bluuebunny/crossref_metadata_2025 huggingface dataset:
Arrhythmogenesis in isolated rat hearts with enhanced α‐adrenoceptor‐mediated responsiveness
Authors: Chess‐Williams R. , Milton H. L.
Published: March 2003

1 It has been postulated that stimulation of myocardial α‐adrenoceptors is one of the primary mediators of the dysrhythmias which occur during periods of myocardial ischaemia and reperfusion. This study examines arrhythmogenesis during coronary artery occlusion and reperfusion in isolated perfused rat hearts from control animals and from rats with enhanced myocardial α‐adrenoceptor responsiveness.

2 Rats were administered propylthiouracil (PTU) in their drinking water for 8 weeks. This treatment resulted in an enhanced responsiveness of isolated left atria to the α‐adrenoceptor agonist phenylephrine compared with atria from control animals.

3 In Langendorff‐perfused isolated hearts, the spontaneous rate of contraction was significantly lower in the PTU‐pretreated group than in either age‐matched or weight‐matched controls. Occlusion of the left anterior descending artery (LAD) for 25 min resulted in ventricular tachycardia (VT) of similar incidence and duration in all groups and ventricular fibrillation (VF) in both control groups but not the PTU‐pretreated group.

4 Following the 25‐min ischaemic period the myocardium was reperfused for 10 min. The incidence and duration of VT and VF during this period was similar in all groups except that the duration of VF in the PTU‐pretreated group was significantly lower than in controls.

5 In perfused hearts paced at 4 Hz, the incidence and duration of dysrhythmias during ischaemia and reperfusion was again similar in all groups, only the duration of VF being affected (reduced) by PTU‐pretreatment.

6 In conclusion, this study does not lend support to the hypothesis that myocardial α‐adrenoceptors have a primary role in arrhythmogenesis, but the data would support a role for these receptors in myocardial protection.
Modulation of M‐channel conductance by adenosine 5′ triphosphate in bullfrog sympathetic B‐neurones
Authors: Chen H. , Kurennyi D. E. , Smith P. A.
Published: March 2003

1 Adenosine 5′ triphosphate (ATP) (0.5–500 μM) or muscarine (0.1–1.0 μM) suppressed M‐current/conductance (IM/gM) in B‐cells of bullfrog sympathetic ganglion. Both agonists suppressed steady‐state M‐conductance (gM) at –30 mV and there was either no change or a slight increase in the time constants for gM activation (τa at –30 mV) and deactivation (τd at –50 mV).

2 It has previously been shown that experimental elevation of intracellular Ca2+ concentration ([Ca2+]i) suppresses gM and this is associated with decreases in both τa and τd. As these changes in kinetics differ from those we observe with agonist application, our results cast doubt on the hypothesis that elevation of [Ca2+]i is involved in the transduction mechanism for ATP‐ or muscarine‐induced gM suppression.
Effects of natural tachykinins on ovine lower urinary tract smooth muscle
Authors: Tucci P. , Bolle P. , Severini C.
Published: March 2003

1 Numerous studies have demonstrated that the urinary bladder is particularly sensitive to tachykinins; rat, rabbit and guinea pig bladders, besides human detrusor, have been the most extensively studied, whereas very little is known about most large animal detrusors. The aim of this work was to study natural tachykinin activity on the lower urinary tract of ovine to make a comparison with data obtained in laboratory animals.

2 As in other animal species, tachykinins are also able to contract ovine bladder smooth muscle.

3 The results reported in this study indicate that in ovine bladder, neurokinin 2 (NK2) receptors are expressed most. In fact, on lamb and sheep bladder neurokinin A (NKA), a NK2‐ almost selective peptide, was shown to be > 100% more active than the natural tachykinins kassinin (KASS) and eledoisin (ELED). Eledoisin was shown to be 50% less active than KASS, which is typical behaviour for an almost exclusively NK2 receptor population. Moreover, NK1‐ preferential peptides, namely substance P (SP) and physalaemin (PHYS), showed a lack of activity even when applied at high concentrations.

4 The results reported in this study show that lamb and sheep detrusor represent a good alternative model for the characterization of NK2‐selective tachykinins.
Functional effects of dextran sulphate sodium (DSS) treatment on the longitudinal muscle of rat distal colon
Authors: Börjesson L. , Aldenborg F. , Delbro D. S.
Published: March 2003

1 The current study addressed how acute colitis, induced in male Sprague–Dawley rats by the administration of dextran sulphate sodium (DSS) in their drinking water, may affect some functional properties of the longitudinal muscle layer of the distal colon.

2 Dextran sulphate sodium was provided at a concentration of 3% for 3 or 7 days, or 5% for 7 days, and the rats were thereafter killed. Specimens of the distal colon were taken for histology or for organ bath experiments.

3 The colitis score increased significantly with increasing dose of DSS administered. At 5% concentration, there was sometimes even transmural inflammation. Functionally, there was a progressive increase in optimal preload (Po) for the contractile response to carbachol (1 μM), in relation to the severity of the colitis. At 5% DSS, the magnitude of the response to carbachol at Po was significantly increased compared with control rats. Such an effect could not be verified when, instead, K+ (60 mM) was used as a spasmogen.

4 It is concluded, that the colitis score increased in severity progressively with increasing amounts of DSS administered. The longitudinal muscle layer was functionally affected by the inflammation. Thus, there was a progressive increase in optimal preload for muscle contraction. Moreover, severe colitis resulted in an increase of the contractile response to carbachol, while a significant increase in the response to depolarization with K+ could not be found.
A morpholinocatechol compound (UK42620) with clonidine‐ and tyramine‐like actions
Authors: Thaina P. , Nott M. W. , Rand M. J.
Published: March 2003

1 The actions of a morpholinocatechol (UK42620) were studied in rat isolated atria preparations consisting of spontaneously beating left and right atrial pairs.

2 UK42620 produced positive inotropic and chronotropic responses and, in atria that were incubated with [3H]‐noradrenaline, it also produced a massive increase in the release of radioactivity.

3 These actions of UK42620 were similar to those of tyramine and were blocked by the β‐adrenoceptor antagonist propranolol (0.3 μM) and by the neuronal uptake blocker desipramine (1 μM).

4 In the presence of desipramine, UK42620 but not tyramine produced a decrease in the stimulation‐induced efflux of radioactivity that was antagonized by idazoxan.

5 Thus, UK42620 had prejunctional α2‐adrenoceptor activity like that of clonidine‐ and tyramine‐like activity releasing large amounts of noradrenaline.
Modification of cardiovascular responses to adenosine A1 receptor stimulation in the posterior hypothalamus of anaesthetized rats by cAMP and by GABAB receptor blockade
Authors: Lee H. H. , Koh H. C. , Chae S. L. , Kang J. S. , Lee C. H. , Paik D. J. , Shin I. C.
Published: March 2003

1 Injection of N6‐cyclohexyladenosine (CHA; 1, 5 and 10 nmol), an adenosine A1 receptor agonist, into the posterior hypothalamus of rats produced a dose‐dependent decrease in blood pressure (BP) and heart rate (HR).

2 Pretreatment with 8‐cyclopentyl‐1,3‐dimethylxanthine (CPDX; 50 nmol), an adenosine A1 receptor antagonist, blocked the depressor and bradycardic effects of CHA (10 nmol).

3 Pretreatment with 8‐bromo‐cyclic adenosine monophosphate (AMP) (10 nmol), a cAMP analogue, attenuated the depressor and bradycardic effect of CHA (10 nmol); 8‐bromo‐cyclic guanosine monophosphate (GMP) (10 nmol), a cGMP analogue, did not modify those effects of CHA.

4 In addition, pretreatment with 5‐aminovaleric acid (25 nmol), a γ‐aminobutyric acid (GABA)B receptor antagonist, attenuated the depressor and bradycardic effects of CHA (10 nmol).

5 These results suggest that adenosine A1 receptors in the posterior hypothalamus have an inhibitory role in the central cardiovascular regulation and that these vasodepressive and bradycardic actions are modified by raised cAMP and by GABAB receptor inhibition.
Large‐scale biogeographic patterns of vascular plant richness in North America: an analysis at the generic level
Authors: Qian Hong
Published: March 2003

The richness pattern of native vascular plants in North America (north of Mexico) was studied at the generic level. North America was divided into thirteen geographical regions, which were latitudinally grouped into four horizontal zones (northern, north‐middle, south‐middle, and southern zones); and longitudinally grouped into three vertical zones (eastern, central, and western zones). The native vascular flora of North America consisted of 1904 genera in 235 families and eighty‐three orders. Along the latitudinal gradient, generic richness (in terms of the number of genera) showed a striking increase with decreasing latitude. The southern zone had more than four times as many genera as did the northern zone (with a difference of 1436 genera). 93.3% of genera in the northern zone also occurred in the southern zone. Along the longitudinal gradient, the central zone had the highest generic richness and the eastern zone had the lowest, but the difference in generic richness between the two zones was only sixty‐one genera. The western and eastern zones shared 60% or more of their genera. Generic richness of vascular plants in North America was highly correlated (r=0.965) to available environmental energy (expressed by annual potential evapotranspiration).
Comparison of Southern Appalachian high‐elevation outcrop plant communities with their Northern Appalachian counterparts
Authors: Wiser Susan K.
Published: March 2003

Abstract. Southern Appalachian high‐elevation outcrops harbour six regionally rare Northern Appalachian taxa usually considered relicts of a Pleistocene alpine flora. For five of the six taxa, minimum elevation in the south was 367–1113 m higher than in the north. While habitats compared between the two regions share only 9% of their total flora, individual plots had up to 70% of their species occurring in the opposite region. The northern affinity of southern outcrops increased with elevation, slope steepness, soil Cu, B and SO4 and decreased with potential solar radiation and soil Na. As a result, communities above 1600 m on felsic bedrock, and above 1350 m on mafic bedrock, were most northern in composition. Northern affinity of southern outcrops also increased with latitude, which may partly result from closer geographic proximity to past communities that provided progenitors for the current northern flora. Northern treeless habitats increased in southern affinity with increased slope steepness, perennial seepage, vegetation height, shade, soil pH, Al, Mn, Na and decreased elevation and organic matter. As a result, northern outcrop communities below treeline were most similar to those on southern outcrops. This suggests that southern outcrop vegetation may be more similar to Pleistocene outcrop vegetation than to Pleistocene alpine vegetation. Partial constrained ordination showed that while compositional differences between the Northern and Southern Appalachian habitats were largely explained by environmental differences, there was a significant component of residual variation explained by north or south position that was unrelated to environment. These residual compositional differences may result from historical influences on community structure involving stochastic extinction and colonization processes.
Soil properties and seedling establishment in soils from monodominant and high‐diversity stands of the tropical deciduous forests of México
Authors: Martijena Nora E.
Published: March 2003

Abstract. The hypothesis that soils from mature monodominant forests are unfavourable for establishment of tree species other than the dominant was tested for a lowland tropical deciduous forest with stands dominated by Celaenodendron mexicanum Standl. (CS). This species of Euphorbiaceae occurs almost exclusively in monodominant stands in which recruitment of other species appears to be poor. Soil properties were examined and experiments were conducted on germination and establishment of Celaenodendron mexicanum and three other species common in adjacent high‐diversity mixed stands (MS): Recchia mexicana Moc. & Sessé, Caesalpinia eriostachys Benth., and Cordia alliodora (Ruiz & Pav.) Oken. Soil moisture regimes are affected by topographic position in the study area, but Celaenodendron mexicanum was found occupying hillsides as well as flatlands, and slope gradients of its stands were typical of the region. The microsites occupied in relation to soil moisture and light availability also appear to be undistinctive. There were no significant differences between stand types in any soil property (pH, O.C., total N, total P, avail. P, K, Ca, Mg, Na, Mn, Fe, Cu, Zn concentrations). A stand of intermediate dominance of Celaenodendron (ICS) did not differ from its adjacent mixed stand (MS) in soil texture or most of the nutrients tested; however, seasonally restricted differences in the contents of Fe and Mn (ICS<MS) were detected. In fact, the contents of most nutrients in all the stands changed significantly between seasons: mostly, they were lower in the wet season.

Germination percentages and seedling survival to 4 months did not differ between CS and MS soils in greenhouse tests, and in field tests Caesalpinia eriostachys established in both stand types.

The results suggest that the distinction between monodominance and high diversity is not maintained by some simple physiological restriction on the establishment of new seedlings.
Models of large‐scale breeding‐bird distribution as a function of macro‐climate in Ontario, Canada
Authors: Venier L. A. , McKenney D. W. , Wang Y. , McKee J.
Published: March 2003

Aim We modelled the relationship of breeding evidence for five species of forest songbirds (ruby‐crowned kinglet (Regulus calendula) Blackburnian warbler (Dendroica fusca), black‐throated blue warbler (Dendroica caerulescens), bay‐breasted warbler (Dendrioca castanea) and Connecticut warbler (Oporornis agilis)) and a variety of macro‐climate variables to examine the importance of climate as a factor determining distribution of breeding in these species and to assess the usefulness of spatial predictions generated from these models.

Location Modelling was conducted over the entire province of Ontario, Canada, an area of ≈900,000 km2.

Methods Data on the distribution of breeding in the province was derived from the Breeding Bird Atlas of Ontario. We used logistic regression to model the relationship between the probability of breeding (assessed in 10 km×10 km blocks) and estimates of a variety of climate variables at the same scale. Models were selected that had the least number of explanatory variables while at the same time having close to the best possible classification accuracy.

Results The final models for these five species had from one to six explanatory variables and an overall concordance of 70.4% to 86.3% indicating a good classification accuracy. Results from subsampling 50% of the original data ten times indicate that (1) the classification accuracy of the model for data used to generate the model is not very sensitive to the specific observations used to generate the model (2) the classification accuracy of test data is close to the classification accuracy of the model data and (3) the classification accuracy of the test data is not dependent on the specific observations used to generate the model. We generated a spatial prediction of the probability of occurrence of each species for Ontario using the relationships defined by the logistic regression models and using 1 km gridded estimates of the necessary climate variables. These probability maps closely matched the maps of observed evidence of breeding from the Atlas.

Main conclusions Although mechanisms controlling breeding distribution cannot be determined using this method, we can conclude that (1) macro‐climate is an important factor directly and/or indirectly determining distribution of breeding in these species and (2) spatial predictions of probability of breeding are accurate enough to be useful in predicting probability of breeding in unsampled areas.
Testate amoebae and the fossil record: issues in biodiversity
Authors: Charman Dan J.
Published: March 2003

Biodiversity assessment is broadly divided into a consideration of species diversity, genetic diversity and ecosystem diversity. Individual species are readily defined for many groups of organisms and their relationship with fossil taxa found in the Late Quaternary is clear. Testate amoebae are a group of protozoa which form external tests that are preserved in peat and lake sediments. The higher taxa levels are defined by the morphology of the soft pseudopodia which are not preserved in fossil specimens but many lower taxa can be recognized by test characteristics. Two sets of problems occur in the assessment of fossil testate amoebae biodiversity, related to species definitions based on morphological criteria in living specimens, and the preservation and study of fossil tests. The biological species concept cannot be readily applied to testate amoebae and morphospecies are therefore defined on the basis of the characteristics of pseudopodia and tests. However, the accepted degree of intraspecific morphological variation appears to be variable between authorities and the number of described species is therefore poorly defined. In addition, there is likely to be no straightforward relationship between species diversity and genetic diversity. Further problems of species differentiation are encountered in fossil specimens so that the assessment of biodiversity in fossil populations is even more problematic. The variable results which can be obtained by the adoption of different sets of species definitions are illustrated with respect to fossil faunas from peat profiles in Canada and the UK. The biodiversity of living testate amoebae and other groups of lower organisms is poorly known and further consideration needs to be given to the definition and description of both living and fossil specimens if these problems are to be resolved. The assessment of complete ecosystem biodiversity is not possible without this and investigations which consider the role of diversity in ecosystem functioning cannot even begin.
Size and shape variability in relation to species differences and climatic gradients in the African rodent Oenomys
Authors: Renaud Sabrina
Published: March 2003

AimThe modern African murine rodent Oenomys is a semiarboreal genus characteristic of the rain forest zone. The size and shape geographical differentiation is studied in order to discuss the possible evolutionary patterns and constraints leading to this distribution.

LocationTwo species of Oenomys have been previously recognized, corresponding to the West African forest block on the one hand and to the main forest block on the other hand. Both species have been sampled, and forty localities permit the study of the whole geographical range of Oenomys, from Guinea to Kenya.

MethodsA Fourier analysis applied to the outlines of the first upper and lower molars allows a quantification of the size and shape variations across the geographical range of Oenomys.

ResultsThis morphometrical analysis defines three morphological groups of Oenomys, corresponding to the West, Central, and East African forest zone. This result suggests the existence of an additional cryptic species. The Western group is characterized by broad asymmetrical molars and a small size. The Central African group has more elongated and larger molars while the Eastern African group displays extremely constricted molars and a small size.

Main conclusion The shape can be considered as charactheristic of each group and its variations appear to be mostly related to phylogeny while size exhibits variations within each group related to climatic gradients. This discrepancy could be related to different genetic determinants for both characters, the shape being strongly genetically constrained while size can vary according to a wide range of environmental factors.
Insights into the processing of carbon in the South Florida Cypress Wetlands: a whole‐ecosystem approach using network analysis
Authors: Bondavalli Cristina , Ulanowicz Robert E. , Bodini Antonio
Published: March 2003

Aim

The aim of this research was to investigate the potential of the South Florida Cypress Wetlands as a carbon‐accumulating system.

Location

This ecosystem is part of the Big Cypress Natural Preserve, located in the south‐west part of Florida (USA) between the Mangrove Swamps that border the Gulf of Mexico and the Everglades.

Methods

This investigation was carried out by constructing networks of carbon exchange between the living and nonliving components that comprise this ecosystem. By means of these networks potential for carbon accumulation has been assessed by identifying and quantifying pathways for the transfer of carbon, assessing the efficiency between trophic levels, and evaluating the importance of material cycling. These analyses are commonly referred to as network analysis.

Results

Results obtained show that dependency on detritus by higher trophic levels is rather low and so is the trophic efficiency. Yet, less than 10% of the carbon that flows through the system is recycled and the magnitude of internal ascendency reaches only 40% of the total system ascendency.

Main conclusions

All these results support the hypothesis that the South Florida Cypress Wetlands are predominately flow‐through in nature and that carbon accumulation in this environment is noticeable.
Pollen‐based reconstructions of Japanese biomes at 0, 6000 and 18,000 14C  yr  bp
Authors: Takahara Hikaru , Sugita Shinya , Harrison Sandy P. , Miyoshi Norio , Morita Yoshimune , Uchiyama Takashi
Published: March 2003

A biomization method, which objectively assigns individual pollen assemblages to biomes ( Prentice et al., 1996
), was tested using modern pollen data from Japan and applied to fossil pollen data to reconstruct palaeovegetation patterns 6000 and 18,000 14C yr bp Biomization started with the assignment of 135 pollen taxa to plant functional types (PFTs), and nine possible biomes were defined by specific combinations of PFTs.

Biomes were correctly assigned to 54% of the 94 modern sites. Incorrect assignments occur near the altitudinal limits of individual biomes, where pollen transport from lower altitudes blurs the local pollen signals or continuous changes in species composition characterizes the range limits of biomes. As a result, the reconstructed changes in the altitudinal limits of biomes at 6000 and 18,000 14C yr bp are likely to be conservative estimates of the actual changes.

The biome distribution at 6000 14C yr bp was rather similar to today, suggesting that changes in the bioclimate of Japan have been small since the mid‐Holocene.

At 18,000 14C yr bp the Japanese lowlands were covered by taiga and cool mixed forests. The southward expansion of these forests and the absence of broadleaved evergreen/warm mixed forests reflect a pronounced year‐round cooling.
Juvenile tree growth rates and species sorting on fine‐scale soil fertility gradients in a Chilean temperate rain forest
Authors: Lusk Christopher H. , Matus Francisco
Published: March 2003

Aim

We sought to clarify the role of juvenile tree growth rates in species sorting along fine‐scale fertility gradients in the coast range forests of southern Chile.

Location

In montane forests in the coast range, the conifer Fitzroya cupressoides occupies the poorest soils, whereas dominance shifts to the evergreen angiosperms Nothofagus nitida and/or Weinmannia trichosperma on moderately infertile sites. On the most fertile sites, N. nitida is usually the sole overstorey dominant.

Methods

We examined the effects of soil depth and nitrogen availability on height growth and leaf nitrogen levels of the three common overstorey dominants. Sapling height growth rates and foliage nitrogen concentration were measured in 20 large gaps (>0.1 ha), on sites of varied soil depth and potential N‐mineralization rates.

Results

Height growth rates of Weinmannia and Nothofagus were strongly positively correlated with both soil depth and potential N‐mineralization. Height growth of Fitzroya was strongly correlated with soil depth, but not with N‐mineralization. Nothofagus and Weinmannia enjoyed large growth‐rate advantages over Fitzroya on the more fertile soils of the study area, and this advantage was reduced or nullified (but not reversed) on poor soils. This pattern was associated with species differences in nitrogen use: on fertile soils, Nothofagus and especially Weinmannia, achieved more height growth per unit of leaf N than Fitzroya, whereas differences were minimal on poor soils.

Main conclusions

Results suggest that comparative height growth rates of juvenile trees, associated with nitrogen productivity differences, play a key role in determining eventual dominance on productive sites, but that traits other than growth (possibly related to nutrient retention) are more important on low fertility sites. Disturbance regimes appear to vary in relation to site fertility, and differential species responses to this superimposed disturbance gradient are also probably influential in determining overstorey composition.
Biogeography of the southern cool‐temperate galaxioid fishes: evidence from metazoan macroparasite faunas
Authors: McDowall R. M.
Published: March 2003

Aim

This study seeks evidence for coevolution between the galaxioid fish families, Galaxiidae and Retropinnidae, and their macroparasites as a means of adding to our understanding of the biogeography of the fish families.

Location

These families are characteristic southern cool‐temperate elements in the fish faunas of Australia, New Zealand and southern South America and some southern/sub‐Antarctic islands.

Methods

The analysis is based on a review of the literature.

Results

Analysis showed that in each area fish species have parasites that are representative of the general fish parasite faunas of that area, rather than those characteristic of, or specific to, either these galaxioid families or the genera and species that they contain. In many instances the parasites also infect exotic fish species introduced into each area.

Main conclusions

There is little evidence that parasite faunas have coevolved with the fish hosts. Parasite data therefore provide little support for a vicariance biogeography of galaxioid fishes in the southern cool‐temperate region. Also, the data do not conflict with dispersal hypotheses for that biogeography.
A relict population of Fagus grandifolia var. mexicana at the Acatlan Volcano, Mexico: structure, litterfall, phenology and dendroecology
Authors: Williams‐Linera Guadalupe , Devall Margaret S. , Alvarez‐Aquino Claudia
Published: March 2003

Aim  Fagus grandifolia var. mexicana (Martinez) Little has an extraordinarily restricted distribution in the Mexican montane cloud forests. Isolated Fagus (beech) populations have been recorded in less than 10 small areas (2–40 ha) in the eastern Sierra Madre at altitudes from 1400 to 2000 m. The objectives were to determine tree and seedling age, forest structure, phenology, litterfall patterns and the relationship between mast and climatic variables.

Location  We report on three Fagus stands at the Acatlan Volcano, Veracruz, Mexico.

Methods  Changes in forest cover were determined using aerial photographs. Within each stand, basal area, density and tree species composition were determined in a 0.1‐ha band transect. Additionally, litterfall production was quantified and phenophases were recorded monthly over a 3‐year period, and 60 tree cores were collected to determine age distribution and tree‐ring growth.

Results  The forest was atypical in several respects. Fagus was the only dominant tree species in the crater stand, although in the rim and at the top of the volcano it was codominant with other tree species. Juveniles occurred only on the rim, but there was a seedling bank in the crater. Although forest cover in the area increased between 1968 and 1993, the Fagus stands did not change in size. Leaf production peaked in March and April, and leaf fall occurred from October through February. Litterfall production was the highest in November. During mast years, flowering started in February and between mast events there were no flowers or fruits. Minimum temperatures were highly correlated with Fagus litterfall and leaf fall. Seedlings ranged in age from 2 to 18 years and were 13–60 cm tall. Tree cores ranged from 76 to 120 years, but trees were older than the core samples.

Main conclusions  Although beech is considered a gap regeneration species that reaches the canopy after alternating periods of release and suppression, the trees in the crater were released when less than 1.5 m tall and have suffered few periods of suppression since. The results indicate that the crater stand was established after a severe disturbance destroyed the existing forest. We conclude that the relict beech population should be able to maintain itself, if not severely disturbed by humans or by climatic changes related to global warming.
Species richness and endemism in the Western Australian flora
Authors: Beard J. S. , Chapman A. R. , Gioia P.
Published: March 2003

Aim  Estimates of endemic and non‐endemic native vascular plant species in each of the three Western Australian Botanical Provinces were made by East in 1912 and Beard in 1969. The present paper contains an updated assessment of species endemism in the State.

Location  Western Australia comprises one third of the continental Australian land mass. It extends from 13° to 35° S and 113° to 129° W.

Methods  Western Australia is recognized as having three Botanical Provinces (Northern, Eremaean and South‐West) each divided into a number of Botanical Districts. Updated statistics for number of species and species endemism in each Province are based on the Census of Western Australian Plants data base at the Western Australian Herbarium (Western Australian Herbarium, 1998 onwards).

Results  The number of known species in Western Australia has risen steadily over the years but reputed endemism has declined in the Northern and Eremaean Provinces where cross‐continental floras are common. Only the isolated South‐West Province retains high rates of endemism (79%).

Main conclusions  With 5710 native species, the South‐West Province contains about the same number as the California Floristic Province which has a similar area. The Italian mediterranean zone also contains about this number but in a smaller area, while the much smaller Cape Floristic Region has almost twice as many native species. The percentage of endemic species is highest at the Cape, somewhat less in south‐western Australia and less again in California. Italy, at 12.5%, has the lowest value. Apart from Italy, it is usual for endemism to reach high values in the largest plant families. In Western Australia, these mainly include woody sclerophyll shrubs and herbaceous perennials with special adaptations to environmental conditions. While those life forms are prominent in the Cape, that region differs in the great importance of herbaceous families and succulents, both of which are virtually absent from Western Australia. In California and Italy, most endemics are in families of annual, herbaceous perennial and soft shrub plants. It is suggested that the dominant factor shaping the South‐West Province flora is the extreme poverty of the area’s soils, a feature that emphasizes sclerophylly, favours habitat specialization and ensures relatively many local endemic species.
The historical ecology of yellow perch (Perca flavescens[Mitchill]) and their parasites
Authors: Carney Joseph P. , Dick Terry A.
Published: March 2003

Aim  To determine the origins of the host–parasite association between among yellow perch (Perca flavescens[Mitchill]) and the parasites Crepidostomum cooperi Hopkins, Proteocephalus pearsei La Rue and Urocleidus adspectus Beverly Burton. Of secondary interest are the parasites Bunodera luciopercae (Muller) and Proteocephalus percae (Muller) predictably associated with the Eurasian perch.

Location  The areas considered are the Holarctic, since the upper‐Cretaceous, and contemporary North America.

Methods  Published and new information from host and parasite phylogenies, palaeontology, palaeogeography and plate tectonics and host biology is incorporated to assess the origins of yellow perch and several of its parasites. This information is used to determine the origins for these host–parasite associations.

Results  Cladistic analysis suggests a Laurasian origin for Percidae and Perca, and that Perca is sister to the other genera in the family. Parasite phylogenies support a North American origin for the three species associated with yellow perch and a Laurasian origin for B. luciopercae. Proteocephalus pearsei and P. percae are not sister taxa. The fossil record for Perca dates to the Miocene in Europe and the Pleistocene in North America. North America and Europe were connected across the North Atlantic since at least the upper Cretaceous with separation complete by the Miocene. Europe was separated from Asia by the Obik Sea from the late Cretaceous until the Oligocene. Western cordillera orogeny and its accompanying high rates of water flow and Pleistocene glaciation represent barriers to Perca dispersal.

Main conclusions  The origin of Perca in North America dates at least to the late Oligocene when North America and Europe were connected across the North Atlantic and Europe and Asia were separate landmasses, and does not result from Pleistocene dispersal across Beringia from Asia. The present disjunction of Perca species in North America and Europe is due to the vicariant separation of North America and Europe. Based on the available information, yellow perch and its parasites have a North America origin. The association between yellow perch and the parasites in all cases is a consequence of host switching from other sympatric host species in North America and is not explained by co‐speciation. Even the association between the host‐specific Urocleidus adspectus and yellow perch originated with a host switch and is not due to co‐speciation. The basis for this host switching is geographical and ecological sympatry, especially shared feeding habits, with other North American fish hosts.
Future eating and country keeping: what role has environmental history in the management of biodiversity?
Authors: Bowman D.M.J.S.
Published: March 2003

In order to understand and moderate the effects of the accelerating rate of global environmental change land managers and ecologists must not only think beyond their local environment but also put their problems into a historical context. It is intuitively obvious that historians should be natural allies of ecologists and land managers as they struggle to maintain biodiversity and landscape health. Indeed, ‘environmental history’ is an emerging field where the previously disparate intellectual traditions of ecology and history intersect to create a new and fundamentally interdisciplinary field of inquiry. Environmental history is rapidly becoming an important field displacing many older environmentally focused academic disciplines as well as capturing the public imagination.

By drawing on Australian experience I explore the role of ‘environmental history’ in managing biodiversity. First I consider some of the similarities and differences of the ecological and historical approaches to the history of the environment. Then I review two central questions in Australian environment history: landscape‐scale changes in woody vegetation cover since European settlement and the extinction of the marsupials in both historical and pre‐historical time. These case studies demonstrate that environmental historians can reach conflicting interpretations despite using essentially the same data.

The popular success of some environmental histories hinges on the fact that they narrate a compelling story concerning human relationships and human value judgements about landscape change. Ecologists must learn to harness the power of environmental history narratives to bolster land management practices designed to conserve biological heritage. They can do this by using various currently popular environmental histories as a point of departure for future research, for instance by testing the veracity of competing interpretations of landscape‐scale change in woody vegetation cover. They also need to learn how to write parables that communicate their research findings to land managers and the general public. However, no matter how sociologically or psychologically satisfying a particular environmental historical narrative might be, it must be willing to be superseded with new stories that incorporate the latest research discoveries and that reflects changing social values of nature. It is contrary to a rational and publicly acceptable approach to land management to read a particular story as revealing the absolute truth.
Geographical history of the central‐western Pacific black fly subgenus Inseliellum (Diptera: Simuliidae: Simulium) based on a reconstructed phylogeny of the species, hot‐spot archipelagoes and hydrological considerations
Authors: Craig Douglas A. , Currie Douglas C. , Joy Deirdre A.
Published: March 2003

Aim

With six new species of subgenus Inseliellum Rubtsov recently described, a revised reconstructed phylogeny based on morphology is required. Geological history of islands where Inseliellum occurs, plus a cladistic analysis and hydrological considerations, provide the basis for a reconstructed geographical history of the species.

Location

Inseliellum is widely distributed and occurs in Micronesia, Cook Islands and Polynesia. A single specimen is known from Tonga Islands.

Methods

Maximum parsimony criteria using PAUP*, plus cytological information, were used to arrive at a preferred phylogenic reconstruction. Island ages of the hot spot archipelagoes involved are well known. The phylogeny was then compared with the palaeogeology. Information on evolution of running water habitats as islands age was incorporated into the biogeography.

Results

Cladistic analysis of forty of the forty‐eight known Inseliellum species with Simulium (Nevermannia) neornatipes Dumbleton from New Caledonia and S. (Hebridosimulium) laciniatum Edwards from Fiji as outgroups, shows basal species and clades to be on widely separated older islands. In the Society Islands basal species are widely spread. Derived species, with morphological adaptations to deal with specialized habitats, are on younger islands (e.g. Tahiti), where a major species radiation has taken place. The reconstructed phylogeny indicates dispersal back to older islands, with minor subsequent species radiation.

Main conclusions

Palaeogeological evidence provides a basis for postulating that Inseliellum entered the western Pacific area some 20 Ma, with the possibility that it rafted eastwards on proto‐Tonga Islands to the edge of southern‐central Pacific. Older Cook Islands were present at that time. Movement into the Marquesas Islands was not earlier than 6 Ma and into the Society Islands perhaps 8–10 Ma. Basal species with generalized habitat requirements would have found suitable habitats (inferred from hydrological postulates) on leaves in the original, small shaded streams. With erosion and valley development, in particular on Tahiti, species radiated into specialized habitats such as cascades. Rich seston and high velocity probably drove reduction of filtering fans in some clades. With collapse of the caldera and formation of large rivers at c. 0.9 Ma, S. exasperans Craig and S. tahitiense Edwards adapted to deep, swiftly flowing water, all indicative that specialized habitat availability drove species radiation in Inseliellum. In the Society Islands, dispersal of derived species back to the oldest western islands was not possible because erosion has removed suitable habitats.
Aboriginal fires in monsoonal Australia from historical accounts
Authors: Preece Noel
Published: March 2003

Aim

Traditional management of fire in the world's savannas is of vital interest for contemporary management. This paper reviews the nineteenth century literature on Aboriginal application of fire in the Northern Territory of northern Australia, and relates the other studies of the historical record for the whole savanna region of northern Australia. The aim is to provide a comprehensive picture of historical traditional fire practices.

Location

Northern Australia tropical (monsoonal) savanna region.

Methods

All available journals of explorers in the nineteenth century in the Northern Territory were reviewed and analysed.

Results

Twenty‐five explorers' journals were identified and reviewed. Fifteen yielded information on aboriginal use of fire. Two hundred and six observations were recorded in the journals. Of these, 100 were of active landscape fires and fifty‐two were of burnt landscapes. Other observations were discarded as they did not contribute to the understanding of traditional use of fire. The results were generally consistent with other studies completed in Queensland and Western Australia.

Main conclusions

The historical record shows that Aboriginal people in the `Top End' of the Northern Territory of Australia commenced burning early in the dry season, within weeks of the last rains, and continued throughout the dry season. Burning stopped only when the wet season rains prevented further burning. Little if any wet season burning was carried out. This picture is at variance with a previous historical study for the Northern Territory, but consistent with that for the whole northern Australian savannas using equivalent historical sources. The findings are important for ecological management of the savannas of northern Australia. Recent deleterious changes to the biota and landscape have been attributed to recent changes from traditional fire regimes. A reinstatement of traditional practices is proposed.
Island biogeography and metapopulation dynamics of Bahamian ants
Authors: Morrison Lloyd W.
Published: March 2003

Aim

I examined the island biogeography and metapopulation dynamics of ants inhabiting two archipelagos of small Bahamian islands. Of particular interest were measurement and comparison of turnover rates, examination of variation in relative population abundances, and the effect of a hurricane force disturbance on the ant fauna of these small islands.

Location

Archipelagos of small islands in the central Exumas and near the northeast coast of Andros, Bahamas.

Methods

Ants occupying small islands were surveyed using tuna and honey baits. I surveyed ninety‐three islands in the Exumas in 1998 and fifty‐eight islands at Andros in 1999, to compare with earlier surveys in both regions. The proportions of baits occupied were used as a measure of relative population abundance. A subset of seventeen small islands in the Exumas was surveyed in 1999 in the aftermath of Hurricane Floyd.

Results

Mean annual relative turnover rates were low: <2.5% year−1 on a per island basis, and <7% year−1 on a per species basis. Rates of immigration and extinction were similar, although immigrations exceeded extinctions in some comparisons. Relative population abundances of the two most common ant species varied inversely with each other. One species revealed a strong positive correlation with recent rainfall, whereas another varied strongly inversely. No extinctions of ants occurred on the seventeen small islands surveyed after Hurricane Floyd.

Main conclusions

Ants were found to be ubiquitous in this system, occurring on almost all vegetated islands. Ant populations were persistent over the period of study, and species rarely became extinct or colonized islands. The few instances of turnover observed appeared to occur randomly with respect to physical island characteristics. The correlational data suggest an interaction of interspecific competition and precipitation affect relative population abundances. Ants were found to be resistant to hurricane‐force disturbances. In the short term (one decade), the ant fauna of these islands appears to be in a state of static equilibrium, although non‐equilibrial dynamics may better characterize the system over longer time periods (several decades).
Diversity and biogeography of southern African intertidal Acari
Authors: Procheş Şerban , Marshall David J.
Published: March 2003

Abstract Aim  The aims were (1) to describe the diversity and geographical distribution of the intertidal mite fauna of southern Africa, and (2) to show how species richness, endemism and geographical patterns of this fauna (comprising taxa of variable terrestrial ancestry) compare with typically marine faunas.

Location and methods  To assess intertidal mite diversity and endemism, records (published and unpublished) were compiled for a variety of habitats (mainly rocky shores and mangroves), between Swakopmund (Namibia) and Inhambane (Mozambique). The geographical study was based on a dedicated sampling programme from rocky shores, at nine localities between Elandsbaai (on the west coast) and St Lucia (on the east coast).

Results  Eighty‐two species of marine mite, from thirty‐three genera, are currently known from southern Africa. The majority belong to the earlier marine ancestral Halacaridae (forty‐eight species), with the Ameronothroidea and Hyadesiidae collectively comprising seventeen species. In constituting three faunistic provinces, corresponding with the west (Atlantic), south and east coast (Indian) regions, the mite fauna conforms with trends for the southern African marine fauna in general. Species richness was greatest in the southern province, which deviates from the general pattern of increase from west to east, but is similar to that of some invertebrate taxonomic groups.

Conclusions  Despite their relatively recent marine connections, marine mites show typical geographical distributions, comparable with those of other rocky‐shore biota in southern Africa. The marine faunistic provinces are ‘insular’ and apparently remain largely intact, across taxonomic groups and with increased taxonomic resolution.
Time in hospital
Authors: HOLLOWAY IMMY M. , SMITH PAM , WARREN JOY
Published: March 2003

• This article is based on research into patients' perceptions of being in hospital.

• Time, ordinarily taken for granted, becomes a significant problem for people in hospital.

• Patients seek control over time that they do not seem to have during their stay in hospital.

• They try to keep track of time and find ways of passing it, while believing that precious personal time is lost to them.

• The insight gained into differing perceptions of time and how patients coped with these can be used to reduce some of the tensions and negative aspects of the way time is experienced in hospital.
A survey of self‐neglect in patients living in the community
Authors: LAUDER WILLIAM
Published: March 2003

• Self‐neglect is a familiar concept to all community nurses. Nevertheless there have been few empirical studies undertaken in this area over the last 30 years.

• The study of self‐neglect has been hampered by inadequate conceptualization and a lack of theoretical frameworks.

• This article reports a study of patients who did and did not self‐neglect, drawn from district nursing caseloads.

• Patients with self‐neglect had lower levels of operable self‐care agency than patients in a comparison group.

• Only self‐neglecting patients had the nursing diagnoses `ineffective management of therapy' and `non‐compliance'.