Conservation Science Flashcards
Who proposed the classical model of island biogeography
MacArthur and Wilson 1963
What are the 2 patterns in island biogeography
- large island have more species than small islands
- near islands have more species than far islands
What processes cause these patterns
- extinction rate is higher on smaller islands
- the father the island the slower the immigration rate
What 3 types of islands are there
- Oceanic islands eg. Seychelles
- Landbridge islands eg. Britain
- Habitat islands eg. Forest surrounded by farmland
What is a meta population
As set of local populations occupying various habitat patches and connected to one another by the movement of individuals among them
What are natural boundaries (edges)
Areas of ecosystems that are near boundaries between different ecosystems which can provide unique habitats
Eg.:
- coastal forests in SA
- gallery forest, San Pedro river valley
What can man made boundaries (edged)
Road-forest
Forest-plantation
What is the drivers and passengers effect on ecosystems
Removing drivers causes a cascade effect but loss of the passengers leads to little change in the rest of the ecosystem (rivet popping hypothesis)
What is the insurance hypothesis
Increasing biodiversity insures ecosystems against declines
What is the idiosyncratic hypothesis
Ecosystem function changes when diversity changes, but the magnitude and direction of changes are unpredictable
What is ecological resilience
The capacity of an ecosystem to absorb disturbance without shifting to an alternative state
What model is used to describe ecological resilience
The rolling ball
What is the tipping point of an ecological system
When the stress put on an ecosystem passes a critical point and it shifts from one system to another becomes inevitable
What is social-ecological resilience
The capacity to adapt or transform in the face of changing social-ecological systems
What is the extinction vortex
The tendency of small populations to decline toward extinction once caught in a downward spiral
What happens to genetic diversity in isolated small populations
Decreases
What does inbreeding depression in carnivores lead to
Shorter life span, disease spread, reduction in offspring fitness
