4.3.1.2 — Mammals: Terrestrial Mammals

Migratory terrestrial mammals belong to distant systematic units such as "horses" (Hippomorpha), and several groups of Ruminantia, including deer and antelopes. Grazing mammals follow the changing availability of vegetation, induced by rainfall and snow. Impressive movements of large herds are or have been observed in savannahs, steppes and tundra in North America, Asia and Africa. The record is held by arctic caribous (Rangifer tarandus granti), where yearly migration distances of more than 5,000 km have been proven by satellite telemetry (Fancy et al. 1989).

The majority of recent scientific studies concentrate on single species. There are no summarising overviews, and in particular for Asian antelopes the information is extremely scarce. For Africa, the "African Mammal Database" (Institute of Applied Ecology 1998) provides GIS-maps for most mammals. The digital maps are freely available, and those of CMS Appendix I species were integrated into the GROMS (see Figures A2.5-8, A2.10, A2.13,14). This Geo-database is an excellent example for the potential of GIS applied to animal distribution. It contains calculations of actual areas of occurrence, based on probabilistic models including habitat quality (for the gorilla, see Figure A2.14). However, it does not include temporal aspects such as seasonal changes in distribution.

Data for the "African elephant" (Loxodonta africana) listed on CMS Appendix II are summarised by the "African Elephant Database" (Barnes et al. 1998). The printed version contains detailed distribution maps based on GIS data sets. However, this high-quality data set is not distributed outside the African Elephant specialist group, and does not form part of the African Mammal Database. There are two subspecies: Loxodonta africana africana (Blumenbach 1797) and L. a. cyclotis Matschie, 1900. The latter inhabits forests, and its conservation status is probably worse than the more widely distributed L. a. africana, classified as "Endangered" by the IUCN Red List 2000 (Hilton-Taylor 2000). The forest-dwelling L. a. cyclotis is suffering from accelerating destruction of its forest habitat and forest road construction, resulting in an increased hunting pressure (Michelmore 1994).

Another forest-dwelling species is the gorilla (Gorilla gorilla). Several subspecies inhabit the western and eastern rainforest blocks (Figure A2.13,14). As outlined in the figure captions, there is a controversial nomenclatural revision of the genus Gorilla, which according to recent studies might consist of two species, the western gorillas (Gorilla gorilla) and the eastern gorillas (Gorilla beringei), each of which consists of several subspecies. In spite of this taxonomic controversy, each of the populations can be clearly defined geographically, and all except one are in urgent need of efficient conservation measures. The mountain gorilla Gorilla gorilla beringei (Matschie 1903) is listed on CMS Appendix I, due to its occurrence and movements between Rwanda, Uganda and the Democratic Republic of Congo. It is a highly endangered flagship species, and a focus for considerable national and international conservation efforts. An intense tourism helps to finance conservation, but harbours infection risks with human diseases. The "International Gorilla Conservation Programme"³⁰ runs monitoring and supervision programs in the Virunga mountains and Uganda.

The mountain gorilla’s close relatives, the Eastern and Western flatland gorillas G. g. gorilla (Savage & Wyman 1847) and G. g. graueri Matschie, 1914, are much more numerous, but have become endangered by threats to their forest habitat and hunting for meat (Figure A2.13). According to the new taxonomy, Gorilla gorilla diehli the Cross River gorilla emerges as a critically endangered subspecies, differentiated by the IUCN Red List 2000 (Hilton-Taylor 2000). Probably fewer than 150-200 of this gorilla remain in the Cameroon/Nigeria border region, in several fragmented sub-populations, and it is still hunted. Due to its occurrence between Nigeria and Cameroon, its conservation requires international cooperation, and its inclusion into CMS Appendix I should be considered.

In particular the Cross-River-Gorilla (probably an own subspecies: G. g. diehli) is critically endangered, and should be included into CMS Appendix I, due to its occurrence between Cameroon and Nigeria.

The chimpanzee Pan troglodytes (Blumenbach, 1775) is another hominid species inhabiting sub-saharan Africa. According to Baker (1978), several populations show pronounced seasonal migrations triggered by rainfall. Its conservation status is classified as "Endangered", due to similar reasons as the gorilla (Hilton-Taylor 2000). Therefore, its inclusion into Appendix II of CMS should be taken into consideration (Table 4.3)

Most migrations of the "great herds" of grazing mammals belong to the past. The African plain’s zebra (Equus quagga) has already gone extinct, and the American bison (Bison bison) was nearly exterminated by North American settlers. The African springbok (Antidorcas marsupialis) and the Russian Saiga-antilope (Saiga tatarica) experienced similar declines. An impressive description of the massive springbok migrations is given by Schreiner (1925). Today, the Mongolian gazelle Procapra gutturosa (Pallas 1777) experiences similar dramatic declines in numbers and range (Figures A2.11, A2.12). Among the most popular and still intact migration phenomena are the movements of herbivores within the Serengeti Reserve, and the herds of Wildebeest Connochaetus taurinus (Burchell 1823) are among the major attractions of Tanzanian wildlife tourism.

African antelopes are listed on CMS Appendix I, and are a focus of the convention’s conservation activities. The scattered available information has been compiled as part of the "Action Plan for the conservation and restoration of Sahelo-Saharan antelopes" (Beudels et al. 1998). Meanwhile, the oryx (Oryx dammah) is already considered to be "Extinct in the Wild" by the IUCN Red List 2000 (Hilton-Taylor 2000) the distribution shown in Figure A2.7 is already historical! At present, the largest number of animals (around 2000) can be found scattered on private game farms in Texas. All other antelopes listed by CMS face severe threats from hunting and desertification or development of their semi-desert habitat (Figures A2.5-10). Three species of Gazella spp. are already listed as "Extinct" on the IUCN Red List 2000, among them the Arabian gazelle Gazella arabica (Lichtenstein 1827). Of uncertain systematic status, it has been suggested (unsuccessfully!) in 1979 as Gazella gazella arabica for inclusion into Appendix I, because of its occasional movements between Saudi Arabia to Yemen and Democratic Yemen (BELF 1979, p. 99). Antelopes are easily bred in captivity, which must be considered as a serious alternative in the light of the evident failure of in situ conservation. Re-introduction programs have started in some countries, but they certainly depend on viable stocks, either in captivity or in the wild (see Figure A2.8 with references, for G. dama).

Movements of terrestrial mammals can easily be disrupted by fences, roads, or habitat conversion. Fences include veterinary cordon fences, farm fences and international boundary fences. The border between Mongolia and China is blocked for Asian antelopes (see Figure A2.11), and large veterinary fences in Botswana, constructed in the 1970’s and 1980’s, were responsible for the severe decline of the Kalahari wildebeest population (Connochaetes taurinus). This migration once spanned an area around 200,000 km², thereby exceeding the range of the more famous Serengeti wildebeest. The purpose of these fences was to meet EC veterinary requirements for the control of Foot and Mouth disease, dividing the country into blocks for cattle herds destined for export (Williamson, 1999).

Several mammals listed on CMS Appendix I are technical migrants, occurring within border regions. These species cross borders, even when moving within relatively small home ranges (border taxa). Among these species are Grevy’s zebra (Equus grevyi), the barbary stag (Cervus elaphus barbarus) and the South-Andean deer (Hippocamelus bisulcus).

The snow leopard (Uncia uncia) is the only terrestrial carnivore within CMS Appendices (Appendix I). But there are several more migratory carnivores, which often follow the migration of their prey (e.g. grazing mammals). Well-documented are migrations of wolf packs(Canis lupus) following white-tailed deer (Odocoileus virginianus) in Ontario, Canada (Poszig & Theberge 2000). Icebears (Ursus arctos) nomadise within huge home ranges, extending over thousands of sqkm.

Table 4.3 summarises the mentioned terrestrial mammals of unfavourable conservation status, nomadising or migrating between countries. This list could be extended considerably, if more border taxa or nomadising species would be taken into consideration.

This document should be quoted as part of the publication "Riede, K. (2001): The Global Register of Migratory Species ­ Database, GIS Maps and Threat Analysis. Münster (Landwirtschaftsverlag), 400 pp." + CD

 by Klaus Riede