Why Elephants Roam
Abstract of dissertation to obtain the doctor’s degree at the University of Twente,on the authority of the Rector Magnificus, prof.dr. H. Brinksma, on account of the decision of the graduation committee, to be publicly defended on Wednesday 19 May 2010 at 13.15 hrs by Shadrack Mumo Ngene.
The expansion of human activities due to the increase in human population outside protected areas is reducing the range of elephant. This range reduction occurs when elephant habitats are cleared for more farms and settlements. This causes fragmentation of the elephant range, which changes the elephant’ distribution, movement patterns, intensity of occupancy, and speed of movement. Past studies on elephant distribution, movement, and intensity of occupancy in areas undergoing changes in land cover have been hindered by technological limitations, which meant data on elephant locations could only be collected during the day. However, the development of satellite-linked geographical positioning systems, allows for continuous collection of data. This way, GIS and remote sensing can be used to understand the ecology of elephant movement, as well as facilitate development of a conservation strategy for the elephant.
The objectives of this study were to use GIS and remote sensing to identify the factors that influence the distribution, intensity of occupancy, and speed of movement of Marsabit elephant; to map and describe their wet and dry season range, intensity of occupancy, and speed of movement, as well as seasonal altitudinal movement in the fragmented mosaic of forest and savanna; to research the cost of humans sharing the environment with the elephant in areas adjacent to Marsabit Protected Area.
Elephant location data were acquired from five bachelor and five female family herds equipped with satellite-linked geographical positioning system collars, and monitored from December 2005 to December 2008. Water points and settlements were mapped during a ground survey. Spatial data for elevation, slope, main roads, minor roads, vegetation cover, seasonal rivers, and soil types were acquired from the United Nations Environment Programme (UNEP) Marsabit Forest Database. Crop raiding data were collected during fieldwork by paying visits to farms raided by elephant and having discussions with farmers and the Marsabit district agricultural officer. From 18 February 2000 to 18 February 2009 MODIS NDVI 16-day composite products for the entire Marsabit region were used to assess the changes in green vegetation. Rainfall data were acquired from the meteorological department at Marsabit Meteorology Station, Kenya.
Distance from a major road, drinking water, and presence of shrubs formed the significant factors which explained 92 % of variations in the distribution of elephant. The model could predict elephant distribution with a probability of 96%. The elephant were found at high forested elevations during the dry season (NDVI = 0.2-0.3), but moved to the lowlands characterized by shrubs during the wet season (NDVI = 0.5-0.7).
Distinct dry and wet season ranges (about 260 km2 and 910 km2, respectively) were observed, with connecting corridors (a north-eastern corridor of about 90 km long and 2-7 km wide; southern corridors of about 10-20 km long and 2-3 km wide). Elephant moved faster during intermediate and wet seasons than during dry seasons. The elephant moved at a speed of more than 1 kmh-1 in corridor areas and about 0.2 to 1 kmh-1 in non-corridor areas. The elephant spent more time at the forest edge than in the forest. However, inside the forest, the intensity of elephant’ occupancy was higher around water points than in other parts of the forest. The intensity of the elephant’ occupancy was inversely related to the distance to drinking water throughout the year. During the dry season, the intensity of elephant occupancy recorded around the Marsabit forest was high, and low in the lowland shrubs. Soon after the rains started, the elephant would move to the lowland shrubs. The speed with which elephant herds moved was significantly influenced by the distance to water resources and the major road. The water resources were interconnected by minor roads, which were used as security patrol routes just as the major road.
The roaming elephant destroyed crops in 414 farms between August 2004 and July 2005 (excluding December 2004 and April 2005 due to rains). The farmers lost KES 15,034,610 (USD 208,814) during the study period. The number of farms raided and the cost of crop raiding were high during the dry season than the wet season. Crop raiding was higher in August 2005 (KES 5,598,660; USD 77,759) than August 2004 (KES 503,960; USD 6,999.4).
Security, drinking water, and shrubs/seasonal NDVI changes were the most important factors which influenced the distribution, intensity of occupancy, and speed of movement of elephant in Marsabit. Expansion of settlements towards corridor areas needs to be controlled to avoid future obstruction of the connections between wet and dry season elephant ranges. Loss of connectivity between the highland forest and lowland shrubs could result in local extinction of the elephant in Marsabit Protected Area. It is therefore important to maintain the connections between these areas through reduction and removal of settlements along elephant dispersal and migratory routes (Chapter 8). This could be achieved through fencing of corridors (Chapter 8) and gazetting them as part of the Marsabit Protected Area.
| Curriculum Vitae Shadrack Mumo Ngene | |
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Shadrack Ngene was born on 18 July 1968 in Kitui, Kenya. He completed high school in 1988 at Machakos Boys High School, where he majored in Geography, Biology and Chemistry. In 1993, he acquired his first degree in wildlife management from Moi University, Eldoret, Kenya. In September 1993, he was awarded a government scholarship and enrolled at Moi University, Department of Wildlife Management, for a Masters Degree in wildlife management. He obtained his MSc degree in 1998 with a thesis entitled: "The predation of livestock by lions and other predators in the area adjacent to Nairobi National Park, Kenya". Between 1998 and 2000, he worked as a part-time lecturer at Jomo Kenyatta University of Agriculture and Technology, Department of Zoology, and at the University of Nairobi, Department of Zoology, where he taught undergraduate students. During the same period, he worked on contract with Kenya Wildlife Service on specific projects in Nairobi & Amboseli National Parks and Maasai Mara National Reserve. In August 2000, he joined the Kenya Wildlife Service as a research scientist in the ecological monitoring department. He was posted to Nairobi National Park as a resident scientist. In 2002, he was nominated to participate in a short course on water quality management in Japan for a period of three months. In 2003, he attended the 10th World Lake Conference, Chicago, Illinois, where he presented a paper entitled: "Pollution Loading in Lake Nakuru, Rift Valley, Kenya". This paper was awarded the Lake Kasumigaura prize by the Ibaraki Prefecture, Japan. In 2004, he was sent to the Gateway Recreation Area, New York and New Jersey on an exchange program between the Kenya Wildlife Service and the National Parks Service of the United States of America for a period of three months, where he acquired more knowledge about research and management of urban parks. In late 2004, while still at the Kenya Wildlife Service, he became the Marsabit Elephant Project Officer, a project funded by the United States Fish and Wildlife Service (USFWS). He was responsible for the overall implementation of this project. In 2005, further funding of the project was provided by the Elephant Research Fund (a European Union fund managed by the Kenya Wildlife Service) and the African Parks Conservation, The Netherlands. In 2006, he was promoted to senior scientist, Northern Conservation Area, which included Marsabit National Park and Reserve. Following the experience gained at Kenya Wildlife Service and after securing project funds, he was awarded an ITC scholarship and enrolled at ITC to pursue his PhD at the Department of Natural Resources, which resulted in this thesis. After his PhD, he will continue to work with the Kenya Wildlife Service as a senior scientist in charge of Biodiversity Research and Monitoring Activities in the Tsavo Conservation Area. He has been married to Felistus Matha since September 1993 and is father of a daughter, Faith Kalunda, and a son, Francis Muthui. |
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