Dissertation

Protected Areas, Wildlife Corridors, and Large Mammal Conservation in East Africa

Riggio, Jason Scott

2018

Overview

This dissertation assesses aspects of biodiversity conservation in East Africa from three angles: 1) protected area representation and effectiveness, 2) wildlife corridors, and 3) large mammal sensitivity to humans in savanna ecosystems. I first consider protected area representation and effectiveness across East Africa. Protected areas are the cornerstone of in situ conservation and their effective management is critical for maintaining biodiversity in the long term. East Africa contains a network of 1,776 protected areas (including 186 protected areas with IUCN management categories I through IV) covering more than 27% of its terrestrial area. However, many of these protected areas were established before the advent of modern conservation biology, and several are now threatened by land conversion fueled by rapid human population growth. Here I document the extent to which East African protected areas encompass ecoregions and endemic terrestrial vertebrate taxa and, using new land conversion data derived from high spatial resolution satellite images, I assess how they have been encroached upon by agriculture and other land use. I find that East African protected areas cover most ecoregions well (>10% threshold of ecoregion representativeness set by the Convention on Biological Diversity’s Aichi Target 11), some very well (>90% - Rwenzori-Virunga montane moorlands and East African montane moorlands), but Masai xeric grasslands and shrublands, Somali Acacia-Commiphora bushlands and thickets, and Southern Swahili coastal forests and woodlands are poorly represented. While protected areas cover the geographic distribution of most East African endemic and near-endemic terrestrial vertebrate species, they cover less than 10% of the distribution of 47 endemic species (16% of the 303 endemic species). Encouragingly, East African protected areas are largely unconverted to human use, with only 6.8% of their total area experiencing land conversion (1.6% for strict protected areas). I then aim to assess the current state of wildlife corridors across Tanzania using Wami-Mbiki Wildlife Management Area as a test case. Wildlife corridors can help maintain landscape connectivity but novel methods must be developed to assess regional structural connectivity quickly and cheaply so as to determine where expensive and time-consuming surveys of functional connectivity should occur. I use least-cost methods, the most accurate and up-to-date land conversion dataset for East Africa, and interview data on wildlife corridors, to develop a single, consistent methodology to systematically assess wildlife corridors at a national scale using Tanzania as a case study. My research aims to answer the following questions; (i) which corridors may still remain open (i.e. structurally connected) at a national scale, (ii) which have been potentially severed by anthropogenic land conversion (e.g., agriculture and settlements), (iii) where are other remaining potential wildlife corridors located, and (iv) which protected areas with lower forms of protection may act as stepping-stones linking more than one National Park and/or Game Reserve. I identify a total of 52 structural connections between protected areas that are potentially open to wildlife movement, and in so doing add 23 to those initially identified by other methods in Tanzanian Government reports. I find that the vast majority of corridors noted in earlier reports as “likely to be severed” have actually not been cut structurally (21 of 24). Nonetheless, nearly a sixth of all the wildlife corridors identified in Tanzania in 2009 have potentially been separated by land conversion, and a third now pass across lands likely to be converted to human use in the near future. My study uncovers two reserves with lower forms of protection that act as apparently crucial stepping-stones between National Parks and/or Game Reserves and therefore require far more serious conservation support. Methods used in this study are readily applicable to other nations lacking detailed data on wildlife movements and plagued by inaccurate land cover datasets. My results are the first step in identifying wildlife corridors at a regional scale and provide a springboard for ground-based follow-up conservation. Finally, I evaluate the sensitivity of the larger mammals of savanna Africa to humans. Habitat loss and overexploitation are driving differential declines in vertebrate taxa but variation in responses means it is often difficult to determine where to place conservation effort. Here I present an easy-to-use method to rank the relative sensitivities of the larger mammals of savanna Africa to human activities in order to prioritize conservation activities. I first make coarse predictions about susceptibility based on species’ intrinsic ecological traits. Next I determine actual presence of these species using transect surveys within the heavily impacted Wami-Mbiki Wildlife Management Area in Tanzania, by conducting interviews outside this protected area, and monitoring changes in populations within both of these zones. (Abstract shortened by ProQuest.)

• Publisher: ProQuest Dissertations & Theses
• Subject: Wildlife Conservation
• ISBN: 0438929942, 9780438929944