13. Biotic And Abiotic Interactions

Question 1

What are the main physical conditions that may effect distribution?

Answer 1

Temperature, geology

Question 2

Where might different mesohabitats be found in a stream?

Answer 2

Mud, river channel, snags

Question 3

What are the two forms of competition?

Answer 3

Inter specific and intraspecifc

Question 4

What is exploitation competition?

Answer 4

Where food or space are limited?

Question 5

What is interference competition?

Answer 5

Aggressive interactions between competitor species individuals

Question 6

How can competition be reduced?

Answer 6

Resource partitioning

Question 7

How does hydropstchidae avaoid competition

Answer 7

Different species live in different areas of the stream

Question 8

Where can microhabitat partitioning take place?

Answer 8

Ok or around rocks and boulders , different points of the rock can harbour different species

Question 9

What happened when glossoma was reduced?

Answer 9

Baetis increased

Question 10

What do the relative numbers of herbivores depend on?

Answer 10

The success of others, competition

Question 11

Name a net spinning caddis?

Answer 11

Hydropsychae

Question 12

How did fish use resource partitioning in the Mississippi?

Answer 12

Areas with vegetation and depth impacted where most species lived

Question 13

What are the main aquatic predators?

Answer 13

Fish

Question 14

What insects can be predators

Answer 14

Dragon flies, stone flies, choronomidae. Basically lots of flies

Question 15

How do predators select their prey?

Answer 15

Size, activity, visibility

Question 16

What are the 2 main prey mechanisms to avoid predation?

Answer 16

Capture and encounter

Question 17

Where might prey hide in a stream

Answer 17

Creveses in the rocks, move into the hyporeheic zone

Question 18

How do prey reduce captive rates?

Answer 18

Detect and flee- precontact, armour, aggressive traits, playing dead-post contact

Question 19

What do daphnia produce to reduce predation by fish?

Answer 19

Helmet horns

Question 20

Which insect uses fast swimming to escape predation?

Answer 20

Baetis

Question 21

What is a common adaption to reduce predation in stream organisms?

Answer 21

Camouflage, a lot of insects are the colour of their environment

Question 22

What is Aposematism

Answer 22

The use of extreme colour to warn predators, colour can be linked to foul taste or chemicals

Question 23

Which garden insect can taste unpleasant and can release a toxic substance?

Answer 23

Lady birds

Question 24

How does the water strider vary spatially?

Answer 24

Only in vegetation when fish are present and only out in the open when there are no fish

Question 25

What animals can change their development rate so that they emerge smaller when more fish are present?

Answer 25

Mayfly

Question 26

What is training bias?

Answer 26

When fish only feed on one species of insect as they know this one is safe

Question 27

What has been said about control in the trophic system?

Answer 27

Areas of top down control, animals at the top control those at the bottom

Question 28

What Does herbivory do to peripyton?

Answer 28

Reduces it

Question 29

What else does herbivory do?

Answer 29

Influences community composition, opening up areas for other species

Question 30

What happens to algae with grazing pressure?

Answer 30

Their photosynthetic rate increases with pressure

Question 31

What is the harsh benign concept?

Answer 31

A gradient in streams

Question 32

What does harsh mean according to peckarsky?

Answer 32

Few competition predation effects

Question 33

According to peckersky? | What does benign mean?

Answer 33

Environments allow for well developed competition

Question 34

What is disterbance?

Answer 34

Relatively discrete event in time that removed organisms and opens up space that can be colonised by individuals

Question 35

What is an example of a common disaster in a stream?

Answer 35

Flood

Question 36

What is the intermediate disturbance hypothesis?

Answer 36

We expect to find the highest level of diversity in middle levels of disturbance

Question 37

What is the patch dynamic concept?

Answer 37

Disturbance opens up patches for new colonisers

Question 38

What is another name for fugitive species?

Answer 38

Ruderal species

Question 39

What species will be dominated by good competitors?

Answer 39

Stable systems like large rainforest rivers

Question 40

What systems do fugitive species dominate?

Answer 40

Small flashy unreliable habitats

Question 41

How can patches be created though biological activity?

Answer 41

Salmon redds

Question 42

How can nuphar lutea create more habitats

Answer 42

Reducing flow, deposition of sediments

Question 43

What effect can crayfish have on systems?

Answer 43

Clean gravel, larger supply of FPOM

Question 44

How much can blackflies reduce flow in water?

Answer 44

75%less flow after 60mm

Question 45

How do hydropsyche make room for mayflies?

Answer 45

The reduction of flow

Question 46

What are reciprocal subsidies?

Answer 46

When one environment is benefiting the other

Question 47

Why does it take longer for salmon to move into newly formed streams?

Answer 47

They normally only go back to the stream where they were born

Question 48

When happens do adult salmon when they go back up stream?

Answer 48

They die, massive release of nutrients

Question 49

How is the salmon carcus used?

Answer 49

Different parts of the salmon used by different animals, bears eat the heads

Question 50

What caddis fly can expand to huge numbers to feed on salmon carcass?

Answer 50

Ecclisomyia

Question 51

What happens after the bears are finished with the fish?

Answer 51

Leave bits of the carcass or defecate out

Question 52

How can tree rings link to salmon abundance?

Answer 52

The more salmon the thinker faster growing the tree is

Question 53

How many insects are there in summer streams per meter squared?

Answer 53

250mg

Question 54

When are terrerestrial invertebrates more important?

Answer 54

The summer

Question 55

When do most fish feed?

Answer 55

The afternoon

Question 56

What is Allen’s paradox?

Answer 56

Trout consumed 30x more biomass than what was available in the stream, in the summer 60% can be invertebrates

Question 57

What else can eat stoneflies

Answer 57

Ground beetles, 80% of diet

Question 58

What impact does predation by beetles have on the river system?

Answer 58

Less egg laying, control of the environment

Question 59

What is Thanotaxis?

Answer 59

Playing dead

Question 60

What is another name for a micro habitat?

Answer 60

Meso habitats

Question 61

Who came up with the patch dynamics theory?

Answer 61

Townsend

Question 62

What is patch dynamics?

Answer 62

Disturbances continually opening up patches that are colonised