22 terms

APES CHAPTER 12 - Sustaining Biodiversity The Species Approach


Terms in this set (...)

Case Study: Passenger Pigeon
The Passenger Pigeon used to be so abundant that it would darken the sky in its numbers in the 1800s, but by the 1900s the bird had disappeared.
Humans wiped them out from uncontrolled hunting, habitat loss through food supply and expansion
3 Types of Extinction
Local: a species is no longer found in an area it once inhabited but still found in other habitats
Ecological: few members of a species are left, can no longer fill its niche in its community
Biological: gone forever in all parts of the world
Endangered Species
A species that has so few survivors that it will most likely become extinct (panda bear)
Threatened Species
A species that is still abundant but numbers are lowering and it will most likely become endangered (polar bear)
Vulnerable Species
Another name for threatened species - still abundant but declining
Measuring Extinction Rates
Hard to figure out which species are becoming extinct
Can: study past records, observe number of species present and see if it increases with the size of an area
Extinction Characteristics (8)
Low Reproduction: lots of energy put into reproduction, very few offspring (blue whale, giant panda

Specialized: organism requires specific conditions to survive (blue whale, giant panda)

Distribution: limited habitat (elephant seal)

High Trophic Level: top predators are impacted when territory or food is impacted (grey wolf)

Fixed Migration: rely on specific sites for migration, if impacted possibility of no food or shelter (turtle)

Rare: not very many (orchid)

Commercial Value: fur, meat, oil, etc. is wanted by humans, have a high value in the market (snow leopard, white rhino)

Large Range: have a large range which makes it easier for them to be impacted by humans (grizzly bear, panther)
Human Impacts on Extinction
The increasing framentation and disturbances of habitats by humans are increasing throughout the world.
The real threat is long-term erosion in the earth's variety of species and habitats
Human activites have increased the rate of species extinction
Types of Instrumental Value (3)
Instrumental Value: based on their usefullness to us in form of economic and ecologial services (food, crops, lumber)
Genetic Information - use to make new types of crops, foods, medicine
Recreational Pleasure - spend many hours watching wildlife
Eco-tourism - generates $500 billion made each year, should not cause ecological damage, provide income, encourage support for wildlife
Case Study: Bats
Bats have two traits that make them vulnerable to extinction: reproduce slowly, live in huge colonies in caves and mines which people block.
Play important ecological roles: pollinate flowers, distribute plants, eat insects
They are a keystone species - vital for plant biodiversity and regenerating large areas of tropical forest
Several species have been driven to extinction
H - Habitat Destruction: human alteration to habitats (mining, agriculture)
I - Invasive Species: humans displace species (brown tree snake during WW1, killed 20 species)
P - Population Growth: increase in population of humans, habitat destroyed to increase room for living
P - Pollution: kill the habitat and species over time(oil spills, gas, plastics)
O - Overharvesting: humans are harvesting wild plants and animals at very high rates (hunting and fishing)

Habitat destruction is the greatest threat to biodiversity
Habitat Fragmentation
Occurs when large, continuous area of habitat is reduced in area and divided into smaller, scattered patches.
Divides populations
Species are more vulnerable to predators, invasion, disease, events
Creates barriers that can hinder some species from colonizing areas, getting enough food, mating
Species that are vulnerable to extinction because of it: rare, need large areas, cannot rebuild population, specialized
Case Study: Birds
One out of every 6 bird species is threatened with exinction - b/c of habitat loss and fragmentation
Nonative species like cats, rats, and snakes are the 2nd greatest threat
3rd greatest threat - being caught for pets and habitat loss
23 species of seabirds face extinction becasue of baited lines
Many kiled by skyscrapers, powerlines, towers, windows, oil spills, pesticides, lead shotgun pellets
Conservation biologists see this as an early warning of the greater loss of bioiversity to come
Birds play large ecological roles - control rodent populations, pollinate, excrete seeds
Non-native Species
Humans depend on nonnative organisms for services, food, shelter, medicine, and enjoyment
Not all nonnative species are horrible, some help the ecosystem, most are bad though
50,000 introduced into the US have caused ecological and economic harm
One of the biggest causes of animal and plant extinctions, threaten more than half of them
Deliberately introduced species have also caused damage
Case Study: Kudzu
Kudzu vine was imported from Japan in the 1930s and planted in southeastern US to help control soil erosion
Helped solve the erosion problem but engulfed hillsides, trees, houses, stream banks, forests
Spread throughout most of the south
It could eventually help save trees from loggers and could be used as a source of tree-free paper
Professional poachers get paid thousands of dollars to kill animals, many of which are threatened
Many poachers are not caught
Because of habitat loss and poaching there are now only 7,500 tigers in the wild compared to the 100,000 in the 1950s
Many animals are commercially valuable on the black market which makes them more suseptable to extinction
Case Study: Bushmeat
Indigenous people in west and central Africa have hunted bushmeat for centuries
Every type of wild animal is hunted for food or to supply restaurants
Bushmeat trade is increasing in many parts of the word
Has become widespread for four reasons:
1. an increase in Africa's population has caused more people to survive by hunting
2. more people are living in places that were once forests
3. restaurants have begun serving bushmeat
4. many people in poverty find selling wild animals is a way to get enough money
The problem: has caused ecological impacts, local extinctions of many species of animals and one species (red colobus monkey) to complete extinction, has reduced animal populations severely, threatens other animals food sources
Convention on International Trade in Endangered Species: 900 species cannot be commercially traded
Endangered Species Act
(ESA): Identifies and legally protects endangered species in the U.S and abroad. Most far reaching envi. law
Sanctuary Approach
President Roosevelt established the first US federal wildlife refuge in 1903, today there are 542 refuges
About 1/5 of US endangered and threatened species have habitats in the refuge system
Help many species recover
Conservation biologists want more refuges set aside to help endangered species
BAD: activities considered harmful to wildlife occur in nearly 60% of all wildlife refuges, nonnative species are invading the refuges, there is also too much hunting and fishing in the refuges
Gene Banks
They preserve the genetic information and plant species by storing their seeds in refrigerated, low-humidity environments
More than 100 world seed banks
Starting to store a more wide variety of plant species
BAD: expensive to operate, can be destroyed by accidents, stored seeds do not evolve, little funding, not enough room
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Reconciliation Ecology
Created by Michael L. Rosenzweig
The science of inventing, establishing, and maintaining new habitats to conserve species diversity in places where people play, live, and work.
Share space with other species