Population density of elephants and other key large herbivores in the Amboseli ecosystem of Kenya in relation to droughts

Abstract

Kenya/Tanzania borderland is a critical area for conservation of biodiversity. This study was done to establish the effects of 2007 and 2009 droughts through aerial counts. Findings indicate that large mammal population collapsed, but some species crashed more than others. Total large mammal density declined over three times (−207.43%), recovering modestly (+41.59%) between 2010 and 2013. Over that time, the most abundant species was zebra (10,466.3 ± 2860.5 animals), followed by wildebeest (8921.0 ± 4897.9), Grant's gazelle (3447.0 ± 303.7), Maasai giraffe (1381.3 ± 132.7), African elephant (990.67 ± 12.60), eland (544.0 ± 311.4), Thomson's gazelle (495.3 ± 232.3), buffalo (331.3 ± 128.8) and impala (354.3 ± 61.0). The species affected most by drought was lesser kudu, followed by African buffalo, Maasai giraffe, kongoni, common eland, common wildebeest, common zebra, Grant's gazelle, gerenuk, impala, African elephant, Thomson's gazelle and fringe - eared Oryx respectively. Further, large mammal species numbers were dependent on location (χ2 = 13,647.35, df = 15, p < 0.001), with numbers being higher near protected areas. Animals with low numbers, specific diets, water - dependent and limited range were most affected by the drought. This provides a baseline for future comparisons and also future effects of droughts.