Chap 21 Landscape Ecology

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Chap 21 Landscape Ecology

• ???(Ayo)
• ???? ???? ??

Ayo ??? http//mail.nutn.edu.tw/hycheng/ Email
add Japalura_at_hotmail.com
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Fig. 21.1 The view from hills and mountains, such
as this one, were used traditionally in ancient
Japan to survey the surrounding lands.
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Introduction

• 13??,????Jomei ?????????Mount Kagu(Nara
  prefecture)????????
• ?????,?????????????????,??????(kunimi)
• ???????,?? religious(???), esthetic(???),
  economic(???), and political(???) reasons.

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Landscape ecology

• Is young as a scientific discipline.
• The emergence of landscape ecology coincides with
  the widespread availability of aerial photos
  (Fig. 21.2) and satellite images (Fig. 21.3).
• Landscape ecologists study landscape structure,
  processes, and change.

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Concepts

• Landscape structure includes the size(??),
  shape(??), composition(??), number(??), and
  position(??) of different ecosystems within a
  landscape (??).
• Landscape structure influences processes such as
  the flow of energy, materials, and species
  between the ecosystems within a landscape.
• Landscapes are structured and change in response
  to geological process, climate, activities of
  organisms, and fire.

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Concept discussion 1

• Landscape structure includes the size(??),
  shape(??), composition(??), number(??), and
  position(??) of different ecosystems within a
  landscape (??).
• The structure of six landscapes in Ohio
• The fractal geometry(???????) of landscapes

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The structure of six landscapes in Ohio

• In 1981, Bowen and Burgess published a
  quantitative analysis of several Ohio landscapes.
  (Fig. 21.4)
• Quantified patch shape by ratio of patch
  perimeter to perimeter of a circle with an area
  equal to that of the patch.
• S P(2v?A)
• S Patch shape(??)
• Increasing value indicates less circular shape
• P Patch perimeter (??)
• A Patch area (??)
• Fig. 21.5(p.514) ? Fig. 21.6(p.515)

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Landscape Structure
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The Fractal Geometry of Landscapes

• Fractal geometry was developed by Benoit
  Mandelbrot (1982).
• Bald eagles (??) vs. barnacles (??)
• ??? 0.782KM vs. ????2cm(0.00002KM)
• The perimeter of the island is 760KM (eagles
  ruler)
• The perimeter is 11,00KM (tiny ruler).

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Fractal Geometry of Landscapes
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Concept Discussion 2Landscape processes

• ??????????(??),??
• the flow of energy, materials, and species
  between the ecosystems within a landscape.
• the dispersal of organisms, local population
  density, extinction of local populations, and the
  chemical composition of lakes.
• The dispersal of small mammals (p.517)
• The density of butterfly population (p.518)
• Habitat corridors (??) (p.519)
• Lake chemistry (????) (p.520)

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Landscape Structure and Dispersal of Small Mammals

• Ecologists have proposed landscape structure can
  influence movement of organisms between
  potentially suitable habitats.
• Metapopulations Populations of many species
  occur in spatially isolated patches, with
  significant exchange of individuals.
• Rate of movement of individuals between
  subpopulations can affect species persistence in
  a landscape.

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Landscape Structure and Dispersal of Small Mammals
Fig. 21.11 Influence of patch size on small
mammal movements
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Landscape Structure and Dispersal of Small Mammals

• Diffendorfer et. al. studied how patch size
  affects movement of three small mammal species.
• Predicted animals would move farther in more
  fragmented landscapes.
• Must move farther to obtain resources.
• Predicted animals would stay longer in more
  isolated patches.

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Density of Butterfly Populations

• Hanski et. al. (1994) found butterfly density
  significantly affected by size and isolation of
  habitat patches.
• Population size within patch increased with patch
  area.
• Population density decreased as patch area
  increased.
• Isolated patches had lower butterfly densities.
• Population partially maintained by immigration.

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Habitat Patch Size and Isolation and Density of
Butterfly Populations
Fig. 21.13 Relationship between habitat patch
area and population size and density of the
butterfly in a landscape.
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Habitat Corridors (????)

• Connecting habitat fragments with corridors of a
  similar habitat has long been an approach to
  mitigating the effects of habitat
  fragmentation.(????????)
• Haddad and Baum (1999) found corridors influenced
  the movement of butterflies associated with early
  successional habitats.

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Landscape Position and Lake Chemistry

• Webster (1996) explored how lake position in a
  landscape affected chemical responses to drought.
• Lake position in landscape determined portion of
  water received as groundwater.
• Fig. 21.15 Lake position in the landscape and
  proportion of water received as groundwater.
  (p.522)

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Landscape Position and Lake Chemistry
Fig. 21.15 Lake position in the landscape and
proportion of water received as groundwater.
(p.522)
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Concept discussion 3

• Landscapes are structured and change in response
  to geological process, climate, activities of
  organisms, and fire.

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Soil and Vegetation Mosaics In Sonoran Desert

• McAuliffe (1994) showed bajadas in Sonoran
  Desert are complex mosaic of distinctive
  landforms.
• Found wide range of soil types and plant
  distributions that correspond closely to soil age
  and structure.
• Soil structure influences perennial plant
  distributions.
• Plant distributions map clearly onto soils of
  different ages.

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Soil and Vegetation Mosaics In Sonoran Desert
Fig. 21.19
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Climate and Landscape Structure

• McAuliffe (1994) Soil mosaics consisted of
  patches of material deposited during floods
  originating in nearby mountains.
• Materials eroded from mountain slopes and
  deposited as alluvium (???) on surrounding
  bajadas.
• Alluvial deposits gradually changed dependent
  upon climate.
• Different soils and plant types.
• Fig. 21.20 Association between vegetation and
  soils of different ages and structure on the
  Tucson Mountains bajada.

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Organisms and Landscape Structure

• Many studies have focused on conversion of forest
  to agricultural landscapes.
• Eastern NA, many abandoned farms have reverted to
  forest, thus forest cover has increased.
• Similar patterns in parts of Europe.

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Organisms and Landscape Structure

• Hulshoff (1995) found forest and heathland (???)
  coverage changed over time as well as number
  and average area of patches.
• Cadiz Township - agricultural economy converted
  area from forest to farmland.
• Economy collapsed in response to introduction of
  synthetic fertilizers and inexpensive imported
  wool.

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Organisms and Landscape Structure
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Organisms and Landscape Structure

• African elephants knock down tress.
• Change woodland to grassland.
• Kangaroo Rats dig burrow systems that modify soil
  structure and plant distributions.
• Beavers cut trees, build dams and flood
  surrounding landscape.
• At one time, beavers modified nearly all
  temperate stream valleys in Northern Hemisphere.

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Organisms and Landscape Structure

• Johnston and Naiman documented substantial
  effects of beavers on landscape structure.
• Over 63 yrs, area created by beavers increased
  from 200 ha to 2,661 ha.
• Changed boreal forest landscape to complex mosaic.

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Organisms and Landscape Structure

• Beaver activity between 1927-1988 increased
  quantity of most major ions and nutrients in
  impounded areas. Three possible explanations
• Impounded areas may trap materials.
• Rising waters captured nutrients formally held in
  vegetation.
• Habitats created by beavers may promote nutrient
  retention by altering biogeochemical processes.

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Fire and Structure of a Mediterranean Landscape

• Minnich used satellite photos to reconstruct fire
  history of S. CA and N. Baja (1971-80).
• Landscape consisted of patchwork of old and new
  burns.
• Similar climates with deviated fire histories
• Fire suppression in S. CA allowed more biomass
  accumulation and resultant large fires.
• Small burns more frequent in N. Baja.
• Other factors

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Applications Tools

• Riverine Restoration The Kissimmee River
• The restoration project will take about 15 years
  and restore about 70km of river channels to a
  more natural condition and about 11,000 ha of
  wetlands.
• The projected costs of repairing the damage to
  the Kissimmee landscape is 500 million.
• The first phase of the restoration was completed
  in 2001.

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