00:00 From rats, cats and mosquitoes to a rogue's gallery of plants, a major scientific assessment
00:08 Monday catalogued more than 37,000 alien species worldwide, 10% of them classified as aggressively
00:15 harmful or invasive.
00:18 The failure is costing well over $400 billion a year in damages and lost income, the equivalent
00:24 to the GDP of Denmark or Thailand, and that is likely a gross underestimation, according
00:30 to the Intergovernmental Science Advisory Panel for the UN Convention on Biodiversity.
00:36 From water hyacinth choking Lake Victoria in East Africa, to rats and brown snakes wiping
00:41 out bird species in the Pacific, to mosquitoes exposing new regions to Zika, yellow fever,
00:46 dengue and other diseases, the report catalogued more than 37,000 so-called alien species that
00:52 have taken root, often literally, far from their places of origin.
00:58 That number is trending sharply upward, along with the bill for the damage, multiplying
01:02 fourfold per decade, on average since 1970.
01:06 Economic expansion, population increase and climate change will increase the frequency
01:10 and extent of biological invasions and the impacts of invasive alien species, the report
01:15 concluded.
01:16 Only 17% of countries have laws or regulations to manage this onslaught, it said, whether
01:21 by accident or on purpose, when non-native species wind up on the other side of the world,
01:26 humans are to blame.
01:27 The spread of species is hard evidence that the rapid expansion of human activity has
01:31 so radically altered natural systems as to tip the earth into a new geological epoch,
01:36 the Anthropocene scientists say.
01:39 The hyacinth that at one point covered 90% of Lake Victoria, crippling transport, smothering
01:43 aquatic life, blocking hydroelectric dam intake and breeding mosquitoes, is thought to have
01:48 been introduced by Belgian colonial officials in Wanda as an ornamental garden flower before
01:53 making its way down the Caguera River in the 1980s.
01:56 The Florida Everglades is steaming with the destructive offspring of earth-spread pets
02:00 and houseplants, from 5-metre Burmese pythons and walking catfish to old world-climbing
02:05 fern and Brazilian pepper.
02:07 In the 19th century, English settlers brought rabbits to New Zealand to hunt for the food.
02:11 When they multiplied, officials imported ferocious little carnivores called stoats to reduce
02:15 their numbers, but the stoats were often easier prey, dozens of endemic bird species that
02:20 were soon decimated from baby kiwis to rivals.
02:23 New Zealand and Australia, where a similar batch-to-bird saga involving rabbits unfolded,
02:27 are case studies of how not to control one imported pest with another, Elaine Murphy,
02:32 a scientist at New Zealand's Department of Conservation, explained.
02:36 Murder hornets capable of wiping out entire bee colonies in a single attack are thought
02:40 to have arrived in the US from Asia as stowaways in freight.
02:44 Largely due to huge volumes of trade, Europe and North America have the world's largest
02:48 concentrations of invasive species, defined as those that are non-native and cause harm
02:52 and have relocated due to human activity, the IPBES report showed.
02:57 Invasive species are a significant cause in 60% of all documented plant or animal extinctions,
03:02 one in five main drivers along with habitat loss, global warming and pollution, according
03:07 to the findings.
03:09 These drivers interact.
03:10 Climate change has pushed alien species into newly warmed waters or lands where native
03:14 species are often vulnerable to intruders they have never encountered.
03:18 The deadly fire that reduced the Hawaiian town of Lahaina on Maui to ashes last month
03:22 was fuelled in part by bone-dry grasses imported decades ago to feed livestock that has spread
03:27 across abandoned sugar plantations.
03:29 A global treaty to protect biodiversity hammered out in Montreal last December sets the target
03:34 of reducing the rate at which invasive alien species spread by half by 2013.
03:38 There are basically three lines of defence, according to the report, prevention, eradication
03:42 and then failing that, containment.
03:44 Attempts at eradication have generally failed in large bodies of water and open waterways
03:48 as well as on large tracts of contiguous land.
03:51 The places with the highest rate of success in removing unwanted guests, especially rats
03:55 and other vertebrates, are also the ones that have proved most vulnerable.
03:59 Small islands.
03:59 [Music plays]
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