bluuebunny/crossref_metadata_2025 huggingface dataset:
Antifungal activities of twoLactobacillus plantarumstrains againstFusariummouldsin vitroand in malting of barley
Authors: Laitila A. , Alakomi H-L. , Raaska L. , Mattila-Sandholm T. , Haikara A.
Published: March 2003

Aims: The Lactobacillus plantarum strains VTT E-78076 (E76) and VTT E-79098 (E98) were studied for their antifungal potential against Fusarium species. Methods and Results:In vitro screening with automated turbidometry as well as direct and indirect impedimetric methods clearly showed Lact. plantarum cell-free extracts to be effective against Fusarium species including Fusarium avenaceum, F. culmorum, F. graminearum and F.oxysporum. However, great variation in growth inhibition was observed between different Fusarium species and even between strains. The antifungal potential of Lact. plantarum E76 culture, including cells and spent medium, was also examined in laboratory-scale malting with naturally contaminated two-rowed barley from the crops of 1990–96. The growth of the indigenous Fusarium flora was restricted by the addition of Lact. plantarum E76 to the steeping water. However, the antifungal effect was greatly dependent on the contamination level and the fungal species/strains present on barley in different years. Conclusions:Lactobacillus plantarum strains E76 and E98 had a fungistatic effect against different plant pathogenic, toxigenic and gushing-active Fusarium fungi. Significance and Impact of the Study: The present study indicates that Lact. plantarum strains with known and selected characteristics could be used as a natural, food-grade biocontrol agent for management of problems caused by Fusarium fungi during germination of cereals.
Diversity among Bradyrhizobium isolates nodulating yardlong bean and sunnhemp in Guam
Authors: You Z. , Marutani M. , Borthakur D.
Published: March 2003

Aims: To isolate and characterize bradyrhizobia that nodulate yardlong bean and sunnhemp in Guam. Methods and Results: Bradyrhizobia populations that nodulate yardlong bean and sunnhemp in Guam were examined for genetic diversity and their relatedness to Bradyrhizobium japonicum and B. elkanii reference strains. Genomic DNA of 58 isolates of Bradyrhizobium spp. was hybridized with B. japonicum nodY and B. elkanii nodK genes. Based on the hybridization patterns, the isolates were classified into three nodY-nodK hybridizing groups. Group I comprised the majority of the isolates and hybridized with nodY whereas group II isolates hybridized with nodK. The group III isolates, that did not hybridize with either nodY or nodK, formed nitrogen-fixing nodules on cowpea but did not nodulate soybean. DNA sequence analysis of a 280-bp fragment of the variable region of the 16S rRNA gene of a few group III isolates showed that these isolates were more similar to Bradyrhizobium spp. than to B. japonicum or B. elkanii. Conclusions: The majority of the isolates nodulating yardlong bean and sunnhemp in Guam are similar to B. japonicum, although some isolates are similar to Bradyrhizobium spp. that nodulate a miscellaneous group of legumes including cowpea. Significance and Impact of the Study: Since both yardlong bean and sunnhemp are nodulated by a range of bradyrhizobia, selection of superior strains may be based on nodulation effectiveness on both legumes.
Characterization of the muscarinic receptor mediating contraction of the dog prostate
Authors: Fernández J. L. G. , Rivera L. , López P. G. , Recio P. , Vela‐Navarrete R. , García‐Sacristán A.
Published: March 2003

1 We have studied the effects of muscarinic cholinoceptor agonists and subtype‐preferring antagonists on the isometric contraction of smooth muscle strips from dog prostate.

2 Acetylcholine and carbachol induced contraction of prostate strips from the peripheral zone, (‘the capsule’). Bethanechol contracted the tissue but not at lower doses. McN‐A‐343 and oxotremorine‐M showed the same effects.

3 Blocking α‐ and β‐adrenoceptors with phentolamine and propranolol, respectively, did not modify carbachol‐induced contractions.

4 The nicotinic receptor blocker, hexamethonium (10−−6–10−−4 m) did not affect the contractile response evoked by a single dose of carbachol (10−−5 m), whilst the muscarinic receptor antagonist, atropine (10−−11–10−−9 m), inhibited it in a competitive manner.

5 The muscarinic M1 (pirenzepine), M2[AF‐DX 116, himbacine (M2/M4) and methoctramine], M3 (HHSID and f‐F‐HHSID), and putative M4 (tropicamide) antagonists reduced significantly the carbachol‐induced contractions. The pIC50 values were: atropine (10.01) > himbacine (8.3) > methoctramine (7.85) > AF‐DX 116 (7.60) > HHSID (7.21) > p‐F‐HHSID (7.10) > pirenzepine (7.30) > tropicamide (7.00).

6 The antagonist profile indicates that an predominant M2 receptor subtype could mediate the muscarinic contraction in the canine prostate.
Involvement of cyclic GMP‐dependent mechanism in the nitrergic relaxation of the bovine oesophageal groove
Authors: Barahona M. V. , Sánchez‐Fortún S. , San Andrés Md , Rodríguez C. , Andrés M. San
Published: March 2003

1 The present study was designed to investigate the mechanisms involved in the relaxations to nitric oxide (NO) of bovine oesophageal groove preparations suspended in organ baths for isometric tension recordings. In preparations treated with guanethidine (10−−5 m) and atropine (10−−7 m) to block adrenergic neurotransmission and muscarinic receptors, respectively, NO released from nitrergic nerves by electrical field stimulation (EFS, 0.5–16 Hz, 1 ms duration, 20 s trains) and exogenously applied as an acidified solution of sodium nitrite (NaNO2, 10−−6–10−−3 m) caused frequency‐and dose‐dependent relaxations of noradrenaline (NA, 10−−5 m)‐precontracted preparations.

2 Incubation with an inhibitor of NO‐stimulated soluble guanylate cyclase, 1H‐[1,2,4]oxadiazolo[4,3,‐a]quinoxalin‐1‐one (ODQ, 3 × 10−−6m, for 30 min) did not change the basal tension of oesophageal groove strips but inhibited relaxations to EFS and to exogenous NO.

3 Treatment with iberiotoxin (10−−7 m) and apamin (5 × 10−−7 m), which are blockers of large and small conductance Ca2+‐activated K+ channels, respectively, did not modify basal tension or the relaxations induced by EFS and exogenous NO. Incubation with iberiotoxin (10−−7 m) or apamin (5 × 10−−7 m) plus ODQ (3 × 10−−6 m) significantly reduced the relaxations to EFS and exogenous NO. However, in both cases the reductions were similar to the inhibition caused by ODQ alone. The combined addition of charybdotoxin (3 × 10−−8 m) and apamin (5 × 10−−7 m) did not change relaxations to EFS or exogenous NO of the bovine oesophageal groove.

4 The blocker of ATP‐sensitive K+ channels, glibenclamide (10−−6 m), had no effect on either resting tension or relaxations induced by both EFS and exogenous NO. Combined treatment with ODQ (3 × 10−−6 m) and glibenclamide (10−−6 m) did not produce additional inhibition compared to ODQ alone.

5 The present results indicate that NO acts as an inhibitory neurotransmitter by relaxing bovine oesophageal groove smooth muscle through a guanylate cyclase‐dependent mechanism which does not appear to involve the opening of K+ channels.
Response to isoprenaline of rabbit detrusor muscle following exposure to 5, 8, 11, 14 eicosatetraynoic acid. Role of prostanoids on beta‐adrenergic‐evoked response
Authors: Bolle Paola , Fidanza Stefano , Tucci Paolo
Published: March 2003

1 Incubation with indomethacin or ibuprofen causes a fall in basal tone and inhibits isoprenaline‐evoked response in rabbit detrusor muscle strips. To ascertain whether this is due to cyclo‐oxygenase inhibition, we investigated the influence on β‐adrenoceptor response of 5, 8, 11, 14 eicosatetraynoic acid (ETYA) which, unlike nonsteroidal anti‐inflammatory drugs, has no action in vitro other than cyclo‐oxygenase inhibition.

2 Incubation of detrusor strips with ETYA (7 or 14 μm) for 60 min significantly reduced tissue response to isoprenaline by an extent similar to that induced by indomethacin, but only slightly affected basal tone.

3 In tissues preincubated with indomethacin, the addition of PGE2 or PGE1 to restore basal tone, completely re‐established isoprenaline‐evoked responses.

4 Our findings in rabbit detrusor strips show that inhibition of cyclo‐oxygenase and of prostanoid production is the main mechanism involved in lowered β‐adrenoceptor evoked response.

5 In addition, these findings strengthen the conviction that ibuprofen and indomethacin act largely through mechanisms other than inhibition of prostanoid production.
Effects of natural tachykinins on porcine lower urinary tract smooth muscle
Authors: Bolle P. , Severini C. , Falconieri‐Erspamer G. , Tucci P. , Erspamer V.
Published: March 2003

1 The aim of our study was to ascertain the possible differences and/or similarities in natural tachykinin activity in vitro on lower urinary tract of large‐sized animals as compared with data obtained in laboratory animals.  2 Besides tachykinins normally present in mammals, namely substance P (SP), neurokinin A (NKA) and neurokinin B (NKB), we tested non‐mammalian tachykinins, such as eledoisin (ELED), physalaemin (PHYS), kassinin (KASS) and PG‐kassinin II (PG‐KASS II).  3 NKA, KASS and ELED were found to be the most potent peptides in contracting detrusor strips from porcine bladder. In particular, NKA showed a pD2 of 7.14, whereas KASS and ELED showed pD2 values of 7.20 and 7.22, respectively. The activity of NKB and PG‐KASS II corresponded to 72.4 and 55.0% respectively of that of NKA. SP and PHYS activity corresponded to only 2% of that of NKA.  4 NKA (pD2 7.92) was the most active peptide in contracting bladder neck tissues as well. ELED and KASS were found to have lower, similar pD2 values (7.62 and 7.70, respectively), whereas NKB and PG‐KASS II were much less active (pD2 7.12 and 6.74, respectively). Moreover, SP and PHYS showed an activity range lower than 2% of that of NKA.  5 The reported results confirm that, on pig vesical neck and detrusor, NK1 receptors represent a minority as compared with NK2 and NK3 receptors. By contrast, the presence of NK2 receptors is demonstrated by a greater potency of NKA. The presence of NK3 receptors both on detrusor and neck is evidenced by NKB activity and by results achieved with PG‐KASS II.
Sensory neuropeptides are not involved in acetaldehyde‐induced bronchoconstriction in guinea‐pigs
Authors: Myou S. , Fujimura M. , Kita T. , Katayama N. , Abo M. , Yoshimi Y. , Nishitsuji M. , Nomura S. , Nakao S.
Published: March 2003

1 Alcohol‐induced asthma is characterized by worsening of asthmatic symptoms after alcohol ingestion. Acetaldehyde, a metabolite of ethanol, is thought to be a main factor of alcohol‐induced asthma. Although airway sensory nerves are known to be activated in asthma, there have been no studies investigating the role of tachykinins in the airway response to acetaldehyde. The purpose of the present study was to evaluate the involvement of tachykinins on acetaldehyde‐induced bronchoconstriction in guinea‐pigs.

2 After capsaicin desensitization or intravenous administration of 10 mg kg–1 FK224, a NK1 and NK2 dual antagonist, airway responses to ascending doses (2.5–20 mg ml–1) of inhaled acetaldehyde was examined using a modified Konzett–Rössler method in guinea‐pigs.

3 Inhalation of acetaldehyde induced bronchoconstriction in a dose‐dependent manner. The FK224 failed to reduce the acetaldehyde‐induced bronchoconstriction. Pretreatment with capsaicin did not alter the bronchoconstriction induced by acetaldehyde at a dose of 2.5–10 mg ml–1. Pretreatment with capsaicin slightly, but significantly, inhibited bronchoconstriction induced by 20 mg ml–1 of acetaldehyde.

4 The present results suggest that tachykinins are not involved in acetaldehyde‐induced bronchoconstriction in guinea‐pigs.
Historical biogeography ofEusattus muricatus(Coleoptera: Tenebrionidae) within the Great Basin, western North America
Authors: Epps Tammy , Britten Hugh , Rust Richard
Published: March 2003

Genetics ofEusattus muricatusLeConte (Coleoptera: Tenebrionidae) populations within the Lahontan Basin and the Lahontan Trough of the Great Basin, western North America were assayed using protein electrophoresis. Two similar population phenograms were developed using neighbour‐joining and maximum likelihood algorithms. An area cladogram was developed using geological data. Maximum likelihood phenogram and area cladogram were compared to test for congruence between geology and phylogeny. Pairwise regressions of estimated gene flow measures (Nm) yielded a significant relationship for populations within the Lahontan Basin but not for the Lahontan Trough. Protein molecular clock calculations showed that populations within the Lahontan Basin were primarily differentiating according to the dune/subbasin isolation events predicted by the area cladogram.
Regional enrichment of predacious water beetles in temporary ponds at opposite east–west ends of the Palearctic
Authors: Kholin Sergey , Nilsson Anders
Published: March 2003

Regional and local species richness of temporary pond dytiscid water beetles were compared among three regions within the Palearctic: (1) Sweden in north west Europe, (2) Primorye and (3) Sakhalin Island in the Russian Far East. Both local and regional species richness were highest in Sweden and lowest in Sakhalin. Regional species richness was calculated from literature and collecting data for each region and for nested parts of regions. Local species richness was estimated from standardized net samples from fourteen or fifteen ponds in each region. Two different rarefaction techniques applied to the net‐sample data confirmed the observed interregional differences in species richness. Partial least square regression showed that pond area, depth and temperature affected local species richness positively in each region, whereas increasing shade and drought frequency had negative effects. Residuals from the regression analysis were positive in Sweden, negative in Sakhalin, and near zero in Primorye ponds. Consequently, the local species richness was related positively to regional species richness also when compensated for differences in the local pond environment. This was verified when pond species richness of each region was correlated with principal component scores representing a combination of pond area, depth and temperature. The species’ distributions among ponds displayed significantly nested patterns in Sweden and Sakhalin. However, species were significantly sorted along the pond area gradient only in Sweden. It is concluded that the observed interregional differences in local species richness are best explained by the accompanying gradient in regional species richness, lending support to the hypothesis of regional enrichment. Selected historical and ecological explanations for the observed differences in regional species richness are discussed.
Pattern in the distribution of Britain's upland breeding birds
Authors: Stillman R. A , Brown A. F.
Published: March 2003

We use a quantitative approach to identify fifty‐eight species of birds which breed in association with the British uplands. Similarities and differences between this list of ‘upland birds’ and previous more subjective lists are discussed. We then study pattern in the distribution of these species throughout the uplands. A high degree of regionalization is found, and interpreted in terms of the habitat composition of different regions, and known bird–habitat associations. Different regions differ widely, not only with respect to their bird species composition, but also in the number and conservation importance of their upland bird assemblages. In particular, we contrast the uplands of Wales and England with those of Scotland. The Welsh and English uplands contain a relatively low number of upland bird assemblages and are divided into a few large regions, each dominated by a single assemblage type. In comparison, the Scottish uplands are more varied, both in terms of the total number of assemblages, and the range of assemblages found at a small scale. The study provides a means of viewing any upland region within the national context.
Forest response to climate changes in Atlantic Equatorial Africa during the last 4000 years BP and inheritance on the modern landscapes
Authors: Vincens Annie , Schwartz Dominique , Elenga Hilaire , Reynaud‐Farrera Isabelle , Alexandre Anne , Bertaux Jacques , Mariotti André , Martin Louis , Meunier Jean‐Dominique , Nguetsop François , Servant Michel , Servant‐Vildary Simone , Wirrmann Denis
Published: March 2003

This review paper synthesizes the recent published palaeoecological results obtained in Atlantic Equatorial Africa (ECOFIT program) on the history of forest ecosystems and inferred climate changes during the past 4000 years. Evidence are mainly provided by pollen analysis carried out at nine sites from Congo, Cameroon and Ghana, locally supported by macroflora remains, phytoliths, diatoms, δ13C and mineralogical data.

At all the sites, except Lake Bosumtwi (Ghana), following a large expansion of rain and mesophilous forests until 3000 years BP, a major change is registered, affecting floristic composition, structure and geographical distribution. According to the hydrological sensitivity of the different sites, local openings of the forests with development of heliophilous formations and/or isolated enclosed savannas are observed at the most humid sites; complete disappearance of forested formations at the driest. The agreement between pollen records, hydrological and hydrobiological data definitely demonstrates that an arid event has been the primary driving factor of this change and is responsable for the main features of the modern landscapes in Atlantic Equatorial Africa. Moreover, the most recent palaeoecological data obtained in Congo (Lake Sinnda), indicate that this Late Holocene increasing aridity was of longer duration, from 4000 to 1300 years BP, and more progressive than previously inferred. A new expansion of forests is locally detected c. 900–600 BP despite increased human impact.
Reconstruction of adaptive radiation in insular habitats using integrated biogeographic information
Authors: Knox E. B.
Published: March 2003

AimTo develop an analytical method for accurately reconstructing the biogeographic events associated with adaptive radiation in a system of insular habitats.

LocationAn idealized, two‐dimensional model system of insular habitats is based on the altitudinally stratified vegetation zones on the island‐like mountains of eastern Africa.

MethodsThe model system is treated as a two‐dimensional array of insular habitats, and adaptive radiation is treated as a ‘space‐filling’ process according to six premises based on uniformitarian principles. Previous approaches to this class of problems have used (1) Hennig's progression rule, (2) optimization of biogeographic character states, and (3) reasoned argumentation with an intuitive synthesis of information. The strengths and limitations of these previous approaches are evaluated.

ResultsA closed analytical method is presented that accurately reconstructs biogeographic events. This methodological approach integrates atomized information back up to the appropriate level of biological organization and has general applicability to phylogenetic analysis.

Main conclusionsIn a truly evolutionary approach to phylogenetic systematics and biogeography, the initial analysis of the pattern of descent should be complemented with a subsequent analysis of the pattern of modification. The method presented here offers one approach to analysing the pattern of modification, which in this case constitutes biogeographic movement.
Structure, floristic composition and natural regeneration in the forests of Cat Tien National Park, Vietnam: an analysis of the successional trends
Authors: Blanc L. , Maury‐Lechon G. , Pascal J.‐P.
Published: March 2003

The forests in Cat Tien National Park, appear as a mosaic of different communities, distinct from each other with respect to their floristic and structural parameters. The objectives of this study are (1) to characterize the different formations occurring in the lowland part and (2) to identify the main successional trends in the area. Understanding forest succession is important for silviculture and restoration of forests and land rehabilitation, as adequate information on the ecological role of local species in the functioning of the forests is not available in Vietnam. Five plots (1 ha each) were established in the lowland part of Cat Tien National Park, where all the trees ≥ 10 cm d.b.h. (diameter at breast height) were located, measured and identified. A systematic sampling was made to assess the regeneration. Three plots (A, C and D) can be considered as secondary forests on the basis of their structural parameters. Plots A and C are dominated by Lagerstrmia calyculata and plot D by Dipterocarpus alatus. The other two plots can be regarded as mature forests. Plot B corresponds to a semideciduous formation dominated by Lagerstrmia calyculata and Fabaceae species, and plot E to an evergreen one dominated by dipterocarp species. The floristic composition of plots A and C will change in the future because dominant canopy species are rare or absent in regeneration. A correspondence analysis performed on the number of trees per species shows two kinds of successional trends: one from A to B on shallow and drier soils, and another from C to E on deeper and wetter soils.
The relative importance of trees versus lianas as hosts for phytophagous beetles (Coleoptera) in tropical forests
Authors: Ødegaard Frode
Published: March 2003

AimInsect assemblages associated with lianas in tropical forests are poorly studied compared with those associated with trees. The importance of lianas for the maintenance of local species richness of insect herbivores in tropical forests is therefore poorly understood. With this in mind, a comparative study of the relative importance of trees and lianas as hosts for phytophagous beetles was carried out.

LocationThe study area was located in the canopy of a dry tropical forest in Parque Natural Metropolitano, Panama province, Republic of Panama.

MethodsA crane system was utilized to access the canopy. The number of species and host specialization of adult phytophagous beetles associated with twenty‐six liana species of ten different families, and twenty‐four tree species of twelve different families were compared.

ResultsA total of 2561 host associations of 697 species of beetles were determined (1339 for trees and 1222 for lianas). On average 55.8 ± 6.8 beetle species were found to be associated with each tree species while the comparable number for lianas was 47.0 ± 6.1.

The pooled numbers of phytophagous beetle species associated with trees and lianas, respectively, were not significantly different. However, there were significantly more species feeding on green plant parts on lianas than on trees, and there were significantly more wood eaters on trees than on lianas.

Phytophagous beetles associated with lianas were significantly more specialized than the tree associates due to a higher degree of specialization among the species feeding on green plant parts of lianas. Wood eaters and flower visitors showed no differences in host specialization on different growth forms.

Main conclusionThe present study shows that lianas are at least as important as trees for the maintenance of local species diversity of phytophagous beetles at this site. The mechanisms that drive the patterns can only be hypothesized. Plant architecture, size, and length of growing season are probably involved. Further studies, should include measurements of plant traits to elucidate experimentally what mechanisms that drive the patterns. Additional insight would come from similar studies in other forest types, and also studies of other major taxonomic groups of arthropod herbivores.
Long‐term change in the floristic composition and vegetation structure of Carnac Island, Western Australia
Authors: Abbott Ian , Marchant Neville , Cranfield Ray
Published: March 2003

Aim To document changes in the floristic composition and vegetation structure of Carnac Island during a period of 40 years. This paper presents a synthesis of all available floristic and vegetational information.

Location Carnac Island is 8 km offshore from Fremantle, south‐west Western Australia.

Methods Comparison of lists of plant species for 1951, 1958/9, 1966/7, 1975/6 and 1995–6. Comparison of vegetation, based on structural and floristic elements, for 1951, 1965, 1972, 1984 and 1995.

Results Floristic composition (both native and exotic species) changed most dramatically in the period 1975/6–1995/6, with a 37% reduction in number of plant species. The number of annual and perennial native species present in 1995/6 was most similar to that in 1951. The most remarkable change in the flora has been the increase in annual exotic species since 1951. Immigration and extinction rates were greatest in the periods 1951–58/9 and 1958/9–1966/7, respectively. Vegetation structure has also altered, involving a reduction in height of dominant species from 3–4 m to 1 m as Acacia rostellifera and Olearia axillaris have declined in distribution. The weed species Mesembryanthemum crystallinum (first recorded 1975) and Malva parviflora (1958) now dominate the vegetation of half the island.

Main conclusions Five factors are considered to have contributed to botanical change: nesting seabird populations, eradication of the rabbit in 1969, drought, increased saltload from occasional cyclones in summer or autumn, and competition from increasing dominance of several weed species. Several of these factors have operated in opposing ways with respect to plant species richness and vegetation cover. Experimental studies are required to determine the strength of these interactions. Two weed species, Zantedeschia aethiopica (first recorded 1966) and Lycium ferocissimum (1992) have the potential to dominate the vegetation of the island.
Last glacial maximum biomes reconstructed from pollen and plant macrofossil data from northern Eurasia
Authors: Tarasov P. E. , Volkova V. S. , Webb T. , Guiot J. , Andreev A. A. , Bezusko L. G. , Bezusko T. V. , Bykova G. V. , Dorofeyuk N. I. , Kvavadze E. V. , Osipova I. M. , Panova N. K. , Sevastyanov D. V.
Published: March 2003

Pollen and plant macrofossil data from northern Eurasia were used to reconstruct the vegetation of the last glacial maximum (LGM: 18,000 ± 2000 14C yr bp) using an objective quantitative method for interpreting pollen data in terms of the biomes they represent (
Prentice et al., 1996
). The results confirm previous qualitative vegetation reconstructions at the LGM but provide a more comprehensive analysis of the data.

Tundra dominated a large area of northern Eurasia (north of 57°N) to the west, south and east of the Scandinavian ice sheet at the LGM.

Steppe‐like vegetation was reconstructed in the latitudinal band from western Ukraine, where temperate deciduous forests grow today, to western Siberia, where taiga and cold deciduous forests grow today. The reconstruction shows that steppe graded into tundra in Siberia, which is not the case today.

Taiga grew on the northern coast of the Sea of Azov, about 1500 km south of its present limit in European Russia. In contrast, taiga was reconstructed only slightly south of its southern limit today in south‐western Siberia.

Broadleaved trees were confined to small refuges, e.g. on the eastern coast of the Black Sea, where cool mixed forest was reconstructed from the LGM data.

Cool conifer forests in western Georgia were reconstructed as growing more than 1000 m lower than they grow today. The few scattered sites with LGM data from the Tien‐Shan Mountains and from northern Mongolia yielded biome reconstructions of steppe and taiga, which are the biomes growing there today.
Interactive effects of land use and other factors on regional bird distributions
Authors: Allen Andrew P. , O’Connor Raymond J.
Published: March 2003

Aim

We assessed the independent and interactive effects of land use and other factors on regional distributions of lake shore bird assemblages.

Location

Analyses were restricted to lakes of the northeastern United States (New England, New York, New Jersey).

Methods

Lake shore bird and habitat data were collected from a regional sample of 186 lakes between 1991 and 1995. Local and regional gradients in environmental attributes of the lakes and their watersheds, and in bird species composition, were characterized using detrended correspondence analysis. Bird assemblages were also characterized with respect to species diversity, total bird abundance, and absolute and proportional abundance for neotropical migrants, omnivores and tree foragers. The assemblage measures were compared with the environmental gradients and with the environmental variables from which those gradients were derived using correlations, linear regression and bivariate plots.

Results

Anthropogenic variables (e.g. human density) and nonanthropogenic variables (e.g. climate, forest composition, lake productivity) were highly confounded regionally, reflecting the influence of climate and geomorphology on land use and, in turn, the influence of land use on the environment. Moving south along the regional gradient to watersheds with more intensive land use, changes in bird assemblage structure were consistent with anthropogenic effects on the avifauna attributable to forest fragmentation: total bird abundance increased, fragmentation‐tolerant species were encountered more frequently, the proportional abundance of omnivores increased and the proportional abundances of tree foragers and neotropical migrants decreased. Bird diversity, as assayed using rarefaction, peaked at an intermediate position along the regional gradient, as did the absolute abundances of tree foragers and migrants.

Main conclusions

We propose that some community attributes peaked at an intermediate position along the regional gradient as a result of the interactive effects of land use and other factors on this region’s avifauna, with broad‐scale anthropogenic factors constraining assemblages on the urbanized lakes, and climate or other nonanthropogenic factors constraining assemblages on the pristine lakes. Anthropogenic and nonanthropogenic factors of similar scale and magnitude thus acted in concert to shape regional bird distributions.
Spatial variation and biogeography of sand forest avian assemblages in South Africa
Authors: Van Rensburg Berndt J. , Chown Steven L. , Van Jaarsveld Albert S. , McGeoch Melodie A.
Published: March 2003

Aim To examine biogeographical affiliations, habitat‐associated heterogeneity and endemism of avian assemblages in sand forest patches and the savanna‐like mixed woodland matrix.

Location Two reserves in the Maputaland Centre of Endemism (MC) on the southern Mozambique Coastal Plain of northern KwaZulu‐Natal, South Africa.

Methods Replicated surveys were undertaken in each of the two habitat types in each reserve, providing species abundance data over a full year. Vegetation structure at each of the survey sites was also quantified. Differences between the bird assemblages and the extent to which vegetation structure explained these differences were assessed using multi‐variate techniques. Biogeographical comparisons were based on species presence/absence data and clustering techniques.

Results Bird assemblages differed significantly between habitats both within a given reserve and between reserves, and also between reserves for a given habitat. Differences in vegetation structure contributed substantially to differences between the avian assemblages. Of the four species endemic to the MC, three (Neergaard’s sunbird, Rudd’s apalis, and Woodward’s batis) were consistently present in sand forest. The fourth (pink‐throated twinspot) preferred mixed woodland. None of these endemic species was classed as rare. In the biogeographical analysis, both the sand forest and the mixed woodland bird assemblages were most similar to bird assemblages found in the forest biome or the Afromontane forest biome, depending on the biome classification used.

Main conclusions The close affinities of sand forest and mixed woodland assemblages to those of the forest biome are most likely due to similarities in vegetation structure of these forests. Bird assemblages differ between the sand forest and mixed woodland habitats both within a given reserve and between reserves, and also between reserves for a given habitat. These differences extend to species endemic to the MC. Thus, conservation of sand forest habitat in a variety of areas is necessary to ensure the long‐term persistence of the biota.
Molecular biogeography of the Mediterranean lizards Podarcis Wagler, 1830 and Teira Gray, 1838 (Reptilia, Lacertidae)
Authors: Oliverio Marco , Bologna Marco A. , Mariottini Paolo
Published: March 2003

Aim  We discuss biogeographical hypotheses for the Mediterranean lizard species Podarcis and Teira within a phylogenetic framework based on partial mitochondrial DNA sequences.

Methods  We derived the most likely phylogenetic hypothesis from our data set (597 aligned positions from the 12S rDNA and phenyl tRNA) under parsimony, distance and maximum likelihood assumptions.

Results  The species usually included in Teira do not form a strongly monophyletic clade. In contrast, the monophyly of the genus Podarcis is rather well supported. Seven lineages are identified in the genus; in order of appearance within the tree, these are: the Balearic pityusensis and lilfordi pair, the sicula complex, a Tyrrhenian tiliguerta and raffonei pair, muralis, the Siculo‐Maltese filfolensis and wagleriana pair, the Balkan group (erhardi, peloponnesiaca, milensis, melisellensis and taurica), and the Ibero‐Maghrebian group (bocagei, atrata, hispanica and vaucheri).

Conclusions  The origin of the three European genera of lacertid assayed (Lacerta, Teira and Podarcis) is hypothesized to have occurred in the Oligocene. For Podarcis, a possible scenario of a Miocene diversification is derived from the sequence data, and the zoogeography of the lineages are discussed in relation to the palaeogeography of the Mediterranean. It is hypothesized that in the early history of the genus the main lineages separated by rapid, numerous and close events that produced a starting point very similar to a polytomy, hard to resolve by parsimony analysis of the data set.
Patterns in the distribution, composition and diversity of diatom assemblages in relation to ecoclimatic factors in Arctic Lapland
Authors: Weckström J. , Korhola A.
Published: March 2003

Aim

Relationships between diatom distribution, composition, species richness and environmental variables in lakes in Arctic Lapland were explored with particular attention to temperature.

Location

Transect in northern Fennoscandia (66°92–69°27) spanning boreal coniferous forest to treeless tundra along an altitudinal gradient of 108–1024 m a.s.l.

Methods

Surface‐sediment diatom assemblages and 22 physical and chemical limnological variables from 64 lakes were determined. Ordination techniques (PCA, DCA, CCA) and associated Monte Carlo permutation tests were used to identify the main environmental parameters controlling the distribution of the diatom taxa. Temperature optima and tolerances were estimated by weighted averaging (WA) regression. Diversity indices and cluster analysis were used to discover patterns in biodiversity and composition of diatom assemblages along the vegetational and altitudinal gradients.

Results

A total of 370 diatom taxa representing 40 genera were recorded, most of which were periphytic species. Lake‐water pH, calcium, sediment organic content, mean July temperature, and total organic carbon (TOC) were identified as the most important environmental variables in explaining the diatom distributions. Lakes located in the middle of the temperature gradient (i.e. mountain birch woodland in the ‘forest–tundra’ transition zone) was found to have the highest species diversity. The temperatures at around 13 °C (≈ 300 m a.s.l) and at around 9.5 °C (≈ 750 m a.s.l.) were identified as the major biotic boundaries.

Main conclusions

Our results indicate that distribution, composition and species diversity of diatoms are markedly regulated by temperature and other climate‐related factors in ecotonal waters. Ecological boundary areas are highlighted as important areas for maintaining biodiversity. The overall results lend support to the concept of ‘aquatic ecotone’.
Floristic analysis of vascular plant genera of North America north of Mexico: spatial patterning of phytogeography
Authors: Qian Hong
Published: March 2003

Aim

This paper aims at determining and quantifying phytogeographical relationships between North America and the rest of the world at the regional level and identifying possible patterns of regional differentiation in phytogeographical relationships, particularly along latitudinal and longitudinal gradients.

Location

North America north of Mexico.

Methods

North America north of Mexico was divided into twelve geographical regions arrayed in a grid with three divisions east‐to‐west by four divisions north‐to‐south. Based on the similarity of their world‐wide geographical distribution patterns, a total of 1904 indigenous genera of vascular plants found in North America north of Mexico were grouped into ten phytogeographical elements. Phytogeographical relationships of the twelve geographical regions of North America north of Mexico to the world flora were examined, based on the composition of phytogeographical elements. Multivariate analyses were used to determine the phytogeographical relationships.

Results

Along a latitudinal gradient from the Arctic to tropical North America, the proportions of the cosmopolitan and holarctic genera markedly increased, whereas the pantropical, amphi‐Atlantic tropical, neotropical and North American endemic genera strikingly decreased. Along a longitudinal gradient from the Atlantic coast to the Pacific coast, the proportions of the pantropical, amphi‐Pacific tropical, neotropical and North American–eastern Asian genera tended to decrease, whereas the North American–South American and North American endemic genera tended to increase.

Main conclusions

The spatial patterns of the phytogeography of North America could be to a large degree interpreted by the different effects of the direct land connections between North America and Eurasia and South America on intercontinental migration and by the different effects of regional geographical settings within North America on the speciation, dispersal and extinction of plant species.
Establishment patterns of exotic birds are constrained by non‐random patterns in introduction
Authors: Blackburn Tim M. , Duncan Richard P.
Published: March 2003

Aim

Species transported to and introduced into non‐native environments, termed ‘introductions’, constitute a growing component of many regional floras and faunas, yet not all such species successfully establish. Investigations into why some introductions succeed while others fail are often based on analyses of the outcome of historical introductions. Such ‘experiments in nature’ have the drawback that the effects of interest may be confounded because they have not been randomized with respect to each other, and because the species and locations chosen for introduction may not be a random subset of the available species or locations. Our aim is to quantify this non‐randomness using a global data set of bird introductions, and examine the factors associated with introduction probability in two subsets of these data, one taxonomic (order Anseriformes) and one geographical (British birds).

Location

Global.

Methods

Statistical analyses of the distributions among taxa and locations for 1378 introduction events for 426 bird species across the world, and statistical analyses of the characteristics of Anseriform and British bird species selected for introduction.

Results

Global introductions of birds have been highly non‐random with respect to taxon, location of origin, and location of introduction. Most introductions involve species in just five families (Phasianidae, Passeridae, Psittacidae, Anatidae and Columbidae), and most introductions have been to temperate and island locations. Within the taxonomic and geographical subsets, the species chosen for introduction tend to be abundant species that would have been relatively easy to obtain.

Main conclusions

The characteristics of the species and locations chosen for introduction are not representative of species and locations in general, which limits our ability to draw general conclusions from historical records, and generates problems of confounding and non‐independence in statistical analyses of introduction success. We suggest possible solutions for these problems.
A comparison of a discovery‐based and an event‐based method of historical biogeography
Authors: Brooks Daniel R. , McLennan Deborah A.
Published: March 2003

Aim

The event‐based method Dispersal‐Vicariance Analysis (DIVA) is compared with the discovery‐based method Brooks Parsimony analysis (BPA).

Location

South‐western USA, Mexico and northern Central America.

Methods

Results of DIVA of phylogenetic trees for six clades of birds inhabiting seven areas in the south‐western US, Mexico and northern Central America are compared with those of BPA for the same data set.

Results

Both approaches identify the same vicariant elements but differ in the way they treat dispersal. DIVA places such elements in one general ‘dispersal’ category, while BPA identifies different forms of dispersal, including peripheral isolates speciation (speciation by dispersal), post‐speciation dispersal, non‐response to a vicariance event, secondary contact between congeners (and the potential for reinforcement completing speciation) and potential extinction resulting from competition between a resident and a colonizing congener.

Main conclusions

BPA is more sensitive than DIVA with respect to the different possible manifestations of geographical dispersal. Despite substantial dispersal, avian communities in these areas manifest substantial historical structuring.
Distribution, abundance and biomass of epiphyte‐lianoid communities in a New Zealand lowland Nothofagus‐podocarp temperate rain forest: tropical comparisons
Authors: Hofstede Robert G. M. , Dickinson Katharine J. M. , Mark Alan F.
Published: March 2003

Aim

In tropical rain forests, epiphytes can contribute significantly to species diversity and biomass, a feature not generally associated with temperate forest systems. This study investigates epiphyte‐liane diversity and biomass on three host trees (two Dacrycarpus dacrydioides [Podocarpaceae] and one Nothofagus menziesii [Fagaceae]).

Location

These trees were of varying architecture on different sites in a New Zealand lowland temperate rain forest at 45°43′ S.

Methods

Cover of epiphytic and lianoid species (vascular and non‐vascular) was recorded in 5 m vertical height segments (trunk), on four aspects (north, south, east and west); and in four sections (inner, middle, outer branches and branch extremes) on four branch faces (positions: topside, both sides, underside) on each tree. Inclination, branch face, and diameter of branch/trunk substrate, height above ground, duff thickness, and location on tree (trunkfoot, main trunk, inner branches, middle branches, outer branches, branch extremes) were all recorded in 359 samples. Epiphytic biomass was derived for one tree.

Results

Sixty‐one vascular and ninety‐four non‐vascular taxa were recorded. Eight communities associated with the highly vegetated inner branches and main trunk, and seven indicative of the less vegetated middle to outer branches and branch extremes were recognized. Thirteen of the fifteen communities were present on a forest interior D. dacrydioides tree, nine on a riverside D. dacrydioides tree and seven on a N. menziesii tree. Most of the seven measured environmental variables were statistically significant in relation to ordination analyses of the samples. Dry mass per unit area and dry bulk density recorded were 350 ± 125 and 118 ± 13 g dm–2, respectively (trunkbase), and 206 ± 21 and 91 ± 4 g dm–2, respectively (inner and middle branches combined).

Main conclusions

Epiphytic community analyses that do not include non‐vascular flora either as generalized categories or as individual taxa are incomplete. Values for epiphytic dry weight for the trunkfoot of one tree appear to exceed comparable figures recorded from tropical rain forest systems. Epiphytic communities and biomass within at least some temperate rain forests can be validly compared with those of tropical rain forests.
Geographic distribution and population size of the mountain tapir (Tapirus pinchaque) in Colombia
Authors: Lizcano D. J. , Pizarro V. , Cavelier J. , Carmona J.
Published: March 2003

Aim

We conducted a study to estimate the past and present distribution and population size of T. pinchaque in Colombia.

Location

The study included all mountain ranges above 2000 m.

Methods

The past distribution was obtained by plotting on a map of past distribution of montane rain forests, the geographical locations with the name `danta' or `tapir' above 2000 m obtained from topographic maps, the locations cited in bibliographic references, and the results of interviews in the 530 Andean municipalities. The present distribution was obtained by plotting the present distribution of montane rain forests, the results of interviews and ground control. Population size was estimated by combining measurements of population density with maps of present distribution.

Results

In the past, the species occurred in the central and eastern Cordilleras, as well as in the Andean Massive where the three cordilleras merge in the south of the country. Currently, the species occurs in the central Andes south of Nevados National Park, and in the eastern Andes, south of Paramo de Sumapaz, Bogotá. According to our most optimistic estimates, there are about 2500 tapirs in the Andes of Colombia.

Main conclusions

These individuals occur in a total of thirty‐five forest patches that range from 5 to 3700 km2. Only five to six fragments have the minimum necessary size (826 km2) to maintain at least 150 individuals, the estimated number to maintain viable population in the short term. The populations most threatened are those of the central Cordillera between P.N. Las Hermosas and P.N. Nevado del Huila where large tracts of mature montane forests are being converted to opium fields.