bluuebunny/crossref_metadata_2025_split huggingface dataset:
What limits the distributions of coastally restricted terrestrial invertebrates? The case of coastal landhoppers (Crustacea: Amphipoda: Talitridae) in southern Tasmania
Authors: Richardson Alastair M. M. , Swain Roy , McCoull Colin 
Published: May 2003

AbstractAim  A number of terrestrial invertebrates are known to have distributions limited to the immediate coastal zone, but the factors controlling their distributions are not well understood. This study was planned to correlate the distribution of a coastal terrestrial amphipod, Austrotroides maritimus Friend 1987, which is only found within 100 m of the high tide mark, with soil characteristics and salt deposition.Location  South Cape Rivulet Bay on the south coast of Tasmania (146°47′ E, 43°36′ S).Methods  Abundance of the amphipods was examined at four sites c. 200 m apart that varied in their exposure to onshore westerly winds. At each site four replicate transect lines were established 3 m apart, with pitfall traps set at 2‐m intervals. The lines were at right angles to the high water mark and extended beyond the inland limit of A. maritimus. Amphipods were trapped at three times of the year, in winter, spring and summer (1993–94), and the sodium content, organic content and moisture content of the soil at each trap site were measured. The sodium content of rain falling on the transects, was also measured, and lysimeters were used to assess the concentration of sodium in water penetrating the soil profile.Results  The inland penetration of A. maritimus varied between 18 and 44 m from the seaward edge of woody terrestrial vegetation (itself <10 m horizontally from the high tide mark). Inland penetration increased from west to east around the bay, following an apparent gradient of increased exposure to onshore winds. At the most easterly and apparently most exposed site, however, the species penetrated only 18 m, but this site differed markedly from the others in its topography, caused by erosion of the dunes, with an 8‐m cliff at its seaward end. The soils at this site were also unusually clayey and waterlogged. Amphipod abundance did not correlate strongly with any of the soil parameters. The salt content of rainfall generally declined inland, as did the concentration of lysimeter leachate, but the inland declines were not all smooth, and both rainfall and lysimeter leachate concentration showed some tendency to increase inland at the most sheltered site.Main conclusions  Austrotroides maritimus is strongly restricted to the immediate coastal zone. The extent of its inland penetration correlates with exposure to onshore winds, and circumstantial evidence supports the hypothesis that this may be due to differences in the amount of salts deposited.
Hawaiian biogeography and the islands’ freshwater fish fauna
Authors: McDowall R. M. 
Published: May 2003

AbstractAim  This paper describes known patterns in the distributions and relationships of Hawaiian freshwater fishes, and compares these patterns with those exhibited by Hawaii's terrestrial biota.Location  The study is based in Hawaii, and seeks patterns across the tropical and subtropical Indo‐west Pacific.Methods  The study is based primarily on literature analysis.Results  The Hawaiian freshwater fish fauna comprises five species of goby in five different genera (Gobiidae). Four species are Hawaiian endemics, the fifth shared with islands in the western tropical Pacific Ocean. All genera are represented widely across the Indo‐west Pacific. All five species are present on all of the major Hawaiian islands. All five species are amphidromous – their larval and early juvenile life being spent in the sea. Although there has been some local phyletic evolution to produce Hawaiian endemics, there has been no local radiation to produce single‐island endemics across the archipelago. Nor is there evidence for genetic structuring among populations in the various islands.Main conclusions  In this regard, the freshwater fish fauna of Hawaii differs from the well‐known patterns of local evolution and radiation in Hawaiian Island terrestrial taxa. Amphidromy probably explains the biogeographical idiosyncrasies of the fish fauna – dispersal through the sea initially brought the fish species to Hawaii, and gene flow among populations, across the archipelago, has hitherto inhibited the evolution of local island endemics, apparently even retarding genetic structuring on individual islands.
The relationship between British ground beetles (Coleoptera, Carabidae) and land cover
Authors: Eyre M. D. , Luff M. L. , Staley J. R. , Telfer M. G. 
Published: May 2003

AbstractAims and methodsGround beetle and satellite‐derived land cover data from 1687 United Kingdom 10 km national grid squares were used to assess the relationship between species pool and cover data in Great Britain using fuzzy classification and constrained ordination.ResultsGround beetle species pools classified into nine groups which were related to land cover variables using constrained ordination. There was a strong relationship between upland land cover and three ground beetle groups. Deciduous woodland, coastal and tilled land were associated with three other groups. Three further groups did not appear to be strongly associated with any particular cover, but differed in geographical position.ConclusionThe distribution of species pools derived from the British national recording scheme at the 10 km scale was strongly related to satellite‐derived land cover data. There appears to be considerable potential for the use of a synthesis of land cover and ground beetle data in the monitoring of environmental change over a large, countrywide, area.
Influence of climate on Bonelli's eagle's (Hieraaetus fasciatus V. 1822) breeding success through the Western Mediterranean
Authors: Ontiveros Diego , Pleguezuelos Juan M. 
Published: May 2003

AbstractAim  To assess the impact of certain climatic variables on the breeding success of some populations of Bonelli's eagle (Hieraaetus fasciatus V. 1822) throughout its latitudinal distribution range, in order to account for recent and differential declines in populations.Location  Western Mediterranean, from southern Morocco to southern France.Methods  Seven populations were considered for the latitudinal distribution range of the species. Data from 1052 breeding attempts were taken from the literature and, for each population, breeding success was measured as the mean number of fledglings per pair per year. Breeding success, as a dependent variable, was related to five geographical and climatic variables (latitude, mean annual temperature, mean minimum temperature of the coldest month, mean maximum temperature of the hottest month and mean annual precipitation) as independent variables, through some regression models, which take into account the multicolinearity of the variables.Results  All the analyses agreed that average annual temperature was an important factor associated with the breeding success of the species in each region, and accounted for up to 97% of the variance of the breeding success throughout a latitudinal gradient in the study area.Main conclusions  The low breeding success of the northern populations (probably because of climatic constraints) and the tendency of juveniles to disperse southwards, diminishes recruitment in those populations. Therefore, as human pressure and habitat destruction causes high adult and pre‐adult mortality of the species throughout its entire latitudinal range, disturbances in the northern populations have more profound effects, thereby explaining observed population declines.
Regional differences in responses of chinook salmon populations to large‐scale climatic patterns
Authors: Levin Phillip S. 
Published: May 2003

AbstractAim  To quantitatively explore the extent to which many different populations of the same species (chinook salmon, Oncorhynchus tshawytscha) respond cohesively to a common large‐scale climatic trend.Location  The Columbia River basin of the northwestern US.Methods  I used regression analyses to describe the downward trend in population growth (number of recruits per spawning adult) for thirteen populations of chinook salmon distributed among three geographical regions: Snake River, Upper Columbia River and Middle Columbia River. I then used residuals from these regressions to characterize per capita productivity for each brood year. Positive residuals indicated productivity higher than that predicted by the time series, while negative residuals revealed years in which productivity was lower than predicted. I next used analysis of covariance (ancova) to test the null hypothesis that associations between ocean/climate conditions and deviations from predicted population growth did not vary among geographical regions. All ancovas used residuals generated from the regressions as the response variable, geographical region as the main effect, and climatic condition [characterized by the Pacific Decadal Oscillation index (PDO)] as the covariate. A major climate shift occurred in 1977, and because the association of the PDO with salmon productivity varied between the pre‐ and post‐1977 climate regimes, I analysed data from the two regimes separately.Results  There were marked impacts of climate on salmon production that varied among geographical regions and between decade‐scale climate regimes. During the pre‐1977 climate regime, productivity of salmon populations from the Snake River tended to exceed expectations (i.e. residuals were positive) when values of the PDO were negative. In contrast, this pattern was not evident in populations from the upper or middle Columbia Rivers. During the post‐1977 regime when ocean productivity was generally lower, the association of the PDO with salmon productivity changed – productivity tended to fall short of expectations (i.e. residuals were negative) when values of the PDO were negative.Main conclusions  Understanding the linkages between salmon populations and climate is critical as managers attempt to preserve threatened salmon populations in the face of both natural or human‐induced climate variation and the litany of human activities affecting salmon. An important step in this understanding is the recognition that the response to ocean/climate change by salmon populations of the same species and river basin is not necessarily homogeneous.
The Middle Asian Element in the Southern Rocky Mountain Flora of the western United States: a critical biogeographical review
Authors: Weber William A. 
Published: May 2003

AbstractAim Presentation of an hypothesis suggesting that the extraordinarily similarity of the Russian Altai and the American Southern Rocky Mountain Flora represents an Oroboreal Flora; that had to have had an essential continuity across the northern part of the world in the Tertiary period, constituting a highland and steppe component of the better‐known Arcto‐Tertiary Flora of eastern and far‐western North America and eastern Asia.Location North America and Middle (Altai) Asia.Methods Summarization of the author's field and herbarium studies of whole floras over a period of over 60 years, consisting of successive specializations in vascular plants, lichens, and bryophytes.Main conclusions (1) The modern alpine and associated marginal steppe and montane floras contain taxa of Tertiary age. (2) The floras of the southern mountains antedate those of the present‐day Arctic. (3) The Middle Asiatic and the North American floras once enjoyed a contiguous existence over a broad area involving connections between North America and Asia across the North Pole by way of Greenland. Their present disjunctions are products of extinction and attrition of ranges, not of long‐distance migration or dispersal mechanisms. (4) North‐eastern North American disjunctions of so‐called Cordilleran species (the Nunatak hypothesis) need not require explanations involving long‐distance dispersal or migration, but represent relictual populations of the once widely distributed Oroboreal flora.
Trophic diversity of the otter (Lutra lutraL.) in temperate and Mediterranean freshwater habitats
Authors: Clavero Miguel , Prenda José , Delibes Miguel 
Published: May 2003

AbstractAimTo analyse the geographical patterns in the composition and diversity of otter's (Lutra lutraL.) diet and their relationship with climatic characteristics.LocationEuropean freshwater habitats under Mediterranean and temperate climatic regimes.MethodsThirty‐seven otter diet studies were reviewed, twenty‐one from temperate and sixteen from Mediterranean areas. All studies were based on spraint analysis and their results expressed as relative frequency of occurrence of seven main prey categories. Principal Component Analysis was performed to extract the main gradients of diet composition. Pearson's correlation andt‐tests were used to assess the relationship between diet characteristics (composition, diversity and taxonomic richness) and geographical and climatic variables.ResultsA clear latitudinal gradient in diet composition was observed. Otter diet was more diverse and featured more prey classes in southern localities, while the species was more piscivorous towards the north, where it predated upon a higher number of fish families. This pattern was similar when temperate and Mediterranean localities of Europe were compared. Mediterranean otters behaved as more generalist predators than temperate ones, relying less on fish, and more on aquatic invertebrates and reptiles.Main conclusionsGeographical differences in otter feeding ecology in Europe seem to be related with the two contrasted climatic conditions affecting prey populations. The otter can act as a highly specialized piscivorous predator in temperate freshwater ecosystems, which do not suffer a dry season and have a comparatively stable water regime compared to Mediterranean ones. However, the unpredictable prey availability in Mediterranean areas, affected by strong spatial and temporal water shortages, favours a diversification of the otter's diet.
Understanding Late Quaternary extinctions: the case of Myotragus balearicus (Bate, 1909)
Authors: Bover Pere , Antoni Alcover Josep 
Published: May 2003

AbstractAim  In this study we present a new view on the extinction of Myotragus balearicus, an extinct highly modified dwarf caprine from the Gymnesic Islands (or eastern Balearic Islands), as a methodological case study for interpretation of Late Quaternary extinctions (LQEs).Methods  We analyse all available 14C ages obtained from M. balearicus bones from the uppermost part of the Pleistocene and the Holocene, together with the available chronological data of the putative causes of Myotragus extinction.Results  It has been possible to define two critical dates that allow us to establish an ‘uncertainty period for the Myotragus extinction’ (UPME) in each analysed island (Mallorca, Menorca and Cabrera). For Mallorca, the UPME corresponds to the interval c. 3700 to 2030 calbc (i.e. c. 1670 years of uncertainty). In the case of Menorca, the UPME spans from 10,000 to 1930 calbc (8070 years of uncertainity). In Cabrera the UPME is placed between 3650 and 300 calbc (3350 years of uncertainty). These periods, together with a review of the available information on the chronology of human arrival and the chronology of Holocene climatic change, shed light on the possible causes of the extinction of this species.Main conclusions  Extinction of Myotragus because of climatic change can be definitively rejected. The Myotragus extinction must be attributed to the rapid effects of the first human occupation. The use of uncertainity periods for the disappearance of species represents a useful tool for the analysis of LQEs.
Phylogeography of the giant harlequin beetle (Acrocinus longimanus)
Authors: Zeh David W. , Zeh Jeanne A. , Bonilla Melvin M. 
Published: May 2003

AbstractAim The extent to which cryptic species contribute to neotropical diversity remains inadequately investigated. Based on its highly distinctive morphology, the giant harlequin beetle, Acrocinus longimanus, is currently described as a single species, ranging from southern Mexico to northern Argentina. However, the discovery of cryptic species in Cordylochernes scorpioides, a pseudoscorpion with obligate dependence on the harlequin beetle for dispersal, strongly suggests the existence of barriers to gene flow in A. longimanus. The aim of this study was therefore to determine whether levels of DNA divergence between geographical populations provided evidence of genetically distinct lineages in the harlequin beetle.Location Trinidad and Panamá.Methods Sequencing of 1245 bp of the mitochondrial cytochrome oxidase I (COI) gene of A. longimanus from seven locations in Trinidad and Panamá.Results Mitochondrial haplotype diversity in the harlequin beetle shows limited evidence of geographical structuring, with a maximum sequence divergence between populations of only 1.29%. This is an order of magnitude less than the level of COI divergence between harlequin beetle riding pseudoscorpions from the same geographical locations.Main conclusions The molecular data on populations from northern South America and Panamá are consistent with the current, morphologically based classification of A. longimanus as a single, pan‐neotropical species. In addition, the relatively low level of population divergence detected in this study indicates that speciation in the hitchhiking pseudoscorpion has occurred in the absence of significant barriers to gene flow in its beetle host. It is proposed that, in the harlequin beetle, the phylogenetic signal of colonization and vicariance associated with the formation of the Isthmus of Panamá has been obscured, although not fully erased, by historical and contemporary gene flow.
Variable photosynthetic acclimation in consecutive cohorts of Scots pine needles during 3 years of growth at elevated CO2 and elevated temperature
Authors: LUOMALA E.‐M. , LAITINEN K. , KELLOMÄKI S. , VAPAAVUORI E. 
Published: May 2003

ABSTRACTIn this experiment, the photosynthetic acclimation of successive needle cohorts of Scots pine were studied during 3 years of growth at elevated CO2 and temperature. Naturally regenerated Scots pine (Pinus sylvestris L.) trees were subjected to elevated CO2 concentration (+CO2, 700 p.p.m), elevated temperature (+T, ambient +2 to +6 °C) and to a combination of elevated CO2 and temperature (+CO2 + T) in closed‐top chambers, starting in August 1996. Trees growing in chambers with ambient CO2 and ambient temperature served as controls (AmbC). Elevated CO2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO2 was higher at +CO2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased. The interaction of +CO2 and +T on Rubisco was mostly negative; consequently, in the second and third year of the experiment the carboxylation capacity decreased at +CO2 + T. In the 1996, 1997 and 1998 cohorts, the structural N concentration of needles was lower at +CO2 than at AmbC. Elevated CO2 and elevated temperature generally had a positive interaction on N concentration; consequently, N concentration in needles decreased less at +CO2 + T than at +CO2. At +CO2 + T, the acclimation response of needles varied between years and was more pronounced in the 1‐year‐old needles of the 1997 cohort than in those of the 1998 cohort. Thus, acclimation was not always greater in 1‐year‐old needles than in current‐year needles. In the +CO2 + T treatment, elevated temperature had a greater effect on acclimation of needles than elevated CO2.
Calcium requirement for ethylene‐dependent responses involving 1‐aminocyclopropane‐1‐carboxylic acid oxidase in radicle tissues of germinated pea seeds*
Authors: PETRUZZELLI L. , STURARO M. , MAINIERI D. , LEUBNER‐METZGER G. 
Published: May 2003

ABSTRACTThe Ca2+ requirements of ethylene‐dependent responses were investigated in germinating seeds of Pisum sativum L. using 1‐aminocyclopropane‐1‐carboxylic acid (ACC) oxidase (Ps‐ACO1), ACC synthase (Ps‐ACS2) and class I β‐1,3‐glucanase as molecular markers. Ethylene biosynthesis and responsiveness are localized to the elongation and differentiation zones of the pea radicle. Ethylene treatment induced ectopic root hair formation in the cell elongation zone and promoted root hair elongation growth in the radicles of germinated seeds. Characterized Ca2+ antagonists, including EGTA, lanthanum, verapamil, ruthenium red, W‐7, lithium and neomycin, were used to test for the involvement of the apoplastic and the intracellular Ca2+‐pool, the Ca2+/calmodulin complex and the phoshoinositide (PI) cycle in the ethylene responses. Ca2+ release from internal pools, but no appreciabe apoplastic Ca2+, is involved in the transcriptional induction by ethylene of Ps‐ACO1 and in ectopic root hair formation in the radicle elongation zone of germinated pea seeds. Furthermore, the Ca2+/calmodulin complex and the PI cycle seem to be involved in these ethylene responses. In contrast, both the intracellular and the apoplastic Ca2+‐pools are required for the negative and positive ethylene responses to the gene expression of PS‐ACS2 and class I β‐1,3‐glucanase, respectively; and, apoplastic Ca2+ also promotes root hair elongation growth. Tissues from adult plants and germinating seeds exhibit temporal and spatial differences in the signal/response coupling by Ca2+ of ethylene‐regulated processes.
Two tomato non‐symbiotic haemoglobin genes are differentially expressed in response to diverse changes in mineral nutrient status
Authors: WANG Y.‐H. , KOCHIAN L. V. , DOYLE J. J. , GARVIN D. F. 
Published: May 2003

ABSTRACTThe role of plant non‐symbiotic haemoglobins remains undefined, but recent findings suggest a possible role in plant nitrate nutrition. This study sought to characterize patterns of gene expression for two tomato (Lycopersicon esculentum L.) non‐symbiotic haemoglobin genes, and to examine how diverse changes in nutrient status influences the expression of these two genes. The deduced amino acid sequences of the genes examined, SOLly GLB1 and SOLly GLB2, are 55% identical. SOLly GLB1 mRNA is present in highest abundance in roots and older stems, whereas SOLly GLB2 mRNA abundance is highest in leaves, but detectable in other tissues including roots. The SOLly GLB1 mRNA levels increased rapidly in roots in response to each nutrient treatment examined in hydroponic culture, including the individual removal of phosphate, potassium and iron from the culture medium, as well as by the addition of nitrate. In contrast, the levels of SOLly GLB2 mRNA were not significantly altered in response to these same treatments. These results are the first report that non‐symbiotic haemoglobin gene expression can be influenced by a broad range of changes both in mineral macronutrient and micronutrient status, suggesting a previously unrecognized generic role for non‐symbiotic haemoglobins in processes associated with mineral nutrient nutrition.