US-Kenya Dissertation Enhancement: Aloe Secundiflora Shrubs as Facilitators in Semi-Arid Kenyan Rangelands, and Their Potential Use in Restoration

University Of California-Davis, Davis CA

Investigators

Abstract

0218254 Stanton & King This dissertation enhancement grant supports a US graduate student, Ms. Elizabeth King, working under the direction of Professor Maureen Stanton, in the Center for Population Biology at the University of California- Davis, to conduct a study in Kenya to evaluate the facilitative effect of the succulent shrub Aloe secundiflora on a perennial grass species, Cenchrus ciliaris, in degraded, semi-arid savannas. Facilitative interactions between members of different plant species can impact the population dynamics of the interacting species and the structure of plant communities. But the relationship between a facilitator and a beneficiary species is not constant and, depending on the life history stage of the species, can even become negative at certain times and under certain conditions. Under an array of different environmental conditions, Ms. King will measure the effect of transplanted aloe shrubs on each life history stage of the beneficiary grass in order to project the population-level consequences of the presence of the transplanted aloe shrubs. She will address the following questions. How does the interaction vector vary under a spectrum of possible environmental conditions? How does the interaction vector vary depending on the life history stage of the beneficiary? How do indirect effects of additional species in the plant community impact the interaction vector for a focal beneficiary species? When stage-specific fitness measurements are used in demographic models, how does the presence of a facilitator affect the projected population growth rate of the beneficiary? The results will be used to evaluate the potential impact of the use of these transplanted succulent shrubs as a means to enhance the recovery of grasses in overgrazed dry savannas. Dr. Joshua Muasya and Ms. Emily Wabuyele at the National Museums of Kenya will provide guidance on this project to Ms. King. The results of this study are expected to add to the current knowledge on the interactions of facilitator plants with a beneficiary species. It will also contribute valuable information to resource managers and policy makers involved in curtailing environmental degradation and improving human welfare--problems that face arid areas in Kenya and elsewhere in the world. This project will also support an international research experience very early in the career of an outstanding graduate student. The Office of International Science and Engineering and the Division of Environmental Biology jointly support this award.