Frequently Asked Questions
The scope of the database is terrestrial arthropod pests and plant pathogens. Weeds, vertebrate pests, aquatic pests, and animal diseases are not currently included.
Rates of invasion of unwanted species are increasing around the world for various reasons, such as:
- increased rates of international travel and trade;
- changing patterns (i.e. origins) of travel and trade;
- increasing diversity of unwanted species in trading partners, due to invasions there;
- increasing urbanisation of pest species;
- climate change; and
- natural selection for "invasiveness".
Therefore biosecurity managers are facing increasing volume and diversity of invaders, and it is inevitable that some of these successfully establish. Many authorities implement surveillance activities to detect invasions early enough to attempt eradication. In other cases, new technologies or economic imperitives may enable eradication of already well-established pests. The science and practice of eradication is developing rapidly.
This database compiles information on historical and current eradication programmes to give biosecurity practitioners rapid access to international experience and expertise. Ultimately, the database aims to improve the success rate and efficiency of future eradication programmes by improving transfer of knowledge between eradication practitioners, by
- collating and summarising information on past eradication attempts against particular species;
- identifying characteristics of invasive species which make them easy or difficult to eradicate;
- helping managers to quantify the feasibility and likely costs of potential eradication programmes;
- identifying the eradication tools that might be used against particular pests;
- tracking the efficacy of new eradication tools;
- linking to published documentation and literature on eradications;
- making available unpublished information and experience which would otherwise be lost; and
- demonstrating the track-record of successes and failures of particular countries or against particular targets.
These aims mirror those of the Global Island Invasive Vertebrate Eradication Database which compiles information on eradications of vertebrate pests from islands.
The word "eradicate" originates from the Latin "to uproot" (eradicatus).
In ecology, eradication is the intentional local extinction, or extirpation, of a particular taxon. This involves the killing or complete removal of every individual of the target taxon from a defined area, i.e. achieving population size zero.
The target taxon is most often a species, but may sometimes be a subspecies or more than one closely related species. Eradication programmes almost always target pestiferous invasive species in part of their invaded range.
The target area for an eradication may vary greatly in size. Often eradications are carried out in geographically isolated areas, such as islands, to minimise the risk of reintroduction. Sometimes, however, eradications may target a particular part of a species' range because of the environmental, economic, or political benefits of removal, even if the species is likely to reinvade.
One of the biggest challenges of any eradication programme is demonstrating success. The International Plant Protection Convention specifies standards for plant pest eradications in its International Standards for Phytosanitary Measures No 9, but these are largely descriptive. Current international practice specifies that, provided that reasonable surveillance activity has been carried out, eradication of most plant pests can be declared once there have been no detections for at least three times the normal generation time of the target taxon.
It is a subjective decision as to whether a particular activity constitutes and "eradication attempt". For inclusion in this database, management programmes must satisfy three main criteria:
The stated management aim should have been eradication. Therefore, pest management programmes or trials of pest reduction technologies do not qualify for inclusion, unless eradication was fortuitously achieved. The latter are included because they can inform the effort and expenditure required to achieve eradication. Pest management programmes which do not achieve eradication are not included because without the intent of eradication they omit the greatest technical challenges of any eradication campaign: achieving and demonstrating the absence of the very last target individual.
Similarly, spatial containment programmes are not included. Often new incursions are initially managed for containment while enough information is gathered to determine the likely costs and benefits of attempting eradication. In such cases, the word "eradication" may be used but without this being the current aim of management. Such cases are not included unless there is evidence that the management aim has eventually changed from containment to eradication. As with pest management, there may be cases where eradication was achieved fortuitously during a containment programme, and these may be included.
- Temporal distinction
For inclusion in the database, management programmes should have achieved absence from the eradication zone for at least one year, or three times the normal generation time of the target taxon, whichever is larger. For species with very short generation times, such as many mosquitoes and fruit flies, temporal distinction is not clear-cut, especially when monitoring tools are imperfect or there are active pathways of reintroduction. In some cases, pest populations may reappear in the same area some time after eradication was thought to have been achieved. and this may indicate either that the previous eradication attempt was unsuccessful or simply reintroduction. If the issue is in doubt, then the first programme is marked as "likely eradication" rather than "confirmed eradication".
Note that many reported mosquito "eradication" programmes are excluded from the database because they are simply short-term (annual) actions aiming to reduce local densities to below nuisance levels, with no expectation for long-term population impacts.
- Spatial separation
It is sometimes difficult to decide whether eradication actions against the same taxon in adjoining political areas (e.g. countries or states) should be considered as separate programmes or not. When separate political administrations have been largely responsible for management actions in adjoining regions, then these are included separately. However, when the responses are conducted under the auspices of a common political or advisory body, then they are grouped. For example, the cotton boll weevil response in the United States spanned many political regions (states) but was largely driven by the industry in a coordinated fashion, so this has been included as a single eradication programme.
In the case of local European gypsy moth responses in the United States (beyond the "slow the spread" zone), local responses have been separated spatially by county and temporally by at least two years.
In some cases, an eradication programme may be carried out despite there being no local population found. For example, the find of a single gypsy moth male in a monitoring trap in Hamilton, New Zealand, was sufficient to prompt a programme of quarantines and aerial biopesticide applications. Such cases are included in the database, but with the infested area recorded as zero so that they can be easily excluded from analysis if required.
Similarly there are cases where there is no evidence that founder populations have actually established and spread. An example would be Asian longhorn beetles found infesting a tree that was imported, sold and planted in someone's garden. Such cases are included in the database because the IPPC, under ISPM9, classifies the resulting clean-up as an eradication.
Ideally, the primary source of eradication information is the peer-reviewed scientific literature, and this has been the case for some of the data in the database.
Unfortunately, the outcomes of historical eradication attempts have rarely been reported in the peer-reviewed literature, especially for failed attempts. Therefore, an important secondary source of information has been searches of the "grey literature", including unpublished reports, conference proceedings, media releases and news reports.
In some cases, important data have been obtained through personal communications with the managers involved in particular eradication programmes.
At the same time that the current database was established, the European Union PRATIQUE programme (Baker et al. 2009) independently collected and analysed data on plant pest eradication and containment programmes. Once the two efforts became aware of each other we worked together, and the appropriate PRATIQUE data have been included here.
Baker RHA, Battisti A, Bremmer J, Kenis M, Mumford J, Petter F, Schrader G, Bacher S, De Barro P, Hulme PE, Karadjova O, Lansink AO, Pruvost O, Py, ek P, Roques A, Baranchikov Y, Sun JH 2009. PRATIQUE: a research project to enhance pest risk analysis techniques in the European Union. EPPO/OEPP Bulletin 39: 87-93.
To compare the costs of different eradication programmes worldwide these have been converted to a common currency: the 2015 United States dollar (USD).
First, historical annual average exchange rates have been used to convert local currencies to the USD, as described by Officer (2009).
Then the USD amounts have been standardised to the year 2005. There are many different "inflation rates" that might be used to do this conversion, some of which will inflate early years more than others. These are described by Williamson (2010). Here, we have used the "GDP deflator", that represents the average price of all the goods and services produced in the economy. Since eradication programmes involve a combination of fixed and variable costs for manpower and materials, this arguably provides a better index of cost than other methods which rely on either the price of household consumables or the cost of unskilled labour.
The data used to make the conversions were sourced from the MeasuringWorth websites cited below.
Officer LH 2009. Exchange rates between the United States dollar and forty-one currencies. MeasuringWorth, http://www.measuringworth.com/exchangeglobal (updated December 2010).
Williamson SH 2010. Seven ways to compute the relative value of a U.S. dollar amount, 1774 to present. MeasuringWorth, http://www.measuringworth.com/uscompare (updated April 2010).
Every endeavour has been made to include only the most reliable data in the database. However, given the patchiness of the available information, and the fact that much of it is (by necessity) sourced from the media and the grey literature, it is possible that you may notice some inaccuracies or errors.
If you do see an error, we would appreciate it if you could let us know about it and, if possible, provide a correction.
Your contributions are welcomed! Please see the user manual for guidelines.
A great deal of effort has been used to compile these data in one place and to make them easily accessible. Therefore, if you make use of any data from here, we would appreciate a message from you, and an appropriate citation in your publication or presentation. This will help us to keep up to date our list of publications using the database and to justify the ongoing expense of maintaining and updating the data.
The database should be cited as:
Kean JM, Suckling DM, Sullivan NJ, Tobin PC, Stringer LD, Smith GR, Kimber B, Lee DC, Flores Vargas R, Fletcher J, Macbeth F, McCullough DG, Herms DA et al. 2021. Global eradication and response database. http://b3.net.nz/gerda (accessed 21 June 2021).
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