Why was lantana introduced into australia

In high rainfall areas it can form impenetrable thickets that blanket entire hillsides of neglected pasture. Lantana can also send long runners out along the ground, which then shoot skywards when they find a sunny gap.

So why is lantana considered a problem? First introduced into a Sydney garden in the s it quickly spread. By the first dense stands were mapped close to the mouth of the Brisbane River. Lantana seeds are dispersed by birds and mammals and germinate readily, especially in disturbed areas. While seed viability decreases with time about a quarter will germinate after 36 months some have been found to remain viable for up to 11 years. Lantana establishes rapidly in disturbed sites at the expense of other plants, due to its fast growth rates and allelopathic effects toxicity to other plants.

Regenerating native seedlings are shaded out, as are groundcovers and grasses. Existing shrubs and small trees can be smothered and are eventually pulled down by sheer weight.

So in essence, lantana can stall the successional process of regrowing forests and dominate the understorey of disturbed forests, especially if the canopy has been opened up through activities such as logging. Combined, these impacts can lead to a reduction in biodiversity.

Lantana provides cover for some undesirable animals; feral animals such as cats, pigs, rabbits, foxes and wild dogs have all been shown to take cover in lantana thickets. Contributing to another threatening process for wildlife, lantana can promote changes in fire regimes, in some instances it can increase wildfire intensity, while in other situations it can limit the spread of fire. On grazing properties lantana is not just a problem because it competes with pasture, it is also toxic to livestock.

The economic costs of lantana to the grazing, forestry and conservation sectors are very high. So we have heard from the nay side of the debate, what about the ayes? After being brought to Australia as an ornamental garden plant in about , the weed quickly escaped domestic cultivation and within 20 years was established in the wild. Lantana was first declared noxious around and by the s it had spread over more than kilometres of the eastern Australian coastline.

It thrives in warm environments with high rainfall where the weed grows along forest edges, penetrates disturbed rainforest and invades open eucalypt woodlands and pastures. Within Australia, it has invaded more than 4 million hectares. The NSW National Parks and Wildlife Service NPWS , now part of the Office of Environment and Heritage, applies an integrated approach to manage the weed, using the regional pest management strategies and the Saving our Species program to combine different control methods to achieve the best results and minimise its impact on native plant species.

Many lantana control programs are run in conjunction with local communities and councils. When management is undertaken for biodiversity conservation, five-year site management plans are completed. The best method of control is to prevent its further spread.

To get rid of large areas of lantana you might need to use herbicides, though you could try mechanical removal. Biological control has been tried, however the controlling bugs and beetles vary in their effectiveness, partly because lantana drops its leaves when stressed, leaving the bugs with no food. If this is such a weed, then why is it growing in one of the major botanical gardens of the country?

Well, trained horticultural staff look after the gardens and watch out for its spread, but the other thing to remember is that the botanical gardens are repositories for plants. Plants like the lantana are vital in plant identification and comparison, and that is a key role of botanic gardens. Weeds in Australia. Fri pm, Rpt Sun pm. Video Player failed to load.

Play Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. 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. We also thank two anonymous reviewers for their helpful suggestions. Performed the experiments: EB TT. Browse Subject Areas? Click through the PLOS taxonomy to find articles in your field.

Abstract Recent discussion on invasive species has invigorated the debate on strategies to manage these species. Introduction Biologists, ecologists and conservationists disagree on the best way to respond to invasive species [1] — [5].

Spread of Lantana and its current status Current estimates suggest that Lantana has invaded more than 5 million ha in Australia, 13 million ha in India and 2 million ha in South Africa [17] — [20].

Efforts to eradicate Lantana Historical records indicate that the drive to eradicate Lantana demanded substantial resources and manpower throughout the 19 th and 20 th centuries. Results The spatial maps of point data on Lantana spread suggest that the early invasion is recorded around towns and cities; and it subsequently spreads into the wider countryside Fig.

Download: PPT. Figure 1. Spatial distribution of Lantana records from Australia, India and South Africa based on historical reports of its spread, management and control. Figure 2. Figure 3. Methods used for control, management and eradication of Lantana during the 20 th century.

Figure 4. Bioclimatic niche model of Lantana camara based on point data stored in the Global Biodiversity Information Facility and generated by automated openModeller algorithm. Discussion The effect of Lantana on ecosystems While native to the Americas, Lantana was brought to Europe in the 16th century and since that date it has been subjected to horticultural improvement through selection of traits and hybridisation, leading to the creation of named cultivars and variants.

Invasion trajectory and management effort Our results suggest that Lantana has continued an upward trajectory of spread and invasion in Australia, India and South Africa. Rate of change and drivers of spread Our invasion trajectories of Lantana across three continents suggest that there were episodes of rapid change. Role of Lantana in providing ecosystem function and livelihoods The rapid spread of Lantana is evident from its invasion trajectory, but does this mean that its spread has always had detrimental effects on the ecosystems and the local communities who depend on them?

From eradication to adaptive management The focus of Lantana management thus far has been on its control and eradication. Materials and Methods This investigation of Lantana's invasion trajectory is based on extensive research of historical records.

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