Natural Resources Management

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A botanical inventory and diversity assessment of Mt. Marsabit forest, a sub-humid montane forest on the arid lands of northern Kenya
(Wiley, 2007) Githae, E. W.; Chuah-Petiot, M.; Mworia, J. K.; Odee, D. W.
A botanical inventory and diversity of trees, shrubs (≥5 cm diameter at breast height [dbh]), herbs,climbers and lianas was assessed in plots (154) of 20 × 5 m in Mt. Marsabit forest, northern Kenya. Werecorded 52 species of trees and shrubs, twelve species of herbs and six species of climbers and lianas.They belonged to 35 families and 64 genera. Rubiaceae was the richest family with nine species followedby Euphorbiaceae (six), Oleaceae (five), Rutaceae (four), Capparaceae, Labiatae and Leguminosae (threeeach). The rest of the families were represented by one or two species. Rinorea convallarioides (Bak.f.)Eyles ssp. marsabitensis Grey-Wilson (Violaceae), an endemic species, and Drypetes gerrardii Hutch.(Euphorbiaceae), were the two most important species, accounting for more than third of the combinedimportance value. Species diversity indices were 2.735 (Shannon–Wiener), 0.88 (Simpson's) and 0.296(Evenness). There was a strong evidence of disturbance arising from anthropogenic and wildlife foragingactivities. This inventory has affirmed Mt. Marsabit forest as a unique habitat for several endemic, rare,threatened or vulnerable plant species, which should be conserved.
A Review of Toxic Metals and Hazardous Organics in Wood Treatment Sites and Their Etiological Implications
(Journal of Chemical Reviews, 2022-02-07) Miranji, Edwin K.; Kipkemboi, Pius K.; Kibet, Joshua K.
Increased natural and human activities over the last century have led to excess levels of inorganic and organic pollutants into the environment and natural ecosystems. This review critically examines heavy metal and organic pollutants' role in wood treatment sites and their etiological consequences. These pollutants are not only recalcitrant but also tenacious to degradation under ordinary conditions. Although some heavy metals are essential to human health, they are toxic at elevated concentrations. Heavy metals feature carcinogenic properties and cause serious health risks to live systems and the environment because of their bio-accumulative, non-degenerative, and refractory characteristics. On the other hand, organic pollutants are readily introduced into the ecosystem from irresponsible use of detergents, volatile organic compounds, paints, pesticides, and wood preservatives. During the wood treatment process, various chemicals are used to enhance durability. Nevertheless, the use of wood preservatives such as chromated copper arsenate (CCA) and pentachlorophenol (PCP) potentially induces pollutants considered detrimental to human health and the ecological environment. Remediation of wood treatment sites using phytomanagement strategies and nanotechnologies has been presented in this review. Therefore, some challenges and recommendations for further research and applications are herein presented.
An Examination of the Nature of Sand Harvesting Conflicts and their Influence on Poverty Alleviation Initiatives in Makueni County, Kenya
(IISTE, 2015) Muthomi, Simon; Okoth, Pontian; Were, Edmond; Vundi, Silvia
Though natural resources play an important role in the economies of many countries, conflicts associated with their access continue to contribute to poverty in many African countries. While studies confirm conflict-poverty nexus for high value natural resources, scanty information is available on the low value resources. This study, therefore, examined one such low value resource – sand. The objective was to examine the nature of sand harvesting conflicts and their influence on poverty alleviation initiatives in Makueni County. The study employed descriptive and historical designs. The study was guided by the Resource Curse and Poverty Theories. The study sample comprised of 420 sand harvesters and several key informants. Data collection was done using questionnaires, interviews, focus group discussions and observation. Presentation of data was done using both quantitative and qualitative approaches. The study findings established that sand harvesting in Makueni County has been linked to violent conflicts which left many people either maimed, killed or without their property. These had increased poverty levels in the County. The study therefore recommends for establishment of appropriate institutions to mitigate on the conflicts in order to ensure that sand harvesting provides contributes to poverty alleviation in Makueni County.
Association between Anthropogenic Sources of Outdoor Air Pollution and Lichen Diversity, in Nakuru Town, Kenya
(Scientific & Academic Publishing, 2019) Kimani, Harriet W.; Moturi, Wilkister N.; Kariuki, Samuel T.
The purpose of this study was to assess urban lichen diversity in relation to anthropogenic sources of outdoor air pollution, in Nakuru town, Kenya. An ecological survey was conducted in six sampled sites of the town and data of lichen diversity and anthropogenic sources of outdoor air pollution, analyzed. Multi-stage sampling technique was used. A total of 51 lichen species were identified while 6 anthropogenic sources of outdoor air pollution were observed. Results from Fisher’s exact test analysis showed, significant association between the 6 observed anthropogenic sources of outdoor air pollution and lichen diversity. It was concluded that, different anthropogenic sources of outdoor air pollution affect presence and absence of urban lichen species. Hence, more studies on lichens and outdoor air pollution should be conducted in Kenya, to conclusively determine whether lichens should be adopted as an alternative biological method to technological devices, for assessing air pollution.
Biological control of desert locust (Schistocerca gregaria Forskål)
(CABI Reviews, 2021-03-06) Githae, Eunice W.; Kuria, Erick K.
Desert locust (Schistocerca gregaria Forskål) is one of the most serious agricultural pests in the world due to its voracity, speed of reproduction, and range of flight. We discuss the current state of knowledge on its biological control using microorganisms and botanical extracts. Metarhizium flavoviride was among the first fungus to be recognized as a bio-control agent against desert locust in the laboratory and field conditions. Nevertheless, its oil formulation adversely affected non-target organisms, hence led to further research on other microorganisms. Metarhizium anisopliae var. acridum (syn. Metarhizium acridum) is an environmentally safer bio-pesticide that has no measurable impact on non-target organisms. However, there are various shortcomings associated with its use in desert locust control as highlighted in this review. Bacterial pathogens studied were from species of Bacillus, Pseudomonas, and Serratia. Botanical extracts of 27 plant species were tested against the locust but showed varied results. Azadirachta indica and Melia volkensii were the most studied plant species, both belonging to family Meliaceae, which is known to have biologically active limonoids. Out of the 20 plant families identified, Apiaceae was the most represented with a frequency of 21%. However, only crude botanical extracts were used and therefore, the active ingredients against desert locust were not identified. Through a comprehensive research, an integrated pest management strategy that incorporates these bio-controls would be a realistic option to control desert locust infestations.
Conflict of Interest in Exploitation and Utilisation of Transboundary Natural Resources on Lake Victoria
(Digital Commons, 2016) Were, Edmond
The management of Lake Victoria as a “regional common” is expected to adhere to the global principles of transboundary natural resource management. However, national interest and power asymmetry amongst riparian states buoyed by external demand have overwhelmed global and regional norms leading to incessant exploitation of the common resources. This paper uses idealist and realist perspectives of power relations to inform the analysis of conflicting interests in transboundary natural resource exploitation. It partly relies on 2012-2013 primary data from purposively selected Beach Management Units in Kenya and Uganda and secondary data from regional fisheries institutions. Notwithstanding the normative value of global conservation principles, demand-driven globalization buttressed by national vested interests and the National Measures clause of the Lake Victoria Fisheries Organization have led to unsustainable exploitation of the shared resources on the lake. Lake Victoria thus epitomizes a clash of global and local interests in the use of shared natural resources.
Determination of Physico-Chemical Properties Of Sources of Water In Narok North Sub- County, Kenya
(International Science Community Association, 2015) Ndubi D. 1, Oyaro N. 2, Githae E.3 and Afullo. A.4
A study was conducted in Narok north sub-county, Kenya to analyze physico-chemical properties of water in various water sources in dry and wet season to determine water quality for domestic use. Properties analyzed included pH, temperature, DO, BOD, TDS, TSS and total hardness. The results indicated that most parameters fell within the accepted range according to WHO except for the BOD which indicated the presence of microorganisms and hence the water is not fit for human use unless treated prior to consumption.
EFFECT OF GULLY EROSION ON LIVELIHOODS IN SUSWA CATCHMENT, NAROK COUNTY
(International Journal of Current Research, 2017-05-31) Konana, Cn; Gachene, Ckk; David, D. M.; Mureithi, S. M.; Gicheru, P. T.; Khalif, Z.
This study investigated the effect of gully erosion on livelihoods in Suswa catchment, Narok County. Data was collected in 4 villages (Eluai, Olepolos, Olesharo and Enkiloriti) using a questionnaire on the effect of the gully on livelihoods (movement, infr effect of gully erosion on activities within the four villages was determined using Chi square test. Results showed that the effect of gully erosion on house activities differed significantly between the villages. This could be due to the fact that houses near to the gully where the most affected by runoff. The effect of gully erosion on farming, livestock, level of income, water availability, firewood collection, building materials, health and mosquito bree villages. This is because the effect on the mentioned livelihood activities was more or less the same in the 4 villages. According to community members the level of damage to farming, livestock, house activitie of erosion and its effects on their livelihoods. The low use of soil conservation measures in the Suswa catchment could have contributed to negative effects on livelih recommendations for the rehabilitation of the gully included the use of soil and water extension services, soil and conservation measures, training, the use of indigenous knowledge and reduction of livestock numbers and financial
Environmental Degradation’s Effect on the Gains Made in SDG6
(Springer International Publishing, 2021-02-23) Moturi, Wilkister Nyaora
Water is a vital limited resource for humanexistence, and the availability of adequate andsafe water ties strongly with the sustainabledevelopment concept. In the last 100 years, thedemand for water has increased six times andcontinues to grow at an annual rate of 1%(WWAP 2018). Sustainable Development Goal 6sets out to ensure availability and sustainablemanagement of water and sanitation for all.Water connects us all and is embedded in almostall the other SDGs, particularly those dealing withfood, energy, and the environment. It links theweb of the 17 SDGs and their 169 targets. Nolonger can water be addressed as a separate ele-ment in isolation from the other goals. But thisinterconnectedness has important implications. Itmeans that the Water Goal will only be achieved ifthe other goals are attained, and in turn, that otherSDGs will only be achieved if the water goal isattained (Ait-Kadi 2016).
Evaluation of Plant Growth on Expanded Black Cotton Soil
(The Premier Publishers, 2018-02-01) Nyakach, Samwel; Owido, Seth; Onyando, Japheth
In aggregate hydroponics, the suitability of a particular medium is often guided by its physical properties. However these may not provide adequate evaluation. By growing a crop, the growth characteristics can also be used to guide medium preparation and selection. Tomatoes (Anna F1 variety) were grown in containers under a greenhouse and provided with equal amount of nutrient solution. The expanded black cotton soil was prepared by mixing with rice husk at a ratio of 90:10, fired at 750oC for 30 minutes and size reduced to various textures. The crops planted in the expanded clay aggregates performed better than the black cotton soil both in terms of stem elongation and enlargement due to improved drainage, nutrient flow and aeration conditions. The root length density was 25654 m m-3 in black cotton soil, being the highest and lowest in the coarse aggregates which had 9433 m m-3.
Heavy Metal Levels in Nakuru Town and the Surrounding Farmland Soils
(Egerton University, 2021-05) Kipruto, Misoi Simion
Heavy metals input in soils has been found to present a serious agro-environmental concerns in areas of intensive industrial and agricultural activities and Nakuru town and its surrounding farmland soil is not an exception. High input of heavy metals beyond the threshold limit values is a potential health hazard to plants, and even to animals and human beings through the food chain. The source of heavy metals in soil is primarily the parent rock material, however significant increases may occur through anthropogenic activities. The main objective of this study was to investigate the presence and levels of total and extractable selected heavy metals such as cadmium, chromium, copper, nickel, lead, and zinc in soils of Nakuru town and the surrounding farmlands busing the flame atomic absorption spectrometric technique. The status of some soil chemical properties such as pH, percentage organic carbon and cation exchange capacity were also investigated using stipulated standard methods. The sampling was done randomly in triplicate from 8 sites within Nakuru town and 8 sites in the surrounding farmlands. The data obtained from the experimental analysis were subjected to both descriptive and inferential statistics. The study revealed the presence of heavy metals in Nakuru town and its surrounding farmland soils but they were in very low levels as compared to world health organization maximum permissible levels. The heavy metal concentrations levels were found to correlate(P≤ 0.05) with the chemical properties either positively or negatively. The levels of heavy metals in Nakuru town soils were observed to be generally higher compared to the levels in the surrounding farmland soils, industrial and domestic emissions being the main contributing factor. The levels of extractable metals in Nakuru town soils had an effect on the levels of extractable metals in the surrounding farmland. It can be concluded from this study that there is no risk of heavy metal toxicity in the study area but accumulation of these heavy metals over time in soil can exceed the stipulated levels hence posing a potential hazard.
Impacts of forest management type and season on soil carbon fluxes in Eastern Mau Forest, Kenya
(Wiley-Blackwell Publishing Ltd, 2018-11-24) Tarus, George K.; Kirui, Bernard K.; Obwoyere, Gilbert
The value of ecosystems functions performed by forests in the climate change era has prompted increasing attention towards assessment of carbon stocks and fluxes in tropical forests. The aim of this study was to understand how forest management approaches and environmental controls impacted on soil CO2 efflux in a tropical Eastern Mau forest which is one of the blocks of the greater Mau complex in Kenya. Nested experimental design approach was employed where 32 plots were nested into four blocks (disturbed natural, undisturbed natural, plantation and glades). In 10 m2 plots, data were collected on soil CO2 efflux, soil temperature and soil moisture using soda lime methods, direct measurement and proxy techniques, respectively. There was significant forest management type effect (F3,127 = 3.01, p = 0.033) and seasonality effect (t test = 3.31, df = 1, p < 0.05) on mean soil CO2 efflux. The recorded mean soil CO2 efflux levels were as follows: plantation forest (9.219 ± 3.067 g C M−2 day−1), undisturbed natural forest (8.665 ± 4.818 g C M−2 day−1), glades (8.592 ± 3.253 g C M−2 day−1) and disturbed natural forest (7.198 ± 3.457 g C M−2 day−1). The study concludes that managing a forest in plantation form is primarily responsible for forest soil CO2 efflux levels due to aspects such as increased microbial activity and root respiration. However, further studies are required to understand the role and impact of soil CO2 efflux on the greater forest carbon budget.
LAND USE AND LAND COVER CHANGE AND ITS IMPLICATIONS ON GULLY EROSION
(International Journal of Scientific Research and Innovative Technology, 2017) Catchment, IN Suswa; County, Narok; Konana, Charity; Gachene, C.; Mburu, D.; Mureithi, S.; Gicheru, P.
This study investigated land use and land cover change for the last 26 years in Suswa Catchment, Narok County using satellite imageries. Changes in land use and land cover (built up areas, agricultural land, grassland, bareland and shrubland) for 1985-2000, 2000-2011 and 1985-2011 were determined using Chisquare test. Results showed no significant changes in built up areas, agricultural land, bareland, grassland and shrubland during the period. Overall change of built up area, shrubland, bareland, agriculture increased in 26 years, while grassland decreased. Grasslands were therefore converted to build up areas, shrubland, bareland and agricultural areas during this period. An increase in built up area, bareland and agricultural land and a decrease in grassland are therefore drivers of gully erosion. A decrease in grassland results in an increase in soil erosion. Projections (2020) indicate a significant increase in built up area, agricultural land and bareland and a decrease of grassland.
Nitrogen Fixation by Natural Populations of Acacia Senegal in the Drylands of Kenya Using 15 N Natural Abundance
(Taylor & Francis, 2013-03-05) Githae, Eunice; Gachene, Charles; Omondi, Stephen
This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
Physico-chemical, Palynological Characterization and Valorization of Clay Soils from Aterait and Okwata villages in Teso South Constituency (Busia County) in Kenya
(The World Organization of Applied Sciences (WOAS ), 2020-06-14) Opuru, Francis; Wafula, Peter; Amwana, Sharon
Clay soil has vast application especially in the manufacture of ceramics and refractory bricks. Samples of clayed materials from Okwata (AT1) and Aterait (AT2) villages in Teso South Constituency in Kenya were characterized for valorization. Several trial tests were done on the test specimens at varied temperatures. Considering the particle size analysis, the study revealed that clayed materials have non-congested particle size and their plasticity index lies between 17 and 48. Based on the mineralogical study, the samples showed the presence of feldspars, hematite, Kaolin, illite, and Quartz. The sandy nature of these clays is explained by high levels of silica content. The density and linear shrinkage increases with temperature while compressive strength decreases with temperature. Considering the analyses done on ceramic materials after firing, the study recommends that clay content are fit for the manufacture of refractory bricks.
Prevalence of Canid Gastrointestinal Helminths Eggs in Soils from Playgrounds within Kisii Municipality, Kenya
(Research & Reviews, 2015-10-12) Nyamongo, Onkoba W.; Nyarangob, Robert M.
Human zoonosis threatens public health disease surveillance, management, control and eventual elimination. Nowadays, people and pets share private and public utilities oblivious of the potential risk of zoonotic pathogen transmissions. Toxocariasis is one of the most prevalent zoonotic helminthic infections that are transmitted by cats and dogs through soils contaminations. The present study sought to determine the extent at which soils from playgrounds in Kisii municipality, Kenya are contaminated with eggs of canid gastrointestinal helminths. The wandering quarter method was used to collect soil samples from playgrounds in Nyamataro, Daraja Mbili, Nubia and Jogoo areas. Zinc sulphate floatation method was used to separate ova, cysts and larvae that were observed microscopically. Fifty five (55) out of 84 (65.5%) samples were found to be positively contaminated with canid gastrointestinal helminths (P<0.001) where 37/55 (67.27%) were contaminated with either Toxocara sp., Ancylostoma sp. or Strongyloides sp. while 18/55 (32.73%) were contaminated with mixed helminths; Toxacara sp. and Ancylostoma sp. (33.3%) or Toxacara sp. and Strongyloides sp. (66.6%). Toxocara sp. being the most prevalent helminth in all the samples collected (56.8%; P<0.001). Results show that soil samples from play grounds within the Kisii municipality were contaminated with a variety of canid gastrointestinal helminths. Therefore, it implies that the population is at risk of intermittent zoonotic epidemic outbreaks. Necessitating implementation of mass treatment and public health programmes to treat infected animals and educate the population of the possibility of acquiring saprozoonoses.
Quantitative variation in seeds, seedling growth and biomass among Acacia senegal (L) Willd. provenances in Kenya
(Wiley, 2014-10-14) Omondi, Stephen Fredrick; Githae, Eunice Wamuyu; Ochieng, John Otieno
Conventionally, local seed sources are normally believed to perform better than introduced materials. However, studies show possibility of contrary results with many species such as Acacia senegal. The species is an economically and ecologically important tree of arid and semi-arid lands of sub-Saharan Africa. It produces gum arabic, used in land reclamation and agroforestry production. The species is however underutilized in Kenya due to lack of information on growth performance of different seed sources. Glasshouse provenance trial using seeds and soils from seven provenances in Kenya were used to evaluate interactions between seed sources and soils on growth and biomass. Seedling growth was assessed for 12 weeks in a randomized complete block design. Seed length, width, thickness and weight were measured. Seedlings height, root collar diameter, root dry weight, shoot dry weight and biomass were assessed and data subjected to univariate and multivariate analyses. No significant interaction between seed provenance and soils were evident; however, some provenances performed better across all the soils. Significant heritability and relationship between growth and environmental factors are reported. Overall, Ntumburi and Ngarendare provenances showed superior growth and plasticity. These provenances can be used tentatively as seed sources; however, field trials are recommended.
Separation and attribution of impacts of changes in land use and climate on hydrological processes
(Springer Nature, 2023-01-17) Polong, Francis; Deng, Khidir; Pham, Quoc Bao; Linh, Nguyen Thi Thuy; Abba, S. I.; Ahmed, Ali Najah; Anh, Duong Tran; Khedher, Khaled Mohamed; El-Shafie, Ahmed
This study aims to assess, compare, and attribute the effects due to separate and combined land use/land cover (LULC) and climate changes on hydrological processes in a tropical catchment. The Soil and Water Assessment Tool (SWAT) model is set up and calibrated for a small contributing sub-basin of the Tana River Basin (TRB) in Kenya. The model is then applied to simulate the hydrological components (i.e., streamflow (FLOW), evapotranspiration (ET), soil water (SW), and water yield (WYLD)) for different combinations of LULC and climate scenarios. Land use data generated from Land Satellite 5 Thematic Mapper (Landsat 5TM) images for two different periods (1987 and 2011) and satellite-based precipitation data from the African Rainfall Climatology version 2 (ARC2) dataset are utilized as inputs to the SWAT model. The Nash–Sutcliffe model efficiency (NSE), coefficient of determination (R2), percent bias (PBIAS), and the ratio of root mean square error to the standard deviation (RSR) for daily streamflow were 0.73, 0.76, 3.16%, and 0.51 in calibration period, respectively, and 0.45, 0.54, 12.53%, and 0.79 in validation period, respectively, suggesting that the model performed relatively good. An analysis of the LULC data for the catchment showed that there was an increase in agricultural, grassland, and forested land with a concomitant decrease in woodland and shrubland. Simulation results revealed that change in climate had a more significant effect on the simulated parameters than the change in LULC. It is shown that changes in LULC only had very minor effects in the simulated parameters. The monthly mean FLOW and WYLD decreased by 0.02% and 0.11%, respectively, while ET and SW increased by a monthly mean of 0.2% and 2.2%. Varying the catchment climate and holding the land use constant reduced FLOW, ET, SW, and WYLD by an average monthly mean of 43.2%, 21%, 13%, and 70%, respectively, indicating that climate changes have more significant effects on the catchment hydrological processes than changes in LULC. Thus, it is necessary to evaluate and identify the isolated and combined effects of LULC and climatic changes when assessing impacts on the TRB’s hydrological processes.
Separation and attribution of impacts of changes in land use and climate on hydrological processes | Theoretical and Applied Climatology
(Springer Link, 2023-01-17) Francis Polong, Khidir Abdalla Kwal Deng, Quoc Bao Pham.
This study aims to assess, compare, and attribute the effects due to separate and combined land use/land cover (LULC) and climate changes on hydrological processes in a tropical catchment. The Soil and Water Assessment Tool (SWAT) model is set up and calibrated for a small contributing sub-basin of the Tana River Basin (TRB) in Kenya. The model is then applied to simulate the hydrological components (i.e., streamflow (FLOW), evapotranspiration (ET), soil water (SW), and water yield (WYLD)) for different combinations of LULC and climate scenarios. Land use data generated from Land Satellite 5 Thematic Mapper (Landsat 5TM) images for two different periods (1987 and 2011) and satellite-based precipitation data from the African Rainfall Climatology version 2 (ARC2) dataset are utilized as inputs to the SWAT model. The Nash–Sutcliffe model efficiency (NSE), coefficient of determination (R2), percent bias (PBIAS), and the ratio of root mean square error to the standard deviation (RSR) for daily streamflow were 0.73, 0.76, 3.16%, and 0.51 in calibration period, respectively, and 0.45, 0.54, 12.53%, and 0.79 in validation period, respectively, suggesting that the model performed relatively good. An analysis of the LULC data for the catchment showed that there was an increase in agricultural, grassland, and forested land with a concomitant decrease in woodland and shrubland. Simulation results revealed that change in climate had a more significant effect on the simulated parameters than the change in LULC. It is shown that changes in LULC only had very minor effects in the simulated parameters. The monthly mean FLOW and WYLD decreased by 0.02% and 0.11%, respectively, while ET and SW increased by a monthly mean of 0.2% and 2.2%. Varying the catchment climate and holding the land use constant reduced FLOW, ET, SW, and WYLD by an average monthly mean of 43.2%, 21%, 13%, and 70%, respectively, indicating that climate changes have more significant effects on the catchment hydrological processes than changes in LULC. Thus, it is necessary to evaluate and identify the isolated and combined effects of LULC and climatic changes when assessing impacts on the TRB’s hydrological processes.
Status of Opuntia invasions in the arid and semi-arid lands of Kenya.
(CABI Reviews, 2018) Githae, E. W.
Invasive alien species (IAS) are among the leading threats to biodiversity, food security and human well-being. Opuntia (prickly pear cactus) is one of the most widespread and naturalized in the arid and semi-arid areas of Kenya, with extreme effects on rural livelihoods and the environment. However, comprehensive information on the status of invasion in the country is lacking, which is crucial for developing strategies for prevention and management. This paper, therefore, provides an overview of the interacting factors that influence its invasion in Kenya in terms of species diversity, pathways of introduction, negative impacts and the effectiveness of regulations and control measures. Seven invasive species of Opuntia are present in the country with the most abundant (O. stricta) being under biocontrol trial. These species have the same habitat preferences, physiological traits, negative impacts, introduction pathways and management options. Invasion is mainly attributed to changes in land use and consequent land degradation. Introduction pathways are largely intentional for ornamental purposes but unintentional at a local scale through escape from gardens and natural dispersal. The most applied methods of managing Opuntia are mechanical and chemical methods that are unsustainable and labour-intensive at large scale. Effective policies are therefore needed to prevent an increase in the significant negative impacts caused by IAS including those that have a limited distribution.

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