The invasion of introduced species into nature reserves in tropical savannas and dry woodlands

Macdonald, I. A. W.; Frame, George W.

doi:10.1016/0006-3207(88)90005-5

Cited by 68 publications

(58 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is a medium-sized shrub that reaches a height of 1.5-2 m. In its naturalised ranges the species forms dense impenetrable monospecific stands that out-shade most native vegetation (Goodall and Erasmus 1996). In the savanna biome of South Africa the species grows in a variety of vegetation types, including grassland, but it prefers woodland habitat and forest margins and is often found along rivers (Macdonald and Frame 1988;Goodall and Zacharias 2002;Foxcroft et al 2010). In closedcanopy woodlands and forest margins it becomes a large scrambler that grows into the tree canopy, with light and pithy stems that dry quickly and burn easily (Macdonald and Frame 1988).…”

Section: Study Speciesmentioning

confidence: 99%

“…In the savanna biome of South Africa the species grows in a variety of vegetation types, including grassland, but it prefers woodland habitat and forest margins and is often found along rivers (Macdonald and Frame 1988;Goodall and Zacharias 2002;Foxcroft et al 2010). In closedcanopy woodlands and forest margins it becomes a large scrambler that grows into the tree canopy, with light and pithy stems that dry quickly and burn easily (Macdonald and Frame 1988). Even after severe disturbances, such as cutting, the species resprouts rapidly from remaining green stems and/or from the base (Devendra et al 1998).…”

Section: Study Speciesmentioning

confidence: 99%

“…Exotic plants not only invade landscapes that are heavily modified by humans, but many protected areas are facing similar threats (Macdonald and Frame 1988;Usher et al 1988). According to global change scenarios, savannas are among the ecosystems most vulnerable to biotic invasions (Sala et al 2000).…”

Section: Introductionmentioning

confidence: 99%

“…The exotic scrambling shrub Chromolaena odorata, for example, is a species that has been reported to increase vertical continuity of fires in savannas, i.e. lifting grassland fires into tree canopies (Macdonald 1983;Macdonald and Frame 1988). Since C. odorata preferably invades closed woodland and forest margins, it might facilitate grassland fires into these fire-sensitive habitats that do not burn when ecotones are not invaded (Macdonald 1983;Macdonald and Frame 1988).…”

Section: Introductionmentioning

confidence: 99%

“…lifting grassland fires into tree canopies (Macdonald 1983;Macdonald and Frame 1988). Since C. odorata preferably invades closed woodland and forest margins, it might facilitate grassland fires into these fire-sensitive habitats that do not burn when ecotones are not invaded (Macdonald 1983;Macdonald and Frame 1988). Hence, understanding how woody invaders in African savannas alter the fire regime might not only hold the key to control their invasion, but also increase our insight in the potential threats of this altered fire regime to firesensitive habitats.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Managing invasions at the cost of native habitat? An experimental test of the impact of fire on the invasion of Chromolaena odorata in a South African savanna

Beest

Cromsigt

Ngobese³

et al. 2011

Biol Invasions

View full text Add to dashboard Cite

Successfully managing invasive plants in natural systems is extremely difficult. Recently however, progress has been made with an approach focused on changing ecosystem processes through the disturbance regime. We performed a large-scale (3 ha) full-factorial field experiment in densely invaded woodland in Hluhluwe-iMfolozi Park, a savanna reserve in South Africa, to study the effect of fire on the control of the pan-tropical invasive exotic shrub Chromolaena odorata in combination with the conventional method, i.e. manual clearing and herbicide application. We show how fire interacted with the conventional clearing of C. odorata and induced an intense canopy fire that caused a shift from woodland to grassland. After 2.5 years of monitoring, grasses were still dominant and re-invasion minimal. It is important to note that fire without prior clearing did not have the same effect and was not successful in reducing densities of C. odorata. An integrated control practice targeting the species with mechanical and chemical methods, while simultaneously targeting its habitat through fire, effectively controlled dense C. odorata thickets during the course of the experiment. However, this approach transformed regular surface fires into high-intensity canopy fires that are rare in savannas. We discuss how this altered fire regime may threaten native habitats, including fire-sensitive forest patches and riverine woodlands within the savanna mozaic. This is an important dilemma for managers that should not be overlooked and asks for long-term data on the impact of control programs on the native vegetation.

show abstract