Community Ecology

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Community Ecology

• Each species has a particular ecological niche or
  role that it plays in an ecosystem.

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r-Selected Species
Cockroach
Dandelion
Many small offspring Little or no parental care
and protection of offspring Early reproductive
age Most offspring die before reaching
reproductive age Small adults Adapted to
unstable climate and environmental
conditions High population growth rate
(r) Population size fluctuates wildly above and
below carrying capacity (K) Generalist
niche Low ability to compete Early successional
species
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Characteristics of Successful Invader Species
Characteristics of Ecosystems Vulnerable to
Invader Species

• High reproductive rate, short generation time
  (r-selected species)
• Pioneer species
• Long lived
• High dispersal rate
• Release growth- inhibiting chemicals into soil
• Generalists
• High genetic variability

• Similar climate to habitat of invader
• Absence of predators on invading species
• Early successional systems
• Low diversity of native species
• Absence of fire
• Disturbed by human activities

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Cockroaches Natures Ultimate Survivor

• Appeared in the geologic record 350 million years
  ago.
• Classic r-strategist generalist
• Eat almost anything including algae, dead
  insects, salts in tennis shoes, electrical cords,
  glue, paper, soap, and weaker cockroaches.
• Some species can go for months without food, last
  a month without water, withstand massive doses of
  radiation, one species can even survive being
  frozen for 48 hours.
• High reproductive rates (1 female can produce 10
  million offspring in one year)
• Carry viruses that cause hepatitis, polio,
  typhoid, and salmonella.
• 60 of the 12 million Americans suffer from
  asthma are allergic to cockroaches, dead or
  alive.

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K-Selected Species
Saguaro
Elephant
Fewer, larger offspring High parental care and
protection of offspring Later reproductive
age Most offspring survive to reproductive
age Larger adults Adapted to stable climate and
environmental conditions Lower population growth
rate (r) Population size fairly stable and
usually close to carrying capacity
(K) Specialist niche High ability to
compete Late successional species
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The Giant Panda Specialized and Endangered

• Classic k-strategist specialist
• Feeds exclusively on bamboo (1/3 of body weight)
• Habitat fragmentation has created habitat
  islands of bamboo in southwestern China due to
  human encroachment.
• 12 protected reserves in China.

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Why Are Panda Faced With Extinction?

• Illegal poaching (pelt brings in 40,000-60,000).
• Only one cub per female survives each year.
• Gestation period 22 months
• Picky about mates. Find each other through
  scent, become isolated due to habitat
  fragmentation.
• Habitat islands interrupt natural migration to
  adjacent areas when bamboo population crashes in
  local areas.
• Approximately 700 panda left between zoos and the
  wild.

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Panda Babies

• Five giant panda cubs were born in captivity in
  2005 one at Washington, D.C.'s National Zoo and
  two pairs of twins (one of which is pictured
  above) at China's Wolong panda reserve.
• US pays 1 million/year to China to have Mei Xiang
  on exhibit for a ten year period. All offspring
  will be sent back to China.

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What Are Indicator Species?

• Indicator species serve as early warnings of
  damage to a community.
• Birds and butterflies are migratory and are
  excellent indicators of the environment. They do
  not return to areas along their migratory routes
  where deforestation has occurred or where broad
  spectrum pesticides have been applied.
• Amphibians are also a universal indicator of
  environmental degradation as they respire through
  their skin.

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Why Are Amphibians Vanishing?

• Appeared in the fossil record about 350 million
  years ago.
• Frogs and toads have been around for 150 million
  years (indicates adaptability)
• Last 20 years nearly 3,000 species of frogs and
  toads have disappeared.

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Reasons for Global Amphibian Declines

• Global climate change (Costa Rican golden toads)
• Dehydration weakens amphibians, susceptible to
  fatal diseases.
• Introduction of non-native predatory fish into
  aquatic habitats.
• Pollution (air, water, soil) respire through
  skin.
• Consume insects that take up pesticides
  (bioacumulation/biomagnification).
• Eggs sensitive to increases in UV radiation
  endocrine blockers)
• Consumption of frog legs (delicacy).
• Loss of habitat.

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Indicator Species

• As indicator species, amphibians may be sending
  us an important message about the health of the
  global environment.
• They dont need us, but we and other species need
  them.

Golden toads once prevalent in Costa Ricas
cloud forest have disappeared.
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Indicator Species on Long Island
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Why Should We Care About Indicator Species?

• They give clues that the environmental health is
  deteriorating in parts of the world such as
  habitat loss and degradation, pollution, UV
  exposure, and climate change.
• They provide ecological services (niche) in
  biological communities. ie. Amphibians eat more
  insects including mosquitoes than birds. They
  provide a food source for higher trophic levels.
• Amphibians especially provide a storehouse of
  pharmaceutical products waiting to be discivered
  (economic goods and services).

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What Are Keystone Species?

• A keystone species holds a community together,
  when it disappears, so does the biological
  community. Elimination of a keystone species
  dramatically alters the structure and function of
  a community.

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American Alligator a Keystone Species

• Largest North American reptile only humans are
  their predator.
• Hunted nearly to extinction for exotic meat, and
  leather to make shoes and pocketbooks, and for
  sport.

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Ecological Niche of American Alligator

• Dig gator holes that collect freshwater during
  the dry season which serve as refuges for aquatic
  life, and supply freshwater and food for many
  animals.

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Ecological Niche of American Alligator

• Alligator nesting mounds serve as nesting and
  feeding sites for herons and egrets

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Ecological Niche of American Alligator

• Alligator eat large numbers of predatory gar fish
  and help maintain healthy numbers of game fish
  such as bass and bream.

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Ecological Niche of American Alligator

• As alligators move from gator holes to nesting
  sites, they keep areas of open water free of
  invading vegetation. This helps to maintain
  healthy ecosystems with flowing water.

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American Alligator Protection

• In 1967, the US Government placed the American
  alligator on the Endangered Species List, which
  protected it from hunting.
• By 1975, the American alligator populations
  rebounded successfully.

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Status of the American Alligator.

• In 1977, the US Fish and Wildlife Service (DOI),
  down-listed the American alligator to a
  threatened species in Florida, Louisiana, and
  Texas.
• Limited kills with a license are permitted.
  Recreational lotteries are held in the Florida
  Everglades each year by FWS.
• Alligator farms established to fulfill the market
  for alligator goods.

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Why Should We Protect keystone Species?

• They play critical roles in the cross pollination
  of angiosperms (bees, hummingbirds, bats).
• Top predator keystone species help regulate the
  population numbers of other species.
• The loss of keystone species can lead to
  population crashes and extinctions of other
  species that depend on it for ecological
  services.

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E.O. Wilson

• The loss of a keystone species is like a drill
  accidentally striking a power line. It causes
  lights to go out all over

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The Good News Is

• Conservation Efforts on the rise
• President Theodore Roosevelt (1901-1909) the
  Golden Age of Conservation
• 1903 he established the first federal refuge at
  Pelican Island off the east coast of Florida to
  protect the endangered brown pelican.

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Roosevelt

• T. Roosevelt also tripled the size of the forest
  reserves and transferred administration from
  Department of the Interior (USDOI) to Department
  of Agriculture (USDA.
• 1905, Congress created the US Forest Service to
  manage and protect forest reserves. Roosevelt
  appointed Gifford Pinchot as its first chief.
• 1907, Roosevelt reserved 16 million acres of
  land. Congress was trying to ban Executive
  orders for forest reservation. Roosevelt did
  this defiantly the day before Congress ban
  became law!

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Pinchot

• (1905) Pinchot pioneered scientific management of
  forest resources on public lands, using the
  principles of sustainable yield and multiple use.
• This same year, the Audubon Society was founded
  to preserve the nations bird species.

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Conservation Split

• Conservationists became the wise-use movement
  and believed that all public lands should be
  managed wisely and scientifically to provide
  needed goods and services for the country.
• Preservationists lead by John Muir (founder of
  Sierra Club) believed that remaining wilderness
  areas on public lands should be left untouched.

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Preservationists

• Aldo Leopold began the Wilderness Society in
  1935.
• Leopold helped draft the Wilderness Act of 1964
  and lobbied Congress for its passage.

University of Idaho Department of
Philosophy Environmental Philosophy
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Wilderness Act of 1964

• Wilderness Act of 1964 directed the Secretary of
  the Interior, within 10 years, to review every
  roadless area of 5,000 or more acres and every
  roadless island (regardless of size) within
  National Wildlife Refuge and National Park
  Systems and to recommend to the President the
  suitability of each such area or island for
  inclusion in the National Wilderness Preservation
  System, with final decisions made by Congress.
  The Secretary of Agriculture was directed to
  study and recommend suitable areas in the
  National Forest System.

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US National Park Service

• 1912, Congress created the US National Park
  Service.
• 1916, Congress passed the National park System
  Organic Act declared that the parks were to be
  maintained in a manner that leaves them
  unimpaired for future generations and established
  the National Park Service (DOI).
• Stephen Mather was the first Director of NPS. He
  began establishing grand hotels and other tourist
  facilities in parks with spectacular scenery to
  encourage tourism by allowing private
  concessionaires to operate facilities within the
  parks.

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Long Islands National Parks and National
Wildlife Refuges

• Fire Island National Seashore
• Floyd Bennett Field
• Jamaica Bay
• Wortheim
• Amagansett
• Oyster Bay (JFK Bird Sanctuary)
• Lido Beach
• Elizabeth Morton
• Target Rock (Caumsett State Park)
• Seatuck
• Conscience Point

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Aldo Leopold

• We abuse land because we regard it as a
  commodity belonging to us. When we see land as a
  community to which we belong, we may begin to use
  it with love and respect