scholarly journals Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change?

2009 ◽  
Vol 5 (4) ◽  
pp. 647-659 ◽  
Author(s):  
A. Ngomanda ◽  
A. Chepstow-Lusty ◽  
M. Makaya ◽  
C. Favier ◽  
P. Schevin ◽  
...  
Keyword(s):  
Environmental History ◽  
Environmental Changes ◽  
Elaeis Guineensis ◽  
Coastal Region ◽  
Climatic Conditions ◽  
Secondary Forests ◽  
Progressive Decline ◽  
Equatorial Africa ◽  
History Of ◽  
Pollen Records

Abstract. Past vegetation and climate changes reconstructed using two pollen records from Lakes Maridor and Nguène, located in the coastal savannas and inland rainforest of Gabon, respectively, provide new insights into the environmental history of western equatorial African rainforests during the last 4500 cal yr BP. These pollen records indicate that the coastal savannas of western equatorial Africa did not exist during the mid-Holocene and instead the region was covered by evergreen rainforests. From ca. 4000 cal yr BP a progressive decline of inland evergreen rainforest, accompanied by the expansion of semi-deciduous rainforest, occurred synchronously with grassland colonisation in the coastal region of Gabon. The contraction of moist evergreen rainforest and the establishment of coastal savannas in Gabon suggest decreasing humidity from ca. 4000 cal yr BP. The marked reduction in evergreen rainforest and subsequent savanna expansion was followed from 2700 cal yr BP by the colonization of secondary forests dominated by the palm, Elaeis guineensis, and the shrub, Alchornea cordifolia (Euphorbiaceae). A return to wetter climatic conditions from about 1400 cal yr BP led to the renewed spread of evergreen rainforest inland, whereas a forest-savanna mosaic still persists in the coastal region. There is no evidence to suggest that the major environmental changes observed were driven by human impact.

scholarly journals Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change?

2009 ◽  
Vol 5 (1) ◽  
pp. 341-367 ◽  
Author(s):  
A. Ngomanda ◽  
A. Chepstow-Lusty ◽  
M. Makaya ◽  
C. Favier ◽  
P. Schevin ◽  
...  
Keyword(s):  
Environmental History ◽  
Late Holocene ◽  
Environmental Changes ◽  
Elaeis Guineensis ◽  
Coastal Region ◽  
Climatic Conditions ◽  
Rapid Decline ◽  
Pollen Record ◽  
Secondary Forests ◽  
Equatorial Africa

Abstract. Past vegetation and climate changes reconstructed using two pollen records from Lakes Maridor and Nguène, Gabon, provide new insights into the environmental history of western equatorial African rainforests during the last 4500 cal yr BP. The Lake Maridor pollen record indicates that the coastal savannas of western equatorial Africa did not exist during the mid-Holocene and instead the region was covered by evergreen rainforests. In the Lake Nguène pollen record, a rapid decline of hygrophilous evergreen rainforest occurred around 4000 cal yr BP, synchronously with grassland expansion around Lake Maridor. The establishment of coastal savannas in Gabon suggests decreasing humidity at the onset of the late Holocene. The marked reduction in evergreen rainforest and subsequent savanna expansion was associated with the colonization of secondary forests dominated by the palm, Elaeis guineensis, in the coastal region and the shrub, Alchornea cordifolia, further inland. A return to wetter climatic conditions from about 1400 cal yr BP led to the renewed spread of evergreen rainforest inland, whereas a forest-savanna mosaic still persists in the coastal region. There is no evidence to suggest that the major environmental changes observed are driven by human impact.

Late Quaternary Climate and Vegetation of the Sudanian Zone of Northeast Nigeria

2002 ◽  
Vol 58 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Ulrich Salzmann ◽  
Philipp Hoelzmann ◽  
Irena Morczinek
Keyword(s):  
Environmental History ◽  
Late Pleistocene ◽  
Late Quaternary ◽  
Climatic Conditions ◽  
Lake Levels ◽  
The Holocene ◽  
Quaternary Climate ◽  
History Of ◽  
Sudanian Zone ◽  
Humid Period

AbstractThe Lake Tilla crater lake in northeastern Nigeria (10°23′N, 12°08′E) provides a ca. 17,000 14C yr multiproxy record of the environmental history of a Sudanian savanna in West Africa. Evaluation of pollen, diatoms, and sedimentary geochemistry from cores suggests that dry climatic conditions prevailed throughout the late Pleistocene. Before the onset of the Holocene, the slow rise in lake levels was interrupted by a distinct dry event between ca. 10,900 and 10,500 14C yr B.P., which may coincide with the Younger Dryas episode. The onset of the Holocene is marked by an abrupt increase in lake levels and a subsequent spread of Guinean and Sudanian tree taxa into the open grass savanna that predominated throughout the Late Pleistocene. The dominance of the mountain olive Olea hochstetteri suggests cool climatic conditions prior to ca. 8600 14C yr B.P. The early to mid-Holocene humid period culminated between ca. 8500 and 7000 14C yr B.P. with the establishment of a dense Guinean savanna during high lake levels. Frequent fires were important in promoting the open character of the vegetation. The palynological and palaeolimnological data demonstrate that the humid period terminated after ca. 7000 14C yr B.P. in a gradual decline of the precipitation/evaporation ratio and was not interrupted by abrupt climatic events. The aridification trend intensified after ca. 3800 14C yr B.P. and continued until the present.

scholarly journals OSTRACODA FROM SUBSURFACE SEDIMENTS OF KARIMATA STRAIT AS INDICATOR OF ENVIRONMENTAL CHANGES

2016 ◽  
Vol 29 (1) ◽  
pp. 1
Author(s):  
Kresna Tri Dewi ◽  
Riza Rahardiawan
Keyword(s):  
Environmental History ◽  
Environmental Changes ◽  
Major Elements ◽  
Middle Part ◽  
Additional Information ◽  
Subsurface Sediments ◽  
History Of ◽  
Java Sea ◽  
Karimata Strait ◽  
Malacca Strait

Karimata Strait is a part of Sunda Shelf connected South China Sea with Malacca Strait, Indian Ocean and Java Sea. This shelf was a large Sunda Land that has been detected by many evidences as records of various paleo-environments. The purpose of this study is to recognize the characteristic community of ostracoda related to the environmental history of this shelf. Three selected cores sediments represented east (A), middle (B) and west (C) parts of Karimata Strait were used for Ostracoda based on standard method on micropaleontology. Additional method was applied of SEM-EDX analysis to abnormal specimens. The result shows that there are 43 species of ostracoda belonging to 34 genera identified in the study area. The highest number of ostracoda is found in Core B, in the middle part of the strait, and the lowest value belongs to the Core A that close to the land of Kalimantan. Several genera of Ostracoda were documented in all cores: Actinocythereis, Cytherella, Cytherelloidea, Keijia, Keijella, Hemicytheridea, Hemikrithe, Neocytheretta, Neomonoceratina, Loxoconcha, Pistocythereis, Stigmatocythere and Xestoleberis. Vertically, ostracoda are mostly found in the upper part of the cores and decrease or disappear in the lower part of Cores A and C where dominated by black organic materials. It may relate to a wide swampy area before the last sea level rise as part of the history of the SundaShelf about 15,000 years ago. Some major elements (C, CaO, Al2O4, FeO, SiO2, MgOdan SO3 covered or filled abnormal specimens that can provide additional information about environmental changes in the study area, such as Carbon may relate to charcoal from land of Kalimatan and Sumatera Keywords: Ostracoda, subsurface sediment, EDX, environmental changes, Karimata Strait Selat Karimata merupakan bagian dari Paparan Sunda menghubungkan Laut China Selatan dengan Selat Malaka, Samudera Hindia, dan Laut Jawa. Paparan ini merupakan sebuah Dataran Sunda yang luas yang terdeteksi dari bukti-bukti sebagai rekaman berbagai lingkungan purba.Tujuan dari studi ini adalah untuk mengetahui karakteristik komunitas ostracoda berkaitan dengan sejarah lingkungan paparan ini. Terpilih tiga sedimen pemercontoh inti mewakili bagian timur (A), tengah (B) dan barat (C) Selat Karimata digunakan untuk studi Ostracoda berdasarkan metoda standar pada mikropaleontologi. Metoda tambahan adalah aplikasi SEM-EDX terhadap spesimen abnormal. Hasil menunjukkan bahwa di daerah penelitian teridentifikasi 43 spesies ostracoda termasuk dalam 34 genera. Jumlah ostracoda tertinggi ditemukan di Core B dari bagian tengah selat dan terendah di Core A yang berdekatan dengan daratan Kalimantan. Beberapa genera ostracoda ditemukan di semua sampel: Actinocythereis, Cytherella, Cytherelloidea, Keijia, Keijella, Hemicytheridea, Hemikrithe, Neocytheretta, Neomonoceratina, Loxoconcha, Pistocythereis, Stigmatocythere dan Xestoleberis. Secara vertikal, ostracoda umumnya ditemukan di bagian atas dari core dan menurun atau menghilang di bagian bawah Core A dan C yang di dominasi oleh material organik berwarna hitam. Hal ini kemungkinan berkaitan dengan daerah rawa yang luas dan sebelum muka laut naik terakhir pada sejarah Paparan Sunda sekitar 15.000 tahun yang lalu. Beberapa zat kimia (C, CaO, Al2O3, FeO, SiO2, MgO dan SO3) menutupi atau mengisi spesimen abnormal dapat memberi informasi tambahan tentang perubahan lingkungan di daerah penelitian, seperti karbon mungkin berkaitan dengan arang dari daratan Kalimantan dan Sumatera. Kata kunci: Ostracoda, sedimen bawah dasar laut, EDX, perubahan lingkungan, Selat Karimat

Younger Dryas to mid-Holocene environmental history of the lowlands of NW Transylvania, Romania

2007 ◽  
Vol 68 (3) ◽  
pp. 364-378 ◽  
Author(s):  
Angelica Feurdean ◽  
Volker Mosbrugger ◽  
Bogdan P. Onac ◽  
Victor Polyak ◽  
Daniel Veres
Keyword(s):  
Environmental History ◽  
Environmental Changes ◽  
Younger Dryas ◽  
Total Carbon ◽  
Small Populations ◽  
Minor Constituent ◽  
Effective Moisture ◽  
Competition Effects ◽  
History Of ◽  
A Minor

AbstractPollen, micro-charcoal and total carbon analyses on sediments from the Turbuta palaeolake, in the Transylvanian Basin of NW Romania, reveal Younger Dryas to mid-Holocene environmental changes. The chronostratigraphy relies on AMS 14C measurements on organic matter and U/Th TIMS datings of snail shells. Results indicate the presence of Pinus and Betula open woodlands with small populations of Picea, Ulmus, Alnus and Salix before 12,000 cal yr BP. A fairly abrupt replacement of Pinus and Betula by Ulmus-dominated woodlands at ca. 11,900 cal. yr BP likely represents competition effects of vegetation driven by climate warming at the onset of the Holocene. By 11,000 cal yr BP, the woodlands were increasingly diverse and dense with the expansion of Quercus, Fraxinus and Tilia, the establishment of Corylus and the decline of upland herbaceous and shrubs taxa. The marked expansion of Quercus accompanied by Tilia between 10,500 and 8000 cal yr BP could be the result of low effective moisture associated with both low elevation of the site and with regional change towards a drier climate. At 10,000 cal yr BP, Corylus spread across the region, and by 8000 cal yr BP it replaced Quercus as a dominant forest constituent, with only little representation of Picea abies. Carpinus became established around 5500 cal yr BP, but it was only a minor constituent in local woodlands until ca. 5000 cal yr BP. Results from this study also indicate that the woodlands in the lowlands of Turbuta were never closed.

Lateglacial and early Flandrian environmental history of the Isle of Mull, Inner Hebrides, Scotland

1986 ◽  
Vol 77 (1) ◽  
pp. 1-20 ◽  
Author(s):  
J. J. Lowe ◽  
M. J. C. Walker
Keyword(s):  
Environmental History ◽  
Polar Front ◽  
Climatic Conditions ◽  
Plant Succession ◽  
Ice Cap ◽  
South Central ◽  
Tundra Vegetation ◽  
Loch Lomond ◽  
Thermal Maximum ◽  
History Of

ABSTRACTPollen-stratigraphic data, supported by lithological, geochemical and radiocarbon evidence are described from two Late Devensian Lateglacial sites on the Isle of Mull, Inner Hebrides, Scotland. The data suggest that, following the wastage of the Late Devensian ice sheet some time prior to 13,000 BP, an open grass- and sedge-dominated landscape was colonised first by juniper scrub and subsequently by Empetrum heaths. Tree birch development was limited principally, it would seem, by exposure to strong westerly winds, although some scattered birch woodland did become established in more sheltered localities. The thermal maximum of the Lateglacial Interstadial appears to have occurred from c. 13,000 to 12,000 BP after which climate began to deteriorate as the atmospheric Polar Front migrated southwards. The harsh climatic conditions of the Loch Lomond Stadial, the full effects of which were experienced after c. 10,700 BP, led to the break-up of the Interstadial vegetation cover, the development of an ice cap and several smaller cirque and valley glaciers in the hills of south-central Mull, and the establishment of a periglacial regime throughout the island. By c. 10,200 BP, however, climatic amelioration was underway once more, the Loch Lomond Advance glaciers had wasted completely, and a plant succession was initiated which led to the replacement of tundra vegetation communities by Empetrum heath, juniper scrub and eventually hazel-birch woodland within the space of c. 1500 years.

Reconstructing Climatic and Environmental Changes of the Past 1000 Years: A Reappraisal

2003 ◽  
Vol 14 (2-3) ◽  
pp. 233-296 ◽  
Author(s):  
Willie Soon ◽  
Sallie Baliunas ◽  
Craig Idso ◽  
Sherwood Idso ◽  
David R. Legates
Keyword(s):  
Environmental History ◽  
20Th Century ◽  
Environmental Changes ◽  
Ice Age ◽  
Local Climate ◽  
Proxy Records ◽  
Local Environments ◽  
Climate Indicators ◽  
Climatic Period ◽  
History Of

The 1000-year climatic and environmental history of the Earth contained in various proxy records is examined. As indicators, the proxies duly represent or record aspects of local climate. Questions on the relevance and validity of the locality paradigm for climatological research become sharper as studies of climatic changes on timescales of 50–100 years or longer are pursued. This is because thermal and dynamical constraints imposed by local geography become increasingly important as the air-sea-land interaction and coupling timescales increase. Because the nature of the various proxy climate indicators are so different, the results cannot be combined into a simple hemispheric or global quantitative composite. However, considered as an ensemble of individual observations, an assemblage of the local representations of climate establishes the reality of both the Little Ice Age and the Medieval Warm Period as climatic anomalies with world-wide imprints, extending earlier results by Bryson et al. (1963), Lamb (1965), and numerous other research efforts. Furthermore, these individual proxies are used to determine whether the 20th century is the warmest century of the 2nd Millennium at a variety of globally dispersed locations. Many records reveal that the 20th century is likely not the warmest nor a uniquely extreme climatic period of the last millennium, although it is clear that human activity has significantly impacted some local environments.

DOLI: TRANSLATING AN AFRICAN ENVIRONMENTAL HISTORY OF LOSS IN THE SANGHA RIVER BASIN OF EQUATORIAL AFRICA

2000 ◽  
Vol 41 (3) ◽  
pp. 373-394 ◽  
Author(s):  
TAMARA GILES-VERNICK
Keyword(s):  
Environmental History ◽  
Resource Use ◽  
Central African Republic ◽  
Environmental Knowledge ◽  
Environmental Interventions ◽  
Beliefs And Practices ◽  
The Past ◽  
Equatorial Africa ◽  
Complex Dimensions ◽  
History Of

This essay is about a conceptual category of historical and environmental knowledge and about how a particular group of Africans use that category to understand and debate change. It is, in effect, an exercise in translation. In the middle and upper Sangha basin forests of the Central African Republic (C.A.R.) and Cameroon, Mpiemu speakers have articulated a broad category, doli, through which they express, debate and make claims of truth about the past and present. Glossing doli as ‘history’ does little justice to the richly complex dimensions of this category, for doli encompasses a multitude of relationships to the past. It can refer to a distant unchanging past, as well as to the knowledge, beliefs and practices associated with that past. Mpiemu people hold up the knowledge, beliefs and practices as an idealized framework to guide their behavior toward one another and their uses of fields, forests, rivers and streams. But doli can also describe and frame the accumulated experiences – identifiable events, people and places – of elderly people. In all of these expressions about the past, Mpiemu use idioms linking persons and their environments, those of cords and vines and of mobility (wandering) and stasis (sitting), to articulate doli's central aim of ‘leaving a person behind’. Tracing doli's different meanings, genres and aims can illuminate how the category has changed over the twentieth century, how Mpiemu have interpreted environmental interventions in the Sangha basin, and why they have engaged in conflicts over their entitlement to valued forest resources. Hence, it offers insights into why people use natural resources as they do and provides an alternative to exclusively materialist explanations for conflicts over resource use.

A 14,000 year peatland record of environmental change in the southern Gutland region, Luxembourg

The Holocene ◽  
2021 ◽  
pp. 095968362199464
Author(s):  
Karsten Schittek ◽  
Lelaina Teichert ◽  
Katrin Geiger ◽  
Klaus-Holger Knorr ◽  
Simone Schneider
Keyword(s):  
Bronze Age ◽  
Environmental History ◽  
Middle Ages ◽  
Late Pleistocene ◽  
Vegetation History ◽  
Climatic Conditions ◽  
Peat Deposits ◽  
Organic Sediment ◽  
Species Abundances ◽  
History Of

A Late Pleistocene/Holocene paleoenvironmental record was obtained from the Rouer peatland (5°54′E, 49°45′N; 270 m a.s.l.), located in the Gutland area of southern Luxembourg. A total of six sediment samples were AMS radiocarbon-dated to obtain an age-depth model. XRF analyses and analyses of geochemical proxies of organic matter (TOC, TN, δ13C, δ15N) were conducted to identify major paleoenvironmental changes in the record. Pollen analysis reveals insights into the vegetation history throughout the last 14,000 cal. yr BP. The record offers unique insights into the evolution of local organic sediment/peat accumulation, as well as into the environmental history of the Gutland region and beyond. The accumulation of organic sediment and peat started at about 13,800 cal. yr BP before present. Until about 6000 cal. yr BP, periods of apparently stable climatic conditions had been interrupted repeatedly by pronounced episodes with increased input of minerogenic matter into the peat matrix (12,700–11,800 cal. yr BP; 11,500–11,300 cal. yr BP; 11,100–10,800 cal. yr BP; 9300 cal. yr BP; 8200 cal. yr BP), indicated by sudden increases of Ti/coh values. After 6000 cal. yr BP, environmental conditions stabilized. Between 4200 and 2800 cal. yr BP, during the Bronze Age, changes in the pollen spectrum indicate an increasing clearance of woodlands. Since the Roman period, an ongoing intensification of grassland farming and agriculture is evidenced. Lowest tree species abundances are witnessed during the Middle Ages. The Modern Era is characterized by enhanced sediment input due to soil erosion. In short, this record complements the Late Pleistocene/Holocene climatic history of the Gutland area and demonstrates that fen peat deposits can be valuable high-resolution paleoclimate archives.

scholarly journals Sâncraiu de Mureș (Marosszentkirály): medieval settlement network, Pauline monastery and its environment on the middle course of the Mureş river

2020 ◽  
Vol 71 (1) ◽  
pp. 177-198
Author(s):  
Elek Benkő ◽  
Pál Sümegi ◽  
Tünde Törőcsik ◽  
Elvira Bodor ◽  
Balázs Sümegi ◽  
...  
Keyword(s):  
Early Modern ◽  
Environmental History ◽  
Middle Ages ◽  
Environmental Changes ◽  
Early Modern Period ◽  
Economic Life ◽  
Multidisciplinary Research ◽  
Modern Period ◽  
History Of ◽  
Eastern Periphery

AbstractThe study aims to contribute to the medieval environmental history of the eastern periphery of the Transylvanian Plain (Câmpia Transilvaniei/Mezőség). With the help of archaeological and historical data and the multi-aspect analysis of undisturbed core sequences, the economic life of the Pauline Monastery founded in the 14th century near Sâncraiu de Mureş (Marosszentkirály) and the surrounding villages was investigated. The multidisciplinary research focuses on the paleochannels of the Mureş and the artificial watercourses (ditches) that branch off the river, and the mills built on them. The work also provides new data on the general environmental changes in the middle course of the Mureş river during the Middle Ages and the early modern period, which are largely due to the very intense human activity here.

Cotton and Salt: Swedish Colonial Aspirations and the Transformation of Saint Barthélemy in the Eighteenth Century

2020 ◽  
Vol 26 (2) ◽  
pp. 261-287
Author(s):  
Holger Weiss ◽  
Laura Hollsten ◽  
Stefan Norrgård
Keyword(s):  
Environmental History ◽  
Sugar Cane ◽  
Environmental Changes ◽  
Caribbean Region ◽  
Early Nineteenth Century ◽  
Scarce Resources ◽  
History Of ◽  
Environmental Histories ◽  
The Caribbean

The environmental history of the Caribbean has been strongly associated with the consequences of sugar cane agriculture and extreme weather phenomena. Consequently, other aspects of environmental change at play in the Caribbean region have remained less known. However, islands such as Anguilla, Barbuda, and Saint Barthélemy had no or very few sugar plantations. The fact that non-sugar producing islands had to find other ways of supporting themselves shaped their environmental history in ways that differed from that of the sugar islands. These alternative environmental histories deserve to be highlighted when presenting the historiography of the Caribbean. In this article, the island of Saint Barthélemy serves as a case study of an island where sugar cane agriculture was absent and tropical storms and hurricanes were of lesser consequence. In outlining the environmental history of Saint Barthélemy during the first decades of Swedish colonial rule, in the late eighteenth and early nineteenth century, the article shows that the Swedish takeover resulted in environmental changes. Sweden’s ambitions and expectations concerning the improvement of the island were initially high and much effort was put into the development of the economy. The rationale for the Swedish plans was to exploit the few and scarce resources of the island, but it was the harbour that became the most successful endeavour.

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