Precipitation and Greenness in Pastoral Lands of East Turkana, Kenya

Authors

Paul Akpejeluh, University of Nebraska-LincolnFollow

First Advisor

Daniel R. Uden

Date of this Version

11-2023

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Natural Resource Sciences

Under the supervision of Professor Daniel R. Uden

Lincoln, Nebraska, November 2023

Comments

Copyright 2023, Paul Akpejeluh

Abstract

Pastoralism has long supported livelihoods and provided essential ecosystem services in landscapes of East Africa. Vegetation productivity is central to the functioning of pastoral systems but may be affected by changes in climate and landuse. Vegetation monitoring is important for understanding the effects of global change in pastoral lands; however, it can be time and resource intensive. Remote sensing provides opportunities for efficient multi-scale monitoring of vegetation and climatic drivers. In this thesis, I explore the utility of satellite and UAV remote sensing for monitoring vegetation and precipitation trends and relationships in the East of Lake Turkana Region of northern Kenya. In Chapter 1, I examine regional greenness and precipitation time series at monthly, seasonal, and annual temporal resolutions, as well as relationships between greenness and precipitation from 2000 to 2022. I found evidence of long-term precipitation–greenness coupling at monthly and annual temporal resolutions. There were no trends in monthly or annual regional precipitation, while NDVI significantly increased at monthly temporal resolution but did not exhibit a significant trend at annual temporal resolution. Traditional pastoral practices, such as use of livestock corrals (bomas), also influence local vegetation composition and abundance. In chapter two, I use satellite and unmanned aerial vehicle (UAV) remote sensing data to monitor greenness in and around abandoned boma settlements at seasonal and annual temporal resolutions. Results showed that mean NDVI from UAV and Sentinel-2 data varied based on seasons (dry or wet) and from boma to boma. NDVI significantly differed between bomas and non-boma sites and there was significant positive correlation between NDVI with precipitation across all bomas, with an optimum temporal lag response of one month. Collectively, my results add to the body of literature demonstrating the utility of satellite and UAV-based remote sensing data for monitoring vegetation in pastoral systems.

Advisor: Daniel R. Uden