Transcript APES – Chapter 12 Species Biodiversity

Chapter 12
Sustaining Biodiversity:
The Species Approach
Key Concepts
 Human
effects on biodiversity
 Importance of biodiversity
 How human activities affect wildlife
 Management of wildlife
1%
Probably extinct
7%
Critically
imperiled
67%
Secure or
apparently
secure
8%
Imperiled
16%
Vulnerable
1%
Other
US Diversity
What Increases Biodiversity?
 Physically
diverse habitat
 Moderate environmental
disturbance
 Small variations in conditions
 Middle stages of ecological
succession
What Decreases Biodiversity?
 Environmental
stress
 Large environmental disturbance
 Extreme environmental conditions
 Severe limiting factors
 Introduction of alien (exotic) species
 Geographic isolation
Arctic Circle
60°
EUROPE
NORTH
AMERICA
30°N
Tropic of Cancer
Pacific
Ocean
0°
150°
120°
90°
Tropic of Capricorn
ASIA
Atlantic
Ocean
AFRICA
30°W
SOUTH
AMERICA
0°
Pacific
Ocean
60°E
90°
150°
Indian
AUSTRALIA
Ocean
30°S
Antarctic Circle
60°
ANTARCTICA
Critical and endangered
Threatened
Projected Status of Biodiversity
1998–2018
Stable or intact
Strategies for Protecting Species
Species Extinction
Local Extinction: when a species is no
longer found in the area that it once
inhabited (but is still found elsewhere in
the world)
 Ecological Extinction: so few members of a
species are left that it can’t play its
ecological role
 Biological Extinction: species is not found
anywhere on earth (permanent)

Endangered and Threatened
Species
Endangered Species: so few survivors that
the species could soon become extinct
 Threatened Species: still abundant in its
natural range but is likely to become
endangered due to declining numbers

Extinction Risks
Low reproductive rate (K-strategists): blue
whale, giant panda
 Specialized niche: giant panda
 Narrow distribution: island species
 Feeds at high trophic level: Bengal tiger,
bald eagle
 Rare: island species, orchids
 Commercially valuable: elephant

How Do We Estimate Extinction
Risks?
Population viability analysis (PVA): risk
assessment to predict whether a
population will persist for a certain # of
generations
 PVA is based on: resource needs, current
and predicted habitat conditions, genetic
variability, interactions with other species,
reproductive rates

Continued…

Minimum viable population (MVP):
smallest number of individuals necessary
for the survival of a population in a region

Minimum dynamic area (MDA): the
minimum area of habitat needed to
maintain the MVP
Why Should We Care About
Biodiversity?
Humans value nature in different ways
 Instrumental value: usefulness to us
 Intrinsic value: because they exist,
regardless of use
 Utilitarian (use): goods, services,
recreation
 Nonutilitarian (nonuse): aesthetic

Value of Nature
Instrumental
(human centered)
Utilitarian
Goods
Ecological services
Information
Recreation
Intrinsic
(species or
ecosystem
centered)
Nonutilitarian
Existence
Aesthetic
Causes of Depletion of Wild Species
 Human
population growth
 Failure to value the environment
 Increasing resource use
 Poverty
Habitat
loss
Habitat
degradation
Overfishing
Basic Causes
Climate
change
• Population growth
• Rising resource use
• No environmental
accounting
• Poverty
Introducing
nonnative
species
Commercial
hunting
Pollution
Predator
and
pest
control
Sale of
exotic pets
and
decorative
plants
Type of Nonnative Organism
Crop disease
Annual Losses and Damages
$23.5 billion
Crop weeds
$23.4 billion
Rats
$19 billion
Feral cats and outdoor pet cats
$17 billion
Crop insects
Livestock diseases
Forest insects and diseases
$14 billion
$9 billion
$4.8 billion
Zebra mussels
$3 billion
Common pigeon
$1.1 billion
Formosan termite
$1.1 billion
Fishes
$1.1 billion
Asian clam
$1.1 billion
Feral pigs
$0.8 billion
Starlings
$0.8 billion
Fire ant
$0.6 billion
Damage
from
Nonnative
Species
Characteristics of
Successful
Invader Species
Characteristics of
Ecosystems Vulnerable
to Invader Species
• High reproductive rate,
short generation time
(r-selected species)
• Similar climate to habitat
of invader
• Pioneer species
• Absence of predators on
invading species
• Long lived
• High dispersal rate
• Release growthinhibiting chemicals
into soil
• Generalists
• High genetic variability
• Early successional
species
• Low diversity of native
species
• Absence of fire
• Disturbed by human
activities
What Can Be Done to Reduce
Threat from Nonnative Species?
Identify characteristics that make species
successful invaders and use this
information to screen out invaders
 Increase inspections of goods coming into
a country
 Pass laws to ban the transfer of harmful
invader species

Biome
% of Area Disturbed
Temperate broadleaf forests
94%
Temperate evergreen forests
94%
Temperate grasslands
72%
Mixed mountain systems
71%
Tropical dry forests
70%
Subtropical and temperate
rain forests
67%
Cold deserts and semideserts
55%
Mixed island systems
53%
Warm deserts and
semideserts
44%
Tropical humid forests
37%
Tropical grasslands
26%
Temperate boreal forests
Tundra
18%
0.7%
Habitat
Disturbance
by Biome
Hunting and Poaching
Wild African Elephant
1970: 2.5 million
 Today: 300,000
 Killed for tusks (worth about $500-1500)
 Bleed to death
 1989 ban on sale of ivory from elephants
 Caused increased killing of walruses and
hippos for ivory

DO NOT POST TO INTERNET
Protecting Wild Species I
Bioinformatics: managing, analyzing, and
communicating biological information
 Involves: 1. building computer databases
2. developing computer tools to analyze
the information 3. communicating the
information
 Example: Species 2000- global research
project with the goal of providing
information about all species on earth

Protecting Wild Species II

International Treaties

Convention on International Trade in
Endangered Species (CITES) 1972
Signed by 152 countries
 Lists 900 species that cannot be
commercially traded
 Restricts international trade of 29,000
other at-risk species

Protecting Wild Species III

National Laws

Lacey Act of 1900: prohibits transportation
of live or dead animals (or their parts)
across state borders without a permit
 Endangered Species Act of 1973: illegal
for Americans to import or trade any
product made from an endangered or
threatened species
Protecting Wild Species IV
Habitat Conservation Plans
 Compromise between endangered species
and private landowners
 Landowners are allowed to kill a certain # of
endangered species on private land in
exchange for taking steps to protect the
species
Possible steps: setting aside a preserve for the
species, paying to relocate the species,
paying for government buy habitat elsewhere

Other Approaches to Protecting
Wild Species
 Wildlife
refuges and protected
areas
 Gene banks (storing plant seeds),
botanical gardens (cultivation of
rare and endangered plants), and
farms (raise for commercial sale)
 Zoos and aquariums
Wildlife Management
 Laws
regulating hunting and
fishing
 Harvest quotas
 Population management plans
 Improving habitat
 Laws for migrating species