Influence Of Light Pollution And Biodiversity Awareness On Hawkmoth (Lepidoptera: Sphingidae) Diversity And Abundance In Selected Sites In Kenya

ABSTRACT

Light pollution is a key biodiversity threat and is defined as one of the global environmental problems threatening key species to extinction and posing a major challenge to biodiversity conservation. The absence of stringent law, good practice and nonexistent environmental standards on light pollution has been a major drawback to management of its effects on biodiversity. This study sought to establish the influence of light pollution and biodiversity awareness on hawkmoth diversity and abundance in Kenya with a focus on two sites, Alim High School within Mavoko Constituency and Mithanga, within Mwala Constituency in Machakos County, Kenya. It engrossed on three objectives; evaluation of the distribution pattern of hawkmoths based on the national insect reference collection at the National Museums of Kenya, determining the influence of light pollution on diversity and abundance of hawkmoths and evaluating the level of awareness by development projects on the impacts of light pollution on biodiversity in Machakos County. Descriptive research design as well as field experiments were adopted. Records were retrieved from hawkmoth specimens housed at the National Museums of Kenya. Field surveys using light trapping were done at two sites, the Alim High School and at Mithanga village. A sample of forty eight randomly selected Environment Impact Assessment (EIA) reports was obtained at the Machakos County NEMA office in Machakos town and outlined Environmental Management Plans reviewed for negative impacts on flora and fauna and possible mitigation measures. The results showed that the hawkmoth collection holds 3,540 hawkmoths records consisting of 210 species, 97 of which are from the whole of Kenya, 33 from the larger former Machakos District and 10 from Machakos County. Light trapping away from the street lights had 18 hawkmoth records consisting of 8 species, while the trap at the street lights had no hawkmoths recorded indicating a possibility of local extinction due to light pollution. A new species record Theretra capensis from Machakos County, was recorded at the Mithanga light trap. None of the EIA reports mentioned light pollution impacts or mitigation measures for light pollution. However, 62 % mentioned impacts and mitigation measures for flora only, 0% for fauna only, 10% for both flora and fauna and 38 % mentioned no issues on mitigation of impacts on flora and fauna. From this study results, it is concluded that hawkmoths are affected by light pollution and that development project proponents are not aware of light pollution and thus are not considering it in their impact mitigation plans. Among the recommendations given is that further field surveys be undertaken to examine hawkmoth species diversity and abundance in differently illuminated geographic areas capturing the effects of light pollution in their population dynamics.