Lecture 3 - Landscape Ecology & Watershed Management Flashcards

1
Q

How does the surrounding landscape influence an ecosystem?

A

Through:

  • erosion
  • eutrophication
  • habitat
  • water quality
  • water temperature
    ex. the characteristics of a stream in forest very different than that of a stream in agricultural land
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2
Q

What is an example of how organisms can influence their landscapes just as much as landscapes can influence organisms?

A

Beavers! They are a keystone species as they build dams that can completely change a landscape

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3
Q

Who are 3 people that influenced the creation of landscape ecology?

A
  • Carl Troll: studied aerial photographs for changes
  • Aldo Leopold: looked at patterns and animal pops
  • Alexander Watt: studied plant communities
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4
Q

What are the main factors that effect landscapes?

A
  • topography
  • surface geology
  • geomorphology
  • natural disturbances
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5
Q

How does topography affect landscapes?

A

It is the basic cause of landscape patterns.

Ex. alpine tundras only occur in high elevations while riparian vegetation only occurs along streams.

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6
Q

How does geology affect landscapes?

A

It affects the soil type and vegetation distribution.

Ex. glaciation plays large role

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7
Q

How does geomorphology affect landscapes?

A

It shapes a landscape through:

  • landslides
  • erosion
  • sand dunes
  • permafrost
  • fluvial dynamics (creating meandering rivers that are always changing)
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8
Q

How do natural disturbances affect landscapes?

A

It abruptly alters vegetation.

ex. fire, wind, insects, animals

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9
Q

How does fire affect landscapes?

A

It is natural part of taiga and certain vegetation depends on it - it creates a characteristic landscape.
It is also necessary for regeneration and creates patchy mosaic forest habitat

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10
Q

How does wind affect landscapes?

A

Different patterns are created depending on wind type (wind can blow down all or only portion of trees).
Also, hurricanes are wide, so they can take down more than tornadoes can (thin).

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11
Q

How do insects affect landscapes?

A

The outbreak of tree defoliating insects is very damaging and can affect thousands of hectares at once (ex. gypsy moth and spruce budworm). This also changes tree species composition as well as leaves dead wood behind as forest fire fuel

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12
Q

How do animals affect landscapes?

A
  • Beavers: when they abandon a dam, it breaks down and leaves nutrient-rich sediment behind (excrements) and allows succession to occur again
  • Blue jays: carry acorns over large distances and bury them, but won’t retrieve them all so some will be able to germinate. They are known as effective dispersers b/c carry “heavy seeds” farther, allowing range of oak trees to expand
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13
Q

How do humans influence forests?

A

Human activities intensely influence forests over short periods of time. Settlements create distinct patterns in forested areas.

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14
Q

What do cities do to forests?

A

They cause forest fragmentation b/c the majority of forest is lost, so they only exist in small and isolated patches. This is universal wherever humans have settled. :(

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15
Q

How does the impacts of forest management of timber harvesting vary?

A

The size of clear cuts and rotation lengths vary b/w countries, but cutting trees down in SA still affects in NA through climate change (C source).

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16
Q

How does patch size of clear cuts influence ecological processes?

A

It influences:

  • tree seed dispersal
  • wildlife dispersal
  • plant and animal habitat
  • amt of edge habitat
    ex. Small patches will have more edge than interior - circles are best b/c least amt of perimeter with max amt of interior.
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17
Q

What is a dispersed clear cut?

A

This is many small patches created due to clear cutting which causes high fragmentation :(

18
Q

What is a specific clear cut?

A

It specifically cuts trees to create a mosaic of continuous forest to allow for wildlife dispersal

19
Q

What are edge affects? How are edge effects reduced?

A
  • biomass loss
  • species distribution
  • tree mortality & growth
  • forest composition
    Small fragments have less interior, large fragments have high interior - fragment of ~50,000ha will have no edge effect
20
Q

What are the advantages of dispersal corridors?

A
  • wildlife dispersal
  • provides habitat
  • aids ecosystem processes (windbreak, riparian vegetation, protection of ecosystems)
21
Q

What are the disadvantages of dispersal corridors?

A
  • spread of disturbance (disease, exotic species/weeds, fire, makes hunting easier)
  • population sinks (causes reduced species survival and local species are often outcompeted)
  • financial cost vs. benefit (corridors re expensive to construct, so it may be more economical and place it under conservation status)
22
Q

Why is a landscape with high diversity (heterogeneity) better?

A

B/c it provides habitat for many different species. Fragmentation can cause certain species to only exist in one area, which can cause extinction

23
Q

How do red deer in the European Alps display interactions b/w landscape patterns and processes?

A
  • the red deer are traditionally found in valleys, but people settled there so the deer moved to higher elevations
  • the high deer density caused widespread damage to trees from eating buds and bark, meaning their ability to regenerate is reduced
  • this severely limits regeneration of alpine forests which is an issue b/c these forests important in protecting from avalanches
24
Q

How does fire suppression of Ponderosa pine forests in the USA display interactions b/w landscape patterns and processes?

A
  • fire has actively been suppressed in NA and is changing ecosystems where fire is natural
  • ponderosa pines are used to low burning fires, but the suppression has caused invasion of Douglas firs, which inhibits ponderosa regeneration
  • firs change the forest composition and is subject to spruce budworm outbreaks
  • when fire occurs, they are very intense infernos b/c lots of underbrush and dead biomass (limits ponderosas ability to survive)
25
Q

How do the terrestrial-aquatic interactions of CC pacific mountains and stream ecosystems display interactions b/w landscape patterns and processes?

A
  • the pacific NW mountains conifer forests have been clear cut
  • the steep slopes are prone to erosion (with potential for landslides), so forest streams receive high sediment load
  • the streams are also rising in temps due to lack of riparian forests and affects salmon fisheries
  • some recent legislation requires riparian buffer zone
26
Q

What is a watershed?

A

It is an area of land that drains water, sediment and dissolved materials to a common outlet at some point along the stream channel. They can be small (50ha) or very large (50,000ha)

27
Q

Why are watersheds so important?

A

They play central role in earth’s systems &water is essential for all life.
- is medium/pathway for biochemical processes/reactions
- redistributes energy via oceans and atmosphere
- contributes to erosion
- transports minerals & organics
(water is recycled through hydrological cycle)

28
Q

What is the pedosphere?

A

The outermost layer of the earth that is composed of soil. (part of hydrological cycle)

29
Q

What are the methods of water distribution?

A
  • precipitation
  • evaporation and transpiration
  • soil water
  • groundwater
  • runoff
  • streamflow
30
Q

How does precipitation distribute water?

A

It is the primary source of water for forest ecosystems, and there are regional differences in amount of precip received (related to climate).
- ex. high precip in equatorial zones due to trade winds on ocean and in pacific northwest due to rainshadow effect

31
Q

How does evaporation and transpiration distribute water?

A

Evaporation varies with vegetation type.

  • high vegetative cover means greater transpiration (from plants)
  • lower vegetative cover means greater evaporation
32
Q

What is rainfall interception?

A

It the amt of rainfall that is intercepted by trees in a forest. The type of forest will determine how much rain is intercepted and therefore how much water will end up in the soil.
- ex. conifers intercept 28% while deciduous intercepts 13%

33
Q

How does soil water influence distribution?

A

The amt of water soil can hold depends on the type of soil and vegetation as well as amt of vegetation.

  • ex. saturated soils are in peatlands while arid soils are in deserts
  • ex 2. clay infiltrates water slowly and drains slowly while sandy soil infiltrates and drains quickly (in b/w is best)
34
Q

How is water availability measured?

A

It is the difference b/w field capacity (max. when soil cannot drain) and wilting point (plant closes stomata and may be damaged)

35
Q

How does groundwater influence distribution?

A

It makes up 30% of the world’s total fresh water and is an important source of water for domestic consumption, irrigation and industrial processes.

36
Q

What is groundwater?

A

It is water that fills pore spaces of permeable materials, makes up ground water aquifers and is water stored below the water table

37
Q

What are lakes and streams?

A

All they are are bodies of water where the groundwater comes to the surface

38
Q

How does runoff influence distribution?

A

It varies with soil type because the soil can only absorb so much water, so the runoff is the water that can’t be absorbed. If there is high vegetative cover, then there is lower amts of runoff (forest vs cornfield vs bare field)

39
Q

How does streamflow influence distribution?

A

The streamflow (amt of water in streams) depends on:

  • the amt and intensity of precipitation
  • the annual cycles of precipitation (rainy vs dry season & spring/fall vs winter/summer)
  • spring snow melt (increases amt of water in streams)
  • dams (regulation of water flow by humans can influence streamflow)
40
Q

How have human activities altered watersheds?

A
  • land use change: deforestation changes stream flow
  • removal of riparian forests: compromises water quality and wildlife habitat
    Important to consider these effects in watershed management
41
Q

What would ecologically sound watershed/forest management consist of?

A
  • minimizing area of clearcuts
  • eliminating clear cut and replacing with selective cut
  • leaving riparian buffer strips