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A battle lost? Report on two centuries of invasion and management of Lantana camara L. in Australia, India and South Africa.

Bhagwat SA, Breman E, Thekaekara T, Thornton TF, Willis KJ - PLoS ONE (2012)

Bottom Line: The records indicate that governments in Australia, India and South Africa have taken aggressive measures to eradicate Lantana over the last two centuries, but these efforts have been largely unsuccessful.We found that despite control measures, the invasion trajectory of Lantana has continued upwards and that post-war land-use change might have been a possible trigger for this spread.While the established paradigm is to expend available resources on attempting to eradicate invasive species, our findings suggest that in the future, conservationists will need to develop strategies for their adaptive management rather than fighting a losing battle.

View Article: PubMed Central - PubMed

Affiliation: School of Geography and the Environment, University of Oxford, Oxford, United Kingdom. shonil.bhagwat@ouce.ox.ac.uk

ABSTRACT
Recent discussion on invasive species has invigorated the debate on strategies to manage these species. Lantana camara L., a shrub native to the American tropics, has become one of the worst weeds in recorded history. In Australia, India and South Africa, Lantana has become very widespread occupying millions of hectares of land. Here, we examine historical records to reconstruct invasion and management of Lantana over two centuries and ask: Can we fight the spread of invasive species or do we need to develop strategies for their adaptive management? We carried out extensive research of historical records constituting over 75% of records on invasion and management of this species in the three countries. The records indicate that governments in Australia, India and South Africa have taken aggressive measures to eradicate Lantana over the last two centuries, but these efforts have been largely unsuccessful. We found that despite control measures, the invasion trajectory of Lantana has continued upwards and that post-war land-use change might have been a possible trigger for this spread. A large majority of studies on invasive species address timescales of less than one year; and even fewer address timescales of >10 years. An understanding of species invasions over long time-scales is of paramount importance. While archival records may give only a partial picture of the spread and management of invasive species, in the absence of any other long-term dataset on the ecology of Lantana, our study provides an important insight into its invasion, spread and management over two centuries and across three continents. While the established paradigm is to expend available resources on attempting to eradicate invasive species, our findings suggest that in the future, conservationists will need to develop strategies for their adaptive management rather than fighting a losing battle.

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Invasion trajectories of Lantana in Australia, India and South Africa.(a) Historical records of Lantana spread, control and management are scored on a scale of 1–7: (1) first introduced; (2) present, but not a problem; (3) considered weed, invasive or noxious plant; (4) management intensified; (5) management reported effective in some areas; (6) continuation of same management strategy; (7) Lantana seen to be spreading in spite of management. (b) Rate of change is calculated as increase per year in the state of invasion, measured on the seven-point scale.
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pone-0032407-g002: Invasion trajectories of Lantana in Australia, India and South Africa.(a) Historical records of Lantana spread, control and management are scored on a scale of 1–7: (1) first introduced; (2) present, but not a problem; (3) considered weed, invasive or noxious plant; (4) management intensified; (5) management reported effective in some areas; (6) continuation of same management strategy; (7) Lantana seen to be spreading in spite of management. (b) Rate of change is calculated as increase per year in the state of invasion, measured on the seven-point scale.

Mentions: A quantitative assessment of the scale of invasion of Lantana gives an insight into its invasion trajectory between 1800 and the present day. The overall trend of Lantana invasion in Australia, India and South Africa is similar showing a consistent increase throughout the time period in question (Fig. 2A). There are, however, some regional differences. The time of introduction is different across the countries, with Lantana being introduced to India shortly after 1800, to Australia shortly before 1850 and to South Africa shortly after 1850. Lantana is soon considered a ‘weed’ in historical records, but the need for its management appears to arise in India and Australia only in the 1920s, while in South Africa, management is not introduced until after the 1950s. The management of Lantana continues thereafter, but recent reports from each country indicate that this plant is spreading despite management efforts to eradicate or control it. There is a small reversal in the trend in India around 2000s, reflected by the fact that management maintains status quo and, significantly, managers no longer mention eradication of Lantana as a goal but rather only mitigative management for control of the plant such that it does not adversely affect wildlife. However, subsequent reports suggest that Lantana is continuing to spread despite such management.


A battle lost? Report on two centuries of invasion and management of Lantana camara L. in Australia, India and South Africa.

Bhagwat SA, Breman E, Thekaekara T, Thornton TF, Willis KJ - PLoS ONE (2012)

Invasion trajectories of Lantana in Australia, India and South Africa.(a) Historical records of Lantana spread, control and management are scored on a scale of 1–7: (1) first introduced; (2) present, but not a problem; (3) considered weed, invasive or noxious plant; (4) management intensified; (5) management reported effective in some areas; (6) continuation of same management strategy; (7) Lantana seen to be spreading in spite of management. (b) Rate of change is calculated as increase per year in the state of invasion, measured on the seven-point scale.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3293794&req=5

pone-0032407-g002: Invasion trajectories of Lantana in Australia, India and South Africa.(a) Historical records of Lantana spread, control and management are scored on a scale of 1–7: (1) first introduced; (2) present, but not a problem; (3) considered weed, invasive or noxious plant; (4) management intensified; (5) management reported effective in some areas; (6) continuation of same management strategy; (7) Lantana seen to be spreading in spite of management. (b) Rate of change is calculated as increase per year in the state of invasion, measured on the seven-point scale.
Mentions: A quantitative assessment of the scale of invasion of Lantana gives an insight into its invasion trajectory between 1800 and the present day. The overall trend of Lantana invasion in Australia, India and South Africa is similar showing a consistent increase throughout the time period in question (Fig. 2A). There are, however, some regional differences. The time of introduction is different across the countries, with Lantana being introduced to India shortly after 1800, to Australia shortly before 1850 and to South Africa shortly after 1850. Lantana is soon considered a ‘weed’ in historical records, but the need for its management appears to arise in India and Australia only in the 1920s, while in South Africa, management is not introduced until after the 1950s. The management of Lantana continues thereafter, but recent reports from each country indicate that this plant is spreading despite management efforts to eradicate or control it. There is a small reversal in the trend in India around 2000s, reflected by the fact that management maintains status quo and, significantly, managers no longer mention eradication of Lantana as a goal but rather only mitigative management for control of the plant such that it does not adversely affect wildlife. However, subsequent reports suggest that Lantana is continuing to spread despite such management.

Bottom Line: The records indicate that governments in Australia, India and South Africa have taken aggressive measures to eradicate Lantana over the last two centuries, but these efforts have been largely unsuccessful.We found that despite control measures, the invasion trajectory of Lantana has continued upwards and that post-war land-use change might have been a possible trigger for this spread.While the established paradigm is to expend available resources on attempting to eradicate invasive species, our findings suggest that in the future, conservationists will need to develop strategies for their adaptive management rather than fighting a losing battle.

View Article: PubMed Central - PubMed

Affiliation: School of Geography and the Environment, University of Oxford, Oxford, United Kingdom. shonil.bhagwat@ouce.ox.ac.uk

ABSTRACT
Recent discussion on invasive species has invigorated the debate on strategies to manage these species. Lantana camara L., a shrub native to the American tropics, has become one of the worst weeds in recorded history. In Australia, India and South Africa, Lantana has become very widespread occupying millions of hectares of land. Here, we examine historical records to reconstruct invasion and management of Lantana over two centuries and ask: Can we fight the spread of invasive species or do we need to develop strategies for their adaptive management? We carried out extensive research of historical records constituting over 75% of records on invasion and management of this species in the three countries. The records indicate that governments in Australia, India and South Africa have taken aggressive measures to eradicate Lantana over the last two centuries, but these efforts have been largely unsuccessful. We found that despite control measures, the invasion trajectory of Lantana has continued upwards and that post-war land-use change might have been a possible trigger for this spread. A large majority of studies on invasive species address timescales of less than one year; and even fewer address timescales of >10 years. An understanding of species invasions over long time-scales is of paramount importance. While archival records may give only a partial picture of the spread and management of invasive species, in the absence of any other long-term dataset on the ecology of Lantana, our study provides an important insight into its invasion, spread and management over two centuries and across three continents. While the established paradigm is to expend available resources on attempting to eradicate invasive species, our findings suggest that in the future, conservationists will need to develop strategies for their adaptive management rather than fighting a losing battle.

Show MeSH
Related in: MedlinePlus