12. How does overexploitation contribute to biodiversity loss Flashcards
what happens when we harvest too much
exploitation occurs
logging (cutting trees foor pulp)
hunting
fishing
hisotirc examples of overexploitation
extinction
hunters led to rhino, wooly mammoth, aurochs extinction
11,000 years ago, end of Pleistocene era
more than half of mammals in america disappeared with human first arrival in NA
how many genera of large mammals have gon extinct in NA in past 1000 years
34 genera
how is overexploitation different noow compared to before
accelerated
even for smaller species npw
what are majoorly affected species of birds
pigeons
most abundant before
hunted for food and commericialized`
passenger pigeon hypothesis
and its relation to mice and lyme disease
extinct
so dense before
ate acorn mast
important ecological role
harvesting of these led to mice populations explode
lyme disease increased as ticks get it from these mice and gave it to deers
tragedy. of the commons what is it
mechanism of how overexploitation leads to extinction
tragedy of the commons has explained…
alot of environemtal issues
a social dilemma
people use for self interest
coordination and limitation needede
overfishing - tragedy of commons
how many % of fish are overfished`
30%
hard to police in international waters
atlantic cod - tragedy of commons
better tech - deeper fishing
cod fishing became easier
stocks couldn’t recover
Newfoundland had to close this economic lifeline
catch was less too
make and break harbour
neewfoundland people reliance on fisheries, then fishes disappeared because over exploitation
by catch issue
non-coommerical species caught in nets
tossed overboard without caring
how many per cent of by catch is thrown back into the sea
25-75%
how to reduce bycatch
bird scaring lines
excluder devices
circle hooks
fine mesh aprons so dolphins excluded
freshwasher fishes are most affected by what and least by whay
most by invasive species
least by exploitation, still ha major effect though
which countries recreationally fish most
france UK Japan Mexico USA
logging and biodiversity loss
tropical harvesting leading too extinctions and extirpations for fuelwood
