Ecology - Abundance And Distribution Flashcards
Define uniformly distribution
Occurs when resources are evenly spread or when individual of a specie are hostile to each other
Def clumped distribution
Groups of plants or herds of animal depend on specific resource will be in an area where resource located
Random distribution
Plenty of resource and no competition
Quadrants
Used to sample slow or non mobile organism
Quantitative measuring
Can calculate percentage cover or do individual counts
How to do quadrants
1) place 2 tapes measure at right angle to create a graded area to take sample from
2) use a random number generator to generate coordinates to take sample from
3) place quadrants on the coordinates + either count the abundance of the specie or calculate percentage cover
4) repeat at least 30 times
Limitation of quadrants
Limitation of sample area
Random ness of the sampling
Decision made about whether to include organism or exclude partly covered by the quadrant
Limitation of ACFOR
Is a subjective scale;two ppl will not get the same results
No set definition for terms
Species can be rated to how easily they are spotted not abundant
Transect
Systematic sampling
Seta tape between two points record every individual that touches the tape
Belt transect
1) tape measure placed through a non uniform ecosystem
2) quadrant placed at intervals along the transect to measure the impact of changes in the environment
What do you use to measure the temperature
Glass/digital thermometer
Thermistor
What do you use to measure light intensity
Light meters
What do you use to measure pH
pH indicators
pH meters
What do you use to measure the wind speed
Anemometer
What do you use to measure the slope of incline
Clinometer
What do you use to measure the oxygen (in water)
Digital oxygen probe
Primary succession
1) a pioneer specie colonise bare rock or sand
2) pioneer specie are adapted to survive harsh abiotic conditions and change the abiotic factors to become less harsh through death and decomposition
3) moss and smaller plants can now survive and they further increase depth and nutrients density of the soil as they die
4). This continues and larger plants can survive c further change the environment
5) each new specie May change the environment in a way that th eprevious specie can no longer survive as they become out-competed
6) these changes result in a less hostile environment and increases the biodiversity
7) final stage of succession is a climax community
Primary succession step 1
Pioneer specie can withstand harsh conditions and germinate easily
As the pioneer specie die and decompose the dead organic matter forms the soil
Primary succession step 2
Seeds of the small plants and grass on this soil begins to grow and adapted to survive in shallow , nutrients poor soil
—> the roots fo these small plants form a network that helps to hold the soil in place and prevent it from being washed away
Primary succession step 4
As the small plants die and decompose the soil becomes DEEPER and more nutrients rich
Primary succession step 5
Larger trees and shrubs as well as small trees can grow —> require more water and stored in the deeper soil
Primary succession step 6
Over time the soil becomes sufficient deep and contains enough nutrients and hold enough water to support the growth of large trees
—> final specie to colonise of new land become the dominant specie of now complex ecosystem—> climax community
Define succession
The process by which organism colonising an area change over time
Define colonisation
The process by which new specie spread to new area
Define pioneer specie
Specie which are first to colonise new or disturbed ecosystem
Define climax community
Self sustains community with relatively constant biodiversity and specie range
It is most productive group of organism that a given environment can support long term
Define plagioclimax
Climax community that is least in part the result of human intervention
How does human prevent climax community from developing
Regular mowing prevents woody plants from establishing themselves in a lawn
The grazing activity of livestock
How does the pioneer specie help break down the top surface
Lichens help slowly break apart the top surface of bare rock this fragmented rock along with the dead organic matter left behind when the lichens die and are broken down forms basic soil
What does grasses do
Grasses grow roots that stabilise the soil enabling it to hold more moisture and nutrients
