Insect sampling in forest ecosystems

Forests have long been recognized as excellent model systems for studying insect ecology. The fact that many forests＇ ecosystems still function in a semi-natural state, with little influence from human disturbance, provides unique opportunities for understanding co-evolved community and population processes. Unfortunately the structural complexity of forests and the sheer size of trees often pose formidable problems when attempting to sample insects in forests. As such, any scientist embarking on a study of forest insect ecology would be well-advised to carefullv plan their sampling efforts.     

Shock wave therapy for femoral head necrosis—Pressure measurements inside the femoral head

There is a persisting need for effective therapies of femoral head necrosis, a common bone disease. Promising clinical results have been stated for the treatment with extracorporeal shock waves (ESW). However, the effective remaining pressure in the target region inside the femoral head has never been determined. Aim of this study was to investigate whether ESW are able to propagate through bone without an excessive loss of pressure. The remaining ESW pressure generated by an electromagnetic device after passing a certain intraosseous distance within the femoral head was measured. Standardized holes were drilled in porcine femora and the absorption in relation to reference measurements in degassed water was determined. The results showed continuous attenuation of shock waves in bone. After a clinical relevant intraosseous distance of 10 mm an ESW pressure of ～50% remained.In conclusion, ESW have the potential to reach necrotic regions with therapeutic pressure levels and to effectively treat femoral head necrosis.     

Aging: all in the head?

Global reduction in insulin signaling has been linked to extended life span in a range of organisms. New work on mice with brain-specific or whole-body reductions in insulin receptor substrate 2 (IRS2) (Taguchi et al., 2007) points to a role for insulin/IGF-1 signaling in the central control of mammalian aging.     

Gaps in fossil teeth: Saltations or sampling errors?

All evolutionists accept that there are gaps in the fossil record. To some, gaps are data: they mark sudden transitions, unlikely to be preserved, between one species and its descendants that have arisen by a brief genetic revolution within an otherwise stable lineage. However, recent studies of sediment gain and loss show that few fossil beds can be complete enough to give details of the process of speciation, so that most gaps are gaps, and nothing more. Differences in the perception of time and sampling completeness mean that paleontologists and geneticists see the rate and pattern of evolution in different ways. Just how misleading each view may be is seen by analysing the laws of life governing change in living populations using the limitations intrinsic to studies of past times; and by a new insight into the details of species formation now emerging from some remarkably complete primate fossil sequences.     

Do slope orientation and sampling location determine soil biota composition?

"Evolution Canyon" is a typical Mediterra-nean-basin canyon with a summer dry stream at the bottom and large differences in vegetation cover and solar radiation between the north-facing slope (NFS) and the south-facing slope (SFS). It is known to act as an abiotic mediator influencing the community structure of soil fauna. The aim of this study was to determine the spatial dispersion of soil microbial and free-living nematode communities in the open sites (between shrubs) in the upper (0-10 cm) soil layer at four altitudes on both slopes. The combination of relative soil moisture availability and temperature, known to be one of the main triggers for soil biota activity, was explained by slope orientation. The above-mentioned differences were found to significantly affect microbial biomass and CO2 evolution resulting in temporary stress, corresponding to higher values in metabolic quotient (qCO2) values. These differences may represent microbial investment in energy in order to overcome stress resulting from the microclimatic differ-ences between the two slopes. Moreover, the degree of substrate limitation (primary production due to the differences in plant cover) of microbial activity was explained by the difference in microbial functional groups. The total abundance of soil free-living nematodes was found to be 2-fold higher on the SFS than on the NFS. Thirty-nine genera, including 12 bacteria-feeders, 5 fungi-feeders, 12 plant-parasites, and 10 omnivore-predators, were found at the study site, with 34 genera on the NFS and 29 on the SFS. The generic diversity of the bacteria-feeding nematodes was higher on the SFS than on the NFS. This study elucidates the importance of slope orientation and its effect on the structural levels of soil microbial and nematode communities.     

Is pitfall trapping a valuable sampling method for grassland Orthoptera?

Common methods to assess diversity and abundance of Orthoptera are sweep netting, transect counts and box-quadrat sampling. Pitfall trapping, by contrast, is rarely used, and the value of this method is still being questioned. In 2008, we studied Orthoptera species richness and abundance in five vegetation types along a gradient of dune succession on the Baltic Sea island of Hiddensee (NE Germany) by comparing transect-count and pitfall-trapping data. Using transect counts, 12 species were detected in the study area. With pitfall traps, three chorto- and thamnobiont Ensifera species (C. dorsalis, M. roeselii and T. viridissima) were not caught at all, and it was only in low-growing and sparsely-vegetated grey dunes that all present species were detected. With pitfall traps, the proportion of present species recorded strongly declined with increasing height and density of the vegetation type. Assuming that transect counts are a good proxy for relative Orthoptera densities, densities ascertained by pitfall traps are strongly biased by vegetation structure and locomotive behaviour of the species. More than 80% of all individuals were caught in sparsely-vegetated grey dunes. Frequency patterns of the species also differed. Using pitfall traps, especially chortobiont species were significantly underrepresented. Qualitative and quantitative sampling of Orthoptera using pitfall traps seems only reasonable in habitats with low and sparse vegetation and a high proportion of geobiont species.     

Do bonobos say NO by shaking their head?

Head-shaking gestures are commonly used by African great apes to solicit activities such as play. Here, we report observations of head shaking in four bonobos apparently aimed at preventing the recipient from doing something. This may reflect a primitive precursor of the negatively connoted head-shaking behavior in humans. Further investigations are needed to clarify the preventive function of head shakes and their evolutionary role in the evolution of negation in humans.     

Rotifer sampling — a complete species list from one visit?

This paper describes a possible method of compiling a rotifer species list for any site from a single visit. Sediment samples collected from Loch Leven on one occasion in winter were exposed to light and a range of temperature conditions in the laboratory. Resting eggs in the sediment were induced to hatch. The resultant species list was very similar to that obtained from regular plankton collections over the previous six year period.     

Kinesin's walk: Springy or gated head coordination?

Conventional kinesin (kinesin-1) is a motor protein that performs a vital function in the eukaryotic cell: it actively transports cargo to required destinations. Kinesin pulls cargo along microtubule tracks using twin linked motor domains (heads) that bind the microtubule, hydrolyse ATP, and alternately step forward. The detail of the kinesin walk has yet to be discovered but a prominent theory is that the mechanism is rectified Brownian motion (RBM) biased by linker zippering. There is evidence that an ATP binding gate coordinates the heads. The hypothesis proposed here is that the gate is unnecessary, that entropic linker strain is sufficient to enable procession. An agent-based computer simulation has been devised to explore head coordination in the RBM model. Walking was found to emerge in silico without a gate to synchronise the heads. Further investigation of the model by applying a range of hindering loads resulted in backstepping or detachment with similar characteristics to behaviour observed in vitro. It is unclear whether kinesin waits at an obstacle but adding an ATP hydrolysis gate to the model in order to force waiting resulted in the model behaving less realistically under load. It is argued here that an RBM model free of gating is a good candidate for explaining kinesin procession.     

Organic nitrogen in precipitation: real problem or sampling artefact?

Published observations of organic nitrogen (N) compounds in precipitation go back almost a century. Several different methods have been used to measure both the total and ionic concentrations of N. There is therefore some uncertainty as to whether reported "organic N" is real, or simply the result of uncertainties in chemical analyses or inadequate sampling methods. We found that the materials from which the collector was made (polypropylene, steel, or glass) had no significant effect on the composition of dissolved organic N (DON). The use of a biocide was found to be very important during sampling and storage of samples before analysis. We set up a network of seven collectors across the U.K., from the Cairngorms to Dorset, all operating to the same protocol, and including a biocide. Samples were analysed centrally, using proven methods. Over 6 months, organic N contributed about 20% to the total N in U.K. precipitation, but with a large variation across the country. This means that current estimates of wet deposited N to the U.K., which are based only on the ammonium and nitrate concentrations, are too small. Organic N is not an artefact, but a real problem that needs to be addressed.     

Point pattern analysis under conditions of replicated sampling北大核心CSCD

Aims: The analysis of point patterns, which deals with data sets consisting of mapped locations of organisms in a study region, is especially important to plant ecological studies because the locations of plants can often be approximated as points. However, few studies used point pattern analysis with data collected by replicated sampling. a principle procedure of acquiring data in ecological research. Therefore, we explore the applicability of point pattern analysis under conditions of replicated sampling in this study. Methods: Three replicated 5 m × 5 m plots of homogenous communities were established on a site with eight years of restoration in Nei Mongol steppe. In each plot, the locations of individuals in Leymus chinensis and Stipa grandis populations were mapped. O-Ring function was used to describe the population patterns and species association between L. chinensis and S. grandis for each plot as well as the integrative data of the three replicates. Important findings: Population patterns and species associations differed among the three replicated plots. This illustrates that if point pattern analysis was applied to describe the population patterns and species associations only by using data from a single plot sampling, the results could be misleading. Whereas it would be more reliable to integrate the data of replicated plots in the point pattern analysis because in this way the resulting O-Ring function is a weighted average, where the weight is the number of points in the replicate i divided by the total number of points in all replicated plots.     

Monitoring and assessing old‐growth forest stands by plot sampling

Abstract

Forest inventories are evolving towards multipurpose resource surveys, broadening their scope by including additional topics such as biodiversity issues. Surprisingly, few quantitative surveys have been devoted to old‐growth forests, even if they constitute the most acknowledged forest biodiversity icons. In this framework, the use of probabilistic sampling may provide an effective as well as rigorous support for monitoring and assessing old‐growth forests. To this purpose, the present paper proposes a two‐phase sampling scheme. In the first phase, a coarse survey of few floristic and stand structural attributes is carried out by means of small plots systematically placed on the study area. Subsequently, in the second phase, a fine assessment of a large number of ecological attributes is performed on a subset of enlarged plots selected among the first‐phase ones by means of simple random sampling without replacement. The proposed sampling scheme is implemented for monitoring and assessing the old forests of Cilento National Park (southern Italy). Results and comments are provided as an exemplicative case study.     

Do slope orientation and sampling location determine soil biota composition?

“Evolution Canyon” is a typical Mediterranean-basin canyon with a summer dry stream at the bottom and large differences in vegetation cover and solar radiation between the north-facing slope (NFS) and the south-facing slope (SFS). It is known to act as an abiotic mediator influencing the community structure of soil fauna. The aim of this study was to determine the spatial dispersion of soil microbial and free-living nematode communities in the open sites (between shrubs) in the upper (0–10 cm) soil layer at four altitudes on both slopes. The combination of relative soil moisture availability and temperature, known to be one of the main triggers for soil biota activity, was explained by slope orientation. The above-mentioned differences were found to significantly affect microbial biomass and CO₂ evolution resulting in temporary stress, corresponding to higher values in metabolic quotient (qCO₂) values. These differences may represent microbial investment in energy in order to overcome stress resulting from the microclimatic differences between the two slopes. Moreover, the degree of substrate limitation (primary production due to the differences in plant cover) of microbial activity was explained by the difference in microbial functional groups. The total abundance of soil free-living nematodes was found to be 2-fold higher on the SFS than on the NFS. Thirty-nine genera, including 12 bacteria-feeders, 5 fungi-feeders, 12 plant-parasites, and 10 omnivore-predators, were found at the study site, with 34 genera on the NFS and 29 on the SFS. The generic diversity of the bacteriafeeding nematodes was higher on the SFS than on the NFS. This study elucidates the importance of slope orientation and its effect on the structural levels of soil microbial and nematode communities.