ELEPHANT DECLINE IN LAKE-MANYARA-NATIONAL-PARK, TANZANIA

The population of African elephant (Loxodonta africana (Blumenbach)) i n Lake Manyara National Park, northern Tanzania, declined from about 5 00 individuals in 1984, to about 150 in 1988 due to poaching (mortalit y rate about 60% p.a.). In 1991 the population had declined further to about 60 individuals (mortality rate about 30% p.a.). In 1984 and 199 1 road counts in the park were conducted. In 1984 a total distance of 2705 km was covered which yielded sightings of 777 elephant groups. In 1991 this distance was 5486 km and only 53 groups were observed. In b oth years an average elephant was seen in a group of seven individuals . Poaching pressure, apparently, had no effect on average group sizes. Group size changes with season, both in 1984 and 1991. The smallest g roups were observed during the dry season when Acacia tortilis pods pr ovided a defendable resource. In 1984, elephant occurred significantly more than expected in groups of five-nine individuals and less than e xpected in groups of one or two individuals or in groups larger than 1 6. This has been interpreted as a confirmation of the family structure of elephant as reported in other studies. In 1991, elephant group siz es were distributed according to a model of random association of indi viduals, indicative of destruction of the social framework by poaching .