Distribution of parthenium weed (Parthenium hysterophorus) in Nakuru County, Kenya

Abstract

This study sought to map the distribution of parthenium weed in Nakuru County. Field surveys were conducted in September 2021 using the quadrat method, whereby the road stretch between Naivasha junction and Kibunja was used as the main transect. Data on the presence or absence of parthenium weed was recorded, and the geographical coordinates were taken using a hand-held GPS receiver and loaded into ArcGIS 9.3 computer software for the development of a parthenium-distribution map. Data were analysed using IBM SPSS V. 28 statistical tool (SPSS Inc., Chicago, IL). Correlation analysis (at a 5% significance level) was used to show the relationship between the presence of parthenium weed and elevation, while descriptive analyses were used to determine the proportion of invaded quadrats. The results of this study revealed that parthenium weed was widespread in Nakuru County, with 79.2% of quadrats sampled invaded. The majority of parthenium weed invasions were reported in low-altitude regions (<1999 M ASL), especially those between Naivasha and Nakuru (r = -0.507, P < 0.001). This study showed that Nakuru County is threatened by parthenium weed due to its vast distribution. Therefore, the County Government of Nakuru should prioritise parthenium weed management to avert further spread.