Diversity Of Soil Microarthropods Research Articles

Effect of Application of Vermicompost and Conventional Compost Derived from Different Residues on Pea Crop Production and Soil Faunal Diversity in Agricultural System in Garhwal Himalayas India

Sedentary crop-livestock mixed farming is the predominant agricultural land use in Central Himalaya upland and largely rainfed; agrochemicals are not used at all. Farmers focus on increasing yields with poor soil fertility management practices resulted in sharp decline in production of pea crop in the study site. Therefore in present study options are being looked into devising some conservation strategies that increase yields of pea while reducing harm to soil biodiversity at a local scale here. The present study explores the efficiency of P. excavatus as endemic earthworm species for vermicomposting, the potential utilization of Conventional oak based farmyard manure (FM-O); Conventional pine based farmyard manure(FM-P); Earthworm fed ? Cow dung + oak leaves based vermicompost (VC-O); Earthworm fed ? Cow dung + pine leaves based vermicompost (VC-P); freshly fallen leaf litter (LM) on pea crop productivity and soil faunal diversity in agricultural system, and if the changed soil faunal biodiversity scenario in any way affected the crop production. The higher uptake of nitrogen, higher germination percentage enhanced seedling growth, early emergence flower, increase number of pods, seed, husk , and root biomass was significantly higher in plants which received VC-O followed by VC-P as manure input treatments. The change in the diversity of soil micro arthropods in relation to quality change in organic residues input in experimental plots and expressed as the Simpsons diversity index showed that the diversity of soil fauna is related to improvements in soil conditions resulting from nutrient manipulations through vermicompost and conventional compost treatments. This response of soil biota to increased production most likely represents an increase in the availability of resources through addition of vermicompost when compared to other compost treatments. Alternatively, an increase in predators and therefore predation, could, increase the diversity of its prey, thereby decreasing dominant competitors and reducing the possibility of competitive exclusion, but this needs further studies. Chronosequence study during cropping season indicated that the composition and abundance of soil fauna in agricultural fields changed considerably with time under cultivation. This technology has now been adopted by the farmers in the area once again for growing the pea crop.

Faunalpedturbation effects on soil microarthropods in the Negev Desert

Soil microarthropod communities in seed-harvester ant-nest ( Messor spp.) soils and pits excavated by porcupines ( Hystrix indica) were examined on a hill-slope catena in the Negev Desert to test the hypothesis that animal-produced soil disturbances increase abundance and diversity of soil biota. There were significantly fewer arthropods and lower taxonomic diversity of soil microarthropods at the top and mid-slope locations, with no consistent patterns of abundance between cool-wet and hot-dry seasons. Some prostigmatids, cryptostigmatids, and other arthropods in ant-nest, porcupine-pit, and undisturbed soils were more abundant in wet than dry seasons at some locations but more abundant in the hot-dry season at other locations and sample sites. Seven prostigmatid mite families that were relatively abundant in undisturbed soils were absent or of low abundance in ant-nest modified and porcupine-pit soils at mid- and low-slope catena locations. The data result in rejection of the hypothesis. However, the significant effects of topographic position on the catena on soil microarthropod communities emphasize the importance of examining broad spatial patterns and temporal variation before making generalizations about the effects of ecological engineers on arid ecosystem structure and function.

Soil micro-arthropod communities and microbial parameters in the potato ridge under two field management systems on sandy loams in Atlantic Canada

Intensive forms of soil management occur in potato (Solanum tuberosum L.) production systems, but little is known about the influence of such practices on soil biological properties. Microbial biomass C, phosphatase activity, and the abundance (number), richness (family groups), and diversity of soil micro-arthropods (Collembola and mites) were compared in conventional and adjacent integrated pest management (IPM) systems of 3-yr potato rotations, established on fine sandy loams in Prince Edward Island, Atlantic Canada. The study was conducted at two sites over a 2-yr period. Soil microbial parameters were generally similar between management systems. Management differences showed some effect on micro-arthropod abundance and richness in three of the eight comparisons. Under optimum soil-water conditions, both Collembola and mite communities increased over the growing season regardless of management system. Key words: Soil management for potato, Collembola, mites, soil microbial biomass carbon, acid phosphatase, integrated pest management

Exploring the natural and human-induced effects on the assemblage of soil microarthropod communities in Argentina

In order to determine the independent and joint effects of: (1) crop management; (2) soil condition; and (3) site location on soil biota assemblage, we examined the effects of several crop management and soil condition descriptors on the abundance and diversity of soil microarthropods in crop fields. Data were analyzed using linear regression, canonical correspondence analysis and variance partitioning. Our results indicated that: (1) soil mites was the most affected group by crop management; (2) most of the variance on microarthropod abundance remained unexplained as none of the descriptors were able to explain more than 10% of total species matrix variance; (3) tillage intensity resulted in higher variance explained of the species matrix than pesticide use or crop rotation; (4) soil carbon was the most influential factor among soil condition descriptors; and (5) a significant component of species variation was accounted for by the spatially structured fraction of the explanatory descriptors and other underlying spatial processes. Following the methods proposed in this work, further studies based on the obtained results may increase their power to detect agriculturally induced effects on soil biota by including more soil fauna groups and more controlled environmental factors or by improving the description of the local scale spatial heterogeneity.

Soil Arthropod Responses to Different Patch Types in a Mixed-Conifer Forest of the Sierra Nevada

Abstract The Teakettle Ecosystem Experiment in the southern Sierra Nevada is using thinning and prescribed fire to recreate historical stand conditions. As part of Teakettle we assessed pretreatment diversity and density of the soil arthropod community in 1998 and 2000. We determined the density and diversity of soil microarthropods among treatment plots, the influence of patch type (closed canopy, canopy gaps, Ceanothus sp., and coarse woody debris [CWD]), and established baseline pretreatment data. Mites were the dominant microinvertebrates (78%). Canopy gaps had the lowest mite density and diversity, and were more sensitive to year-to-year changes in climate (1998 was an extremely wet year for the region). Soil organic matter as represented by bulk density appeared to be most closely associated with changes in species composition among different patch types. There was substantial overlap, however, in community composition among the different patch types as represented by nonmetric multidimensional scaling (NMS) ordination. No significant differences were observed for mite species richness and density among plots assigned to future treatments. The gap data suggest that in the characteristically hot, dry summers of the southern Sierra Nevada the rate of recovery of vegetation following thinning and fire treatments may have a significant influence on the recovery rate of microarthropods, not only by providing sources of energy inputs in the form of dead organic matter, but also by moderating the microclimate of the forest floor. FOR. SCI. 51(3):255–265.

Relating microarthropod community structure and diversity to soil fertility manipulations in temperate grassland

We aimed to identify patterns of diversity in a below-ground community of microarthropods (mites and Collembola) after 15 months of a nutrient (calcium and nitrogen) manipulation experiment, located at the Natural Environment Research Council (NERC) Soil Biodiversity Site in Scotland, UK. We found that microarthropod densities increased with elevated soil fertility, but we detected no concurrent change in the diversity of soil microarthropods (mites and Collembola combined). That microarthropod density increased concurrently with improvements in soil fertility and plant productivity suggests that soil microarthropod communities are predominately regulated by bottom-up forces, driven by increased energy transfer via plant inputs to soil, providing increased food resources for fauna. However, that we found no concurrent change in the diversity of soil microarthropods provides little support for the idea that the diversity of soil fauna is positively related to their population density, primary productivity or improvements in soil conditions resulting from nutrient manipulations. However, we did find that microarthropod communities of more fertile sites contained a greater proportion of predators suggesting that more energy was transferred to higher trophic levels under elevated soil fertility. Our findings suggest that unlike plant communities, soil faunal diversity may not be strongly regulated by competition in productive situations, since competitive exclusion might not occur due to increased predation. Whilst we conclude that soil microarthropod diversity at our study site has not been affected by the nutrient additions to date, in the longer term we predict that changes in community composition and diversity could arise, most likely through top-down regulation of the soil food web.

Responses of soil microarthropods to experimental short-term manipulations of soil moisture

In this study we experimentally manipulated the precipitation pattern (frequency and intensity) in a Mediterranean pine forest on Mt. Holomon (northern Greece) in order to investigate the response of soil microarthropods (Collembola and oribatid mites). Our experimental treatments included drought, frequent and infrequent irrigation and lasted for 4 months. The treatments affected soil water content, maximum soil temperature and diversity of soil microarthropods. Compared to the undisturbed surrounding area, drought decreased soil water content as well as microarthropod species richness and increased maximum soil temperature. Irrigation treatments increased soil water content and microarthropod species richness. Infrequent irrigation increased maximum soil temperature. Oribatid mites and Collembola responded differently to the irrigation treatments. The collembolan community showed higher species evenness and diversity in the frequently irrigated plots and the oribatid mite community in the infrequently irrigated ones. Our results indicate that irrigation pattern (and the corresponding changes in soil moisture) will have an impact on soil ecosystems in complicated non-linear ways.

Oribatid mite and collembolan diversity, density and community structure in a moder beech forest ( Fagus sylvatica): effects of mechanical perturbations

The effects of mechanical perturbations on two soil microarthropod communities (oribatid mites and collembolans) were investigated in a moder beech forest on sandstone. We disturbed the soil matrix by sieving and mixing the litter and soil of the moder profile. The top litter layer (L material) and the deep mineral soil (Bv) remained intact. Three amounts of disturbance were established: a single perturbation, perturbations once every 2 months (60 d) and once every 2 weeks (14 d). Densities of most groups of oribatid mites and all groups of collembolans declined in the disturbance treatments. In most cases, densities were lowest in the strong perturbation treatment (14 d). Desmonomata were the only group of oribatid mites that benefited from intermediate amounts of disturbance but not from the strongest disturbance. Also, disturbances reduced diversity of oribatid mites and collembolans. According to their sensitivity to disturbances oribatid mites ranked Poronota=Enarthronota=Suctobelbidae (the most sensitive)>Oppiidae> Tectocepheus>Desmonomata. The ranking of collembolans was Folsomia (the most sensitive)>Hypogastruridae/Neanuridae>Onychiuridae=Isotomidae>Entomobryidae. Generally, tolerance of disturbance was wider for oribatid mites than for collembolans. The results indicate that disturbances such as mixing of litter and soil and comminution of litter material strongly affect the density and diversity of soil microarthropods. However, they also indicate that the soil microarthropod community is resistant to weaker disturbances. In the field, mechanical disturbances are often caused by burrowing of earthworms. Our results suggest that the high density of microarthropods in moder soils may be due to the low intensities of mechanical disturbances by earthworms.

Changes in abundance and diversity of microarthropods associated with Fescue Prairie grazing regimes

Summary Livestock grazing influences plant community structure, soil quality and health, and is likely to also affect the populations and diversity of soil biota. In our study, we determined the abundance and family level diversity of soil mites under very heavy and light grazing regimes, and a very heavy grazing exclosure, and asked whether there were differences in abundance of mite taxa that reflected the severity of disturbance. The field experiment we sampled was established in 1949 on a Rough Fescue Prairie with Orthic Black Chernozemic (Udic Haploboroll) soils near Stavely Alberta Canada. Soil cores were taken from the light (L)(1.2 AUM (animal unit month) ha –1 ) and very heavy (VH) (4.8 AUM ha –1 ) grazing regimes and the grazing recovery exclosure (Ex) in the very heavy grazing site in June and October 1999. The results showed that the soil temperature, moisture and bulk density varied between the grazing regimes, soil depth and the sampling times. Collembola were not abundant at any of the sites compared with Acari. Among Acari, prostigmatid mites were significantly more abundant in VH site and all the grazing treatments at both depths and sampling times. Oribatida, and to a lesser extent Mesostigmata, were more closely associated with reduced and undisturbed habitats than the Prostigmata, and there was a positive relationship between increased grassland productivity and the abundance and diversity of soil microarthropods. Our results suggest that Acari are sensitive to soil disturbance.

Pollution‐induced community tolerance and functional redundancy in a decomposer food web in metal‐stressed soil

Pollution may lead to the development of pollution-induced community tolerance (PICT) in a stressed community. We studied the presence of PICT in soil food webs using soil microcosms. Soil microcosms containing soil invertebrates and microbes were collected from polluted and unpolluted areas and exposed to a range of soil zinc concentrations. A pine seedling was planted in each microcosm to measure the effects of the origin of the community and Zn pollution on above-ground plant production. The effects of the treatments on nutrient content in the soil were also measured. The diversity of soil microarthropods and the soil's mineral nutrient content were low at the Zn-polluted site. We did not observe an increasing Zn tolerance among the soil organisms in the polluted soil. However, low population growth rates of soil invertebrates from the polluted site may indicate the deleterious effects on fitness of long-lasting pollution. In the soil from the nonpolluted site, Zn additions caused changes in the invertebrate food web structure. These changes were explained by the good physiological condition of the animals and their insensitivity to Zn. The fact that the food web structure in soil from the polluted site did not change can be used as a rough indicator of PICT. Structural stability is presumed by the lack of Zn-sensitive species at this site and the inability of populations to acclimate by altering their growth or reproduction patterns in response to changing soil conditions. Although microbial-based soil decomposer systems may have a high functional redundancy, our results indicate that metal stress at the polluted site exceeds the tolerance limits of the system. As a consequence, ecosystem function at this site is endangered. This study also shows that the evolution of metal tolerance by soil decomposer organisms may not be a common reaction to soil pollution, although changes of population and community structure indicated severe metal stress on organisms.

Intraspecific aggregation, `probability niches' and the diversity of soil microarthropod assemblages

Investigations of the structure, distribution and abundance of soil faunal communities have demonstrated three notable points. They are very diverse in numbers of species, highly spatially aggregated and appear to exhibit a low degree of food resource specialisation. In temperate regions these observations appear to be expressed to their greatest extent among the microarthropod assemblages of highly organic woodland soils. The species diversity of oribatid mites (Cryptostigmata: Acarina) in such environments can be bewildering and remains to be reconciled satisfactorily with classical Hutchinsonian niche theory. In this study the Shorrocks model is applied to a `fungivorous guild' composed of oppiid mites. The results indicate an aggregated pattern of oribatid distribution and abundance which may contribute to understanding the extraordinary diversity of soil microarthropods in temperate woodland soils. The datasets show that independent intraspecific aggregation of competing oppiid species over patches, alone, might be sufficient to stabilise coexistence and facilitate the high species diversity in this guild.

Distribution and diversity patterns of soil mites and other microarthropods in a Chihuahuan desert site

This paper reports the results of a pilot survey of the patterns of distribution and species diversity of soil microarthropods from 12 different sites in a Chihuahuan Desert watershed in southern New Mexico. A total of 18 orders of arthropods was recorded from 49 samples, distributed across this watershed. Mites and Collembola predominated throughout. Mites were more abundant than Collembola in all sites except in Prosopis litter from the edge of a playa. At this site, collembolan density was estimated to be 24,460/m 2 . Four orders of mites occurred in the sites surveyed: Prostigmata, Cryptostigmata, Mesostigmata and Astigmata. The last-named group was so infrequent that it was not considered further. The Mesostigmata were numerous only in Atriplex litter. Prostigmata and Cryptostigmata were equally abundant at only two sites: the litter under Prosopis on the bajada site and the mineral soil under Fallugia. Elsewhere, Cryptostigmata tended to be more numerous than Prostigmata where the organic content of the substratum was high (> 30%) and vice versa. The highest total mite density occurred in the Juniperus litter (29, 486/m 2 ), the lowest in Larrea litter (8274/m 2 ). These estimates are considerably higher than those recorded from a Juniperus site in the more arid Mojave Desert, but they are much lower than densities considered typical of cool, moist temperate deciduous forests. The densities of Prostigmata and Mesostigmata compare favourably with those reported from sites with similar rainfall in Australia. Cryptostigmatid densities are much higher in the Chihuahuan sites, however. An Index of Diversity, calculated for the various groups of microarthropods at the 12 sites, was very variable, but values approximating to those reported for the microarthropod fauna of an English beech woodland were obtained for several sites. The equitability component of this species diversity provided a good indicator of the relative stability of the sites studied.

Forest leaf litter decomposition in the vicinity of a zinc smelter

Concentrations of about 26,000 ppm Zn, 10,000 ppm Fe, 2,300 ppm Pb, 900 ppm Cd, 340 ppm Cu, and 0.40% S were measured in the O2 litter horizon about 1 km from a zinc smelter at Palmerton, Pennsylvania. Samples taken about 6 km east of the smelter had concentrations of about 15,000 ppm Zn, 6,500 ppm Fe, 970 ppm Pb, 250 ppm Cd, 170 ppm Cu, and 0.26% S. Samples from a control area about 40 km east of the smelter had concentrations of 2,800 ppm Fe, 650 ppm Zn, 260 ppm Pb, 50 ppm Cu, 9 ppm Cd, and 0.13% S.Litter bags were used to estimate first-year weight loss in sassafras leaves and a mixture of chestnut oak/red oak leaves in the three sites. At the end of one year, average weight loss for sassafras was 39.3% in the control site, 21.8% at 6 km, and 17.5% at the 1 km site. For the chestnut oak/red oak mixture, average weight loss was 36.8% (40 km), 25.7% (6 km), and 19.1% (1 km). Numbers and diversity of soil microarthropods inhabiting the litter bags showed a corresponding decline at sites near the smelter. Concentrations of Ca, Cd, Cr, Cu, Fe, Mg, Mn, N, Na, Ni, P, Pb, S and Zn in the decomposing litter were also measured.The average amount of organic matter on the forest floor was estimated to be 3.8 kg/m2 in the control site, about 3.8 kg/m2 at 6 km, and about 8.1 kg/m2 1 km from the smelter. Average thickness of the litter horizons in these three sites was 6.0 cm (40 km), 7.0 cm (6 km), and 12.4 cm (1 km), suggesting a long-term depression of decomposition and mineral cycling near the smelter.