Lecture 1: Intro To Conservation

Question 1

Anthropocene

Answer 1

Debating if entering a new era the ‘Anthropocene’ where humans are having a substantial impact on the planet.
Humans have key strengths but these leading to problems on earths systems:

• Carbon cycle (with extracting fossil fuels and causing global warming)
• Nitrogen & phosphorus cycle (putting artificial fertilisers on land)
• Ecosystem function (altered earths ecosystems)

Question 2

Problem of Anthropocene

Answer 2

Anthropocene due to:

• Large human population size.
• Human population was low until a couple hundred years ago and it increased rapidly from less than a billion to about 7.6 billion today.
• Growth is now slowing, we’ve reached the ‘demographic transition point’.
• The carrying capacity is estimated between 7.7 to 12 billion.
• The energy use by individuals is higher in some countries than in others because of differences in standard of living, greater amounts of travel, and the need to heat buildings in countries at high latitude.
• In general the higher the ecological footprint (more resources used) the higher the standard of living is.
• e.g. Americans make up 5% of world population but consume 24% of worlds energy.

Question 3

Main anthropogenic threats: Habitat destruction and degradation

Answer 3

• Over 50% of all inhabitable land surface has been converted to human use.
• Much remaining habitat has been degraded e.g. through pollution etc.
• Tropics = more recent destruction
• In developed countries = older destruction

Question 4

Main anthropogenic threats: Climate change/breakdown

Answer 4

• Emitting CO2 and other carbon based gases e.g. methane.
• Reducing the amount of carbon that’s sequestered from the environment e.g. forests and sea grass meadows that absorb CO2.

Question 5

Main anthropogenic threats: Overexploitation

Answer 5

• Common in marine/fishery environments.
• Overexploitation accelerated due to the industrialisation of fishing.
• E.g. Between 100,000 and 300,000 tons of cod were caught from a cod population in Newfoundland until 1960, then this rapidly increased to 800,000 tons. Then the population crashed by 99% and has not yet been recovered.

Question 6

Main anthropogenic threats: Invasive species

Answer 6

• E.g. the brown tree snake was accidentally introduced into Guam in late 1940s (potentially via a boat or plane).
• Huge population increases due to abundant prey and few predators.
• Caused local extinction of most small native forest vertebrates.
• Causes power outages as climbs over power lines.
• Venomous bite.
• Biosecurity measures are attempting to prevent further spread to other islands.

Question 7

Consequences of Anthropogenic threats: Population declines

Answer 7

• The living planet index (developed by WWF) is based on trends in more than 16,000 populations representing nearly 4000 species.
• Since 1970, the average population has declined by almost 60%.
• E.g. the biomass of flying insects in protected areas in Germany has declined by 76-82% over 27 years.

Question 8

Consequences of Anthropogenic threats: Extinction

Answer 8

• E.g. Tasmanian tiger died out in mainland Australia approx 2000 years ago, possibly due to human pressures. Hunted to extinction in Tasmania by British settlers and was declared extinct in 1936.
• 786 species extinctions recorded in past 500 years, many have obvious anthropogenic causes.

Question 9

Relative importance of threats:

Answer 9

• Habitat loss and degradation (including via pollution) = biggest threat amongst birds, fishes, reptiles and amphibians.
• Overexploitation is important, especially for fish.
• The importance of climate change is likely to increase. (Only 1˚C change, if increase to e.g. 4˚C then in combination with things like habitat loss, species can’t just move into a slightly cooler habitat).
• Invasive species and disease likely to increase due to global travel.

Question 10

Are we in the 6th mass extinction?

Answer 10

• 5 previous mass extinctions.
• All involve the loss of at least 70% of species, some up to 95%.
• Most appear to be caused by rapid global warming or cooling (suggesting climate change is going to be important)
• Rapid speciation often occurs after this.
• So far <1% of species have gone extinct but more are threatened with extinction. Not yet at levels seen in previous mass extinctions.
• If patterns of extinction carry on, 75% of species will have been lost in the next 240 - 540 years.

Question 11

We can change this:

Answer 11

• Most species still exist somewhere on earth + can be saved.
• Humans have solved major global problems in the past.
• E.g. DDT is a pesticide and concentrates as it goes up the food chain and causes problems particularly high up the food chain. It has been banned worldwide for agricultural use.
• E.g. SO2 emissions reduced leading to 65% decrease in acid rain
• E.g. hole in the ozone layer is healing after CFC use phased out.

Question 12

We can change this pt2:

Answer 12

• Now we have the biodiversity crisis. The greater one-horned rhinoceros was down to 200 individuals 20 years ago but now up to ~ 3500.
• We need to learn to live more sustainably on finite resources.
• If we fail, we will have caused one of the greatest periods of biological loss in the history of life on earth.