7: Threats to Biodiversity pt 2 Flashcards
What is actor caused?
Originating from a discrete group/individual(s)
What are the actor-caused agents of extinction?
Exploitation, invasive species, disease dynamics
What groups were traded the most in 2017? What about reptiles?
Orchids (35 million)
Cacti
Reptiles were at 15.6 million in 2013, but dropped significantly bc they are being ‘backyard bred’
What is the logic harvesting model equation
dN/dT = [rN((K-N)/(K)] - qXN
qXN = amount of fish removed from pop via harvesting
q = catchability
X = fishing effort
What is carrying capacity
Resource availability limits growth rate so species reach a max population size
What is maximum sustainable yield
The amount of a pop can be taken in perpetuity
What is the issue with maximum sustainable yield (MSY)
Considers stocks of individual species as single/isolated biological units rather than components of a larger ecological system (overlook need to leave behind certain portion to continue ecological role)
Example of when there is no concept of MSY
Bushmeat trade in Africa (primary source of protein for many Africans (30-80%))
Causes of the bush meat crisis (7)
Poverty, food insecurity, increased access, increased demand, few protein and income alternatives, ineffective policy/law enforcement, limited awareness
Effects of bush meat crisis? Solutions?
Decline/extinction of wildlife species
Loss of culture
Risk of diseases (ebola, anthrax, tuberculosis)
Education (youth, health risks), provide alternative livelihoods/food
What do we mean by ‘fishing down the food web’
Resources becoming more rare or extinct, market turns to another species
Use fish at lower trophic levels
Two examples of invasive species
Zebra mussels: collapse ecosystems
Lionfish in the Caribbean: has excellent defenses and is a predator
Example of invasive native species? How do they become invasive?
Rainbow trout
Often due to interaction with habitat fragmentation or other form of degradation
How is disease a conservation threat
Contributes to pop decline but rarely extinction (3%)
Interacts with other threats (invasion, habitat loss/degra, overexploitation)
What parasite are urban coyotes getting? How does this affect them?
Echinococcus multilocularis (very common in edmonton 65%)
Causing more conflict behaviour (more hungry = increase in human interactions)
