Area VII: Global Change VIIC: Loss of Biodiversity

Area VII: Global Change

VIIC: Loss of Biodiversity

11-1 Human impacts on terrestrial biodiversity

Humans have degraded much of the Earth most temperate and tropical ecosystems

(except deserts) have been disturbed by humans

in U.S. 95% of virgin forests have been cut, and 98% of tallgrass prairie has disappeared

biodiversity has intrinsic (existence) and extrinsic (instrumental, use) value

Biodiversity

Increase Factors

•Middle stages of succession

•Moderate environmental disturbance

•Small changes in environmental conditions

•Physically diverse habitat

•Evolution

Decrease Factors

•Extreme environmental conditions

•Large environmental disturbance

•Intense environmental stress

•Severe shortages of key resources

•Nonnative species introduction

•Geographic isolation

Fig. 11-2 Factors affecting biodiversity

Human PopulationSize and resource use

Human ActivitiesAgriculture, industry, economic

production and consumption, recreation

Indirect Effects

Direct EffectsDegradation and destruction of natural ecosystems

Alteration of natural chemicalcycles and energy flows

Changes in number and distribution of species

Pollution of air, water, and soil

Climate change

Loss of biodiversity

Fig. 11-3 Human affects on biodiversity

Projected Status of Biodiversity1998–2018

Critical and endangered Threatened Stable or intact

ANTARCTICA

NORTHAMERICA

EUROPE

AFRICA

ASIA

SOUTHAMERICA AUSTRALIA

PacificOcean

Antarctic Circle

PacificOcean

Tropic of Cancer

Tropic of CapricornIndianOcean

AtlanticOcean

150°90°60°E0°30°W90°120°150°0°

60°

30°N

30°S

60°

Arctic CircleArctic Circle

Fig. 11-4 Future of biodiversity

13-2 Human impacts on aquatic biodiversity

Humans threats to aquatic biodiversity ~75% of the commercially valuable marine

fish species are either overfished or fished to their sustainable limits

overfishing leads to commercial extinction big fish of commercially valuable species are

becoming scarce during the last 45 years, the abundance of

large, open-ocean dwelling fish has plummeted by 90%


overfishing, cont. 230 populations of marine fish suffered an 83%

drop in breeding population size from known historic levels

destruction of habitat can prevent recovery the fishing industry has begun to take faster-

growing varieties at lower trophic levels because of the fishing methods, almost 33% of

the fish caught are bycatch (dead or dying unwanted fish thrown overboard)

Fig. 13-2 Marine biodiversity

Fig. 13-3 Freshwater biodiversity

12-2 Importance of Wild Species

Wild species have value If species evolve, then why does it matter

that some go extinct? What’s the big deal? evolution takes a long time species are useful to us

economic value ecological value genetic value aesthetic value medicinal value recreational value

photography, bird watching, ecotourism some benefits have not yet been identified

12-1 Species Extinction

There are three types of species extinction local extinction: species no longer found

in one area but present in others ecological extinction: species can no

longer play its ecological role because so few are left

biological extinction: species is no longer found anywhere on Earth

Fig. 12-2 Some extinct species


Species are classified according to their risk species heading toward biological

extinction are either endangered or threatened

endangered species: species has few remaining individuals and could become extinct over all or most(?) of its range

threatened species: species is abundant, but declining numbers make it likely to become endangered in the near future

the first species to go tend to be economically valuable ones

Fig. 12-3a Some endangered species

Grizzly bear(threatened)

Arabian oryx(Middle East)

White top pitcher plant

Kirtland's warbler

African elephant(Africa)

Mojave desert tortoise (threatened)

Swallowtail butterfly

Humpback chub

Golden lion tamarin (Brazil)

Siberian tiger(Siberia)

Fig. 12-3b Some endangered species

West Virginiaspring salamander

Giant panda(China)

Knowlton cactus

Mountain gorilla(Africa)

Swamp pink

Pine barrens tree frog (male)

Hawksbill sea turtle

El Segundo blue butterfly

Whooping crane

Blue whale

Fig. 12-3c Some endangered species

Florida manatee

Northern spotted owl (threatened)

Gray wolf Florida panther Bannerman's turaco (Africa)

Devil's hole pupfish

Snow leopard(Central Asia)

Black-footed ferret

Symphonia(Madagascar)

Utah prairie dog(threatened)

Ghost bat(Australia)

California condor

Black lace cactus

Black rhinoceros(Africa)

Oahu tree snail

12-1 Species Extinction International Union for Conservation of

Nature and Natural Resources (IUCN-in your book “World Conservation Union”) is a leading authority on species conservation

IUCN categories as seen on Wikipedia:

Fig. 12-4 Characteristics of prone species

Fig. 12-5 Percent of species at risk by type

Percent of species at risk-IUCN Red List 07

Percent of birds at risk-IUCN(?) Red List 08


Biologists try to estimate extinction rates recall the terms background extinction

and mass extinction estimating current extinction rate is difficult

for several reasons 1. extinction takes a while 2. we have not identified every species 3. we know little about species we have

identified

12-1 Species Extinction IUCN monitors species (such as changes

in number or distribution) so that patterns can be detected

category of every species ideally re-assessed every 5 years (Wikipedia)

species-area relationship can be used to estimate extinction rates

based on observations of the correlation between number of species and the size of an area where they are found

Number of species per unit area


Humans are increasing the extinction rate the extinction rate has increased since the

arrival of humans 1,000 to 10,000 times higher extinction rate of 0.1% to 1% per year number of species going extinct (based on

these percentages) depends on number of species in the world

12-1 Species Extinction extinction rate of 0.1% to 1% per year

might be conservative 1. rate likely to increase this century 2. some areas (hot spots) have much higher

extinction rates 3. we limit speciation by degrading biologically

diverse environments (?) the rate could be too high because it is

based on inadequate data and sampling either way, more research is needed


fish are more threatened with extinction by humans than any other group of species

freshwater species are disappearing 5x faster than land animals

Fig. 13-4 Mean trophic levels of fish catch

12-3 Extinction Threats-Habitat Loss

Habitat loss and degradation are the greatest threats to species

12-3 Extinction Threats-Habitat Loss secondary factors:

habitat destruction and fragmentation major habitat disturbance factors:

agriculture commercial development water development outdoor recreation livestock grazing and pollution

invasive species pollution overharvesting

Indian Tiger

Range 100 years agoRange today(about 2,300 left)

Fig. 12-7a Effect of habitat loss

Black Rhino

Range in 1700Range today(about 2,400 left)

Fig. 12-7b Effect of habitat loss

African Elephant

Probable range 1600Range today(300,000 left)

Fig. 12-7c Effect of habitat loss

Fig. 12-7d Effect of habitat loss

Asian or Indian Elephant

Former rangeRange today(34,000–54,000 left)

12-3 Extinction Threats-Habitat Loss loss of terrestrial species is greatest in:

1. tropical forests (deforestation) 2. wetlands (filling) 3. grasslands (plowing) 4. islands

(island biogeography can help us understand the effects of habitat fragmentation)

12-3 Extinction Threats-Habitat Loss birds are in decline

70% of bird species are declining in numbers causes:

1. habitat loss and fragmentation 2. nonnative species (cats, rats, snakes,

mongooses, other birds) 3. pet trade (parrots) 4. human structures (fishing lines, phone

lines, buildings, etc.) 5. pollution

Fig. 12-8 Threatened U.S. songbirds

Florida scrub jay

Sprague’s pipit Bichnell’s thrush Blacked-capped vireo Golden-cheekedwarbler

Cerulean warbler

California gnatcatcher Kirtland’s warbler Henslow’s sparrow Bachman’s warbler


aquatic species are also threatened ~50% of world’s coastal wetlands were lost in

the last century coral reefs are severely damaged, mostly by

human activities >33% of mangrove swamps have disappeared

because of clearing for development, crops, and aquaculture

dredging and trawling are destroying many bottom habitats

scientists signed a statement to urge the UN to ban bottom trawling on the high seas

12-4 Extinction Threats-Nonnative species

Nonnative species can be beneficial, detrimental, or both we use nonnative species for food,

medicine, enjoyment (pets) nonnative species can displace or cause

the extinction of native species no predators introduce new diseases grow faster result: they decrease biodiversity

Fig. 12-9a Deliberately introduced species

Purple looselife European starling African honeybee(“Killer bee”)

Nutria Salt cedar(Tamarisk)

Marine toad Water hyacinth Japanese beetle Hydrilla European wild boar(Feral pig)

Fig. 12-9b Accidently introduced species

Sea lamprey(attached to lake trout)

Argentina fire ant Eurasian muffleBrown tree snake Common pigeon(Rock dove)

Formosan termite Zebra mussel Asian long-hornedbeetle

Asian tiger mosquito Gypsy moth larvae

1918

2000

Fig. 12-11 Argentina fire ant range

12-4 Extinction Threats-Nonnative species

prevention is the best way to reduce threats from invasive species

difficulties: small hard to detect breed rapidly

Fig. 12-12 Invaders and ecosystems


nonnative species are an increasing threat to marine and freshwater biodiversity

nonnative aquatic species arrive in ship ballast water

can be lessened by requiring ships to: discharge ballast water and replace it

with saltwater at sea before entering ports,

sterilize ballast water, or pump nitrogen into it


nonnative species are an increasing threat to marine and freshwater biodiversity

case study: purple loosestrife is a perennial plant that has invaded wetlands and greatly reduced biodiversity

two natural predators of loosestrife have been introduced from Europe where loosestrife is native

it will take time to determine whether this biological control approach works without the predators becoming pests

Fig. 13-5 Distribution of purple loosestrife

12-5 Extinction Threats-Poaching

Poaching is highly profitable huge profits and few penalties encourage

poaching (illegal killing or taking of wildlife) hunting (for food) can threaten wild species

when it is done for export as opposed to subsistence

increasing due to: (1) increasing population (2) accessibility to forests (3) restaurant demand (4) high profits

12-6 Other Extinction Threats

Killing predators, acquiring exotic pets and plants, and climate change and pollution affect ecosystems predators are killed because they bother us

or cause economic losses Carolina parakeet (eat fruit) elephants (trample) coyotes, wolves, bobcats (eat livestock or

poultry, popular game, or fish in farms) prairie dogs (make holes (not predator))

11-2 Conservation Biology

Humans have degraded much of the Earth conservation biology aims to analyze and

protect Earth’s biodiversity bioinformatics is the applied science of

managing, analyzing, and communicating biological information

species cataloging DNA analysis species ranges

The Species Approach The Ecosystem Approach

Goal

Protect species frompremature extinction

Strategies• Identify

endangered species

• Protect their critical habitats

Tactics

• Legally protect endangered species

• Manage habitat

• Propagate endangered species in captivity

• Reintroduce species into suitable habitats

Goal

Protect populations ofspecies in their naturalhabitats

Strategy

Preserve sufficient areasof habitats in differentbiomes and aquaticsystems

Tactics• Protect habitat areas

through private purchase or government action

• Eliminate or reduce populations of alien species from protected areas

• Manage protected areas to sustain native species

• Restore degraded ecosystems

Fig. 11-5 Protecting biodiversity

12-8 Protecting Wild Species: Sanctuary

Wildlife refuges can help protect species wildlife refuges set aside land for species gene banks (or seed banks), botanical

gardens, farms, zoos, and aquariums can help preserve species

important for education minimize need for wild species (farms) limited effectiveness

Fig. 12-15 Major migratory flyways

12-9 Reconciliation Ecology

Reconciliation ecology is a new form of conservation reconciliation ecology involves inventing,

establishing, and maintaining new habitats for species conservation in the areas where humans live and work

Fig. 12-16 Preventing premature extinction

12-7 Protecting Wild Species: Legal

Treaties and laws can help protect species international treaties

1975 Convention on International Trade in Endangered Species (CITES)

protects many species from commercial trade

limited effectiveness enforcement is difficult enforcement varies allows exemptions

12-7 Protecting Wild Species: Legal

Treaties and laws can help protect species international treaties

Convention on Biological Diversity 1992 signatory nations agree to inventory

biodiversity and develop a plan to protect it U.S. has not ratified it no enforcement

12-7 Protecting Wild Species: Legal national laws

Lacey Act of 1900 requires federal permit to transport live or

dead wild animals across state borders Endangered Species Act of 1973 (ESA)

identifies and legally protects endangered species (currently about 1260 species)

NMFS and USFWS list species forbids sale and purchase of any product

made from endangered species (including foreign species)

forbids federal agencies from harming endangered species or their habitats

12-7 Protecting Wild Species: Legal national laws, cont.

Endangered Species Act of 1973, cont. requires protection of critical habitat

some habitats have not been protected due to political pressure and lack of funds

controversial private versus public property rights issues

examples two types of freedoms: protection from

others, do what you want without government interference


Endangered Species Act of 1973, cont. applies to private land

steep fines and imprisonment for violations

incentives for private land owners habitat conservation plans (HCPs) can

help safe harbor agreements voluntary candidate conservation

agreements


Endangered Species Act of 1973, cont. The National Academy of Sciences

recommended three major changes in order to make the ESA more scientifically sound and effective

1. greatly increase funding to implement the act

2. develop recovery plans more quickly 3. when a species is first listed, establish

a core of its survival habitat that could support the species for 25–50 years

Fig. 12-14 Biodiversity hot spots in U.S.

13-3 Protecting and Sustaining Marine Bio.

Protection of marine life is difficult protecting marine biodiversity is difficult:

coastal development large inputs of sediment, nutrients, and

pollution damage not visible to most people lack of knowledge about ocean; view that

ocean is inexhaustible most of the ocean is outside the legal

jurisdiction of any country (resulting in tragedy of the commons)

Fig. 13-6 Threatened marine mammals


Laws, treaties, and education can help three sea turtle species are endangered

loss of onshore habitat taking of eggs used as food, medicine, jewelry, etc. unintentional catching

1000’s globally from long-line fishing 1000’s from U.S. shrimp trawling

reduced by turtle exclusion devices since 1989

Fig. 13-7 Major species of sea turtles


Laws, treaties, and education can help Convention on International Trade in

Endangered Species (1975) (CITES) Global Treaty on Migratory Species (1979) U.S. Marine Mammal Protection Act (1972) U.S. Endangered Species Act (1973) U.S. Whale Conservation and Protection

Act (1976) International Convention on Biological

Diversity (1995)

Fig. 13-8a Toothed whales

Fig. 13-8b Baleen whales


Some countries want to overturn the 1970 whaling ban International Whaling Commission (IWC)

est. 1946 (now has 49 member nations) established quotes for whaling did not work because

quotas based on inadequate data or ignored no powers of enforcement

U.S. banned all commercial whaling and imports of whale products in 1970


Some countries want to overturn the 1970 whaling ban U.S. and many nonwhaling countries in

IWC imposed a moratorium on commercial whaling in 1986

42.5 k killed in 1970, 1.2 k in 2004 Japan, Norway, and Iceland still hunt whales

traditional “moratorium based on emotion, not science” why not if there are over 1 M whales?


Some countries want to overturn the 1970 whaling ban

some conservationists disagree “whales are peaceful” “whales are intelligent” “whales are sensitive” “whales are social” inaccuracy of estimates limited whaling will open the door to

approval and weaker laws


Some marine sanctuaries exist but not many national control of oceans

sovereignty to 12 miles offshore (U.N. Law of the Sea)

jurisdiction to 200 miles offshore (Exclusive Economic Zone (EEZ))

not much of that area (36% of ocean surface and 90% of fish stocks) is protected

IUCN has helped establish marine protected areas (MPAs) since 1986


Other solutions integrated coastal management

zone land and sea portions of an entire coastal area

reconciliation ecology

13-5 Protecting, Sustaining, and Restoring Wetlands

Coastal and inland wetlands are important reservoirs of aquatic biodiversity; they provide ecological and economic services a law that requires a permit to fill or deposit

dredges into wetlands has cut wetland loss by 80% between 1969 and 2002


a study by the National Academy of Sciences found that mitigation banking, the destruction of a wetland as long as an equal area of the same type is created or restored, does not work very well; these projects often fail to meet the standards set for them

Fig. 13-10

Legally protect existing wetlands

Steer development away from existing wetlands

Use mitigation banking only as a last resort

Require creation and evaluation of a new wetland before destroying an existing wetland

Restore degraded wetlands

Try to prevent and control invasions by nonnative species

Protecting Wetlands

Solutions


case study: Everglades natural Everglades are half their original size

and are drying out, leaving them vulnerable to fire and invasion by nonnative species

Everglades NP was set up in the lower part of the Everglades, but water did not flow into it and human activity caused disturbances

90% of the wading birds are gone, and other vertebrates are reduced in number by 75–95%

Florida Bay has become saltier and warmer loss of water flow and input from crop fields

and cities have caused large algal blooms harm coral reefs, tourist industry


case study: Everglades, cont. the U.S. Army Corp of Engineers has begun a

restoration project funded by the state and the federal government to restore the river and flow of water to the Everglades; goals:

restore curving flow of more than half of the Kissimmee River

remove 250 miles of canals and levees south of Lake Okeechobee

buy 93 square miles of farmland and allow it to flood to create artificial marshes

create a network of artificial marshes


case study: Everglades, cont. project goals, cont.

create 18 large reservoirs to ensure water for south Florida’s present and future population and the lower Everglades

build new canals, reservoirs, and pumping stations to capture and return to the Everglades 80% of the water flowing out to sea

miles

kilometers

0

0

20

20

40

40 60

60

( )

( )

GULF OF

MEXICO

Naples

Fort Myers

FLORIDA

Florida Bay

Everglades

National Park

Key Largo

ATLANTIC

OCEAN

Miami

FortLauderdale

WestPalmBeach

LakeOkeechob

ee

Unchannelized

Channelized

FLORIDA

Area of

detail

Agricultural area

Treatment marshWater

conservation areaCan

al

Kissimmee

River

Fig. 13-11

13-6 Protecting, Sustaining, and Restoring Lakes and Rivers

invasions by nonnative species have upset the ecological functioning of the Great Lakes for decades at least 162 nonnative species have

invaded the Great Lakes since the 1920s sea lampreys have depleted a number of

the sport fish species in the lakes


nonnative species in Great Lakes, cont. zebra mussels were brought into the lakes

in ballast watervery aggressive pests (no known natural enemies)displaced native mussel speciesclogged pipes and piersfouled beachesspread to other parts of the U.S.


rivers/streams are important ecological and economic resources degraded by overfishing, pollution, dams,

and water withdrawal case study: salmon in Columbia River

salmon are migratory fish that breed in the upper reaches of the river and its tributaries

need free flowing water to return, spawn, and lay eggs where they hatched

benefit nearby forest as fertilizer as bears eat and discard carcasses on the forest floor

trees grow up to 3x faster along streams with salmon than those without


case study: Columbia River, cont. threats to salmon:

many dams on Columbia River overfishing in the Pacific Ocean destruction of spawning grounds by

sediment and lack of trees (makes water too warm for eggs)

water withdrawal release of farm raised salmon (could

decrease genetic diversity) result: 94% drop of wild Pacific salmon, and

nine species of Pacific Northwest salmon are endangered or threatened

Fig. 13-13

Fig. 13-14

Fish change form

Fish enter riversand head forspawning areas

Grow to smoltand enter the ocean...

Grow to maturityin Pacific Oceanin 1-2 years

Eggs and young arecared for in the hatchery

Fry hatch in the spring...

Fingerlings migrate downstream

In the fall spawning salmondeposit eggs in gravel nests

and die

NormalLifeCycle

Fingerlingsare released into river

And grow in the stream

for 1-2 years

Human capture

Salmonprocessingplant

Eggs are taken from adultfemales and fertilized withsperm “milked” from males

ModifiedLifeCycle

To hatchery


case study: Columbia River, cont. solutions:

The Northwest Power Act was passed in 1980; goals:

meeting electricity needs of the region restoring salmon, other fish populations these two goals often conflict

people are working together to try to solve the conflicts in this large-scale reconciliation project

critics say that the wild salmon populations are stable in Alaska, so we should not worry about the wild salmon of the Pacific Northwest

Solutions

Rebuilding Salmon Populations

Building upstream hatcheries

Releasing juvenile salmon from hatcheries to underpopulated streams

Releasing extra water from dams to wash juvenile salmon downstream

Building fish ladders so adult salmon can bypass dams during upstream migration

Using trucks and barges to transport salmon around dams

Reducing silt runoff from logging roads above salmon spawning streams

Banning dams from some stream areas

Fig. 13-15


sustainable management of freshwater fish involves encouraging populations of commercial/sport fish species, preventing overfishing, and reducing or eliminating less desirable fish populations

1. regulate fishing seasons and the number and size of fish taken

2. improve habitats, breed genetically resistant fish varieties, and use judicious amounts of antibiotics and disinfectants to control predators, parasites, and diseases are methods suggested

3. some individuals have worked to restore degraded streams


the National Wild and Scenic Rivers Act was passed in 1968 to protect rivers and river segments with outstanding scenic, recreational, geological, wildlife, historical, or cultural values

Congress established a three-tiered classification scheme

wild rivers are relatively inaccessible; they are not permitted to be widened, straightened, dredged, filled, or dammed

scenic rivers are free from dams, mostly undeveloped, of great scenic value, and accessible in some places by roads


the National Wild and Scenic Rivers Act, cont.

classification, cont. recreational rivers are readily accessible

by roads and may have some dams or development along their shores

only 0.2% of the 3.5 million miles of rivers are protected under the Act, and 17% of the total river length has dams and reservoirs on them

environmentalists want to add 1,500 additional river segments for a total of 2% of the total river systems; there is opposition


threats to aquatic biodiversity are real and growing

we must greatly increase research and expand efforts to protect and restore aquatic biodiversity and promote integrated ecological management

Natural Capital

Ecological Services of Rivers

•Deliver nutrients to sea to help sustain coastal fisheries

•Deposit silt that maintains details

•Purify water

•Renew and renourish wetlands

•Provide habitats for wildlife

Fig. 13-12

Documents

Area VII: Global Change VIIC: Loss of Biodiversity