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1.
Per Lagerås 《Vegetation History and Archaeobotany》1996,5(3):215-228
Pollen analysis was carried out on gyttja from the small lake Femtingagölen in the Småland Uplands, southern Sweden. The interpretation of the pollen diagram focused on land-use history and comparisons were made to archaeological and historical information from the area. An absolute chronology, based on AMS dates from terrestrial plant macrofossils, was complemented by inferred dates. The pollen analytical data suggest interference with the woodland cover from ca. 1700 B.C. onwards. Intensified grazing and forest clearances resulted in semi-open pastures between ca. A.D. 400–600 which was followed by forest regeneration (chronology based on AMS 14C dates and cross-correlation with other well dated profiles). The landscape became more open again between A.D. 800 and 1400. Animal husbandry was complemented by small-scale shifting cultivation during the Iron Age. Permanent arable fields were probably not introduced until the Late Iron Age or the Middle Ages. Hordeum and Triticum were grown during the Iron Age, Hordeum, Triticum, Secale and Cannabis sativa during the Middle Ages and early Modern time, and Hordeum and Avena in the recent past. Sandy and silty soils, where stone clearance was not necessary, have probably been used for cereal growing in prehistoric and historic time. 相似文献
2.
The influence of pre-industrial animal husbandry on the boreal forest in south-central Sweden has been studied by pollen
and charcoal analyses of peat profiles from two mires in the vicinity of a shieling site. The impact of farming on the local
vegetation development is demonstrated from cal. A. D. 1300–1500 in three ways: forest clearance and cultivation of cereals
at the local shieling site; alterations of hydrology and vegetation, such as an increase in Cyperaceae, at mires used for
hay production; changes in the composition in the surrounding forest, with decreasing proportions of Betula, Picea and boreo-nemoral broadleaved trees and a consequent increase in Pinus, due to grazing and a change of fire regime. Similar alterations to the forest vegetation are noted at other sites in central
and northern Sweden during the last thousand years, when the system of using shielings became more widespread. Hence, early
animal husbandry is demonstrated to have had a regional impact on the long-term boreal forest development, replacing the original
mixed deciduous-coniferous forest with Pinus dominated forest.
Received November 27, 2001 / Accepted June 20, 2002
Correspondence to: Marie Emanuelsson 相似文献
3.
Influence of human impact and bedrock differences on the vegetational history of the Insubrian Southern Alps 总被引:1,自引:0,他引:1
E. Gobet W. Tinner P. Hubschmid I. Jansen M. Wehrli B. Ammann L. Wick 《Vegetation History and Archaeobotany》2000,9(3):175-187
Vegetation history for the study region is reconstructed on the basis of pollen, charcoal and AMS14C investigations of lake sediments from Lago del Segrino (calcareous bedrock) and Lago di Muzzano (siliceous bedrock). Late-glacial forests were characterised byBetula andPinus sylvestris. At the beginning of the Holocene they were replaced by temperate continental forest and shrub communities. A special type of temperate lowland forest, withAbies alba as the most important tree, was present in the period 8300 to 4500 B.P. Subsequently,Fagus, Quercus andAlnus glutinosa were the main forest components andA. alba ceased to be of importance.Castanea sativa andJuglans regia were probably introduced after forest clearance by fire during the first century A.D. On soils derived from siliceous bedrock,C. sativa was already dominant at ca. A.D. 200 (A.D. dates are in calendar years). In limestone areas, however,C. sativa failed to achieve a dominant role. After the introduction ofC. sativa, the main trees were initially oak (Quercus spp.) and later the walnut (Juglans regia). Ostrya carpinifolia became the dominant tree around Lago del Segrino only in the last 100–200 years though it had spread into the area at ca. 5000 cal. B.C. This recent expansion ofOstrya is confirmed at other sites and appears to be controlled by human disturbances involving especially clearance. It is argued that these forests should not be regarded as climax communities. It is suggested that under undisturbed succession they would develop into mixed deciduous forests consisting ofFraxinus excelsior, Tilia, Ulmus, Quercus andAcer. 相似文献
4.
Previous Land Use Alters the Effect of Climate Change and Facilitation on Expanding Woodlands of Spanish Juniper 总被引:1,自引:0,他引:1
In Mediterranean–continental regions, changes in land use are leading to the expansion of valuable habitats like endemic Juniperus thurifera woodlands, but the impact of reduced rainfall, due to climate change, on this expansion remains uncertain. We assessed the
early performance of J. thurifera in different global change scenarios with and without facilitation. Saplings were transplanted in three ecosystems types
with different previous land use (woodlands, former agricultural fields, and former livestock pastures), microhabitats (open
vs. understory of adult trees) and were subjected to two watering regimens. We characterized the abiotic environment and measured
survival, growth and two ecophysiological parameters. Former livestock pastures were the least favorable ecosystem, where
the nursing effect was greatest. Former agricultural fields had the highest survival, but were more sensitive than woodlands
to water scarcity. Reduced rainfall decreased photochemical efficiency, particularly in the least favorable scenarios, but
did not affect survival. Water use efficiency enhanced growth under the canopy, but not in the open, whereas photochemical
efficiency enhanced growth and survival more in the open. Facilitation was critical for effective recruitment in the harshest
scenarios: former livestock pastures and reduced rainfall. Comparison with previous studies suggests that establishment depends
on infrequent wet episodes. In Mediterranean ecosystems, changes in land use and climate change are leading to woodland expansion
due to the modulating effect of facilitation of the oncoming adverse drier conditions. Nevertheless, the positive effect of
facilitation and the negative impact of aridity on tree recruitment are strongly influenced by previous land-use history. 相似文献
5.
Corinna Brunschön Torsten Haberzettl Hermann Behling 《Vegetation History and Archaeobotany》2010,19(3):191-206
A lake sediment record from Laguna Campana at 2,488 m a.s.l. in the eastern Ecuadorian Andes allows the reconstruction of
local environmental conditions over the past ~500 years. A high-resolution multi-proxy approach using pollen, spore, charcoal
and XRF analyses provides information about lake genesis, hydrological variations and the development of the surrounding vegetation.
Results suggest that Laguna Campana originated from a landslide, which are naturally common and anthropogenically promoted
in the study area. Human activities, e.g. deforestation or slash and burn cultivation, impacted the local vegetation development
and biodiversity during the recorded period. After a first dense layer of pioneer grasses developed on open soil around the
small lake, successional stages of secondary upper mountain rainforest forest mainly composed of Alnus and Weinmannia were observed. The record shows no signs of dense forest regeneration but rather open vegetation with trees and a grassy
understory. Especially since ca. a.d. 1980, the proportion of forest in the area was reduced, most probably by fire use for pastures, cultivation and wood extraction.
Hydrological variability was derived from differences in minerogenic input and variations in Botryococcus braunii and Sphagnum occurrence. After wettest conditions at the study site, probably triggering the landslide, humid conditions persisted until
a time of drier conditions between a.d. 1900 and 1960. A subsequent return to wetter conditions was observed over the last decades. XRF analyses suggest an increase
in deposition of atmospherically derived lead since the formation of the lake. 相似文献
6.
Pollen records from a small lake and a small peatland at Ire in northern Blekinge, Sweden, reveal that until a.d. 300 there was a mixed deciduous type of woodland dominated by Quercus, Tilia and Corylus, with Betula, Pinus, Populus, Fraxinus, Ulmus and Acer as important constituents. The first, but weak, signs of human influence on the vegetation are detected around 2300 b.c. At this time, the area was probably used for woodland grazing. The regional expansion of Fagus occurred around 100 b.c.–a.d. 200, and later, at about a.d. 500, woods dominated by Fagus were common in the area. Around a.d. 600–700 an isolated farmstead may have been established in the area, as single pollen grains of Secale (rye) were found. This farmstead may represent the first permanent settlement in the area. A more widespread opening of the vegetation occurred around a.d. 1000, probably as an effect of a more pronounced use of the area, and an expansion of settlements in the region. The openness of the area seems to have peaked around a.d. 1400–1800, and during this period the vegetation was highly fragmented with small stands of woodland, intensively grazed pastures, and arable fields where Secale and Triticum were mainly cultivated. Around a.d. 1600 Fagus pollen percentages sharply decrease, most probably caused by a deliberate and selective felling of beech trees for the production of potash, which consumed enormous amounts of wood. Picea seems to have been established around a.d. 1600, but it did not become a regional dominant until the first part of the 20th century, when land use decreased and it became favoured by forestry. 相似文献
7.
The cultural landscape development of a farming community in western Norway was investigated through pollen analyses from
a lake and a peat/soil profile. The pollen record from the lake indicates that there was a decrease in arboreal pollen (AP)
by the end of the Mesolithic period (ca. 4200 cal b.c.), and that a substantial forest clearance occurred during the Bronze Age (ca. 1500 cal b.c.). The latter, together with grazing indicators and cereals, suggests a widespread establishment of farming. At the beginning
of the Roman Iron Age there is an increase in heath communities. The pollen diagram from the peat/soil profile shows the forest
clearance in the Bronze Age more clearly than the lake profile. This local pollen diagram is compared with modern pollen samples
from mown and grazed localities in western Norway. Both analogue matching and ordination (PCA) indicate that the site was
characterised by pastures and cereal fields from the Late Bronze Age to the Late Iron Age. An expansion of cereal cultivation
took place during the Pre-Roman Iron Age, and an arable field was established at the site after ca. a.d. 800. This investigation illustrates the potential of selecting pollen sites reflecting different spatial scales, and complements
the cultural history of the area as inferred from archaeological and historical records. 相似文献
8.
Abandonment and Expansion of Arable Land in Europe 总被引:4,自引:0,他引:4
Abandonment of arable land is often assumed to happen mostly in marginal areas where the conditions for arable cultivation
are relatively unfavorable, whereas arable expansion is expected to occur mostly in areas with favorable conditions. This
assumption, used in many land-use change forecasts, was never properly tested, mainly because the relatively short period
of full-coverage land-use inventories did not allow a systematic analysis of the phenomena. With the recent release of CORINE
2006 this has changed. In this article, we explore the typical locations of abandonment and expansion of arable land in Europe
during the period 1990–2006 by means of logistic regressions. More specifically, we test whether or not locations of abandonment
and expansion can be inferred from the location characteristics of arable land in 1990. If the above assumption holds, this
should be the case. We demonstrate that although arable expansion indeed happens in locations that resemble the bulk of arable
land in 1990 (the presumably favorable locations), arable abandonment does not necessarily happen in locations that resemble
the bulk of uncultivated land (that is, the presumably unfavorable locations). In other words, the assumption does not hold.
Particularly, areas close to the road network were found to be associated with both high abandonment rates and high expansion
rates, which suggest that abandonment is not limited to areas that are marginal in terms of agricultural production. 相似文献
9.
Trade-offs in nest site selection in coastal populations of Lapwings Vanellus vanellus 总被引:1,自引:1,他引:0
In coastal populations of Lapwings Vanellus vanellus in southwestern Sweden, arable fields predominated as foraging habitat before laying. Females caught more large prey items on arable fields and shores than on pastures. Close to egg laying, females foraged mainly near their future nest sites. Arable land and pastures were used to a similar extent for nesting. We found no difference in nest predation between habitats. Egg volume varied among females and was correlated with wing-length, body mass and condition. Mean egg volume also was positively correlated with feeding time on arable land before laying. Pairs nesting on arable fields therefore generally produced larger eggs than those on pastures. The distances between nests and chick foraging areas, however, were significantly longer for birds nesting on arable land than for those on pastures. Moreover, in 2 of 3 years, the proportion of hatched chicks that survived until fledging was negatively correlated with this distance. There was no difference in chick survival between broods hatched on arable fields and pastures. We suggest that nest site selection and offspring production involve a trade-off between the benefits of nesting close to rich feeding grounds for adults and the costs of moving long distances between nest sites and chick-rearing areas. 相似文献
10.
Questions: 1. What is the scale and extent of spatial variability in factors affecting Betula invasion of heaths? 2. How much effect does each factor have on within‐patch patterns of invasion? 3. How can this understanding aid in managing Betula invasions? Location: Lowland heath of southern England. Methods: Determinants of Betula (both B. pubescens and B. pendula) invasion: biomass density, necromass density, mean vegetation height, P‐availability, soil water content and total Betula seed bank density, were measured at two sites on a 5‐ha sampling grid. Spatial pattern was assessed using geostatistics. Contributions of each determinant to within‐site heterogeneity in predicted Betula seedling densities were estimated by varying variables over their full and interquartile ranges in a statistical model derived from experimental data. Results: Salient spatial trends were revealed: strong autocorrelation over distances of < 50 m for soil factors and more extensive autocorrelation (0 to > 150 m) in vegetation variables and Betula seed bank densities. The latter resulted in single across‐site gradients, the former small, distinct patches. All patterns were overlain with variance that was present at distances of < 17.6 m. Variables displaying spatial pattern also accounted for within‐site heterogeneity in predicted Betula seedling densities but their relative contribution to this varied between sites. Conclusions: Identifiable spatial autocorrelation in factors controlling patch‐scale invasion patterns allows managers to target invasion prone patches, potentially reducing management intensities. Furthermore, management effort may be optimised by spatially de‐coupling Betula seed from safe‐sites. This plan may adaptable to the management of other weeds and open‐land ecosystems. 相似文献
11.
Fire regimes in north-eastern Cambodian monsoonal forests, with a 9300-year sediment charcoal record 总被引:3,自引:0,他引:3
Andrew L. Maxwell 《Journal of Biogeography》2004,31(2):225-239
Aim To provide insights concerning changes in fire regime in north‐eastern Cambodia over the course of the Holocene, and discuss implications of these long‐term data for fire management in the present day. Location Southern Ratanakiri Province, north‐eastern Cambodia. The lake sites sampled here are embedded in a mosaic of mostly open, strongly deciduous dipterocarp forest, with patches of riparian, semi‐evergreen and evergreen forests. Methods Background information on the environmental and cultural setting comes from informal and semi‐structured interviews of local villagers to determine present‐day burning patterns and customs. Primary data come from analysis of changes in charcoal concentration within sediments from small, closed basin lakes. Charcoal data are compared with changes in pollen and sediment physical characteristics, and to present‐day local customs, to infer or speculate on changes in human use of fire. Results Interviews with local people reveal two general types of human‐induced fires, one type for swidden cultivation in denser forests, the other type for clearance of ground layer vegetation in more open forests. A 9300‐year sediment record of microscopic charcoal deposition shows strongest fire activity ending by 8000 years ago, and the remainder of the early Holocene reflecting a strong summer monsoon and low fire activity. Beginning c. 5500 years ago, forest disturbance and fire activity increased. A subtle change in the record at c. 3500 years ago and more marked change at c. 2500 years ago suggest that fire frequency, and maybe human control over fire, became more important during that period and continuing up to the present. Main conclusions With this type of empirical data from only one site, it is impossible to make accurate conclusions about long‐term human impacts from burning. However, this record does show that present‐day charcoal input from fire activity is among the lowest for the last 9300 years. Considered together with other changes in the record and with present‐day customs, there is a suggestion that anthropogenic fire is an adaptation to the monsoonal environment, and may be conservative of forest cover in open forest formations. This long‐term perspective on the role of indigenous land‐use customs in landscape evolution should be considered in forest management and biological conservation, as it differs significantly from the traditional rationale for policies of fire suppression in tropical forests. 相似文献
12.
The sediment stratigraphy of a medium-sized mixotrophic lake (Ruila) situated below the highest shoreline of the Baltic Ice
Lake in the West-Estonian Lowland is described. The lake is without natural inlets our outlets. The reconstruction of vegetation
and land-use history based on pollen data, combined with available archaeological data and detailed 14C dating allows us to give a provisional reconstruction of the temporal and spatial pattern of natural and human induced environmental
changes in north-west Estonia during the Holocene. Both radiocarbon dates derived from terrestrial macrofossil dating by accelerator
mass spectrometry (AMS) and conventional dating of bulk lake sediment are discussed. The isolation of the lake basin from
the Yoldia Sea took place ca. 9700 cal B. C. The Ancylus Lake transgression at ca. 8400 cal B. C. did not reach the basin,
but caused a ground water rise, seen in the sediment stratigraphy of the lake. The first signs of human impact on the pollen
record appear ca. 5400 cal B. C. (Late Mesolithic). The history of arable farming has been divided into three periods: 1)
introduction of crop cultivation and animal husbandry (1500 cal B. C. – A. D. 500); 2) establishment of animal husbandry A.
D. 500–1000) and 3) establishment of crop cultivation and intensive cattle breeding (A. D. 1000–today). Due to unfavourable
eda-phic conditions the introduction of arable farming was delayed for more than 1000 years compared with elsewhere on the
north coast of Esotnia, and intensity of land-use never reached the same proportion as in these areas.
Received August 15, 2001 / Accepted August 5, 2002
Correspondence to: Leili Saarse 相似文献
13.
We propose the integration of six data layers (topography, isohyets, soil potential, household localization, vegetation types and land lease titles) to assess the constraints facing food production in Vanuatu, Melanesia. All layers are digitalized allowing area computations of polygons associated with the various data sets. For each island, the following are computed: total area, good arable land area, coconut plantations, pastures/grasslands, area under land lease titles and average accessible good land per household. Although Vanuatu is often considered as not densely populated (19?hab/km2), results indicate great variation among islands. The average area of good land per household varies from 530?ha on the island of Tegua (North) to 0.5?ha on Futuna (South). Shifting cultivation does not appear to be a serious threat to the environment. The establishment of coconut plantations and permanent pastures represents the main cause of deforestation and contributes to increased pressure on land used for food production. The integration of layers of data is a powerful tool for improving environmental planning in an archipelago under growing human pressure and natural changes. 相似文献
14.
Silvoarable agroforestry (SAF) has recently been proposed as an alternative land-use system for Europe. Data on soil, climate, topography, and land cover were integrated in a geographic information system (GIS) to identify agroforestry target regions where (i) productive growth of trees (Juglans spp., Prunus avium, Populus spp., Pinus pinea, and Quercus ilex) in SAF systems could be expected and where (ii) SAF systems could potentially reduce the risk of soil erosion, nitrate leaching and increase landscape diversity.The analysis shows that the investigated tree species could grow productively in SAF systems on 56% of the arable land throughout Europe (potential productive tree growth area). 80% of the European arable land was classified as potential risk area for soil erosion, nitrate leaching, and/or landscape diversity. Overlaying potential productive tree growth areas with the arable land that was considered as environmental risk area yielded target regions. They were found to make up about 40% of the European arable land and thus SAF could contribute to soil protection on 4%, to mitigate nitrate leaching on 18% and to increase landscape diversity on 32% of European arable land.Although limited by constrained data availability, the study shows that SAF could be implemented in a productive way throughout Europe and that it could help resolve some of the major land-use problems. The environmental benefits could justify the support of SAF by subsidies. 相似文献
15.
《新西兰生态学杂志》2011,15(1):99-106
Replacing native forests and grasslands with plantations, pastures and crops has resulted in both contraction of ranges and exploitation of modified habitats by native species, and both general and restricted dispersal of introduced species of soil fauna. Contraction is shown by native earthworms, land snails, ring nematodes and various arthropods, while the areas with changed land use suggest certain native insects are more numerous than 150 years ago. Damage to pastures by grass grub and porina show clearly how native species can exploit modified habitats. Introduced Lumbricidae make a positive contribution to soil processes in pastures throughout New Zealand. The distribution of cyst nematodes reflects the distribution and intensity of cultivation of the hosts with which they arrived. Changes in soil structure, such as with the elimination or introduction of earthworms, can have marked effects on other soil structure, such as with the elimination or introduction of earthworms, can have marked effects on other soil animals. The faunal changes found are consistent with changes in land use; habitat protection for floristic and scenic reasons will help preserve both known and unknown elements of the soil fauna. 相似文献
16.
Christoph Schwörer Petra Kaltenrieder Lukas Glur Matthias Berlinger Julie Elbert Stephanie Frei Adrian Gilli Albert Hafner Flavio S. Anselmetti Martin Grosjean Willy Tinner 《Vegetation History and Archaeobotany》2014,23(5):479-496
Treelines are expected to rise to higher elevations with climate warming; the rate and extent however are still largely unknown. Here we present the first multi-proxy palaeoecological study from the treeline in the Northwestern Swiss Alps that covers the entire Holocene. We reconstructed climate, fire and vegetation dynamics at Iffigsee, an alpine lake at 2,065 m a.s.l., by using seismic sedimentary surveys, loss on ignition, visible spectrum reflectance spectroscopy, pollen, spore, macrofossil and charcoal analyses. Afforestation with Larix decidua and tree Betula (probably B. pendula) started at ~9,800 cal. b.p., more than 1,000 years later than at similar elevations in the Central and Southern Alps, indicating cooler temperatures and/or a high seasonality. Highest biomass production and forest position of ~2,100–2,300 m a.s.l. are inferred during the Holocene Thermal Maximum from 7,000 to 5,000 cal. b.p. With the onset of pastoralism and transhumance at 6,800–6,500 cal. b.p., human impact became an important factor in the vegetation dynamics at Iffigsee. This early evidence of pastoralism is documented by the presence of grazing indicators (pollen, spores), as well as a wealth of archaeological finds at the nearby mountain pass of Schnidejoch. Human and fire impact during the Neolithic and Bronze Ages led to the establishment of pastures and facilitated the expansion of Picea abies and Alnus viridis. We expect that in mountain areas with land abandonment, the treeline will react quickly to future climate warming by shifting to higher elevations, causing drastic changes in species distribution and composition as well as severe biodiversity losses. 相似文献
17.
Hussein M. Sulieman Manfred F. Buchroithner Muna M. Elhag 《African Journal of Ecology》2012,50(2):233-242
The vegetation cover in Gadarif Region, Sudan, underwent drastic changes within the last 60 years because of the combined effect of anthropogenic and climatic factors. As a consequence, a large number of plant species are threatened or even became extinct, and vast areas are now deforested. The purpose of this study is to use the local knowledge as a tool to identify and describe patterns of vegetation changes associated with the introduction of mechanized rain‐fed agriculture in the southern Gadarif Region. Data were collected by interviewing 10 key informants and 41 large‐scale farmers. The results provided rich ethnobotanical knowledge and a clear historical perspective of vegetation changes including plant species which have disappeared, decreased and increased in the area. The main factors leading to changes in plant species composition and abundance were vegetation clearance, charcoal and firewood production, wood cuttings, grazing and recently herbicides application. Respondents acknowledged that grazing, duration of abandonment, length of cultivation period, amount and variability of rainfall, fire events and weed composition are the major factors determining succession on fallow land. Farmers showed interest to preserve some multi‐purpose woody species (e.g. Acacia senegal, Balanites aegyptiaca) in their land. Such species should be given priority in rehabilitation activities. 相似文献
18.
Matteo Negro Achille Casale Luca Migliore Claudia Palestrini Antonio Rolando 《Biodiversity and Conservation》2007,16(13):3919-3932
We assessed the response of a guild of endemic medium and large-bodied carabid species to the local (fine-grained) habitat
heterogeneity induced by man. The study was conducted by means of trapping (without killing and preservative agents) and radio-tracking
methods (to collect data on the spatial ecology of the endangered species Carabus olympiae Sella). Habitat differentiation induced by man (a mosaic of beech forests, alpen rose shrubberies and pastures) affected
species richness and abundance of the guild, which were significantly higher in forests and/or shrubberies than in pastures.
Most species preferred forests and shrubberies, with the only exception of Carabus concolor Fabricius, which preferred open areas. Species distribution was also affected by stone density and cattle grazing intensity.
In particular, petrophilous species peaked on the roadside because of the high stone density there (stones amassed during
road construction), while species abundances significantly lowered in overgrazed pastures. The compactness of the paths made
by C. olympiae individuals (evaluated through a tortuosity index) was significantly higher in beech forests than in alpen rose shrubberies,
indicating movements in the latter habitat type were bound by the spatial distribution of shrubs, which imposes a limit on
path tortuosity. Our findings suggest that local ground beetle species diversity strongly depends on small-scale anthropogenic
variables (namely habitat type, stone density and grazing intensity), and that habitat modifications (namely from forest to
shrubbery) may significantly affect species movement patterns. General and local conservation management suggestions are given
in conformity with these results. 相似文献
19.
A.P. Donald 《Plant Ecology & Diversity》2013,6(4):281-289
Summary Pollen analytical data are presented from a site near Cupar, Fife. The stratigraphy and pollen spectra are used to infer the changing patterns of vegetation in the area during the Lateglacial and Postglacial periods. In the Lateglacial Interstadial the local development of Betula-Juniperus scrub was followed by a period of open habitat during the colder Loch Lomond Stadial. The early Postglacial forest was dominated by Corylus and Betula, although Ulmus was also a major woodland component before the arrival of Alnus. Following some initial deforestation due to anthropogenic activity, subsequent woodland clearance was almost total and open habitat communities dominated. 相似文献
20.
Ian A. Simpson W. Paul Adderley Garðar Guðmundsson Margrét Hallsdóttir Magnús Á. Sigurgeirsson Mjöll Snæsdóttir 《Human ecology: an interdisciplinary journal》2002,30(4):423-443
Early arable activity in Iceland, introduced in the late ninth century A.D., has been characterized as marginal and at a subsistence level, largely abandoned by the 1500s as a result of climatic deterioration. This view has been advanced without considering soils data, the medium in which crops are grown and in which evidence of early land management is retained. Soil thin section micromorphology together with soil total phosphorus values are used to assess land manuring and cultivation strategies at two sites in south-west Iceland, where place name and palynological evidence indicate that arable activity has taken place. Agro-ecosystem modeling, using the CENTURY model, is undertaken to predict grain yields at these sites, and to assess the significance of soil properties and soil management in determining yields. The results of these analyses demonstrate that manure application rates were low, and support the view that grain yields were at a subsistence level. The results also suggest soils, and the management of soils, rather than climate was the major limitation to arable production. Shortages of both available manure and labor are suggested as barriers to soils and grain productivity improvements in early Iceland. The paper highlights the need to include soils analyses in discussions of early agricultural economies. 相似文献