if the herbicides have short dissipation times. If pesticides known to be toxic to earthworms are applied, the risk of exposure will be reduced if irrigation is stopped around application time or if application is carried out during dry periods. Similarly, if the organic content of the soil is increased the recovery rate of earthworm populations can be increased. However, effects are not necessarily additive and the impact of different growing practices on earthworms will depend on their timing and the environmental conditions. Our model can be used to estimate the overall impact of different combinations of crop management activities in different regions to explore how earthworm populations respond. If our models are linked to crop yield models the costs and benefits of different crop solutions for both yields and biota could be estimated and aid optimisation of the trade-off between different ecosystem services.

- by Mark Hodson and +1
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- Risk assessment, Earthworm ecology, No tillage, Pesticides

Cattle treading accompanied by a high input of organic matter was previously found to favour methanogenesis
in soils at a site used as winter pasture in outdoor cattle husbandry. In this current study, the
phylogenetic microarray AnaeroChip revealed high methanogenic diversity in a cattle-impacted soil with
predominance of Methanosarcina, and presence of Methanoculleus, Methanobacterium, Methanocalculus,
Methanobrevibacter, Methanosaeta, Methanothermobacter, Methanogenium, Methanohalobium, and Methanolobus.
The bioturbation effects of an epigeic earthworm, Eisenia andrei, on the methanogenic
microbial community in cattle-impacted soil were studied in a 6-month laboratory microcosm experiment.
The microarray showed that the methanogenic community was changed by addition of earthworms
to the soil. The abundance of 16S rRNA Methanosarcina gene copies decreased two fold in soil
with worms compared to soil without worms after 2 months of incubation and decreased three fold after
4 and 6 months of incubation. The biomass of anaerobic microorganisms, as determined by unsubstituted
non-ester-linked phospholipid fatty acid analysis, decreased in soil incubated for 4 and 6 months
with worms. The abundance of the methyl-coenzyme M reductase (mcrA) gene, which is involved in CH4
production and is present in all methanogens, was not, however, changed by worms, and addition of
worms even increased the rate of methane production. This study provides the first data concerning
interactions between earthworms and methanogens in cattle-impacted pasture soil. The results of this
laboratory microcosm experiment indicate that E. andrei changes the composition of the soil methanogenic
community but does not reduce the total abundance of the methanogenic community and
methane production rate.

- by Alica Chronakova and +1
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- Microbial Ecology, Earthworm ecology, Methane, Soil Microbiology

With advent of the nanotechnology era, the environmental risk has continuously been receiving engineered nanomaterials, as well as their derivatives. Our current understanding of the potential impact of nanomaterials and their effect on soil organism is limited. The present study fills the gap between effect of manufactured nanomaterials (NPs) and their available natural scavengers. In the study, earthworm Eisenia fetida (EW), which occupies 60 to 80% of the total biomass and well known for its contribution to cellulolytic degradation of organic wastes, was exposed to ZnO-NPs. Findings suggests that E. fetida can survive even at high exposure of ZnO-NPs (10 mg/kg) and can exhibit increase in bio-accumulation of Zn content in its body tissue with decreased NPs. Exposure of 35 and 10 nm ≥3.5 mg/kg sized NPs showed an increase in cellulase activity by 38 to 41%. This increase in cellulolytic activity in EWs’ gut may also be helpful in the bioconversion of lignocelluloses waste. Eighteen strains of cellulose hydrolytic bacteria capable of producing cellulase were obtained from the guts of EWs exposed to ZnO-NPs. The results of biochemical and 16SrRNA gene sequence examinations showed that six strains belongs to Bacillus sp.; five strains belongs to the sublines of Bacillus and others belongs to the Pseudomonas sp. The study advocates the application of ZnO-NPs enhance gut-associated microbial activity.
Key words: Cellulose hydrolytic bacteria, ZnO-NPs, E.fetida, Gut -flora.

A new apparatus called ‘gamma column’ developed by Capowiez et al. (2001), enables the continuous movements of radio-labelled earthworms to be tracked in artificial soil cores (3D-space). The present study aimed at analysing the patterns of creation and use of burrow systems by earthworms. Each individual was radio-labelled by injecting a small source of 60Co (13μCi) into its coelomic cavity and then incubating them separately in artificial soil cores for 21 days. The continuous movements of earthworms were classified as three kinds of movements (“to dig”; “to move forwards”; “to move backwards”). Break points that defined the limits between these movements were either the inversion of the displacement of the earthworm or the start of a new burrowing phase. Trajectories of the individuals (one of Lumbricus terrestris and one of Nicodrilus giardi) were analysed and qualitative differences were found: L. terrestris built only one vertical burrow in punctuated bouts of activity and, between these short digging events, oscillated many times up and down in its burrow. N. giardi displayed distinct phases of digging, when it built a more complex burrow system with several branches, and phases of use when it oscillated equally from the top to the bottom of the core. Even though it was based on only one observation per species, this preliminary work provides a promising description of the dynamics of burrowing behaviour and tests their hypothetical species-specificity under artificial conditions.

- by Francois Bastardie
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- Earthworm ecology

The aim of this study was to test the impact of compost and biochar, with or without earthworms, on the mobility and availability of metals, and on the growth of grass to re-vegetate contaminated soil from the Parys Mountain mining site, Anglesey. We also determined if the addition of earthworms compromises remediation efforts.In a laboratory experiment, contaminated soil (1343mgCukg−1, 2511mgPbkg−1

- by Tony Hutchings
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- Soil Science, Chemistry, Environmental Remediation, Plant Biology
- by Jérôme Mathieu
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- Biology, Earthworm ecology, Dispersal Ecology, Biological Sciences
- by Václav Pižl
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- Microbial Ecology, Earthworm ecology, Biological Sciences, Environmental Sciences
- by Telmo Amado
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- Ecology, Risk assessment, Applied Ecology, Earthworm ecology