Conservation Biology & Wildlife Management

What classifies a mass extinction?

• In each of the five mass extinction events, 50% or more of marine species became extinct (this is what classifies them as mass extinctions).

How many mass extinctions has there been in earths history?

5-but you could say the 6 (Holocene) has already started.

Describe the Permian extinction:

• When.

• What caused it.

• Effects.

The Permian Extinction

• 252 million years ago.

• Likely caused by:

  • Extreme volcanism.

• The most severe mass extinction in Earth's history.

  • caused the extinction of about 96% of marine animal species and 70% of terrestrial species.

• Took 100 million years to recover.

  • More than the normal 5-10 million.

Describe the Cretaceous extinction:

• When.

• What caused it.

• Effects.

The Cretaceous Extinction

• About 66 million years ago.

• Likely caused by

  • a large asteroid impact

• Notably killed the dinosaurs.

How long does it take for the earth to recover after a mass extinction event?

• It typically takes 5–10 million years for diversity to recover following a mass extinction;

  • In some cases, up to 100 million years (Permian).

When did the sixth, human-induced mass extinction begin?

What is it called?

The Holocene Extinction

• Refers to the extinction of species during the present Holocene epoch.

• Started around 10,000 BC.

For these examples of species driven to near extinction or extinction by human activities; give when they went extinct.

• Bison

• Huia

• Passenger pigeons

These are evidence of the Holocene Extinction.

• Bison: By the late 1880s, the population was reduced to only 541 individuals.

• Passenger Pigeon: 1914.

• Huia: 1907.

Discuss the approaches of Conservation Biology vs Wildlife Management.

Conservation biology

• Management of nature and of earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions (Just cares about protecting nature from becoming extinct)

  
  Wildlife management

• Balancing the needs of wildlife with the needs of people, using the best available science

  (Also considers human needs)

What are the levels of biodiversity and why must it be considered at multiple levels?

Three levels of Biodiversity:

• Genetic

  • Genetic variation within a population and between populations.

• Species

  • Abundance of different Species and abundance of individuals in each species.

    • E.g. status classifications including extinct and critically endangered.

• Ecosystem.

  • Variety of ecosystems

They must be considered together as they are interlinked and affect each other.

• If ones harmed it will effect and harm the others.

There are processes through which natural systems help sustain life on Earth.

How much do these save as paying?

• In other words what is the global worth of ecological services is estimated to be?

125 trillion a year.

What is the single greatest threat to biodiversity.

Habitat loss and Degradation:

• Involved in 75% of species endangerment over past centuries.

Describe the small populations approach for conservation:

This approach focuses on the conservation of small populations, as they are more vulnerable to extinction.

• Small populations can experience inbreeding and genetic drift, which reduce genetic variability.

• This can reduce fitness (e.g., low fertility) or increase the frequency of harmful recessive traits.

Thus the approach is based on the extinction Vortex:

The Extinction Vortex: The key factor driving the extinction vortex is the loss of the genetic variation necessary to enable evolutionary responses to environmental change.

• Small populations will just keep getting smaller.

Define Minimum Viable Population Size (MVP).

• Minimum Viable Population Size (MVP): The population size at which a species can sustain its numbers and avoid falling into an extinction vortex.

Define Effective Population Size (N_e):

• What equation is used to calculate this?

• Breeding potential of a population. It incorporates the sex ratio of breeding individuals.

  • Total population size includes non-fertile individuals, which can make it look like there's more hope than there actually is:(

• Ne = \frac{4Nf Nm}{Nf + Nm}, where Nf and N_m are the numbers of females and males that successfully breed.

Define: Population Viability Analysis (PVA).

Incorporates the probabilities of all known risks to population persistence.

• It predicts the probability of population persistence through time

(Basic way of assessing different management tactics/what will work best for a population)

Describe the declining population approach.

• Focuses on species or populations that are declining, even if the species is far above its minimum viable population.

  • More cautionary than small pop. approach.

    • Also emphasizes the environmental factors that caused a population decline.