Community Ecology Flashcards
(144 cards)
1
Q
ecological succession
A
the sequential change in species composition of the community over time
2
Q
what are the two types of ecological succession?
A
- primary succession
- secondary succession
3
Q
what is primary succession?
A
initial establishment of plant and animal communities on substrates lacking living organisms
4
Q
examples of where primary succession occurs?
A
bare rock, lava, sand dunes, glacial melt water pond, rainwater
5
Q
why is alder the first species to grow after a landslide?
A
rock is nutrient-deficient, alder has nitrogen-fixing bacteria (hemlock do not) and can survive on the rocks.
6
Q
what type of plants can colonize rock after a landslide?
A
plants with nitrogen-fixing bacteria can colonize just rock
7
Q
what is secondary succession?
A
change of an established community
-> change in a preexisting community
8
Q
secondary succession: ponds and lakes accumulate _____, _____, ____, and get ______
A
- sediment, pollen, leaves
- shallower and smaller over time
9
Q
secondary succession: reeds, grasses and herbs develop on
A
shoreline
10
Q
in ecological succession, each sequential community is called a ______
A
seral stage
11
Q
_______ seral stages last longer than _____
A
successive, previous stages
12
Q
pollen has a ______
A
low decomposition
13
Q
it is possible to identify ______ taken from core
A
pollen species
14
Q
it is possible to estimate geographical age when plants died using _______
A
radiocarbon dating
15
Q
what are carbons three main isotopes?
A
C12
C13
C14
16
Q
C14 has a half life of ____ and decays to ______
A
5730 years, N14
17
Q
T/F: seral stages are well-defined by ecologists
A
false, depends on what you are interested in, even then it is pretty loose.
18
Q
how do we determine the hx of vegetation in secondary successive ecosystems?
A
pipe in ground (sediment cores)
- used to reconstruct vegetation hx
- when they find that C14 decayed to N14, that is their estimates for when the plants died
- can take the DNA of this plant and animal species
19
Q
ancient DNa reveal late survival of mammoth and horse in interior Alaska: what kind of DNa used?
A
sedaDNA - DNA from securely dated sediments
20
Q
explain the mammoth study:
A
found that mammoths lived until 10,500 BP, several thousand years later than indicated from macrofossil surveys.
- mammoth and horse survival overlap with humans
- contradicts the findings that extinction was due to extraterrestrial impact in late pleistocene
21
Q
put these in the correct order: bare ground, climax, pioneer seral stage, primary succession, serial stage, secondary succession
A
bare ground, primary succession, pioneer seral stage, serial stages, secondary succession, climax
22
Q
T/F: disturbance resets ecological succession back to the bare-ground stages
A
false, sets it back to any stage
23
Q
what are examples of disturbances that would set ecological succession back?
A
fires, melting glaciers, etc
24
Q
what is allogenic succession?
A
abiotic disturbances, such as fire, earthquakes, volcano (pushes back to earlier state)
25
what is autogenic succession?
biotic disturbances such as deaver ben
26
why is old growth important?
more biodiversity
27
in the summer after clear cutting, diversity is very _____, it then _____ before _______
high, plummets, increasing
28
immediately after clear-cutting, there are many _____, which means _____ is very _____. this is followed by a long period of _____
small shrubs (and small animals), diveristy, high, low diversity
29
in the winter after clearcutting, species ____ is very _____ for a long time. there is no _____ to _____ a winter _____
diveristy, low, old growth, support, habitat
30
diversity after clear-cutting is _______ dependent
season
31
after cleatcutting, biomass _____ immediately, then ____ to _____
drops, increases, aggradtation
32
aggradation
accumulation of sediment
33
total biomass peaks at _____, then ____ during the _____, before reaching a ready state
aggradation, decreases, transition
34
what causes total biomass to decrease during transition?
soil community
35
the soil community ____ after cleatcutting, then gradually ____ during aggradation. it is ____ once the community _____ because there is _____
dies, accumulates, lessened, stabilizes, less decomposition
36
soil is built by...
decomposition
37
how long to tropical regions such as Krakatau take to recover from primary succession to tropic forest?
100 years
38
how long would it take coastal bc rainforest to recover
- 1000 yrs for insect community
- 100 yrs for trees
39
how long would it take the arctic to reach late seral stages?
~10,000 yrs bcuz it is still changing
40
rate of succession is correlated to ____
temp and rainful
-> warm, wet habitat succession is fast
-> cool ,dry habitat succession is slow
41
what are the 4 ecological mechanisms for succession?
1. stochastic events
2. facilitation
3. inhibition
4. tolerance
42
stochastic events
largely unpredictable
- who gets there first can become established (by chance), major process in early seral stages
43
which ecological mechanism is most important in early seral stages?
stochastic events
44
facilitation
a species creates conditions favorable for a succeeding species but not itself
- eg. clover facilitates colonization of another species at the expense of itself (trees cover)
- leads to regular, sequential shift in species (assembly rules)
- major process in early seral stages
45
facilitation example
1. predators cannot colonize successfully unless prey are already present
2. pollinators cannot colonize successfully unless flowering plants are present
46
facilitation is ____, while stochastic events are ____
regular, unpredictable
47
facilitation events lead to reguar and sequential shifts in species, "______"
assembly rules
48
assembly rules example
predators cannot colonize successfully until prey are already present
49
inhibition
a species inhibits the colonization of subsequent colonists
- eg allelopathy: chemical inhibition (coral reefs), competitive exclusion
50
in inhibition, a species slows ____ and prolongs the ______
succession, seral stage
51
allelopathy
the production of chemicals by plants that inhibit the growth of neighboring plants
52
allelopathy is an example of____, it is common in ______
inhibition, plant communities (or coral reefs)
53
competitive exlcusion is an example of _____, it is common in _____
inhibition, intertidal communities
54
tolerance
members of a seral stage are those that co-exist due to the use of different resources
- combines facilitation and inhibition into a co-evolutionary view of succession
55
tolerance combines ____ and ____ into a _____ view of succession
facilitation, inhibition, co-evolutionary
56
'the ghost of competition past' refers to present _____
tolerance of species
57
species ____ among seral stages
change
58
in early seral stages:
_____ seed dispersal
_____ plant efficiency at low light
_____resource (nutrient) acquisition
good, low, fast
59
in late seral stages:
_____ seed dispersal
_____ plant efficiency at low light
_____resource (nutrient) acquisition
poor, high, slow
60
in early seral stages:
_____ biomass
_____ stability
_____ diversity
small, low, low
61
in late seral stages:
_____ biomass
_____ stability
_____ diversity
large, high, high
62
in early seral stages:
_____ species life history
_____ seed dispersal vector
_____ seed longevity
_____ shoot to root ratio
r, wind, long, high
63
in late seral stages:
_____ species life history
_____ seed dispersal vector
_____ seed longevity
_____ shoot to root ratio
k, animals, short, low
64
shoot to root ratio high vs. low seral stage
high in early, low in late stages
65
trophic levels
the sequence of steps in a food chain or pyramid
66
what are the 4 trophic levels?
- primary producer
- primary consumer
- secondary consumer
- tertiary consumer
67
what is the problem w trophic chain?
over simplified
68
a food web has many "_____'
chains
69
a food web has numerous '_______"
connections between chains
70
mean chain length
mean number of links running from a primary producer to each of the top predators
71
connectance
actual number of links in a food web divided by the total number of possible links
72
if a community has n species, then the total number of possible links (N) is:
N= n(n-1)/2
73
connectance equation
C=L/N
74
what is L?
actual number of links
75
linkage diversity
the average number of links per species
- total number of links divided by the total number of species
76
equation for linkage diversity
LD = L/n
77
how many types of trophic pyramids are there?
3
78
what kinds of trophic pyramids are theree
numbers, biomass, energy
79
umbrella (indicator) species
a species used for conservation decisions (grizzly bear, panada, spotted owl)
80
dominant species
a common species with an effect proportional to its biomass
81
zooplankton is a ____ species, while grizzly bears are a ____ species.
dominant, umbrella
82
keystone species
a species with an effect on the community that is disproportional to its biomass
83
examples of keystone species
sea otter, starfish
84
T/F: dominant, umbrella and keystone species never overlap
false, sometimes they do
85
where would 1. keystones and 2. dominants be located (below line/above line, top/bottom)
above line top, below line top
86
marine and terrestrial ecosystems: what is it called when nutrients move from terrestrial ecosystems to marine ecosystems?
downloading
87
marine and terrestrial ecosystems: what is it called when nutrients are moved from marine to terrestrial ecosystems?
uploading
88
how are nutrients downloaded to marine ecosystems?
rivers
89
how are nutrients uploaded to terrestrial ecosystems?
seabird guano
90
downloading leads to increased _____ in estuaries and _____ marine waters
primary productivity, adjacent
91
rivers discharge _____ to marine waters via downloading
sediment, trace elements, organic matter, nitrogen, phosphates
92
oligotrophic means
low productivity
93
clear and deep mountain lakes:
- oligotrophic
- N and P limited
- low plankton abundance
- usually few fish
94
migration of salmon greatly ____ of lakes and streams
increase primary productivity
95
why do clear/deep mountain lakes have few living things in them?
no trace elements
96
productivity of lakes are proportional to amount of.....
dead salmon that drift back
97
increase in _____ to abundance of salmon carcasses
productivity proportional
98
riparian zone
forest habitat adjacent to stream that is influenced by stream parameters
99
what are stream parameters?
flooding, nutrients
100
roughly what percent of salmon carcasses transferred by black bears into riparian zone at Bay Harbour were male?
33%
101
roughly what percent of salmon carcasses transferred by black bears into riparian zone at Bay Harbour were female?
66%
102
what part of the female salmon do bears like best?
eggs
103
what part of male salmon do bears dislike?
testes
104
during the day, bears mostly eat
females
105
at night, bears eat mostly
whatever sex they can catch
106
how do bears discriminate between salmon?
smell
107
productive condition of salmon captured by bears: average male salmon....
spawned 5-8 times before capture
108
productive condition of salmon captured by bears: female salmon...
70% were spawned out
109
most of the predation is on _____ salmon. therefore bear predation has a ____ on the reproduction of salmon
post-reproductive, minor effects
110
flow of salmon biomass: birds, sea lions, and seal eat salmon in _____
estuaries
111
flow of salmon biomass: bears, eagles, crows and insects eat salmon in _____
streams
112
flow of salmon biomass: marine invertebrates scavengers eat salmon that have
floated downstream
113
flow of salmon biomass: bears, small carnivores such as mink and insects eat salmon on the
forest floor
114
explain how salmon feed spring birds
insects lay eggs in salmon, hatch in spring, eaten by songbirds
115
nitrogen is a limiting resource for ____ in ____
vegetation, coastal forests
116
3& of total mass of salmon tissue is
nitrogen
117
salmon carcasses
in riparian zones contribute 120kg nitrogen per hectare
118
nitrogen
- 78% of earths atmosphere
- exists as 2 stable isotopes
119
14N
light isotope, 99.3% of total nitrogen (7 protons, 7 neutons)
120
15N
heavy isotope, 0.7% total nitrogen, 7 parts per thousand (7 protons, 8 neutrons)
- relative amount in biological systems varies
121
how are isotope ratios measured after the tissues have been collected?
washed, dried, and ground into a fine powder for combustion in a mass spectrometer
122
to determine how much of nitrogen is NOT from the atmospheres, we compare _____ _____ of tissues relative to _____ _____
isotope values, atmospheric standard
123
list in order of increasing d¹⁵N levels (lowest at top, highest at bottom):
bear
deer
phytoplankton/algae
salmon
small fish
trees/shrubs
wolves
zooplankton
trees/shrubs
deer
wolves
phytoplankton/algae
zooplankton
small fish
salmon
bear
124
15N values are higher in ____ waterfalls than ____ water falls
plants below, above
125
explain: what do waterfalls have to do with salmon?
salmon can't climb steep waterfalls
therefore salmon are below falls, not above them
126
nitrogen levels can affect
community structure
127
certain plants are found in nitrogen-rich soil and others are found in nitrogen-poor soil. what do we call these species?
indicator species
128
if salmon can't get over a waterfall, what kind of plant indicator species would you expect to find above the falls?
nitrogen-poor soil indicator plant species
129
if salmon can't get over a waterfall, what kind of plant indicator species would you expect to find below the falls?
nitrogen-rich indicator species
130
up to ____% of nitrogen in riparian plants is derived from salmon nutrients
80%
131
T/F: core samples show that the growth rate. of trees is due to the abundance of salmon
false
132
T/F: ¹⁵N levels for yearly growth rings show that the growth rate of trees is due to the abundance of salmon
true
133
if abundance of salmon affects tree growth, we will see _____ in the δ¹⁵N of trees ____ the spikes in salmon
lag, alter
134
how much nitrogen in feathers of songbirds is from salmon?
30-95%
135
30-95% of insect diet of winter wren is
salmon derived
136
salmon constitute about ___ of ____ diet of wolves
20%, fall
137
____ of bears 40x greater on ___ watersheds than on watersheds without ____
population density, salmon, salmon
138
___ are the major species that transfer salmon into ___ around the north pacific
bears, forests
139
each bear can transfer up to ___ salmon into the forest over a 6 week ____
500, spawning period
140
average transfer of ____ carcasses per km per year along ___ of river
1000, spawning reaches
141
up to 80% of the ____ in riparian plants come from salmon. this is an example of ____
nitrogen, marine-terrestrial ecosystem linkages
142
there is increased primary productivity and species diversity in watersheds with ___ and___
salmon, bears
143
salmon are a ____ species
dominant
144
bears are a ___ species
keystone
