Download Keystone species

Conservation of Biodiversity
• What causes biodiversity
decline?
• Describe methods for
monitoring & protecting
species
• Understand why
connectedness is important
in protecting species
• Identify services that species
offer to ecosystems
How many species are there?
• Estimates vary widely 3-10 million
• Latest scientist estimate is around 6.8 million
• Nearly 1/3 of all species are threatened
Categories of Endangerment




Extinct- no longer exist
Threatened- species with a high risk of
extinction in the future
Endangered- seriously at risk of extinction
Least concerned- no serious threat, abundant
Why are Amphibians more
threatened?
• Live in all of the
biosphere, land, water
& air
• Sensitive skin
• Eggs are clear so toxins
can easily enter
• Thin Green Line short
video
Extinctions
5 mass extinctions on Earth
• Two largest
• Permian Extinction 248
million YA
• Cretaceous Extinction
65 million YA
• 21% are threatened due
to reduced habitat,
rising sea levels
• Since 1500 133 bird
species are extinct. 1/3
of U.S. Pop. is declining
• Of 5,500 mammal
species since 1500 79
are extinct.
Causes of Extinction
•
•
•
•
•
•
Hunting
Food
Medicine
Poaching-illegal hunting
Export/import of non-native species
Destruction of habitat-deforestation
Habitat Loss


For most species the greatest cause of decline and
extinction is habitat loss.
50% of grasslands 30% of deserts from 1998-2004
wetlands increased. But not to the level of the 1600’s
Change in Forest Cover
Invasive/Introduces Species





Alien species (exotic species)- species that live
outside their historical range.
Invasive species- when alien species spread
rapidly across large areas.
Ex- Kudzu Vine, Zebra Mussel, Silver Carp,
Snakehead fish. Burmese python
Due to global trade, travel, illegal trade
Ship bilge water –plants, fish shellfish
Keystone species
Keystone Species
• A keystone species is a plant or animal that
plays a unique and crucial role in the way an
ecosystem functions.
• Without keystone species, the ecosystem
would be dramatically different or not exist.
• Let’s look at some examples
Pollution





Threats to biodiversity can come from toxic
contaminants
Pesticides
heavy metals
acid rain
oil spills.
Climate Change


Concern how climate change will affect
temperature and precipitation around the world,
and how this will impact biodiversity.
Sea level changes, plant growth, migration to
climates that are better suited
Overharvesting


When individuals of a species are removed at a rate
faster than the population can replace them.
American bison 60-75 million by late 1800’s less than
1,000, now 50,000.
Bison skulls
Dodo bird
Endangered Species Act



Endangered Species Act- first passed in 1973, it
authorizes the U.S. Fish and Wildlife Service to
list species as threatened or endangered &
prohibits harming these species.
Trading these species is also illegal.
also authorizes the government to purchase
habitat that is critical to the species.
Habitat Fragmentation




When designing and managing protected areas a number
of factors must be considered
how close to another area they should be, how large the
area is, the amount of edge habitat the area contains, &
connectedness
Edge habitat- the area where two different communities
come together, typically forming an transition.
Would there be more or less biodiversity in an edge
habitat?
Dilemma
• Due to limited resources should we try to save
a single large area or several small ones?
• A single large area supports many species
• A species though is more likely to survive a
disease or natural disaster if it occupies
several areas
• This dilemma is called Single Large or Several
Small- SLOSS
Fragmentation of Habitat
Biosphere Reserves
• When large areas are protected they may be used for
recreation, so they may be disturbed by humans
• 3 Zones to minimize human impact.
• 1. Central core should have minimal human impact. This is
the best area for biodiversity
• 2. Buffer zone surrounds the core. This is for modest
amounts of human impact-tourism, education & research
• 3. Transition area might include sustainable logging,
agriculture & residences for locals
Biosphere Reserves Big Bend

Protected
areas
consisting of
zones that
vary in the
amount of
permissible
human
impact.
Methods to Monitor Species
Populations
•
•
•
•
Tagging
GPS
Netting
Trapping
Remediation v Restoration
• Restoration "return of an ecosystem to a close
approximation of its condition prior to
disturbance.” from the EPA’s website
• Remediation removal of pollution or
contaminants from environmental such as soil,
groundwater, sediment, or surface water.
• Which might require more money and time?
• Let’s watch a video
Bioremediation
• Waste management technique that involves
the use of organisms to remove or neutralize
pollutants from a contaminated site.
According to the EPA, bioremediation is a
“treatment that uses naturally occurring
organisms to break down hazardous
substances into less toxic or non toxic
substances”.
• Examples Plants roots, Bacteria, fungi