bluuebunny/crossref_metadata_2025 huggingface dataset:
An Evaluation of Techniques Used to Index Recruitment Variation and Year-Class Strength
Authors: Quist Michael C.
Published: February 2007

Recruitment is one of the most important factors influencing fish population dynamics, and although long-term data are probably the best source of information for explaining recruitment dynamics, such data are often unavailable due to logistic or monetary constraints. Consequently, a number of indices have been developed to index recruitment variability and year-class strength from a single sample. The purpose of this study was to compare two indices, the recruitment variability index (RVI) and recruitment coefficient of determination (RCD), with empirical estimates of walleye Sander vitreus recruitment variability in eight Kansas reservoirs. In addition, Studentized residuals from catch curves were compared with empirical estimates of year-class strength. Empirical estimates of recruitment variability were not related to RCD or RVI values from a single sample, and Studentized residuals from catch curves did not adequately index walleye recruitment for any of the study populations. Sampling bias was probably not the cause for the observed patterns, but examination of age-specific mortality rates indicated that mortality differed among ages (e.g., the mortality of age-2 fish was less than that of age-3 and older fish) and that mortality of a given age differed through time (i.e., the mortality of age-3 fish varied among years). These results suggest that angler behavior, in response to strong and weak year-classes, may affect the ability of indices to adequately assess recruitment dynamics. Mean RVI values estimated from multiple years of age structure data were significantly correlated with empirical estimates of walleye recruitment variability, suggesting that the RVI may be useful for indexing recruitment when data are available for more than 1 year. Although the indices examined in this study provide adequate assessments of recruitment dynamics for many fish populations, these results illustrate the importance of differential mortality among age-groups on index values and suggest that some form of index validation is necessary prior to their use.
Beginning to Write With Word Processing: Integrating Writing Process and Technology in a Primary Classroom
Authors: Van Leeuwen Charlene A. , Gabriel Martha A.
Published: February 2007

Writing behaviors of grade 1 children were explored as they used word processors to support their writing. Information was gathered in the form of field notes and audiotape transcripts from classroom observation sessions, along with informal interviews with students and teachers. Themes which emerged from the data analysis suggested a combination of influences at work in the classroom environment. These included (a) changes in the classroom culture with regard to tolerance of student talk during writing sessions; (b) the length and characteristics of student–teacher interactions; and (c) teacher instructional practices about writing with and without a word processor. Different aspects of the physical environment where the students wrote—classroom or computer lab—were found to have the potential to influence students' writing behavior and possibly the written work produced. Student writing behavior using word processors and pencil‐and‐paper revealed differences in reading and rereading of the work in progress. In view of these findings, considerations for classroom practice, including (a) developing realistic expectations, (b) adjusting instruction, (c) scheduling feedback, (d) adjusting minilesson timing, and (e) teaching students collaborative work skills are shared.
Poetry in Third Grade: Getting Started
Authors: Sekeres Diane Carver , Gregg Madeleine
Published: February 2007

Poetry should be an integral part of children's learning in elementary school. This article explains the classroom structures and routines through which third‐grade students in an inner‐city school became familiar with poetic language and learned to appreciate the artistry of poetry. Most of the students were struggling readers. Reading poetry challenged them in terms of attending to the reading process, understanding concepts presented in the poems, and learning to read aloud so that listeners could also make meaning of the poem.

The article includes descriptions of lessons on elements of poetry and poetic language, making meaning of poetry, imagery, and symbolism. The authors conclude with considerations in choosing poems, including students' reading abilities, integration with other disciplines, and the poetry curriculum itself.
Immunohistochemical Evaluation of Ki‐67 Expression and Apoptosis in Cyclosporin A‐Induced Gingival Overgrowth
Authors: Buduneli Nurcan , Buduneli Eralp , Çınar Sema , Lappin David , Kinane Denis F.
Published: February 2007

Background: This study was planned to evaluate cell division rate and apoptosis by immunohistochemical and in situ hybridization techniques in cyclosporin A (CsA)‐induced gingival overgrowth tissue samples to determine whether these processes played a role in the pathogenesis of this condition.

Methods: Fourteen CsA‐induced overgrowth tissues from renal transplant recipients, 10 control tissues from patients with plaque‐induced gingivitis, and 14 control tissues from systemically and periodontally healthy subjects were evaluated. In patient groups, clinical periodontal recordings and tissue sampling were performed before initiation of any periodontal intervention. Numbers of Ki‐67–positive cells/field and apoptotic cells/field in formalin‐fixed/paraffin‐embedded tissue sections were determined. Data were evaluated by one‐way analysis of variance, post hoc Sidak test with modified Bonferroni correction, and Pearson correlation analysis. Three phenytoin‐ and five nifedipine‐induced overgrowth tissues were also processed in the same way, and findings in these tissue specimens were evaluated as case series.

Results: The number of keratinocytes was significantly greater in the CsA‐induced gingival overgrowth group than in the healthy control group (P <0.0‐). Cells labeled by in situ end labeling, namely the apoptotic cells, were significantly fewer in the CsA group than in the gingivitis and healthy control groups (P <0.01). Overall, statistically significant positive correlations were found between the numbers of Ki‐67–positive cells and probing depth and hyperplastic, bleeding, and plaque indices (P <0.01). Phenytoin and nifedipine samples exhibited obviously higher expression of Ki‐67–positive cells than the CsA, gingivitis, and healthy control groups.

Conclusion: Our findings suggest that decreased apoptosis may have a more prominent role than increased cell division in the pathogenesis of CsA‐induced gingival overgrowth.
Periodontal Disease Progression Among Young Subjects With No Preventive Dental Care: A 52‐Month Follow‐Up Study
Authors: Oliveira Costa Fernando , Cota Luís Otávio Miranda , Costa José Eustáquio , Pordeus Isabela Almeida
Published: February 2007

Background: The aim of the present study was to assess the incidence, severity, and extension of periodontal disease among young subjects.

Methods: Three hundred sixty subjects from a public school in Belo Horizonte, Brazil were examined. Forty‐four subjects with bone loss (BL) and/or clinical attachment loss (CAL) ≥4 mm, and no dental care during the following 52 months, were considered the reference sample and were recalled for a second examination. At both examinations, statistical analyses were performed for CAL and BL for subject, tooth, and site. Comparisons of CAL at subject, tooth, and site levels were performed with the Wilcoxon test for matched samples. Comparisons of BL at subject, tooth, and site levels were performed with the McNemar and Student t tests for dependent samples.

Results: Findings indicated an increase in the number of sites with CAL >4 mm from baseline to follow‐up. Sites that exhibited BL increased from 2.14% at baseline to 7.5% at follow‐up (P <0.001). The severity of periodontitis was characterized by increased CAL values at affected sites at both examinations (P <0.001) and an increase in BL over time (mean BL at 35 affected sites was 2.6 mm at baseline and 3.5 mm at follow‐up; P = 0.001). In addition, a 34% incidence of BL was verified.

Conclusions: The incidence, severity, and extension of CAL and BL were significant findings. They indicate the importance of early detection of the disease and the need for preventive health care programs geared toward young subjects.
Associations of Abdominal Fat With Perceived Racism and Passive Emotional Responses to Racism in African American Women
Authors: Vines Anissa I. , Baird Donna Day , Stevens June , Hertz-Picciotto Irva , Light Kathleen C. , McNeilly Maya
Published: February 2007

Objectives. An excess in abdominal fat may predispose African American women to chronic health conditions such as diabetes and cardiovascular disease. Because stress may increase body fat in the center-body region, we used the waist-to-hip ratio (WHR) to examine associations between excess abdominal fat and perceived racism (a chronic stressor) and daily stress. Passive emotional responses to perceived racism, hypothesized to have particularly adverse effects, were also examined.

Methods. We controlled for body mass index in multiple logistic regression models among 447 African American women who completed a telephone interview on perceived racism.

Results. Passive emotional responses were not related to WHR (odds ratio [OR]=1.4; 95% confidence interval [CI]=0.8, 2.4). High perceived racism was associated with a low WHR in this population (OR=0.4; 95% CI=0.3, 0.8). However, high daily stress was related to a high WHR (OR=2.7; 95% CI=1.1, 6.7).

Conclusions. Findings support an association between daily stress and WHR but do not support our hypothesis that passive emotional responses to perceived racism increase abdominal fat. Further study of the stress physiology of perceived racism in African American women is warranted.
Environmental Health Practice: Statistically Based Performance Measurement
Authors: Enander Richard T. , Gagnon Ronald N. , Hanumara R. Choudary , Park Eugene , Armstrong Thomas , Gute David M.
Published: February 2007

Objectives. State environmental and health protection agencies have traditionally relied on a facility-by-facility inspection-enforcement paradigm to achieve compliance with government regulations. We evaluated the effectiveness of a new approach that uses a self-certification random sampling design.

Methods. Comprehensive environmental and occupational health data from a 3-year statewide industry self-certification initiative were collected from representative automotive refinishing facilities located in Rhode Island. Statistical comparisons between baseline and postintervention data facilitated a quantitative evaluation of statewide performance.

Results. The analysis of field data collected from 82 randomly selected automotive refinishing facilities showed statistically significant improvements (P<.05, Fisher exact test) in 4 major performance categories: occupational health and safety, air pollution control, hazardous waste management, and wastewater discharge. Statistical significance was also shown when a modified Bonferroni adjustment for multiple comparisons was performed.

Conclusions. Our findings suggest that the new self-certification approach to environmental and worker protection is effective and can be used as an adjunct to further enhance state and federal enforcement programs.
Alciato and the Grammarians: The Law and the Humanities in theParergon iuris libri duodecim
Authors: Drysdall Denis L.
Published: February 2007

Alciato'sParergon iuris libri duodecimbelongs to the tradition of humanist notebooks which begins with Valla'sElegantiaeand finds its most important representative in Poliziano'sMiscellanea. It purports to provide explanations of difficulties found in theCorpus iuris civilisbased on Alciato's reading in non-legal texts. However, it is apparent that he is also seeking to demonstrate his competence in the emendation and explication of these literary and historical texts. The remarks he is led to make about "grammatici" and "rhetores" are revealing of his personal attitudes and symptomatic of the evolution of attitudes in the world of education.
Reverse Transmutations: Béroalde de Vervilles Parody of Paracelsus inLe Moyen de parvenir: An Alchemical Language of Skepticism in the French Baroque*
Authors: Giordano Michael J.
Published: February 2007

This essay analyzes the skeptical ideas of one of the most notorious works of the French Baroque,Le Moyen de parvenir. Its author, Béroalde de Verville, described his anti-novel as "une Satyre universelle," and one of his noteworthy accomplishments was to provide his troubled age with a relatively complete and innovative skeptical language based on both esoteric and exoteric alchemy. Conceiving of his text as a critical athanor, Béroalde conducts numerous experiments in transmutation that would turn Paracelsus' concepts into a kind ofprima materia. Out of this reversion to the primordial emerges a general critique of ideas and social institutions through such alchemical notions as prime and ultimate matter, quintessence, astrosophy, the arcanum, the Archeus, and the Cagastrum.
Variation in species composition and vegetation structure of succulent scrub on Tenerife in relation to environmental variation
Authors: Otto Rüdiger , Fernández‐Palacios José María , Krüsi Bertil O.
Published: February 2007

Abstract. On Tenerife, the occurrence of environmental gradients over short distances provides a unique opportunity to investigate the relationship between vegetation and environmental factors. In the semi‐arid coastal region of Tenerife, floristic composition, species richness and vegetation structure of perennial plants have been studied in 67 locations covering the existing precipitation gradient.

On the island as a whole, variation in species composition could be best explained by mean annual precipitation; at coastal sites, substrate age and soil characteristics also played a significant role. On the other hand, substrate chemistry and the type of eruptive material explained little of the floristic variation. Stand biomass was strongly correlated with mean annual precipitation and was, on the youngest lava flows studied, also affected by substrate age. The native stem succulent species made up the bulk of total biomass along the whole precipitation gradient. Disturbed and undisturbed sites differed significantly in stand biomass and cover. Species richness was correlated with precipitation and substrate age. Distribution of plant functional types was also related to the precipitation gradient. The relative abundance of hemicryptophytes and shrubs with non‐hairy leaves increased with increasing precipitation whereas the ratio of shrubs with hairy/non‐hairy leaves and succulent plants decreased. Some alien plants were quite frequent at disturbed sites but, on the whole, they contributed little to the species spectrum and to the stand biomass. Undisturbed sites remained almost free of introduced species not considering annuals.
Vegetation and ecological gradients in abandoned salt pans in western France
Authors: Bouzillé J.‐B. , Kernéis E. , Bonis A. , Touzard B.
Published: February 2007

Abstract.Salt marshes along the Atlantic coast of France have been converted into solar salt pans since the 7th century. Salt production declined strongly from the 18th century onward, leading to the abandonment of many of these salt pans. High soil salinity is a residue from the original salt production and varies among salt pans according to time since abandonment, the current flooding regime and the effect of drainage measures. The relationships between the plant communities and seven environmental variables were investigated by Detrended Correspondence Analyses (DCA). Duration of flooding, electric conductivity and sodium saturation were most strongly related to variation in vegetation. TheHeleo‐chareto‐Hippuridetum vulgarisand theCaricetum ripariaeoccur in lagoons with slightly saline soil that are flooded for the longest time period; theScirpetum maritimi compactioccurs in salt pans with saline soil flooded for a long period; theAlopecuro‐Juncetum gerardiioccurs on saline soil where flooding is of short duration whereas theCarici‐Lolietum perennisis never flooded and occurs on only slightly saline soil.

Soil salinity and duration of flooding provide a satisfactory explanation of the variation in species composition in abandoned salt pans but land‐use practices, especially grazing, have to be taken into account to fully understand their floristic composition.
The response ofPuccinellia maritimato burial: A key to understanding its role in salt‐marsh dynamics?
Authors: Langlois E. , Bonis A. , Bouzillé J.B.
Published: February 2007

Abstract.The plant and sediment dynamics in salt marshes are strongly interrelated, but few data are available to document their interaction.Puccinellia maritimais a perennial grass that occurs widely in salt marshes and this study examines its role in the stabilization or trapping of sediment in the pioneer zone and its response to burial, a characteristic phenomenon in accreting salt marshes.Puccinellianot only appears to limit erosion but also to significantly enhance accretion. The functional role of this species is largely dependent on the local disturbance regime. The response ofPuccinelliato burial was studied in a series of burial treatments. Growth performance ofPuccinelliawas stimulated by burial of 4 mm sediment and reduced by burial of 8 mm/month. Burial under 12 mm of sediment led to high mortality of up to 97%. Response was determined by the instantaneous thickness of sediment rather than by the total quantity. Morphological response to burial consisted mainly of stem elongation. Plants collected from accretion zones in the field also produced tillers with adventitious roots at successive soil layers. The range of burial tolerances found forPuccinelliafits well with its occurrence in locations with up to 8 mm sediment accretion per tidal cycle, a common situation in the salt marsh studied.
Nutrient requirements of ephemeral plant species from wet, mesotrophic soils
Authors: Brouwer Emiel; , Backx Hans , Roelofs Jan G.M.
Published: February 2007

Abstract. Nanocyperion plant communities occur on wet, more or less nutrient‐poor and sparsely vegetated soils in temperate climates and are characterized by tiny, very shortlived plant species. Most of these have become locally extinct. It is generally assumed that drainage and eutrophication were the most important reasons for this decrease. However, chemical analysis of soil pore water from plots on growth sites of these ephemerals showed that phosphorus availability was relatively high.

In a greenhouse experiment, the growth of ephemeral species was strongly limited by the amount of available phosphorus, whereas there was little or no limitation to the growth of other plant species from this habitat. At low phosphorus concentrations, the ephemeral species reached their reproductive phase within the same period, but showed a strong reduction in the amount of flowers that were produced. We concluded that ephemeral species in particular require a minimum amount of phosphorus for reproduction. Other species on nutrient‐poor, wet soils have a longer life span and can postpone flowering in nutrient‐poor soils.

In contrast to other short‐lived plant species from the same habitat, the growth of ephemeral species was barely stimulated by enhanced nitrogen availability. Apparently, the ephemerals are adapted to low nitrogen concentrations. The occurrence on nitrogen‐poor and relatively phosphorus‐rich soils suggests that this community may be very sensitive to nitrogen deposition. Reduced phosphorus availability below the minimum requirements of ephemerals, for example after acidification or the exclusion of human activities, has possibly contributed to the decrease of ephemeral plant species.
A simulation test of the resource‐averaging hypothesis of ecotone formation
Authors: Malanson George P. , Xiao Ningchuan , Alftine Kathryn J.
Published: February 2007

Abstract. The pattern at an ecotone may indicate the processes that created that ecotone. Such patterns may in turn affect the responses of ecotones to environmental change. The resource averaging hypothesis suggests a process for the development of tree lines that should produce patterns that are modifications of patterns in soil resources. A computer simulation model that embodies the resource averaging hypothesis is used to generate tree‐line patterns. Different spatial patterns in the variation of soil resources are represented in the model. The patterns of tree line computed by the simulation closely correspond to the patterns of soil resources that were input. These patterns are compared to patterns recorded in the field and by aerial photography. For the patterns of soil resources observed at some alpine tree lines, the model cannot produce the kinds of patterns of vegetation observed. Resource averaging alone cannot be an explanation of such tree lines.
Predictability of plant and fungal species richness of old‐growth boreal forest islands
Authors: Berglund Håkan , Jonsson Bengt Gunnar
Published: February 2007

Abstract.The fragmentation and deterioration of old‐growth forest habitat by modern forestry have become a major threat to species diversity in Fennoscandia. In order to develop a conservation strategy for the remaining diversity it is essential to identify the existing diversity and to develop appropriate conservation and monitoring programs. For these purposes indicators of conservation value for administrative prioritization are required. This study examines the predictability of plant and fungal species richness on two spatial scales on 46 isolated old‐growth forest islands (0.17 ‐ 12 ha) in a forest‐wetland mosaic. We explore (1) to what extent area, isolation and stand structure variables can explain the variation in species richness and (2) if richness patterns of individual species groups correlate. Isolation showed no relation to species richness. Area explained 50 ‐ 70% of the variation in total species richness and was positively related to the density of crustose lichens and Red‐list species in island interiors. Stand structure variables explained 28 ‐ 66% of the residual variation in total species richness after controlling for island size, and 15 ‐ 73% of the variation in density of species in island interiors. The highest predictability of species richness was found among substrate‐specific fungi and Red‐list species. Different stand structure variables were found to explain richness in the different species groups, and only among a few species groups species richness correlated. Thus, species richness of one single species group is unlikely to be a good indicator for total biodiversity. The results show that measurements of stand size and stand structure variables may be a strong complementary tool, and sometimes a substitute to extensive species inventories when one aims to estimate and monitor plant and fungal species diversity in old‐growthPicea abiesforests.
A new method for characterizing point patterns in plant ecology
Authors: Dale M.R.T. , Powell R.D.
Published: February 2007

Abstract.This paper describes new methods for the detection of the characteristics of spatial point patterns, based on counting plants in the circumcircles of triangles defined by triplets of the points themselves. In addition to counting points in the circumcircle, a further refinement is to count also the points in a ring around the circumcircle of the same area. This approach can be applied in a univariate form, with one species or one kind of plant, to detect and evaluate the best‐defined patches of plants and gaps. In the bivariate form, the method can be used to investigate the spatial characteristics of the relationship between different kinds of plants. These methods are illustrated by application to several data sets. In particular, the method is shown to be useful in describing the spatial relationship between seedlings and trees, both when the seedlings are on the forest floor beneath the canopy trees and when the seedlings represent post‐fire regeneration.
Tree mortality and effects of release from competition in an old‐growth Fagus‐Abies‐Picea stand
Authors: Szwagrzyk Jerzy , Szewczyk Janusz
Published: February 2007

Abstract. In a montane mixed Fagus‐Abies‐Picea forest in Babia Gora National Park (southern Poland), the dynamics of an old‐growth stand were studied by combining an 8‐yr annual census of trees in a 1‐ha permanent sample plot with radial increments of Abies and Picea growing in the central part of the plot. The mortality among the canopy trees was relatively high (10% in 8 yr), but the basal area increment of surviving trees slightly exceeded the losses caused by tree death. DBH increment was positively correlated with initial diameter in Abies and Picea, but not in Fagus. For individual trees smaller than the median height, basal area increment was positively related to the basal area of old snags and the basal area of recently deceased trees in their neighbourhood, but negatively related to the basal area of live trees. Dendrochronological analysis of the past growth patterns revealed numerous periods of release and suppression, which were usually not synchronized among the trees within a 0.3 ha plot. The almost normal distribution of canopy tree DBH and the small number of young individuals in the plot indicated that stand dynamics were synchronized over a relatively large area and, hence, were consistent with the developmental phase concept. On the other hand, the lack of synchronization among periods of growth acceleration in individual mature Abies and Picea trees conforms more closely to the gap‐dynamics paradigm.
Effects of age and distance on the composition of mixed deciduous forest fragments in an agricultural landscape
Authors: Jacquemyn Hans , Butaye Jan , Dumortier Myriam , Hermy Martin , Lust Noël
Published: February 2007

Abstract. Forest patches in central Belgium were inventoried twice for the presence or absence of forest plant species to study the effects of age and distance on species composition. All forests in the study area were subdivided based on their land use history. To avoid effects of autocorrelated environmental characteristics on species composition, habitat homogeneity was indirectly investigated using a TWINSPAN classification of the vegetation data. Two major habitats (alluvial and non‐alluvial forests) were distinguished and analysed separately. Patterns of species composition were investigated at the landscape level using Mantel tests. Species composition similarity measures were calculated between all pairs of fragments based on the floristic data. A highly significant correlation was found between species composition similarity and inter‐patch distance. Difference in age, which we used as a measure for habitat quality, was less important in explaining species composition patterns. The effects of spatial configuration became significant when difference in age was accounted for, and a partial correlation was calculated between inter‐patch distance and species composition similarity. Different results were found for alluvial and non‐alluvial forest types. Alluvial forests were more influenced by the spatial configuration than the non‐alluvial. For the non‐alluvial forest type effects measured with the difference in age between forest fragments obscured the effects of inter‐patch distance. Based on our findings we suggest that species composition is not only internally generated, but external processes such as differential colonization caused by varying degrees of isolation may be of overriding importance.
Scale‐dependent biases in species counts in a grassland
Authors: Klimeš Leoš , Dančak Martin , Hájek Michal , Jongepierová Ivana , Kučera Tomáš
Published: February 2007

Abstract. Numbers of plant species were recorded in species‐rich meadows in the Bílé Karpaty Mts., SE Czech Republic, with the aim to evaluate the sampling error made by well‐trained observers. Five observers recorded vascular plants in seven plots ranging from 9.8 cm2 to 4 m2 independently and were not time‐limited. In larger plots a discrepancy of 10–20% was found between individual estimates, in smaller plots discrepancy increased to 33%, on average. The gain in observed species richness by combining records of individual observers (in comparison with the mean numbers estimated by single observers) decreased from the smallest plot (27–82% for two to five observers) to the largest one (13–25%). However, after misidentified and suspicious records were eliminated, the gain was much lower and became scale‐independent; two observers added 12% species, on average, and the increase by combining species lists made by three or more observers was negligible (3% more on average). It is concluded that most discrepancies between individual observers were caused by misidentification of rare seedlings and young plants. We suggest that in species‐rich meadows plants should be recorded by at least three observers together and that they should consult all problematic plant specimens together in the field, to minimize errors.
Differential effects of reindeer on high Arctic lichens
Authors: van der Wal René , Brooker Rob , Cooper Elisabeth , Langvatn Rolf
Published: February 2007

Abstract. We studied the effects of Svalbard reindeer on the abundance of lichens in Spitsbergen. A survey was carried out in 14 areas with contrasting reindeer densities. Separate cover estimates for crustose, fructose and foliose lichens were taken in each area, and related to the density of reindeer pellet groups, a measure of reindeer density. Dominant macro lichen families were identified in 10 areas, and a full record of macrolichen species was taken in four additional areas. Variation in reindeer density is partially due to past overhunting, and subsequent incomplete recovery, releasing some areas from reindeer grazing for 100–200 yr.

The cover of fruticose lichens was negatively related to reindeer pellet group density, indicating suppression by Svalbard reindeer. This makes their impact comparable to other members of the Rangifer genus around the northern hemisphere. The generally recorded low abundance of lichens in the diet of Svalbard reindeer compared to other Rangifer species, therefore, was interpreted as the depletion of fruticose lichens in Spitsbergen, and a subsequent switch to alternative foods.

Of all fruticose lichens, Stereocaulon spp. appeared least sensitive to grazing. Crustose and foliose lichen cover was independent of reindeer pellet group density. The cover of crustose lichens was significantly related to latitude, with greater cover in more northern areas. Foliose lichens were more abundant in places where moss cover was high. We conclude that the impact of Svalbard reindeer on lichens is dependent on growth form, with fruticose lichens suffering from grazing, whereas foliose lichens might indirectly benefit from higher densities of reindeer or, like crustose lichens, be controlled by other factors.
Through‐growth by Pseudotsuga menziesii: A mechanism for change in forest composition without canopy gaps
Authors: Hunter John C. , Barbour Michael G.
Published: February 2007

Abstract. The currently prevailing view is that saplings require gaps or larger disturbances in order to grow into the canopy. This study documents an exception. In California's Pseudotsuga‐mixed hardwood forests, crowns of Pseudotsuga menziesii (Douglas fir) are within those of angiosperm trees (Arbutus menziesii and Quercus species). In the forests we examined, every Pseudotsuga was younger and all but one were growing more rapidly in girth than the Arbutus or Quercus whose crown it had penetrated. Furthermore, as saplings, the Pseudotsuga had grown at rates between those of suppressed saplings and canopy dominants. The recruitment of emergent Pseudotsuga substantially alters these canopies because of the large size Pseudotsuga attains. Given the density of Pseudotsuga growing in canopy crowns, such recruitment is likely. As a mechanism of recruitment, this through‐growth differs from gap recruitment in that the turnover of canopy trees is determined by an understory species' growth rate rather than the overstory species' longevity, and community attributes may change rapidly by replacement of canopy dominants with a dissimilar species. Pseudotsuga could grow through the canopy because of its greater potential height (> 60m vs. 20–40m for the angiosperms), narrower crown and its branches suffering less mechanical damage than those of the angiosperms. In general, resource levels in the understory, canopy height, and interspecific differences in maximum height and crown architecture all influence the likelihood of through‐growth. Therefore, for vegetation types whose dominants differ substantially in growth form, through‐growth may be a mechanism for rapid ecosystem change.
Diversity and succession of epiphytic macrolichen communities in low‐elevation managed conifer forests in Western Oregon
Authors: Peterson Eric B. , McCune B.
Published: February 2007

Abstract. We examined epiphytic macrolichen communities in Pseudotsuga menziesii (Douglas‐fir) forests across the western Oregon landscape for relationships to environmental gradients, stand age and structure, and commercial thinning. We used a retrospective, blocked design through the Coast and the western Cascade ranges of Oregon. Each of our 17 blocks consisted of a young, unthinned stand (age 50–110 yr); an adjacent, thinned stand of equivalent age; and an old‐growth stand (age > 200 yr). We found 110 epiphytic macrolichen taxa in the stands. Forage‐providing alectorioid lichens and the nitrogen‐fixing cyanolichen Lobaria oregana associated strongly with old‐growth stands and remnant old trees in younger stands (unthinned + thinned). Relative to unthinned stands, thinned stands had a slightly higher abundance of alectorioid lichens and a greater presence of Hypogymnia imshaugii. However, thinned stands hosted a lower landscape‐level (γ) diversity, lacking many species that occurred infrequently in the unthinned stands. Patterns in the lichen community composition correlated strongly with climatic gradients; the greatest variation in composition was between the Coast and Cascade ranges. The difference in communities between mountain ranges was greatest among stands 70–110 yr old, suggesting a difference in lichen successional dynamics between the ranges.
Spatio‐temporal colonization patterns of forest plant species in a mixed deciduous forest
Authors: Verheyen Kris , Hermy Martin
Published: February 2007

Abstract.An integrated analysis of the colonization patterns of forest plant species was carried out in a 34‐ha, mixed deciduous forest in northern Belgium. First, we sought to describe the relationships between land use history and environmental conditions. Land use history and soil type were related and negative correlations between pH and secondary forest age were found. The density of the shrub layer increases with secondary forest age. Litter quantity and cover ofUrtica dioicawere mainly indirectly influenced by land use history. Litter starts accumulating at low pH values and high shrub density andUrtica dioicagrows vigorously on nutrient enriched soils where much light can reach the ground. Next, the importance of these human‐altered environmental conditions for the colonization of forest plant species was assessed relative to the importance of dispersal limitation. Therefore, the distribution of 16 forest species was mapped and species‐specific spatio‐temporal isolation measures were calculated. The analysis revealed that the colonization patterns of the slowly colonizing species (i.e. ‘ancient forest plant species’) are best explained by a combination of spatio‐temporal isolation, soil type, pH and the (non‐)cover ofUrtica dioica.By contrast, spatio‐temporal isolation was never a limiting factor for good colonizing forest species. Our results suggest that colonization of ‘ancient forest plant species’ is hampered by a combination of dispersal‐ and recruitment limitation and that the relative importance of both factors is species‐specific.
Effects of nutrients and shade on tree‐grass interactions in an East African savanna
Authors: Ludwig Fulco , de Kroon Hans , Prins Herbert H.T. , Berendse Frank
Published: February 2007

Abstract. Savanna trees have a multitude of positive and negative effects on understorey grass production, but little is known about how these effects interact. We report on a fertilization and shading experiment carried out in a Tanzanian tropical dry savanna around Acacia tortilis trees. In two years of study there was no difference in grass production under tree canopies or in open grassland. Fertilization, however, indicate that trees do affect the nutrient limitation of the grass layer with an N‐limited system in open grassland to a P‐limited system under the trees. The N:P ratios of grass gave a reliable indication of the nature of nutrient limitation, but only when assessed at the end of the wet season. Mid‐wet season nutrient concentrations of grasses were higher under than outside the tree canopy, suggesting that factors other than nutrients limit grass production. A shading experiment indicated that light may be such a limiting factor during the wet season when water and nutrients are sufficiently available. However, in the dry season when water is scarce, the effect of shade on plant production became positive. We conclude that whether trees increase or decrease production of the herbaceous layer depends on how positive effects (increased soil fertility) and negative effects (shade and soil water availability) interact and that these interactions may significantly change between wet and dry seasons.
TURBOVEG, a comprehensive data base management system for vegetation data
Authors: Hennekens Stephan M. , Schaminée Joop H.J.
Published: February 2007

Abstract. The computer software package TURBOVEG (for Microsoft® Windows®) was developed in The Netherlands for the processing of phytosociological data. This package comprises an easy‐to‐use data base management system. The data bank to be managed can be divided into several data bases which may consist of up to 100 000 relevés each. The program provides methods for input, import, selection, and export of relevés. In 1994, TURBOVEG was accepted as the standard computer package for the European Vegetation Survey. Currently it has been installed in more than 25 countries throughout Europe and overseas.
Ceramic Standardization and Intensity of Production: Quantifying Degrees of Specialization
Authors: Roux Valentine
Published: February 2007

The aim of this study is to examine the relationship between metric variability of ceramic vessels of a single type and intensity of production. This relationship is examined on the basis of vessels made by Indian and Spanish potters whose rates of production vary from low to high. Results are compared with Filipino data to embrace different cultures and therefore possibly different emic conceptions of standardization. We conclude that rate of production affects the degree of standardization. However, only in a high-rate production situation do we have motor habits that transcend emic conceptions of standardization. Indeed, factors like size classes, emic conception of size classes, and skill may induce a certain variability despite similar rates of production. Indexing degrees of standardization needs, in other respects, to take into account the cumulative effect of production events that play on the CV (Coefficient of Variation) values. Applied to Mesopotamian data, our results suggest that third millennium ceramic production can be compared to low-rate production observed ethnographically.
The Local and the Distant in the Origin of Casas Grandes, Chihuahua, Mexico
Authors: Whalen Michael E. , Minnis Paul E.
Published: February 2007

Casas Grandes (or Paquimé), in northwestern Chihuahua, Mexico, is the largest and possibly the most complex community in the prehistoric Pueblo world. The literature is, and always has been, dominated by models that attribute the origin of this center to impulses coming from outside of the region. These arguments rest on the assumptions that the Casas Grandes area was underpopulated before the development of the center, and that there was little cultural continuity between Casas Grandes and its local predecessors. We use old and new data to argue against both of these ideas and in favor of in situ development of the center of Casas Grandes.
From Stewards to Bureaucrats: Architecture and Information Flow at Chan Chan, Peru
Authors: Topic John R.
Published: February 2007

Archaeologists working with complex societies are concerned with the administration of political economies. Beginning with the premise that there are differing forms of administration and that bureaucracy, in the classic formulation of Max Weber, is one of these, I develop a heuristic dichotomy between two types of administrators: stewards (who closely supervise goods and people) and bureaucrats (who process and control information). Bureaucracy is often linked to written records, but in the Central Andes alternative methods of record keeping were developed, such as the quipu or knotted string record. I argue that one alternative record-keeping device was an architectural form, the U-shaped structure. U-shaped structures are closely identified with the administrative architecture of the Chimu kingdom (ca. A.D. 850–1470) on the north coast of Peru. Four independent lines of argument demonstrate the development of bureaucracy from stewardship at Chan Chan, the capital of the Chimu kingdom. Brief comparisons are made between the Chimu administrative pattern and commodity and information flow in the earlier Huari and Tiwanku civilizations, and with the later Inka pattern. These comparisons show how record-keeping technology affects political economy and the strategy of expansion.
Late Classic Maya Water Management and Community Organization at Copan, Honduras
Authors: Davis-Salazar Karla L.
Published: February 2007

Recent research on prehispanic water management throughout the Americas has made significant contributions to our understanding of the diversity of adaptive systems employed in regions where water is seasonally scarce, such as the Maya Lowlands. Since much of this workfocuses on large-scale technologies, the political and economic consequences of these systems for smaller social units remain poorly understood. Social dynamics associated with less-intensive forms of water use and control are investigated at Late Classic (A.D. 600–900) Copán, in a water-rich setting of western Honduras. Ethnographic, iconographic, and archaeological datasets suggest that lagoons located in Copán’s urban residential sectors may have been conceptualized, utilized, and maintained as communal property with ancestral ties by the inhabitants of surrounding domestic groups. By shifting the scale of analysis from the polity to the community level, these lagoons can be viewed as forms of communal property that created an economic and ideological basis for local social integration but offered limited opportunity for the centralization of power through monopolistic control. Yet, toward the end of the Late Classic, the appropriation of water-related dynastic symbolism and possibly ritual seems to have provided nonroyal elites with a means for creating local social identities, which undercut and eroded royal authority.
First Report of a Newly Discovered Paleoindian Quarry Site on the Isthmus of Panama
Authors: Pearson Georges A.
Published: February 2007

An archaeological survey on the Azuero Peninsula in Panama has recently discovered a Paleoindian quarry/workshop at the base of a quartz outcrop. The Nieto site contains seldom-seen preforms and flake blanks that provide new information on early-stage reduction strategies used by Clovis-like point makers in the Neotropics. Finished tools recovered at the site include gravers, side scrapers, and large scraper planes. The production of flake blanks followed a core reduction and rejuvenation strategy already observed at other Paleoindian sites in Costa Rica and Florida. Although the quartz outcrop is located only a few kilometers away from better-quality sources of jasper and chert, Paleoindians appear to have preferred this translucent stone for their weaponry. This new information, when combined with late-stage production strategies previously recorded from other Panamanian sites, brings us closer to tracing a complete manufacturing trajectory for Clovislike points on the Isthmus. It is hoped that data from the Nieto quarry/workshop will eventually help archaeologists determine if the presence of the fluting technique in Central and South America is attributable to a migration of Clovis-related people or a technological diffusion among pre-established southerly populations.
Coexistencia de Cazadores Recolectores y Horticultores Tempranos en la Cordillera Andina de Chile Central
Authors: Cornejo B. Luis E. , Sanhueza R. Lorena
Published: February 2007

Recientes estudios en la cordillera andina de Chile Central nos han permitido identificar la coexistencia de dos modos de vida distintos en el mismo territorio durante el período Alfarero Temprano (350 a.C. a 900 d.C). Estos dos modos de vida corresponden, por un lado, a poblaciones de cazadores recolectores continuadores de la tradición Arcaica, especialmente en los aspectos económicos y en la tecnología lítica orientada curatorialmente, pero poseedores de algunas vasijas de cerámica adquiridas desde otros grupos propiamente alfareros y, por otro lado, a poblaciones semi-sedentarias con una economía hortícola, una desarrollada industria alfarera y una tecnología lítica principalmente expeditiva. Ambas poblaciones coexistieron e interactuaron en este territorio hasta fechas cercanas al 900 d.C.
Sak Tz’i’, a Classic Maya Center: A Locational Model Based on GIS and Epigraphy
Authors: Hernández Armando Anaya , Guenter Stanley P. , Zender Marc U.
Published: February 2007

The ancient Maya hieroglyphic inscriptions of the upper Usumacinta region record an intensive interaction that took place among its regional capitals. The precise geographic locations of some of these sites are presently unknown. Through the application of the Gravity Model within the framework of Geographic Information Systems (GIS), we present the probable locations and possible territorial extents of a few of these: Sak Tz’i’, Hix-Witz, and the “Knot-Site.” On this occasion, however, we concentrate our discussion on the role that the kingdom of Sak Tz’i’ played in the geopolitical scenario of the region. It is our belief that this case study constitutes a good example of how, through a conjunctive approach that integrates the archaeological with the epigraphic data, GIS can represent an excellent analytical tool to approach archaeological issues such as the political organization of the Maya Lowlands during the Late Classic period.
Geologic Water Storage in Precolumbian Peru
Authors: Fairley Jerry P.
Published: February 2007

Agriculture in the arid and semi-arid regions that comprise much of present-day Peru, Bolivia, and Northern Chile is heavily dependent on irrigation; however, obtaining a dependable water supply in these areas is often difficult. The precolumbian peoples of Andean South America adapted to this situation by devising many strategies for transporting, storing, and retrieving water to insure consistent supply. I propose that the “elaborated springs” found at several Inka sites near Cuzco, Peru, are the visible expression of a simple and effective system of groundwater control and storage. I call this system “geologic water storage” because the water is stored in the pore spaces of sands, soils, and other near-surface geologic materials. I present two examples of sites in the Cuzco area that use this technology (Tambomachay and Tipón) and discuss the potential for identification of similar systems developed by other ancient Latin American cultures.