D4.2 - Stability & Change Flashcards
(23 cards)
stable ecosystems
ecosystems that can persist for long time w/out changing into another kind of ecosystem
stability depends on
constant energy supply
nutrient cycling
genetic variation within a species (survive selective pressure)
stable climate
disruptions include
removal of materials (deforestation)
removal of species (poaching)
eutrophication (too many nutrients)
climate change
tipping point
reaching level of disturbance that causes squick change difficult to reverse
tipping point in amazon rainforest - positive feedback loop
deforestation
less trees
less transpiration
drought
fires
mesocom
small replicates of ecosystems that allow for controlled experiements
advantages of mesocomes
replicates
easy
control factors
disadvantages of mesocomes
impossible to replicate all natural factors
keystone species
an organism that has a disproportionate effect in community
removal of keystone organism
makes the ecosystem collapse
sustainable harvesting
replacement must be greater than or equal to harvesting rate
sustainable harvesting of brazil nuts
do not harvest all crop
leave enough to grow new trees
sustainable harvesting of cods
protect breeding zones (no fishing)
increase net hole size (allow young to escape)
set harvesting limit
monitor population
factors affecting sustainability of agriculture
soil erosion (tiling causes soil loss)
nutrient leaching (eutrophication)
pollutants
carbon footprint
process of eutrophication
nirtogen and phosphorus rich fertilizers on farmland
run off into bodies of water
algae bloom on surface
block light
kill plants on bottom
decomposition consumes oxygen
increases BOD
BOD
biological oxygen demand
bioaccumulation
increase in toxin levels throughout organism life
biomagnification
increase in toxin level through trophic levels
macroplastic
large, visible waste
ingested by marine
entanglement
microplastics
small plastic fragments from the degredation of large pieces
prolific (found everywhere)
in animal tissues
effect to be determined
rewilding
removign effects of human intervention to allow natural processes to restore ecosystems
ways to rewild
stop human activities
reintroduce species (keystone)
distribute seeds of endemic plants
control invasive species
reconnect forests
rewilding hinewai reserve in New Zealand
farmland –> return to nativae forst
remove alien species
allow naturally occuring species to outcompete alien species
returnign habitat to original state
reducing human intervention (anti-management)
