Integrating multispectral imagery, airborne lidar and field inventory data for invasive species management in southern coastal areas of USA.
Type of DegreeMaster's Thesis
Forestry and Wildlife Science
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Invasive plant species have imposed severe threats to native ecosystems, worldwide. Among the well-established species, Chinese tallow (Triadica sebifera) and Chinese privet (Ligustrum sinense) are among the worst invasive plant species of the southern United States. Therefore, it is crucial to understand their distribution and spread mechanism for management implications. The objectives of this work were to: (1) develop a spatially explicit distribution map of invasive Triadica sebifera and Ligustrum sinense using NAIP imagery and airborne lidar in coastal Alabama, USA, and (2) assess the pattern and factors supporting spread of Chinese tallow in coastal plant community. For the first objective, free and publicly available remote sensing data i.e., National Agriculture Imagery Program (NAIP) imagery and airborne light detection and ranging (lidar) data, were used to compare three image classification methods, representing unsupervised, supervised and machine learning techniques, respectively: (1) Iterative Self-Organizing Data Analysis Technique (ISODATA) clustering, (2) Maximum Likelihood, and (3) Random Forest (RF). The maximum overall accuracy of 98.62% was obtained using the RF model with lidar-derived products and NAIP imagery. For the second objective, two sampling approaches, simple random sampling and line transect sampling were used to conduct a field inventory in May 2021. Data analysis was carried out using statistical approaches such as correlation analysis and Zero Inflated Negative Binomial (ZINB) regression analysis. The results of the study showed that the community structure influences distribution of Chinese tallow. Additionally, factors such as soil moisture, elevation, proximity to roads, forest type, use of overstory trees by birds, and overland water flow events dispersing seeds have a major impact on the prevalence of Chinese tallow invasion. The outcomes from this study include an initial baseline inventory of critical invasive species in the region that supports larger-scale mapping and the factors that contribute to the spread of Chinese tallow. These findings are expected to aid in Chinese tallow management decisions in future and facilitate development of a framework for monitoring invasives.