D4.2 Stability and Change Flashcards
stability
the ability to maintain or support systems and processes continuously over time
requirement for stability in ecosystems
continual supply of energy, nutrient recycling, diversity of organisms and climate
what increases stability and how
complex ecosystems
increased number of niches
increases species and genetic diversity
tipping point
a critical threshold when even a small change can have dramatic effects and cause a disproportionately large response in the overall system.
equilibrium
state of balance among components of a system
changes are caused by
- human population growth
- resource consumption
- habitat transformation and fragmentation
- energy production and consumption
- climate change
what are most tipping points linked to
climate change
what would increase in Co2 lead to
increased global mean temperature
melting of ice and permafrost
amazon features
rainforest biome spanning over 9 countries
6 million km^2
1/2 of the planets tropical foresrs
why is burning and deforestation happening in the amazon
to make space for grazing land or housing, timber, illegal mining
fires are caused by
increased frequency of drought conditions
causes of deforestation
loss of large areas
prevents reestablishment of rainforests
what is a large area of forest needed for
generation of atmospheric water vapour
Percentage change for forest
[Change in forest / initial forest] x 100
mesocosm
Closed environment that allows a small part of a natural environment to be observed under controlled conditions
disadvantage of mesocosm
Studying natural ecosystems can be difficult because there are so many variables that can’t be controlled
advantage of mesocosm
able to control variables, except independent and dependent
both aquatic and terrestrial can be used
advantage of natural ecosystem
realistic
actual environmental conditions
disadvantage of natural ecosystem
Variable conditions
advantages of laboratory ecosystems
Able to control variables
disadvantage of laboratory ecosystems
Unrealistic and possibility of disputed relevance and applicability to natural ecosystem
eutrophication
The natural or artificial enrichment of a body of water, particularly with respect to nitrates and phosphates
natural and human causes
Example of things that cause eutrophication
Extra nutrients from fertilizer runoff from surrounding land
steps of eutrophication
High levels of nutrition for cave from fertilizer
Rapid growth
Block light to underwater plants that die
bacterial feed on these
Removal of oxygen from water
results in the death of many aquatic organisms
Keystone species
A species which has a disproportionate large effect on community structure relative towards abundance
example of keystone species
Agouti of South and Central America
Feeds or nuts of Brazilian nut tree
Hardwood species and among the oldest and tallest trees in the Amazon
only animal with teeth, strong enough to open the Brazil nuts, tree seed boards to access nuts
What would happen if Agouti werent there
Tree species would eventually die
Sustainability
The responsible maintenance of ecological systems so that there is no reduction of conditions for future generations, ensuring the long-term variability of a system
renewable resource
Continue to exist despite being consumed
replenish themselves naturally
terrestrial plant species as a renewable resource
Trees are renewable, provided they are replanted at the same rate as harvestation
what are trees used for
paper, cardboard, furniture, food, medicine, rubber
scots pine
1 of the 4 main logged trees
replanting needs to exceed number of trees act down
what to forests provide
important storage of carbon
marine fish
important source of food for many human population
use of fish
most populations are exploited commercially as food sources
harvested from common waters
overfishing of cod
cod led to a collapse of fish stocks
overfishing
if fish are persistently overfished, stocks will rapidly deplete till they collapse and can no longer support a commercial fishery
sustainable fishing practices
methods of catching fish that dont diminish the stock
MSY
maximum sustainable yield
maximum sustainable yield
maximum average catch that a stock can sustain over a long period of time
growing fish population is indicated by
having a larger number of younger fish
can indicate whether fishing methods are sustainable or not
physical factors affecting agriculture sustainability
precipitation
temperature
spoil
pests
location
environment factors affecting agriculture sustainability
pollution
habitat loss
reduction in biodiversity and soil erosion
soil erosion
process that can occur when the impact of water of wind detaches and removes soil particles, causing the soil to deteriorate
fertile soil
non renewable source
once depleted can take a significant time to restore its fertility
makes land available much lower now
leaching
the loss of water soluble nutrients from the soil
loss of nitrates
reduction in protien synthesis and growth in plants
agrochemical
a chemical used in agriculture such as a pesticide or a fertiliser
added to increase productivity
non biodegradable pesticides leads to
bio magnification
pesticides that are biodegradable are used to
minimize environmental damage
carbon footprint
the amount of Co2 released into the atmosphere because of the activities of a particular individual, organisation or community
what has led to an increase in carbon footprint
demand for unseasonal foods has increased the global transport of food, which has increased the carbon footprint
natural effects
nutrients being added from decomposing biomass and run off from idea
human causes for eutrophication
run off of fertilisers/manure, domestic waste water containing phosphates from detergents, non-treated sewage, leading of mineral nutrients
effects of eutrophication
- net primary productivity usually higher compared with unpolluted water and may be indicated by extreme algal or bacterial blooms
- diversity of primary producers changes and finally decreases
- length of food chain decreases due to algal
- algal bloom gives way to cyanobacteria which are toxic to wild animals
last effect of eutrophication
fish community gets dominated by coarse fish who can survive without oxygen
BOD
Biochemical oxygen demand
Biochemical oxygen demand
a measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity
BOD is affected by
number of aerobic organisms
rate of respiration
BOD is the difference between
the oxygen level of a sample of water initially and after 5 days at 20 degrees c
what affects food chains
non biodegradable toxins
increased concentrations
consumers feed on a number of organisms so accumulate toxins
cultivated crops
artificially selected to be high yielding
limited resistance to local parasites
pesticide
chemical that is used to control organisms that are a danger to crops or herds
have improved productivity but generated problems in the environment
DDT effect
causes rapid death even in low concentration
retained in fatty tissue of animals
bioaccumulation
the build up of non biodegradable or slowly bio degradable chemicals in the body
DDT
chemical substance becomes more concentrated
not recognised as a toxin and is not excreted
biomagnification
the process by which chemical substances become concentrated in the tissues of organisms at higher trophic levels
consequences of biomagnification
- accumulation of DDT
sparrowhawks
2000 clutches of eggs were measured
not nerve poison in birds and mammals - in breeding birds it inhibits the deposition of calcium in egg shell
macroplastic
relatively large, easily visible plastic debris found especially in the marine environment such as bottles, plastic bags, rubbish and other materials that have not degraded
microplastic
extremely small pieces of plastic debris less than 5mm in size, resulting from the breakdown of consumer products and industrial waste
macroplastics - food
can be confused with food by marine predators
bioaccumulate in the food chain
top predator at the risk because of biomagnification effects of some chemicals
albatross features
ranges across the north pacific
large birds with 2m wingspan
requires great quantities of fish
rest at midway atoll island
albatross in terms of plastic pollution
lots of plastic is washed up on midway atoll and they eat it
pick up plastic with fish and feed it to their chicks
impact on sea turtles
kills approx 100,000
mistake it for jelly fish and eat it
gets logged in their mouths
die of starvation
rewilding
restore ecosystems and reverses decline in biodiversity
reintroduces lost animal species to natural environment
keystone species also reintroduced
hinewai reserve
was completely cleared
ecological management involves minimal intervention, allowing succession to occur resulting in ecosystems
