Tag: exotic species

Unwelcome guests: International tourism and travel can be a pathway for introducing invasive species

International tourism can facilitate the dispersal of exotic species. A new analysis of data from tourism accommodations and exotic organism detections in New Zealand, published in NeoBiota, shows that levels of detection significantly correlated to international and domestic tourist movement, even with population levels taken into account. There was no detectable difference between the risk from international and domestic tourists, indicating that tourism as an activity correlates with the introduction and spread of exotic species.

Tourists, albeit unwittingly, may help such unwanted organisms spread further and conquer new lands – they can carry them over in their luggage or on their clothes and shoes. In 2011, a study from New Zealand found that, for every gram of soil on the footwear of aircraft passengers arriving from abroad, there were 2.5 plant seeds, 41 roundworms, 0.004 insects and mites, and many microorganisms, such as fungi that could cause plant diseases. Moreover, these organisms were alive, and some of them were known to be biosecurity threats. Importantly, tourism can introduce risk in two directions, namely from the arrival of international travellers and also the return of residents from international travel.

An important question, then, is to what degree they play a role in the spread of exotic organisms. A study, carried out by Dr Andrew Robinson of the Centre of Excellence for Biosecurity Risk Analysis at the University of Melbourne and Mark McNeill of AgResearch New Zealand, looks to answer that question.

To do so, the researchers compared data on the interceptions of exotic organisms in New Zealand against accommodation data for international and domestic tourists, factoring for the country’s population distribution. The study, recently published in the open-access journal NeoBiota, covered the period between 2011 and 2017, and the exotic organisms that were detected included insects, spiders, mites, snails, plants, and roundworms. 

Robinson and McNeill found a significant relationship between levels of incursion detection and tourism accommodation records: the number of nights spent in hotels significantly correlated to the detection of exotic pests for that period. Importantly, the study found no significant difference between the effect of international and domestic tourism, proving that even travel within the country can facilitate the spread of exotic species. A significant positive correlation was also found between the detection of exotic organisms and population numbers across different regions. 

“The core take-home message is that within-country tourism movements are significantly correlated to the detection of exotic pests,” the researchers explained. That is, tourists and returning residents bring bugs in, and both are implicated at spreading them once they are in the country. They suggest that biosecurity authorities should continue allocating resources to the management of invasive species and pests that get carried around by tourists and their activities. 

However, they also point to the biosecurity risk posed by other possible pathways for of exotic organisms, such as sea freight. A comparison between the different ways of introduction and dispersal would provide a better understanding of relative risk, they conclude.

Research article:

Robinson AP, McNeill MR (2022) Biosecurity and post-arrival pathways in New Zealand: relating alien organism detections to tourism indicators. NeoBiota 71: 51-69. https://doi.org/10.3897/neobiota.71.64618

Tiger geckos in Vietnam could be the next species sold into extinction, shows a new survey

The endemic reptiles are already proposed to be listed by the Convention on International Trade in Endangered Species of Wild Fauna and Flora

While proper information about the conservation status of tiger gecko species is largely missing, these Asian lizards are already particularly vulnerable to extinction, as most of them have extremely restricted distribution. Furthermore, they have been facing severe declines over the last two decades, mostly due to overcollection for the international exotic pet market. Such is the case of the Cat Ba Tiger Gecko, whose tiny populations can only be found on Cat Ba Island and a few islands in the Ha Long Bay (Vietnam).

In their study, a Vietnamese-German research team, led by PhD candidate Hai Ngoc Ngo of the Vietnam National Museum of Nature in Hanoi, provide an overview of the evidence for domestic and international trade in tiger gecko species and update the information about the abundance and threats impacting the subpopulations of the Vietnamese Cat Ba Tiger Gecko in Ha Long Bay.

By presenting both direct and online observations, interviews and existing knowledge, the scientists point out that strict conservation measures and regulations are urgently needed for the protection and monitoring of all tiger geckos. The research article is published in the open-access journal Nature Conservation.

Cat Ba tiger gecko (Goniurosaurus catbaensis) in its natural habitat. Photo by Hai Ngoc Ngo.

Tiger geckos are a genus (Goniurosaurus) of 19 species native to Vietnam, China and Japan. Many of them can only be found within a single locality, mountain range or archipelago. They live in small, disjunct populations, where the population from Ha Long Bay is estimated at about 120 individuals. Due to demands in the international pet trade in the last two decades, as well as habitat destruction, some species are already considered extinct at the localities where they had originally been discovered.

However, it was not until very recently that some species of these geckos received attention from the regulatory institutions in their home countries, leading to the prohibition of their collection without a permit. Only eight tiger geckos have so far had their species conservation status assessed for the IUCN Red List. Not surprisingly, all of them were classified as either Vulnerable, Endangered or Critically Endangered. Nevertheless, none is currently listed by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which could be the only efficient and reliable method to monitor, regulate and police the trade of the species on a global scale.

“Tiger geckos are neither sufficiently protected by law nor part of conservation programmes, due to the lack of substantial knowledge on the species conservation status and probably due to the general lack of public as well as political interest in biodiversity conservation,” they explain. “To date, exact impacts of trade on the species cannot be identified, as data of legal trade are only recorded for species listed in the CITES Appendices”.

During their survey, the researchers tracked local traders in possession of wild-caught tiger geckos representing all five Vietnamese species en route to foreign exotic pet markets, mainly in the United States, the European Union and Japan. The species were also frequently found to be sold in local pet shops in Vietnam, as well as being offered via various online platforms and social media networks like Facebook.

Having spoken to local dealers in Vietnam, the team found the animals were traded via long and complex chains, beginning from local villagers living within the species’ distribution range, who catch the geckos and sell them to dealers for as little as US$4 – 5 per individual. Then, a lizard either ends up at a local shop with a US$7 – 25 price tag or is either transported by boat or by train to Thailand or Indonesia, from where it is flown to the major overseas markets and sold for anywhere between US$100 and 2,000, depending on its rarity. However, many of these delicate wild animals do not arrive alive at their final destination, as their travels include lengthy trips in overfilled boxes under poor conditions with no food and water.

Indeed, although the researchers reported a large quantity of tiger geckos labelled as captive-bred in Europe, it turns out that their availability is far from enough to meet the current demands.

In conclusion, the team provides a list of several recommendations intended to improve the conservation of the Asian geckos: (1) inclusion of all tiger geckos in the Appendices of CITES; (2) assessment of each species for the IUCN Red List; (3) concealment of any currently unknown localities; and (4) improvement/establishment of coordinated ex-situ breeding programmes for all species.

Signboard handed over to the Ha Long Bay Management Department to point to the threats and conservation need of the Cat Ba tiger gecko in English and Vietnamese languages.

The inclusion of all tiger gecko species from China and Vietnam in CITES Appendix II was recently proposed jointly by the European Union, China and Vietnam and is to be decided upon at the Conference of the parties (CoP18) in May-June 2019, held in Sri Lanka.

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Original source:

Ngo HN, Nguyen TQ, Phan TQ, van Schingen M, Ziegler T (2019) A case study on trade in threatened Tiger Geckos (Goniurosaurus) in Vietnam including updated information on the abundance of the Endangered G. catbaensis. Nature Conservation 33: 1-19. https://doi.org/10.3897/natureconservation.32.33590