bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diversity of dry forest epiphytes along a gradient of human disturbance in the tropical Andes
Authors: Werner Florian A. , Gradstein S. Robbert 
Published: February 2009

AbstractQuestion: Disturbance effects on dry forest epiphytes are poorly known. How are epiphytic assemblages affected by different degrees of human disturbance, and what are the driving forces?Location: An inter‐Andean dry forest landscape at 2300 m elevation in northern Ecuador.Methods: We sampled epiphytic bryophytes and vascular plants on 100 trees of Acacia macracantha in five habitats: closed‐canopy mixed and pure acacia forest (old secondary), forest edge, young semi‐closed secondary woodland, and isolated trees in grassland.Results: Total species richness in forest edge habitats and on isolated trees was significantly lower than in closed forest types. Species density of vascular epiphytes (species per tree) did not differ significantly between habitat types. Species density of bryophytes, in contrast, was significantly lower in edge habitat and on isolated trees than in closed forest. Forest edge showed greater impoverishment than semi‐closed woodland and similar floristic affinity to isolated trees and to closed forest types. Assemblages were significantly nested; habitat types with major disturbance held only subsets of the closed forest assemblages, indicating a gradual reduction in niche availability. Distance to forest had no effect on species density of epiphytes on isolated trees, but species density was closely correlated with crown closure, a measure of canopy integrity.Main conclusions: Microclimatic changes but not dispersal constraints were key determinants of epiphyte assemblages following disturbance. Epiphytic cryptogams are sensitive indicators of microclimate and human disturbance in montane dry forests. The substantial impoverishment of edge habitat underlines the need for fragmentation studies on epiphytes elsewhere in the Tropics.
Gradients within gradients: The mesoscale distribution patterns of palms in a central Amazonian forest
Authors: Costa Flávia R.C. , Guillaumet Jean‐Louis , Lima Albertina P. , Pereira Ocirio S. 
Published: February 2009

AbstractQuestions:What are the relative contributions of environmental factors and geographic distance to palm community structure at the mesoscale, and how do they depend on the length of the environmental gradient covered? How do soil and topography affect variation of the canopy and understory palm community structure at the mesoscale? How does fine‐scale variation within the broad edaphic/topographic classes affect palm community composition?Location:Reserva Ducke, terra‐firme forest, Manaus, Brazil.Methods:Palms were sampled in 72 plots 250 m × 4 m, systematically distributed over an area of 100 km2. Soil, topography and distance to watercourses were measured for all plots. The relationship between community structure axes, summarized by NMDS ordinations, and environmental predictors, was analysed with multivariate regressions. Matrix regressions were used to determine the proportions of variance explained by environmental and geographic predictors.Results:Floristic variation at the mesoscale was mostly related to environmental variation, and the proportion of variance explained depended on the amplitude of the environmental gradient. Soil was the main predictor of floristic change, but its effects differed between life forms, with the understory palm community structured within one of the edaphic/topographic classes, in association with distance to watercourses.Conclusions:Dispersal limitation does not explain palm composition at the mesoscale, and the amplitude of environmental gradients covered by the analysis can be as important as the scale of analysis, in determining the relative contributions of environmental and geographical components to community structure. Soil and topography can predict a large proportion of palm composition, but gradients differ in scale, with some environmental gradients being nested within others. Therefore, although all environmental gradients are nested within distance, they do not necessarily coincide.
Effects of different fidelity measures and contexts on the determination of diagnostic species
Authors: Willner Wolfgang , Tichý Lubomír , Chytrý Milan 
Published: February 2009

AbstractQuestion: How different are lists of diagnostic species of vegetation units, derived using various fidelity measures, in different contexts and with presence/absence versus cover data?Methods: Six different fidelity measures were calculated for vegetation units of two classified data sets covering contrasting types of Central European vegetation (beech forest and dwarf shrub vegetation). Both statistical and non‐statistical fidelity measures were used, and either species presence/absence or cover was considered. Each measure was calculated on four hierarchical levels and within two different contexts, either within the whole data set or within the next higher level of hierarchical classification. Average similarities of the diagnostic species lists derived from various combinations of fidelity measures and contexts were calculated and visualized using principal coordinate analysis (PCoA).Results: The correlations between fidelity values derived from non‐statistical and statistical measures were rather weak. Nevertheless, diagnostic species lists calculated for the same syntaxon by different measures usually had several species in common. Average similarity between pairs of fidelity measures or contexts (based on the Sørensen similarity index) ranged from 0.21 to 0.92. PCoA clustered individual combinations of fidelity measures and contexts mainly according to the context and the use of presence/absence versus cover data, rather than according to the fidelity measures.Conclusions: The strongest impact on the lists of diagnostic species was not the fidelity measure itself but the context of its application and the use of presence/absence or cover data. Despite the weak correlation between individual fidelity values, traditional (non‐statistical) and statistical measures produce quite similar lists of diagnostic species, provided that the context of the analysis is the same. Both approaches have their advantages and disadvantages, and the choice of the appropriate algorithm should depend on the focus of the study.
Forest history and the development of old‐growth characteristics in fragmented boreal forests
Authors: Jönsson Mari T. , Fraver Shawn , Jonsson Bengt Gunnar 
Published: February 2009

AbstractQuestions: Can small and isolated high‐conservation value forests (e.g. designated woodland key habitats) maintain old‐growth forest characteristics and functionality in fragmented landscapes? To what extent have past disturbances (natural and anthropogenic) influenced the development of old‐growth characteristics of these forests? How long does it take for selectively cut stands to attain conditions resembling old‐growth forests?Location: Southern boreal zone of central Sweden.Methods: We linked multiple lines of evidence from historical records, biological archives, and analyses of current forest structure to reconstruct the forest history of a boreal landscape, with special emphasis on six remaining core localities of high‐conservation value forest stands.Results: Our reconstructions revealed that several of these stands experienced wildfires up to the 1890s; all had been selectively harvested in the late 1800s; and all underwent substantial structural and compositional reorganization over the following 100‐150 years. This time interval was sufficient to recover considerable amounts of standing and downed dead wood (mean 60.3 m3 ha−1), a range of tree ages and sizes (mean basal area 32.6 m2 ha−1), and dominance of shade‐tolerant spruce. It was insufficient to obtain clearly uneven tree age structures and large (>45 cm diameter) living and dead trees. Thus, these forests contain some, but not all, important compositional and structural attributes of old‐growth forests, their abundance being dependent on the timing and magnitude of past natural and anthropogenic disturbances. Our landscape‐level analysis showed marked compositional and structural differences between the historical forest landscape and the present landscape, with the latter having a greater proportion of young forests, introduction of non‐native species, and lack of large trees and dead wood.Conclusions: The remnant high‐conservation value stands were not true representatives of the pre‐industrial forests, but represent the last vestige of forests that have regenerated naturally and maintained a continuous tree cover. These traits, coupled with their capacity for old‐growth recovery, make them valuable focal areas for conservation.
Post‐fire tree establishment patterns at the alpine treeline ecotone: Mount Rainier National Park, Washington, USA
Authors: Stueve Kirk M. , Cerney Dawna L. , Rochefort Regina M. , Kurth Laurie L. 
Published: February 2009

AbstractQuestions: Does tree establishment: (1) occur at a treeline depressed by fire, (2) cause the forest line to ascend upslope, and/or (3) alter landscape heterogeneity? (4) What abiotic and biotic local site conditions are most important in structuring establishment patterns? (5) Does the abiotic setting become more important with increasing upslope distance from the forest line?Location: Western slopes of Mount Rainier, USA.Methods: We performed classification analysis of 1970 satellite imagery and 2003 aerial photography to delineate establishment. Local site conditions were calculated from a LIDAR‐based DEM, ancillary climate data, and 1970 tree locations in a GIS. We used logistic regression on a spatially weighted landscape matrix to rank variables.Results: Considerable establishment after 1970 caused forest line elevation to increase over 150 m in specific locations. Landscape heterogeneity increased with distance from the 1970 forest line. At a broad spatial context, we found establishment was most common near existing trees (0‐50 m) and at low elevations (1250‐1350 m). Slope aspect (W, NW, N, NE, and E), slope angle (40‐60°), and other abiotic factors emerged as important predictors of establishment with increasing upslope distance from the forest line to restricted spatial extents.Conclusions: Favorable climatic conditions likely triggered widespread tree establishment. Readily available seed probably enhanced establishment rates near sexually mature trees, particularly in the less stressful environment at low elevations. The mass effect of nearly ubiquitous establishment in these areas may have obscured the importance of the abiotic setting to restricted spatial extents. Topographic variability apparently produced favorable sites that facilitated opportunistic establishment with increasing upslope distance from the forest line, thereby enabling additional trees to invade the alpine tundra.
Limited effects of above‐ and belowground insects on community structure and function in a species‐rich grassland
Authors: Coupe Malcolm D. , Stacey J.N. , Cahill James F. 
Published: February 2009

AbstractQuestion: Do above‐ and belowground insects differentially impact plant community structure and function in a diverse native grassland?Location: Rough fescue prairie in Alberta, Canada.Methods: Above‐ and belowground insects were suppressed with insecticides for 5 years using a randomised block design. During this experiment, a severe drought began in 2001 and ended in 2003. Aboveground plant growth was measured as cover and biomass from 2001 to 2005. Root demography was measured in 2002 using a minirhizotron. Mixed models and repeated measures ANOVA were used to determine treatment effects on a number of response variables. MRBP were used to test for treatment effects on community composition.Results: Five years of insect suppression had few significant effects on plant growth, species richness or community composition, and were limited primarily to the severe drought in 2002. During the drought, insect attack increased root mortality, reduced plant cover, and altered community composition. Following the drought, plant responses were unaffected by insecticide application for the remainder of the experiment.Conclusions: Five years of insect suppression had only minor effects on community structure and function in this diverse native grassland. There was no indication that these effects increased over time. The results are counter to studies conducted in productive old‐field communities that revealed large effects of insects on community structure. We suggest that the unique features of this system, such as high species evenness, abundance of generalist herbivores, and a lack of competition for light among plants, limited the potential for insects to greatly impact community‐level processes.
Above‐ and belowground biomass allocation in Tibetan grasslands
Authors: Yang Yuanhe , Fang Jingyun , Ji Chengjun , Han Wenxuan 
Published: February 2009

AbstractQuestion: Optimal partitioning and isometric allocation are two important hypotheses in plant biomass allocation. We tested these two hypotheses at the community level, using field observations from Tibetan grasslands.Location: Qinghai‐Tibetan Plateau, China.Methods: We investigated allocation between above‐ and belowground biomass in alpine grasslands and its relationship with environmental factors using data collected from 141 sites across the plateau during 2001‐2005. We used reduced major axis (RMA) regression and general linear models (GLM) to perform data analysis.Results: The median values of aboveground biomass (MA), belowground biomass (MB), and root:shoot (R:S) ratio in alpine grasslands were 59.7, 330.5 g m−2, and 5.8, respectively. About 90% of total root biomass occurred in the top 30 cm of soil, with a larger proportion in the alpine meadow than in the alpine steppe (96 versus 86%). As soil nitrogen and soil moisture increased, both MA and MB increased, but R:S ratio did not show a significant change. MA scaled as 0.92 the power of MB, with 95% confidence intervals of 0.82‐1.02. The slope of the isometric relationship between log MA and log MB did not differ significantly between alpine steppe and alpine meadow. The isometric relationship was also independent of soil nitrogen and soil moisture.Conclusions: Our results support the isometric allocation hypothesis for the MA versus MB relationship in Tibetan grasslands.
Evidence from water chemistry as a criterion of ombrotrophy in the mire complexes of Abernethy Forest, Scotland
Authors: Proctor Michael C.F. , McHaffie Heather S. , Legg Colin J. , Amphlett Andy 
Published: February 2009

AbstractQuestion: Can cation analyses of water samples within a peatland site be used to infer solute sources to the samples, and so provide an objective criterion of ombrotrophy?Location: Mire complexes within native Pinus sylvestris forest, in Abernethy Forest, north of the Cairngorm Mountains, Scotland, UK.Methods: Chemical analyses of major cations in 200 water samples, and χ2 analysis of contingency tables relating species occurrence in the corresponding quadrat samples to the ombrotrophic‐telluric division.Results and conclusions: The chemical data (especially the ratios Ca2+/Mg2+ and Na+/Mg2+) indicated a separation of about 140 essentially ombrotrophic samples from about 60 showing clear telluric influence; these conclusions are consistent with published rainwater analyses. For hydrological and meteorological reasons, a sharp separation cannot be expected, so the limit adopted here (Ca/Mg=1.0) is to some extent arbitrary, but the methods described provide a more objective criterion of ombrotrophy than any other. Contingency tables showed highly significant associations between species occurrence and the ombrotrophic‐telluric division. The strongest associations included: (ombrotrophic) Eriophorum vaginatum, Odontoschisma sphagni and Sphagnum cuspidatum; (telluric) Carex panicea, Potentilla erecta, Carex echinata, Narthecium ossifragum, Sphagnum auriculatum s.l., Agrostis canina, Molinia caerulea, Eriophorum angustifolium, and Sphagnum recurvum s.l. The Abernethy mires are arguably more comparable with mire complexes on base‐poor rocks in southern Scandinavia than with most ombrotrophic sites further south and west in Britain. As in Sweden, Narthecium ossifragum and Eriophorum angustifolium, generally ubiquitous on British and Irish ombrotrophic bogs, are “fen” plants at Abernethy.
Alpaca plant poisonings: nitrate–nitrite and possible cyanide
Authors: McKenzie RA , Gordon AN , Burren BG , Gibson JA , Gardner MP 
Published: February 2009

Nitrate–nitrite poisoning killed four adult alpacas and induced the abortion of a full‐term fetus after access to oaten hay (Avena sativa) containing 3.2% KNO3equivalent in dry matter. Necropsy findings were cyanosis, dark‐coloured blood, and pulmonary congestion and oedema. Aqueous humour from two adults contained 25 mg NO3/L and that from the fetus contained 10 mg NO3/L. Cyanide poisoning possibly killed two adult wether alpacas that ate a garden‐cultivated variety ofOsteospermum ecklonis(South African daisy, bietou) with a cyanide potential of 6800 mg HCN/kg dry matter.
Ultraweak and Induced Photon Emission After Wounding of Plants
Authors: Winkler R. , Guttenberger H. , Klima H. 
Published: February 2009

AbstractThe ultraweak and induced photon emission were measured by a single photon counting equipment (Photomultiplier Hamamatsu R562) on Cucurbita pepo variaca styriacae after wounding. Wounding significantly changes the emission from a stationary to a nonstationary state and the shape of the decay curve obtained after light illumination. The rise in the ultraweak photon emission depends on the kind of wounding and its localization on the plant. The decay curves obtained after wounding could be better fit by an exponential function than by a hyperbolic one. So the biophoton emission correlates with physiological and bioelectrical changes like membrane depolarizations as they also depend on the kind of injury.
A History ofTheoria
Authors: HANSSON SVEN OVE 
Published: February 2009

Abstract:Theoria, the international Swedish philosophy journal, was founded in 1935. Its contributors in the first 75 years include the major Swedish philosophers from this period and in addition a long list of international philosophers, including A. J. Ayer, C. D. Broad, Ernst Cassirer, Hector Neri Castañeda, Arthur C. Danto, Donald Davidson, Nelson Goodman, R. M. Hare, Carl G. Hempel, Jaakko Hintikka, Saul Kripke, Henry E. Kyburg, Keith Lehrer, Isaac Levi, David Lewis, Gerald MacCallum, Richard Montague, Otto Neurath, Arthur N. Prior, W. V. Quine, Nicholas Rescher, Ernest Sosa, Robert C. Stalnaker, P. F. Strawson, Patrick Suppes, Johan van Benthem, Georg Henrik von Wright and many others. Hempel's confirmation paradoxes, Ross's deontic paradox, Montague's universal grammar and Lindström's theorem are among the contributions to philosophy that were first published inTheoria.
Erythrocyte Pyruvate Kinase Deficiency in a Beagle Dog
Authors: Harvey John W. , Kaneko J. J. , Hudson Edward B. 
Published: February 2009

SUMMARYA macrocytic hypochromic anemia with marked reticulocytosis was observed at each of 10 examinations during a 4 month period of a male Beagle dog that was 11 months old when first examined. The owner had noticed pale mucous membranes from the time the dog was purchased at 7 weeks of age. Based on the clinical history and negative LE, ANA and Coombs tests, an intrinsic erythrocyte defect was suspected.Erythrocyte osmotic fragility and hemoglobin electrophoresis were normal. Autohemolysis of incubated erythrocytes was marked. Hemolysis was uncorrected by glucose but partially corrected by ATP. With the exception of pyruvate kinase (PK), all of the erythrocyte enzymes measured had greater activities than those of control Beagle erythrocytes. In comparison to moderately reticulocyte‐rich controls. PK activity was low in the affected Beagle. Erythrocyte phosphoenolpyruvate content was increased significantly as expected in PK deficiency. The kinetic constant (Km) for phosphoenolpyruvate was lower than that of normal control dogs, a finding in agreement with studies of PK from deficient Basenjis. On these bases a diagnosis of PK deficiency was made.
Determination of Serum Albumin in Domestic Animals Using the Immediate Bromcresol Green Reaction
Authors: Gentry P.A. , Lumsden J. H. 
Published: February 2009

SUMMARYThe immediate reaction bromcresol green (BCG) method for determination of serum albumin in various species of domestic animals (bovine, equine, canine, feline and porcine) was compared to an electrophoretic method. Good correlation was obtained between the two methods when both species specific and bovine albumin standards were used to compute the albumin concentration for the BCG assay. The immediate reaction BCG method appears to have considerable potential for application in the veterinary clinical laboratory.
Plasma Ammonia Concentration in Dogs Using Ion‐Exchange Method of Analysis
Authors: Zenoble Robert D. , Prasse Keith W. 
Published: February 2009

SUMMARYLaboratory methods for measuring plasma ammonia concentration were reviewed. The ion‐exchange method of analysis was evaluated using canine plasma from 15 clinically normal dogs and five dogs with portosystemic shunts. Mean and standard deviation was 40.3 ± 8.1 ug NH3/dl in normal dogs and values ranged from 125 to 200 ugNH3/dl in dogs with portosystemic shunts. Handling of blood samples properly for accurate results was found to require pre‐chilled collection tubes, chilling the sample in an ice bath, immediate separation of plasma from red blood cells and immediate analysis for ammonia concentration. The ion exchange method was determined to be sufficiently accurate for clinical use and is suggested for any veterinary clinical pathology laboratory.
Effects of I.M. Injections on Serum Creatine Phosphokinase (CPK) Values in Dogs
Authors: Lewis H. B. , Rhodes D. C. 
Published: February 2009

SUMMARYIntramuscular injections of compounds of low irritancy (bicillin, Valium, saline) were found to cause significant elevations in serum CPK in dogs. This route of treatment must therefore be avoided in clinical conditions where CPK values have daignostic or prognostic importance.
Hyperosmolemic Changes Following Experimental Ethylene Glycol Intoxication In Dogs
Authors: Green R.A. , Omer V.V. St. , Zumwalt R.W. , Dallman M.J. 
Published: February 2009

SUMMARYExperimental ethylene glycol toxicosis in dogs produced a marked increase in serum osmolality. By comparing measured and calculated serum osmolality and relating this difference to plasma ethylene glycol, it was determined that ethylene glycol was primarily responsible for the hyperosmolemia. Osmometry may provide a useful adjunct to other diagnostic tests in identifying ethylene glycol intoxicated dogs during the early, most treatable, stage of toxicosis.
A Comparison of Coulter ZBI and Fisher Autocytometer II Hematological Values in 28 Mammalian Species at the Metropolitan Toronto Zoo
Authors: Chan A. , Carnio J. , Rapley W.A. , Mehren K.G. 
Published: February 2009

SummaryOne hundred and thirty‐three blood samples from twenty‐eight mammalian, non‐domestic species were analyzed using both the Coulter ZBI and Fisher Autocytometer II. The WBC, RBC and Hb values for each species from both machines, were compared. The study indicated that for 27 species there was no significant difference (P>0.05) between machines for the WBC. Twenty‐one species showed no significant difference (P > 0.05) in the RBC results. Only one species exhibited a significant difference (P>0.05) between machines in the hemoglobin value obtained.
Activated Coagulation Times of Normal Cows
Authors: Riley J.H. , Lassen E.D. 
Published: February 2009

SummaryThe Activated Coagulation Time (ACT) was determined on 10 normal cows. Duplicate samples were taken from each cow. The mean ACT was 145 seconds with a range of 120–180 seconds. Standard deviations were 18 and 13 for the first and second sampling, respectively. Repeatability of the ACT was acceptable.