scholarly journals Environmental Reconstructions in the Upper Tana region, Kenya

2020 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
Lazarus Kinyua Ngari
Keyword(s):  
Environmental Change ◽  
Human Activities ◽  
Vegetation Change ◽  
Environmental Changes ◽  
Climatic Factors ◽  
Livestock Grazing ◽  
Plant Succession ◽  
Economic Activities ◽  
Agricultural Communities ◽  
The Past

This article sets out to unravel aspects of environmental changes in the Upper Tana during the second millennium AD. This aspect has not been adequately addressed in the Upper Tana. This makes it clear that a lacuna exists in the study of communities of the Upper Tana and the way they interact with their environment in the past and present times. The objective of this article is to evaluate the relationship between human activities and environmental change in the Upper Tana from AD 1000 to 1950. It is hypothesized that the advent of iron technology and its attendant economic activities led to the depletion of indigenous forests and the general environmental degradation. The article has employed archaeological, ethnographic, oral and historical methodologies to gather data on vegetation change in the Upper Tana and other related regions.  The article, argues that livestock grazing, iron smelting, slush and burn agriculture, and the clearing of forests for housing are key contributors to vegetation change in the Upper Tana.  Results from oral reconstruction of the past vegetation of the area, and using the plant succession theory, shows that the lowland area of the Upper Tana is actually savanna with scattered trees probably inhabited by grazers. It is posited that the above factors, together with persistent droughts have altered the vegetation cover of the area.  What we have today is colonization of less desirable stunted growth. The theory advanced here is that the vegetation change has been a result of human activities.  Overwhelmingly, results the study that the researcher carried out, showed that the causes of these changes have been socio-economically associated with the expansion of agricultural communities into the area; rather than through climatic factors. Colonisation and other forces of modernistion have also contributed to the underlying problem. The article concludes that anthropogenetic factors have greatly contributed to environmental change in the upper Tana. Certainly, environmental change is a global phenomenon that has elicited research interests due to its negative impacts on human population. It is recommended that knowledge of environmental change in the past should be used to extrapolate modern environmental challenges affecting African ecosystems.

Four Decades of Environmental Change and Their Influence upon Native Wildlife and Fish on the Mid-Columbia River, Washington, USA

1985 ◽  
Vol 12 (3) ◽  
pp. 241-248 ◽  
Author(s):  
William H. Rickard ◽  
Donald G. Watson
Keyword(s):  
Environmental Change ◽  
Agricultural Practices ◽  
Columbia River ◽  
Livestock Grazing ◽  
Irrigated Agriculture ◽  
Hanford Site ◽  
Bald Eagles ◽  
The Past ◽  
Riverine Habitats ◽  
Hanford Reach

The Hanford Reach of the Columbia River has experienced a great deal of human-imposed environmental change within the past 40 years, as has much of the adjacent land. The major disturbances have been from hydroelectric dams' construction and an intensive expansion of irrigated agriculture. A notable exception to the steady expansion of agriculture and dam-building has been the 1,400 km2 Hanford Site, which was established in 1943. Today, the Hanford Site consists mostly of undeveloped land that still supports native vegetation. It is free from agricultural practices, and has also been essentially free from livestock grazing and the shooting of animal wildlife. This conservative land-use has favoured populations of native wildlife that use the riverine habitats of the Hanford Reach of the Columbia River—e.g. Mule Deer, Canada Goose, and Great Blue Heron, are notable instances.The Hanford Reach supports the only mainstem Chinook Salmon spawning habitat on the Columbia River. This population is maintained by a combination of natural spawning and artificial propagation in concert with a regulated harvest of returning adults. Numbers of mainstem spawning Salmon have increased markedly in the past 10 years, and this has attracted increasing numbers of wintering Bald Eagles to the Hanford Reach.

scholarly journals Monitoring the Spatial and Temporal Variations in The Water Surface and Floating Algal Bloom Areas in Dongting Lake Using a Long-Term MODIS Image Time Series

2020 ◽  
Vol 12 (21) ◽  
pp. 3622
Author(s):  
Mengmeng Cao ◽  
Kebiao Mao ◽  
Xinyi Shen ◽  
Tongren Xu ◽  
Yibo Yan ◽  
...  
Keyword(s):  
Water Quality ◽  
Human Activities ◽  
Water Surface ◽  
Algal Bloom ◽  
Environmental Changes ◽  
Climatic Factors ◽  
Dongting Lake ◽  
Dynamic Learning ◽  
Traditional Methods

Significant water quality changes have been observed in the Dongting Lake region due to environmental changes and the strong influence of human activities. To protect and manage Dongting Lake, the long-term dynamics of the water surface and algal bloom areas were systematically analyzed and quantified for the first time based on 17 years of Moderate Resolution Imaging Spectroradiometer (MODIS) observations. The traditional methods (index-based threshold algorithms) were optimized by a dynamic learning neural network (DL-NN) to extract and identify the water surface area and algal bloom area while reducing the extraction complexity and improving the extraction accuracy. The extraction accuracy exceeded 94.5% for the water and algal bloom areas, and the analysis showed decreases in the algal bloom and water surface areas from 2001–2017. Additionally, the variations in the water surface and algal bloom areas are greatly affected by human activities and climatic factors. The results of these analyses can help us better monitor human contamination in Dongting Lake and take measures to control the water quality during certain periods, which is crucial for future management. Moreover, the traditional methods optimized by the DL-NN used in this study can be extended to other inland lakes to assess and monitor long-term temporal and spatial variations in algal bloom areas and can also be used to acquire baseline information for future assessments of the water quality of lakes.

scholarly journals Vegetation Degradation and Its Driving Factors in the Farming–Pastoral Ecotone over the Countries along Belt and Road Initiative

2019 ◽  
Vol 11 (6) ◽  
pp. 1590 ◽  
Author(s):  
Qionghuan Liu ◽  
Xiuhong Wang ◽  
Yili Zhang ◽  
Huamin Zhang ◽  
Lanhui Li
Keyword(s):  
Vegetation Change ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Growth Strategy ◽  
Livestock Grazing ◽  
Climatic Variables ◽  
Belt And Road Initiative ◽  
Vegetation Degradation ◽  
Belt And Road ◽  
Anthropogenic Contributions

To adhere to the green growth strategy, it is urgently needed to identify the vegetation degradation zone in the farming–pastoral ecotone (FPE) over the countries along the “Belt and Road Initiative (BRI)”. In this study, we monitored vegetation degradation and analyzed climatic factors and anthropogenic contributions on vegetation change in the FPE during 2000–2016 using the growing season annual accumulative normalized difference vegetation index (NDVIaccu) and climatic variables. The Theil-Sen’s trend results revealed that 74.11% of NDVIaccu in FPEs showed a significant increasing trend for the period 2000–2016, only 1.64% of NDVIaccu were significantly decreasing. However, we detected that 21.29% degradation of NDVIaccu had occurred based on enhanced Theil-Sen and Mann-Kendall (ETheil-Sen-MK) method. Spatial statistics for significant correlations between climatic variables and NDVIaccu showed that precipitation was positively correlated with NDVIaccu; yet, the relationship between NDVIaccu and temperature was more complex, which was closely related to the intensity of increasing in temperature. Importantly, this study found that anthropogenic contributions dominated the trends in NDVIaccu over the FPE. The findings suggested that agricultural activities play a mainly positive role in overall vegetation vigor. However, continually increasing disturbance by livestock grazing risks further vegetation degradation.

Small peatland with a big story: 600-year paleoecological and historical data from a kettle-hole peatland in Western Russia

The Holocene ◽  
2021 ◽  
pp. 095968362110332
Author(s):  
Agnieszka Mroczkowska ◽  
Piotr Kittel ◽  
Katarzyna Marcisz ◽  
Ekaterina Dolbunova ◽  
Emilie Gauthier ◽  
...  
Keyword(s):  
Human Impact ◽  
Human Activities ◽  
Environmental Changes ◽  
Climatic Variability ◽  
Testate Amoebae ◽  
The Past ◽  
Kettle Hole ◽  
Rapid Changes ◽  
History Of ◽  
Physical And Chemical

Peatlands are important records of past environmental changes. Based on a multiproxy analysis, the main factors influencing the evolution of a peatland can be divided into autogenic and allogenic. Among the important allogenic factors, apart from climate change, are deforestation and drainage, which are directly associated with human impact. Numerous consequences arise from these processes, the most important of which are physical and chemical denudation in the catchment and the related hydrological disturbances in the catchment and peatland. The present study determined how human activities and the past climatic variability mutually influenced the development of a small peatland ecosystem. The main goals of the study were: (1) to trace the local changes of the peatland history over the past 600 years, (2) to investigate their relationship with changes in regional hydroclimate patterns, and (3) to estimate the sensitivity of a small peatland to natural and human impact. Our reconstructions were based on a multiproxy analysis, including the analysis of pollen, macrofossils, Chironomidae, Cladocera, and testate amoebae. Our results showed that, depending on the changes in water level, the history of peatland can be divided into three phases as follows: 1/the phase of stable natural conditions, 2/phase of weak changes, and 3/phase of significant changes in the catchment. Additionally, to better understand the importance of the size of catchment and the size of the depositional basin in the evolution of the studied peatland ecosystem, we compared data from two peatlands – large and small – located close to each other. The results of our study indicated that “size matters,” and that larger peatlands are much more resilient and resistant to rapid changes occurring in the direct catchment due to human activities, whereas small peatlands are more sensitive and perfect as archives of environmental changes.

scholarly journals Four millennia of vegetation and environmental history above the Hyrcanian forest, northern Iran

2020 ◽  
Author(s):  
Leila Homami Totmaj ◽  
Elias Ramezani ◽  
Kammaledin Alizadeh ◽  
Hermann Behling
Keyword(s):  
Environmental History ◽  
Human Activities ◽  
Environmental Changes ◽  
Anthropogenic Activities ◽  
Plantago Lanceolata ◽  
Livestock Grazing ◽  
Forest Recovery ◽  
Hyrcanian Forest ◽  
Moisture Index ◽  
Northern Iran

AbstractPast vegetation, fire, and climate dynamics, as well as human impact, have been reconstructed for the first time in the highlands of the Gilan province in the Alborz mountains (above the Hyrcanian forest) for the last 4,300 cal yrs bp. Multi-proxy analysis, including pollen, spores, non-pollen palynomorphs, charcoal, and geochemical analysis, has been applied to investigate the environmental changes at 2,280 m a.s.l., above the Hyrcanian forest. Dominant steppe vegetation occurred in the study area throughout the recorded period. The formation of the studied mire deposits, as well as vegetation composition, suggest a change to wetter climatic conditions after 4,300 until 1,700 cal yrs bp. Fires were frequent, which may imply long-lasting anthropogenic activities in the area. Less vegetation cover with a marked decrease of the Moisture Index (MI) suggests drier conditions between 1,700 and 1,000 cal yrs bp. A high proportion of Cichorioideae and Amaranthaceae, as well as the reduction of trees, in particular Fagus and Quercus, at lower elevations, indicate human activities such as intense livestock grazing and deforestation. Soil erosion as the result of less vegetation due to dry conditions and/or human activities can be reconstructed from a marked increase of Glomus spores and high values of K and Ti. Since 1,000 cal yrs bp, the increasing MI, as well as the rise of Poaceae and Cyperaceae together with forest recovery, suggest a change to wetter conditions. The occurrence of still frequent Cichorioideae and Plantago lanceolata along with Sordaria reflect continued intense grazing of livestock by humans.

scholarly journals Analysis on vegetation cover changes and the driving factors in the mid-lower reaches of Hanjiang River Basin between 2001 and 2015

2021 ◽  
Vol 13 (1) ◽  
pp. 675-689
Author(s):  
Yunjun Zhan ◽  
Jiemeng Fan ◽  
Tingting Meng ◽  
Zhongwu Li ◽  
Yan Yan ◽  
...  
Keyword(s):  
River Basin ◽  
Human Activities ◽  
Vegetation Cover ◽  
Vegetation Change ◽  
Climatic Factors ◽  
Driving Factors ◽  
Jianghan Plain ◽  
Hanjiang River ◽  
The Impact ◽  
Positive Effect

Abstract The mid-lower reaches of the Hanjiang River Basin, located in the core of economic development in Hubei Province, is an integral part of the Yangtze River Economic Belt. In recent years, the watershed ecosystem has become more sensitive to climate changes and human activities, thus affecting the regional vegetation cover. To maintain a stable watershed ecosystem, it is critical to analyze and evaluate the vegetation change and its response to temperature, precipitation, and human activities in this region. This study, based on the trend analysis, partial correlation analysis, and residual analysis, evaluated the change characteristics of vegetation cover as well as the corresponding driving factors in the basin from 2001 to 2015. The results showed that (1) the overall spatial pattern of vegetation cover in the study area was “high in the west and north, lower on both sides of Hanjiang River, and lowest in the center and southeast,” and the pattern changed parabolically with the increasing elevation. (2) Over the 15 years, vegetation cover in the basin showed an increasing trend, and the increased and decreased areas were 90.72 and 9.23%, respectively. (3) The response of vegetation cover to climatic factors varies greatly depending on the increasing elevation. That is, the lag effect under the impact of temperature disappeared gradually, while it became more evident under the impact of precipitation. (4) On the whole, human activities had a positive effect on the regional vegetation cover. The negative effect in the areas around the Nanyang Basin and the positive effect in most parts of the Jianghan Plain were gradually decreased.

scholarly journals Christian Theodor Vaupell, a Danish 19th century naturalist and a pioneering developer of the Quaternary geoscience

2012 ◽  
Vol 3 (2) ◽  
pp. 143-150 ◽  
Author(s):  
J. K. Nielsen ◽  
S. Helama
Keyword(s):  
Vegetation Change ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Vegetative Reproduction ◽  
Scientific Work ◽  
Growth Patterns ◽  
Plant Succession ◽  
General Reference ◽  
North West

Abstract. Christian Theodor Vaupell (1821–1862) was a Danish scholar with pioneering investigations particularly on the late Quaternary development of bog forests, but also microscopy of plant anatomy and vegetative reproduction. His studies contributed to the early scientific thinking of the Quaternary environmental changes. Before his academic efforts, he had already survived the war between Prussia and Denmark albeit he became severely wounded and his left arm was amputated. The drama of his academic efforts, on the other hand, lies in the more or less suspicious dispute of his first doctoral thesis and his dismissal from the academic world during the following years. At the same time, he earned praise for his first thesis (never accepted as thesis but published as a regular book) from abroad; he was also able to attract private foundations for financial support of his scientific work. Following the enthusiasm of his time, Vaupell became attracted to the pine megafossils known to have been preserved in the bogs in north-west Europe. The megafossils led him to study not only the life systems of the ancient and modern bog forests but also their associations with Earth processes. As an interesting detail of his research, Vaupell made compound interpretations on the occurrence of megafossil stumps and their tree-ring growth patterns. In the course of the 20th century, Vaupell's studies have been cited as a general reference of post-glacial vegetation change and plant succession rather than clearly pioneering investigations of palaeoecology, an angle that we would like put into a contrasting perspective. To do so, we provide a brief portrait of Christian Vaupell and his research career. In conclusion, we wish to emphasize the comprehensiveness of Vaupell's views on the late Quaternary vegetation changes and the role of plant succession in that development.

scholarly journals Using Budyko-Type Equations for Separating the Impacts of Climate and Vegetation Change on Runoff in the Source Area of the Yellow River

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3418
Author(s):  
Dan Yan ◽  
Zhizhu Lai ◽  
Guangxing Ji
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Vegetation Change ◽  
Yellow River ◽  
Climatic Factors ◽  
Source Area ◽  
The Yellow River ◽  
Vegetation Changes ◽  
Potential Evaporation ◽  
Runoff Change

Assessing the contribution rates of climate change and human activities to the runoff change in the source area of the Yellow River can provide support for water management in the Yellow River Basin. This paper firstly uses a multiple linear regression method to evaluate the contribution rates of climate change and human activities to the vegetation change in the source area of the Yellow River. Next, the paper uses the Budyko hypothesis method to calculate the contribution rates of climatic factors (including precipitation, potential evaporation, and subsequent vegetation changes) and vegetation changes caused by human activities to the runoff change of the Tangnaihai Hydrometric Station. The results showed that: (1) the annual runoff and precipitation in the source area of the Yellow River have a downward trend, while the annual potential evaporation and NDVI (Normalized Difference Vegetation Index) show an increasing trend; (2) The contribution rates of climate change and human activities to the vegetation change in the source area of the Yellow River is 62.79% and 37.21%, respectively; (3) The runoff change became more and more sensitive to changes in climate and underlying surface characteristic parameters; (4) The contribution rates of climatic factors (including precipitation, potential evaporation, and subsequent vegetation changes) and vegetation changes caused by human activities to the runoff change at Tangnaihai Hydrological Station are 75.33% and 24.67%, respectively; (5) The impact of precipitation on runoff reduction is more substantial than that of potential evaporation.

Late-Holocene environmental change on the Nullarbor Plain, southwest Australia, based on speleothem pollen records

The Holocene ◽  
2020 ◽  
Vol 30 (5) ◽  
pp. 672-681
Author(s):  
Kia A Matley ◽  
JM Kale Sniderman ◽  
Andrew N Drinnan ◽  
John C Hellstrom
Keyword(s):  
Environmental Change ◽  
Vegetation Change ◽  
Environmental Changes ◽  
Species Abundance ◽  
Lacustrine Sediments ◽  
Southern Annular Mode ◽  
Fossil Pollen ◽  
Fire Event ◽  
History Of Vegetation ◽  
European Colonization

Fossil pollen from two stalagmites is examined to reconstruct a c. 2400-year history of vegetation change on the Nullarbor Plain. Environmental changes are reflected by variation in chenopod species abundance, and by a peak in woody taxa between 1000 and 800 years ago which is interpreted as evidence of increased moisture conditions associated with a positive phase of the Southern Annular Mode. While no strong palynological signal is observed at the time of European colonization of Australia, a significant change occurs in the past 40 years, which is interpreted as a vegetation response to a recorded fire event. As speleothems (secondary cave carbonates including stalagmites, stalactites and flowstones) rarely contain enough fossil pollen for analysis, the taphonomic biases of speleothem archives remain poorly understood. This study, as well as being a high-resolution record of environmental change, presents an opportunity to examine these taphonomic filters. The record is shown to be sensitive to episodic deposition of presumably insect-borne pollen, but overall appears to provide a faithful representation of local and regional vegetation change. There is a need for greater research into taphonomic processes, if speleothem palynology is to be developed as a viable alternative to lacustrine sediments in the investigation of past environmental change.

scholarly journals How Environmental Change Relates to the Development of Adaptation Strategies and Migration Aspirations

2021 ◽  
pp. 105-123
Author(s):  
Lore Van Praag ◽  
Loubna Ou-Salah ◽  
Elodie Hut ◽  
Caroline Zickgraf
Keyword(s):  
Climate Change ◽  
Environmental Change ◽  
Environmental Changes ◽  
Active Role ◽  
Adaptation Strategy ◽  
Agricultural Activities ◽  
Economic Activities ◽  
Intergovernmental Panel ◽  
Environmental Migration ◽  
And Migration

AbstractThe focus on perceived environmental changes and risks is a necessary precondition before people’s vulnerabilities and abilities to migrate can be taken into account (Adam 2005). This approach contrasts with previous research on environmental migration that has mainly focused on the vulnerabilities of people towards environmental changes. This vulnerability approach is, for instance, widely used in reports of the Intergovernmental Panel on Climate Change (IPCC 2014) and refers to the potential loss or harm one encounters or could encounter when facing environmental changes. This vulnerability is assumed to depend on the nature of the physical risks one could be exposed to and inherent sensitivity one has. The latter refers, for instance, to the type of economic activities of a community. For example, communities that rely heavily on agricultural activities are more sensitive to water scarcity and suffer more from drought, than other communities. It is within this framework that migration is often seen as a potential adaptation strategy to deal with environmental changes (Smit and Wandel 2006; Gemenne 2010). However, this framework hardly considers people’s own perceived vulnerabilities or risks or resilience towards environmental change. Hence, this vulnerability approach diminishes the agency of the actors involved and their active role in the development of migration aspirations and trajectories related to environmental changes and risks. Furthermore, as already stated by McLeman et al. (2016), the use of this framework of adaptation and the focus on the use of vulnerability may not encompass all drivers of environmental migration. This could certainly apply to the Moroccan context in which environmental changes mostly occur gradually and are to a lesser extent immediately visible to the human eye.

Sign in / Sign up

Export Citation Format

Share Document