Bitou bush threat abatement plan. Review of the bitou bush and boneseed TAP. Exotic vines and scramblers expand Exotic vines. Asparagus weeds. Introduced grasses. Lantana collapse Lantana. Lantana plan. Life cycle Flowers appear throughout most of year. Seed banks remain viable for at least 4 years. Impacts Environmental Forms dense thickets that smother native vegetation.
Economic Some varieties are poisonous to stock. Social Thickets are impenetrable for animals, people and vehicles. How it is spread Spread mostly by people and fruit-eating birds. Prevention Find out how farmers can prevent weed spread. Find out how gardeners and outdoor enthusiasts can prevent weed spread.
Control Physical control Fire Burn regularly to reduce lantana's survival, but be aware that initial kill rates will vary. Effectiveness of burning will depend on the suitability of available fuel loads, fire intensity, temperature, relative humidity, soil moisture and season. Then re-establish pasture to provide competition to inhibit lantana seed germination. Fire is not recommended in areas such as rainforest and wooded or plantation areas, which are not fire-tolerant.
A typical fire control program could contain the following steps: exclude stock to establish a pasture fuel load burn may require a permit sow improved pastures; consult your local Biosecurity Queensland officer for advice continue to exclude stock until pasture has established and seeded burn again in summer before rain spot spray lantana regrowth when it is actively growing but less than 50cm tall.
Mechanical control Stick raking or ploughing can be effective in removing standing plants. Grubbing of small infestations for example, along fence lines can be a useful and effective way to remove plants, but is time-consuming. Repeated slashing can also reduce lantana's vigour, exhausting its stored resources and reducing its likelihood of re-shooting.
Some locations for example, very steep inclines or gullies are not suitable for mechanical control options because of the danger of overturning machinery and soil erosion. For example, while Lantana is known to compete with forestry species and reduce their productivity [52] , it can also increase the regeneration of some non-timber forest products [12]. In addition while the presence of Lantana, a bee-pollinated plant [80] , reduces pollinator load of native plants [81] , it makes a useful honey plant [82].
Lantana's toxic effects on livestock and its allelopathic effects on other plants are also well documented [47] — [50] , however, its alkaloids are also known to have anti-bacterial, anti-microbial, anti-inflammatory, anti-tumour, and anti-AIDS properties that have the potential for use in medicine [83].
In comparison with grass-covered surfaces, Lantana cover can increase water run-off and, therefore, surface soil erosion, but it has also proven useful to prevent soil erosion on barren mountain slopes and in deforested areas [84] , [85]. Interestingly, in India, many forest managers now accept Lantana as a naturalised plant that plays an important role in the functioning of ecosystems by, for example, providing cover to carnivores, food for birds as well as some wild herbivores in addition to the livelihood benefits that Lantana provides to the local communities [86].
As such, they only aim to manage or control Lantana rather than attempting to eradicate it. Thus the change in management strategy from eradication to control and acceptance of Lantana reflects not only a realisation of the futility of eliminating Lantana altogether, but also increasing cognisance of its ecosystem effects, both positive and negative. The focus of Lantana management thus far has been on its control and eradication.
As indicated by the increase in the number of reports on Lantana control in the s, substantial effort was made to control and eradicate Lantana in Australia and South Africa around this time [39] , [40].
While the emphasis in Australia was on biocontrol [41] , in South Africa mechanical removal was a preferred option [42]. Although these reports indicate substantial weed management efforts, they seem to have had little effect on the spread of Lantana [38] , [43] and it still remains a major concern in Australia, India and South Africa [22].
The rapid invasion of Lantana has even instigated legislation for its control in Australia and South Africa [26] , [87]. This legislation restricts its import and outlines rules for its eradication. Lantana species cannot be sold or distributed and landholders may be required to control these plants if they pose a threat to an environmentally significant area in Australia [88]. Similarly in South Africa, Lantana is a proclaimed noxious weed under the Weeds Act No 42, , and the owner or occupier of the property is obliged to eradicate Lantana when such a notice has been served [30].
In comparison to Australia and South Africa no such legislation exists in India, but evidence suggests that instead local communities have adapted to the presence of Lantana. For example, a whole new cottage industry has sprung up in areas where Lantana is now abundant. This includes its use in basketry; making rubbish bins, flower pots and fruit plates; thatching roofs; weaving hedges and making toys and furniture [22] , [89].
On a more industrial scale, Lantana pulp is used for making paper in India [90]. Adaptive management is an iterative, ongoing process of learning and responding to environmental conditions while acknowledging their dynamics, uncertainty, and changes over time [91]. The adaptations to Lantana in India represent both autonomous and planned attempts by human groups to innovate and diversify their livelihoods in response to the increasing abundance of Lantana.
Further investigations are currently underway in the Western Ghats to see what other adaptation pathways, including practical measures of control, are being pursued by various groups in response to Lantana. It is apparent that Lantana is an invasive plant that has adapted very well to the ecosystems it has invaded, often transforming their natural state.
Furthermore, its bioclimatic niche and therefore potential for its expansion might include much more land area in Australia, India and South Africa than it has currently invaded Fig. While legislation and management have aimed at controlling the density and spread of Lantana, there is limited evidence for success of such control measures. Furthermore, much of the recent scientific evidence suggests that invasive species are here to stay [1] , [15] , [16] , [92]. For example, a long-term data set of naturalized plant species on islands [92] demonstrates that the mean ratio of naturalized to native plant species across islands has changed steadily for nearly two centuries, indicating that these new species assemblages have created novel ecosystems.
In the future, conservationists and managers will need to grapple with the novel ecosystems that invasive species such as Lantana give rise to. In some areas, however, there will always be the need to control Lantana as it is a competitive weed, but these control measures need to be well defined and realistic.
Given that the success of the eradication and management of Lantana has been limited thus far, better tools are needed to manage Lantana, possibly including more effective biological control agents. However, where such control measures are not practical, one way forward might be to embrace this pan-global invasive species and to find ways for its adaptive management. We show that in Australia, India and South Africa, despite measures to control Lantana, its spread and invasion have continued.
We do this by developing a quantitative scale for comparison of invasion trajectories across three continents. These invasion trajectories display rapid rates of change in the s, between the two World Wars, possibly due to large-scale land use changes. Even though efforts to control Lantana peak in India in the s and in Australia and South Africa in the s, this has little effect on its invasion.
For most invasive species, quantitative data on historical drivers of spread are lacking and therefore development of such quantitative scale can provide a better handle on drivers of their spread. Our long-term view of Lantana invasion across three continents suggests that the future management of invasive species will require an adaptive management approach to their invasion.
Policymakers will need to find innovative and diverse approaches to such adaptive management whilst being prepared to embrace the novel ecosystems that invasive species create and to respond to future changes in social-ecological conditions that may evolve as a result of their presence.
Such an adaptive management response will be most effective to improve the resilience of both ecosystems and societies to the presence of invasive species. In the future, therefore, managers will be much better off finding new ways to adapt to invasive species rather than fighting a losing battle to eradicate them. This investigation of Lantana's invasion trajectory is based on extensive research of historical records.
We systematically surveyed between October and June reports in the Bodleian Libraries in Oxford published by forestry and land management departments in Australia, India and South Africa from the s until the present day. Information sources included all forestry bulletins held for each country in the Oxford libraries, all microfiche forestry resources held for each country and any other relevant forestry documents that came to light in searching through this material.
For India, forestry department reports and forest working plans held at government libraries in Bengaluru, Chennai and Nilambur were also searched in addition to all issues of Indian Forester held at Oxford libraries.
The eligibility criteria were deliberately broad in order to ensure that we included all relevant material. For Australia and South Africa, we searched reports from all regions where Lantana is reported. For India, we focused on the Nilgiris region in order to understand a regional-scale perspective of Lantana invasion and management. All reports that mentioned weeds and their control and mentioned Lantana in any capacity for example taxonomic, occurrence, control measures, status were included in the selection process.
Similarly, report on a site situated within the study area in the study countries for example, New South Wales and Queensland in Australia; Cape to Transvaal in South Africa; and Nilgiris in India were also included. A thorough search of these records was carried out to examine the narrative surrounding Lantana in each record.
Notes were made using direct quotes and paraphrasing; and any relevant citations given in reports were followed up for the verification of content. After duplicates were removed we were left with records for Australia, for India and for South Africa. Out of the reports shortlisted for quantitative analysis, a total of 53 were from Australia, 22 from India and 41 from South Africa. These reports presented spatial and temporal dimension of Lantana introduction, invasion, spread and control and were included in the quantitative analysis of the invasion trajectory Table S1A, S1B, S1C.
While the historical records may present only a partial picture of Lantana invasion and management, in the absence of any other ecological information going back to s, the historical records we used provide an important insight into the invasion, spread and management of Lantana over two centuries and across three continents. An additional bias is likely to be introduced because the records come from forestry departments, who are interested in eradication of invasive species due to their economic impacts.
The perception of forestry departments about the threat from invasive species therefore portrays only a partial picture of lantana invasion. However, in the absence of long-term historical ecological studies to verify such qualitative reports, we considered our semi-quantitative approach to be a pragmatic solution for an enhanced understanding of invasive species and their management.
To examine regions in Australia, India and South Africa that are affected by Lantana invasion, we plotted geographical co-ordinates for locations of all available reports Fig. Where only place names were available, we derived geographical co-ordinates from Google Maps. We colour-coded these point data for each decade between and the present day. The narratives of Lantana invasion included its mention as an ornamental plant, popular hedge plant, its spread as invasive; and the managers' success or failure to control it.
A scale of 1—7 was used to score records along increasing severity of Lantana invasion Fig. The qualitative narratives were scored independently by two of the authors EB and TT to ensure that there is consistency in scoring.
When scoring, the earliest record for each category was used to determine the timing to move up the scale. Further up the scale, Lantana is considered a weed, invasive or noxious plant and is referred to as a problem.
Management intensification reflects concerted effort by government authorities to control and manage the weed. Further up the scale, management is reported effective in some areas reflecting reports of management success. The continuation of the same management strategy is categorised as a separate entity because government agencies report using the same management strategy in the broader landscape, as opposed to intensifying management further.
The final category, which reflects the spread of Lantana despite management captures reports of frustration from the government authorities that this weed is beyond control or management. The quantitative scale we devised allowed synthesis of anecdotal information reported in historical records and comparison of Lantana narratives across the three countries.
Where judgements differed, the two authors conferred their score before including it in the quantitative scale.
Based on this quantitative scale of Lantana invasion, we calculated rate of change per year Fig. A comparison of the rates of change allowed identification of time periods that coincided with rapid spread of Lantana. To compare effort spent on controlling Lantana across the three countries, we examined the variety of methods reported for Lantana management.
These methods were categorised into five classes: fire, mechanical, chemical, biocontrol and combination of all methods. We calculated percentage of total reports in each decade that mentioned each of these methods Fig.
To identify a potential bioclimatic envelop for Lantana, we used point data for Lantana camara and synonyms in Global Biodiversity Information Facility [94] and developed a global niche model for Lantana with automated openModeller algorithm, which uses WorldClim climate layers [95].
For each given climate variable the algorithm finds the minimum and maximum value at all sites of occurrence. Historical records of Lantana. Add Image.
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