bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal variation in the abundance, biomass and biodiversity of earthworms in soils contaminated with metal emissions from a primary smelting works
Authors: Spurgeon D. J. , Hopkin S. P.
Published: March 2003

1.Earthworms (Annelida: Oligochaeta) were sampled on four occasions (spring, summer, autumn and winter) at 14 sites along two transects from a primary lead/ zinc/cadmium smelting works at Avonmouth, UK.

2.Total abundance and biomass of earthworms decreased with proximity to the smelter. No worms were collected from the two sites closest to the factory (<0·6 km) and catches were significantly lower than controls at a further five sites (<3 km).

3.Seasonal composition of sampled communities differed only for summer with lower numbers of individuals and species collected at all sites. Reduced catches in the summer sample is a response to drought.

4.Species richness was lowest at sites close to the factory. For example, worms such asAporrectodea caliginosa(Savigny) andAllolobophora chlorotica(Savigny) that were dominant at relatively clean sites further from the smelter are absent from the most contaminated soils.

5.Reduced species richness resulted in lower Shannon–Weiner diversity and higher Berger–Parker dominance. Multivariate cluster analysis for spring, summer and winter indicated that sites could be split into three groups based upon relative species composition. In autumn, two clusters were identified.

6.The absence of sensitive species from sites close to the smelting works supports the inclusion of earthworms as a key group in a terrestrial prediction and classification scheme for quantifying the effects of pollutants on soil biodiversity. However, sampling should be carried out in spring or autumn to obtain an accurate picture of community structure.
A GIS‐supported model for the simulation of the spatial structure of wildland fire, Cass Basin, New Zealand
Authors: Perry George L.W. , Sparrow Ashley D. , Owens Ian F.
Published: March 2003

1. The behaviour of wildland fire in spatially heterogeneous landscapes was simulated using a model (PYROCART) that integrates the Rothermel fire spread model and a geographic information system (GIS).

2. The principal aims of the research were to test the applicability of overseas fire behaviour models to New Zealand ecosystems, and to assess the applicability of GIS to fire spread prediction.

3. The model was validated using an uncontrolled fire that occurred in the Cass Basin, South Island, New Zealand in May 1995. This fire burnt 580 ha across a complex vegetation mosaic comprising shrubland, stands ofNothofagus solandrivar.cliffortioides, bog and tussockland.

4. The overall predictive accuracy of the model was estimated to be 80%. Prediction accuracies within different fuel types and slope angles are also presented. Fuel type and slope appeared to be the dominant influences on fire spread. No trends in prediction accuracy by wind speed or direction were apparent. The predicted burnt area and the real burnt area had a similar overall shape. It was found, however, that at high wind speeds the model tended to over‐predict rates of fire spread in some directions.

5. The PYROCART model shows potential as a land management tool, especially for the testing of hypotheses concerning land management strategies. However, due to the complex input data and parameterization techniques it requires, it is less suitable forin situfire management.
Age‐ and sex‐specific behaviour in harbour sealsPhoca vitulinaleads to biased estimates of vital population parameters
Authors: Härkönen Tero , Hårding Karin C. , Lunneryd Sven Gunnar
Published: March 2003

1. Modelling of the population dynamics of seals require data on an array of vital parameters (fecundity, mortality, age structure, migrations, population growth rate). The most common way to obtain these data is to estimate the parameters from samples taken from the population. However, the influence from skewed samples can be substantial in populations with age‐ and sex‐specific features. By quantifying the behavioural differences among age and sex classes, data from skewed samples can be compensated retrospectively. Awareness of the existence and the potential magnitude of such biases is highly relevant for the design of surveys, sampling programmes and the implementation of management plans of age structured populations.

2. The age‐ and sex‐specific behaviour of harbour sealsPhoca vitulinaand grey sealsHalichoerus grypuscan be studied by using freeze‐branded animals. Since the brand is permanent and visible up to a distance of 500 m, the harassment is limited to one occasion in the lifetime of the seal (the catching day).

3. A method is also given for analysing data arising from re‐sighted branded animals, where re‐sightings of individual seals were transformed to estimates of relative haul‐out frequencies of seals by age and sex.

4. The composition of harbour seal groups on land exhibit a conspicuous seasonal flux, and the fraction on land was not representative of the entire population at any time during the summer. The results have far‐reaching implications since most studies of seals are carried out at haul‐out sites, and differential behaviour between the sexes and among age classes is expected in all populations and species of seals. Skewed samples generate biases in estimates of population growth rate, age‐specific mortality and fecundity.

5. Age‐specific haul‐out patterns must be taken into account when analysing data from populations with non‐stable age structures. As a consequence of changes in age structure after the 1988 seal epizootic, surveys under‐estimated the size of the Swedish–Danish harbour seal population by 6% in 1988 and over‐estimated the same parameter by up to 16% during the following years.

6. The present paper establishes the complications of sampling natural populations that are structured by age and sex, and presents a method on how to quantify sampling errors.
Simulated effects of logging on carbon storage in dipterocarp forest
Authors: Pinard M.A. , Cropper W.P.
Published: March 2003

1. As the role of forestry‐based options for reducing or mitigating greenhouse gas emissions is debated by policymakers, there is a need to inform the debate by synthesizing existing information on carbon dynamics in tropical forest systems and by applying this information to a range of possible interventions in forestry.

2. To investigate the consequences of reductions in logging damage for ecosystem carbon storage, we constructed a model to simulate changes in biomass and carbon pools following logging of primary dipterocarp forests in south‐east Asia. We adapted a physiologically driven tree‐based model of natural forest gap dynamics (FORMIX) to simulate forest recovery following logging.

3. Following selective logging, simulated ecosystem carbon storage declined from prelogging levels (213 Mg C ha−1) to a low of 97 Mg C ha−1, 7 years after logging. Carbon storage in biomass approached prelogging levels about 120 years after logging.

4. The relationship between fatal stand damage and ecosystem carbon storage was not linear, with biomass recovery following logging severely limited by 50–60% stand damage.

5. Results from simulations suggest that when 20–50% of the stand is killed during logging, replacing persistent forest species with pioneer tree species can reduce the site's potential for carbon storage by 15–26% over 40–60 years.

6. Reducing fatal damage from 40% to 20% of the residual stand, as was the case with a pilot project in Malaysia, was associated with an increase of 36 Mg C ha−1in mean carbon storage over 60 years.

7. Efforts to monitor and verify the benefits, either through carbon sequestration in new growth or carbon retention in existing biomass, of offset projects involving tropical forests and natural forest management should focus on above‐ground biomass, particularly the large trees. Selection of the most appropriate allometric equations for a site and species is important because of their influence on biomass estimates.
Modelling water chemistry for a major Scottish river from catchment attributes
Authors: Cresser M.S. , Smart R. , Billett M.F. , Soulsby C. , Neal C. , Wade A. , Langan S. , Edwards A.C.
Published: March 2003

1. The prediction of water quality is increasingly required in river catchment management, but methods are still developmental. We therefore derived empirical models to predict the concentrations of base cations, H+ and alkalinity at any point in a complex Scottish river system, and under diverse discharge conditions. Input data were readily available from geological and topographic maps, whole rock composition data and catchment land use inventories in geographical information systems (GIS).

2. A key and novel feature of the model was prediction using geological data for the riparian zone within 50 m of the river. The discharge contributions that passed through soil derived from each parent rock were estimated and used as weightings in predicting final run‐off quality.

3. Typical equations for upland catchments for mean, maximum or minimum river water Ca concentration, [Ca], were of the form [Ca] = a + b √{Carz}, where {Carz} denotes flow routing‐weighted rock CaO concentration of the riparian zone rock types present. These equations were significant at P < 0·0001. Similar approaches were applicable to alkalinity and to other base cations.

4. Predictions of [Ca] in catchments with mixed land use were improved by including model terms for catchment riparian zone cover of agriculturally improved (intensified) grassland and arable land. These results indicated anthropogenic effects on base cation flux that would not be represented by geological data alone.

5. Similarly, concentrations of Na, Mg and K were correlated with Cl concentration in the river water, primarily as a consequence of marine‐derived Cl. Including distance from the east coast as a predictive variable in place of [Cl] obviated the need for direct [Cl] measurement in model operation.

6. We advocate further work to assess whether similar models can be developed and applied in other geographical locations, where features such as land use, geology and sea salt inputs will all vary.
Large‐scale spatial variation in the breeding performance of song thrushesTurdus philomelosand blackbirdsT. merulain Britain
Authors: Paradis Emmanuel , Baillie Stephen R. , Sutherland William J. , Dudley Caroline , Crick Humphrey Q.P. , Gregory Richard D.
Published: March 2003

1. Spatial variation in breeding performance is of critical importance in understanding the large‐scale distribution and abundance of living species, and in understanding species conservation. We studied the large‐scale spatial variation in reproductive output of two species of declining British bird, the song thrushTurdus philomelosand the blackbirdTurdus merula.

2. We developed a method to predict spatial variation in reproductive output. Brood size and nest failure rates during the incubation and nestling periods were related to environmental factors using generalized linear models. Predicted values obtained from these models were combined to give values of number of fledglings produced per nesting attempt for 10‐km squares throughout Britain.

3. We observed substantial spatial variation in reproductive output for both species; the component that varied most was nest failure rate during incubation. We were more successful in relating environmental factors to spatial variation in reproductive output for song thrush than for blackbird.

4. Reproductive output in both species was affected mainly by factors that vary on a small spatial scale. Nest failure rate during incubation increased significantly where corvids were more abundant, suggesting a role for avian nest predators in determining spatial variation in reproductive output.

5. Our approach can be extended readily to other species of birds, to other taxonomic groups and to finer spatial scales. Such models could be used to evaluate the implications of current and proposed wider countryside management for spatial variation in breeding performance. Evaluations based on breeding success as well as numbers are likely to be more robust than those based solely on abundance.
Aggregation and temporal stability of carabid beetle distributions in field and hedgerow habitats
Authors: C.F.G. Thomas , Parkinson L. , Griffiths G.J.K. , Garcia A. Fernandez , Marshall E.J.P.
Published: March 2003

Understanding the spatial dynamics of insect distributions in farmland can provide insights into their ecological requirements and potential for management. Identifying the scale, location and persistence of species’ aggregations is an important step towards understanding the factors driving population distributions. This study examined how different carabid species were distributed in field and field margin habitats, and analysed their spatiotemporal dynamics.

 We sampled 156 locations in a grid of pitfall traps over approximately 1 ha, comprising a hedgerow and adjacent parts of two arable fields. Traps were monitored between June and November 1994 to provide data with high spatial and temporal resolution of the two‐dimensional distributions of six carabid beetle taxa.

 The pattern of carabid activity‐density over the experimental site was displayed in a series of contour plots. Spatial analyses by distance indices (SADIE) were used to provide aggregation indices (Ia) for the distributions of carabid species at different times.

A second SADIE index (Im) of spatial association between two sets of counts was used to measure the spatial stability of species’ aggregation patterns through time.Imwas also used to measure association or dissociation between the distributions of different species, and the spatial association between a species’ distribution and an environmental variable.

 Each taxon was aggregated most of the time, but different taxa aggregated in patches within the field and/or hedgerow to different and varying extents. The field boundaries were important for some species, either as the only habitat in which they occurred (Amaraspp.), as the major focus of more widespread distribution (Harpalus rufipes), or as a seasonal refuge (Nebria brevicollis). Within the crop habitat, different species also occupied different areas, providing some evidence to suggest species packing in space.

 Spatial distributions between consecutive samples were strongly and positively associated, indicating stability of patch location over short time‐scales. The strength of the association in turn was correlated with activity‐density. When time lags were introduced between sample distributions, some negative association indices indicated displacement of patches. In most cases, however, positive association was maintained over long periods, demonstrating patch stability.

 The spatial stability of patches suggests that future studies should focus on the detailed measurement of biotic and abiotic factors associated with patch location. Identifying the underlying causes of population distributions in farmland has important implications for managing habitat to enhance populations of beneficial predators, and targeting insecticide applications in precision agriculture to minimize their adverse side‐effects.
The effects of management on soil and plant carbon sequestration in slash pine plantations
Authors: Shan Jianping , Morris Lawrence A. , Hendrick Ronald L.
Published: March 2003

Intensively managed pine plantations in the south‐eastern United States can play an important role in global carbon sequestration both through accumulation of carbon in wood used in long‐lasting products as well as through increased soil carbon storage. Fertilization and understorey‐elimination are two commonly used intensive management practices in the south‐eastern United States that have the potential to increase carbon storage in vegetation and affect soil carbon.

In this study, we assessed the effects of these practices on carbon accumulation in vegetation biomass and in the soil of 17‐year‐old slash pinePinus elliottiiplantations in the flatwoods of northern Florida, USA.

Three treatments, fertilization, understorey‐elimination, and fertilization plus understorey‐elimination, were evaluated and compared with an untreated control.

All three treatments increased above‐ground biomass accumulation compared with the untreated control; understorey‐elimination also increased biomass of the forest floor litter, with or without fertilization.

Although understorey‐elimination increased above‐ground production, as a result of reduced below‐ground production total net primary production was decreased in plots from which the understorey was eliminated.

Soil carbon storage was lower in plots where the understorey was eliminated, with or without fertilization. This appeared to be the result of reduced fine root growth and mortality but also may have reflected reduced litterfall inputs early in the rotation.

Our results indicate that intensive management of pine plantations on sandy flatwoods soils can increase carbon sequestration, but these increases will be the result of increased carbon accumulation in biomass and its long‐term uses rather than through increased soil carbon.
Estimating group size and population density of Eurasian badgers Meles meles by quantifying latrine use
Authors: Tuyttens F.A.M. , Long B. , Fawcett T. , Skinner A. , Brown J.A. , Cheeseman C.L. , Roddam A.W. , Macdonald D.W.
Published: March 2003

Conservation issues and a potential role in disease transmission generate the continued need to census Eurasian badgers Meles meles, but direct counts and sett counts present difficulties. The feasibility of estimating social group size and population density of badgers by quantifying their use of latrines was evaluated.

The number of latrines, or preferably the number of separate dung pits, which were known from bait‐marking to be used by members of a social group, was positively correlated with adult group size estimated from mark–recapture studies at Woodchester Park and North Nibley (south‐west England). In the latter study area both latrine‐use measures were also significantly associated with total group size (i.e. including cubs and adults).

In spring 1997 and 1998, we quantified latrine use along strip transects, following linear features across four and five areas, respectively, in England, where badger density in summer was known from mark–recapture/resight studies.

Seven latrine‐use measures were evaluated with regard to their potential to predict badger density. Each measure separately explained between 62% and 91% of the variation in population density in a given year. The simplest measures (latrines km−1 and pits km−1) were most stable between years.

For these two simple latrine‐use measures, a linear model without an intercept term explained the highest proportion of variation in population density. A stepwise procedure to produce the best model selected only one (latrines km−1) of the two measures as an explanatory variable, indicating that pits km−1 is colinear with the former variable.

A badger census technique based on simple measurements of latrine use has great promise but needs to be validated across a wider range of badger populations, habitats, years, seasons and weather conditions.
Ecosystem recovery in restored headwater streams: the role of enhanced leaf retention
Authors: Muotka Timo , Laasonen Pekka
Published: March 2003

There is controversy over how the success of ecological restoration should be measured. Traditionally, emphasis has been placed on species diversity and other community attributes, whereas the restoration of ecosystem processes has received less attention. Here, we combine replicated field experiments and a field survey to provide an ecosystem‐level measure of stream restoration success.

Numerous headwater streams in Finland, and in many other parts of the world, have been channelized for timber transport, resulting in channels with simplified structure and flow. Recently, programmes have been launched to restore these streams to their pre‐channelization condition. While the efficacy of restoration in improving fish habitat has been tested, little is known about effects on other stream biota or on the retention of leaf litter, despite its importance in trophic dynamics of forested headwater streams. Using a before‐after‐control‐intervention (BACI) designed experiment with multiple reference and experimental streams, we examined restoration‐induced changes in retention efficiency by conducting leaf‐release experiments before (1993) and after (1996) restoration.

Substrate heterogeneity increased, but moss cover decreased dramatically following restoration. Retention efficiency in restored streams was higher than in channelized, but lower than in natural, streams. Algae‐feeding scrapers were the only macroinvertebrate group whose density increased significantly after restoration.

Aquatic mosses were a key retentive feature in both channelized and natural streams, but their importance to retention was strikingly reduced by restoration. During restoration work, mosses are detached from large areas of the stream bed, exposing bare stone surfaces for colonization by periphytic algae.

A more effective restoration technique would involve the use of moss transplants, or the addition of large woody debris, to increase retentiveness and thus enhance the availability of organic material to benthic consumers. This case study on rivers illustrates how restoration projects benefit from an ecosystem perspective and from measures of ecosystem processes in assessing restoration success.
Peat bog restoration by floating raft formation: the effects of groundwater and peat quality
Authors: Smolders Alfons J. P. , Tomassen Hilde B. M. , Lamers Leon P. M. , Lomans Bart P. , Roelofs Jan G. M.
Published: March 2003

A prerequisite for the restoration of desiccated bog remnants is rewetting the peat surface. Frequently in Europe, extensive areas are flooded in order to maximize water retention, and growth of peat mosses is often observed in the shallow zones. In deeper waters, regeneration appears to depend on whether residual peat will become buoyant and form floating rafts.

 In order to study the initial stages of peat bog regeneration, conditions required for peat buoyancy were studied on peat monoliths collected from three cut‐over bog remnants in the Netherlands. The effects of different peat quality and water chemistry on buoyancy of the monoliths, as well as growth ofSphagnum cuspidatumand nutrient availability, were followed in a glasshouse experiment.

 Both groundwater and peat quality affected the buoyancy of the monoliths and the growth ofS. cuspidatum. When groundwater containing bicarbonate (1 mmol l−1HCO3−, pH 6·0) was applied, the pH of peat monoliths increased fromc. 3·5 toc. 4·5 due to acid buffering. As a result, two of the peat types became more buoyant and the concentration, production and emissions of methane (CH4) increased. It was concluded that the increase in CH4production, induced by the increased pH, was responsible for the buoyancy.

 When groundwater contained both HCO3−(1 mmol l−1) and sulphate (1 mmol l−1), pH was further increased to approximately pH 5·0 due to alkalinity generated by the SO42–reduction process. CH4production, however, decreased because of interference from the SO42–, as confirmed in additional incubation experiments. Phosphate concentrations, however, greatly increased in the HCO3−/SO42–addition treatment due to the interaction between sulphide and iron phosphate precipitates.

 In one of the peat types, treatments did not influence CH4production and buoyancy, most probably because of its low decomposability. The chemical characteristics of the peat, notably the concentrations of lignin and soluble phenolics as well as C:N, C:P and C:K ratios, were all higher than in the other two peat types.

 The increase ofS. cuspidatumbiomass during the experiment appeared to be strongly related to the N:P ratios of the capitula, which differed considerably among the three peat types.

 We conclude that when bog remnants are inundated the prospects for bog regeneration are largely determined by peat quality and water chemistry. Peat mats with low concentration of lignin and phenolics and low C:N ratios are most likely to become buoyant in water with a higher pH, so providing suitable environments forSphagnumspecies. When peat quality is inadequate, either shallow inundation or the addition of suitable peat from elsewhere is indicated.
Long‐term vegetation recovery on reclaimed coal surface mines in the eastern USA
Authors: Holl Karen D.
Published: March 2003

While reclamation of degraded landscapes is becoming increasingly common, few studies have investigated the long‐term effects of reclamation efforts on plant conservation. The goals of this study were to determine whether vegetation communities on reclaimed mines approximate those of the surrounding forest, and to evaluate how intensive reclamation practices used to address short‐term erosion and water quality concerns affect long‐term recovery.

In 1992–93 and 1999 the vegetation on 15 coal surface mines reclaimed between the years 1967–87, and five periodically logged hardwood forest reference sites in south‐western Virginia, were surveyed.

Herbaceous species richness was similar on all sites, whereas woody species richness was higher in reference sites than in reclaimed sites.

Vegetation community composition on reclaimed sites continued to progress towards reference forest sites between the two sampling periods, but vegetation community composition even on the oldest sites (reclaimed > 35 years prior) still differed substantially from reference sites.

Herbaceous cover was higher and tree basal area was lower in reclaimed sites compared with reference sites at the first sampling period, but these differences were much less pronounced by the second sampling period.

The overall composition of the older reclaimed sites was similar to the reference forest sites, suggesting a high level of resilience in the forests studied. But, as with a number of previous studies of long‐term recovery on highly disturbed sites, a number of less common forest species still had not colonized reclaimed sites, raising the question of their value for conservation.

These results concur with a common theme that goals for short‐term and long‐term recovery of highly disturbed sites may conflict. Planting with aggressive non‐native ground cover species to minimize short‐term erosion may have slowed long‐term recovery on the sites studied. Widespread planting of Pinus strobus has not reduced species richness thus far, but may as the canopy closes. More emphasis should be given to long‐term recovery potential in developing mine reclamation plans, and strategies to further this goal should be tested.
Comparative surface-to-hand and fingertip-to-mouth transfer efficiency of gram-positive bacteria, gram-negative bacteria, and phage
Authors: Rusin P. , Maxwell S. , Gerba C.
Published: March 2003

Aims: To determine the transfer efficiency of micro-organisms from fomites to hands and the subsequent transfer from the fingertip to the lip. Methods and Results: Volunteers hands were sampled after the normal usage of fomites seeded with a pooled culture of a Gram-positive bacterium (Micrococcus luteus), a Gram-negative bacterium (Serratia rubidea) and phage PRD-1 (Period A). Activities included wringing out a dishcloth/sponge, turning on/off a kitchen faucet, cutting up a carrot, making hamburger patties, holding a phone receiver, and removing laundry from the washing machine. Transfer efficiencies were 38·47% to 65·80% and 27·59% to 40·03% for the phone receiver and faucet, respectively. Transfer efficiencies from porous fomites were <0·01%. In most cases, M.luteus was transferred most efficiently, followed by phage PRD-1 and S. rubidea. When the volunteers' fingertips were inoculated with the pooled organisms and held to the lip area (Period B), transfer rates of 40·99%, 33·97%, and 33·90% occurred with M. luteus, S. rubidea, and PRD-1, respectively. Conclusions: The highest bacteral transfer rates from fomites to the hands were seen with the hard, non-porous surfaces. Even with low transfer rates, the numbers of bacteria transferred to the hands were still high (up to 106 cells). Transfer of bacteria from the fingertip to the lip is similar to that observed from hard surfaces to hands. Significance and Impact of the Study: Infectious doses of pathogens may be transferred to the mouth after handling an everyday contaminated household object.
Acute and persistant effects of smoking on the baroreceptor function
Authors: Gerhardt U. , Vorneweg P. , Riedasch M. , Hohage H.
Published: March 2003

1. Recent studies showed that to smoke four cigarettes within one hour impairs baroreflex sensitivity in humans. In the present study, these effects were qualified more precisely from blood pressure and heart rate records by a sequence analysis and by Fourier analysis of Finapres‐registrations.

2. The Mayer waves of the heart rate PDS (power density spectrum), partially representing sympathetic activity, increased during smoking (83.7 ± 1.0 AU to 89.5 ± 1.1 AU, P≤ 0.05) and decreased after smoking (86 ± 1.0 AU, P≤ 0.05). They did, however, not reach baseline levels again within 30 min. Probably due to this, mean arterial blood pressure (64.3 ± 1.3 mmHg vs. 76.9 ± 1.3 mmHg, P < 0.05) and heart rate (71.8 ± 1.4 min–1 vs. 82.9 ± 1.4 min–1, P < 0.05) increased unequivocally after smoking. On the other hand, baroreflex sensitivity decreased dramatically from 15.4 ± 1 to 11.2 ± 0.6 ms mmHg–l (P < 0.05). This finding was associated with an increased heart rate variability after smoking (6 ± 0.5 min–1 vs. 9.2 ± 1 min–1)

3. Thus, the present study provides evidence that chronic tobacco (nicotine)‐abuse causes pathologic alterations of the baroreflex control. In synergism with other processes like elevated catecholamine blood levels, these alterations may contribute to the higher risk of cardiovascular diseases.
Changes of cardiac calcium homeostasis in spontaneously hypertensive rats
Authors: Manso A. M. , Encabo A. , Ferrer M. , Balfagón G. , Salaices M. , Marín J.
Published: March 2003

1 The aim of the present study was to assess the alterations in cardiac Ca2+ homeostasis induced by hypertension using electrically paced right ventricular strips from Wistar‐Kyoto (WKY) and spontaneously hypertensive rats (SHR).

2 Basal contractile force was higher in SHR than in WKY. Similarly, the β‐adrenoceptor agonist isoprenaline (10 n
m–10 μm) induced a concentration‐dependent positive inotropic effect that was higher in SHR than in WKY, which was in turn inhibited by the β‐adrenoceptor antagonist propranolol (1 μm) in both strains.

3 Preincubation of strips with the L‐type Ca2+ channel blockers, nifedipine (1 μm) or verapamil (10 μm), markedly inhibited the isoprenaline response, the inhibition being higher in SHR than in WKY. However, this inhibition was minor by the T‐type Ca2+ channel blocker mibefradil (10 μm).

4 Bay K 8644 (10 n
m–10 μm), a L‐type Ca2+ channel activator induced a concentration‐dependent positive inotropic effect, that was greater in SHR than WKY.

5 Nifedipine and verapamil (both 0.1 n
m–10 μm) inhibited in a concentration‐dependent way the inotropic effect induced by 0.3 μm isoprenaline or 1 μm Bay K 8644. The inhibition was higher in SHR than in WKY. Mibefradil (0.1 n
m–10 μm) only clearly inhibited the isoprenaline and Bay K 8644 inotropic effects at 10 μm in both strains.

6 The inhibitor of the sarcoplasmic reticulum Ca2+ release, ryanodine (10 n
m–10 μm), was a more effective depressor of isoprenaline‐induced response in SHR than in WKY.

7 These results suggest that cardiac Ca2+ homeostasis in SHR ventricular strips is altered compared with those of WKY, showing an increased Ca2+ entry through L‐type Ca2+ channels and release from sarcoplasmic reticulum; the participation of T‐type Ca2+ channels are irrelevant in this tissue.
Effects of noradrenaline, the calcium ionophore A23187, forskolin, sodium nitroprusside and glibenclamide on the degradation of extracellular adenosine 5′‐triphosphate by the rat isolated vas deferens
Authors: Tennant J. P. , Pearson A. , Hourani S. M. O.
Published: March 2003

1 The effects of noradrenaline (NA), the calcium ionophore A23187, forskolin, sodium nitroprusside (SNP) and the K+‐channel blocker glibenclamide on the degradation by ectonucleotidases of extracellular adenosine 5′‐triphosphate (ATP) were studied in the rat vas deferens.

2 ATP (100 μm) was rapidly broken down by the rat vas deferens with a half‐life of 5.83 ± 0.40 min via adenosine 5′‐diphosphate (ADP) and adenosine 5′‐monophosphate (AMP), with the final degradation product being inosine and with little adenosine being detected in the samples.

3 Preincubation for 1 h with NA (10 μm), A23187 (10 μm), or glibenclamide (100 μm) had no significant effect on the breakdown of ATP or the production of metabolites. However, both forskolin (10 μm) and SNP (1 μm) significantly increased the concentrations of AMP detected with time. In the case of SNP (1 μm) there was also a significant reduction in the rate of production of inosine, while in the case of forskolin (10 μm) there was a significant increase in the rate of removal of ATP.

4 These results suggest that preincubation with SNP may inhibit 5′‐nucleotidase and so reduce the metabolism of AMP, while preincubation with forskolin may increase the activity of the ectonucleotidases responsible for production of AMP from ATP.
Effects of allopurinol, erythro‐9‐(2‐hydroxy‐3‐nonyl)adenine and S‐(4‐nitrobenzyl)‐6‐thioinosine on the degradation of adenosine 5′‐triphosphate in the rat colon muscularis mucosae
Authors: Tennant J. P. , Callaghan F. , Turner C. , Hourani S. M. O.
Published: March 2003

1 The effects on ATP breakdown of some modulators of adenosine transport or metabolism were studied in the rat colon muscularis mucosae, a tissue which contracts to ATP and is thought to contain P2Y1 receptors. The compounds tested were the xanthine oxidase inhibitor allopurinol, the adenosine deaminase inhibitor erythro‐9‐(2‐hydroxy‐3‐nonyl)adenine (EHNA) and the adenosine uptake blocker S‐(4‐nitrobenzyl)‐6‐thioinosine (NBTI).

2 The degradation of adenosine 5′‐triphosphate (ATP) (100 μm) and the appearance of metabolites was followed by high pressure liquid chromatography during incubation of isolated tissue preparations alone or in the presence of the drugs, following preincubation with the drugs for 1 h.

3 In the absence of drugs ATP was rapidly degraded by the rat colon muscularis mucosae with a half‐life of 6.1 ± 0.7 min, the major breakdown product being inosine rather than adenosine. Allopurinol (1 μm) and NBTI (10 μm) had no effect on the rate of breakdown of ATP or on the pattern of metabolites produced. EHNA (1 or 10 μm) also had no effect on the half‐life of ATP, but in the presence of EHNA (1 μm) the rate of production of inosine was significantly reduced and some adenosine was detected, while in the presence of 10 μm EHNA the production of inosine was abolished and adenosine became the final breakdown product.

4 These results indicate that allopurinol (1 μm) and NBTI (10 μm) have no detectable effect on extracellular purine metabolism in this tissue, and that the build‐up of adenosine produced by treatment with EHNA does not have a feedback effect on ATP breakdown.
The role of heart rate in the modulation of the decreased cardiac output induced by acute nitric oxide synthesis inhibition in anaesthetized dogs
Authors: Faro R. , Tanus‐Santos J. E. , Zappellini A. , Antunes E. , De Nucci G.
Published: March 2003

1 The role of the heart rate modulating the decrease in cardiac output induced by the nitric oxide synthesis inhibitor Nω‐nitro‐L‐arginine methyl ester (L‐NAME) was investigated in anaesthetized dogs. This was achieved in dogs in which a positive pacemaker (PM) cable was located at the right ventricle.

2 The haemodynamic events were evaluated: mean arterial blood pressure (MABP), systemic vascular resistance index (SVRI), stroke volume index (SVI), heart rate (HR) and cardiac index (CI).

3 The infusion of L‐NAME (0.01–10 mg kg−−1) in the animals with the PM off caused a dose‐dependent rise in MABP and SVRI, accompanied by significant decreases of HR and SVI. A resulting decrease in CI was observed at all doses of L‐NAME used.

4 In the animals with the PM on, HR was maintained stable. Under this condition, the increase in MABP and SVRI as well as the decrease in SVI induced by the L‐NAME infusion did not significantly differ from the PM‐off animals. However, the resulting decreased CI was markedly attenuated compared to PM‐off animals but significant decreases in CI were still observed at higher doses of L‐NAME.

5 The results suggest that HR plays an important role in the L‐NAME‐mediated decreased cardiac output but other factors might also be involved.
Prostanoid release and constrictor responses to noradrenaline in the rat mesenteric vascular bed in non‐insulin‐dependent diabetes mellitus
Authors: Peredo H. A.
Published: March 2003

1 The administration of streptozotocin (STZ) to 2‐day old rats induced a non‐insulin‐dependent diabetes mellitus (NIDDM)‐like state, with mild hyperglycaemia and no alterations in body weight at the adult age.

2 In the isolated and perfused mesenteric vascular bed of NIDDM animals, the constrictor responses to either noradrenaline (NA) or potassium chloride (KCl) were not modified as compared with age‐matched non‐diabetic controls.

3 The reduction in NA contractions induced by the cyclooxygenase inhibitor, 10 μM indomethacin in the control group was absent in the NIDDM rats.

4 The increase in the NA‐induced contractions caused by endothelium removal was suppressed by indomethacin in the controls but not in the NIDDM group.

5 The prostanoid release from the mesenteric vascular beds of NIDDM rats was markedly reduced as compared with non‐diabetic controls. Noradrenaline increased production of the constrictor prostaglandin (PG) F2α in control but not in NIDDM rats.

6 In summary, these results show that in STZ‐induced NIDDM rats, there is an impairment of the prostanoid production, as well as a suppression of the role of prostanoids in the contractile effects of NA in the mesenteric vascular bed. These alterations are more severe than those previously observed in a model of insulin‐dependent diabetes mellitus (IDDM), in which hyperglycaemia and reduction of body weight were more marked. The conclusion is that, in these models of diabetes and in the preparation studied, vascular alterations and modifications of glycaemia and body weight are not closely related.
Effect of in vivo and in vitro ethanol on adrenergic and purinergic responses of the bisected rat vas deferens to low and high frequency pulses
Authors: Boselli C. , Govoni S.
Published: March 2003

1 This study investigates the effect of acute in vivo and in vitro ethanol administration on the contractions evoked electrically and by exogenous noradrenaline and α,β‐methylene‐ATP in the rat bisected vas deferens.

2 In vivo ethanol treatment (3 g kg–1, i.p.) significantly potentiated the early purinergic (phase I) and the delayed adrenergic (phase II) phases evoked by single‐pulse stimulation of the epididymal portion of the rat vas deferens, leaving unaffected both phases in the prostatic portion. In vitro 50 mM ethanol significantly depressed phase I leaving unaffected phase II in both portions from untreated rats. In vitro ethanol significantly depressed phase I in the epididymal portion from in vivo ethanol treated animals and potentiated phase II in both portions.

3 In vivo ethanol treatment (3.0 g kg–1, i.p.) selectively impaired the response to noradrenaline only in the prostatic portion of rat vas deferens while it was devoid of any action on α,β‐methylene‐ATP contractions. Ethanol 50 mMin vitro was devoid of any action on the response to exogenous noradrenaline and α,β‐methylene‐ATP in both tissues.

4 In vivo ethanol treatment slightly but significantly increased the phasic response in the epididymal portion to trains of stimuli (2–30 Hz). In vitro 50 mM ethanol was ineffective against the phasic and tonic contractions elicited by the tetanus in both portions.

5 It is concluded that ethanol treatment affects purinergic and adrenergic pathways of transmission possibly leading to a disruption of physiological contractions necessary to seminal emission.
Predicting changes in Fennoscandian vascular‐plant species richness as a result of future climatic change
Authors: Sætersdal Magne , Birks H. J. B , Peglar Sylvia
Published: March 2003

It is anticipated that future climatic warming following the currently enhanced greenhouse effect will change the distribution limits of many vascular plant species. Using annual accumulated respiration equivalents, calculated from January and July mean temperatures and total annual precipitation, simple presence–absence response surface plots are constructed for 1521 native vascular‐plant species in 229 75×75‐km grid squares within Fennoscandia. The contemporary occurrences in relation to present‐day climate and to predicted changes in climate (and hence annual accumulated respiration equivalents) are used to predict possible future immigrations and extinctions within each grid square. The percentage of potential change in species richness for each grid square is estimated from these predictions. Results from this study suggest a mean increase in species richness per grid square of 26%. Increases in species richness are greatest in the southern parts of the alpine/boreal regions in Fennoscandia. There are ten species that potentially may become extinct in Fennoscandia as a result of predicted climatic warming. Possible conservation strategies to protect such endangered species are outlined.
Tonnacypris glacialis (Ostracoda, Cyprididae): taxonomic position, (palaeo‐) ecology, and zoogeography
Authors: Griffiths Huw I. , Pietrzeniuk Erika , Fuhrmann Roland , Lennon Jack J. , Martens Koen , Evans John G.
Published: March 2003

Abstract. The freshwater ostracod Tonnacypris glacialis (Sars, 1890) is reported from the European Pleistocene for the first time. The historical allocation of the species is discussed, and the species composition and characteristics of Tonnacypris Diebel & Pietrzeniuk (1975) and its phylozoogeography are considered. The significance of T. glacialis is reviewed, particularly from the viewpoint of the possible implications of parthenogenesis (and occasional‐male production) for the Quaternary history of the genus, and for the use of the species in palaeoenvironmental reconstruction. It is suggested that the Pleistocene fossil occurrence of T. glacialis in modern temperature latitudes is a robust indicator of mean summer temperatures of 6°C.
A review of Bahamian ant (Hymenoptera: Formicidae) biogeography
Authors: Morrison Lloyd W.
Published: March 2003

Abstract. The results of recent surveys for ants on Staniel Cay, Exumas (and surrounding small cays) and the northeastern region of Andros are presented. These records are compiled with all previously published collection records of ants from the Bahamas into a single database. A list of all known Bahamian species is presented, in accord with current taxonomy. Distributions within the Bahamas are given, along with the status of each species with reference to its origin (endemic, native, or exotic). At present seventy‐five named species of ants are known from the Bahamas, which shares 60% of its ant fauna with Florida and 71% with Cuba. More than one third of the species (37%) are exotics, which appear to exist primarily in areas characterized by human disturbance, and apparently have not invaded the native vegetation to a large degree.

Both historical and ecological factors are likely to have played important roles in shaping present‐day Bahamian ant species diversity and distribution. The number of species on all major Bahamian islands from which ants have been collected is presented as a function of island area. Most islands have not been very thoroughly surveyed. The species‐area relationship for the more thoroughly surveyed islands is relatively flat (z= 0.06). Further collecting in this archipelago will probably lead to the discovery of additional species.
The effects of the Taupo Tephra eruption of c. 1718 bp on the vegetation of Mt Hauhungatahi, central North Island, New Zealand
Authors: Horrocks M. , Ogden J.
Published: March 2003

Abstract. An altitudinal series of eleven fine resolution pollen diagrams were used to examine the role of volcanism in forest dynamics on Mt Hauhungatahi. Partial pollen diagrams from four of these sites, chosen to illustrate the major effects of the 1718 bp Taupo eruption, are presented. Following the eruption Libocedrus bidwillii expanded in all sites. Open sites created by the eruption may have facilitated an expansion already underway as a result of more variable climatic conditions since c. 3000 bp. Weinmannia racemosa invaded upper montane forest c. 650 bp. The current altitudinal sequence of forest types, with Libocedrus dominating the subalpine and Weinmannia the upper montane forests, has thus been synthesized only within the last 1800 years. This is interpreted as a consequence of individualistic species' responses to major disturbance by the eruption. The results support nonequilibrium theories of community composition.
History, island area and habitat availability determine land snail species richness of Aegean islands
Authors: Welter‐Schultes F. W. , Williams M. R.
Published: March 2003

Aim We examined the species‐area relation of Aegean land snails, comparing different models to describe the relation. By examining those factors other than area that may also affect species richness, we tested whether the Aegean land snail fauna was more influenced by equilibrial migration and colonization processes, or rather is conservative and relictual.

Location The Aegean archipelago (Greece).

Methods Sixty‐five islands were examined. Data were taken from own collections and from literature sources. Multiple regression analysis was used to test the null hypothesis of no relationship between species richness and island area, elevation, distance to the next larger island, and the presence and extent of calcareous substrate.

Results The single most important factor determining land snail species number was area. While colonization‐extinction dynamics have frequently been cited to explain this result, this conclusion was not tenable in this study as it was contradicted by species number not being related to the islands’ distances to neighbouring larger islands, after accounting for other factors affecting species number. We also found that habitat diversity affected species richness even after accounting for the effects of area: both increased elevation and greater extent of calcareous substrate on islands resulted in higher species number. This effect was most likely due to the fact that particular ecological conditions increased the probability that particular species could survive on an island.

We compared the utility of the power and extreme‐value function models of the species‐area relation and found that both gave substantially the same results. However, fitting the power function model using nonlinear regression was of questionable utility.

Main conclusions We conclude that the snail fauna of the Aegean is relictual, not equilibrial. The unusually high number of land snail species found on Crete is consistent with this conclusion. Crete is a currently united island which was separated into at least six smaller islands for 7–9 million years during the Neogene. Our results are consistent with the hypothesis that Crete still hosts a large number of endemic species of these paleoislands, resulting in a total number of species in excess of what would be expected based on area alone.