The Elephant Dilemma: A Long-term Perspective on the Management of African Savannas - Biodiversity Conservation and Environmental Change - page 16

Depth
cm

K-4

100 Woodland

Phase

200

10

300

K-3

Grassland
Phase

400

471

500

20

600

711

700

Woodland
Phase

30

800

K-2

900

40 1000

1100

50

1200

Grassland
Phase

K-1

1295

1300

60

0102030405060708090 0

cm 2 cm 3

0.5 1 1. 5 2 2.5 3 3.5

%

Figure 2.1 (a) Woodland-grassland hypothesis, which suggests stable cycles between tree abundance
and elephant populations (Caughley 1976). (b) Pollen diagram from Kanderi Swamp, Tsavo National
Park, Kenya, showing evidence of woodland and grassland phases. The data confirm that tree cover can
rebound from long periods of very low densities (Gillson 2004b).