Browsing by Author "Ng'endo, Rossa N."

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    Diversity and Abundance Patterns of Amphibians in Rehabilitated Quarries of Bamburi Near Mombasa (Kenya)
    (Research, 2013-11) Ong'oa, Dominic O.; Ng'endo, Rossa N.; Muya, Shadrack M.; Nyoike, Mathew M.; Malomz, Patrick K.; Osiemo, Zipporah L.
    Amphibians are sensitive to changes in the environment and are, therefore, excellent indicators of success in restoring degraded habitats. As such, a clear understanding on how amphibian populations respond to changes in the environment is required. In order for conservationists to establish if the declining trends are changing, biodiversity recovery studies are essential especially in reclaimed habitats. This study focused on the recovery of amphibians, particularly on frogs, in reclaimed quarries of the Bamburi Cement Plant near Mombasa whereby the diversity, species abundances and composition at different stages of quarry re-establishment were assessed. The study area was divided into three zones based on the 13-year interval since the beginning of the rehabilitation process. Transect surveys and time-constrained search and size method were used for sampling 20 randomly selected sites. Sampling was done during the rainy and the dry seasons, with searches conducted between 900 and 1,600 hours during the day and between 1,800 to 2,100 hours at night. Recording of basic morphological data of collected specimens was done in the field to aid in grouping specimens before voucher materials were preserved in 10% formalin and stored in 70% alcohol. Further identifications and confirmations matching specimens to species were carried out using specialized classification keys from the National Museum of Kenya. Twelve species were encountered across the three zones, with Ptychadena anchietae and Phrynobatrachus acridoides, respectively, the most abundant. It was also noted that amphibian diversity across the quarries was independent of the age of ecological re- establishment (r = -0.5). This is indicated by the higher amphibian diversity in the south and north quarries (N = 1050 and 506 respectively) despite their relatively younger age since re- establishment compared to the central quarry (N = 438). Lower diversity in the central quarry, although the oldest, may be largely attributed to human disturbance. Additionally, exotic plantations across the study area are poor in species since they are monocultures and, thus, not heterogeneous enough to support higher anuran diversity. Since amphibians act as one of the best measure of environmental health, rehabilitation process in the quarries need to embrace mechanisms that support maximum biodiversity recovery such as replanting of more indigenous tree species as opposed to only exotic monocultures.
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    Morphological variation of Ridged Frogs of the Taita Hills, Kenya
    (Firenze University Press, 2011-12) Ng'endo, Rossa N.; Kairu, Eunice; Osiemo, Zipporah L.; Ogol, Callistus
    Comparing of morphological character variation within taxa continues to play an important role in improving species inventories. Using morphometrical and non-meristic morphological adult characters, the diversity of the genus Ptychadena in Taita Hills was studied. Comparative material from elsewhere was not used, and therefore species names were only provisionally allocated to the taxa identified. Available names were discussed on the basis of comparisons with morphological data from other regions. The results revealed that female species are larger in size than males. Two species were identified and for each a standardized diagnosis of 32 characters is provided. Comparison of results with morphological data from related studies done elsewhere reveals that certain characters are of critical importance in differentiating the two Ptychadena species. The power of these morphological characters is discussed, especially for the background of rapid and easy identification of Ptychadena species in the field for conservation purposes.
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    Nematode metabolic footprints, ecological and functional indices in tropical maize-beans agro-ecosystems under different farming practices
    (Elsevier, 2020-10) Maina, Samuel N.; Karuri, Hannah W.; Ng'endo, Rossa N.
    Maize and beans contribute significantly to food security in Kenya. Farming practices used in production of these crops may affect nematode community assemblages and influence agricultural productivity. Information on response of nematofauna, particularly free-living nematodes, under various agronomic practices in Kenyan maize-beans intercrop is scarce. This study reports on the effects of farming practices on nematode community dynamics, ecological and functional indices, nematode metabolic footprints, and predator-prey relationship in maize-beans cropping systems in Mwea, Kenya. The field trials were set up in two seasons in a randomized complete block design with each treatment consisting of four replicates. The treatments included cow manure plus chemical fertilizer (CmDCF), cow manure plus wood ash (CmWa), cow manure combined with wood ash plus fertilizers (CmWaF), chemical fertilizers only (DNF) and unamended controls. Soil samples were collected at 0–20 cm depth at bimonthly intervals during 2018–2019. During the two seasons, 54 nematode genera were identified. Cephalobus, and Heterocephalobus (bacterivores), Labronema (omnivore) and Nygolaimus (predator) were abundant in CmDCF, CmWa, CmWaF, and DNF while Aphelenchus and Aphelenchoides (fungivores) were dominant in all treatments. Principal response curve analysis showed that CmWaF significantly reduced the population of Helicotylenchus, Scutellonema and Rotylenchulus during the 2nd and 4th month in the second season. Renyi diversity analysis indicated that CmWaF had higher diversity of omnivores while functional metabolic footprints categorized it as structured in both seasons. Predator-prey analysis suggested that CmWa and CmWaF have the potential to provide suitable conditions for predators, target prey and amplifiable prey biomass. This study provides an insight on the implication of farming practices, on nematode abundance and soil food web in two economically important crops in Kenya. It also provides a basis for exploring the potential role of organic amendments containing cow manure in control of plant parasitic nematodes in maize-beans cropping systems.
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    Staff Profile: Dr. Rossa N. Nyoike
    (University of Embu, 2017-09) Ng'endo, Rossa N.
    Holds a Ph.D. in the field of Animal Ecology from Philips University of Marburg in Germany, and a Masters of Science degree from Kenyatta University in the same field. She is a lecturer at University of Embu, in the Department of Biological Sciences and has previously worked as a lecturer at The Catholic University of Eastern Africa. She has done research in areas of taxonomy and biodiversity of amphibians and ants. Her two latest publications are on Diversity and Abundance Patterns of Amphibians in Rehabilitated Quarries of Bamburi Near Mombasa (Kenya) and DNA barcodes for species identification in the hyperdiverse ant genus Pheidole (Formicidae: Myrmicinae)