What is biodiversity and how is it measured?

• What is Biodiversity?– The variation that exists in the natural

world at all levels of biological organization– All organisms in a defined area, all of their

variations and all of their interactions with each other and with the physical environment

Levels of Biodiversity

1. Genetic diversity: the gene pool within a population

2. Species diversity: the number and types of species in an area

3. Higher taxonomic diversity

4. Community Diversity

5. Ecosystem diversity (Habitat diversity)

Species diversity has two components:

1. Species richness: how many different species are present in a habitat

2. Relative abundance: total number of individuals of each species present

Species Richness and Abundance of a Swamp Forest on Maryland’s Eastern

Shore

4%

6%

8%

14%

17%

18%

33%

7. American Beech

6. Loblolly Pine

5. American Holly

4. Oaks

3. Sweet Gum

2. Black Gum

1. Red Maple

2003

Species diversity has two components:

1. Species richness: how many different species are present in a habitat

2. Relative abundance: total number of individuals of each species present

3. Which area is more diverse?

Defining Biodiversity:

• Old growth forest in the Shenandoah Mountains of Virginia – 50,000 trees represented by 10 species.

• Managed forest, recently clear cut– 45,000 trees are maple and birch– Only 1/10th of the forest is represented by

the remaining 8 species

Importance of TaxonomyNaming Species

1. Naming things upon which we depend for food and medicine means survival.

2. Important to measuring biodiversity

3. Conservation

Basics About TaxonomyKingdom

Phylum or Division

Class

Order

Family

Genus

Species

Most inclusive category

Least inclusive category

Linnaeus (1707 -1778)

Taxonomy

Linnea borealisTwin Flower

Binomial Nomenclature

Felis domesticus L.

Genus Species epithet Author

The house cat

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Carnivora

Family: Felidae

Genus: Felis

Species: Felis domesticusClassification & Taxonomy

“Wild”Felis sp.

Felis pardalisOcelot

BobcatLynx rufus

Panthera tigris

Panthera leo

Puma concolor

Other Genera of the Cat Family

Family:Felidae

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Carnivora

Family: Felidae

Genus: Felis

Species: Felis domesticusClassification & Taxonomy

Suborder: Aeluroidea

Order: Carnivora

Suborder: Arctoidea

Pinnipedia

Otariidae -- sea lions, eared seals, fur seals

Odobenidae -- walrus

Phocidae -- true (earless) seals, elephant seals

Canidae -- dogs, wolves, foxes, coyotes, dingos

Ursidae -- bears, panda

Procyonidae -- raccoons, kinkajous, ringtails, coatis

Mustelidae -- weasels, ferrets, skunks, badgers, otters, sea otter

Suborder: Aeluroidea

Viverridae -- mongooses, meercats, civets, linsangs

Hyaenidae -- hyenas, aardwolf

Felidae -- cats, lions, tigers, leopards, cheetah

FYI

Aeluroidea

Kingdom Animalia Animalia

Phylum Arthropoda Chordata

(Vertebrates)

Class Malacostraca Mammals

Order Decapoda Primates

Family PORTUNIDAE swimming crabs

Hominids

Genus Callinectes Homo

Species Callinectes sapidus

The Blue Crab

Homo sapiens

Eubacteria

Archaebacteria

Animal

Fungi

Plant

Protist

Commonancestor

Domains:

Kingdoms:

Eubacteria Archaea Eukarya

Domains and Kingdoms

Eubacteria &Archaebacteria

ProtistaAlgaeSlime moldsProtozoa

FungiTrue fungi

PlantsBryophytesVascular Plants

AnimalsMulticellularanimals

Absorb food in solution

photosynthesis

Ingest food

Food Requirements

chemosynthesisphotosynthesis

chemosynthesisphotosynthesisIngest food

Kingdom

What you need to know about Classification

• The order of classification

• Binomial nomenclature (genus, species)

• The three Domains

• The five Kingdoms

• The ecological role of each kingdom

• The scientific name of the Blue Crab

Rich in Species, Poor in Knowledge

E.O. Wilson estimated 1.75 million species are living on the planet. Scientists generally disagree with the exact number but, agree with Wilson that 1.4 M represents probably a mere 1/10th of the total diversity.

Why do we know so little?

Other estimates:4-112 million (7 million)

Number of Living

Species of All Kinds of

Organisms Currently

Known

Insects54%

Other Animals 20%

Bacteria 4%

Fungi 5%

Algae 2%

Plants 18%

Protozoa 2%

What do we know?• Estimates of the # of species

• More species are located in the tropical regions of the world– 2/3rd – 3/4th of all species live in tropical rain

forests which cover only 7% of the earth’s surface

Diversity of North and Central American birds

Why do we know so little?

1. Not all species have been discovered– #’s are biased toward animal species– Know more about species in developed Nations– Not all species are named as a result of unclear

species concepts in taxonomy

2. On-going extinction: species loss in tropical forest is estimated at 6000/year,

• Tropical rain forests are more species rich than northern regions of the world

• What are some factors that might account for this?

Some factors that affect the biodiversity of an area

1. Historical Events– Time

2. Habitat conditions

3. Habitat structure

4. Climate stability

5. Competition– Predators– Keystone species

6. Disturbance

1. Historical Events• Each part of the world

has a unique history• Effect of the recent

Ice Age in the northern hemisphere– Ireland has no snakes

• Time: Older Areas have more species than younger areas

Extent of Glaciation in the Pleistocene

2. Habitat Conditions

• Areas with extreme climate or conditions harbor fewer species

• Soldiers Delight Natural Environment Area (NEA) is comprised of 1,900 acres of serpentine barren. The area has over 39 rare, threatened, or endangered plant species as well as rare insects, rocks and minerals.

• Delaware River and Pollution

3. Habitat Structure• Terrain that is simple, uniform, and

without much physical variation tends to have fewer species than a complicated terrain with wet and dry spots

• Ecologists call these microhabitats• A piece of property with a patch of forest,

a small wetland, and a field with harbor a greater diversity than the same sized property that is covered with only forest.

3. Habitat Structure: The Forest Community

stratification

• The canopy

• The shrub layer

• The understory

• The herbaceous layer– most conspicuous in the spring

• The forest floor

4. Climate Stability• How do the Tropics differ in climate

from Temperate regions?

5. Competition Among Species

• Predators can enhance an area by reducing the population size of prey species

• Other species have a chance to get established

• Keystone Species have a large effect on the other species of a community– Oysters of the Chesapeake Bay– Vital as water filters, provide habitat, income

for watermen

6. The Nature of Disturbance

1. Damage communities

2. Remove organisms

3. Alter resource availability

FireFlooding

Storms and HurricanesTornados

Ice Storms

6. Disturbance

1. Create opportunities for the colonization of new species

2. Disturbance is a natural part of the life of a community: most communities are always in recovery from disturbance

3. Humans as agents of disturbance

Hurricane Katrina

• Cypress trees play a crucial role in the swamp forests that cover hundreds of thousands of acres of coastal Louisiana. These swamps prevent floods by collecting storm waters and clean water by filtering out pollution. They also provide habitat for a wide variety of animals, such as migratory songbirds (the ivory-billed woodpecker, until recently believed extinct, once thrived in the swamps).

FIREYellowstone fires of 1988

Fire has been used to manage marshes and forests

Optional ActivityUnit 3: Activity 31

Track Your UnderstandingAnswer Question #2 on pages 464-465

worth 5 points

Species Extinction:Past and Present

• Extinction is a biological reality• Extinction and evolution are intricately related• Five mass extinctions in the earth’s history

– 99% of species that have ever existed are now extinct

• Each mass extinction is followed by a rise in biodiversity of a new set of species

Humans Agents of Extinction

• Humans have played a role in the extinction of species for thousands of years

• Some say we are facilitating the 6th mass extinction in the earth’s history

• Can scientists accurately measure extinction rates?

Estimates of Extinction Rates“the logic of loss”

• Estimating rates is difficult at best• Most accurate estimates are for birds

and mammals• Species-area relationships from Island

Biogeography– # species is related to size of habitat– Estimate habitat loss– 90% habitat loss: 50% species loss

Island Biogeography:Species richness and island size

Conserving the Biodiversity of the Commons

• Conserving the world’s biodiversity is based on principles of biology– Population biology – Conservation biology

Principles of Population Biology

1. Small populations are more likely to become extinct than large populations

2. To understand a population it is important to consider factors such as its age structure and sex ratio

3. Populations must be monitored to determine the effects of a conservation plan

Principles of Conservation Biology

1. A species that is broadly distributed across its range is less likely to become extinct than a species that is restricted to a small part of its range

The range of the Eastern Fox Squirrel

• The Delmarva Fox Squirrel

• Original range included the entire Delmarva peninsula into southeastern PA.

• Remnant populations exist at Blackwater, Eastern Neck NWR (Kent Co.), and Assateague Island

Principles of Conservation Biology

2. Characteristics of habitats that favor species preservation:

a. Large rather than small; Bigger is better

b. Close together rather than far apart

c. Whole rather than internally fragmented

d. Linked by corridors rather than isolated

e. Inaccessible rather than easily accessible to people

• Island Biogeography (studying populations on islands) teaches us about conservation on main lands

• Why?• Habitat

fragmentation• Example

fragmenting a forest

• The main land of South America is to the Galapagos Islands as

• An intact forest is to the fragmented parcels

Dooms species by confining them to small, island-like parcels of habitat surrounded by an ocean of human impact. This often leads to: – Inbreeding within small populations– Roads, fences, houses, clear-cuts create

barriers to dispersal and reproduction– More susceptible to environmental

fluctuations and catastrophes

When habitats become islands

Habitat Loss and Fragmentation for Real

Corridors are Important for Connecting “Islands”

• Corridors function as pipelines that permit wildlife to move between habitats

• Promote biodiversity• But can also transmit disease, fire, predators, and

pests• The effectiveness of habitat corridors depends on the

situation

Agriculture with Forested Corridors

Algonquin to Adirondack

Wildlife Preservation Project

Fragmentation of Habitat in Maryland

• Early tobacco farming in the Mid-Atlantic resulted in fragmentation of the land into a fine mosaic of forest patches interspersed with young trees, herbs and shrubs.

• Large scale agriculture stripped extensive areas of the landscape leaving only small patches of forest

• The most extensive land clearance in the region occurred in the late 1800’s – early 1900’s

• 80% of the land around the Chesapeake was cleared of its forests.

• Wetlands were drained for farm land.

• The pattern of farm fields, forests, and marshes surrounding Blackwater Wildlife Refuge

• Dorchester Co. Eastern Shore

• Blackwater Wildlife Refuge’s Wildlife Drive is circled