ECOLOGY, CONSERVATION, AND DIVERSITY OF MAMMAL COMMUNITIES IN AN AFRICAN ECOSYSTEM RECOVERING FROM CIVIL WAR

Abstract

As we face the sixth mass extinction, understanding ecological consequences of shifting faunal communities is becoming increasingly important. Studies have shown that the loss of large-bodied mammals can have cascading effects for ecosystem function, from the breakdown of mutualisms to an increase in diseases. Yet rarely do we get the chance to watch mammal communities reassemble after mass defaunation. Parque Nacional da Gorongosa (Gorongosa National Park), Mozambique, is an ideal place to study the consequences of extinction and community reassembly. Civil war decimated its wildlife populations between 1975-1995, with >90% declines for most large mammals. In addition to the near-total extirpation of the large predator guild, megaherbivores such as elephant and buffalo experienced population collapse. A restoration effort is now underway.

These changes have had cascading effects on the park’s mesoherbivores, as well as its plant communities. Chapter 1 addresses the effects of large herbivore loss and dynamic reassembly on floodplain vegetation. Using resurveys of vegetation plots monitored before the war, a replicated herbivore exclosure experiment monitored for two years, and diet data, this dissertation describes an herbivore-induced shift in plant communities on the Lake Urema Floodplain. This change may have been induced by the “asymmetric reassembly” of the large herbivore guild, wherein one species, the waterbuck (Kobus ellipsiprymnus) has become more than twelve times more abundant than it was before the war. Chapter 2 shows that the recovery of large herbivores has had the unanticipated effect of suppressing an invasive shrub, suggesting that restoration of large mammals can help restore ecosystem function.

Finally, this dissertation addresses the smaller mammals of this ecosystem, focusing on bats. Little is known about the diversity and natural history of bats in this region. Chapter 3 discusses why this lack of knowledge is a problem, especially in light of the recent Ebola outbreaks. Chapter 4 is a guide to the bats of Gorongosa with natural history notes, which aims to lay the groundwork for future work on the interesting and diverse bat fauna of the Greater Gorongosa Ecosystem.