The efficiency of a new lightweight suction sampler for sampling aphids and their predators in arable land

A petrol driven machine, normally used to collect leaf litter, was modified to be used as a suction sampler for polyphagous predators in cereals and grassy habitats and aphids in cereals. Recovery efficiency of Araneae, Carabidae and Staphylinidae did not differ significantly between winter sampling from Agrostis stolonifera, Dactylis glomerata, Festuca rubra, Holcus lanatus or Lolium perenne although the structure of these grasses was very different. Summer sampling of aphids and their predators in winter wheat showed that the new sampler captured significantly more target organisms per unit area than did a traditional suction sampler. The machine was also lighter, cheaper and much easier to use than a traditional machine.     

A simple and inexpensive apparatus for measuring fish metabolism

A simple, noninvasive, and economical home-made respirometer has been used to determine the standard metabolism of goldfish. The apparatus has been tested on several fishes and has proved its accuracy in determining a mass effect on standard metabolism. The apparatus can be made easily by middle school, high school, and undergraduate students and can be used to introduce them to basic concepts in animal physiology and in biological statistics.     

D-vac sampling for predatory arthropods in winter wheat

We evaluated the D-vac suction machine for sampling predatory arthropods in Oklahoma winter wheat fields. The efficiency of D-vac sampling was low for adult Coccinellidae and Carabidae. Sampling efficiency was greater for coccinellid larvae. Sampling efficiency was high for adult and immature Nabidae and Chrysopidae, for Araneae, and for adult Staphylinidae. For most predators, there were significant correlations between the number of individuals in D-vac samples and the number of individuals per m² in the field. The highest correlation was 0.82 for adult Staphylinidae. Correlations for most predators were <0.60. Significant partial correlations between D-vac sample estimates and ancillary abiotic and biotic variables occurred for most predators, indicating that D-vac sampling efficiency was affected environmental variables. Multiple regression models were constructed to relate population estimates from D-vac sampling to absolute density by adjusting estimates for influential abiotic and biotic environmental variables. Significant regression models were not achieved for adult Coccinellidae or adult Carabidae, and the coefficient of determination was low (0.18) for the model for adult Nabidae. Higher values of R² were achieved for larval Coccinellidae, Chrysopidae adults and larvae, Nabidae nymphs, Araneae, and adult Staphylinidae. Among abiotic variables, air temperature and wind velocity most frequently entered into step-wise regression models. Among biotic variables, wheat plant growth stage and wheat tiller density frequently entered into models.     

Description of a new submersible filter-pump apparatus for sampling plankton

A low-volume submersible filter-pump apparatus was designed for the collection of zooplankters and other aquatic organisms in all aquatic ecosystems, particularly rivers and power plant cooling lakes. The device combines the best features of pumps and tow net samplers by enclosing both pump and filter into a submersible unit that functions conveniently in a continuous and simultaneous operation. Compared to conventional tow net samplers, the Waite-O'Grady filter pump collected greater numbers of rotifers and immature copepods per unit volume and fewer numbers of mature copepods, while the capture rate of cladocerans was virtually the same. The filter-pump apparatus can be easily modified for the sampling of a variety of other aquatic organisms including macroinvertebrate drift, ichthyoplankton, and net phytoplankton.     

群落内物种多样性发生与维持的一个假说

本文根据作者对竞争排除法则的研究而提出了一个新的群落多样性假说。按照作者的观点,占用相同生态位的物种可以稳定共存;这样,群落内物种多样性将受到４个基本因子所控制。它们分别是：（Ⅰ）生态位的数量;（Ⅱ）区域物种库的大小;（Ⅲ）物种迁入速率,以及（Ⅳ）物种灭绝速率。该假说强调区域生物地理过程与局域生态过程共同决定了群落内种多样性的大小及分布模式。     

A model of nitrogen flows in grassland

Abstract. The model comprises three submodels, which together give an integrated picture of nitrogen pools and fluxes in grassland under grazing or cutting. The first submodel represents the interaction of the grazing animal with the sward through intake and the production of excreta: the second is concerned with the growth of the vegetative grass crop and its response to light, temperature and nitrogen; these two submodels are interfaced with a submodel of soil carbon and nitrogen pools and processes, including dead shoot and root material, dead and live soil organic matter, and three pools representing mineral nitrogen. No account is taken of water, which is assumed to be non-limiting, or the possible effects of soil pH and soil aeration. The model is used to simulate a range of management strategies as applied to stocking density and fertilizer application, examining both steady-state and non-steady-state conditions. The model highlights the long time scales associated with grassland systems, the role of the grazing animal in modifying carbon and nitrogen flows, and the importance of soil conditions to grassland productivity and fertilizer response. The productivity of grazed swards may be greater or less than that of cut swards depending on stocking density and fertilizer application, although nitrogen recovery (as calculated here) is always lower in grazed swards. The model is able to stimulate mineralization and immobilization, and place these in the context of plant processes and the grazing animal.     

A simple,inexpensive apparatus for rotating bottles during zooplankton feeding experiments

By using the bearings in the hub of bicycle wheels to support the weight of jars containing zooplankton and experimental food, a small laboratory stirring motor can be used to slowly rotate several kilograms of jars for zooplankton feeding experiments. This apparatus is quickly assembled from easily obtainable parts at almost no cost.     

Branchlet shaking: A method for sampling tree canopy arthropods under windy conditions

Abstract Chemical knockdown is a commonly used method for sampling canopy arthropods. The procedure is susceptible to high winds and in certain conditions may be virtually unusable. Here we introduce a new procedure, branchlet shaking, and compare it with chemical knockdown. Samples produced by branchlet shaking yield fewer arthropods per tree and tend to miss some larger (>1.0cm) and some smaller (<0.2cm) animals. However, the two procedures generally produce data which can portray similar information about the canopy fauna. It is concluded that although chemical knockdown is a superior sampling procedure, branchlet shaking is a possible alternative for situations where chemical knockdown is impractical. Interpretation of the data must, however, take into account the limitations of the branchlet shaking procedure.     

A proposed framework for determining the environmental impact of replacing agricultural grassland with Miscanthus in Ireland

Energy crops offer an opportunity to substantially increase bioenergy resources which can replace rapidly depleting fossil fuel reserves and mitigate the effect of climate change. Energy crops are typically established within traditional agricultural systems such as tillage land or grassland. Associated land use conversion has environmental implications. The aim of this paper is to propose a framework to examine how such environmental implications can be assessed, based on (a) a Strategic Environmental Assessment (SEA) approach which considers potential impacts at different stages of a plan across a wide range of environmental receptors and (b) a literature review. The example we used was that of Miscanthus replacing grassland farming. This scenario is particularly relevant to Ireland, where over 90% of the agricultural land is permanent pasture, but is also applicable to grassland conversion throughout Europe and the United States. Two consecutive phases of land‐use change were identified for assessment, each with a distinct set of environmental impacts. The first was a transition phase, lasting from initial livestock clearance and grassland ploughing until the Miscanthus crop became established (2–3 years). The second phase was the mature crop phase, lasting up to 25 years. Miscanthus cultivation was more likely to impact negatively on the environment during the transition phase than the mature phase, primarily due to abrupt disturbance and the time required for a new equilibrium to establish. However, a literature review of the impact on the environmental receptors revealed that replacing Irish agricultural grassland with Miscanthus had the potential to improve biodiversity, water, air and soil quality, and climatic factors once the crop became established and reached maturity. In order to confirm these findings an appropriate monitoring programme involving objectives and indicators associated with each environmental receptor would need to be developed.     

The efficiency of an insect suction sampler in grassland

Abstract. 1. Capture efficiency was determined chiefly by insect type: Diptera 79–98%, Hymenoptera 60–83%, Homoptera 32–76%, Thysanoptera 27–62%, Acarina 12–40%.
2. Grass length also affected efficiency, but to a lesser degree.
3. Prolongation of the sampling period increased the proportions of some groups more than others.
4. Capture efficiency for any group was not affected by the number of individuals present.
5. Catch size did not vary with time of day.
6. The method was unsatisfactory for wet grass.     

A simple apparatus for sampling epiphytic communities associated with emergent macrophytes

The apparatus allows the sampling of both algal and animal components of the epiphyton. It consists of a perspex tube, 100 cm long with an internal diameter of 4 cm, and of an epiphytic sieve. The latter is made of two 2.5 cm cross-sections of perspex tubing with a piece of circular mesh glued between them. While sampling, a randomly chosen shoot is isolated from the ambient water by means of the tube, cut at the bottom sediment and removed together with epiphyton. The water, taken together with the shoot is then removed using the epiphytic sieve, joined with the tube under the water surface. The detached organisms, associated with the stem and those scraped from the stem with a stiff brush afterwards, concentrate on the mesh.     

锡林郭勒草原自然保护区土壤动物初步调查

土壤动物的生存、活动与栖息地环境密切相关。一方面栖息地生态因子决定着土壤动物的生存与活动;另一方面,土壤动物对土壤有机质的改变、土壤微生物的生存、植物的生长等诸生态因子的变化起着一定的促进作用。因此随着草原生态系统研究的日趋深入,土壤动     

Comparison of pitfall traps and litter bags for sampling ground-dwelling arthropods

Abstract:  For their simplicity and effectiveness, pitfall traps have become a standard technique to measure the activity and relative abundance of ground-dwelling arthropods. Permeable screen or mesh bags filled with plant material, referred to as litter bags, have also recently been employed as a complementary sampling technique for epigeal taxa. The anticipated need for increased field research on arthropod populations, particularly in transgenic crops with insecticidal properties, suggests that a relative assessment of both sampling methods could contribute to the design of future studies. Comparisons among pitfall traps, and litter bags placed above- or below-ground indicated that above-ground litter bags most frequently succeeded in collecting certain groups of arthropods associated with moisture and sheltered areas, including centipedes (Chilopoda) and beetle larvae (Carabidae, Staphylinidae). Conversely, pitfall traps most often captured taxa considered active at ground level, such as adult carabids or harvestmen (Opiliones). For taxa collected in >40% of all three trap types, bootstrap confidence intervals for the coefficient of variation (CV; used to assess precision or sampling efficiency) showed that above-ground litter bags were significantly more precise than pitfall traps for sampling elongate springtails (Collembola) and adult rove beetles (Staphylinidae), but only during the first year of sampling. While below-ground litter bags often appeared similar to one or both of the other trap types, in no case were below-ground litter bags best based on frequency of collection or CV. Though differences were not always consistent between years, results suggest that the additional effort required to sample using litter bags may be justified for the collection of some ground-dwelling taxa.     

A new apparatus for CT-guided stereotactic surgery

Combining whole-body CT scan with a stereotactic system, the authors have developed and applied clinically an apparatus which readily provides intraoperative CT images, making it possible to confirm the location of the target point and ascertain the intraoperative environment. It takes about 9 s to obtain a CT image. Our purpose is to make stereotactic surgery, a kind of blind surgery, as safe and reliable as a visualized procedure by intraoperative CT scanning. By the method, in which there is very little invasion under local anesthesia, evacuation of deep-seated intracerebral hematomas as well as brain abscesses and also biopsy or brachytherapy of brain tumors in the brain can be done with safety and reliability.     

A new sampling formula for neutral biodiversity

The neutral model of biodiversity, proposed by Hubbell (The Unified Neutral Theory of Biodiversity and Biogeography, Princeton University Press, Princeton, NJ, 2001) to explain the diversity of functionally equivalent species, has been subject of hot debate in community ecology. Whereas Hubbell studied the model mostly by simulations, recently analytical treatments have yielded expressions of the expected number of species of a particular abundance in a local community with dispersal limitation. Moreover, a formula has been offered for the joint likelihood of observing a given species‐abundance dataset in a local community with dispersal limitation, but this formula is too complicated to allow practical applications. Here, I present a much simplified expression that can be regarded as an enhanced version of the famous Ewens sampling formula. It can be used in maximum likelihood methods for quick estimation of the model parameters, using all information in the data, and for model comparison. I also show how to rapidly generate examples of species‐abundance distributions for a given set of model parameters and how to calculate Simpson's diversity index.