Pigeon Key Marine Science Center

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Pigeon Key Marine Science Center
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(http//www.conbio.org/Jobs/detail.cfm?id14507)
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Fergus Gill Young Photographer
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Igor Shpilenok Urban Garden Wildlife
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Jose Luis Rodriguez Veolia Award 2009
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Invasive Species(cont)
27 Oct 2009
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Characteristics of Successful Invasives

• Capable of saturating new environments with
  propagules.
• high reproductive rate/potential
• invasion attempts are repetitive
• Capable of persisting at low densities, possibly
  under adverse conditions, for extended periods.
• Ecologically compatible with new environments
  (ecological match).
• able to out-compete, kill, or consume native
  species

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Which exotics are most likely to become
successful invasives?
(Rejmánek Richardson. 1996. Ecology)
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Which exotics are most likely to become
successful invasives?
- unsuccessful colonists
- successful colonists
Percent of species
(Veltman et al. 1996. American Naturalist)
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Fast and flexible

• Quick to abandon hives.
• Fast moving swarms.
• Can build hives anywhere.

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One tough customer

• Competes with or kills European honeybees.
• Aggression promoted by native predators.

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Characteristics of Successful Invasives

• Capable of saturating new environments with
  propagules.
• high reproductive rate/potential
• invasion attempts are repetitive
• Capable of persisting at low densities, possibly
  under adverse conditions, for extended periods.
• Ecologically compatible with new environments
  (ecological match).
• able to out-compete, kill, or consume native
  species

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Managing Invasives

• Prevent entry of exotic species
• Which are the most compatible with local
  environmental conditions?
• Which are the most mobile?
• Where are the most likely points methods of
  entry into the local community?
• Invasive richness and abundance are usually
  greatest near large transport centers (e.g. ship
  yards).

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Managing Invasives

• Address invasions immediately
• Small exotic populations can often be eradicated,
  but are difficult to detect.
• Isolate exotics with migration barriers.
• Eradication methods include
• active culling (e.g. hunting)
• physical excavation (plants)
• chemical controls (plants insects)
• biological controls

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Biocontrol
Aquatic weevil vs. Nuisance aquatic vegetation
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Managing Invasives

• Mitigate invasive effects
• Once invasives become established, eradication
  may no longer be feasible.
• Employ ecological management strategies that
  confer advantages to native species.
• selective harvest
• controlled environmental regimes
• continued biological control

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Biocontrol
Goats vs. Kudzu
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Biocontrol
Goats vs. Kudzu
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Biocontrol
Goats vs. Kudzu
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Biocontrol
Phorid fly vs. Red fire ant
(click)
(Orr et al. 1995. Nature)
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Managing Invasives
http//www.invasivespecies.gov/
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Biological Reserves I
27 Oct 2009
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Basic Rules for Reserve Design- Island
Biogeography -
IMMIGRATION
EXTINCTION
close islands
small islands
Rate ?
distant islands
large islands
Number of Species ?
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Effects of Distance Island Size
IMMIGRATION
EXTINCTION
close islands
small islands
Rate ?
mainland
distant islands
large islands
Number of Species ?
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Effects of Distance Island Size
IMMIGRATION
EXTINCTION
close islands
small islands
Rate ?
mainland
distant islands
large islands
Number of Species ?
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Effects of Distance Island Size
IMMIGRATION
EXTINCTION
close islands
small islands
Rate ?
mainland
distant islands
large islands
Number of Species ?
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How large do reserves need to be?
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How large do reserves need to be?
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How large do reserves need to be?

• Minimum viable population standards
• Identify species of greatest concern.
• threatened/endangered
• charismatic megafauna
• indicators
• keystone
• Use PVA to determine MVP sizes.
• Divide MVP size by population density (no.
  individuals per unit area) to estimate minimum
  reserve size.

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How large do reserves need to be?- Grizzly Bear
Example -

• MVP Analysis
• Objective 95 probability of survival for 100
  yrs.
• MVP size 75 breeding adults (Ne).
• Accounting for variation in mortality rate,
  females, litter size, age at first reproduction,
  and cub sex ratio.
• Field density 1 adult / 135 km2.
• Therefore, reserve size must be 10,125
  km2 (2.5 million acres).
• Yellowstone Park 9000 km2.

(Shaffer Samson 1985)
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Single Large or Several Small? (S.L.O.S.S.)
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Edge Effects
total interior habitat 64 ha total edge habitat
36 ha
total interior habitat 36 ha total edge habitat
64 ha
(1 hectare 2.5 acres)
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Edge vs. Interior Ratios
10 km2
10 km2
10 km2
perimeter 19.0 km
perimeter 11.2 km
perimeter 12.6 km
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(Laurance et al. 2002)
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Edge Effects - Physical Characteristics -

• Higher solar insolation.
• warmer less humid than interior habitats
• radiation moisture flux higher
• evening frosts more frequent/extensive
• Higher wind turbulence shear.
• edges more vulnerable to wind damage
• increased evapotranspiration desiccation
• Modified hydrology.
• reduced interception (diminished tree canopy)
• greater runoff surface erosion

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Edge Effects - Biological Characteristics -

• Increased predation parasitism.
• predatory parasitic species capable of
  penetrating deeper into interior habitat
• Increased herbivory.
• edge species gain greater access to interior
  growth

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Brown-headed Cowbird

• parasitize gt150 species
• parasitism rates up to 90
• search for hosts at woodland edges
• rely on non-woodland food sources
• rare in large forest tracts

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Brown-headed Cowbird
Nests parasitized
Daily nest mortality
(Robinson et al. 1995)
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Fragmentation Human Health
Borrelia burgdorferi
blacklegged tick
Lyme Disease
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Fragmentation Human Health
(Allan et al. 2003)
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Fragmentation Human Health
(Ostfeld Keesing 2000)
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Fragmentation Reduces Small Mammal Diversity-
Dilution Effect -
blacklegged tick
meadow vole
masked shrew
white-footed mouse
fox squirrel
chipmunk
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Fragmentation Human Health
blacklegged tick
white-footed mouse
Borrelia burgdorferi
Lyme Disease
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Reading Assignments

• Read text p. 368-402.