Introduction: Ageratum houstonianum is an herbaceous, drought-tolerant plant also known as Blue billygoat weed. It grows well in drained soil and shaded areas. Soil moisture and porosity are two abiotic factors that affect the abundance and distribution of A. houstonianum. An ideal condition for plants to grow includes a greater amount of soil moisture and porosity. Higher porosity would mean that there is a greater number of pores, which would result in more significant plant nutrients because of its ability to retain more water. The purpose of this research was to see how soil moisture and porosity based on the gradient with regards to distance from the tree impact the abundance and distribution of A. houstonianum.

Materials and Methods: The belt transect method was used to test the soil moisture and porosity, and three belts with four quadrants in each were formed. For each of the belts, the first two quadrants closer to the tree were called zone 1, and the last two quadrants were labeled as zone 2. We hypothesized that there was an increase in abundance and distribution further away from the tree. Abundance was calculated by finding the density of the total number of species over each quadrant area. Soil samples were collected to test the soil moisture and porosity. Paired two-sample t-tests and ANOVA single factor tests were performed.

Results and Conclusion: The t-tests showed a difference between the relationship of abundance/moisture, abundance/porosity, and moisture/porosity. The ANOVA test compared the means of density/moisture/porosity between zone 1 and 2 to see if they were statistically different from each other. Based on the results, there was a decrease in the density as the distance from the tree increased. Soil moisture and porosity also decreased as the distance from the tree increased, which rejected the hypothesis. Closer to the tree, there was an increase in moisture, density, and porosity, which led to the abundance of A. houstonianum species because the ideal conditions were met.