Using multiple linear regression techniques to quantify carbon stocks of fallow vegetation in the tropics

Fallow ecosystems provide a significant carbon stock that can be quantified for inclusion in the accounts of global carbon budgets. Process and statistical models of productivity, though useful, are often technically rigid as the conditions for their application are not easy to satisfy. Multiple regression techniques have been applied to study some biophysical phenomena but yet to be applied to carbon stock estimation. Using ecological data from 28 sampling locations, the study applied the stepwise multiple regression technique to identify ecological variables that wouldexplain carbon stock of fallow vegetation, aged between 3 and 8 years. The procedure generated three predictive regression models. The full model, could explain nearly 98% of variability of carbon stock (R2 = .979), using cationexchange capacity and total nitrogen content of soil and leaf area index as the three predictor variables. Sampling inaccuracies could have contributed to the error component of models and sample size increase has been suggested forreduction of such errors. The advantage of the method is its simplicity. The paper suggests that the derived models be validated before broad application. Also, the cost-effectiveness of the approach should be tested against other approaches

Mapping vulnerability to multiple hazards in the Savanna Ecosystem in Ghana

The interior savannah ecosystem in Ghana is subjected to a number of hazards, including droughts, windstorms, high temperatures and heavy rainfall, the frequency and intensity of which are projected to increase during the 21st century as a result of climate variability and change. Vulnerabilities to these hazards vary, both spatially and temporally, due to differences in susceptibilities and adaptive capacities. Many mapping exercises in Ghana have considered the impacts of single hazards on single sectors, particularly agriculture. But the hazards often occur concurrently or alternately, and have varying degrees of impacts on different sectors. The impacts also interact. These interactions make mapping of the vulnerabilities of multiple sectors to multiple hazards imperative. This paper presents an analysis of the spatial dimension of vulnerabilities by mapping vulnerability of sectors that support livelihood activities at a single point in time, using the Upper East Region of Ghana as a case study. Data colected to develop the maps were largely quantitative and from secondary sources. Other data drew on fieldwork undertaken in the region from July - September 2013. Quantitative values were assigned to qualitative categorical data as the mapping process is necessarily quantitative. Data were divided into susceptibility and adaptive capacity indicators and mapped in ArcGIS 10.2 using weighted linear sum aggregation. Agriculture was found to be the most vulnerable sector in all districts of the Upper East Region and experienced the greatest shocks from all hazards. Although all districts were vulnerable, the Talensi, Nabdam, Garu-Temapane and Kassena-Nankana West Districts were most vulnerable. Findings highlight the need for more targeted interventions to build adaptive capacity in light of the spatial distributions of vulnerabilities to hazards across sectors

Land cover change impacts on the abundance and composition of flora in the Densu basin

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Ecological assessment of carbon sequestration and partitioning in regenerating fallow system

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Sustainable Land Use Evaluation on Steep Landscapes and Flood Plains in the New Juaben District of Ghana: A GIS Approach.

Specific criteria arc stipulated and recommendations made for sustainable management of landscapes in Ghana. Yet, evaluation is scarcely conducted to determine whethcr real performance or land-use strategics arc meeting expected standards of sustainability. The paper reports on an evaluation study conducted on a landscape with various levels of slopes and flood plains. The study sought to demonstrate the application or information technology in achieving the objectives of sustainable land-use management. Landscape of the area was modeled in a Geographic Information System (GIS) environment. Slope was derived from digital elevation model (DEM) and spatially analyzed with land-use/cover information generated from satellite data. The performance of existing land-use was compared with expected land-use performance criteria for steep landscapes and flood plains. Steep slopes and areas within 100 m of the Densu River have been denuded of forest vegetation. Rather than making only a marginal use or geo-information technology in generating data, we must leverage its inherent analytical potentials that enable innovative, creative and enhanced management decisions for sustainable land resource use. Continually monitoring and evaluating the performance or land-resource utilization will provide feedback information necessary for directing resource use on sustainable trajectories

Tree species composition, richness and diversity in the northern forest-savanna ecotone of Ghana

Objective: Stand structure, composition, abundance and diversity of tree species of the northern forest-savanna ecotone were characterized to determine their spatial variability for land management.Methodology and result: An inventory of the in-situ tree community of the northern forest-savanna ecotone of Ghana was undertaken using the stratified random sampling technique. In all, 1453 individuals, representing 88 species, 78 genera and 30 families were identified in the study. Antiaris toxicaria, Adansonia digitata, Acacia albida, Afzelia africana and Vitellaria paradoxum were found most dominant in the vegetation. A gradation of tree distribution was evident as the ‘near-savanna’ portion of the ecotone was more species-rich than the ‘nearforest’ portion. Significant differences were observed of the species richness, densities and diversity of trees across sites (P < 0.05) and savanna trees were preponderant over forest species.Conclusion and application: This work has provided evidence of variability in tree species composition, richness, density and diversity across the northern forest-savanna ecotone of Ghana. The information could be crucial for monitoring and managing agro-ecosystems sustainability. A future study would be required to isolate proximate factors of tree species distribution in the ecotone.Key Words: composition, density, diversity, forest-savanna ecotone, Ghana, richness, tree species

Water quality analysis of rivers used as drinking sources in artisanal gold mining communities of the Akyem-Abuakwa area: A multivariate statistical approach

The spatial pattern of water quality of rivers affected by artisanal gold mining but used as drinking sources in Akyem Abuakwa, was evaluated based on thirteen variables. At nine of the fifteen sampling stations, concentrations of arsenic, mercury, total dissolved solids, turbidity, water colour, nitrate-nitrogen and phosphate-phosphorus were found to be higher than WHO’s limits for drinking water. Cluster analysis distinguished four water quality categories - good, fairly good, poor and grossly polluted. Only rivers Subri and Kadee were classified as “good” for drinking purposes. Discriminant analysis revealed that, in order of importance, turbidity, arsenic, temperature, phosphate-phosphorus and total dissolved solids are the most important variables for identifying drinking water quality of river sources. Principal component analysis identified five factors with eigenvalues greater than unity and accounting for more than 80 percent of water quality variability. Artisanal gold mining accounted for more than 26 percent of the variability, with arsenic and mercury as the primary contaminants in the area. Other sources of contamination are agricultural activities and domestic waste disposal. The study recommends that local water quality managers design cost-effective strategies to effectively monitor and protect drinking water resources of the study area, particularly from miningrelated degradation. Keywords: Artisanal Gold Mining; Drinking Water Quality; Multivariate Statistics; Akyem Abuakwa; Ghan

Comparing farmers’ perception of climate change and variability with historical climate data in the Upper East Region of Ghana

Perception of climate change and variability supported by local knowledge has helped to advance understanding of climate change and its impacts on agricultural land-use systems. This study compares farmers’ perception of climate change and variability in four communities of the Upper East Region of Ghana. Using a sample of 186 households from these four communities, farmers’ perception was compared with historical climatic data from the closest weather station of the study area. Also, logistic regressions were used to estimate factors that influence the perception of climate change and variability in the area. Findings show that 71% of respondents perceived an increase in temperature which matches with the climatological evidence. On the other hand, decreasing rainfall with a shortening period was observed by 95% of respondents. From the climatological data, no real evidence of reduction in the amount of rainfall was apparent due to the high inter-annual variability. Unlike the rainfall data, there is an agreement between climatological data and farmers’ observation that the onset of the rainy season is now shifting from April to June, accompanied by an increasing dry spell. In  contrast, there is a divergence concerning the length of the growing season which is explained by the strong influence of the onset rather than by the end of the rainy season. From the findings of the binary logistic analyses, the local topography and the information on weather and climate were significant in determining the likelihood of a good perception of climate change and variability. Therefore, for any policy directed at farmers to adopt adaptation measures to climate change, more attention should be given to the role of the local environment and access to climate-related information.Keywords: Adaptation, Climate change, Perception, Climatological evidence, Upper Eas