PLANTS PLANTS BEHAVING BEHAVING

BADLYBADLYA Zero Tolerance Policy?A Zero Tolerance Policy?

Aliens are mostly from Aliens are mostly from deliberate introductionsdeliberate introductions

• in the Australian wet tropics, 51 of 53 in the Australian wet tropics, 51 of 53 environmental weeds were deliberate imports as environmental weeds were deliberate imports as mostly garden and pasture plants.mostly garden and pasture plants.

Deliberate introductions -- Deliberate introductions -- spectacular failuresspectacular failures

• between 1947 and 1985 more than 460 exotic between 1947 and 1985 more than 460 exotic pasture grasses and legumes were trialed in pasture grasses and legumes were trialed in northern Australianorthern Australia

• all 460 have now become naturalisedall 460 have now become naturalised• only 21 proved usefulonly 21 proved useful• 60 ended up becoming problem weeds, including 60 ended up becoming problem weeds, including

20 of the 21 useful species20 of the 21 useful species

The rate of naturalisation is The rate of naturalisation is increasingincreasing

• Despite supposedly knowing better and with better Despite supposedly knowing better and with better controls, the rate of recent incursions is over controls, the rate of recent incursions is over double the annual rate for the last 100 years.double the annual rate for the last 100 years.

Horticulture is the major Horticulture is the major culpritculprit

• 30% of the worst noxious weeds and 7 of the 18 30% of the worst noxious weeds and 7 of the 18 worst environmental weeds were originally worst environmental weeds were originally introduced as garden plants.introduced as garden plants.

• species that naturalised in Australia between species that naturalised in Australia between 1971-1995 were introduced as:1971-1995 were introduced as:

- garden ornamentals 65%,- garden ornamentals 65%,

- agriculture 7%- agriculture 7%

- seed contamination 2%.- seed contamination 2%.

Weeds are yesterdays fashion Weeds are yesterdays fashion statementstatement

• Most of the weeds of horticultural origin are no Most of the weeds of horticultural origin are no longer in horticulturelonger in horticulture

• We introduce new garden plants as soon as the We introduce new garden plants as soon as the older ornamentals fall out of favourolder ornamentals fall out of favour

Tomorrows weeds are already Tomorrows weeds are already herehere

• even if Australia closed its doors on all imports even if Australia closed its doors on all imports today, our alien plant numbers would still increasetoday, our alien plant numbers would still increase

• thousands of aliens have already entered the thousands of aliens have already entered the countrycountry

• sleepers are all around us, in our gardens, on our sleepers are all around us, in our gardens, on our farms and plantations, in laboratories and aquariafarms and plantations, in laboratories and aquaria

• most garden plants are wilful, wild organisms - most garden plants are wilful, wild organisms - survive and reproduce survive and reproduce

The Darwin example - The Darwin example - Mimosa Mimosa pigrapigra

• introduced into the gardens in the 1880’sintroduced into the gardens in the 1880’s• a sleeper for nearly 100 yearsa sleeper for nearly 100 years• in the 1970’s it exploded into the wetlandsin the 1970’s it exploded into the wetlands• now covers about 80,000 hectares of World now covers about 80,000 hectares of World

Heritage listed wetlandsHeritage listed wetlands

The Darwin example - The Darwin example - Mimosa Mimosa pigrapigra

• now number 10 on the list of declared ‘Weeds of now number 10 on the list of declared ‘Weeds of National Significance’National Significance’

• our conservation effort in the Botanic Gardens our conservation effort in the Botanic Gardens pales into insignificance against the monetary and pales into insignificance against the monetary and environmental costs of one introduced alienenvironmental costs of one introduced alien

Botanic Gardens – part of the problem – Botanic Gardens – part of the problem – part of the solutionpart of the solution

• weed researchers have identified many research weed researchers have identified many research prioritiespriorities

• some are beyond the remit of Botanic Gardenssome are beyond the remit of Botanic Gardens

• there are some that gardens can be involved with there are some that gardens can be involved with

Botanic Gardens - a redistribution of Botanic Gardens - a redistribution of efforteffort

• Detecting new weeds - early alert systemsDetecting new weeds - early alert systems

• Research into weed life historyResearch into weed life history

• Identification of ‘sleeper’ weedsIdentification of ‘sleeper’ weeds

• Weed Risk Assessment modelsWeed Risk Assessment models

• Education and community engagementEducation and community engagement

Weed Risk AssessmentWeed Risk Assessment

• the identification of potentially invasive species the identification of potentially invasive species prior to importationprior to importation

• the potential seriousness of a new outbreakthe potential seriousness of a new outbreak

• potential sleeperspotential sleepers

• identification of knowledge gaps in individual weed identification of knowledge gaps in individual weed speciesspecies

Species characteristicsSpecies characteristics

History of invasive behaviour elsewhere

Relatedness to species that show invasive behaviour

Climatic match between original range and proposed introduction area

Noxious and undesirable traits

Biological attributes of the plant itself

Modified Weed Risk Assessment Modified Weed Risk Assessment SchemesSchemes

• particular ecosystems e.g. adaptation particular ecosystems e.g. adaptation of the New of the New Zealand scheme for the insular terrestrial flora of Zealand scheme for the insular terrestrial flora of the Galapagos Islands;the Galapagos Islands;

• particular life forms e.g. adaptation of the New particular life forms e.g. adaptation of the New Zealand scheme to aquatic weeds;Zealand scheme to aquatic weeds;

• particular vegetation types e.g. woody invaders in particular vegetation types e.g. woody invaders in South African fynbos flora;South African fynbos flora;

• particular bioregions e.g. adaptation of the particular bioregions e.g. adaptation of the Australian scheme to the Wet Tropics bioregion of Australian scheme to the Wet Tropics bioregion of northern Australia.northern Australia.

Weed Risk Assessment:Weed Risk Assessment:A matter of scaleA matter of scale

• discriminate between invaders and non-invaders – discriminate between invaders and non-invaders – often over 80% success rateoften over 80% success rate

• does not quantify the magnitude or type of does not quantify the magnitude or type of impacts.impacts.

• as a pre-import tool, impact is not measured in the as a pre-import tool, impact is not measured in the target countrytarget country

• national level WRA models are unlikely to be well national level WRA models are unlikely to be well adapted for use at a more local scale.adapted for use at a more local scale.

• below the national scale, the focus of WRA below the national scale, the focus of WRA becomes increasingly on assessing the impact of becomes increasingly on assessing the impact of aliens and prioritising response actions. aliens and prioritising response actions.

Weed Risk Assessment in Botanic Weed Risk Assessment in Botanic GardensGardens

• the criteria need to become more focused on the the criteria need to become more focused on the local environmentlocal environment

• Botanic Gardens should focus on assessing Botanic Gardens should focus on assessing horticultural plants as potential environmental horticultural plants as potential environmental weedsweeds

• as the geographic scale becomes more local, the as the geographic scale becomes more local, the data, the research and resourcing requirements to data, the research and resourcing requirements to undertake and implement a WRA may increase.undertake and implement a WRA may increase.

• However, if Gardens focus on the environmental However, if Gardens focus on the environmental weed issue, it appears the model can be made weed issue, it appears the model can be made relatively easy to use.relatively easy to use.

Weed Risk Assessment in Botanic Weed Risk Assessment in Botanic GardensGardens

• the Australian national WRA system requires the Australian national WRA system requires information against 90 criteriainformation against 90 criteria

• a model in a Botanic Gardens has only 30 criteriaa model in a Botanic Gardens has only 30 criteria• horticultural ground staff are enthusiastic about horticultural ground staff are enthusiastic about

being involved and with having a system that they being involved and with having a system that they can implementcan implement

• the process recognised the need to develop a data the process recognised the need to develop a data base to capture staff observational information.base to capture staff observational information.

Education and Community Education and Community EngagementEngagement

““No plant is inherently ‘bad’, but rather that No plant is inherently ‘bad’, but rather that gardeners sometimes make poor choices”gardeners sometimes make poor choices”

• alien species becomes a question of gardening alien species becomes a question of gardening ethics – ‘What plants to grow?’ ethics – ‘What plants to grow?’

• gardeners must develop a new ethos of ecological gardeners must develop a new ethos of ecological responsibility in what they plantresponsibility in what they plant

• Botanic Gardens also send a strong public Botanic Gardens also send a strong public message that what they display are good garden message that what they display are good garden plantsplants

A national approach to A national approach to garden escapeesgarden escapees

• involves local, state, and involves local, state, and federal government agenciesfederal government agencies

• involves the plant industry and involves the plant industry and horticultural mediahorticultural media

• wide dissemination of listed wide dissemination of listed ‘Garden Thugs’‘Garden Thugs’

• a black list of 958 speciesa black list of 958 species• on-going assessment of weedy on-going assessment of weedy

potential of garden plants potential of garden plants

Garden Plants Under the SpotlightGarden Plants Under the Spotlight

• education programs education programs encourage encourage replacement of garden replacement of garden plants of weedy plants of weedy concern with non-concern with non-weedy alternativesweedy alternatives

Garden Plants Under the SpotlightGarden Plants Under the Spotlight

• the strategy urges adoption the strategy urges adoption of self-regulation within the of self-regulation within the industryindustry

• industry support includes a industry support includes a voluntary ban on selling the voluntary ban on selling the worst behaving garden worst behaving garden plantsplants

• nurseries should know the nurseries should know the species that are ‘weedy’ in species that are ‘weedy’ in their area and not stock their area and not stock them. them.