The legal and illegal trade in wildlife could lead to the spread of disease and invasive species, writes Dr John Measey of the Centre for Invasion Biology at Stellenbosch University in an article published on The Conversation website on Wednesday (8 March 2017).

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How do we control our desire to own a piece of the nature's beauty?

What does World Wildlife Day mean to you? Does it conjure up images of elephants rubbing up against trees in Addo National Park, or perhaps tigers stalking deer through the jungles of Bandipur-Nagarahole in southern India? In fact, World Wildlife Day (each year on 3rd March) commemorates the day on which the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) was signed. And as their name suggests, CITES is concerned with the darker side of our love affair with wildlife: the desire to have a little piece of it for ourselves.

Trade in wildlife is defined as the sale (or exchange) of wild animal and plant resources by people, and the legal side has been valued as being worth USD 160 billion in the 1990s, but by 2009 TRAFFIC estimated that the value of global imports in wildlife trade had risen above USD 323 billion. Trade in wildlife is on the increase in many economies, and that's the reason why World Wildlife Day should be of concern to you.

The Illegal trade in wildlife

The size and scale of the illegal trade is practically impossible to quantify. It has been estimated that the illegal trade in wildlife is worth hundreds of billions of dollars, but the impact on biodiversity is probably worth much more to us. The species traded form part of the network of biodiversity that used to protect us from freak weather events and the uncertain influences of changes in climate. Think of the ongoing destruction to Malagasy forests required to cut and extract rosewood trees to feed an insatiable appetite for this wood in China and Malaysia.

Trade in animals is similarly out of control. This has a negative effect not only on the species that are removed from the wild, but may subsequently lead to the spread of diseases, and some may even form invasive populations that threaten biodiversity in other areas. For example, the trade in amphibians, both for frogs' legs (yes, there is still a global demand!) and as pets, has led directly to invasive populations of many species which now threaten amphibian diversity. In addition, these animals may be responsible for the spread a fungal disease around the world, which has already driven many frog species to extinction.

What motivates us to own pieces of wild plants and animals?

Trade in wildlife is driven on three fronts: dwindling resources in many areas where people live, especially urban areas, send them or their agents back to rural settings to gather timber or bush meat. Second are the strong beliefs that pieces of animals and plants can cure ailments or enhance and restore ageing, failing organs; think of the plight of vultures or rhinos. Lastly, is our growing appreciation of the beauty of the biodiversity that the world offers. Images you'll see on the pages of this newspaper, your TV and magazines all promote the magnificence of plants and animals. Something we've failed to be able to synthesise or recreate. But how can we break the vicious circle that links our appreciation of wildlife with our desire to have a piece in our own homes?

Do you have a pet? I have a couple of dogs which come from a long line of domesticated mutts which scientists believe date back to 32 000 years ago. They are certainly a far cry from the wolves from which they were domesticated. I imagine that many of you have dogs, but a growing number of you may have an unusual pet. By this I mean an animal which has not been domesticated. A species which may have been bred locally or overseas, or may even have been collected from the wild. The demand for unusual pets in South Africa has grown at an alarming rate, and is one which mirrors what's happening in other parts of the world. Governments and NGOs are rightly concerned that this growing trend to move ever increasing numbers of different species of live animals and plants around the world. These all have to potential to become future invasive species which could carry high economic and environmental costs.

How do we decide when trade is likely to cause a problem?

This is no easy question to answer, but a group of international scientists have applied their minds to this problem to produce a scheme that can help governmental agencies decide whether a species should be traded. The information will also be made available to the public, so that you and I can be informed in the decision we make next time our offspring voice their desire to own an unusual or exotic pet.

The scheme is called EICAT (Environmental Impact Classification for Alien Taxa) and it attempts to categorise the impact caused by species which could be traded or moved accidentally with trade. It looks rather similar to the IUCN red list, and that's because it has now been adopted by the IUCN as non-partisan way to advise governments on which species are likely to cause most problems. The team of international scientists who helped dream up the scheme include researchers from Stellenbosch University's Centre for Invasion Biology (C·I·B).  These scientists are now busy trying to assess the thousands of species that have already formed invasive populations around our planet.

My own input has been to lead a team evaluating the impacts of the world's invasive amphibians. We discovered some startling impacts that outwardly humble and harmless looking frogs may have. For example, in Florida the foam nests of invasive Cuban Tree Frogs can cause shorts in transformers resulting in power-cuts. In Hawaii, property prices have slumped where invasive populations of Coqui Frogs now keep residents awake all night with their piercing calls. Perhaps most upsetting is the invasion of toxic Asian Toads in Indonesia where people regularly eat native frogs, but the poison glands of this invasive species has led to the death of at least one child. In another study, we have now found that these same toads are occasionally brought into South Africa with furniture shipments.

Can regulations on trade change the spread of disease and invasive species?

It turns out that while the alarm was being raised about the disease in frogs, trade in salamanders (newts and their relatives) was spreading another disease which threatened wild populations in North America and Europe. Then something remarkable happened: in 2015, only 2 years after the discovery of the fungus that infects salamanders and newts (Batrachochytrium salamandrivorans), the US banned all trade and movement of salamanders.

So can a ban in trade help prevent the dire consequences?

The answer is probably that the ban alone won't solve our problems. We need a public that is well informed about the consequences of participating in both legal and illegal trade as well as the consequences of apparently well-meaning actions (like taking an unwanted pet to the nearest park), and the negative consequences (spreading of disease, invasion of non-native species).

At the C·I·B, we recognise the need to provide impartial advice to governmental agencies and the public alike on the risk of trading animals and plants. We do this in our capacity as an honest broker, using scientific literature to base assessments of the impacts of each species. We believe that this work will have a positive impact on trade, not by reducing numbers or stopping people having pets, but by informing the public of the impact that species may have on our natural ecosystems. Our fascination and admiration of the natural environment may draw us closer to it, but we need to remain responsible about any desire to own a piece.

*Dr John Measey is a Senior Researcher for the Centre for Invasion Biology at Stellenbosch University.