PhD Candidate, University of Buea


The relationship between economic growth and environmental degradation indicators, referred to in environmental economic literature as the Environmental Kuznets Curve (EKC) hypothesis has been widely investigated, with a plethora of studies finding enough evidence to support the hypothesis. However, many of these studies employ an aggregate measure of economic activity such as Gross Domestic Product (GDP) per capita, thus failing to establish empirical evidence of the hypothesis for disaggregated or sectoral measures of economic activities. Therefore, this work was motivated from the understanding that disaggregated measures of economic activities produce relatively specific environmental effects. It is in this regard that this study sets out to investigate in to the validity of the EKC hypothesis for total natural resources depletion in Sub-Saharan African (SSA) countries. The study uses panel data from 1981-2016 obtained from the World Development Indicators (WDI) of the World Bank. Natural resources rents and natural resources depletion were used as measures of economic activity and environmental degradation respectively. Panel unit root tests were conducted to test for stationarity of the variables and panel cointegration test was used to establish the presence of a longrun relationship among the variables. Based on the Hausman test, the panel fixed effects model was selected for empirical analysis. Results of the study confirm, contrary to expectation the absence of an inverted U-shaped relationship between rents from natural resources and natural resource depletion. A monotonically increasing relationship was found. The implication of this finding is that there is no point in time at which, exploitation of natural resources is going to be an asset and not a liability to the environment. It is recommended that the governments of SSA countries should design and implement strict environmental policies where they are absent and enforce these policies where they are present in a bit to mitigate the adverse effects of the exploitation of natural resources as well as other economic activities on the environment.


Insect community composition and functional roles along a tropical agricultural production gradient

Abstract: High intensity agricultural production systems are problematic not only for human health and the surrounding environment, but can threaten the provision of ecosystem services on which farm productivity depends. This research investigates the effects of management practices in Costa Rica on on-farm insect diversity, using three different types of banana farm management systems: high-input conventional system, low-input conventional system, and organic system. Insect sampling was done using pitfall and yellow bowl traps, left for a 24-h period at two locations inside the banana farm, at the edge of the farm, and in adjacent forest. All 39,091 individual insects were classified to family level and then morphospecies. Insect species community composition and diversity were compared using multivariate statistics with ordination analysis and Monte Carlo permutation testing, and revealed that each of the management systems were significantly different from each other for both trap types. Insect diversity decreased as management intensity increased. Reduced insect diversity resulted in fewer functional groups and fewer insect families assuming different functions essential to ecosystem health. Organic farms had similar species composition on the farm compared to adjacent forest sites, whereas species composition increasingly differed between farm and forest sites as management intensity increased. We conclude that while organic production has minimal impact on insect biodiversity, even small reductions in management intensity can have a significantly positive impact on on-farm insect biodiversity and functional roles supported.

Pub.: 30 Mar '18, Pinned: 31 Mar '18