Succession and management - Ecological Applications: Toward a Sustainable World - page 223

(c)

100
80
60
40
20
0

27 widespread species

(a)

40

35

30

0369121518 21 Co Id

25

(d)

(f)

100
80
60
40
20
0

9 east coast species

100

20

036912151821CoId

75

(b)

110
100
90
80
70
60
50
40
30

50

25

0369121518 21 Co Id

0

(e)

0369 2 51821
Stand age (years)

100
80
60
40
20
0

19 Maputaland species

036912151821CoId

0369121518 21 Co Id

Stands

SD)
during succession to dune forest in South Africa after cessation of sand mining (0, 3, 6, 9, 12, 15, 18 and 21 years later)
compared to undisturbed, mature sand dune coastal (Co) and inland (Id) forests. (c) The most widespread of dung beetle
species, with their excellent powers of dispersal, show no particular pattern with succession and (d) neither do species
characteristic of the wider local area (e a st coast species), but the most restricted and local Maputaland species (e) are
increasingly represented as succession proceeds. (f ) The dung beetle communities become increasingly similar to mature
dune forest as succession proceeds, and this is particularly the case for shade-specialist species (open circles); closed circles
represent all species combined. (After Davis et al., 2002, 2003.)

Fig. 8.6 Changes to (a) mean air temperature and (b) mean humidity (daytime, closed circles; night, open squares +

The average effects of nurse shrubs were calculated for different categories of
target woody plants, different categories of nurse plants and different abiotic condi-
tions (Figure 8.7). The benefi t provided by nurse shrubs was evident for the survival
of seedlings of evergreen and deciduous trees, particularly oak trees ( Quercus spp.)
and Acer opalus , refl ecting the late-successional status of these species and their
requirement for shade. However, mid-successional woody shrubs such as Rhamnus
alternus and Crataegus monogyna also benefi ted signifi cantly. On the other hand,
the shade-intolerant montane pines were not facilitated by the presence of nurse
plants (Figure 8.7a). Among the nurse plants, legumes provided the strongest facili-
tation for woody species. Legumes have root nodules containing bacteria that fi x
atmospheric nitrogen into a form that plants can use: in this way legumes enhance
soil nutrient status in these nitrogen-limited soils (Figure 8.7b). The legumes, and