FEM Flashcards

(127 cards)

1
Q

what is a disturbance

A

a sudden event in that time that removes biomass, disrupts ecosystem- community- or population structures and causes a rapid release or reallocation of environmental resources such as light, water or soil nutrients.

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2
Q

key aspects of disturbance

A

size, frequency and intensity

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3
Q

what should forest managers attempt? (in context of disturbances)

A

minimizing deleterious changes while maintaining future stand productivity and management options

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4
Q

what does harvesting intensity influence?

A

stand basal area, and in turn canopy cover and thus light availability

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5
Q

what are the two harvesting systems?

A

monocyclic (clearcut, all standing timber cut at once) and polycyclic (limited proportion of stems is cut)

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6
Q

what does monocyclic regenration depend on?

A

seed bank

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7
Q

what does polycyclic regenration depend on?

A

advanced regeneration, also called seedling bank

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8
Q

what is difference in canopy gaps between harvested and natural forest?

A

natural: small and quickly filled by advanced regeneration.
harvested: bigger and higher density. domineered by pioneer vegetation

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9
Q

what trees are found in logging roads?

A

pioneer species

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10
Q

consequences of too big canopy gaps?

A

soils drying out, nutrient loss through run-off, and herbaceous vegetation interfering with regeneration. And lots of regrowth may attract deer or other animals which damage regrowth and maintain open areas.

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11
Q

transformative change

A

not continuing business as usual, and radically changing our ways

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12
Q

forest-transition curve

A

forests are first lost for agriculture and then abandoned so the forest returns

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13
Q

how to achieve transformative change according to IPBES (international panel for biodiversity and ecosystem services)

A

formulate policies with the highest leverage (impact for action). Including reducing consumption, investing in technological solutions, shifting focus from economic welfare to human welfare

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14
Q

what is the role of soil in biogeochemical cycling

A

regulate fluxes of carbon, water and nutrients, and belowground storage

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15
Q

Mor soil

A

poor and infertile. Only an ectorganic layer (i.e., litter on top of the mineral soil).

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16
Q

Moder soil

A

intermediate fertility. Ah horizon (Layer where the mineral soil is mixed with humus), with darker humus incorporated in the mineral
layer.

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17
Q

Mull soil

A

rich and fertile soil. A deep Ah horizon (Layer where the mineral soil is mixed with humus) well, mixed, with a lot of bioturbation

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18
Q

how do above-below ground linkages differ

A

between fast (fertile soils) and slow (poor soils)

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19
Q

fast species (fertile soil)

A

thin, productive leaves with high nutrient value.
support high herbivore density. leaf litter layer high in nutrients and low in defense, bacteria and earthworm based decomposition. low net carbon accumulation and fast leaky nutrient cycling

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20
Q

slow species (poor soils)

A

long leaf life span, high defense, fungi and arthropod based decomposition, slow nutrient cycling and high carbon storage

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21
Q

3 drivers of decomposition:

A

litter (quantity and quality),

environment (conditions that speed up decomposer metabolism and activity)

decomposers (bacteria/macrofauna or fungi/microarthropods and what they can decompose).

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22
Q

Definition of decomposition

A

process where dead organic material is broken down into simpler organic or inorganic substances, such as carbon dioxide, water, simple sugars and minerals.

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23
Q

where is leaf litter production highest?

A

tropics, lowest in poles

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24
Q

where is leaf litter on forest floor highest?

A

poles, lowest in tropics

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25
what is the most important predictor for decomposition rate?
tree species (more important than climate)
26
how many european specieds are associated with dead wood
one third
27
The LOGlife project
an experiment to see how different tree species differ in decomposition rate.
28
which dead trees host the most fungi?
broadleaved trees and species with acquisitive stem traits (high nutritional value and low defense)
29
bring back the lime forest
To make the old growth flowering herbs come back, it’s proposed to plant trees with liming properties on intermediate soils to make soils richer.
30
Environmental heterogeneity in forest is influenced by:
tree and branch fall disturbances which create gaps in the canopy and therefore different conditions on the forest floor.
31
which nutrient is lost with leaf fall?
Ca, because it can't be reabsorbed
32
use of Mg for plants
crucial component of chlorophyll, therefore important for photosynthesis
33
use of Ca for plants
integral component of cell membrame and cell wall
34
use of K for plants
important for enzyme activity and stomatal regulation, and thus for carbon gain and water loss
35
how can environmental factors influencing plants be classified?
resource, condition or signal
36
resource
consumable substances (nutrients, light, water etc)
37
condition
: environmental factors that are not consumable but affect the efficiency of resource use. (soil pH, temperature)
38
signal
conditions that influence plant development, but not via resource use. For example plants can detect low light conditions which will trigger inhibition of seed germination and growing longer stems.
39
When is a forest heterogeneous?
Depends on your question, what scale? Seedling, cellular or community? And over what time? Centuries, years, hours?
40
two types of heterogeneity:
anthropogenic/measured and phytocentric/functional.
41
6 ways to describe heterogeneity
quantity, frequency distribution, thresholds, timing or location, pattern and congruency.
42
heterogeneity frequency distribution
frequency of something being available for a plant through time, eg how many minutes a day does light reach a leaf
43
heterogeneity duration of time above thresholds
many processes are regulated by time spend above a certain threshold.
44
heterogeneity timing or location
the timing and/or location of threshold events has an impact on the ecology of a forest. A drought in the beginning of the growing season will be different effects than later in the season. Drying in the upper part of the soil has different effect than drying of root systems
45
heterogeneity pattern
which patterns exist within a forest or patch may be an ecologically important component of heterogeneity.
46
heterogeneity Congruency of environmental factors
environmental factors occurring at the same time and place. The factors can also influence each other.
47
heterogeneity Quantity
most used to measure environmental heterogeneity. Total or average level of a resource or factor.
48
when do you want less heterogeneity
if you have a monoculture timber plantation
49
photosynthetically active radiation (PAR) or photosynthetic photon flux density (PPFD)
light on the visible light spectrum that platns can use for photosynthesis
50
When light hits vegetation, it can be:
reflected, absorbed or transmited (transmittance of the radiation that passes through the leaf and is not absorbed)
51
You can describe light from three aspects
quantity, quality and light distribution over time
52
quantity of light
how much light reaches a plant
53
quality of light
plants need red light for photosynthesis. Other light is not intercepted, such as far-red light. When light is intercepted a lot by plants that cast a deep shade the red light reaching below is less than when a light shade plant hangs overhead. Or, the R:FR ratio is higher. This ratio can thus tell us how dense foliage is.
54
periodicity of light
light periodicity is variable in different time scales. For example in the tropics there is not much seasonal change, but on a shorter time scale sunflecks become important. Sunflecks are temporal patches of direct radiation due to unobstructed sky (no clouds or overtopping vegetation)
55
what are lag times?
light affects processes at small time and space scales, but it takes longer before bigger effects are seen. They are basically always lagging behind. so it can take a long time before effects of silvicultural treatments are seen,
56
three main gradients in forests
horizontal (from understory to gap center) vertical (from floor to canopy) center-edge
57
three main causes of sucession:
availability of open sites, differential species availability, defferential species performance
58
drivers/conditions for availability of open sites
disturbance
59
drivers/conditions for differential species availability
dispersal and propagule pool
60
drivers/conditions for differential species performance
resource availability, ecophysiology, life history, interactions, herbivory
61
definition of succession:
different ones, in course guide: a progressive alteration in the structure and species of the vegetation
62
pickets way to describe sucession:
pathways (temporal pattern), mechanisms (interaction or process that contributes to sucession, eg dispersal, competition) and models (conceptual map that explains a pathway and which mechanisms are important in different stages)
63
key points to clements succesion theory:
plant community is an organism deterministic autogenic progressive and irreversible ends in mono-climax
64
what is the climax according to clements
a mono-climax that maximum stability that resists change, all sucession in the same climatic region leads to the same climax
65
key points to gleason succesion theory (individualistic theory):
-individualistic, plants are individuals -no sequential vegetation changes, just vegetation that contineously replaces each other -species composition due to chance (availability) so no orderly process -coexistence because of overlapping niches -reverseble and regressive -no definite climax
66
gradient from understory to gap centre
short and unpredictable, from little light to more light. variation in light and soil temperature increases. litter higher in recent gaps and less in older gaps.
67
fallen tree gradient
root, bole and crown different regenerational niches. root gives good germination small-seeded species. bole also gives a good head start for species, especially when forest floor is densely populated. the crown has high nutrient and gives protection from herbivores, but can smother seedlings with lianas or scramblers
68
south-north gradient in a gap
in northern hemisphere the sun is always in the south which leads to more sun in the north.
69
west east gradient in gap
west receives light in the morning when temp is low and humidity and co2 is high. this gives good growth conditions. East receives light in the afternoon when vapor pressure deficit is high leading to plant stress
70
vertical gradient
along the height gradient, light availability, air temperature, vapor pressure deficit and windspeed increase and relative humidity decreases
71
what happens with co2 concentrations in a forest
they are much higher than outside of the forest
72
how to increase biodiversity
create horizontal and vertical gradients, create gradual transition from forest to matrix in temperate regions, and sharp transition in tropics.
73
relay floristics sucession
clear sucessional stages, sequential replacement. one group modifies the environment so the next takes over.
74
initial floristic compostion model
all species are present in the initial stage of sucession, and then occurr as seperate stages over time
75
polyclimax
for any combination of environment and organisms there will be a climax, but what that is depends on environment and biotic conditions
76
gradational climax
different climaxes exist along major environmental gradients
77
site climax
climax can only be classified at site level because it depends on local conditions and environmental gradient
78
primary sucession
occurs on previously unvegetated terrain
79
secondary succession
occurs on previously vegetated terrain, where a disturbance has removed part of the biomass and species, but some legacies are left
80
secondary sucession phases according to Peet
establishment, thinning, transition, steady-state
81
secondary sucession phases according to Oliver
stand initiation, stem exclusion, understory reinitiation, old growth
82
cyclic succession
forests are a mosaic of patches in different phases of micro succession or forest development. also called forest growth cycle.
83
forest growth cycle
also called cyclic succession or silivgenesis. four phases: gap, building, mature and degenerate
84
four phases of cyclic succession accoridng to Watt
pioneer, building, mature, degenerate (and back to pioneer).
85
how much forest loss is in the tropics
90%
86
what happens with species in secondary forests
recovery in species richness takes decades, species composition centuries
87
what is difference between wet and dry tropical forest regarding sucession
oppsite in wood densities: wet have pioneer with low wood density and dry with high.
88
three indicators of forest recovery sucess
maximun tree height, structural hetergeneity, species richness
89
what determines disturbance impact
size, frequency and distribution
90
what disturbances lead to primary succession
volcanoes, landslides, meandering rivers, driftsands
91
what disturbances lead to secondary succession
fires, floods, droughts, pests, wind
92
most typical disturbance in forests globally
tree and branch falls
93
regeneration gradient along increasing gap size
branches -> advanced regeneration -> sprouts -> seed bank -> immigrants
94
what drives seed limitation (not all seeds being able to colonize new areas)
source-limitation (not enough source trees, or non-productive source trees) and dispersal limitation (e.g. too little wind, to few animals for dispersal, uneffective dispersal method)
95
what does seed limitation promote
species coexistance and diversity, it can slow competitive exclusion as the stronger species may not arrive to the site.
96
polycarpic/monocarpic
wether reproduction is continuous or a one time event for a species
97
hermaphroditic
produce bisexual flowers. majority of tropical species.
98
monoecious
male and female flowers on the same plant. relatively rare, palms, figs and euphorbiceae
99
diocious
seperate male and female trees. more common in tropics than temperate forests.
100
why would a tree reproduce early?
fast growing pioneers and understory species are at a high risk of being outcompeted or dying (due to tree/branch fall) so it's best to reproduce early
101
why would a tree repdroduce late?
better acess to light and better resources for reproduction
102
how do trees disperse seeds?
in tropics mostly animal pollinators, in temperate more wind. conifers are all wind pollinated, if they're in the tropics they tower above the other trees
103
pollination syndrome
a similar set of traits in in florescence (flower tros) and flower morphology and presentation, attractions and rewards that attract certain pollinators
104
Pollination syndrome bats
mostly tropics. bat flowers open at night, have large petals and produce much nectar. often well exposed and cauliflorous (growing on trunk)
105
Pollination syndrome insects
bee flowers smell sweet and ar nectar rich. moth flowers are nocturnal commonly pale, sweet scented and a long corolla tube.
106
Pollination syndrome birds
often vivd red
107
rhizoflory
flowers growing from roots of tree, to attract understory dwellers to disperse seeds/pollinate.
108
four main agents of seed dispersal:
wind, animals, gravity and water
109
anemochory
wind dispersal
110
ornithochory
bird dispersal
111
what are characteristics of mammal dispersed fruits
none
112
chiropterochy
bat dispersal. usually green fruits
113
piscichory
fish dispersal.
114
hydrochory
water dispersal
115
barochory
gravity dispersal
116
secondary dispersal
fruit that first falls, and is then dispersed by animals
117
three ecological advantages of investing in efficient dispersal system for plants
colonization of new habitats, directed dispersal and escape
118
what happens to seed mortality away from parent tree
it decreases, as there are less predators
119
Distance and density dependent mortality (DDD)
seeds dispersed farther from mother tree have a greater chance of escaping predators (insects and pests) and thus higher survival chance
120
two main ways of regenerating
sexual (generative, regeneration from seed) and asexual (regeneration from vegetative sprouting)
121
what is a plant strategy
combination of traits leading to similarities in species ecology
122
fundamental niche
where a species could theoretically occur
123
realized niche
where a species actually occurs.
124
distinct preference niche
realized niche smaller than fundamental niche, realized niche in center (in graph)
125
shared preference niche
all species share an optimal fundamental niche, there is a trade of between dominance and environmental tolerance. realized niche is only in center for dominant species. most likely and often best niche model for trees
126
what are four different crown classes that competition leads to
dominant, codominant, intermediate and surpressed
127