scholarly journals Quantitative reconstruction of Holocene vegetation cover in Flanders, Belgium - a study based on pollen-records from alluvial floodplains

Author(s):  
Renske Hoevers ◽  
Nils Broothaerts ◽  
Gert Verstraeten

<p>Rivers and alluvial floodplains are dynamic environments facing natural and anthropogenic impacts. A thorough knowledge of the functioning of alluvial floodplains and their sensitivity to changes in internal and external driving forces is required for sustainable management of these ecosystems.</p><p>During the Early and Middle Holocene, most floodplains in northern and central Belgium were stable environments with limited floodplain aggradation resulting in the formation of peat. During these times, floodplains consisted mainly of large marshes where peat accumulated and river channels were absent or small. During the Late Holocene, these environments changed completely towards single channel meandering rivers with overbank deposits, impeding peat accumulation, largely as a result of increasing anthropogenic impact. However, this evolution in floodplain geoecology is diachronous as some river valleys transform a few thousand years before others.</p><p>Previous research already showed that river systems respond non-linearly to changes in land-use and land-cover in their catchments, as land-use intensity and slope-channel coupling need to cross a certain threshold to result in significant change. Hence, the differences in timing of floodplain response can to some extent be related to different land-use trajectories in the river catchments. Based on previous qualitative and semi-quantitative research the exact land-cover threshold, i.e. the land-use intensity required to result in transformation of the fluvial system, as well as the timing at which this threshold is crossed, could not be detected. Hence, a quantitative assessment of the resilience of floodplain environments to regional land-use changes is needed. A successful pilot REVEALS-based reconstruction of the Dijle catchment, showed a decrease in forest cover from the Bronze Age onwards, accompanied by an increase in the proportion of cereals.</p><p>In this study, we constructed a database of pollen-records collected in the eastern part of Flanders, mainly retrieved from river floodplains, as deposits from large lakes are not available in the area. We selected sites with varying soil properties, topographies, and histories of human impact in their catchments, to uncover regional differences in land-cover evolution through the application of the REVEALS model. To assess the applicability of this model to alluvial deposits, modern pollen data will be included and outcomes will be compared to modern vegetation maps. In addition, vegetation reconstructions will be compared with historical maps (available from 1778 AD onwards).</p><p>Results will help to answer questions regarding the sensitivity of Flanders to (future) environmental changes. Our study contributes to the understanding of Holocene land-cover change and its drivers, by providing quantitative vegetation cover reconstructions for Belgium that are currently lacking in the European REVEALS reconstructions. Moreover, it extends the application of the REVEALS model to pollen-records retrieved from alluvial deposits.</p>

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110261
Author(s):  
Hamza Islam ◽  
Habibuulah Abbasi ◽  
Ahmed Karam ◽  
Ali Hassan Chughtai ◽  
Mansoor Ahmed Jiskani

In this study, the Land Use/Land Cover (LULC) change has been observed in wetlands comprises of Manchar Lake, Keenjhar Lake, and Chotiari Reservoir in Pakistan over the last four decades from 1972 to 2020. Each wetland has been categorized into four LULC classes; water, natural vegetation, agriculture land, and dry land. Multitemporal Landsat satellite data including; Multi-Spectral Scanner (MSS), Thematic Mapper (TM), and Operational Land Imager (OLI) images were used for LULC changes evaluation. The Supervised Maximum-likelihood classifier method is used to acquire satellite imagery for detecting the LULC changes during the whole study period. Soil adjusted vegetation index technique (SAVI) was also used to reduce the effects of soil brightness values for estimating the actual vegetation cover of each study site. Results have shown the significant impact of human activities on freshwater resources by changing the natural ecosystem of wetlands. Change detection analysis showed that the impacts on the land cover affect the landscape of the study area by about 40% from 1972 to 2020. The vegetation cover of Manchar Lake and Keenjhar Lake has been decreased by 6,337.17 and 558.18 ha, respectively. SAVI analysis showed that soil profile is continuously degrading which vigorously affects vegetation cover within the study area. The overall classification accuracy and Kappa statistics showed an accuracy of >90% for all LULC mapping studies. This work demonstrates the LULC changes as a critical monitoring basis for ongoing analyses of changes in land management to enable decision-makers to establish strategies for effectively using land resources.


2021 ◽  
pp. 57-61
Author(s):  
Arunima Dasgupta

Given that urbanization is considered as one of the most signicant anthropogenic alteration of the overall environment, the present study attempts to understand spatial-temporal characteristics of urban population growth and its implications on land-use as well as understanding their relationship with environmental degradation with special focus on the Kolkata, the capital city of West Bengal. Urbanization is one of the major driving forces behind the development of today's land-use and land cover system. A large number of contemporary urbanization has been characterized as urban sprawl namely in an extensive form of land-use for urban uses that have environmentally detrimental effects. There are indications of Urban sprawl and city expansion in our Study Area of Kolkata indicating expansion of settlements and built-up area and thus causing environmental degradation in the city area. The process of urbanization always had signicant implications that can affect cumulative changes in demographic characteristics and/or transformation of the physical environment; unplanned, unsystematic and rapid urbanization can cause intense impacts on various environmental aspects, specically on land and air and water. A thorough understanding of the dynamic relationship between urbanization and its generated land-cover changes thus becomes completely essential for managing environmental changes and enabling sustainability of the environment and its resources.


2019 ◽  
Vol 8 (2) ◽  
pp. 118-131 ◽  
Author(s):  
T. V. Ramachandra ◽  
Bharath Setturu

The ecosystem of health and natural resource management is influenced by the social, political, economic system and institutional framework in a region. Rapid economic growth in Bangalore and its environs in recent decades has resulted in environmental changes in Bannerghatta National Park (BNP) and its buffer (of 5 km). Land use land cover (LULC) change analysis with a modelling technique such as cellular automata (CA)-Markov was used for quantitatively exploring forest cover transitions. The analysis of LULC dynamics has revealed loss of vegetation cover from 85.78 per cent to 66.37 per cent (1973–2015) and severe environmental stress. The region has lost moist deciduous cover, from 26.1 per cent to 13.8 per cent, and witnessed an increase in horticulture, from 8.5 per cent to 11 per cent (1973–2015). The visualization of likely land use in 2027 indicates the loss of forest cover from 41.38 per cent to 35.59 per cent with an increase in urban area from 4.49 per cent to 9.62 per cent (with new residential and commercial layouts in the buffer zone of BNP in violation of the eco-sensitive zone norms as per Section 5(1) of Environment Protection Act 1986). The study provides insights for developing an appropriate planning framework towards conservation and the sustainable management of ecologically sensitive national parks.


2019 ◽  
Vol 12 (1) ◽  
pp. 179-193 ◽  
Author(s):  
Chantelle Burton ◽  
Richard Betts ◽  
Manoel Cardoso ◽  
Ted R. Feldpausch ◽  
Anna Harper ◽  
...  

Abstract. Disturbance of vegetation is a critical component of land cover, but is generally poorly constrained in land surface and carbon cycle models. In particular, land-use change and fire can be treated as large-scale disturbances without full representation of their underlying complexities and interactions. Here we describe developments to the land surface model JULES (Joint UK Land Environment Simulator) to represent land-use change and fire as distinct processes which interact with simulated vegetation dynamics. We couple the fire model INFERNO (INteractive Fire and Emission algoRithm for Natural envirOnments) to dynamic vegetation within JULES and use the HYDE (History Database of the Global Environment) land cover dataset to analyse the impact of land-use change on the simulation of present day vegetation. We evaluate the inclusion of land use and fire disturbance against standard benchmarks. Using the Manhattan metric, results show improved simulation of vegetation cover across all observed datasets. Overall, disturbance improves the simulation of vegetation cover by 35 % compared to vegetation continuous field (VCF) observations from MODIS and 13 % compared to the Climate Change Initiative (CCI) from the ESA. Biases in grass extent are reduced from −66 % to 13 %. Total woody cover improves by 55 % compared to VCF and 20 % compared to CCI from a reduction in forest extent in the tropics, although simulated tree cover is now too sparse in some areas. Explicitly modelling fire and land use generally decreases tree and shrub cover and increases grasses. The results show that the disturbances provide important contributions to the realistic modelling of vegetation on a global scale, although in some areas fire and land use together result in too much disturbance. This work provides a substantial contribution towards representing the full complexity and interactions between land-use change and fire that could be used in Earth system models.


Land ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 152 ◽  
Author(s):  
Henry Schubert ◽  
Andrés Caballero Calvo ◽  
Markus Rauchecker ◽  
Oscar Rojas-Zamora ◽  
Grischa Brokamp ◽  
...  

Barranquilla is known as a dynamically growing city in the Colombian Caribbean. Urbanisation induces land use and land cover (LULC) changes in the city and its hinterland affecting the region’s climate and biodiversity. This paper aims to identify the trends of land use and land cover changes in the hinterland of Barranquilla corresponding to 13 municipalities in the north of the Department Atlántico. Landsat TM/ETM/OLI imagery from 1985 to 2017 was used to map and analyse the spatio-temporal development of land use and land cover changes. During the investigation period, the settlement areas grew by approximately 50% (from 103.3 to 153.6 km2), while areas with woody vegetation cover experienced dynamic changes and increased in size since 2001. Peri-urban and rural areas were characterized by highly dynamic changes, particularly regarding clearing and recovery of vegetated areas. Regression analyses were performed to identify the impact factors of detected vegetation cover changes. Computed logistic regression models included 20 independent variables, such as relief, climate, soil, proximity characteristics and socio-economic data. The results of this study may act as a basis to enable researchers and decision-makers to focus on the most important signals of systematic landscape transformations and on the conservation of ecosystems and the services they provide.


Ever since the advent of modern geo information systems, tracking environmental changes due to natural and/or manmade causes with the aid of remote sensing applications has been an indispensable tool in numerous fields of geography, most of the earth science disciplines, defence, intelligence, commerce, economics and administrative planning. One among these applications is the construction of land use and land cover maps through image classification process. Land Use / Land Cover (LULC) information is a crucial input in designing efficient strategies for managing natural resources and monitoring environmental changes from time to time. The present study aims to know the extent of land cover and its usage in Davangere region of Karnataka, India. In this study, satellite image of Davangere during October-November 2018 was used for LULC supervised classification with the help of remote sensing tools like QGIS and Google Earth Engine. Six LULC classes were decided to locate on the map and the accuracy assessment was done using theoretical error matrix and Kappa coefficient. The key findings include LULC under Water bodies (8%), Built up Area (15.1%), Vegetation (9%), Horticulture (20.8%), Agriculture (39.3%) and Others (7%) with overall accuracy of 94.8% and Kappa coefficient of 0.866 indicating almost accurate goodness of classification


Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1037
Author(s):  
Mohamed Ali Mohamed

Monitoring the impact of changes in land use/land cover (LULC) and land surface temperature (LST) is of great importance in environmental and urban studies. In this context, this study aimed to analyze the dynamics of LULC and its impact on the spatiotemporal variation of the LST in the two largest urban cities in Syria, Damascus, and Aleppo. To achieve this, LULC changes, normalized difference vegetation index (NDVI), and LST were calculated from multi-temporal Landsat data for the period 2010 to 2018. The study revealed significant changes in LULC, which were represented by a decrease in agricultural land and green areas and an increase in bare areas in both cities. In addition, built-up areas decreased in Aleppo and increased in Damascus during the study period. The temporal and spatial variation of the LST and its distribution pattern was closely related to the effect of changes in LULC as well as to land use conditions in each city. This effect was greater in Aleppo than in Damascus, where Aleppo recorded a higher increase in the mean LST, by about 2 °C, than in Damascus, where it was associated with greater degradation and loss of vegetation cover. In general, there was an increasing trend in the minimum and maximum LST as well as an increasing trend in the mean LST in both cities. The negative linear relationship between LST and NDVI confirms that vegetation cover can help reduce LST in both cities. This study can draw the attention of relevant departments to pay more attention to mitigating the negative impact of LULC changes in order to limit the increase in LST.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Kimberly M. Fornace ◽  
Adriana V. Diaz ◽  
Jo Lines ◽  
Chris J. Drakeley

AbstractLand use and land cover changes, such as deforestation, agricultural expansion and urbanization, are one of the largest anthropogenic environmental changes globally. Recent initiatives to evaluate the feasibility of malaria eradication have highlighted impacts of landscape changes on malaria transmission and the potential of these changes to undermine malaria control and elimination efforts. Multisectoral approaches are needed to detect and minimize negative impacts of land use and land cover changes on malaria transmission while supporting development aiding malaria control, elimination and ultimately eradication. Pathways through which land use and land cover changes disrupt social and ecological systems to increase or decrease malaria risks are outlined, identifying priorities and opportunities for a global malaria eradication campaign. The impacts of land use and land cover changes on malaria transmission are complex and highly context-specific, with effects changing over time and space. Landscape changes are only one element of a complex development process with wider economic and social dimensions affecting human health and wellbeing. While deforestation and other landscape changes threaten to undermine malaria control efforts and have driven the emergence of zoonotic malaria, most of the malaria elimination successes have been underpinned by agricultural development and land management. Malaria eradication is not feasible without addressing these changing risks while, conversely, consideration of malaria impacts in land management decisions has the potential to significantly accelerate progress towards eradication. Multisectoral cooperation and approaches to linking malaria control and environmental science, such as conducting locally relevant ecological monitoring, integrating landscape data into malaria surveillance systems and designing environmental management strategies to reduce malaria burdens, are essential to achieve malaria eradication.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Duong Cao Phan ◽  
Ta Hoang Trung ◽  
Van Thinh Truong ◽  
Taiga Sasagawa ◽  
Thuy Phuong Thi Vu ◽  
...  

AbstractExtensive studies have highlighted a need for frequently consistent land cover information for interdisciplinary studies. This paper proposes a comprehensive framework for the automatic production of the first Vietnam-wide annual land use/land cover (LULC) data sets (VLUCDs) from 1990 to 2020, using available remotely sensed and inventory data. Classification accuracies ranged from 85.7 ± 1.3 to 92.0 ± 1.2% with the primary dominant LULC and 77.6 ± 1.2% to 84.7 ± 1.1% with the secondary dominant LULC. This confirmed the potential of the proposed framework for systematically long-term monitoring LULC in Vietnam. Results reveal that despite slight recoveries in 2000 and 2010, the net loss of forests (19,940 km2) mainly transformed to croplands over 30 years. Meanwhile, productive croplands were converted to urban areas, which increased approximately ten times. A threefold increase in aquaculture was a major driver of the wetland loss (1914 km2). The spatial–temporal changes varied, but the most dynamic regions were the western north, the southern centre, and the south. These findings can provide evidence-based information on formulating and implementing coherent land management policies. The explicitly spatio-temporal VLUCDs can be benchmarks for global LULC validation, and utilized for a variety of applications in the research of environmental changes towards the Sustainable Development Goals.


Author(s):  
Cecilie S. Svenningsen ◽  
Diana E. Bowler ◽  
Susanne Hecker ◽  
Jesper Bladt ◽  
Volker Grescho ◽  
...  

AbstractRecent studies report declines in biomass, abundance and diversity of terrestrial insect groups. While anthropogenic land use is one likely contributor to this decline, studies assessing land cover as a driver of insect dynamics are rare and mostly restricted in spatial scale and types of land cover. In this study, we used rooftop-mounted car nets in a citizen science project (‘InsectMobile’) to allow for large-scale geographic sampling of flying insects across Denmark and parts of Germany. Citizen scientists sampled insects along 278 10 km routes in urban, farmland and semi-natural (grassland, wetland and forest) landscapes in the summer of 2018. We assessed the importance of local to landscape-scale effects and land use intensity by relating insect biomass to land cover in buffers of 50, 250, 500 and 1000 m along the routes. We found a negative association of urban cover and a positive association of farmland on insect biomass at a landscape-scale (1000 m buffer) in both countries. In Denmark, we also found positive effects of all semi-natural land covers, i.e. grassland (largest at the landscape-scale, 1000 m), forests (largest at intermediate scales, 250 m), and wetlands (largest at the local-scale, 50 m). The negative association of insect biomass with urban land cover and positive association with farmland were not clearly modified by any variable associated with land use intensity. Our results show that land cover has an impact on flying insect biomass with the magnitude of this effect varying across spatial scales. Since we consistently found negative effects of urban land cover, our findings highlight the need for the conservation of semi-natural areas, such as wetlands, grasslands and forests, in Europe.


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