Volume and financial value of species traded in the medicinal plant markets of Gauteng,South Africa

The demand for traditional medicinal plants and products in South Africa has created an extensive cross-border industry involving thousands of harvesters and traders. The market values of individual taxa vary considerably. Pricing structures fluctuate between markets and over time as the cost of harvesting species varies depending on a gatherer's access to the resources and the proximity of markets to the harvesting sites. This paper estimates trade values, describes the prices paid for 22 plant resources, investigates pricing structures relative to the mass/volume sold and the factors that influence the market price for plants. There is an inverse and disproportionate relationship between the price per kilogram (R/kg) and mass of the product sold. The smaller the quantity sold, the higher the R/kg sale values are relative to sales of larger quantities. This relationship is evident in different plant part types (e.g. bark and bulbs), species and markets (shops and street markets). Given the high mass sold relative to the price, bulbs, like bark, have the lowest R/kg values compared to other products like roots, fruits and leaves. The prices paid for heavier/denser species is thus disproportionate to the mass sold. If the relative values are used as an indicator of plant vulnerability (assuming high values indicate greater vulnerability), then bias is created in favour of 'lighter' and less dense plant parts typically sold in small quantities because of the nature of the plant part and the manner in which it is marketed and required by customers.     

Utilization of partially predated snail shells by the hermit crab Pagurus longicarpus Say, 1817

The hermit crab Pagurus longicarpus was shown to inhabit shells that were partially predated from intertidal areas of Long Island, New York. Among field collections of P. longicarpus, 2.13% of the hermit crabs (46 of 2155) were found with shells with snail tissue present. Over 90% of these partially predated snail shells were occupied by male hermit crabs. Although hermit crabs were in 8 species of snail shells, only Littorina littorea and Nassarius obsoletus were found occupied by hermit crabs and containing snail tissue. In the laboratory, we found that specimens of the spider crab Libinia emarginata were able to pull off the operculum of snails, leaving damage as found in field collections. In contrast, specimens of P. longicarpus were not able to prey on live, healthy snails. When specimens of P. longicarpus were placed in communal tanks, hermit crabs preferred partially predated snail shells to empty and original shells. However, original shells and empty shells were occupied with more frequency than partially predated shells when crabs were isolated. These findings indicate P. longicarpus actively seeks shells soon after attack and abandonment by snail predators, especially in the presence of competitors.     

Host selection by a kleptobiotic spider

Why do kleptobiotic spiders of the genus Argyrodes seem to be associated with spiders of the genus Nephila worldwide? Observations following introduction of experimental insect prey of different sizes and weights on to host webs revealed that: (1) small prey are more effectively retained on the web of Nephila clavipes than on the web of another common host, Leucauge venusta. (2) N. clavipes did not consume small prey that accumulated on the web whereas larger, heavier prey were enveloped and stored. (3) We observed clear partitioning of prey items between N. clavipes and Argyrodes spp.; diet selection by Argyrodes did not overlap with that of N. clavipes but closely overlapped with that of L. venusta. (4) L. venusta responds very quickly to prey impact whereas N. clavipes is slower, offering a temporal window of opportunity for Argyrodes foraging. (5) The ability of L. venusta to detect and respond to small items also means that it acts aggressively to Argyrodes spp., whereas N. clavipes does not. Consequently, food-acquisition behaviours of Argyrodes were clearly less risky with N. clavipes compared with L. venusta. We conclude that when a kleptobiotic organism has a choice of various host species, it will opt for the least risky host that presents the highest rate of availability of food items. The fact that Nephila species present such characteristics explains the worldwide association with Argyrodes kleptobiotic spiders.     

The role of Raman spectroscopy in the analytical chemistry of potable water

Advances in instrumentation are making Raman spectroscopy the tool of choice for an increasing number of chemical applications. For example, many recalcitrant industrial process monitoring problems have been solved in recent years with in-line Raman spectrometers. Raman is attractive for these applications for many reasons, including remote non-invasive sampling, minimal sample preparation and tolerance of water. To a lesser extent, Raman spectroscopy is beginning to play a significant role in environmental analysis for the same reasons. At present, the environmental applications typically apply only to the most contaminated situations due to the still relatively high limits of detection. However, some emerging sampling technologies hold out the promise that Raman may soon be more widely applicable to the analytical chemistry of potable water. Herein we discuss these recent advances, summarize some examples of environmental applications to aqueous systems and suggest avenues of future developments that we expect to be most useful for potable water analysis. Also, a simplified, but detailed, theory of normal Raman scattering is presented. While resonance-enhanced Raman spectroscopy, surface-enhanced Raman spectroscopy and non-linear Raman techniques are briefly discussed, their theories and instrumental configurations are not addressed. Also, this article deals primarily with the modern dispersive Raman experiment (as opposed to the Fourier transform Raman experiment), because it seems most suited for potable water analysis. The goal of this article is to give the environmental scientist with no specialized knowledge of the topic just enough theory and background to evaluate the utility of this rapidly developing analytical tool.     

Monitoring of cadmium in "on" and "off" date palms

The study demonstrated that the mature dates we investigated were considered safe for human consumption. However, our findings revealed that much of the early fruit and leaves, which appeared at the advent of the fruiting season, possessed elevated levels of cadmium (Cd) that could accumulate in the food chain and thus impact adversely on the environment. In addition, animal feed for livestock contains date leaves, which should be restricted to the mature ones. The monitoring of cadmium in date palms is of considerable interest to environmental science and the thrust of this work, therefore, involved measurement, by ICP, of Cd in dates and corresponding leaf specimens, and evaluation of its distribution during the developmental stages of the fruiting season. Thirty-six date samples and 36 leaf specimens of the Fard cultivar were collected from "on" and "off" date palms during the Kimri, Bisir and Rutab stages of the fruiting season and subjected to suitable digestion procedures. Sample masses of typically 1 g (dry weight) were prepared in 25 ml dilute acid solution and investigated for trace levels of Cd by ICP-AES. Special attention was paid to contamination and the validation of our methodology. The Cd "threshold" in our study was 50 ng/g, in keeping with the levels of tolerance appearing in the literature. For the dates we found elevated levels of Cd [> 50 ng/g] in most of the samples, for both categories of "on" and "off" trees, during the Kimri stage. In the case of the leaves, the "on" samples revealed significant values up to 125 ng/g in Bisir, in some cases, but the trend for the "off" trees remained the same with the highest levels [> 100 ng/g] recorded during Kimri. Safe levels were attained during Rutab for all specimens. The possibility of a connection between Cd toxicity and the alternate-bearing phenomenon is discussed and this could be the subject of future interest.     

Genetic diversity and genetic structure in the brown alga Halidrys dioica (Fucales: Cystoseiraceae) in Southern California

Genetic diversity and genetic structure in a population of the brown seaweed Halidrys dioica Gardner were evaluated in five sites in southern California, USA, in 1991, using isozyme electrophoresis. H. dioica is relatively long-lived and has an outcrossing mating system and floating reproductive fronds with the potential for longdistance gamete dispersal. Because these characteristics are hypothetically important in determining genetic diversity and structure, we predicted that genetic diversity would be high and genetic structure would be exhibited only at relatively large geographic scales in H. dioica populations. The data were consistent with the prediction: genetic diversity (% polymorphic loci, no. of alleles/locus, average expected heterozygosity) was high compared to that of other seaweed species. Genetic structure (Wright's F statistics, Nei's genetic distance, point-pattern analysis of alleles) was low within and among distinct rocky reefs over 4 km of coast but high in subpopulations separated by 90 km. Life-history characteristics may be useful predictors of genetic diversity and structure in seaweed populations, but information on selection regimes, long-distance dispersal, and the extent of clonal propagation, for example, are critically lacking.     

Prioritizing Pacific Salmon Stocks for Conservation

Over 300 native stocks of Pacific salmon, steelhead, and coastal cutthroat trout (Oncorhynchus spp.) are at risk of extinction in the Pacific Northwest. With only limited resources available for conservation and recovery, prioritization of these stocks may become necessary if meaningful measures are to be implemented. We propose criteria by which prioritization may be guided. First, we rank stocks for risk of extinction, either by population viability analysis or by a set of surrogate measures. Then we rank stocks for biological consequences of extinction, using sets of questions designed to establish the genetic and evolutionary consequences and the ecological consequences if a stock were to become extinct. Together, these rankings allow stocks to be prioritized for a range of possible actions, with those stocks at highest risk and bearing the greatest biological consequences of extinction receiving attention first. Application of the prioritization process to 20 Pacific anadromous salmonid stocks worked as intended, although data limitations are considerable. The process is most likely to work successfully when applied to many stocks on which data exist, when several experts carry out the prioritization, and when the results are peer reviewed.     

Characteristics of vehicle-animal crashes in which vehicle occupants are killed

During the past 10 years almost 1,500 people have been killed in motor vehicle collisions with animals. Police reports on 147 fatal vehicle-animal crashes during 2000-2002 were obtained from nine states. The goal was to determine common crash types, types of animals involved, and steps that could be taken to reduce the crashes and injuries. Seventy-seven percent of the struck animals were deer, but six other types of animals were involved including small ones such as dogs. Eighty percent of the crashes were single-vehicle events. In most of these cases a motorcycle struck an animal and the rider came off the vehicle, or a passenger vehicle struck an animal and then ran off the road; in a few cases the animal went through the windshield. Multiple-vehicle crashes included vehicles striking deer that went through the windshields of oncoming vehicles, vehicles striking animals and then colliding with other vehicles, and vehicles striking animals that subsequently were struck by other vehicles. Crashes occurred primarily in rural areas, on roads with 55 mph or higher speed limits, during evening or nighttime hours, and in darkness. Greater application of deer-vehicle collision countermeasures known to be effective is needed, but it is noteworthy that a majority of fatalities occurred from subsequent collisions with other vehicles or objects, not from animal contacts. Sixty-five percent of motorcyclists killed were not wearing helmets, and 60% of vehicle occupants killed were unbelted; many of these fatalities would not have occurred with proper protection.     

Fibromyalgia after motor vehicle collision: evidence and implications

OBJECTIVE: Assess currently available evidence regarding the ability of a motor vehicle collision (MVC) to trigger the development of fibromyalgia (FM). METHODS: Consensus standards developed by the American College of Rheumatology Environmental Disease Study Group were used to assess the ability of an MVC to trigger FM. RESULTS: Increasing evidence suggests that FM and related disorders are characterized by abnormalities in central nervous system function related to sensory processing, autonomic regulation, and neuroendocrine function. MVC trauma appears capable of triggering FM, but generally not through direct biomechanical injury. Instead, the evidence suggests that MVC trauma can act as a "stressor," which in concert with other factors, such as an individual's biologic vulnerability, psychosocial factors, cultural factors, and so on, may result in the development of chronic widespread pain and other somatic symptoms. MVC trauma is only one of many stressors which can trigger such disorders, and the environment within which the stressor is experienced (biological and psychosocial) may largely determine whether there is an adverse physiologic result or not. CONCLUSIONS: The evidence that MVC trauma may trigger FM meets established criteria for determining causality, and has a number of important implications, both for patient care, and for research into the pathophysiology and treatment of these disorders.