are more or less strongly influenced by humans with their livestock (Quezel 1977;
White 1983).
More than half of the area south of the Sahara consists of different types of
savannas (Du Toit and Cumming 1999), with broad-leaved savanna in the higher
regions and fine-leaved savanna in the lowlands.
The African savannas harbour the highest diversity of ungulate species (Du Toit
and Cumming 1999). These animals, some of which are endemics (Turpie and
Crowe 1993), control the structure of savannas by grazing and trampling.
The largest and most diverse shrubland in Africa is found in the southwest part of
the continent, the Karoo-Namib region (White 1983). Dwarf shrubs and succulents
are important components of the Karoo shrublands (White 1983).
The succulent Karoo biome is species-rich, and many species are regional
endemics (Mucina et al. 2006). The region harbours about 6356 vascular plant
species (Driver et al. 2003).
In the Cape, the heathland is known as fynbos. The species composition of the
fynbos, including coastal, arid and mountain fynbos types, can be extremely diverse
in the various regions of the Cape (Goldblatt 1978; Rebelo and Siegfried 1990), with
some of the richest species pools in the world (Kruger 1979). The fynbos of
South Africa is also a habitat for many endemic vertebrates such as the golden
mole Chrysochloris asiatica, the geometric tortoise Psammobates geometricus or
Victorin’s warbler Cryptillas victorini (Bigalke 1979).
In Madagascar, dry spiny bush can be found in the southwest part of the island
(Burga 2011). This habitat type is unique in terms of vegetation structure and species
composition (White 1983) and many of the plant species and reptiles are endemic to
the south of Madagascar (Cabanis et al. 1969). Another type of shrubland,
rupicolous shrubland, is found in rocky parts of the island. Some of the mountain
heathlands of Madagascar represent secondary vegetation units, which are the result
of anthropogenic influence and fires (Raxworthy and Nussbaum 1996).
2.3 North America
The shrubland of the Low Arctic region of North America is dominated by species
such as Betula nana, Salix glauca and Salix pulchra. These are often associated with
grasses, mosses and Ericaceae (Bliss 1979). Arctic heathlands can be found in
Alaska and Canada, where their structure and species composition are similar to
those in other parts of the Arctic; they consist mainly of Ericaceae, mosses and
lichens (Hanson 1953; Whittaker 1977).
The salt spray heathland, an endangered ecosystem type, is found in the coastal
region in the NE of the United States of America. The influence of salt reduces the
speed of succession and influences the composition of the vegetation in these
heathlands (Griffiths and Orians 2003).
Vast shrublands in the USA can be found in the semi-arid region of the western
part of the country (McArthur and Kitchen 2007). Huge areas in the west of the
Heathland, Scrub and Savanna: Overview, Recent Trends and Outlook
367
White 1983).
More than half of the area south of the Sahara consists of different types of
savannas (Du Toit and Cumming 1999), with broad-leaved savanna in the higher
regions and fine-leaved savanna in the lowlands.
The African savannas harbour the highest diversity of ungulate species (Du Toit
and Cumming 1999). These animals, some of which are endemics (Turpie and
Crowe 1993), control the structure of savannas by grazing and trampling.
The largest and most diverse shrubland in Africa is found in the southwest part of
the continent, the Karoo-Namib region (White 1983). Dwarf shrubs and succulents
are important components of the Karoo shrublands (White 1983).
The succulent Karoo biome is species-rich, and many species are regional
endemics (Mucina et al. 2006). The region harbours about 6356 vascular plant
species (Driver et al. 2003).
In the Cape, the heathland is known as fynbos. The species composition of the
fynbos, including coastal, arid and mountain fynbos types, can be extremely diverse
in the various regions of the Cape (Goldblatt 1978; Rebelo and Siegfried 1990), with
some of the richest species pools in the world (Kruger 1979). The fynbos of
South Africa is also a habitat for many endemic vertebrates such as the golden
mole Chrysochloris asiatica, the geometric tortoise Psammobates geometricus or
Victorin’s warbler Cryptillas victorini (Bigalke 1979).
In Madagascar, dry spiny bush can be found in the southwest part of the island
(Burga 2011). This habitat type is unique in terms of vegetation structure and species
composition (White 1983) and many of the plant species and reptiles are endemic to
the south of Madagascar (Cabanis et al. 1969). Another type of shrubland,
rupicolous shrubland, is found in rocky parts of the island. Some of the mountain
heathlands of Madagascar represent secondary vegetation units, which are the result
of anthropogenic influence and fires (Raxworthy and Nussbaum 1996).
2.3 North America
The shrubland of the Low Arctic region of North America is dominated by species
such as Betula nana, Salix glauca and Salix pulchra. These are often associated with
grasses, mosses and Ericaceae (Bliss 1979). Arctic heathlands can be found in
Alaska and Canada, where their structure and species composition are similar to
those in other parts of the Arctic; they consist mainly of Ericaceae, mosses and
lichens (Hanson 1953; Whittaker 1977).
The salt spray heathland, an endangered ecosystem type, is found in the coastal
region in the NE of the United States of America. The influence of salt reduces the
speed of succession and influences the composition of the vegetation in these
heathlands (Griffiths and Orians 2003).
Vast shrublands in the USA can be found in the semi-arid region of the western
part of the country (McArthur and Kitchen 2007). Huge areas in the west of the
Heathland, Scrub and Savanna: Overview, Recent Trends and Outlook
367