Molecular and morphological analyses of faeces to investigate the diet of earthworm predators: Example of a carnivorous land snail endemic to New Zealand     

Stephane Boyer  Gregor W. Yeates  Steve D. Wratten  Andrew Holyoake  Robert H. Cruickshank 《Pedobiologia》2011

Ecosystem services provided by earthworms include increasing soil fertility, recycling organic material and provision of food for numerous predatory species. Estimating the role of earthworms in food webs is essential for a thorough evaluation of the ecosystem services they provide. Although their soft bodies are rapidly digested, earthworm remains can be detected via their chaetae in the faeces of predators.This study proposes a method for the identification of predated earthworm species using only predator faeces. We conducted morphological and molecular analyses of earthworm remains in the faeces of a highly endangered carnivorous land snail (Powelliphanta augusta) endemic to a restricted area of New Zealand.Microscopic examination of faecal strings from P. augusta showed the presence of earthworm chaetae in 47 of the 49 strings examined, suggesting an important role for earthworms in snail diets. Although earthworm tissue was not detectable in snail faeces, earthworm DNA was still present in sufficient quantity for molecular identification. Results showed that this land snail feeds on at least five species of New Zealand endemic earthworms.The method developed here is particularly appropriate for investigating the diet of potential invertebrate and vertebrate predators for which feeding behaviour is difficult to observe and gut content analysis is not possible. Such studies can help to develop a more complete understanding of the ecosystem services provided by earthworm communities. In this case it also helps the conservation of a rare and endangered predatory snail species.  相似文献   

Occurrence and distribution of earthworms in agricultural landscapes across Europe with regard to testing for responses to plant protection products     

Axel Dinter  Christian Oberwalder  Patrick Kabouw  Mike Coulson  Gregor Ernst  Thorsten Leicher  Mark Miles  Gabe Weyman  Olaf Klein 《Journal of Soils and Sediments》2013,13(2):278-293

Purpose

Within the regulatory framework for authorisation of plant protection products (PPPs) (EU Directive 91/414/1991/EEC replaced by Regulation (EC) 1107/2009), higher tier risk assessments and earthworm field tests are conducted in different countries across Europe. This paper describes dominant earthworm species for regulatory and biogeographical regions in agricultural landscapes across Europe and examines regional differences in earthworm communities and densities and their respective response to a toxic reference.

Materials and methods

For the assessment of earthworm abundance and species distribution, data of untreated control plots from 30 earthworm field studies were analysed; each conducted according to the ISO 11268–3 (1999) guideline by European Crop Protection Association member companies in the context of registration of PPPs. For the evaluation of the response to PPPs under different regional and climatic conditions, the effect on earthworm abundance was assessed by comparing plots treated with toxic references with untreated control plots. Additionally, a comparative literature review was included providing an overview of earthworm species composition and densities in agricultural crops from 14 European countries.

Results and discussion

The assessment of earthworm field studies from six different European countries revealed that common earthworm species of anecic and endogeic ecological groups are present at most field sites. Dominant species groups of endogeic and anecic earthworms can be defined that are abundant in all assessed countries. These are the endogeic species Aporrectodea caliginosa, Aporrectodea rosea and Allolobophora chlorotica, and the anecic species Lumbricus terrestris (Northern and Central Europe) and Lumbricus friendi (Southern Europe). Taking into account the high variability in total earthworm abundances, it can be concluded that the variability within regions was larger than the variability between regions.

Conclusions

Analysis of the earthworm community and data of toxic references lead to the conclusion that testing in different zones is not considered necessary.  相似文献   

Quantifying key parameters related to the life cycle of Caligus rogercresseyi     

Jaewoon Jeong  Gregor F. McEwan  Gabriel Arriagada  Cristian Gallardo-Escrate  Crawford W. Revie 《Journal of fish diseases》2022,45(1):219-224

The salmon louse Caligus rogercresseyi (Boxshall and Bravo 2000) is a common ectoparasite of farmed salmonids in Chile. Sea lice can negatively impact the growth of hosts, adversely affecting aquaculture productivity. Unlike Lepeophtheirus salmonis (Krøyer, 1838), whose life cycle parameters have been well studied due to its importance in the Northern Hemisphere, for C. rogercresseyi no single source exists that quantifies the parameters required to model this ectoparasite's life cycle. Given that different species of sea lice have substantially different biological characteristics, it is important to parameterize the life cycle of C. rogercresseyi using appropriate observational data, rather than simply trying to adapt parameters developed for L. salmonis. Using data from existing literature, we quantified the development and survival rates for each stage in the C. rogercresseyi life cycle. We illustrate how development rates are affected by water temperature and explore the important impacts of salinity on rates of survival. We present equations that can be used to model development periods and survival proportions given certain water temperature and salinity profiles. While key parameters to quantitatively model the life cycle of C. rogercresseyi are presented, further research is required to adequately model the complete population dynamics of this ectoparasite on Chilean salmon farms and consequently to support decision-making to achieve effective control and mitigation.  相似文献   

Prospective Clinical Trial to Compare Vincristine and Vinblastine in a COP‐Based Protocol for Lymphoma in Cats     

E.L. Krick  R.B. Cohen  T.P. Gregor  P.C. Salah  K.U. Sorenmo 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2013,27(1):134-140

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Environmental Impact on Soil Nematodes Following the Use of the Ivermectin Sustained-release Bolus or the Nematophagous Fungus Duddingtonia flagrans to Control Nematode Parasites of Cattle in Sweden     

Gregor W. Yeates  Sten-Olof Dimander  Peter J. Waller  Johan Höglund 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(4):233-242

Management of nematode parasites of grazing livestock is essential, but there is concern about the potential environmental risk from agents used in their control. In this experiment, parasites in young cattle were controlled, using ivermectin boluses or the predacious fungus Duddingtonia flagrans , over 3 years. Treatment differences were sought among the soil nematodes recovered from soil samples collected from the paddocks on which treated animals grazed, and compared with similar samples taken from an untreated control paddock. Analysis of the soil nematode fauna on 21 occasions failed to demonstrate any impact of parasite management on soil nematodes. In 0-22 mm soil total nematode abundance averaged 524 000 m -2 , with 18 nominal taxa and H' diversity 2.41. There were both underlying paddock and year-to-year, climate-related, differences. The results of this trial not only confirm the lack of any adverse environmental impact of D. flagrans , a promising biological control agent, on soil nematodes, but also fail to show any impact arising from the use of ivermectin boluses.  相似文献   

A dynamic flow‐chamber‐based adhesion assay to assess canine platelet–matrix interactions in vitro     

Annika Ferkau  Silke Ecklebe  Kira Jahn  Simone Calmer  Gregor Theilmeier  Reinhard Mischke 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2013,42(2):150-156

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Efficient discrimination of oat and pea roots by cluster analysis of Fourier transform infrared (FTIR) spectra     

Annette Naumann  Gregor Heine  Rolf Rauber 《Field Crops Research》2010

Understanding belowground competition of plants requires a simple method for species identification of plant roots. This study investigates Fourier transform infrared (FTIR)-attenuated total reflexion (ATR) spectroscopy followed by cluster analysis for the discrimination of pea and oat roots. Pea and oat plants were grown under various conditions – in moist paper, soil-compost mixture, soil, in the greenhouse and field – to enhance the intra-species variability of their chemical composition. FTIR-ATR spectra of young-to-old roots from four independent experiments were recorded and represent, like a fingerprint, the chemical sample composition such as lipids, proteins, carbohydrates, etc. To group the spectra according to their spectral similarity in a dendrogram, cluster analysis was performed. The experimental approach discriminated pea and oat roots 100% successfully. The perfect discrimination of pea and oat roots, even from intercropped plants, strikingly demonstrates the potential of the method.  相似文献   

High organic carbon stock in a karstic soil of the Middle-European Forest Province persists after centuries-long agroforestry management   总被引：2，自引：0，他引：2  

Yousif Abdel-Rahman Ahmed  Viliam Pichler  Marián Homolák  Erika G?m?ryová  Dezs? Nagy  Magdaléna Pichlerová  Juraj Gregor 《European Journal of Forest Research》2012,131(6):1669-1680

Little is known on soil organic carbon (SOC) stocks in karst areas worldwide, although many of them have seen long-term application of agroforestry systems with a potential for carbon sequestration. Therefore, our study aimed to assess landscape-level SOC concentration and stock in the Silica Plateau, a part of the Slovak Karst Biosphere Reserve located in the Western Carpathians (Slovakia) with a centuries-long agroforestry record. The most represented local soil units are Chromi-Rendzic Leptosols and Chromic Cambisols with clayey loam texture, C/N ratio 9–12, and $ {\text{pH}}_{{{\text{H}}_{2} {\text{O}}}} $ 6.6–6.2 in their organo-mineral surface horizons. Mull surface humus form prevails under mixed forest stands dominated by hornbeam (Carpinus betulus L.), oak (Quercus petraea L.), and beech (Fagus sylvatica L.). A total of 2,700 soil samples were collected from 150 soil pits. Both SOC concentrations and stocks were determined for the 0–60?cm mineral soil layer. Soil stoniness was accounted for by means of electrical resistivity tomography. According to the analysis of covariance, cropland SOC concentration (0.026?g?g^?1) is significantly lower compared to forestland (0.040?g?g^?1) and pastureland (0.041?g?g^?1) (P?<?0.01). During the period of 130?years after forest clearing, cropland SOC stock has been reduced at an exponential decay rate of ca 0.002?year^?1, while the SOC stock in pastureland has increased following land use change from cropland by approximately 30% during the same period of time. Irrespective of land use history, overall SOC stock is high reaching on average 207.4?Mg?ha^?1, out of which 66% are stored within 0–30?cm and 34% within 30–60?cm soil layers.  相似文献   

Changes in soil nematode populations indicate an annual life cycle at Cape Hallett, Antarctica   总被引：1，自引：0，他引：1  

Gregor W. Yeates  Matthew B. Scott  Steven L. Chown  Brent J. Sinclair 《Pedobiologia》2009,52(6):375-386

Soil biological studies have suggested that generations of terrestrial nematodes in continental Antarctica may take many years. We sampled soil nematodes at three sites in the Adélie penguin colony at Cape Hallett on four dates in a two month sampling period (16 November 2002–18 January 2003). The size class distribution of over 3500 nematodes, and the occurrence of adults, indicate an annual life cycle of the bacterial-feeding Panagrolaimus davidi and Plectus murrayi, at each site. Nematode abundance ranged from 2 to 1375/g dry soil. Moderate temperatures and the regular presence of free water underlie this biological activity and related contribution to soil processes.  相似文献   

Long-term changes in topsoil nematode populations in grazed pasture under elevated atmospheric carbon dioxide     

Gregor W. Yeates  Paul C. D. Newton 《Biology and Fertility of Soils》2009,45(8):799-808

Increasing atmospheric CO₂ concentrations are expected to affect ecosystems processes, and while a New Zealand study reported a response in soil biological activity after 4 years of CO₂ enrichment, apparently reflecting increased populations of Longidorus elongatus, similar findings have not been reported from other sites. Soil microfauna in 0–10 cm soil under a sheep-grazed pasture on a sand was assessed quarterly in FACE rings that were either at ambient CO₂ or had been exposed to 475 μl l⁻¹ CO₂ for some 9 years. Although the area had been subject to a severe drought and microfaunal populations were lower than previously found, the effects of elevated CO₂ on microfaunal populations were broadly similar to those at 4 years. Average populations of the root-feeding L. elongatus increased from 67,000 to 233,000 m⁻² (3.48×) compared with a 4.26× increase after 4 years; microbial-feeding nematodes increased slightly, while predacious nematodes showed a 2.0× increase. A pot experiment showed an additive effect of elevated CO₂ and L. elongatus abundance in reducing specific root length. That similar effects have been found 4 and 9 years after CO₂ enrichment commenced suggests they are real, and emphasises the difference to other sites around the world where much lower responses to elevated CO₂ have been found. This, in part, reflects the unique combination of soil, plant and soil biological conditions at each site and confirms the strong effect of soil type and vegetation on soil biological processes. Just as the effects of global climate change on a given region are idiosyncratic, so it seems are the effects of elevated CO₂ on soil and ecosystem processes. In part, this reflects our limited understanding of below-ground processes.  相似文献