bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of temporal autocorrelation on apparent growth rate variation in forest tree census data and an alternative distribution function of tree growth rate
Authors: Kohyama Takashi , Kubo Takuya , Macklin Eric 
Published: December 2004

AbstractDistributions of forest tree growth rates often display wide variation and positive skewness even within a narrow range of tree sizes. Temporal autocorrelation of growth rates is also commonly observed in forest trees. We suggest that temporal autocorrelation causes the positive skew in growth rate distributions. We propose the ‘passage’ distribution of growth rates, defined by the density of trees passing a particular size over a given inter‐census interval, as a superior description of growth performance of trees with temporally autocorrelated growth. We relate the passage distribution to the conventional ‘resident’ distribution of growth rates, defined by the growth rates of trees within a particular size range at a given census. The passage distribution is approximated by the resident distribution weighted by the absolute growth rate. For common rain forest tree populations, the average of the passage distribution is nearly twice that of the resident distribution. Simulation models which use growth rates estimated from resident distributions and assume a Markov process are valid only to reconstruct the dynamics of the overall size structure of a stand. When examining the influence of life history strategy on forest dynamics, models must incorporate the effect of temporal autocorrelation on growth rates.
Bacterial biomass on fine detritus particles in a woodland stream of Hokkaido, Japan
Authors: Kamauchi Hiromitsu 
Published: December 2004

AbstractBacterial biomass on four different size fractions of benthic fine particulate organic matter (FPOM) was measured throughout a year in a woodland stream in Hokkaido, Japan. Bacterial biomass per ash free dry mass (AFDM) of the FPOM was significantly different among the four size fractions, while the biomass per unit surface area of FPOM was not. Annual mean of bacterial biomass per particle mass positively correlated to the surface area per mass in the four size fractions. In addition, negative correlation was found between the C:N ratio and bacterial biomass per AFDM in FPOM when all fractions were pooled. There was also negative correlation between C:N ratio and the surface area per particle mass in the four size fractions. The difference of bacterial biomass on FPOM among the size fractions could be ascribed to surface area and/or C:N ratio of FPOM, although these effects were not separately evaluated in the present study.
Edge effects in a tropical montane forest mosaic: experimental tests of post‐dispersal acorn removal
Authors: López‐Barrera Fabiola , Newton Adrian , Manson Robert 
Published: December 2004

AbstractForest edges created by scattered‐patch clear‐cutting have become common in tropical montane cloud forests in the highlands of Chiapas, Mexico. It was hypothesised that forest edges may influence regeneration of oak species, which are canopy dominants in these forests, by affecting the activities of small mammal species. Acorns of different oak species varying in germination timing were offered to predators and/or dispersers at different positions along replicated forest edges during 2 consecutive years. We investigated the effects of (1) edge type (hard and soft), (2) distance from the edge (0, 15, 30, 45 and 60 m inside forest fragments) and (3) oak species, on the rate of acorn removal mainly by small mammals. During a non‐masting year, acorn removal was affected by the interaction of edge type and distance from the edge (P<0.05), with acorn removal being highest near hard edges compared to adjacent forest interiors. As predicted, acorn removal was greater along soft (100%) than along hard edges (82%), but this pattern was recorded only during the non‐masting year. This study partly supports previous studies of rodents preferentially consuming acorns with early germination rather than acorns exhibiting dormancy, however these patterns may change with variation in acorn abundance. These results suggest that patch clear‐cutting affects regeneration processes within forest fragments by influencing the activities of small mammals, but the nature of this effect also depends on acorn abundance and the characteristics of the forest edge created.
Niche construction and polymorphism maintenance in metapopulations
Authors: Hui Cang , Yue Dongxia 
Published: December 2004

AbstractNiche construction, a term referring to the modification of their environments by any organism, can profoundly influence the genetic dynamics and structure of a metapopulation. Through niche construction, we give the dynamics and spatial structure of genotype frequencies using one‐ and two‐dimensional metapopulation lattice models, and these models generate archipelago‐like structures in space through an ecological imprint in order to maintain polymorphism with low genetic load within demes, which do not need heterozygote superiority. With habitat deterioration and restoration, niche construction generates a threshold phenomenon and obstructs the changes in environments. Hence, in practice, restoration is a more difficult process than deterioration. Furthermore, niche construction may serve as an important mechanism for maintaining diversity in nature, including genetic, species and ecosystem diversity.
Biomass and production of a naturally regenerated oak forest in southern Korea
Authors: Park In Hyeop , Son Yowhan , Kim Dong Yeob , Jin Hyun O , Yi Myong Jong , Kim Rae Hyun , Hwang Jung Ok 
Published: December 2004

AbstractBiomass and production of two stands with Quercus variabilis Bl. as the dominant species (stands 1 and 3) and one with Q. mongolica Fisch. as the dominant species (stand 2) were investigated in southern Korea. Stands 1 and 3 naturally occurred on sites with southerly aspects while stand 2 naturally occurred on northerly aspects; stand ages were similar for the three stands (36–38 years old). Total above‐ and belowground biomass including understory vegetation (Mg ha−1) was 108.4 for stand 1, 115.6 for stand 2, and 132.0 for stand 3, respectively. Understory vegetation constituted 17.4% of the total biomass in stand 1 but only 3.7–4.5% in stand 2 and stand 3. Roots constituted 20.1–24.6% of the biomass of the overstory vegetation. Although stand 3 showed the highest total biomass, net production was highest in stand 2 at 12.6 (Mg ha−1 year−1); net production levels for stands 1 and 3 were 11.7 and 11.1 (Mg ha−1 year−1), respectively. It appeared that the differences in site conditions related to aspect influenced the distribution of naturally regenerated oak species within a relatively small area and resulted in differences in biomass and production among the stands.
Foraging modes of stream benthic fishes in relation to their predation effects on local prey density
Authors: Inoue Mikio , Miyayoshi Masanobu , Sone Shin 
Published: December 2004

AbstractHabitat use and foraging behavior of two benthic insectivorous gobies, Rhinogobius sp. CO (cobalt type) and Rhinogobius sp. DA (dark type), were examined in relation to their predation effects on local prey density in a small coastal stream in southwestern Shikoku, Japan. Correlations among the foraging range, frequency of foraging attempts and current velocity indicated that individuals using fast‐current habitats had small foraging ranges and infrequently made foraging attempts while those in slow currents frequently foraged over large areas. The former and the latter were recognized as ambush and wandering foragers, respectively. Interspecific comparisons of habitat use, foraging behavior and prey preference suggested that Rhinogobius sp. CO selectively forage mobile prey by ambushing in fast currents, whereas Rhinogobius sp. DA randomly forage available prey by wandering in slow‐current habitats. A cage experiment was conducted to assess prey immigration rate and the degree of predation effects on local prey density in relation to current velocity. The results of the experiment support, at least in part, our initial predictions: (1) prey immigration rates increase with current velocity and (2) the effects of fish predation on local prey density are reduced as current velocity increases. Overall results illustrated a link between the foraging modes of the stream gobies and their predation effects on local prey density: fish adopt ambush foraging in fast currents, where the decrease in prey density tends to be less, whereas fish actively forage over large areas in slow currents, where the decrease in prey is relatively large.
Quaternary Paleoecology and Stratigraphy of the Sea Cliffs, Western Olympic Peninsula, Washington
Authors: Florer Linda E. 
Published: December 2004

The sea cliffs of the western Olympic Peninsula are composed chiefly of discontinuous beds of unconsolidated gravel, sand, silt, and peat of Pleistocene age. Two lower stratigraphic units, the “Steamboat Creek gravel” and “Joe Creek silt”, were deposited probably during the Puyallup Interglaciation; the upper unit, the “Kalaloch silt”, was deposited during an interval that extends from Salmon Springs Glaciation through Fraser Glaciation. Radiocarbon dates of the Kalaloch silt range from about 17,000 to &gt; 48,000 BP.
Pollen analysis and stratigraphic correlation of the sea cliff sediments indicate that the present vegetation of the Olympic Peninsula has existed in this part of western Washington since the Puyallup Interglacial. During the Puyallup, the low elevation Tsuga heterophylla-Picea forest or its seral stages were predominant. During subsequent glaciations the low elevation forest was replaced by montane or alpine plant communities in areas near the ice front. At sites farther removed from glacial termini, low elevation forest apparently persisted, thriving in centers from which constituent species spread during interstadials.
Stratigraphy and Origin of the Paha Topography of Northwestern Illinois
Authors: Flemal Ronald C. , Odom I. Edgar , Vail Ronald G. 
Published: December 2004

The paha of northwestern Illinois are longitudinal dunes developed in toto during Woodfordian time. Cores of noneolian materials, such as are typical in the paha of northeastern Iowa, are either not present or much reduced in numbers in the paha of Illinois. Variation in the thickness of the surface blanket of Peoria Loess accounts for the total topographic expression of the Illinois paha.
Underlying the Peoria Loess is a sequence of Pleistocene deposits consisting of two tills of Illinoian age, and the Plano Silt and Roxana Loess of Altonian age. Radiocarbon ages obtained from the Plano Silt range from 41,900 ± 1300 to 34,630 ± 710 radiocarbon years B.P.
Climatology of a Glacial Cycle
Authors: Fairbridge Rhodes W. 
Published: December 2004

A “glacial cycle” is defined as a major global climatic oscillation of the order of 105yr, developed within an “ice age”sensu latowhich may last 106–107yr and which recurs at widely spaced intervals in geologic time (ca. 2 × 108yr). The ice age situation thus only persists during 5–10% of all geologic time and is preconditioned by geotectonics andnotby extraterrestrial controls.The repetitive nature of the glacial cycle is demonstrated by independent records from (a) glacigenic, ice-melt deposits, i.e., tills and fluvioglacial terrace accumulations; (b) eolian by-products, i.e., loess; (c) marine terraces and beach deposits, eustasy inversely reflecting the ice volumes; and (d) deep-sea deposits, biologically and lithologically reflecting the climatic events. Only the marine section offers a continuous, uninterrupted record. Different chronometric techniques confirm a major cycle of the order of 105yr (eight repetitions in the last 700,000 yr), but there are multiple types of modulation, in part related to self-accelerating feedback, either negative (retardation) or positive, leading to acceleration.Within any given cycle there is an Interglacial, Anaglacial, Pleniglacial and Kataglacial phase, characteristics of which are repeated on a small scale in minor cycles. Their timing is variable in a latitudinal sense, apparently steered by radiation changes that first affect the tropics.Interglacials are defined in their classical stratotype areas of NW Europe, by sedimentary sequences characterized by the pollen of deciduous forests, pointing to climates at least as warm as those of the present time. The present cycle began ca. 10,000 YBP, with the start of the Holocene epoch, and the contemporary warm phase is seen as a typical interglacial stage. Such warm peaks characteristically last about 10,000 yr. Symptoms of the expected ensuing glaciation range from a global fall in temperature since mid Holocene, to tropical desiccation (growth of deserts) and high latitude retreat of tree lines.
Climatic Record in North Atlantic Deep-Sea Core V23-82: Comparison of the Last and Present Interglacials Based on Quantitative Time Series
Authors: Sancetta Constance , Imbrie John , Kipp N.G. , McIntyre Andrew , Ruddiman W.F. 
Published: December 2004

In North Atlantic deep-sea core V23-82, changing surface water conditions are revealed by changing composition of fauna and flora. Sedimentation rate seems to vary little so that approximate dating of climatic events within the X zone of Ericson is possible. These include an interglacial temperature maximum at 124,000 YBP; start of the post-Eemian cooling at about 116,000 YBP; and peak cool conditions at about 110,000 YBP, followed by warming.Drop in summer and winter temperatures about two-thirds of the way towards full glacial values and a significant drop of salinity is suggested by quantitative paleoenvironmental analysis of the 110,000 YBP cold episode.If the Eemian is taken as the analog of the present interglacial, a point in time 116,000 YBP becomes the historical model for today's ocean, and the North Atlantic is now approaching a time of severe cooling.
Abrupt Climatic Change at 90,000 yr BP: Faunal Evidence from Gulf of Mexico Cores
Authors: Kennett James P. , Huddlestun Paul 
Published: December 2004

Planktonic foraminiferal studies have been carried out on 28 piston cores of late Pleistocene age from the western Gulf of Mexico, an area of high sedimentation rates. For the interval between 73 × 103 and 95 × 103 yr BP, two of these cores have sedimentation rates of 12 and 15 cm/1000 yr. Calculation of the speed of faunal changes within this interval reveals an extremely rapid paleoclimatic-paleooceanographic change at approximately 90 × 103 years BP. Several species including distinctly warm-sensitive forms, then disappeared from the Gulf of Mexico in less than 350 yr, leaving a depleted planktonic foraminiferal fauna greatly dominated by only three species with little apparent temperature preference. This fauna existed for 2.5 × 103 yr after which distinctly cooler water elements increased in abundance rapidly and formed a high frequency peak approx 83.5–85 × 103 years BP. This increase in cooler water elements reflects either a return to more stable environmental conditions or a lag in their migration to the Gulf of Mexico after the severe climatic cooling, rather than further cooling.The faunal event in the Gulf of Mexico correlates with an even more spectacular event recorded in the Greenland ice sheet by a drop in 18O values within a time interval of only about 100 yr (Dansgaard et al., 1971, 1972). A possibly correlative climatic event of similarly rapid nature has also been reported for speleothems from southern France (Duplessy et al., 1970).The paleoclimatic event is closely associated stratigraphically with a widespread volcanic ash layer, although it is possibly significant that the increased volcanism occurred 1000 yr after the paleoclimatic event. A rapid lowering of the lysocline occurs simultaneously with the paleoclimatic event although faunal diversity is low in the succeeding fauna despite decreased calcium carbonate solution. Both the association with volcanism and changes in the position of the lysocline may be significant in consideration of mechanisms of such rapid climatic changes. In turn, such rapid paleoclimatic-paleooceanographic changes as observed in tropical Gulf of Mexico cores, in the Greenland ice sheet and in caves of southern France must be considered in the evaluation of causal mechanisms of glacial and interglacial oscillations.
Stratigraphic and Paleoclimatic Analysis of Late Pleistocene Tropical Southeast Pacific Cores (with an Appendix by N. J. Shackleton)
Authors: Luz Boaz 
Published: December 2004

AbstractFactor analysis of dissolution-resistant species of planktonic foraminifera in the >250 μm fraction of seabed and core samples from the tropical southeast Pacific yields five mappable varimax assemblages. The distribution of these assemblages in core tops is more related to the subsurface thermal structure than to the surface temperature. A transfer function relating the assemblages in core tops to the temperature at 200 m is applied to five cores. Cycles of estimated temperature in three cores are approximately in phase with climatic cycles in Atlantic cores spanning the past 200,000 yr, and display amplitudes on the order of 5°C. Two zones of increased calcium carbonate dissolution occur in these three cores. These zones occur in the transition from interglacial to glacial intervals. Temperature variations inferred are ascribed to fluctuations of the main thermocline, and the inference is made that during cold intervals the thermocline was displaced upward as the central water mass was areally diminished. A model of circulation dynamics suggests that such areal diminution would be associated with an intensified circulation. No significant fluctuations in the estimated 200 m temperature are inferred for a core in the Galápagos area during the last glacial, but a pronounced peak of high-latitude species Globorotalia inflata does occur. This peak is judged to reflect the removal of a low-oxygen ecological barrier.
North Pacific Radiolarian Assemblages and their Relationship to Oceanographic Parameters
Authors: Sachs Harvey Maurice 
Published: December 2004

AbstractA quantitative study of the distribution of Radiolaria in surface sediments of the North Pacific has demonstrated the feasibility of utilizing complete radiolarian thanatocoenoses as indicators of past oceanographic conditions.In samples from 36 core tops from the region 33° N-54° N, 148° E-140° W, 87–96% of all radiolarians encountered could be assigned to one of 120 taxa recognized. Q-mode factor analysis of distributional data for the 57 most abundant species yields four independent assemblages. Three of these reflect near-surface oceanographic conditions, and the fourth responds to bottom conditions. Regression-developed transfer functions describe the relationship between the assemblages and oceanographic parameters.
Climatic Record of the Past 130,000 Years in North Atlantic Deep-Sea Core V23-82: Correlation with the Terrestrial Record
Authors: Sancetta Constance , Imbrie John , Kipp N.G. 
Published: December 2004

AbstractQuantitative paleo-environmental analyses of planktonic foraminifera in 182 samples covering the past 130,000 years in North Atlantic deep-sea core V23-82 yield time series interpreted in terms of changing surface-water conditions. An absolute chronology is estimated by linear interpolation between levels dated by 14C or by stratigraphic correlation with other radiometrically dated climatic records. Significant events include: (1) rapid warming at 127,000 YBP, marking the start of the penultimate North Atlantic and European interglacial; (2) 124,000 YBP temperature maximum (Eemian); (3) 109,000 YBP cooling, correlated with the beginning of the last European glaciation (Würm), and representing a temporary cooling of the North Atlantic; (4) severe cooling 73,000 YBP, marking the start of the last full glacial regime in the North Atlantic; (5) short warm intervals within the last glacial regime dated at 59,000 YBP, 48,000 YBP, and 31,000 YBP; (6) rapid termination of the last glacial interval at 11,000 YBP; (7) a 6000 YBP hypsi-saline, followed by lowering salinity values presumably associated with decreasing flux of Gulf Stream waters over the core site.
Relative Elevation of Late Pleistocene High Sea Level Stands: Barbados Uplift Rates and their Implications
Authors: Matthews R.K. 
Published: December 2004

AbstractCalculations confirm that the uplift of Barbados during the past 130,000 yr has been at nearly constant relative rates in the Clermont and Christ Church standard traverses, and that sea levels responsible for Barbados terraces I (82,000 yr B.P.) and II (105,000 yr B.P.) attained approximately the same level which was 20–25 m below the level represented by Barbados III (125,000 yr B.P.).Preference for the correlation of Barbados III with the prominent first interglacial 18O peak in stage 5 is stated once again. Further, correlation with Eemian and Pangaion of the European pollen record is suggested.
Changes in the Poleward Energy Flux by the Atmosphere and Ocean as a Possible Cause for Ice Ages
Authors: Newell Reginald E. 
Published: December 2004

It is proposed that the two preferred modes of temperature and circulation of the atmosphere which occurred over the past 100,000 yr correspond to two modes of partitioning of the poleward energy flux between the atmosphere and ocean. At present the ocean carries an appreciable fraction of the transport, for example about three-eighths at 30°N. In the cold mode it is suggested that the ocean carries less, and the atmosphere more, than at present. During the formation of the ice, at 50,000 BP, for example, the overall flux is expected to be slightly lower than at present and during melting, at 16,000 BP, slightly higher. The transition between the modes is seen as a natural imbalance in the atmosphere-ocean energy budget with a gradual warming of the ocean during an Ice Age eventually cluminating in its termination. At the present the imbalance is thought to correspond to a natural cooling of the ocean, which will lead to the next Ice Age.The magnitude of temperature changes in the polar regions differ between the hemispheres in the same way as present seasonal changes, being larger in the northern than in the southern hemisphere.Overall the atmospheric energy cycle was more intense during the Ice Ages than now.Observational tests are proposed by which predictions from the present arguments may be compared with deductions about the environment of the past.Data used for the present state of the atmospheric general circulation are the latest global data available and contain no known major uncertainties. However, data for the oceanic circulation and energy budget are less well known for the present and almost unknown for the past. Hence the proposed imbalances must be treated as part of a speculative hypothesis, but one which eventually may be subject to observational test as no solar variability is invoked.