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1.
In south-eastern Australia, strips of planted native trees and shrubs (shelterbelts) are frequently established to restore ecosystem services altered by agriculture. Despite their wide use, little is known about the effects of establishing shelterbelts on soil macro invertebrates, especially earthworms, which are of major importance in soil processes. We assessed earthworm composition, diversity and biomass in three land use systems: native shelterbelts dominated by Acacia and Eucalyptus species, agricultural pastures and native remnant woodland fragments dominated by Eucalyptus blakelyi and/or Eucalyptus melliodora. Earthworm communities differed significantly among systems, with abundance, biomass and diversity greatest under pasture. Within shelterbelts we saw a shift from high earthworm biomass and density to low with increasing time after establishment. Soil edaphic variables did not correlate strongly with earthworm biomass or density, but were correlated with earthworm community composition. Overall the introduction of native woody vegetation was associated with a decline in density and biomass of earthworms, including a decrease in the relative abundance of exotic species. As such shelterbelts can be used to promote native earthworm relative abundance, which may be important for local diversity, soil function and landscape connectivity.  相似文献   

2.
The conversion of single-species coniferous forest stands into mixed stands by promoting the natural regeneration of indigenous broadleaved tree species was studied in a forest-heathland on the Veluwe, in the central part of the Netherlands. Red deer (Cervus elaphus), roe deer (Capreolus capreolus) and wild boar (Sus scrofa) had a large impact on regeneration dynamics, as was established by comparing 20 pairs of fenced and unfenced plots (40 × 40 m) during a 10-year period. A fivefold reduction of total herbivore biomass to 500 kg per km2, resulted in a strong increase of shrub and tree sapling numbers in all vegetation types. However, height growth of the most palatable broadleaved tree species was still strongly impeded. Under the present-day grazing pressure, Scots pine (Pinus sylvestris) and beech (Fagus sylvatica) will become the dominant canopy species in the forests in the near future. It is argued that the most browse-sensitive woody species such as pedunculate and sessile oak (Quercus robur and Q. petraea) will successfully regenerate, only if temporal and spatial variation in browsing pressure is allowed to occur.  相似文献   

3.
In sloping oak forests of the German low mountain range high wild boar (Sus scrofa) and red deer (Cervus elaphus) population densities may affect soil ecological processes by grubbing, grazing, trampling and dunging. We simulated wild boar grubbing in a fenced exclosure and an unfenced replicate and established two adjacent control plots, one fenced, the other unfenced. We evaluated if repeated soil bioturbation and game exclusion by fencing influence soil texture, soil chemical and soil biotic properties in the upper soil over a time period of 2 years. Soil bioturbation was conducted in November 2000 and 2001 creating a grubbing pattern similar to that found in naturally grubbed areas. Soil and fauna sampling was performed in spring and fall of the years 2001 and 2002.Soil bioturbation did not affect soil texture, pH and the contents of organic carbon and nitrogen. In contrast, the contents of potassium and magnesium, the microbial activity and the abundance of saprophageous and predatory soil arthropods were generally lower in grubbed plots compared to ungrubbed control plots (p≤0.05).The exclusion of game did not improve soil quality. On the contrary, microbial activity and the contents of organic carbon and total nitrogen were elevated outside the fenced exclosure (p≤0.05) which may be related to the deposition of urine and dung.Our study found that large mammals affect soil nutrient cycling in sloping oak forests either directly by the deposition of urine and dung or indirectly by accelerating nutrient leaching and disturbing the decomposer system in the soils.  相似文献   

4.
Digging and hand-sorting of soil blocks is a very widespread method in the study of earthworm communities. One disadvantage of this method is that it is very time consuming and often many earthworms are incomplete because they were cut by the digging tools. When authors report earthworm biomass, no mention is made of the assessment of any relationship between the mass of those cut earthworms and their overall weight. In such cases, biomass is generally underestimated. In this paper, our objective was to propose a new method to estimate the weight of incomplete earthworms on the basis of preclitellar diameter and its usefulness for studying the dynamics of earthworm populations. Complete earthworms were collected from samplings performed in native savannahs and man-made pastures of the eastern plains of Colombia and from a poplar grove (Populus sp.) in Central Spain. A strong correlation between the preserved fresh weight and the maximum preclitellar diameter was found for all the species studied. Three types of models have provided a convenient method to estimate earthworm biomass: (i) linear for almost all the species; (ii) exponential for a large Neotropical anecic species, Martiodrilus carimaguensis (Glossoscolecidae); and (iii) second degree polynomic equation.  相似文献   

5.
Microbial biomass is an important source of soil organic matter, which plays crucial roles in the maintenance of soil fertility and food security. However, the mineralization and transformation of microbial biomass by the dominant soil macrofauna earthworms are still unclear. We performed feeding trials with the geophagous earthworm Metaphire guillelmi using 14C-labelled bacteria (Escherichia coli and Bacillus megaterium) cells, fungal (Penicillium chrysogenum) cells, protein, peptidoglycan, and chitin. The mineralization rate of the microbial cells and cell components was significantly 1.2–4.0-fold higher in soil with the presence of M. guillelmi for seven days than in earthworm-free soil and 1–11-fold higher than in fresh earthworm cast material. When the earthworms were removed from the soil, the mineralization of the residual carbon of the microbial biomass was significantly lower than that in the earthworm-free soil, indicating that M. guillelmi affects the mineralization of the biomass in soil in two aspects: first stimulation and then reduction, which were attributed to the passage of the microbial biomass through the earthworm gut, and that the microorganisms in the cast could play only minor roles in the stimulated mineralization and residual stabilization of microbial biomass. Large amounts (8–29%) of radiolabel of the tested microbial biomass were assimilated in the earthworm tissue. Accumulation of fungal cells (11%) and cell wall component chitin (29%) in the tissue was significantly higher than that of bacterial cells (8%) and cell wall component peptidoglycan (15%). Feeding trails with 14C-lablled microbial cells and cell components provided direct evidence that microbial biomass is a food source for geophagous earthworm and fungal biomass is likely a more important food source for earthworms than bacterial biomass. Findings of this study have important implications for the roles of geophagous earthworms in the fate of microbial biomass in soil.  相似文献   

6.
To monitor the effects of liming on forest ecosystems, experimental plots were installed in forests in mid-western Germany. In addition to soil chemical indices, earthworm communities were investigated on these plots about 15 years after first lime applications took place. As a “natural reference”, communities were compared to earthworm records that derived from a beech forest on limestone. In the non-acidified plots that had never been limed only epigeic earthworms were detected in small numbers and low species richness. Forest liming caused higher pH and a higher base saturation in the mineral topsoils. To a large extent, epigeic earthworm species seemed to benefit from this and had increased in number and biomass at all three different locations selected for the investigations. The epigeic dominated communities were completed by anecic Lumbricus terrestris that was rarely found in some of the samples from one location and a number of endogeic species that showed a very patchy distribution in limed plots. In contrast to this, the soil of the beech forest on limestone showed a different community composition. It was dominated by endogeic species in abundance and by anecic species in biomass. On limestone the total biomass of earthworms clearly exceeded the biomass values from all other plots. In conclusion, a long-term support of forest earthworm fauna due to liming was detected. This support was mainly effective for epigeic species, but in some cases for endogeic and anecic species, too.  相似文献   

7.
Influence of orchard soil management on lumbricids, especially Lumbricus terrestris L. In a long-term soil management experiment (apple orchard treated with cultivation methods such as grass mulch, grass harvest, straw mulch, clean cultivation) 6 plots were selected in order to study the abundance and biomass of earthworm populations. The following results were obtained: In all treatments with the exception of straw mulch L. terrestris represented the majority (60.5% on average) of the lumbricid population. Their share in the biomass amounted to 93.3%. The earthworm biomass was the highest in grass mulch; a close correlation was observed between the litter production (grass and leaves) and the biomass of L. terrestris. Added farm yard-manure on plots with grass mulch had no additional positive effect on earthworms. Although a higher earthworm biomass was found under grass mulch in comparison with straw mulch, the species diversity was higher in the latter. Clean cultivation had a highly detrimental effect on all earthworms, especially on the horizontally burrowing species. The annual nitrogen turnover by L. terrestris in mulched orchards was estimated to approx. 50 kg N/ha.  相似文献   

8.
Short rotation forestry (SRF) which consists of planting rapidly growing native and non-native tree species has been introduced to the UK to increase woody biomass production. A largely unknown aspect of SRF species is their interaction with soil fauna, of which the earthworm community is a major component. Earthworms have a pronounced impact on litter decomposition, nutrient cycling and tree growth. Conversely, tree litter and root chemistry can impact on the associated earthworm community development. The aim of this study was to determine direct interactions between SRF species and earthworms. A field-based mesocosm experiment was conducted using Betula pendula (birch) and Eucalyptus nitens (eucalyptus) with two earthworm species Lumbricus terrestris and Allolobophora chlorotica. The one year experiment revealed that native birch and non-native eucalyptus had a similar influence on L. terrestris population development. However, birch had a positive impact on A. chlorotica population establishment compared with eucalyptus. In the presence of earthworms, total tree biomass and leaf nitrogen concentration of eucalyptus were increased respectively by 25% and 27% compared with an earthworm-free control. In the presence of earthworms, surface litter incorporation was greater for both tree species (almost 5 times for birch and 3 times for eucalyptus) compared with controls. This work showed direct SRF-earthworm interactions which differed for tree species.  相似文献   

9.
It is well known that organic matter in the form of dung is utilised as a food source by some earthworms, but little has been reported on the preferences of earthworms for different types of dung in agricultural settings. An experiment was carried out in spring in south-eastern Australia to evaluate the effect that dung from different livestock has on the abundance of earthworms in a grassland environment. We were particularly interested to compare the responses of native Australian earthworms (Megascolecidae) with those of exotic earthworms (Lumbricidae and Acanthodrilidae). The attractiveness of dung from sheep, cattle and horses was measured by determining the abundance and biomass of the resident earthworm species under each dung type at varying times after adding the dung to the soil surface (0, 10, 20 and 30 days). The earthworm population consisted of three exotic species, Apporrectodea trapezoides, Microscolex dubius and M. phosphoreus, and two native species, Spenceriella macleayi and S. bywongensis. Both the number of days that the dung was available to earthworms and the type of dung influenced the numbers and biomass of the earthworms found beneath the dung pats. Significant interactions existed between time and dung type when all adult earthworms were considered as one group and also when adults were split into individual species. The various species responded differently to the dung, but horse dung was generally the more preferred dung type. The significance of these results is discussed in terms of the management of dung in an Australian pastoral context.  相似文献   

10.
Land-use changes can drastically alter earthworm communities. Native species are often lost and few exotic species, such as Pontoscolex corethrurus, rapidly prevail when tropical forests are converted to pastures. However, this process can be reversed when forests recover from abandoned pastures through secondary succession. We hypothesized (1) that the formation of forest floor mass during secondary succession in pastures promotes the recovery of native, anecic earthworms and (2) that the shift from grass vegetation in pastures to woody plants in secondary forests decreases the abundance and biomass of the exotic, endogeic P. corethrurus. To test the first hypothesis, we developed a litter manipulation experiment by removing and adding plant litter in plots of mature secondary forests in the Cayey Mountains, Puerto Rico. To test the second hypothesis we performed a greenhouse experiment to examine the influence of a pasture grass species Axonopus compressus and a dominating woody species Miconia prasina of the secondary forests on the number and biomass of the earthworm P. corethrurus. We found in the litter manipulation experiment that earthworm diversity, density and fresh weight were not affected by litter input. However, in the greenhouse experiment, A. compressus increased the number and biomass of P. corethrurus, whereas M. prasina decreased the exotic, endogeic earthworm. Our results suggest that the quantity of litter does not promote rapid changes (<1 year) in native, anecic earthworm diversity, and that the exotic, endogeic P. corethrurus is favored by grass A. compressus compared to the woody plant M. prasina. The shift in vegetation from grass to woody plants promotes the decrease in the density and biomass of the exotic, endogeic P. corethrurus during secondary succession in old tropical pastures.  相似文献   

11.
Earthworm relationships with vegetation have received extensive attention, and earthworm density has been shown to be related to vegetation types or plant species. However, the factors involved are rarely known. In Congo, we studied the effect of Chromolaena odorata (L) R.M. King & H. Robinson, which invades eucalypt plantations, on soil invertebrates, especially earthworms. In order to investigate relationships between vegetation cover and soil invertebrates, four understory species, including C. odorata, were studied. Also, comparisons were made between plots invaded by C. odorata and plots free from it. The addition of leaf litter on experimental plots was made in order to check its influence. Plant remains were observed in the digestive tract of earthworms. An increased earthworm density was observed under C. odorata. The leaf litter and roots of this species had low lignin/N ratio. The size of leaf fragments found in the digestive tract of the earthworms, and the lack of short-term effect of experimentally added leaf litter, suggested that litter quality could influence earthworm through their feeding on fine particulate top soil organic matter. The amount of soil aggregates, in the size classes that fitted the size range of earthworm casts, was increased under C. odorata. More field experiments are needed to establish a causal effect in the relationships observed between earthworm density and C. odorata. If so, the major drawbacks, such as water and nutrient competition, resulting from C. odorata overrunning the plantations, could be somewhat offset by its positive effects through soil improvement.  相似文献   

12.
Summary Decomposition of garden refuse was studied in containers with and without the earthworm species Eisenia andrei and Lumbricus rubellus. The reduction of cellulose and hemicellulose was greater where earthworms were present. Respiration was similar regardless of the presence of earthworms, whereas dry matter reduction, on average, was greatest without earthworms. The earthworm biomass decreased during the 58 days of the experiment; E. andrei increased in biomass, whereas L. rubellus died out.  相似文献   

13.
To assess the impact of different types of soil tillage on the density, biomass, and community composition of earthworms, a long-term field study was performed in which soils were tilled in different ways for ten years. This study included five different types of tillage: (i) plough, (ii) grubber, (iii) disc harrow, (iv) mulch sowing, and (v) direct sowing. At the end of the experiment the earthworm density, biomass, and community composition, and the SOC (soil organic carbon) content were determined. The results show that density, biomass, and community composition of earthworm populations varied in relation to the type of soil tillage used. The density of anecic earthworm species decreased when soils were managed by conventional ploughing, relative to reduced tillage practices, whereas conversely the density of endogeic species increased. Additionally, the varying types of soil tillage influenced the abundance and biomass of different earthworm species in different ways. The density of Aporrectodea caliginosa was positively influenced by ploughing, whereas Aporrectodea longa, Lumbricus castaneus, and Satchellius mammalis showed a positive relationship to the grubber and Allolobophora chlorotica to direct sowing. We attribute these changes to modifications in the vertical distribution of SOC and varying potentials for mechanical damage of earthworms by tillage. A decrease in tillage intensity modified the vertical SOC distribution in the topsoil and consequently revealed positive effects on earthworm biodiversity, thus sustaining soil functioning.  相似文献   

14.
This study investigated the possibility of a facilitative relationship between Chinese privet (Ligustrum sinense) and exotic earthworms, in the southeastern region of the USA. Earthworms and selected soil properties were sampled five years after experimental removal of privet from flood plain forests of the Georgia Piedmont region. The earthworm communities and soil properties were compared between sites with privet, privet removal sites, and reference sites where privet had never established. Results showed that introduced European earthworms (Aporrectodea caliginosa, Lumbricus rubellus, and Octolasion tyrtaeum) were more prevalent under privet cover, and privet removal reduced their relative abundance (from >90% to ∼70%) in the community. Conversely, the relative abundance of native species (Diplocardia michaelsenii) increased fourfold with privet removal and was highest in reference sites. Soils under privet were characterized by significantly higher pH relative to reference plots and privet removal facilitated a significant reduction in pH. These results suggest that privet-mediated effects on soil pH may confer a competitive advantage to European lumbricid earthworms. Furthermore, removal of the invasive shrub appears to reverse the changes in soil pH, and may allow for recovery of native earthworm fauna.  相似文献   

15.
A field experiment was conducted to study the effects of peat amendment and crop production system on earthworms. The experiment was established on a field previously cultivated with oats and with silt as the main soil type. Perennial crops strawberry, timothy and caraway, and annual crops rye, turnip rape, buckwheat, onion and fiddleneck were cultivated with conventional methods. All the crops were grown with and without soil amendment with peat. Earthworms were sampled twice: 4 and 28 months after establishment of the experiment. In the former case part of the experimental plots were soil sampled and hand sorted for estimation of earthworms. In the latter case all experimental plots were sampled and both soil sampling and mustard extraction was carried out. Soil organic carbon and microbial biomass was measured at 14 and 28 months. Peat increased the abundance of juvenile Aporrectodea caliginosa by 74% in three growing seasons, but had no effect on adult numbers. Lumbricus terrestris numbers were not increased by peat treatment. Three season cultivation of caraway favoured both A. caliginosa and L. terrestris. An equal abundance of A. caliginosa was also found in plots cultivated with turnip rape and fiddleneck. Total earthworm and especially A. caliginosa numbers were very small in plastic-mulched strawberry beds. This was mainly attributed to repeated use of the insecticide endosulfan. With the strawberry plots omitted there was a significant correlation between soil microbial N measured at 14 months and juvenile Aporrectodea spp. and Lumbricus spp. numbers measured at 28 months. Adult earthworm numbers were not associated with either soil organic C or microbial biomass.  相似文献   

16.
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.  相似文献   

17.
We studied the effects of applications of traditionally composted farmyard manure (FYM) and two types of biodynamically composted FYM over 9 years on soil chemical properties, microbial biomass and respiration, dehydrogenase and saccharase activities, decomposition rates and root production under grass-clover, activity and biomass of earthworms under wheat, and yields in a grass-clover, potatoes, winter wheat, field beans, spring wheat, winter rye crop rotation. The experiment was conducted near Bonn, on a Fluvisol using a randomised complete block design (n=6). Our results showed that plots which received either prepared or non-prepared FYM (30 Mg ha–1 year–1) had significantly increased soil pH, P and K concentrations, microbial biomass, dehydrogenase activity, decomposition (cotton strips), earthworm cast production and altered earthworm community composition than plots without FYM application. Application of FYM did not affect the soil C/N ratio, root length density, saccharase activity, microbial basal respiration, metabolic quotient and crop yields. The biodynamic preparation of FYM with fermented residues of six plant species (6 g Mg–1 FYM) significantly decreased soil microbial basal respiration and metabolic quotient compared to non-prepared FYM or FYM prepared with only Achillea. The biodynamic preparation did not affect soil microbial biomass, dehydrogenase activity and decomposition during 62 days. However, after 100 days, decomposition was significantly faster in plots which received completely prepared FYM than in plots which received no FYM, FYM without preparations or FYM with the Achillea preparation. Furthermore, the application of completely prepared FYM led to significantly higher biomass and abundance of endogeic or anecic earthworms than in plots where non-prepared FYM was applied.  相似文献   

18.
Earthworm populations were studied in three tropical agroecosystems of southern Mexico: improved maize with a Mucuna pruriens cover crop (MM), continuous conventional maize (CM) and pastures (P). Three replicates and six monoliths were sampled in each agroecosystem. Three earthworm species were found, two native (Balanteodrilus pearsei, Larsonidrilus orbiculatus) and one exotic (Polypheretima elongata). In all systems, the dominant species was B. pearsei, with negligible presence of the exotic species in MM and P plots. Total abundance was significantly higher in MM than in CM; and earthworm biomass was also higher in MM than in CM and P. Juveniles of both native species dominated, mainly concentrated in the top 20 cm of soil. B. pearsei and L. orbiculatus displayed different preferences (within each agroecosystem) for soil organic matter, N and temperature. Further experiments are required to investigate whether mulching with M. pruriens results in an increased earthworm abundance and biomass through a N-improvement effect or as a result of microclimatic changes and to study the extent to which earthworms and M. pruriens are synergistic in enhancing maize growth.  相似文献   

19.
Food quality influences not only the size of earthworm populations but also their growth and reproduction rates. Here we studied the effect of C to N ratio of pig slurry in microbial biomass and activity and in the growth and reproduction of the earthworm Eisenia fetida. We set up a batch of twelve vermireactors, six each for low (11) and high C to N ratio (19) of pig slurry applied; three of each without earthworms (control) and three containing 500 mature earthworms (E. fetida). After 36 weeks C to N ratio significantly affected earthworm numbers (sevenfold greater in high C to N ratio) and population structure. Thus, in the low C to N ratio treatment the population was composed mainly by mature earthworms (60%), with a higher mean weight than in the high C to N treatment. However, in the high C to N ratio treatment, the population was composed mainly by juvenile and hatchling earthworms (70%). A rapid depletion of dissolved organic C (DOC) content was observed in all treatments. Although earthworms produced an increase in microbial biomass and activity in young modules, finally a decrease in older modules was recorded. The decrease in available carbon did not seem to affect the relationships established between earthworms and microflora.  相似文献   

20.
Biological invasions are one of the most significant global-scale problems caused by human activities. Earthworms function as ecosystem engineers in soil ecosystems because their feeding and burrowing activities fundamentally change the physical and biological characteristics of the soils they inhabit. As a result of this “engineering,” earthworm invasions can have significant effects on soil physical, chemical and biological properties. The species Amynthas agrestis (family Megascolecidae) was introduced to the United States from Asia, and has expanded its distribution range to include relatively undisturbed forests. Here, to clarify life history traits, we reared individuals under seven different conditions of food provision using litter, fragmented litter and soil, and also analyzed the stable isotope ratios of field-collected specimens to investigate their food resources in the field. Second, we examined whether prescribed fire can be used to manage invasive earthworms. We constructed eight experimental plots, each with 100 individuals of A. agrestis each, and burned half of the plots. The feeding experiment showed that the earthworms in units containing soil and some form of organic matter (litter and/or fragmented litter) produced many cocoons, indicating that litter and fragmented litter are important food resources for them. Stable isotope analyses also supported this result. During the experimental fires, average soil temperature at 5 cm depth increased by only 7.7 °C (average maximum of 32.2 °C). Litter mass was significantly reduced by the fires. Although numbers of A. agrestis and cocoons recovered from burned and unburned plots were not different, the viability of cocoons was significantly lower in burned plots. Fire may also reduce the survival rate of juveniles in the next year by depriving them of their preferred food resource. Most native earthworms in the United States live in the soil, while many invasive ones live in the litter layer and soil surface. Therefore, prescribed fire could be a viable tool for control of invasive earthworms without negatively impacting native earthworm populations.  相似文献   

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