Lecture 10 The EDGE of Existence

Question 1

Evolutionarily Distinctiveness

Answer 1

*Species which represent a larger amount of unique evolution = higher ED score

*Tree branches represent time since the origin of the group

*If branches connecting a species to the rest of the tree are shared with fewer species, a larger proportion of time is represented by each branch

Question 2

How do we determine if an organism is an EDGE species?

Answer 2

Global Endangerment:
*Based on the IUCN Red List Categories
*A higher ‘Threatened’ categorisation = higher GE score

*EDGE score = Evolutionary Distinctiveness + Global Endangerment

*EDGE species are species that have an above median ED score and are also threatened with extinction (Critically Endangered, Endangered or Vulnerable on the IUCN Red List).

*Species listed as threatened on the IUCN Red List with at least 95% confidence they have an EDGE score above the median for their taxonomic group

Question 3

How many EDGE species are there?

Answer 3

7784 amphibian species

11711 bird species

~900 coral species

5674 mammal species

Question 4

EDGE Zones

Answer 4

*Originally proposed in 2013, currently identified for all terrestrial vertebrates

*Highly irreplaceable areas containing disproportionately large amounts of EDGE species

Question 5

Why is considering evolution important in conservation? Phylogenetic Diversity indicator

Answer 5

*Tracks the overall status of the Tree of Life for different taxonomic groups through time.

*Measures the percentage of total evolutionary history within each group currently at risk of being lost due to extinction

Question 6

Why is considering evolution important in conservation?

Answer 6

*EDGE species can possess rare or unique characteristics important for their ecosystems, and/or provide benefits to humans

*‘Biodiversity option value’ –the maintenance of biodiversity is, in itself, beneficial to people as it will maintain the diversity of yet-to-be-discovered resource

Question 7

Predicting and quantifying extinction risk

Answer 7

*An integral part of how we prioritise species for conservation action.

*Good quality extinction risk data is available for only a small proportion of life on Earth.

*EDGE aim to support research that can improve extinction risk information to broaden the scope, and improve the robustness, of EDGE prioritisations

Question 8

Take-away messages

Answer 8

Scientists have defined an effective way of determining the amount of phylogenetic diversity that would be lost if a species went extinct

*Prioritising threatened species that represent a significant amount of unique evolutionary history will facilitate more efficient conservation efforts

*EDGE species form an integral part of our global ecosystem and human lives

*More research is needed for Data Deficient species