bluuebunny/crossref_metadata_2025 huggingface dataset:
Relocating Labor: Sources from the Nineteenth Century
Authors: Rockel Stephen
Published: May 2006

It is generally recognized that during the period from ca. 1450 to 1900, when commercial relations between sub-Saharan Africa and the outside world were extended and strengthened, a wide range of systems and institutions for mobilizing labor were in use in different regions. I speak here of those operating beyond the primary locus of household and lineage. Such means of labor production and control ranged from chattel slavery to pawnship, corvées, various kinds of patronclient relations, bride service, cooperative labor, and also, in more and more contexts over time, wage labor. Slavery, of course, has received the attention of many scholars, as have some of the other categories. However the study of wage labor in precolonial times is still in its infancy.

For those wishing to pursue research on precolonial wage labor in Africa the lack of documentary sources has proved to be a significant barrier. The nature of proletarianized or semi-proletarianized wage labor in colonial societies or societies closely tied into the capitalist system usually demands of researchers that they look to sources of an official or institutional nature. For example, one can think of the records of companies, trade unions, benefit societies, colonial governments, courts, commissions of inquiry, and so on. But for precolonial Africa these types of documentary sources usually do not exist. This has led many scholars to say that the concept of wage labor is itself not useful when contemplating African labor systems before the onset of colonization. They point to the lack of a cash currency, continuing ties to the land, the temporary nature of much work, the absence of a bourgeoisie, apparent lack of worker consciousness, and so on. But there are other difficulties less related to such theoretical conceptions and generalizations about the supposed non-existence of wage labor which have severely taxed the most resolute historian, and help explain the dearth of written sources.
Archival Research in Antananarivo, Madagascar: The National Archives
Authors: Kaufmann Jeffrey C.
Published: May 2006

The Malagasy proverb “You can't catch a locust if your armpit is not close to the ground” (Ny valala tsy azo raha tsy andrian'elika) perhaps characterizes archival research in Antananarivo, the capital of Madagascar. There are at least eight research facilities with archival materials in town: the National Archives (Foiben'ny Arisivam-Pirenena Malagasy); the Academie Malgache; CIDST (Centre d'Information et de Documentation Scientifique et Technique); the National Library (Tranomboky-Pirenena); the University Library; and three church archives (American Lutheran, Norwegian Lutheran, and Catholic). In this paper I give some background information on the collections in the National Archives, outline how to use the facilities, provide an annotated bibliography of the finding aids there, and give some tips for one's stay in Antananarivo.

Madagascar's National Archives inherited many documents from the monarchical period. At the beginning of the colonial administration, the French deposited royal documents at the Queen's Palace (Rova) in Antananarivo. During their occupation they added documents from the territorial and central administrations. The whole collection was transferred to French headquarters before the Malagasy direction of Civil Affairs was created. On 1 March 1958 the Service des Archives de Madagascar was instituted. From then on, the archives have been under the jurisdiction of the head of government.

The National Archives are remarkable for their materials on the following topics: the history of the Malagasy people; their customs and practices; and their way of thinking that distinguishes them from the majority of other people. Moreover, the National Archives have collections that do not exist in other libraries, such as the Academie Malagasy and CIDST.
The J. S. M. Matsebula Collection at the University of Swaziland
Authors: Woodson Dorothy C.
Published: May 2006

On 24 November 1989 the Library at the University of Swaziland in Kwaluseni formally received a large portion of the papers and manuscripts of the eminent Swazi writer, historian, statesman, and current chief executive of the Swaziland National Trust, J. S. M. Matsebula. The deposit of these papers has formed the nucleus of a small, but interesting and rapidly expanding, Swaziana Collection and this contribution, it is hoped, will inspire other prominent Swazis and scholars of Swaziland similarly to deposit their materials. The preeminent anthropologist, Hilda Kuper, has recently offered her large and valuable collection of manuscripts and field notes to the University of Swaziland, and the elder statesman, J. J. Nquku, founder of the Swaziland Progressive Party (among other accomplishments), is preparing his personal papers for the Collection as well. Additionally, it has just been learned that the Swaziland Oral History Project materials will be transferred to the University of Swaziland from the University of the Witwatersrand.

James Shadrack Mkhulunyelwa Matsebula was born in 1918, outside Mbabane, the capital of Swaziland, into a family which has traditionally played a significant role in ritual Swazi royal life. The King's first wife is chosen from the Matsebulas and is known as laMatsebula. He was educated in Swaziland and South Africa and has written on a wide variety of topics in several genres and languages.
Masking Sunjata: A Hermeneutical Critique
Authors: Jansen Jan
Published: May 2006

Among the rich legacy of African oral traditions, the Sunjata epic is still one of the most complex phenonema, because it undoubtedly goes back to the times of Ibn Battuta, because of the limited variety between the available text editions, and because of its present-day popularity in sub-Saharan West Africa among people of all kinds of social background. In scholarly discussion, the epic has challenged many academics since Delafosse used the Sunjata epic as evidence for his reconstruction of the Mali empire as a thirteenth-century vast centralized polity. Although his views have been criticized since then, they have become part of history lessons at primary schools in Mali, the Gambia, Senegal, and Guinea. All these countries belong to the so-called “Mande,” an area inhabited by various ethnic groups that have close similarities in language, oral tradition, and social organization.

In the last decade History in Africa has given room to discuss the Sunjata epic, in particular in order to explore how data from the epic can be used as historical sources, and as what history for whom. Articles by David Conrad, Tim Geysbeek, Stephan Bühnen, Stephen Bulman, Kathryn Green, George Brooks, Ralph Austen, and myself come my mind. All these authors have treated the Sunjata epic as a text. This seems to be a logical and inevitable choice for the historian.

However, this approach implies a choice that limits the range of interpretations which can be made about the Sunjata traditions as a source for African history.
Radial growth of Fraxinus nigra in a Canadian boreal floodplain in response to climatic and hydrological fluctuations
Authors: Tardif Jacques , Bergeron Yves
Published: May 2006

Abstract. Stands of Fraxinus nigra (black ash) near Lake Duparquet (Abitibi region, NW Québec) are affected each year by spring or early summer flooding. The relationship between environmental factors and radial growth was studied in 50 100‐m2 quadrats laid out in five Fraxinus‐dominated stands. Response function coefficients showed that the weather in the year before growth, i.e. in the time of bud formation, had a strong influence on radial increment. Temperatures in April of the year before (year i‐1) and May (i‐ 1) were positively correlated with growth, while precipitation in April (i‐1), May (i‐1) and June (i‐1) were negatively correlated. Climatic factors positively associated with growth during the year of bud expansion were April (i) temperature and June (i) precipitation. Redundancy analysis showed that radial growth in Fraxinus nigra responded to variation in elevation and geomorphological landform. These differences in stand location and elevation were also related to different responses to climate. The sites most exposed to flooding responded much more to the negative impact of spring precipitation, while the more elevated sites were more responsive to summer precipitation. This study showed that black ash could be used for long term reconstruction of climatic and hydrological fluctuations.
Phytogeography of Italian deciduous oak woods based on numerical classification of plant distribution ranges
Authors: Bolognini Gloria , Nimis Pier Luigi
Published: May 2006

Abstract. 358 vascular plant species occurring in the deciduous oak woods of Italy were subdivided into 18 phytogeographical groups (chorotypes) through a numerical classification of their total ranges. The distribution patterns of the chorotypes are illustrated by chorograms, i.e. isopleth maps showing the joint distribution of species in Europe and surroundings regions. Except for Mediterranean species, which occur only occasionally in deciduous forests, the oak‐wood flora of Italy consists of four main phytogeographical elements, which have a similar incidence (ca. 25 % each): (a) narrow‐ranging, southern European species, (b) southeastern European species of submediterranean woodlands, (c) central‐European species, (d) widely distributed European species. The oak woods of Italy differ from their central‐European counterparts as to the relatively high floristic diversity, and in the presence of several narrow‐ranging taxa, centred in different refugial areas for forest vegetation during the glacial period. There is a relation between the distribution patterns of the chorotypes and their relative frequencies in different communities; the latitudinal and longitudinal extensions of the ranges reflect the thermic and hygric conditions of the communities. The oak woods of northern and southern Italy are phytogeographically well‐characterized; the former have a maximum of wide‐ranging, central European species, the latter host several narrow‐ranging taxa. The woodlands of central Italy have intermediate phytogeographical features, which is one of the main reasons for the difficulties in their syntaxonomical arrangement.
Effects of grazing, competition, disturbance and fire on species composition and diversity in grassland communities
Authors: Belsky A. Joy
Published: May 2006

Abstract.The effects of grazing, physical disturbance, interspecific competition, and fire on populations of individual species and on the structure and diversity of grassland communities were investigated in short‐, mid‐, and tall‐grasslands in the Serengeti National Park, Tanzania. The treatments included deep and shallow artificial disturbances, early dry‐season burning, and removal of dominant grass species from 2m2plots located inside and outside of large‐mammal‐proof exclosures. Species‐cover data were collected for five years and analyzed by analysis of variance and diversity indices.

In all three communities, protection from grazing and physical disturbance had greater impacts on species cover and diversity than removal of dominant species or fire. More species were significantly affected (positively and negatively) by disturbance and protection from grazing (50 ‐ 100%) than by species removals and fire (< 41%). In most cases, the cover of tall, perennial species increased following protection from grazing while the cover of annual and short, perennial species decreased. Over the five years of the study, vegetatively reproducing species benefited more than sexually reproducing species from protection from grazing, and tall rhizomatous species benefited more than tall stoloniferous species.

Disturbance caused annual and short perennial species to increase and tall perennials to decrease in cover. Following species removals, tall species were either unaffected or they increased in cover while some short species increased and others decreased in cover. Species diversity in two of the three communities decreased when the communities were protected from grazing but increased when disturbed, when dominant species were removed, and when burned.
Latitudinal pattern of mountain vegetation zonation in southern and eastern Asia
Authors: Ohsawa Masahiko
Published: May 2006

A new scheme of altitudinal and latitudinal vegetation zonation is proposed for eastern Asia. The latitudinal patterns of mountain vegetation zonation show a clear boundary at ca. 20°–30° N. For the tropical mountains south of 20° N, the altitudinal series includes tropical lowland, tropical lower montane, and tropical upper montane zones. For the temperate mountains north of 30° N, the series includes temperate lowland, temperate lower montane, and temperate upper montane zones. The mountains located between 20° and 30° N show a transitional zonation pattern; the lower two zones are comparable to the lower two of the tropical zonation (tropical lowland and tropical lower montane), and the upper two zones are comparable to those of the temperate zonation (temperate lower montane and temperate upper montane). The tropical upper montane zone is not found north of 20°–30° N, while the tropical lower montane zone reaches down to sea level and constitutes the temperate lowland zone. Thus the zonation between 20° and 30° N includes tropical lowland, tropical lower montane/temperate lowland, temperate lower montane, and temperate upper montane zones.

The latitudinal series of lowland rain forests follows the scheme of climatic division into tropical, subtropical/warm‐temperate, cool‐temperate and cold‐temperate, with a shift of the respective life forms, evergreen, evergreen notophyllous, deciduous, and evergreen needle‐leaved. The tropical lower montane forest can be correlated to the horizontal subtropical/ warm‐temperate zone. The temperate altitudinal and latitudinal zonations above 30° N are correlated and show an inclined parallel pattern from high altitudes in the south to low altitudes down to sea level in the north.
Plant nutrient changes in a semi‐arid Mediterranean shrubland after fire
Authors: Carreira J. A. , Niell F. X.
Published: May 2006

Abstract. Alkaline xeric soils from SE Spain weathered from kakiritized dolomitic rocks and subjected to recurrent fires, show phosphorus immobilization, low nutrient availability and high cation content, which might affect plant nutrition. Currently, Ulex shrubland, with a variety of dolomitophilous endemics, is colonizing eroded areas and replacing the original shrubland communities. Variation in nutrient content during post‐fire regeneration was studied in six species which differ widely in their successional status. All species showed a high consumption of nutrients immediately after the fire. A pattern of decline in internal nutrient levels, especially P, with time since fire was detected in mid‐to‐late successional shrubs: Juniperus oxycedrus, Genista spartioides, and to a lesser extent in Rosmarinus officinalis, a shrub species of intermediate successional status. This pattern of decline may represent a progressive change towards a metabolism with a low turnover along the age gradient. Early successional shrub species behaved in a different way. Cistus clusii showed a nutrient‐cumulative strategy, especially for P, across the fire‐age gradient. Ulex rivasgodayanus maximized internal N concentrations due to its symbiotic activity with N2‐fixing bacteria. Cistus and Rosmarinus held high cation levels in their tissues. The nutritional characteristics of these shrub species are seen as advantageous adaptations to the specific soil properties and disturbance regime of the area.
Long‐term vegetation changes in an Abies alba forest: natural development compared with response to fertilization
Authors: Becker M. , Bonneau M. , Le Tacon F.
Published: May 2006

Abstract. A fertilization experiment was set up in 1969 in a mature fir forest (Abies alba Mill.) in the Vosges Mountains in France, at an elevation of 800 m, on poor granites. It consists of 65 plots (250 m2), divided into 8 treatments: control, N, P, Ca, N+P, N+Ca, P+Ca, N+P+Ca. The quantities of fertilizers were: 200 kg.ha‐1 N, 150 kg.ha‐1 P2O5, 1500 kg.ha‐1 CaO. The humus type and the ground vegetation were described in 1969, and descriptions were repeated in 1989. Statistical analyses show that: 1. Liming, and liming only, has led to considerable alterations of the flora; the control plots are now dominated by Vaccinium myrtillus, a very acidophilous species, while the limed plots are dominated by Festuca altissima and numerous nitrophilous species. 2. Similarly, the humus layer of limed plots has changed from a mor or moder type to an acid mull type. That process might reflect an improvement of the biological activity and of the mineral nutrient cycle. 3. During the past 20 years, the unfertilized ground vegetation has changed, almost as expected from a moderate liming. Two possible causes of such a phenomenon are suggested: (a) a change in the light and temperature microclimate at the ground level, as a consequence of needle losses during the recent ‘forest decline’, which in turn could have improved organic matter mineralization; and/or (b) the chronic nitrogen deposition.
Measuring phenological variability from satellite imagery
Authors: Reed Bradley C. , Brown Jesslyn F. , VanderZee Darrel , Loveland Thomas R. , Merchant James W. , Ohlen Donald O.
Published: May 2006

Abstract. Vegetation phenological phenomena are closely related to seasonal dynamics of the lower atmosphere and are therefore important elements in global models and vegetation monitoring. Normalized difference vegetation index (NDVI) data derived from the National Oceanic and Atmospheric Administration's Advanced Very High Resolution Radiometer (AVHRR) satellite sensor offer a means of efficiently and objectively evaluating phenological characteristics over large areas. Twelve metrics linked to key phenological events were computed based on time‐series NDVI data collected from 1989 to 1992 over the conterminous United States. These measures include the onset of greenness, time of peak NDVI, maximum NDVI, rate of greenup, rate of senescence, and integrated NDVI. Measures of central tendency and variability of the measures were computed and analyzed for various land cover types. Results from the analysis showed strong coincidence between the satellite‐derived metrics and predicted phenological characteristics. In particular, the metrics identified interannual variability of spring wheat in North Dakota, characterized the phenology of four types of grasslands, and established the phenological consistency of deciduous and coniferous forests. These results have implications for large‐area land cover mapping and monitoring. The utility of remotely sensed data as input to vegetation mapping is demonstrated by showing the distinct phenology of several land cover types. More stable information contained in ancillary data should be incorporated into the mapping process, particularly in areas with high phenological variability. In a regional or global monitoring system, an increase in variability in a region may serve as a signal to perform more detailed land cover analysis with higher resolution imagery.
Diversity and phenology of weed communities in the Nile Delta region
Authors: Shaltout K. H. , El Fahar R. A.
Published: May 2006

This study evaluates the species diversity and phe‐nological behaviour of the weed communities associated with the common crops in the Nile Delta region (three winter crops: Egyptian clover, broad beans and wheat; and three summer crops: cotton, maize and rice). The weed communities of winter crops are of higher diversity than those of summer crops, presumably due to differences in sowing and weeding processes. The phenological sequences of the weed communities are, in most cases, closely related to those of the crops in which they occur. The correspondence between the crucial periods in the life cycle of the weed and the crop (seedling establishment and fruiting) often leads to severe competition.
Influence of landscape complexity and land management on woody plant diversity in northern Spain
Authors: Rescia A.J. , Schmitz M.F. , Martín de Agar P. , de Pablo C.L. , Atauri J.A. , Pineda F.D.
Published: May 2006

Abstract. Changes in land use, particularly the type of forest management, and their spatial pattern, especially woody plant diversity, were related to each other in an area in the Basque region (Spain). The number and diversity of boundaries between landscape patches is related to the development of the spatial complexity of the landscape, C(s), measured in bits and defined as: C(s) = H(b) H(l), where H(b) is the boundary diversity H(1) the spatial heterogeneity generated by these boundaries.

As to the vegetation types, changes in land use over the last 50 yr have resulted in a less diversified and more fragmented landscape, especially on a small scale. Forest plantation has become the predominant land use. The frequency of land use changes is studied regarding its influence on the present levels of woody plant diversity.
Influence of management on the seed production and seed bank of calcareous fen species
Authors: Schopp‐Guth Armin , Maas Dieter , Pfadenhauer Jörg
Published: May 2006

Abstract. The dynamics of the seed production and seed bank of two dominant perennial species of calcareous fens were investigated in response to different mowing frequency, fallow or pasture. The production of fertile shoots responded strongly to management practices. On sites where mowing alternated with fallow, autumn mowing led to an increase of fertile shoot density in Schoenus ferrugineus and a decrease in Molinia caerulea in the subsequent season. Repeated annual mowing after long‐term fallow raised the density in Schoenus and inhibited initiation of flowering shoots in Molinia. Seed set and viability were influenced mainly by climatic or other factors. Variation of seed production between sites and in consecutive years at the same site could thus be large.

The relationship between total seed production and seed bank was weak, but it improved when germination rates were included in the calculation. As the seed bank was generally smaller than the viable seed production, low survival and a high turnover of seeds in the upper soil layers is assumed for both species. Implications for recruitment strategies are discussed.
Influence of fire and soil nutrients on native and non‐native annuals at remnant vegetation edges in the Western Australian wheatbelt
Authors: Hester A. J. , Hobbs R. J.
Published: May 2006

Abstract. The effect of fire on annual plants was examined in two vegetation types at remnant vegetation edges in the Western Australian wheatbelt. Density and cover of non‐native species were consistently greatest at the reserve edges, decreasing rapidly with increasing distance from reserve edge. Numbers of native species showed little effect of distance from reserve edge. Fire had no apparent effect on abundance of non‐natives in Allocasuarina shrubland but abundance of native plants increased. Density of both non‐native and native plants in Acacia acuminata‐Eucalyptus loxophleba woodland decreased after fire. Fewer non‐native species were found in the shrubland than in the woodland in both unburnt and burnt areas, this difference being smallest between burnt areas. Levels of soil phosphorus and nitrate were higher in burnt areas of both communities and ammonium also increased in the shrubland. Levels of soil phosphorus and nitrate were higher at the reserve edge in the unburnt shrubland, but not in the woodland. There was a strong correlation between soil phosphorus levels and abundance of non‐native species in the unburnt shrubland, but not after fire or in the woodland. Removal of non‐native plants in the burnt shrubland had a strong positive effect on total abundance of native plants, apparently due to increases in growth of smaller, suppressed native plants in response to decreased competition. Two native species showed increased seed production in plots where non‐native plants had been removed. There was a general indication that, in the short term, fire does not necessarily increase invasion of these communities by non‐native species and could, therefore be a useful management tool in remnant vegetation, providing other disturbances are minimised.
Spatial patterns of trees in natural forests of East‐Central Europe
Authors: Szwagrzyk Jerzy , Czerwczak Marek
Published: May 2006

The analysis of spatial patterns is one of the ways to estimate the role of competition among trees in forest dynamics. Three hypotheses concerning distribution patterns in old‐growth stands were tested: (1) fine‐scale spatial patterns of trees are regular; (2) patterns do not differ significantly from a random distribution, and (3) spatial patterns at larger scales are clumped because of site heterogeneity. Old‐growth forest stands in Poland and the Czech Republic were analysed with a modified RipleyKfunction, using distribution maps of tree stems.

Fine‐scale spatial patterns (with distances among trees not exceeding 15 m) were usually intermediate between random and regular. Trends towards a regular distribution occurred more often among dead than among live individuals. No significant relationships between tree species were found at smaller scales; however, at larger scales (distances from 15–25 m) negative associations between some species were found. This reflects site heterogeneity rather than any direct influence of one tree species upon another.
Resource availability at three presumed stages of a heathland succession on the Lüneburger Heide, Germany
Authors: Leuschner Ch.
Published: May 2006

Abstract. The availability of maj or plant resources was investigated in three vegetation types that were assumed to represent different stages of a secondary succession on heathland on the Lüneburger Heide, northwestern Germany. Canopy transmission and absorption of photosynthetically active radiation (PAR), soil‐water availability, and nutrient (Ca, K, Mg, N, P) availability were monitored with high spatial and temporal resolution in (1) a Calluna vulgaris heathland, (2) a pioneer birch‐pine forest and (3) a late‐successional oak‐beech forest, situated close to each other on comparable geological substrate (diluvial). Mean fractional transmission of PAR during summer decreased from 0.48 in the heathland to 0.04 in the oak‐beech forest while the fractional canopy absorption increased from 0.49 to 0.92.

Soil‐water availability as indicated by the soil‐water potential, was significantly influenced by differential canopy interception loss and characteristic rooting patterns in the three vegetation types. Annual mean nutrient concentrations in the equilibrium soil solution were similar or, for some elements, increased from the heathland to the birch‐pine and the oak‐beech forest despite a growing demand. A marked increase was found for the total nutrient pools in the soil‐organic layer between early and late successional vegetation types. On the poor glacial parent material, nutrient pools seem to be strongly dependent on stand productivity and litter production which increased with succession. Thus, for nutrients, facilitation seems to be important in this type of succession.
Altitudinal pattern of vegetation variation on Tenerife
Authors: Fernández‐Palacios José María , de Nicolás Juan Pedro
Published: May 2006

Abstract. The variation in structure and floristic composition of the vegetation of Tenerife is related to different environmental factors. 200 sample plots, stratified according to altitude, exposure to wind, kind and age of parent rock, inclination and degree of disturbance were analysed throughout the island. The resulting data were analysed using univariate statistics (altitudinal distribution profiles of the more frequent species) and multivariate methods (Correspondence, Cluster and Pattern Analysis).

Altitude, exposure to wind and, to a lesser extent, disturbance were found to be the major determinants of vegetational variation, whereas parent rock and inclination were less important. Ordination results show a continuum in structural and floristic variation of the vegetation with species distributions varying continually along the altitudinal gradient. Nevertheless, altitudinally bound plant community types were recognized with Cluster Analysis. Vegetational discontinuities, which were also detected by pattern analysis, are more evident on the windward slope of the island; they have been attributed to the existence of a major underlying environmental discontinuity the ‘cloud sea’‐which is associated with a climatic inversion. On the leeward slope, beyond the influence of the cloud sea, discontinuities are less evident and vegetational variation seems to be closer to a coenocline, i.e. a vegetational continuum.
The vegetation of roadside verges with respect to environmental gradients in southern New Zealand
Authors: Ullmann Isolde , Bannister Peter , Wilson J. Bastow
Published: May 2006

Abstract. A survey of the vegetation of roadside verges was made across the southern part of the South Island of New Zealand. Samples were taken at 10‐km intervals along selected roads providing a climatic range from the suboceanic conditions of the east coast into semi‐arid Central Otago, and from Central Otago through the Southern Alps to the hyper‐oceanic areas of high rainfall on the west Coast. The variation in the floristic composition is associated mainly with variation in rainfall, continentality, altitude, soil acidity, soil organic matter, and presence of forest. Sites in the arable and pastoral regions on the eastern side of the Southern Alps support a herbaceous vegetation consisting mostly of exotic species of European origin, with a few native grasses scattered through the drier and less fertile sites. A greater proportion of native species is found at higher altitudes. Roadside vegetation in the area of high rainfall to the west is characterized by indigenous ferns and woody species, although vegetation adjacent to cleared areas is more similar to that on roadsides adjacent to farmland on the east coast. The pattern of distribution of both native and exotic species is strongly related to altitudinal and climatic gradients, and the environmental responses of the exotic species are similar to those recorded in Europe. This suggests a colonization of all available sites by the exotic species, despite the relatively short time since their introduction to New Zealand, rather than an incomplete invasion.
In situregeneration ofPinus strobusandP. resinosain the Great Lakes forest communities of Canada
Authors: Carleton T.J. , Maycock P.F. , Arnup R. , Gordon A.M.
Published: May 2006

Abstract.Two extensive forest vegetation survey datasets are explored, using ordination and classification, for evidence ofin situregeneration byPinus strobus(Eastern white pine) andP. resinosa(Red pine). Ordination of tree species contributions to total basal area in 320 upland northern hardwood‐ conifer stands produced distinct stand groups forP.banksiana, P. resinosa,P. strobusand mesic hardwoods in an ascending sequence along the first axis.Quercus rubra(red oak),Q. alba(white oak) and tolerant conifer groups formed segregates from the hardwood complex along the second axis.P. strobusmixes with all other forest types, butP. resinosais restricted to its own group. Seedlings and trees ofP. strobusare more abundant than saplings, which are restricted to the pine and oak forests. Therefore, seed production, dispersal and seedling establishment seem to be less of a barrier toin situregeneration byP. strobusthan subsequent survival and growth.

Canonical correspondence analysis of 170 pine‐dominated stands from the Canadian Shield of Ontario, in which tree species variables are segmented into height‐class pseudo‐ species, yielded no linear relationship between environmental features or stand structure and seedling densities ofP. strobus. However, total tree basal area appears to impose an upper limit to seedling density on the forest floor. Strong correlations emerged between pine seedling density and understorey vegetation. Stand classification of the understorey vegetation, using constrained indicator species analysis, yielded distinct high and low seedling groups. Low pine seedling density was associated with abundant broadleaved shrubs, herbs and seedlings as well as feathermosses and tolerant conifers. High seedling density could not be ascribed to the presence of seedbed taxa, such asPolytrichum, but is ascribed to the absence of competition and other forms of inhibition in the understorey vegetation and down through the canopy profile.In situregeneration ofP. strobusdoes, therefore, occur but conditions over the forest landscape are largely restrictive.
Establishment and growth of Quercus floribunda seedlings after a mast year
Authors: Negi A.S. , Negi G.C.S. , Singh S.P.
Published: May 2006

Abstract. Population dynamics, mortality factors, growth and dry weight changes in Quercus floribunda seedlings were studied to determine the implication of sun and shade microsites and the role of mast years on regeneration and maintenance of oak forests in Kumaun Himalaya. The number of seedlings was significantly greater at the sun microsites, but seedling survival was not, as ground herbage clearance at sun microsites accounted for 53.5% mortality. Insect herbivores (e.g. acorn worm) were also one of the major mortality factors. At both microsites, most mortality was encountered between June and August. The initial seedling height at sun microsites was significantly lower compared to shade microsites. Seedlings at sun microsites were superior in terms of number of leaves and peak dry weight. Dry mass allocation in seedling components and root:shoot ratio was similar at both microsites. The study shows the importance of sun microsites and of masting in the potential for regeneration and expansion of Q. floribunda forests.
Successional status of trees in gallery forest along the river Rhine
Authors: Schnitzler Annik
Published: May 2006

Abstract. 20 alluvial forest stands of different ages along the river Rhine in central Alsace, France, are described. A natural complex landscape occurs which is formed by erosion activity of the river. Recent human impact (canal construction, cutting) has affected river hydrology: flooding is eliminated over large areas and the underground water levels are stabilized. The forest vegetation varies in species diversity and structure, from young pioneer to older, mid‐successional forests. The forests were classified into four associations: Salici‐Populetum nigrae, Ligustro‐Populetum nigrae, Fraxino‐Populetum albae and Querco‐Ulmetum minoris. The first three communities are ‘softwood’ because of the dominance of Salix and Populus, the fourth, dominated by Quercus robur, Fraxinus excelsior and Ulmus minor, is ‘hardwood’.

Differences in structure, species composition and diversity in 10 widely varying stands in 30‐yr and 150‐yr old forests are quantified and interpreted in relation to the processes and gradients (moisture and texture) involved.

A model of forest succession is developed as follows:

Whatever the topographic level, Salix and Populus species are the most competitive in colonizing bare sediments.

Under natural conditions, pioneer softwoods are generally replaced by hardwoods in less than 100 yr.

Old Querco‐Ulmetum is basically the terminal stage of the alluvial succession.

Old softwood forests result from an interruption of the natural course of succession. Softwoods may be an intermediate or late‐successional phase depending on the interruption.

Successional processes change according to hydrological and edaphic gradients.

Allogenic processes of flooding are fundamental in the space‐time species pattern.

Allogenic processes are responsible for the high species and community diversity.
Effects of reindeer grazing on understorey vegetation in dry Pinus sylvestris forests
Authors: Väre Henry , Ohtonen Rauni , Oksanen Jari
Published: May 2006

Abstract. Data on floristic composition and environmental variables were collected in floristically homogeneous oligotrophic pine (Pinus sylvestris) forests with heath‐like under‐ storey vegetation in eastern Fennoscandia, and ordinated by non‐linear multidimensional scaling (NMDS) in order to study the effect of lichen grazing by reindeer on the understorey vegetation. The study sites included areas with varying grazing pressure, as well as 50‐yr old grazing exclosures. Sites rich in respectively bryophytes and lichens were placed at opposite ends of the ordination axes, and heavily grazed sites were placed in between them. Reindeer grazing increased the abundance of bryophytes, especially Dicranum spp. and Pleurozium schreberi. Grazing changed the vegetation to the extent that it resembled more mesotrophic sites, but this did not show any relationship with tree volume or other site productivity indicators. This was observed both in the ordination and, in a more compelling way, when exclosures with adjacent grazed areas were compared. No such signs were evident at ungrazed sites, where especially Cladina spp. spatially replace Cladonia spp. and tiny bryophytes like Barbilophozia spp., Polytrichum spp. and Pohlia nutans during succession. Cladina stellaris had almost disappeared from the most intensively grazed sites.

The soil at ungrazed sites was characterized by high Al and Fe concentrations and bryophyte‐rich sites by high Mn concentrations. Shannon's diversity index, depth of humus layer and proportion of bare ground also increased in sites getting richer in bryophytes.
The importance of Olneya tesota as a nurse plant in the Sonoran Desert
Authors: Suzán Humberto , Nabhan Gary P. , Patten Duncan T.
Published: May 2006

Abstract. The function of Olneya tesota (ironwood) as a nurse plant and habitat modifier species in the Sonoran Desert was evaluated at five study sites (using 75 250‐m2 sample plots) from Bahia Kino, Sonora to Organ Pipe Cactus National Monument, Arizona. Beneath the canopy of O. tesota trees 75 perennial plant species were found. A principal component ordination of the plots created three groups: southern, perturbed and protected sites. A strong triple association of columnar cacti, big shrubs with berry type fruits and O. tesota was detected. The relationships of Lophocereus schottii and Peniocereus striatus with O. tesota were studied in more detail. Significant differences in soil surface temperatures and stem temperatures of P. striatus were detected beneath the shade of O. tesota trees compared with soils and plants in open spaces. Olneya tesota must be considered as a habitat modifier species with ecological and conservational importance to the plant communities in the Sonoran Desert.
Dynamics of understory vegetation in an old‐growth boreal coniferous forest, 1988–1993
Authors: Økland Rune Halvorsen , Eilertsen Odd
Published: May 2006

Abstract. Understorey vegetation changes in a South Norwegian old‐growth coniferous forest were studied between 1988 and 1993 in 200 1‐m2 vegetation plots. Our aims were to quantify the amount of between‐year compositional change, and to elaborate the environmental basis for long‐term vegetation change, including the previously identified gradient structure with a major gradient related to topography (and soil nutrient status and soil depth) and a minor gradient reflecting paludification and canopy coverage.

Species richness (yearly mean and cumulative species number) and change in species richness differed between vascular plants and cryptogams, and between forest types. The number of vascular plant species decreased in pine forest in dry years; bryophyte species number increased in spruce forest.

Statistically significant vegetation change, as tested by constrained ordination (CCA) with time as the constraining variable, is demonstrated for most one‐year periods and for the five‐year period in most forest types. Vegetation change along identified gradients, measured as plot displacement along DCA ordination axes, also occurred. The magnitude of year‐to‐year vegetation change was related neither to forest type nor to one‐year period; different responses to climatic and environmental change were observed in each forest type. The largest average displacement observed, from medium‐rich spruce forest towards poor spruce forest, was interpreted as a long‐term trend. Humus‐layer pH decreased by ca. 0.25 units from 1988 to 1993, most strongly in medium‐rich spruce forest where exchangeable Ca decreased and Al and Mn increased strongly.

Our study supports the hypothesis that vascular plants show a long‐term and broad‐scale response to soil acidification. Change in bryophyte composition is linked to some very long growing‐seasons. Detailed analysis of short‐term vegetation dynamics enhances the interpretation of long‐term changes and stresses the complementarity of univariate and multivariate methods in the analysis of vegetation change.
Species diversity in plant communities on ultramafic soils in relation to pine afforestation
Authors: Chiarucci A.
Published: May 2006

Abstract. The influence of pine afforestation on the species diversity of plant communities on ultramafic substrate was investigated in an area of Tuscany, central Italy, by means of species‐area relationships, plant unit area, the Gini coefficient and the pattern of the index of Jaccard in relation to plot size. The species‐area relationship was found to best fit the semilogarithmic model. Contrary to the available data for temperate ecosystems, tree canopy cover was found to increase the α‐diversity of the understorey vegetation and its cover. The nutrient input due to the pine canopy caused an increase in the abundance of the grass Festuca inops — which was already present in the community — and subsequently the spread of several grassland species leading to a reduction in dominance concentration and to the formation of a species‐rich grassland. The pine cover caused a decrease in floristic resemblance between plots, especially when the canopy cover is scattered. The increase in species richness found under the pine canopy, where the metal content in the soil is higher, suggests that potentially toxic metals are not the most limiting factor in Tuscan ultramafic soils. The typical poorness of vegetation on ultramafic soils should be first of all related to hydrological and nutritional stresses.
Determination of plant species cover by means of image analysis
Authors: Dietz Hansjörg , Steinlein Thomas
Published: May 2006

Abstract. A method is described for the determination of plant species cover in herbaceous plant communities by means of image analysis. It is a computerized extension of the quadrat‐charting method. The method was tested with four different computer systems for three different vegetation types, a shady lawn, a pioneer vegetation and a forest floor. We compared the results with vertical point‐intercept analyses of the same stands. Image analysis revealed a high accuracy of the method ranging from < ± 1 to about ± 2% cover depending on the dominance of the species being analysed. The method is particularly suitable for the analysis of low herbaceous or unsaturated vegetation, dominance stands of broad‐leaved plant species and for the analysis of cover changes in permanent plots.
Seed population dynamics on badland slopes in southeastern Spain
Authors: García‐Fayos P. , Recatalá T.M. , Cerdá A. , Calvo A.
Published: May 2006

Abstract.The dynamics of seed population on slope surfaces were studied to test the hypothesis that the lack of vegetation on badlands is caused by seed removal by erosion. The initial soil seed bank and two years of seed rain and seed removal by erosion were estimated in two small catchments, and a seed balance was constructed. In addition, six rainfall simulation experiments were performed to test the susceptibility of seeds to be removed by overland flow. A variety of soil surface conditions, rainfall characteristics and plot sizes were used in these experiments.

Soil seed bank densities are low, but enough for the development of plant cover. Seed losses due to erosion after natural rains were low (< 13 %), and in agreement with seed losses from simulated rainfall experiments. After two years, seed inputs in the seed rain were greater than seed outputs through seed removal, which resulted in a continuous increase in the numbers of seeds in the soil bank. These results point out that seed removal by erosion is not the key factor explaining the lack of vegetation on badlands. It is suggested that other factors, such as those related to seed germination and seedling survival, may play an important role.
Interactive effects of fire and grazing on structure and diversity of Mediterranean grasslands
Authors: Noy‐Meir Imanuel
Published: May 2006

Abstract. The separate and combined effects of fire and cattle grazing on structure and diversity of productive Mediterranean grasslands in northern Israel were examined within a set of climatically and edaphically similar sites. Cover and height of green and dry plants in winter, and species richness and diversity in spring, were measured in paired transects on both sides of cattle fences, and on both sides of boundaries of both incidental and experimentally lit fires.

Early in the first growing season after a fire, plant cover as well as height of green plants were reduced, compared to unburnt grassland. These structural effects of fire were similar to the effects of grazing, but they were greater in ungrazed than in grazed grasslands, indicating a fire‐grazing interaction. The effects of fire were considerably attenuated in the second growing season after the fire.

Species richness and diversity tended to be higher in grazed than in adjacent ungrazed grasslands. Richness consistently increased after a fire only in grazed grasslands with a strong perennial component. In ungrazed grasslands, and in predominantly annual grasslands, fires reduced species richness and diversity at least as often as they increased it.

Fire and grazing should be regarded as two agents with distinct and interactive effects on the community, rather than as two alternative mechanisms of a general disturbance factor.
Long‐term post‐fire changes in the northeastern boreal forest of Quebec
Authors: De Grandpré Louis , Morissette Jacques , Gauthier Sylvie
Published: May 2006

Abstract. Natural dynamics in the boreal forest is influenced by disturbances. Fire recurrence affects community development and landscape diversity. Forest development was studied in the northeastern boreal forest of Quebec. The objective was to describe succession following fire and to assess the factors related to the changes in forest composition and structure. The study area is located in northeastern Quebec, 50 km north of Baie‐Comeau. We used the forest inventory data gathered by the Ministère des Ressources naturelles du Québec (MRNQ). In circular plots of 400 m2, the diameter at breast height (DBH) of all stems of tree species greater than 10 cm was recorded and in 40 m2 subplots, stems smaller than 10 cm were measured. A total of 380 plots were sampled in an area of 6000 km2. The fire history reconstruction was done based on historical maps, old aerial photographs and field sampling. A time‐since‐fire class, a deposit type, slope, slope aspect and altitude were attributed to each plot. Each plot was also described according to species richness and size structure characteristics. Traces of recent disturbance were also recorded in each plot. Changes in forest composition were described using ordination analyses (NMDS and CCA) and correlated with the explanatory variables. Two successional pathways were observed in the area and characterized by the early dominance of intolerant hardwood species or Picea mariana. With time elapsed since the last fire, composition converged towards either Picea mariana, Abies balsamea or a mixture of both species and the size structure of the coniferous dominated stands got more irregular. The environmental conditions varied between stands and explained part of the variability in composition. Their effect tended to decrease with increasing time elapsed since fire, as canopy composition was getting more similar. Gaps may be important to control forest dynamics in old successional communities.