Most of Africa’s wildlife lives outside of national parks and reserves, on a land that they share with livestock. Conversely, most African livestock share their land with wildlife. The Kenya Long-term Exclosure Experiment (KLEE) was established in 1995 by Dr. Truman Young of the University of California at Davis to better understand the interactions between wildlife and cattle and their individual and combined effects on their shared savanna ecosystem. The KLEE experiment consists of 18 four-hectare plots in three replicate blocks. In each block, we use different semi-permeable barriers to exclude six combinations of cattle (C), wildlife (W), and mega-herbivores (M: elephants and giraffes). We also have embedded in KLEE multiple additional experiments that manipulate fire, overgrazing, soil fertility, rainfall, and tree density. In particular, a decade ago Drs. Duncan Kimuyu and Ryan Sensenig initiated an ambitious experimental protocol involving both annual and three-year burn regimes.
Using KLEE, we have been able to unravel complex and fascinating relationships between livestock, wildlife, fire, drought and the rich biodiversity in Laikipia. We have demonstrated that interactions between livestock and wildlife are often negative, but also include multiple positive relationships. For example, although cattle and wildlife do compete during the dry periods, both cattle and wildlife can benefit from each other’s presence during wet periods. Surprisingly, elephants appear to reduce many of the negative effects of cattle on wildlife and soil properties, in part by reducing forage uptake by cattle. Our research was the first to demonstrate how abandoned cattle corrals (bomas) produce long-lived ecosystem “hotspots” of increased quality and productivity of forage attractive to wildlife. This knowledge is changing livestock management in Laikipia by contributing to greater use of mobile bomas and restoration of degraded habitat patches.
We have documented myriad additional ecological cascades, including the separate and combined effects of wildlife, cattle, fire and drought on each other and on soils, microbes, grasses, forbs, trees and shrubs, ecosystem productivity, invertebrates (spiders, termites, butterflies, ants, mosquitos), rodents, birds, and snakes. In particular, the removal of either cattle or wildlife leads to large increases in the population of rodents, along with their disease vectors (ticks and fleas) and many human and livestock pathogens. (see https://tpyoung.ucdavis.edu/kleepubs).
As KLEE enters its fourth decade, we are addressing stability and resilience of ecological systems, and the strong context dependence of ecological responses. We want to understand:
- How does the stability/resilience of this savanna ecosystem change under multiple experimental and natural stressors over multiple decades?
- Is there a discernable structure underlying the interactions among these multiple ecosystem responses to multiple stressors?
Understanding both the long-term and short-term responses of ecosystems to multiple stressors is critical to predicting and preparing for future ecological conditions and management decisions. Our multi-layered experimental design, carried out over a long and ecologically relevant time scale, is revealing new patterns and processes in ecological resilience. Our unique combination of multiple stressors and multiple response variables is producing new insights insights into the mutually reinforcing mechanisms underlying ecosystem stability and resilience. One particular exciting new project is examining the interactive roles of fire and herbivory on carbon sequestration in savannas (see https://mpala.org/interactive-effects-of-fire-and-grazing-on-carbon-accumulation-in-grasslands/).
KLEE includes many Kenyan and U.S. collaborators, including Duncan Kimuyu, Truman Young, Wilfred Odadi, Ryan Sensenig, Mary Ngugi Waithera, Robert Ang’ila, Tyler Coverdale, and Amy Wolf. Our past and present research assistants, Mathew Namoni, Jackson Ekadeli, Julius Lengais, Fredrick Erii, John Lochkuya, and Stephen Ekale have contributed immensely to the success of this project. The KLEE project has supported 30 masters and doctoral theses, more than half of them with Kenyan scientists. With 200 peer-reviewed and outreach publications, KLEE has become the most productive field experiment ever carried out in Africa (see https://tpyoung.ucdavis.edu/kleepubs).
Universities and Organizations: University of California-Davis, Karatina University, Egerton University, University of Notre Dame, University of Texas
Primary Investigators: Dr. Truman Young (University of California-Davis), Dr. Duncan Kimuyu (Karatina University), Dr. Ryan Sensenig & Dr. Tyler Coverdale (University of Notre Dame), Dr. Wilfred Odadi (Egerton University), Dr. Amy Wolf (University of Texas)
Project Director: Dr. Duncan Kimuyu