Сборник материалов международной научной конференции студентов, магистрантов, аспирантов

K.А. Рыжко, И.А. Вашкевич

Республика Беларусь, Брест, БрГУ имени А.С. Пушкина

Научный руководитель – Н.В. Иванюк

GREVY’S ZEBRA: MAIN TREATS AND CONSERVATION

Grevy’s zebra is the largest living wild equid. It can be distinguished from the other two species of zebra by its larger ears and narrower stripes. In 1882, Menelik II, the Emperor of Abyssinia (now Ethiopia), thought the zebra was so regal that he presented one as a gift to the President of France, Jules Grévy.

In recent history, the species has undergone one of the most substantial reductions of range of any African mammal. There has been a decline in numbers since the end of the 1970s. The decline was due in part to hunters killing the animals for their skins, which were made into fashionable clothing during the 1970s and 80s.

While the species is no longer commercially hunted for its skin, numbers are continuing to decline due to competition with pastoral people and their domestic livestock, and to the long-term effects of overgrazing.

Zebras belong to the Equid (horse) family of the order Perissodactyla (odd-toed ungulates), a group of herbivores that also includes rhinoceroses and tapirs. The first horses appeared in the early Eocene of North America, around 56 million years ago. They were the size of small dogs and had several toes on each foot, unlike the single hoofs of modern horses. These early horses closely resembled the ancestors of rhinos and tapirs. They were browsers, and lived in forests and savannas. During the Miocene climate change led to a reduction in the amount of forest cover and an increase in grassland. This was a time of great evolutionary change for the early equids, with many groups evolving larger body sizes and adapting to a grazing lifestyle. Horse diversity peaked in the mid-Miocene, with more than a dozen different genera evolving of many different sizes.

Since that time horse diversity has gradually decreased, with all forms becoming extinct with the exception of the modern horse genus, Equus. This genus first evolved during the North American Pliocene (4.5 to 1.8 million years ago). Members of this successful genus spread throughout Asia, Europe, Africa and South America during the first major glaciations of the late Pliocene (2.6 mya). However, in the late Pleistocene (around 12,000 years ago) a set of devastating extinctions killed off the horses, along with most other large mammals in North and South America. Today, wild horses are found only in parts of Africa and Asia.

After being inside their mothers for 13 months, Grevy’s zebra foals are born. Births are usually timed with the onset of rains with peaks observed in May/June (long rains) and November/December (short rains).

The species is predominantly a grazer, although it will also browse on shrubs and trees. It can eat tough, fibrous grasses that are inedible to cattle and some other ungulates(hoofed mammals). Lifespan in the wild is not known, although captive individuals can live into their late twenties.

The species used to occur throughout northern Kenya, Somalia and Ethiopia, to the coast of Eritrea and Djibouti. Today, northern Kenya is the species’ stronghold. There are three small and isolated populations in Ethiopia, and there may be a few individuals surviving in the Sudan.

Towards the end of the 1970s, the total wild population of Grevy’s zebra was estimated to be approximately 15,000 animals. By 2002, some 3,000–3,500 animals were thought to survive (representing a 75 percent decline in numbers). In Ethiopia the situation is even worse with a 93 percent decline in numbers (from an estimated 1,500 animals in 1980 to 110 in 2003). The most recent estimates of 1700-2000 animals suggest an overall population decline of 87 percent.

The main threats to the species today are habitat loss and degradation. This is primarily due to overgrazing by domestic livestock, which alters vegetation structure and reduces the availability of forage. Access to water is limited, particularly during the dry season, due to the effect of irrigation schemes in highland areas and the exclusion of wildlife from water sources (this has occurred as a result of pastoralists becoming more sedentary around permanent and seasonal water sources). The animals must therefore compete with pastoral people and their livestock for water as well as food. The increasingly long distances that zebras now have to travel between suitable grazing areas and water sources are thought to be having a detrimental effect on breeding rates and infant survival. Poorly regulated ecotourism (e.g. off-road driving) may disturb the animals and also affect breeding, even within protected areas.

The species is currently listed under Appendix I of CITES, and is legally protected in Ethiopia. However, the continuing decline here suggests that this nominal protection has not been effective. The species is not legally protected in Kenya, although it has been covered by a hunting ban since 1977. The Kenya Wildlife Service (KWS) is currently working to upgrade the species’ status to Protected in Kenya.

Protected areas form less than 0.5 percent of the species’ range. In Ethiopia, it is found in three nominally protected areas: Alledeghi Wildlife Reserve, Borana Controlled Hunting Area, and Chalbi Wildlife Reserve (Chew Bahir). However, there is no effective protection of wildlife in these areas. The species is found in a number of protected areas in Kenya, including the Buffalo Springs, Samburu, and Shaba National Reserve complex. The largest protected population which comprises 22% of all wild Grevy’s occurs in the Lewa Wildlife Conservancy and is a critical birthing area and an important dry season refuge. Other protected areas in Kenya appear to be largely ineffective. For example, in Sibiloi National Park, Grevy’s zebras are now uncommon, whilst Losai National Reserve is not functional as a protected area.

Conservation initiatives for the species on Laikipia Plateau in Kenya, and particularly on the Lewa Wildlife Conservancy have led to increase in numbers in both areas. In addition, many of the communities in this region have established conservancies for wildlife conservation in which management caters for both wildlife and pastoralism. There is now a network of conservancies stretching from Lewa in the south to Laisamis in the north. Conservancies have been established with support from the Northern Rangelands Trust.

1. 
   Wilson, D. E. Mammal Species of the World / D. E. Wilson, D. M. Reeder. – New York : Johns Hopkins University Press, 2005. – P. 631–632.
   
2. 
   Is the endangered Grevy’s zebra threatened by hybridization? / J. E. Cordingley [et. al.] // Animal Conservation. – No. 12 (6). – P. 505–13.
   

Зебра Греви – вид млекопитающих из семейства лошадиных (Perissodactyla), получивший своё название в честь французского президента Жюля Греви, которому в 1880-х был подарен один экземпляр этого животного правительством Абиссинии. Местами обитания зебры Греви являются засушливые саванны Восточной Африки в Кении, Эфиопии и Сомали. Вид считается находящимся под угрозой исчезновения и защищён Конвенцией по международной торговле вымирающими видами дикой фауны и флоры (CITES).