complete solutions
what are the 3 ecosystem threats - correct answer ✔✔ - Invasive species
- Overexploitation
-disease
What are some examples of Overexploitations - correct answer ✔✔ - commercial harvesting
- Bushmeat trade
-international wildlife trade
What are some examples of Overexplotations
- Commercial harvesting - correct answer ✔✔ Ymax = MSY
- Ymax occurs when the population size is at about hald the carrying capacity of when biomass
is half of its max value
- MSY = rK/4
k= Carrying Capacity
r = intrinsic rate of 'stock' growth
if r has a value of 2 the population is capable of double every year till K is reached
Overexplotations
- Commercial harvesting
Problems with MSY - correct answer ✔✔ 80% of the worlds fish stock classified as over fished
why ?
- difficult to coordinate catches across internatioinal boundaries
,- illegal catch not accounted for
- large portions of juvenile populations can be damaged during harvesting operations
Commercial harvesting - what is Bycatch ? - correct answer ✔✔ Marine birds that are trapped in
nets, or other fish species that are not desirable, killed for no reason
solution
- an adoption of gillnet gear modification to reduce seabird bycatch
What are some examples of Overexplotations
- International wildlife trade - correct answer ✔✔ primates 70,000 used in biomedical research
birds 250,000 zoos and for pets
retiles 1,000,000 zoos and pets, but also used for skin
Define - International wildlife trade - correct answer ✔✔ defined as the sale or exchange of any
wild animal or plant (including trees), one might also finger both a rising population and sharp
increase in the globalization of commerce over the same period.
what are some solutions for Overexploitation ? - correct answer ✔✔ - Conservation projects
increasingly linking conservation of biodiversity and local economic development
- acknowledging sustainable harvesting of a natural resource with special certificates
- parks, reserves and sanctuaries
- Enforcement of international regulations such as CITES ( the convention on international trade
in endangered species of wild fauna and flora)
What prevents species from dispersing globally ? - correct answer ✔✔ geographical barriers
- oceans, mountains, deserts, large lakes
, what are the 6 global biodiversity realms - correct answer ✔✔ Nearctic
neotropical
ethiopian
paleartctic
oriental
australasian
they are characterized by their different flora and fauna
How were some species introduced - correct answer ✔✔ - European colonization
-Agriculture, horticulture, and aquaculture
Invasives sold for cultivation practices
-Bait dumped by fishermen (European Earthworms in the boreal forest)
-Transportation of goods
- Biological control (Cane Toad introduced to control beetles, toads are toxic to native species
and invaded native range)
Invasive species - correct answer ✔✔ organisms that become established outside their natural
range, and spread and increase in abundance rapidly
- implies exotic/introduced/alien and a threat to native species and ecosystems
Exotic species - correct answer ✔✔ occurring outside of their natural ranges because of human
activity
introduced species - correct answer ✔✔ introduced but not a threat to native species