Prevention measurements are the most important strategy to avoid the spreading of weeds. Therefore, we have to know those taxa and we have to promote a deeper awareness about this plants among all of us. If the main efforts are focused on these two aspects, the chance of success will be greater.

The measurements will be different depending on each case, e.g.: dispersal by seeds, fruits or plant fragments.

For example, in the Mediterranean area, many ornamental plants come from South Africa, and can become invasive plants. So, we should be careful and implement policies and measures to control import of such species or varieties. Moreover, waste from garden centers and private gardens should be controlled.

Government authorities, the scientific community and the general public should be involved in this process.

Please, check the below links. You can find some interesting ideas. This may be of your interest.

Boy, G. 2013. Invasive alien plants and their management in Africa.

http://www.cabi.org/Uploads/CABI/publishing/promotional-materials/african-invasives-book.pdf

GISP, 2000. Global strategy on invasive alien species.

http://www.cites.org/common/com/ac/16/E16-Inf-12.pdf

In North America, the problem with weeds in wildlands has been the intentionally sown exotics, by the millions of pounds per year, mostly by government agencies and highway departments. A 2,000 mile survey in 1997 at http://www.ecoseeds.com/megatransect.html of the Western states, showed that weeds were a minor problem compared to the intentionally sown weedy exotics. You can also read http://www.ecoseeds.com/juicy.gossip.six.html.

Thanks Carlos and Craig for the response and references very helpful. Certainly prevention is the best method since control and eradication are very expensive and in most cases are not even successful. From my review papers it appears species from most taxa can benefits from human introduction, yet, less is being done to prevent them. Now there is even increase in online sales of seeds. I am not sure if there are also current advances in technologies that can help reduced transportation of seeds, particularly on vehicles and human clothing.

This is important. There are dozens of practical guidelines available. Search the words biosecurity, conservation, and islands and you can get some useful documents. Check the term "pathway" analysis and invasive species/plants. Prevention is the most effective means of managing invasive species, no introduction=no problem! Human behavior is the problem and the solution. It is generally agreed that efforts to increase awareness in stakeholder groups is important. Most environmental weeds were intentionally introduced for use as ornamental or "useful" plants, this is true most everywhere (usually >75%) e.g., see the overview we wrote for New Zealand weeds back in the 1990s.

One issue is that the costs imposed on society and the environment are not borne by the entity introducing the weed. Policy should attempt to internalize the externalities - this is economic speak for making the polluter pay, whereas normally the polluter (the person introducing the weed) may get some small benefit (e.g. sale at plant nursery or because it looks nice in their garden) the costs can balloon out of control quickly if the plant spreads, realizes its impacts, and effort is invested in its control. Meanwhile the introducing entity is not responsible for paying any of that.

At a more local and practical level the typical strategy is to use washed or new clothes, or site specific clothes for work in areas you are trying to protect from new introductions. Often certain weedy garden plants cannot be eaten while doing field work in isolated sites e.g. tomato. Clothes and boots are cleaned or brushed between trips. Campsites are monitored and plants recorded, new weeds are removed as they are detected.

For countries or regions border control can be used to prevent new introductions, also weed risk assessments may be required for new intentional introductions. Take a trip to New Zealand or Australia and you will see how much importance is placed on prevention.

For pests the US government (USDA) produces pest risk assessments....this includes pathway risk assessments associated with imported food crops.

Often farming communities implement equipment cleaning protocols to prevent spread of weeds from one region to another.

The Hawaii Invasive Species Council has a full strategy document that includes prevention efforts for invasives there. See http://dlnr.hawaii.gov/hisc/files/2013/02/20080809hiscstrategicplan.pdf.....

In the Galapagos they use a protocol for work done on uninhabited islands and within the National Park: http://www.galapagospark.org/nophprg.php?page=ciencia_investigacion_protocolos, http://www.galapagospark.org/documentos/protocolos_campo_galapagos.pdf

I have not done an extensive compiling of examples but work on offshore islands or in isolated sites in NZ requires that visitors (not the least of which includes conservation workers and scientists) do not introduce pest plants or animals. For an example check this link:

http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1003&context=nwrcinvasive

A useful video for workers visiting isolated Islands in the North west Hawaiian islands is given here: https://www.youtube.com/watch?v=1Yg2mSjuQmI Here weeds could include introduced invasive marine plants and algae.

Hope this helps.

Chris

I see you have written a fair amount on this subject, good work.

Thanks Chris, very detailed response, Do have the English version of the protocol used in the Galapagos..

I recall seeing an English version but cannot find it. You might be interested in this: http://www.darwinfoundation.org/datazone/media/pdf/63/GR_63_2005_Jaramillo_et_al_Viability_of_seeds.pdf

VIABILITY OF SEEDS IN FOOD PRODUCTS PROPOSED FOR

FIELD TRIPS IN GALAPAGOS