Island biota and conservation Flashcards
(15 cards)
Case 1: Critically endangered Tristan Albatross
Mice were accidentally introduced to the island, most probably by sailors during the 19th century
In addition to developing bigger bodies in their few hundred years on the island, they have also developed an appetite for bigger food - the chicks of the nesting seabirds, which they nibble to death
Island biota
rich in endemics
Oceanic islands
ca. 3.5% of the worlds landmasses
ca. 15-20% of species on land
> 60% of extinctions on land
What is the mechanism/factor by which introduced species drive cascades of avian extinctions on islands?
Predation.
Predator driven extinctions: an island phenomenon
Island species a impacted by introduced predators because they have naturally few (or no) predators and ecological release
Island biota is characterized by..,.
Endemism
Dwarfism-gigantism
Extinctions
What do super generalist natives/endemics facilitate?
Establishment of introduced plants on oceanic islands
Species at risk of extinction due to natural hazards
ca. 70% of species at high risk of extinction due to natural hazards are on islands, especially on tropical islands
–> Island species threatened both by natural hazards and human associated activites
Island species and ecological functions perhaps more threatened on small, low-lying, isolated islands
Puerto Rican parrot
an example of human activity + natural hazards causing a near extinction
BUT captive breeding and translocations made it recover
The key to restoring island ecosystems
Removing introduced species
Redonda in the Caribbean
Invasive rats and goats removed to save the native wildlife
Mauritius
One of the worst cases worldwide regarding terrestrial biodiversity
Second country with the highest proportion of tress threatened with extinctions
Possible method of restoring island ecosystems
Reintroductions of extirpated or analogous species
election areas for protection, what do we consider?
Connectivity
Resilience
Edge effects
As many different species as possible
Endemics
Practicality of managements
Marxan - a near optimal solution for choosing protected areas
The best solution is the one with lowest costs and highest biodiversity gains but also dependent on boundary input (SLOSS)
No perfect solution in conservation planning
Summary: characteristics on island biota and conservation
Lots of endemics found nowhere else
Evolution in isolation –> susceptible to introduced predators
Lots of introduced species threatening native/endemic biota
Lots of extinctions and threatened species
Restoration possible, both by removing introduced species and reintroducing extirpated species or functional equivalent species
Captive breeding, translocations and protected areas
We can do better than we do today
