Environmental & Physical Sciences

Research Papers/Topics Environmental & Physical Sciences

Effects of pea aphid secondary endosymbionts on aphid resistance and development of the aphid parasitoid Aphidius ervi: a correlative study

Abstract In order to reduce parasite-induced mortality, hosts may be involved in mutualistic interactions in which the partner contributes to resistance against the parasite. The pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae), harbours secondary bacterial endosymbionts, some of which have been reported to confer resistance against aphid parasitoids. Although this resistance often results in death of the developing parasitoid larvae, some parasitoid individuals succeed in develo...

Infestation Levels and Molecular Identifcation Based on Mitochondrial COI Barcode Region of Five Invasive Gelechiidae Pest Species in Kenya

Abstract Invasive Gelechiidae pest species, namely Tuta absoluta, Phthorimaea operculella, Aproaerema simplixella, Sitotroga cerealella, and Pectinophora gossypiella are among the major constraints hampering agricultural economy in Kenya. Infestation levels were determined on respective host crops sampled from different localities and P. operculella recorded the highest infestation of 68.00 ± 4.92% on stored potato. Aproaerema simplixella and T. absoluta accounted for 61.33 ± 5.35% and 51....

Variation in Seagrass Carbon Stocks Between Tropical Estuarine and Marine Mangrove-Fringed Creeks

Abstract Seagrass and associated blue carbon ecosystems are important carbon sinks, and hence understanding their spatial and temporal variability is vital in appreciating their potential roles in climate change mitigation and adaptation. The Indo-Pacific region has the highest seagrass biodiversity, yet little focus has been made to compare seagrass habitat extent and carbon dynamics with their temperate counterparts. The present study assessed habitat characteristics and seagrass species ...

Seagrass Loss and Sub-Surface Carbon Fate: Insights from a Long-Term Experimental Removal in Gazi Bay, Kenya

Abstract Seagrass meadows are considered as global hotspots of blue carbon stocks. However, they suffer global cover loss mainly due to anthropogenic activities. Few is known on the impact of seagrass loss on their blue carbon stocks. This study investigates the impact of seagrass removal on soil organic carbon stocks two years after initial perturbation, and the potential bioturbation activity of co-existing burrowing shrimps in Gazi Bay, Kenya. Seagrass aboveground biomass was removed for ...

Indigenous knowledge on host tree preference of the wild edible Gynanisa maja (Lepidoptera: Saturniidae) matches with the laboratory test results in western Zambia

Abstract/Overview Gynanisa maja is an edible caterpillar and contributes significantly towards household food security. The linkage between indigenous and scientific knowledge influencing G. maja forage preference is not yet clear, and therefore the study aimed at determining this linkage regarding host preferences for G.maja in western Zambia. A household survey was conducted to determine people’s perception on the most preferred host plants and in order to compare with the laboratory ...

Processed products of termites and lake flies: Improving entomophagy for food security within the Lake Victoria region

Abstract/Overview Among the factors contributing to food shortage in Africa are lack of appropriate preservation and storage facilities, tropical heat and poor road network for marketing produce. High food spoilage caused by high temperatures of the tropical areas necessitates storage for all householders. Marginal areas of Lake Victoria often suffer protein deficiency due to dependence on narrow base sources of protein, most of which get spoilt during storage. The lake region is endowed ...

An analysis of socio demographic and agronomic factors associated with adoption of improved mango varieties among small scale farmers in Alego Usonga sub-county

Abstract/Overview The adoption of improved mango in Alego Usonga was still low covering an area of 12 Ha out of 47800 Ha of the arable land constituting only 0.025 %. The objective of this study was to determine the agronomic and demographic factors that influence adoption of improved mango varieties in Alego Usonga Sub County. The study adopted a cross sectional design to interview selected mango farmers who adopted planting of improved varieties. The study population was 320 famers with...

Edible Crickets (Orthoptera) Around the World: Distribution, Nutritional Value, and Other Benefits—A Review

Abstract/Overview Edible crickets are among the praised insects that are gaining recognition as human food and livestock feed with a potential of contributing to food security and reduction of malnutrition. Globally, the sustainable use of crickets as food or feed is undermined by lack of information on the number of the edible crickets, the country where they are consumed, and the developmental stages consumed. Furthermore, lack of data on their nutritional content and the potential risk...

The effects of long-term burning regimes on savanna spider assemblages

Abstract: Fire is an important disturbance in many biomes throughout the world and plays a major role in savannas, where it affects the composition and structure of vegetation, which in turn structures faunal assemblages. Higher intensity and more frequent fires tend to simplify habitat structure, leading to a decrease in faunal abundance and diversity. Fire is often used as a tool in conservation areas, but the effects of fire, in particular long-term burning regimes, on fauna is largely un...

Reservoir sedimentation in an arid and semi-arid river basin; a case study of Kalundu dam in Kitui County, Kenya

Abstract: In Kenya, several water reservoirs located in arid and semi-arid lands (ASALs) are undergo the trouble of accumulation of sediments. Kalundu Dam in Kitui County is a typical reservoir located in ASAL that has been experiencing periodic siltation since 1950s when it was commissioned. However, the patterns of siltation within the dam including the hydrological processes influencing sedimentation processes have not been investigated in this reservoir as with other reservoirs in Kenya�...

Study of commercial banks’ responses to climate change; a case of commercial banks in Kitui County Kenya

Abstract: The world has set targets to reduce the global warming that requires every sector of the economy to take measure to mitigate climate change. Banks and other financial institutions can play a central role in achieving these targets since climate change presents financial risks that should be treated accordingly. To assess and manage these risks, banks should apply scenario analysis and adopt climate related risk disclosure recommendations. This study analysed how Commercial banks op...

Comparative growth and productivity evaluation of phoenix oyster mushroom (pleurotus sp.) under residual agro-waste substrates in semi-arid lands of Kenya

Abstract: Two major challenges facing arid and semi-arid areas (ASALs) of Kenya today are food insecurity and poverty, occasioned by low agricultural production. Diversification into low input agriculture like mushroom cultivation can help address these challenges. However, commonly used mushroom substrates in Kenya, (rice and wheat straws) are not widely and cheaply available. Several crop residues are found in the ASALs, while Melia volkensii is becoming popular agroforest trees in these a...

Assessing end of life vehicles’ environmental management systems in Kenya: the case of Nairobi city county waste management streams

Abstract: There is a growing evidence that some older cars are smuggled to the country, which is likely to cause serious environmental effects since the rise of the older motor vehicle population in the country results in the volume of ELV waste and hence the need to assess the ELV waste streams, especially in Nairobi City County of Kenya. Therefore, this study aimed at assessing the End-of-Life Vehicles’ (ELV) Environmental Management Systems in Nairobi City County, Kenya. The study used ...

Effect of salt harvesting on ground water quality in Gongoni, Kilifi county

Abstract: Fresh water is essential for the existence and development of any community. In Gongoni, Kilifi County, groundwater forms the primary source of fresh water. The presence of salt harvesting activities in the area and the concentration of pit latrines within their vicinity pose major pollution risks to these water sources. Salt harvesting ponds, which play a key role in concentrating sea water during the salt harvesting process, have a potential of affecting the quality of ground wat...

Environmental effects and health risks associated with the location of Kalundu dumpsite, Kitui county to local residents

Abstract: The rapid growth of urban centres of developing countries has created challenging problems in waste management. This problem is exacerbated by resource constraints, extreme poverty, lack of practical waste management policies, and the inability of local authorities to provide for this basic function. Waste disposal onto dumpsites located in close proximity to human settlements is a challenge to the local inhabitants. In Kitui, generated waste is dumped in Kalundu, located in a resi...


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