scholarly journals Analysis of Forest Landscape Fragmentation in Samosir Island, North Sumatra

Author(s):  
Samsuri ◽  
A Zaitunah ◽  
J. F Manurung
2019 ◽  
pp. 1477-1496
Author(s):  
Jean-Fiston Mikwa Ngamba ◽  
Ewango Corneille Ekokinya ◽  
Cush Ngonzo Luwesi ◽  
Yves-Dady Botula Kahindo ◽  
Muhogwa Jean Marie ◽  
...  

This study assessed the impact of human activities on deforestation and sustainability of water resources and livelihoods in the Congo Basin. It mainly aimed to assess forest degradation in the Yoko reserve from 1976 to 2015 and investigate the compatibility of Landsat imagery for forest monitoring. Digital Image processing for unsupervised classification was done using ENVI software while supervised classification was done by means of ArcGIS 10. Results show that forest landscape faced large scale human induced fragmentation over the last 40 years. If these trends continue, they will affect the sustainability of water resources and livelihoods in the Congo Basin of the Democratic Republic of Congo. Hence, policy makers need to look at key drivers and address impacts that may threaten the future of Hydrological Ecosystems Services, including water and land resources in the Congo Basin. Authorities have to apply an Integrated Management of Water, Land and Ecosystems.


2012 ◽  
Vol 546-547 ◽  
pp. 1080-1085
Author(s):  
Xiao Hong Yuan ◽  
Ji Ping Li ◽  
Jian Jun Li ◽  
Ping Fang Zhang

Defined the parameters of forest landscape according to the characteristic of forest landscape pattern combined with complex networks theory. By using landscape blocks as nodes, the affect between plaques as lines, a coupling network modeling of forest landscape plaques is established. Taking the west Tongting Lake in Hunan province as the study area, divided the landscape pattern into 13 types, established a plaques coupling network by using the patch edge effects between two different type of blocks as power of lines. It shows that the degree of node, the indexes of landscape classification has positive relationship with the power of node, the degree of node has positive relationship with the importance of node, the area of landscape has complicated competition with the landscape fragmentation when contributes to the concentration degree.


2019 ◽  
Vol 20 (10) ◽  
Author(s):  
SAMSURI SAMSURI ◽  
ALFAN GUNAWAN AHMAD ◽  
ANITA ZAITUNAH ◽  
HALIZA KHAIRUNI TAMBUSAI

Abstract. Samsuri, Ahmad AG, Zaitunah A, Tambusai HK. 2019. Evaluation of suitability of plant species for lowland forest landscape restoration in Lepan watersheds, Langkat District, North Sumatra, Indonesia. Biodiversitas 20: 2903-2909. Lepan watersheds have high management priority in North Sumatra due to healthy biophysical, socio-economic conditions and issues. Many human activities, such as conversion of forest land into settlements and oil palm plantations have resulted in decreasing the ecological functions of the forest landscape. Therefore, it is necessary to initiate efforts and actions to preserve the environment in order to prevent further damage. The effort required is to restore the already damaged ecosystem with the cultivation of species of plants in accordance with the land and soil conditions of the Lepan watersheds. Four criteria are used for determining suitable plants that can be planted as well as cultivated by the community. They are plant species found in natural forests, plant species meeting the physical and soil characteristics, plant species cultivated by community and plant species based on community perceptions. Species matching was determined by scoring and weighting method. This study found that the most suitable species for restoration activities based on these four criteria is Pterospermum subpeltatum.


Author(s):  
Jean-Fiston Mikwa Ngamba ◽  
Ewango Corneille Ekokinya ◽  
Cush Ngonzo Luwesi ◽  
Yves-Dady Botula Kahindo ◽  
Muhogwa Jean Marie ◽  
...  

This chapter assessed the impact of human activities on deforestation and sustainability of water resources and livelihoods in the Congo Basin. It mainly aimed to assess forest degradation in the Yoko Reserve from 1976 to 2015 and investigate the compatibility of Landsat imagery for forest monitoring. Digital image processing for unsupervised classification was done using ENVI software while supervised classification was done by means of ArcGIS 10. Results show that forest landscape faced large-scale human-induced fragmentation over the last 40 years. If these trends continue, they will affect the sustainability of water resources and livelihoods in the Congo Basin of the Democratic Republic of Congo. Hence, policymakers need to look at key drivers and address impacts that may threaten the future of hydrological ecosystems services, including water and land resources in the Congo Basin. Authorities have to apply an integrated management of water, land, and ecosystems.


2020 ◽  
Author(s):  
Vasilică-Dănuț Horodnic ◽  
Vasile Efros ◽  
Dumitru Mihăilă ◽  
Luminița-Mirela Lăzărescu ◽  
Petruț-Ionel Bistricean

<p>Landscape fragmentation is the expression of patchiness and spatial heterogeneity of land cover pattern. After the breakdown of the socialism regime in 1989, Romania has undergone significant changes at the level of political, institutional and socio-economic profile, which determined researchers to consider this country an experimental territory for land use and landscape research.</p><p>The aim of present study is to detect hotspots of changes of forests landscape fragmentation patterns in the Romanian Carpathian Mountains over the last 28 years. In order to meet our demand we applied a holistic approach to assess the multiple teleconnections between forest cover changes and the degree of fragmentation at regional scale for two distinct periods that make up the 1990-2018 period: (1) 1990-2006 (land restitution period or transition period to the market economy) and (2) 2006-2018 (post-accession period to the European Union).</p><p>The analysis were carried out using freely available time series CORINE Land Cover data of 1990, 2006 and 2018 provided by Copernicus Land Monitoring Services. The initial spatial datasets were processed with the help of Geographic Information Systems (GIS), while GUIDOS, a free software toolbox dedicated to quantitative analysis of digital landscape images, was used to generate spatial and statistics data of the degree of forest landscape fragmentation.</p><p>Our findings indicate that the first period of analysis was more dynamic regarding forest cover changes with a gross area gain of 316 304 ha (7.59%) and a gross area loss of 147 496 ha (3.54%) leading to a net forest area change of 168 808 ha (4.05%) which reflects the level of forest recovery. The change pattern of fragmentation classes showed that 332 045 ha (71.47%) of fragmentation decrease is found for the transition of dominant forest in 1990 into the less fragmented class interior in 2006, while 67 418 ha (65.10%) of all fragmentation increase is found for transition from interior in 1990 to dominant in 2006. The other side, for the period from 2006 to 2018 we found a gross area gain of 127 146 ha (2.93%) and a gross area loss of 212 933 ha (4.91%) leading to a net forest area change of -85 787 ha (-1.98%) which emphasizes the level of forest disturbance. In the same time frame, the high values of fragmentation pattern have been registered for the same classes, 56.82% for fragmentation decrease and 70.60% for fragmentation increase, respectively. The results highlight the reversible impact of land use change on land cover pattern, spatially shaped through afforestation in the first period of analysis and through deforestation in the second period. The afforestation process were determined by high rate of external migration, while deforestation process is a consequence of land restitution laws (Law no. 247/2005), which caused considerable mutations in the ownership of land.</p><p>The study emphasizes the impacts of land use policies and land management practices on the pattern of forest landscape and the usefulness of Guidos Toolbox, a universal digital image object analysis, to detect hotspots of changes at regional scale.</p>


Author(s):  
Jean-Fiston Mikwa Ngamba ◽  
Ewango Corneille Ekokinya ◽  
Cush Ngonzo Luwesi ◽  
Yves-Dady Botula Kahindo ◽  
Muhogwa Jean Marie ◽  
...  

This study assessed the impact of human activities on deforestation and sustainability of water resources and livelihoods in the Congo Basin. It mainly aimed to assess forest degradation in the Yoko reserve from 1976 to 2015 and investigate the compatibility of Landsat imagery for forest monitoring. Digital Image processing for unsupervised classification was done using ENVI software while supervised classification was done by means of ArcGIS 10. Results show that forest landscape faced large scale human induced fragmentation over the last 40 years. If these trends continue, they will affect the sustainability of water resources and livelihoods in the Congo Basin of the Democratic Republic of Congo. Hence, policy makers need to look at key drivers and address impacts that may threaten the future of Hydrological Ecosystems Services, including water and land resources in the Congo Basin. Authorities have to apply an Integrated Management of Water, Land and Ecosystems.


MBIA ◽  
2019 ◽  
Vol 17 (3) ◽  
pp. 17-24
Author(s):  
Cut Ermiati ◽  
Dita Amanah ◽  
Dedy Ansari Harahap ◽  
Fitriani Tanjung

This study aims to determine the effect of career development and work placement on employee work performance at PDAM Tirtanadi, North Sumatra Province. The population in this study were all employees per division, amounting to 182 employees. From the total population can be determined the number of samples in this study amounted to 65 people. The data analysis technique used is the t-test, f-test, multiple linear regression and determinant coefficient test using SPSS 22. From the calculation results using SPSS shows that there is an influence of career development on employee work performance, there is the influence of work placement on employee performance and there is the influence of career development and work placement on employee performance.


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