Download species - Bennatti

- Includes:
ecosystem diversity, species
diversity, and genetic diversity
1. Diversity of genes
Chihuahuas, Greyhound and Newfies are all dogs—
but they're not the same because their genes are
different.
Chihuahua
Greyhound
Newfoundland
Diversity of species
Hoary Bat
Iwi
Kahuli
Diversity of ecosystems
Desert
Tropical Rain Forest
tiaga
Biodiversity has Intrinsic Value
(value in and
of itself)
Source: Burmbaugh © AMNH-CBC
.
Biodiversity also has Utilitarian
Value
Utilitarian values include:
• Goods
• Services
• Information
What do we get from
biodiversity?
•
•
•
•
•
•
Oxygen
Food
Clean Water
Medicines
Beauty
Ideas/Inspiration
Biodiversity hotspots - areas with a high
concentration of endemic species,
experiencing rapid habitat loss
• Threatened (vulnerable) species:
– Still abundant in its natural range but is likely
to become endangered in the near future.
• Endangered species:
– So few individual survivors that it could soon
become extinct.
Current State of Biodiversity
• 1.4 million described species….perhaps
10 million in total???
• Background extinction rate (rate of
extinction in the absence of human
activities):
– In one year, a species has a one in ten
million chance of going extinct
• Mass extinction – loss of large number
of species
– usually due to catastrophic volcanic
eruption or meteor impact
– very rare (5 times in 3 billion years)
• Current rate of extinction???
Should we be concerned about
biodiversity?
What we know:
The Earth is losing species at an
alarming rate
• Perhaps as many as 3 species per hour
are going extinct and 20,000 extinctions
occur each year.
• when species of plants and animals go
extinct, many other species are
affected.
Core Case Study:
The Passenger Pigeon: Gone Forever
• Once the most
numerous bird on earth.
• In 1858, Passenger
Pigeon hunting became
a big business.
• By 1900 they became
extinct from overharvest and habitat
loss.
Passenger Pigeon: Hunted to
extinction
Former population about 6
billion animals
Carolina Parakeet: extinct
Habitat loss (forest clearing), over hunted (for feathers
and by farmers who considered them a pest)
Ivory-Billed Woodpecker: Critically
endangered, probably extinct
Once found in southern
hardwood swamps and
pine forests
Comparison of ivorybilled (top) and pileated
woodpecker below)
Threats to Species: Remember
H.I.P.P.C.O.
• H.I.P.P.C.O. – the most important causes
of extinction:
– Habitat destruction, degradation, and
fragmentation
– Invasive (nonnative) species
– Population and resource use growth
– Pollution
– Climate change
– Overexploitation
Extinctions Can Be Natural But
Sometimes The Rate Increase Sharply
– Local Extinction (Extirpation):
• A species is no longer found in an area it once
inhabited but is still found elsewhere in the world.
• Typically the result of habitat destruction or
overhunting and affects more than one species.
– Examples: wolf and mountain lion in Maine
• Extinction (Global extinction) is Forever.
Characteristics of Species That Are Prone to Extinction
 These characteristics
make survival harder
when environmental
conditions change or
when humans interfere.
 Endemic Species
• Only live in one specific place (geographic
location or habitat type – usually islands)
• Very vulnerable to extinction as a result of
habitat loss or degradation.
Habitat destruction and
fragmentation
Fragmentation- breaking large areas of
habitat into smaller, isolated patches
Golden lion tamarin
Changes in housing density in Southern Maine
Source: http://www.whrc.org/mapping/somaine/housing.html
Edge Effects-negative impacts
adjacent to habitat boundaries
Forest Edges:
-more sunlight
-drying
-higher winds
-higher tree mortality
-more invasive species
-more predators
Edge area
Core area
• Core area – part of a patch not impacted by
edge effects
• Patch size is not always the best predictor of
patch quality
Introduced Species
Humans are constantly moving species to new
locations
Sometimes this is done deliberately, sometimes
by accident
Often the most serious impacts are on islands
due to:
-low species diversity
-few native predators so many species have
not developed anti-predator defenses (or
resistance to diseases)
https://www.youtube.com/watch?v=mUssO68D2eM
Characteristics of Invasive Species
-pioneer species
-high dispersion rates
-found in disturbed habitats…..but some
can invade undisturbed areas
Why are invasives successful?
-Often have no diseases, nothing that will
eat them, no parasites
-outcompete native species for resources
• Introduced diseases – exploit lack of
evolved resistance
– Dutch elm disease – American elm
– Chestnut blight – American chestnut
– avian malaria – Hawaiian birds
– Rinderpest – African ungulates
– chytrid fungus – amphibians
Net result of invasive species
• Homogenize ecological communities
around the world
• Drive native species to extinction
Exploitation and overharvest
• Direct exploitation for food
– Overfishing
– Bycatch
– Bushmeat = harvest of wild animals for
food
– Can be sustainable but is often not
– Threatens many species of primates and other
mammals as well as other wildlife
– Primarily a concern when it is obtained illegally,
commercially and/or unsustainably
Global Trade in Wildlife
• Birds, orchids, cactus, primates…
• Captured for gardens, pets, zoos….
• Many species were driven to extinction
before regulations were enacted to
protect them (Ex: passenger pigeon,
Carolina parakeet, sea mink…)
5. Climate change
Why do small populations go
extinct?
• chance events that occur more
frequently with small populations size
– failure to breed or survive
– failure to find a mate
– skewed sex ratio
• Environmental effects – unpredictable
events that reduce survival or
reproduction
– droughts, floods, fires, storms
• Genetic effects at small population size
– inbreeding
– genetic drift
– random mutations
• Extinction vortex – combination of
genetic, environmental and
demographic factors that drive a small
population to extinction
Heath Hen
Heath hen
• 1700 – throughout the northeast coast
• 1907 – 50 left on Martha’s Vineyard
• 1915 – 2000 birds
• 1916 – fire
• 1917 – goshawk invasion
• 1920’s – poultry disease
• 1927 – 13 birds, mostly males
• March 11, 1932 – last known sighting
Greater Prairie Chicken
Conservation Status:
Vulnerable
Populations that are very small suffer from lack of
genetic diversity (for example cheetahs)
3. Maintenance of ecosystem function
• How many species can you safely
remove?
• How do you ensure maximum
productivity in managed or natural
ecosystems?
More diverse ecosystems are more stable
http://image.slidesharecdn.com/06piajonssoncitespresentationsiameserosewood-141218174854-conversiongate02/95/06-pia-jonsson-cites-presentation-siamese-rosewood-7-638.jpg?cb=1418925212