Foreword
South Africa has played an outsize role in the history of biological invasions and the
development of an invasion science to understand and mitigate their impacts.
Containing a large region with temperate climate, South Africa, beginning with
European colonisation in the seventeenth century, joined Australia, New Zealand,
many oceanic islands, and large parts of the Americas as a victim of what historian
Alfred Crosby termed “ecological imperialism, the biological expansion of Europe.”
Besieged by terrestrial, freshwater, and marine species purposely or accidentally
introduced, South Africans perhaps first perceived that such newly arrived species
could be problematic in 1713 when smallpox arrived in Cape Town, killing many
indigenous Khoikhoi, who attributed the introduction to the Dutch. European immigrants and their descendants, by and large, welcomed—indeed, deliberately introduced—many of the new additions to the biota, especially trees in the South African
ecosystems lacking forests—savanna, grassland, and fynbos. Trees provided wood,
fruit, and shelter and were an aesthetic amenity attractive to European settlers.
By the turn of the twentieth century, some of these widely established nonnative
species, especially plants, were recognised as problematic. Northern hemisphere
conifers were first recorded as invasive in 1855, European spiny burweed by 1860,
Australian blue gum by the late 1860s, and Australian acacias by the turn of the
century. This was also when the advantages of New World prickly pear as edible
fruit and fodder were finally seen by many as outweighed by their disadvantages in
destroying pasture and harming livestock. Thus began the South African attempt to
understand the biology behind these invasions and to defeat them. Biological control
projects to control both insect and plant pests were quickly initiated: the vedalia
beetle from Australia was introduced in 1892 to attack the Australian cottony
cushion scale and the American cochineal insect was released in 1913 to attack
prickly pear. In the early twentieth century, many lady beetles were also introduced
to control insect pests, but with little success. Thus began the growth of an increasingly sophisticated South African science of biological control tailoring projects to
complex problems such as limiting spread of plants that are valued in some settings
(e.g., for timber or food) but reviled when they invade other sites, such as pastures or
v
South Africa has played an outsize role in the history of biological invasions and the
development of an invasion science to understand and mitigate their impacts.
Containing a large region with temperate climate, South Africa, beginning with
European colonisation in the seventeenth century, joined Australia, New Zealand,
many oceanic islands, and large parts of the Americas as a victim of what historian
Alfred Crosby termed “ecological imperialism, the biological expansion of Europe.”
Besieged by terrestrial, freshwater, and marine species purposely or accidentally
introduced, South Africans perhaps first perceived that such newly arrived species
could be problematic in 1713 when smallpox arrived in Cape Town, killing many
indigenous Khoikhoi, who attributed the introduction to the Dutch. European immigrants and their descendants, by and large, welcomed—indeed, deliberately introduced—many of the new additions to the biota, especially trees in the South African
ecosystems lacking forests—savanna, grassland, and fynbos. Trees provided wood,
fruit, and shelter and were an aesthetic amenity attractive to European settlers.
By the turn of the twentieth century, some of these widely established nonnative
species, especially plants, were recognised as problematic. Northern hemisphere
conifers were first recorded as invasive in 1855, European spiny burweed by 1860,
Australian blue gum by the late 1860s, and Australian acacias by the turn of the
century. This was also when the advantages of New World prickly pear as edible
fruit and fodder were finally seen by many as outweighed by their disadvantages in
destroying pasture and harming livestock. Thus began the South African attempt to
understand the biology behind these invasions and to defeat them. Biological control
projects to control both insect and plant pests were quickly initiated: the vedalia
beetle from Australia was introduced in 1892 to attack the Australian cottony
cushion scale and the American cochineal insect was released in 1913 to attack
prickly pear. In the early twentieth century, many lady beetles were also introduced
to control insect pests, but with little success. Thus began the growth of an increasingly sophisticated South African science of biological control tailoring projects to
complex problems such as limiting spread of plants that are valued in some settings
(e.g., for timber or food) but reviled when they invade other sites, such as pastures or
v