The Changing Environment Trivia Quiz

Answer: On ships

There have been numerous accidental introductions over the centuries. Small creatures and seeds in ship cargoes is the obvious way. When British ships sailed to the American colonies, soil was used as the ships ballast, to be dumped on arrival to make way for the return cargo. This was how the earthworm arrived in America.

The change to steel-hulled ships saw seawater becoming the ballast of choice. It is estimated that 7 billion tonnes of seawater ballast are carried around the world each year. At any one time, an estimated 7,000 different species are travelling this way.

Answer: Mouse

Being mainly herbivores, you would think that house mice would not be an issue. Species however often adapt to new environments. The mice developed a taste for meat and grew in size, doubling their average weight in the process.

With Gough Island being tree-less, the island's ten million bird inhabitants nest in borrows. Not having evolved to deal with such predators, it does not end well for the chicks. Mice have been observed successfully tackling birds up to 300 times their size.

Mice eat a fifth of their body weight daily. For an estimated two million mice, this equates to about two tonnes of bird flesh daily, which is no doubt why the bird population is collapsing.

Answer: The works of William Shakespeare

Eugene Schieffelin, a Bronx pharmacist and one-time chairman of the American Acclimatization Society, was a fan of Shakespeare's works. Many of his Shakespearean imports failed, but the European starling was an exception, just a bit too successful. It is now North America's most numerous bird at around 200 million and is considered an invasive species. It gets briefly mentioned by Hotspur (Henry Percy) in Act 1, Scene 3 of 'Henry IV Part 1'.

There was a follow-up in the form of a garden in Central Park, New York containing all the plants mentioned by Shakespeare.

Answer: Rain

Accidentally finding its way into Lake Victoria in the 1980s, it spread prolifically in the 1990s blocking supply intakes for hydro-electric generators, preventing local fishermen from launching their boats, removing oxygen from the water and harbouring snakes, crocodiles and disease-carrying insects.

Herbicides, weevils (with a taste for the plant) and mechanically harvesting were all tried with limited effect. It was an El Niņo event in 1998, causing unseasonal rains and much flooding, that had the biggest impact. The effect was to flush the lake of nutrients. Without nutrients the water hyacinth went into decline.

It is easy to blame the plant for the problems, but the cause is arguably man-made. Cities, industries and agriculture had filled the lake with pollution, sewage and other nutrients, creating the conditions for the plant to flourish. Following the El Niņo-caused rains of 1998, nutrient levels are on the rise again and so is the water hyacinth.

Answer: Water hyacinth

All of these can be used to make bio-gas and feed livestock, however it is the water hyacinth that can deal with the pollution. The plants thrive in waterways polluted by industrial effluents and can happily remove heavy metals. It is probably best not to use the plant grown in such conditions to feed livestock.

The water hyacinth is also relatively high in hydrocarbons, making it a good candidate for bio-gas generation.

Answer: Zebra mussel

Zebra mussels are filter feeders and dramatically improved the visibility in the lake as well as reducing pollution levels. This has resulted in changes to the lake's ecology such as plants migrating to greater depths with the improved sunlight penetration and some fish following. The increased visibility also makes diving a more pleasant experience.

The mussel has also contributed to the recovery of the lake sturgeon, a species that has been around for 136 million years or so. Both the lake sturgeon and the smallmouth bass are known to eat the zebra mussel. It also helps that commercial fishing of the lake sturgeon is banned in the US. Considered a pest in the early nineteenth century and a money-making resource in the latter half of that century, the lake sturgeon was driven to near-extinction by the impacts of overfishing, habitat loss, dam construction and pollution.

The Cuyahoga, at times one of the most polluted rivers in the US, famously caught fire in 1969. In fact, this was only one of thirteen such occasions. There have been various initiatives to reduce pollution going into the lake and these will also have contributed to a reduced eutrophic environment.

Answer: The rabbit-eating cats ate birds instead

Conservationists have had most success winding back time with remote islands, although trying to remove alien species often has unintended consequences. Macquarie Island, with its large bird colonies, lying halfway between New Zealand and Antarctica was discovered by seal hunters in 1810. Rats and mice jumped ship, cats were brought in to hunt the rats and rabbits were released to provide food during stop-overs. The rabbits flourished reaching an estimated 150,000 by the mid-20th century.

The virus got rid of 90% of the rabbits. The cats, which had been eating rabbits and rats, started eating numerous birds. The cats were then shot so rat and rabbit numbers mushroomed. The rats ate the birds, the rabbits caused a landslip which wiped out an important penguin and albatross colony. Poison drops then targeted the rabbits and rodents but also killed a few thousand birds. Dogs were used to get the last thirteen rabbits. It is hoped all the rats and mice have also gone.

Ecological cleansing has been attempted on a much larger scale. South Africa has deployed 25,000 people since 1995 under the Working for Water scheme. The main reason for removing non-native trees is given as water conservation, making a scarce resource available for more productive use. It has probably been most effective as an employment scheme.

Answer: Rinderpest virus

The virus arrived in Eritrea in the Horn of Africa with a small force of Italian soldiers in 1887. They brought their own food in the form of infected cattle. The virus was new to Africa and reached South Africa within a decade wiping out the great cattle herds as well as many cloven-hoofed wild animals. Although unaffected by the virus itself, millions of Africans died of starvation and other diseases which took hold in their weakened state. Two-thirds of the pastoral Masai are thought to have died in 1891. It was during this period that European powers colonised the depopulated east Africa.

Before the arrival of the rinderpest virus, the native tsetse fly was confined to Africa's lowland tropical bush where it got the vegetation needed for its larvae. With the death of the cattle, the grazing pastures turned into bush as there was no cattle left to graze it down. This allowed the tsetse to expand its range enormously when the wild animal population rebounded. The tsetse fly brought sleeping sickness to the surviving people and millions more people have died since as a result.

The tsetse fly's expansion caused some of the most fertile areas of Africa to become no-go areas. This was the depopulated and primaeval wilderness Roosevelt encountered. He was to eventually send more than 11,000 animal carcasses to the Smithsonian Museum in Washington from his safari.

Answer: Ascension Island

Discovered by Portuguese sailors on Ascension Day in 1503, by the mid-19th century this mid-Atlantic island had been grazed barren by introduced animals such as goats, rabbits and sheep. Charles Darwin, dropping by in HMS Beagle in 1836, described the island as 'not smiling with beauty, but staring with naked hideousness'.

A friend and plant collector James Hooker visited in 1843 and came up with the idea of greening or terra-forming the island to help improve the water supply for the island's inhabitants. It worked. The 300 new plant species as well as introduced insects and animals now make up 90% of the species present. The cloud forest on Green Mountain (as it is now called) has been designated a national park.

Answer: Rabbit

The European rabbit (Oryctolagus cuniculus) originally comes from the Iberian peninsula and southern France. According to one reference, the rabbit was originally introduced by the Romans around 2,000 years ago as a food source. Another places the date 1,000 years later.

The Euroasian beaver (Castor fiber) was hunted to extinction in Britain about 300 years ago but has recently been reintroduced from Norway. It has been given native status in Scotland.

There are others that are often considered native but actually have been introduced. These include the brown rat, black rat, edible doormouse, European hare and fallow deer.

What constitutes native or indigenous in a UK context varies however it usually means that it was present at least 8,000 years ago when the English Channel was formed. None of the current crop of native animals were likely to have been present 12,000 years ago when the UK was completely covered by ice.

It has been estimated that 90% of non-native species cause no issues in their new environment. In fact they can have a positive effect with natives sometimes becoming dependent on them. Both natives and non-native species adapt. Of the 10% of non-natives that have an impact, most are soon forgotten about. It is the 1% that tends to attract most of the negative attention.