Lecture: Chapter 29 - Conservation Flashcards
Declining biodiversity
Rates of extinction are diffucult to measure because the number of species on Earth currently is unknown
Extinction rates determined from the fossil record are used as background rates
Vulnerable species
Much research on extinction has focused on problems of small populations, which are vulnerable to
Genetic events
Demographic stochasticity
Extinction vortex
A small population declines even further and becomes ever more vulnerable to process that lead to extinction
Endemic species
Occur naturally in a single geographic location. Particularly vulnerable
Extinction
A species becomes extinct when the last existing member of that speices dies
Migrations
Dependence on multiple habitats
Barriers: dams, fences, agriculture
Biodiversity Hotspots
Locations with proportionately high diversity
- high species richness
- endemism
Under threat from human activites
Primary threats to biodiversity
Habitat modification, invasive species, over exploitation, pollution, disease and climate change
Habitat loss
Conversion to an ecosystem to other use
Habitat fragmentation
Breaking up continuous habitat into patches amid a human-dominated landscape
Habitat degradation
Changes that reduce quality of the habitat for many, but not all, species
Overexploitation
As human populations increase and natural habitats shrink, the harvesting of many species from the wild has become unsustainable
Species exploitation
KIlling, poaching, fishing, domestication as pets
Population viability analysis (PVA)
Allows ecologists to assess extinction risks and evaluate management options
The probabilities of population persistence are calculated undrer various scenarios
Used to asses risk of extinction of a population
Minimum viable population
Smallest population that has a specific probability of being extant for a specific time period
