sustaining wild species chapter 16. review: explain the difference in genetic diversity, species...

Sustaining Wild Species Chapter 16

Review: Explain the difference in

genetic diversity, species richness, and ecosystem diversity.

What is Biological Diversity?

• What changes have occurred to change the biodiversity of the earth?– Background extinction– Mass extinction– Adaptive radiation

• What is different today?

Importance of Biodiversity• Biologist estimate that for every 2,000

species that have ever lived, 1,999 of them are extinct today.

• Currently species extinction is occurring at a rate of 100 to 1,000 times the natural rate of background extinction.

Why are Alligators Special?• Using figure 16.2 in your text book, list the

role alligators play in their environment.• What is the name for the role the alligator

plays?• __________ _________ within an ecosystem

provides the ecosystem with resilience, the ability to ______________.

Importance of Biodiversity

Economic: crop strains such as the winged bean plant (page 355), paper, fiber, dyes, lumber, oils

Importance of BiodiversityMedical: drug source, testing for toxicity and

drugs/vaccines• 80% of the world’s population relies on plants or

plant extracts for medicines.• At least 40% of all pharmaceuticals come from the

genetic resources of wild plants, mostly tropical developing countries. Example: anticancer drugs

• Rosy periwinkle produces chemicals that are effective against certain cancers --- childhood leukemia (page 354)

Importance of Biodiversityscientific knowledge: how life evolved and

functions genetic engineering – the incorporation of genes

from one organism into an entirely different species.

*We have skills to transfer genes from one organism to another but we do not have the ability to make genes that encode for specific traits. Why destroy the genetic diversity when it may hold the solutions?


Ecological services: nutrient cycling, pollination, soil fertility, oxygen production, climate moderation, waste recycling, detoxification, pest control, gene pool/evolution

Remember Earth’s Capital????


Aesthetic and Recreational• Ecotourism: wildlife

tourism• Americans spend 3 times

more to watch wildlife than to go to movies or on professional sporting events

Why Use the Precautionary Principle?

Aldo Leopold (page 353)• we have little understanding of the ecological

roles of the world’s identified 1.75 million species • use precautionary principle to prevent the

premature extinction of species as a result of our activities . Estimates are that on average 50 - 200 species per day become extinct (above the background extinction rate)

Keystone species A species that is crucial in determining the

nature and structure of the entire ecosystem in which it lives; other species of a community depend on or are greatly affected by the keystone species, whose influence is much greater than would be expected by its relative abundance.

These are most vulnerable to habitat loss.


Ecosystems may lose their ability to support many forms of life because of the disappearance of local populations of key organisms


Mathematical models indicate a time lag of several generations between habitat loss and extinction, primarily because habitat loss also removes potential colonization sites….

If this is true, biologist may be grossly underestimating the magnitude of the current biodiversity meltdown!

Three Levels of Extinction Local Extinction: when a species is no longer

found in an area it once inhabited but is still found elsewhere in the world.

Three Levels of ExtinctionEcological Extinction: Where there are so few

members of a species left that it can no longer play its ecological roles in the biological communities where it is found.

Sea Otter

Three Levels of Extinction Biological Extinction: Occurs when a species is

no longer found anywhere on the earth. Biological extinction is FOREVER!!!

Endangered vs. Threatened

• What is the difference in the terms endangered and threatened?

• Endangered: has so few individual survivors that the species could soon become extinct over all or most of its natural range.

• Threatened: still abundant in its natural range but is declining in numbers and is likely to become endangered. Examples: grizzly bear, southern sea otter, American alligator

Estimated extinction rate

Estimated Extinction Rates

• Average annual extinction rate of Mammal and Bird species– 8000 B.C - A.D. 1600 1 species per 1000– 1600 – 1900 1 species every 4 years– 1900 – 1975 1 species every year

Estimated Extinction Rates

• Extinction rate of All Species– 1975 several hundred– 1985 several thousand– 1990 at least 10,000– 2000 20,000 – 50,000

Threatened

Endangered

Extinct

Ten Characteristics of Extinction-Prone Species

• found in limited areas• small population size• low population density• large body size• specialized niches and feeding habits --- Giant

Panda (bamboo)• low reproductive rates


• fixed migrations Flyway – An established route that ducks, geese,

and shorebirds follow during their annual migrations.


• feed at the top of long food chains or webs• have high economic value to people• need large territory : The California Condor (page 357)

Snow Leopard Coat

Three Root Causes of Extinction of Wildlife:

• human population growth• economic systems that don’t value

the environment• exploitation, degradation of wildlife

habitats

Eight Human Activities Which Directly Increase the Wildlife Extinction Rate:

• population growth• poverty• habitat loss Example: Figure 16.9, page 360 The dusky

seaside sparrow found only in the marshes of St. Johns River in Fla. became extinct in 1987 due to human destruction of its habitat.

What Type of Feedback Loop?


• habitat fragmentation• hunting/poaching (Carolina Parakeet, Prairie

Dog)

Problems with Habitat Fragmentation

• Increase exposed surface are making species vulnerable to predators, fires, etc

• Patches are too small to support minimum breeding population

• Fragmentation can create barriers that limit the ability of some species to disperse and colonize new area, find enough to eat, and find mates

Critical population density

• Must have minimum viable population size: below this number the species’ survival may be jeopardized because males and females have a difficult time finding each other. Problems are:– Death rate exceeds birth rate as population falls

below its critical size– Remaining small population can easily be wiped

out by fire, flood, disease

Critical population density

• Genetic diversity also decreases because the resulting smaller gene pool and inbreeding reduce population’s ability to respond to environmental changes through natural selection

• An endangered species must number at least 10,000 and often more to maintain its evolutionary potential for survival.


• uses as pets/ decorations• climate change/pollution


• introduced species (alien species) Examples: Kudzu, Brown Tree Snake, Blue Water Hyacinth**Be familiar with examples of introduced species to the US (table 16.1 page 360)

Frogs…..• Bioaccumulation

• Biomagnification

Facts to Know

• Species is considered extinct when it has not been seen for at least 50 years or when the last of a few monitored individuals die.

• endemic species: Found no where else on earth

• range: The area in which a particular species is found

Bioinformatics

• Organizing and storing useful biological information about wild species using a data base

• Provides computer tools to find, visualize, analyze, and communicate biological information

BiophiliaAn inherent affinity for the natural

world (love of life)

.

Facts to Know

• Commercial extinction: Depletion of the population of a wild species used as a resource to a level at which it is no longer profitable to harvest the species.

• Where is declining biological diversity the greatest problem?

Florida, California, Hawaii Hawaii is #1

Facts to KnowBiodiversity Hotspots: Describes relatively small areas of land that contain an exceptional number of endemic species and are at high risk from human activities.(Page 359 figure 16.8)

Human Causes of Species Endangerment

Give three examples of:– habitat destruction, habitat

fragmentation, or habitat degradation– invasive species (biological pollution)–pollution–overexploitation

How Important is the Tropical Rainforest?

• Cover 7% of the Earth’s surface but has as many as 50% of the Earth’s species inhabit them

Tropical Deforestation and Degradation

Primary causes– Rapid population growth– Poverty– Exploitive government policies– Exports to developed countries– Failure to include ecological services in evaluating

forest resources

Tropical Deforestation and Degradation

Secondary causes

– Roads - Mining– Cattle ranching - Cash crops– Logging - Oil drilling– Tree plantations– Flooding from dams– Unsustainable peasant farming

What Happens When Tropical Rainforest Are Destroyed?

• Birds that migrate from North America to the rain forest in Central America and the Caribbean have been declining in numbers faster than other migratory birds

• The forest itself generates much of the rainfall in tropical rain forest. If half of the existing rain forest in the Amazon region of South America were to be destroyed, precipitation in the remaining forest would decrease.

What Happens When Tropical Rainforest Are Destroyed?

• As the land became drier, organisms adapted to moister conditions would be replace by organisms able to tolerate the drier conditions. Many endemic species would become extinct.

• Disruption of the evolutionary process. – Tropical Rainforest has supplied the base of ancestral

organism from which adaptive radiation occurs.– Are we eliminating nature’s ability to replace its

species through adaptive radiation?

Overfishing

• Tragedy of the commons???• Commercial fishing methods

Bycatch• Bycatch is the term used for the accidental capture of

non-target species in fishing gear. Humpback whale entangled in a fishing net.

Bycatch

Conservation Biology

The scientific study of how humans impact organism and the development of ways to protect biological diversity.

Conservation Biology• What are the concepts that guide it?

– Large habitats are more effective at safeguarding species that several habitat fragments

– Large areas of habitat typically have the potential to support greater species richness.

– It is better if areas of habitat for a given species are located close together rather than far apart.

Conservation Biology

– Areas that are inaccessible to humans are better than human accessible areas.

– It is more effective and more economical to preserve intact ecosystems in which many species live than to work on preserving individual species one at a time.

– Higher priority is given to preserving areas that are more biologically diverse than others. (Remember the Hot Spots?)

Three Techniques of Conservation Biology

1. Ecosystem Approach• In situ conservation

– Protecting habitats– Restoring damaged or destroyed habitats– Preserve balanced populations of species in their

native habitat– Establish legally protected wilderness areas and

wildlife reserves– Eliminate or reduce the populations of nonative

species


2. Species Approach• Identify endangered species and give them legal

protection• Preserve and manage crucial habitats• Ex situ conservation

– Zoos, aquarai, botanical gardens, seed banks• Reintroducing endangered species to nature


3. Wildlife Management Approach• Manages game species by:

– Using laws to regulate hunting– Establishing harvest quotas– Developing population management plans– Using international treaties to protect migrating

game species such as waterfowl

Wildlife Refuges

• Teddy Roosevelt established Pelican Island off Florida’s Atlantic coast as the 1st wildlife refuge to protect the brown pelican (1903)

• Now have 508 refuges, 85% are in Alaska• ¾ are wetlands for protection of migratory

waterfowl

Laws, Acts, and Organizations• CITIES• Lacey Act• Endangered Species Act• Wild Bird Conservation Act• Magnuson Fisheries Management and

Conservation Act

United States

• Lacey Act (1900) – Prohibits transporting live or dead wild animals or

their parts across state borders without a federal permit

• Endangered Species Act (1973)– Endangered or threatened species cannot be

hunted, killed, collected or injured in the United States

The Endangered Species Act

• There are over 1100 species on the list – 60% are plants and 40 % are animals. Hawaii leads this list (298+). Each year about 85 species are added to the list

• Requires all commercial shipments of wildlife and wildlife products enter or leave the country through one of nine designated ports.


• National Marine Fisheries Services (NMFS) identifies and list endangered and threatened ocean species.

• U.S. fish and Wildlife Service (USFWS) identifies and list all other endangered and threatened species.

• Adding or removing a species from the list must be based on biology, not economic or political reasons


• Forbids federal agencies to carry out, fund, or authorize projects that would either jeopardize, destroy or modify the critical habitat.

• Fines and jail sentences can be imposed on private lands to ensure protection of the habitats of endangered species.

Rules of the Endangered Species Act

• There are over 1100 species on the list – 60% are plants and 40 % are animals. Hawaii leads this list (298+). Each year about 85 species are added to the list

• Requires all commercial shipments of wildlife and wildlife products enter or leave the country through one of nine designated ports.

Wild Bird Conservation Act

• Imposed a moratorium on importing rare bird species

Magnuson Fisheries Management and Conservation Act

• Gives the federal government authority to manage fisheries in the zone between 3 and 200 miles off the U.S. shore. There is no limit on the number of U.S. fishing vessels, but quotas can be imposed on the quantity of fish taken.

Other Solutions

• Biosphere Reserves

• Reintroduction of endangered species– Restoration Ecology