DISSERTATION RESEARCH: Indirect Regulation of Aboveground Ecological Processes by a Belowground Ecosystem Engineer

Stanford University, Stanford CA

Investigators

Abstract

When it comes to influencing the structure and function of ecosystems, not all species are created equal. ''Ecosystem engineers'' are species that regulate resource flows to other species by modifying the physical environment, but precisely how they do this remains poorly understood relative to other ecological processes. This project focuses on how a subterranean ecosystem engineer (termites, genus Odontotermes) regulates aboveground ecological processes on a wildlife-friendly commercial cattle ranch in Kenya. Using field and laboratory experiments, the project will address how, by promoting plant growth, termites indirectly control the distribution and abundance of both invertebrates and the lizard Lygodactylus keniensis (which is the most common vertebrate in this habitat). Understanding functional relationships between species in human-dominated, working rangelands is important both for the long-term protection of ecosystem integrity and for human enterprises such as cattle ranching. In many tropical rangelands, termites are what ecologists call ''keystones''- their impact on the ecosystem is so profound as to be critical in maintaining ecosystem health. This project examines how termites exert their pivotal influence and will inform a more general understanding of keystone players in ecosystems. In addition, the project will provide full-time employment to several local Kenyans and educate both local communities and American high school students about African ecology and management via a series of popular publications and lectures.