Avian utilisation on six salt marshes in New Jersey

Bird use was measured on six salt marshes in New Jersey from 18 April to 18 July 1977 (2 impoundments, 2 ditched marshes and 2 natural salt marshes) in terms of species diversity, numbers of individuals and biomass. Seventy-eight species of birds were recorded in all six marshes although not all species occurred on each marsh. Species diversity was highest on the impoundments, intermediate on the ditched marshes, and lowest in the natural marshes. Species diversity and the number of individuals directly related to the amount of open surface area. The traditional species typical of salt marshes on the East Coast of North America (clapper rails Rallus longirostris, seaside and sharp-tailed sparrows Ammospiza spp.) occurred primarily in the natural salt marshes and were absent from the impoundments. Considerations of species diversity suggest that diversity in salt marsh types is essential to maintaining high species diversity in salt marsh ecosystems. Red-winged blackbirds Agelaius phoeniceus and swallows were the most numerous species, followed by gulls and terns. The impoundments had over five times as many individuals as the natural marshes. Waterfowl, gulls, terns and waders accounted for over 90% of the cumulative biomass in the six marshes, with waterfowl contributing over 50%. This study suggests that conservationists should encourage the maintenance of natural salt marshes because they are necessary habitats for some species even though the diversity and avian biomass is less on natural salt marsh areas than it is on managed areas.     

Some aspects of purinergic signaling in the ventricular system of porcine brain

Background

Numerous signaling pathways function in the brain ventricular system, including the most important - GABAergic, glutaminergic and dopaminergic signaling. Purinergic signalization system - comprising nucleotide receptors, nucleotidases, ATP and adenosine and their degradation products - are also present in the brain. However, the precise role of nucleotide signalling pathway in the ventricular system has been not elucidated so far. The aim of our research was the identification of all three elements of purinergic signaling pathway in the porcine brain ventricular system.

Results

Besides nucleotide receptors on the ependymocytes surface, we studied purines and pyrimidines in the CSF, including mechanisms of nucleotide signaling in the swine model (Sus scrofa domestica). The results indicate presence of G proteins coupled P2Y receptors on ependymocytes and also P2X receptors engaged in fast signal transmission. Additionally we found in CSF nucleotides and adenosine in the concentration sufficient to P receptors activation. These extracellular nucleotides are metabolised by adenylate kinase and nucleotidases from at least two families: NTPDases and NPPases. A low activity of these nucleotide metabolising enzymes maintains nucleotides concentration in ventricular system in micromolar range. ATP is degraded into adenosine and inosine.

Conclusions

Our results confirm the thesis about cross-talking between brain and ventricular system functioning in physiological as well as pathological conditions. The close interaction of brain and ventricular system may elicit changes in qualitative and quantitative composition of purines and pyrimidines in CSF. These changes can be dependent on the physiological state of brain, including pathological processes in CNS.     

The immediate effects of ditching a saltmarsh on nesting herring gulls Larus argentatus

We examined the effects of water management for mosquito control on the behaviour and breeding success of a resident colony of herring gulls. The colony resided on three close islands, one of which was ditched in March before the start of the second breeding season. The number of breeding pairs on the ditched island remained the same before and after ditching although the breeding number increased by 46% and 90% on the other two islands. Breeding chronology was similar on all three areas. However, birds nesting on spoil laid eggs a mean of 8 days later than non-spoil nesting birds. Behavioural observations on aggression and display rates indicated that birds on spoil behaved similarly to those in open grassy areas but differed from those nesting in the bushes. Nest site selection, breeding densities, and breeding success were similar on all three islands. Thus the differences noted were attributed to the appearance of the marsh. We postulated that pairs having nested on the experimental island in the previous year continued to do so after the island was ditched. However, pairs searching for new territory did not move onto the island that was ditched, but instead colonised the nearby islands. Similarly, those pairs breeding on spoil nested later because of the need to defend their nest sites which were situated in areas used for displaying by unmated birds.     

Determination of elements removal in different harvesting scenarios of Scots pine (Pinus sylvestris L.) stands

Increasing demand for renewable energy and limiting CO₂ emissions have stimulated much interest in wood-based biofuels. Unfortunately, expanding the utilization of forest biomass may cause nutrient depletion in forested environments. This study investigates the element content from various parts of the tree. Comparisons were made between different harvesting scenarios and their impact on the amount of nutrients removed from the forest environment. The harvesting scenarios were: stem-only harvesting (SOH), branch and stem harvesting (BSH), and two variants of whole-tree harvesting (WTH). The elements taken into account were: carbon (C), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), sulphur (S), copper (Cu), iron (Fe), nickel (Ni), manganese (Mn), zinc (Zn), cadmium (Cd), chromium (Cr) and lead (Pb). To make the results comparable, the same amount of removed biomass was taken into calculation. The differences between harvesting scenarios were significant. The amounts of removed elements formed similar pattern: the lowest level was found in SOH, average in BSH, and highest in both variants of WTH. This confirms that the application of WTH is connected with increased risk of nutrient depletion, even when the volume of harvest would be equal to other variants.     

Inhibitory effect of natural phenolic lipids upon NAD-dependent dehydrogenases and on triglyceride accumulation in 3T3-L1 cells in culture

Alkylresorcinols are phenolic lipids present at levels of 0.03-0.15% in wheat and rye grains and almost 10 times higher in respective bran products. Despite numerous studies on the influence of dietary fibers on the regulation of energy metabolism, this issue still remains controversial. The objective of our current studies was to investigate whether 5-n-alk(en)ylresorcinols, natural phenolic components of high fiber human diets, may be considered as natural regulators of excessive fat accumulation. Our studies revealed that 5-n-alk(en)ylresorcinols isolated from wheat and rye bran inhibit glycerol-3-phosphate dehydrogenase, the key enzyme in triglyceride synthesis in adipocytes, specifically and effectively. Further in vitro studies showed that these compounds also prevent triglyceride accumulation in 3T3-L1 cells. The most effective compound in both systems was 5-n-heneicosylresorcinol. The results indicate that the potential to prevent triglyceride accumulation increases with the hydrophobicity of the phenolic inhibitor.     

Do domestic cats impose an unsustainable harvest on urban bird populations?

We assessed the impact of domestic cats on population persistence of native and exotic urban bird populations using a model adjusted for habitat-specific catch rates, cat ownership and hunting activity data. GPS-derived home ranges of 32 cats and resource selection indices demonstrated the degree of penetration and preference for native vegetation fragments. Owners reported on prey brought back by 144 domestic cats in Dunedin, New Zealand, during 12 months. One third of cats never brought back prey, and 21% returned more than one item/month. Cats brought back a mean of 13.4 prey items/year (median = 4), with cats aged <1 year returning more prey than older cats. Birds were the most common prey, followed by rodents. Although cats penetrated adjacent vegetation fragments they did not catch more birds and preferred garden habitat, suggesting that predation pressure may be reduced in fragments. Cat home range size appears to be constrained by cat density while the number of birds caught depends on the density of available prey. Estimates of city-wide catch for six bird species were either more than total urban population size estimates or close to lower confidence intervals. Modelling of three species indicated low likelihood of population persistence with cat predation. The observed persistence of these prey species suggests a meta-population structure with urban populations acting as sinks with source populations located on the city fringe.     

Chemical pre-treatment of snapdragon spikes to increase cut-flower longevity

The longevity and quality of freshly cut snapdragon (Antirrhinum majus L.), as well as those kept under simulated transport, were enhanced by 20 h pre-treatment with a solution containing silver thiosulphate and sucrose, compared to those pre-treated with silver nitrate on sucrose alone. Solutions of silver nitrate, sucrose and EDTA or 8-HQC as a complexing agent were less effective in prolonging snapdragon vase-life. The results of experiments with radioactive silver showed that spikes treated with silver thiosulphate solution accumulated the greatest amount of silver, especially in the shoots.