ELISHA NJOMABA

Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Graduate Student

Followers

Following

Co-authors

Public Views

My main research and career interests are in the use of Remote Sensing technology to understand issues such as quantification of global forest change and land surface dynamics, effects of anthropogenic activities on terrestrial ecosystems and resources among others using methodological approaches like Time-series analyses, evaluation of optical and SAR data, analysis of large remote sensing data archives and mass data processing, Machine learning techniques.
Address: Vetrniku 1834/18

less

Uploads

Papers by ELISHA NJOMABA

Assessing Forest Species Diversity in Ghana's Tropical Forest Using PlanetScope Data

by ELISHA NJOMABA, James Ofori, and Ben Aikins

Remote Sensing (ISSN: 2072-4292), 2024

This study utilized a remotely sensed dataset with a high spatial resolution of 3 m to predict sp... more This study utilized a remotely sensed dataset with a high spatial resolution of 3 m to predict species diversity in the Bobiri Forest Reserve (BFR), a moist semi-deciduous tropical forest in Ghana. We conducted a field campaign of tree species measurements to achieve this objective for species diversity estimation. Thirty-five field plots of 50 m × 20 m were established, and the most dominant tree species within the forest were identified. Other measurements, such as diameter at breast height (DBH ≥ 5 cm), tree height, and each plot’s GPS coordinates, were recorded. The following species diversity indices were estimated from the field measurements: Shannon–Wiener (H′), Simpson diversity index (D2), species richness (S), and species evenness (J′). The PlanetScope surface reflectance data at 3 m spatial resolution was acquired and preprocessed for species diversity prediction. The spectral/pixel information of all bands, except the coastal band, was extracted for further processing. Vegetation indices (VIs) (NDVI—normalized difference vegetation index, EVI—enhanced vegetation index, SRI—simple ratio index, SAVI—soil adjusted vegetation index, and NDRE—normalized difference red edge index) were also calculated from the spectral bands and their pixel value extracted. A correlation analysis was then performed between the spectral bands and VIs with the species diversity index. The results showed that spectral bands 6 (red) and 2 (blue) significantly correlated with the two main species diversity indices (S and H′) due to their influence on vegetation properties, such as canopy biomass and leaf chlorophyll content. Furthermore, we conducted a stepwise regression analysis to investigate the most important spectral bands to consider when estimating species diversity from the PlanetScope satellite data. Like the correlation results, bands 6 (red) and 2 (blue) were the most important bands to be considered for predicting species diversity. The model equations from the stepwise regression were used to predict tree species diversity. Overall, the study’s findings emphasize the relevance of remotely sensed data in assessing the ecological condition of protected areas, a tool for decision-making in biodiversity conservation.

Download

Mapping of sacred groves in Ghana: the case of Talensi district in the guinea ecological zone

SN Social Sciences

Sacred groves are a means of conservation or sustainability of natural resources through cultural... more Sacred groves are a means of conservation or sustainability of natural resources through cultural beliefs or spiritism; hence, their essence and timeliness in current literature or conservation in developing countries. Despite recent interest in sacred groves, few studies have explored the spatial distribution of sacred groves. Considering this, the current study mapped the geographic distribution of sacred groves in the Talensi area of Ghana&#39;s Upper East Region. The study relied on in-depth interviews and a Global Positioning System (GPS) device as the main instruments of primary data collection. Purposive sampling was used to choose the 20 participants for the study from the Talensi district, including 4 Tengdanam and 16 elderly men who owned family groves, had in-depth knowledge of sacred groves, and frequently visited such groves. The results validated the conceptualization of sacred groves through the saturation theory. Through this study, it was discovered that the research area&#39;s sacred groves were affected by a confluence of modern religion and climate. Sacred groves in the study area were shown to be significantly impacted by a variety of modern religions. Findings further revealed that the spatial pattern of the distribution of sacred groves in the study area was clustered. This paper urges the effective implementation of conservation measures to stop further deterioration of the sacred groves in the studied region. Also, the indigenes should be sensitized on the relevance of sacred groves to the environment.

Land Use Land Cover Change within Kakum Conservation Area in the Assin South District of Ghana, 1991-2015

West African Journal of Applied Ecology, Sep 1, 2018

Kakum Conservation Area is roughly 1187km 2 , extending over large portions of forest reserves in... more Kakum Conservation Area is roughly 1187km 2 , extending over large portions of forest reserves in the Assin South District of Ghana. The district hosts the remaining biodiversity hotspots within highly fragmented rainforest of West Africa. Although the conservation has been gazetted as protected area, it has since been impacted by illegal chainsaw logging, expanding agricultural land use and built construction to meet the housing needs of the rapidly growing population of the district. However, there is paucity of data on the magnitude, rate and types of land cover change occurring in the district. This study seeks to address these by examining the magnitude, the rate and direction of change in land cover between 1991 and 2015. The study objective was achieved using supervised classification and post classification change detection of remotely sensed Landsat satellite imagery of the district taken in 1991, 2001 and 2015. The results show that, within the study period, the population of the area increased by 2.9%, thick forest decreased by 8.2km 2 , light forest increased by 5.3km 2 and built environment increased by 2.9km 2 per annum. These results are considered potential hindrance to sustainable development, including biodiversity conservation in the forest reserves and climate change mitigation in general. There is therefore need for measures to end deforestation and stimulate reforestation of the lost forest cover. The district needs to initiate an enquiry into the effectiveness of the current forest reserve management practices and sustainability of land use systems in the district.

Download

Mapping Perennial Crops in Africa: A Case Study of Oil Palm in Ghana

Journal of Geography, Environment and Earth Science International, 2021

Forests in Sub-Saharan Africa are experiencing some of the highest rates of deforestation and deg... more Forests in Sub-Saharan Africa are experiencing some of the highest rates of deforestation and degradation in the world, with most natural forest species being replaced by cropland and plantation monoculture. In this work, a method was developed that combined the Synthetic Aperture Radar (Sentinel-1) and optical satellite imagery (Sentinel-2) data to accurately map natural forest and perennial crops (oil palm) in Ghana. This was done using all three variables including spatial, spectral, and temporal variables to assess the most important variables in characterizing oil palm and natural forest, as well as the added value of sentinel-1 SAR data in a sentinel-2 optical-based classification. In this workflow, the Gray level co-occurrence matrix (GLCM) was calculated as representing textural/spatial variables, a yearly median composite to represent the spectral variables, and raining and dry season composites of Normalized Difference Vegetation Index (NDVI) and Normalized Difference Moi...

Download

Land Use Land Cover Change within Kakum Conservation Area in the Assin South District of Ghana, 1991-2015

West African Journal of Applied Ecology , 2018

Download

Mapping Perennial Crops in Africa: A Case Study of Oil Palm in Ghana

Journal of Geography, Environment and Earth Science International, 2021

This work was carried out in collaboration among all authors. Author EN designed the study, perfo... more This work was carried out in collaboration among all authors. Author EN designed the study, performed the remote sensing analysis, wrote the protocol and wrote the first draft of the manuscript. Authors JN and BEA managed the literature searches and assisted with the training and validation data collection. All authors read and approved the final manuscript.

Download

Response of Rice to Sulfur and Zinc Applications Under Fallowed and Continuously Cropped Soils in Northern Ghana

International Journal of Plant and Soil Science, 2021

The influence of zinc and sulfur on growth and yield of rice was studied for two soils; fallowed ... more The influence of zinc and sulfur on growth and yield of rice was studied for two soils; fallowed and continuously cropped. It was a 2 x 4 x 4 factorial experiment laid out in a randomized complete block design with three replicates, using lixisols of northern Ghana. Sulfur was applied as Sodium Sulfate (Na2SO4) at 0, 10, 20, 30 kg S/ha, two days after transplanting. Whilst zinc was applied as Zinc oxide (ZnO) at 0, 4, 8, 12 kg Zn/ha before transplanting. All soils received same rates of NPK (90-60-30 Kg/ha). An initial physico-chemical analysis conducted on the soils revealed that, both were sandy loam in texture and low in zinc but moderately high in sulfur. The fallowed soil was high in all other measured soil nutrients except nitrogen when compared to the cropped soil. The experimental results showed that, rice growth (tiller number, plant height), grain yield parameters (panicle count, percentage filled grains, grain yield) and straw yields are maximized by at least inclusion of...

Download

Assessing Forest Species Diversity in Ghana's Tropical Forest Using PlanetScope Data

by ELISHA NJOMABA, James Ofori, and Ben Aikins

Remote Sensing (ISSN: 2072-4292), 2024

Download

Mapping of sacred groves in Ghana: the case of Talensi district in the guinea ecological zone

SN Social Sciences