Lecture 56

Lecture 56

Hawaii’sBiodiversity

Environmental Diversity

Extremely wide range of habitats

temperature

moisture

soils

vegetation

Environmental Diversity

Cold & Dry

Cool & Dry

Warm & Wet

Hot & WetHot & Very Dry

Warm & Very Dry

Warm & Dry trades

inversion

Facts:• 2,500 miles of ocean separate North

America from the Hawaiian Islands.• 3,500 miles of ocean between the

small Marianas Islands and the Hawaiian chain.

• The Hawaiian chain has never been connected to a land mass.   

How then, did plants and animals cross the large oceanic distance to arrive on the Hawaiian islands? 

• Transportation through the air• Attached to Birds• Fruits eaten by Birds• Drifting in Seawater

Hawaii’s Flowering PlantsHawaii’s Flowering Plants

Long Distance Dispersal Wind, Water, & Wings Theory

The original colonist plants arrives in the following ways:

water 23%

wind 2%

birds 75%

14.3% of native flowering plants adapted to oceanic drift.

Adaptations for dispersal in seawater:• Seeds or fruits capable of floating.• Seeds or plant parts must be able to resist seawater for

weeks.• Must arrive alive on beach and be able to grow there. 

Pandanus tectorius

Includes plants that reproduce by means of spores such as ferns, mosses, algae, and lichen

• Spore size: Spores so small that a line of a thousand of them end-to-end would be an inch long.

• Fern spores would be more successful at reaching Hawaiian island then seeds of flowering plants.

Adenophorus periens

• 1.4% of the 255 hypothetical original flowering plants were dispersed by air flotation

• Ohia lehua tree has seeds small enough to suggest dispersal through the air. 

1st to appear after a lava flow Metrosideros polymorpha

Insects.

• Passive flight and small body size of insects accounts for their dispersal to the island.

Yellow-faced beeNesoprosopis

pollinates

• Embedded in mud on feet or other parts of birds

• Sticky substances

• Mechanical devices (barbs, hooks, bristles)

Pacific golden plover

• Most effective means of seed dispersal to the Hawaiian Islands.

• Accounts for dispersal of an estimated 39% of the 255 hypothetical original plants.

Tetraplasandra flynii

Has hairy gray fruits

migrationmigrationmigrationmigration

Flowering Plant Dispersal by Birds

Birds • Travel through active flight such as

migratory birds, marine birds, shore birds and waterfowl.

• Land birds underrepresented.

Insects• Passive flight and small size

• Storms

• Air currents

• Migration

Fish • Freshwater fish, gobie family (diadromous or

amphidromous))

• Drift as larvae (long-lasting stage)

Marine inverts• Drift as larva Ocean currents and gyre

Most from Northwest Pacific

Islands act as stepping stones

Amphidromous- migrate to and from the sea but do not use the ocean for reproduction

Anchialine pond

Immigration Rates

number rate (1 every …)flowering plants 272 110 thousand yearsinsects 275 110 thousand yearsland snails 25 1.2 million yearsland birds 15 2 million yearsmammals 1 30 million years

Biodiversity

Number of species

Native (got here “naturally”

or evolved here)

Endemic (found only here)

Alien (exotic, human introduction)

NATIVE

Occurring naturally in a given geographic area; not introduced

as a consequence of human activities

Turkey fish

ENDEMIC

Occurring exclusively in a given geographic area, having

originated in that area through natural means.

Hawaiian Cleaner Wrasse

Hawaiian Honeycreepers

Hawaiian Crickets

Pueo

Hawaiian Hawk (Io)

Hoary Bat (Opeapea)

Hawaiian Monk Seal

Unusual Insects & their Relatives

Happy Face Spider

Tree Snails

Nene

Ohia Lehua

Hapu Ferns

Percent Endemism in the Hawaiian Islands

Marine Algae

Ferns & Fern Allies

Mosses

Flowering Plants

Terrestrial Mollusks

Marine Mollusks

Insects

Mammals

Birds

Plant or AnimalGroup

?

ca. 25

114

225

ca. 270

24 - 34

?

230 - 255

2

EstimatedNo. of

Colonists

420

ca. 135

145

233

ca. 1000

ca. 1000

ca. 1000

5,000

2

EstimatedNo. ofNative

Species

13

81

70

46

91

99

30 - 45

99

100

%EndemicSpecies

Endemic and Native Wildlife of the Hawaiian Islands

EXOTIC

Introduced to a given geographic area as a

consequence of human activities.

Anemone fish

Speciation

Flowering PlantsFlowering Plants

9% of immigrants

adaptive radiationadaptive radiationnew species

migrant species

Results of Speciation

colonists species radiationflowering plants 270-280 956 91insects 233-254 3,722 81land snails 23-24 1,064 294land birds 15 70 42

radiation = maximum species from 1 colonizing species

Gaps in Speciation

Metrosideros polymorpha (ohia)

1 tree species dominates

Fills many ecological roles

Ordinarily, there would be many species

Metrosideros polymorpha

Honeycreepers

No woodpeckers (recently introduced?)

No hummingbirds

Gaps in Speciation

No native large herbivores

Plants with:

No thorns (berries)

No stingers (nettles)

No chemical defenses (mint)

Gaps in Speciation

How do they arrive?

Dispersal Methods:• Rafting• Hitchhiking• Currents • Storms• Migrating Islands

Invasive Species Pathways Purposeful introduction via legal and illegal means; Unintentional introduction• Aircraft and cargo ship hulls• Ballast water and ship cargo• Hand-carry/luggage• Agriculture experiment stations• Mail• Forestry activities• Horticulture trade• Aquaculture• Pet trade• Botanical gardens

WHY SOME INTRODUCTIONS SUCCEED AND SOME DON’T?

Disadvantages due to new environmental conditions:

• Foraging & predator avoidance strategies may be different

• Small #’s of orgs introduced may go extinct

Advantages:Generalist vs specialist species

Polynesian Voyagers to Hawaii

taro

breadfruit

kava

yam

Ahupua’a

1. Upland2. Plains3. Ocean

Ranges from the tip of the mtn to the reef area

Slash & burn agriculture (swidden)

Hawaii Bird Biodiversity Crisis

• Half of Hawaii’s native birds went extinct soon after the Polynesians arrived

• Half of the remaining species of birds went extinct soon after Captain James Cook arrived

European Contact

Large herbivores introduced

Native plants are “ice cream”

Animals multiplied rapidly

Introduced Feral Mammals

Goats

1.5 million skins 1844-1900

Cattle on Oahu

Wandered Honolulu streets

On all land but residential, agricultural or dense forest

MongooseBrought in to help control rat population in sugar cane fields

• Rat nocturnal• Mongoose diurnal

Mongoose, dogs, and cats are the nene’s main predator

Caribbean frogCaribbean frogcoqui

coqui

coqui

coqui

coqui

coquicoqui

Feral pigsFeral pigsOriginally introduced by Polynesian voyagers from the Marquesas Islands ca. 400 AD

Two Piranhas were caught in Lake Wilson in 1992-93. There may be more. We don’t know.

PiranhasPiranhas

Jackson’s Chameleon Jackson’s Chameleon

Brahminy “Hawaiian” Blind SnakeBrahminy “Hawaiian” Blind Snake

• Introduced 1930’s• Eats ants and beetles• Parthogenic• Not a threat

Introduced SpeciesIntroduced SpeciesAcanthophora, Eucheuma, & Gracillaria

Super Sucker to the Rescue!Super Sucker to the Rescue!

Mangroves in Hawaii (transplanted in 1902)

Brown Tree Snake, Guam

Upside-down JellyfishUpside-down Jellyfish

Snowflake CoralSnowflake Coral

Samoan CrabSamoan Crab

7 lbs 7 oz, 0/27/09 windward side

Blue stripped snapper

Forest Recovery

1903 = First forest reserve

Goal: water conservation

For the welfare and development of agriculture

Include all non-agricultural lands

1,057 plant species introduced

‘50s: Koa forests burned to plant alien pine trees

‘60s: Ohia forest defoliated by military

‘70s: Bulldozed ohia for alien tree plantations

‘80s: Burn ohia for “bio-power”

Forest Recovery

Volcanoes National Park

Created 1916; expanded 1927

Cattle grazing for 100 years

Cattle eat koa; park concerned

Complaints in ‘30s; no action

Grazing ended in 1938

Cattle out in 1940

WW II: Grazing again (‘42-’48)

Volcanoes National Park

1927: goat control started

5 years: 17,000 goats removed

1938: 5,000 goats removed

Goat proof fence: 70 sq. mi. area

25 years: 25,000 removed

Finally: Park is goat-free

Hawaii’s Extinction Crisis

Birds and PlantsBirds and Plants

Hawaii as % of US

land area 0.2%native species 14%endangered 28%extinct 73%

Human Impacts

4,000 - 6,000 alien plants

About 1,000 naturalized(reproducing naturally)

Introductions cause:

CompetitionHarbor diseasesDeplete resources

Factors Reducing Habitat

Crop lands

Cattle grazing

Feral animals (cattle, pigs, goats, sheep, deer)

Urbanization

1500 years ago1500 years ago

dry forestshrublandgrassland

dry forestshrublandgrassland

mesic forestshrubland

mesic forestshrubland wet forestwet forest

19911991

developed landsand non-nativevegetation

developed landsand non-nativevegetation

Solutions?• Conservation• Mechanical (physical removal)• Chemical (pesticides, herbicides)• Biological (natural predator)• Legislation• Education• Prevention• Ballast water:

* UV light* chemicals* dump water far from port

Conservation Protection

National Parks

Nature Conservancy Preserves

State Natural Areas Reserves

State Parks

Alien Animal Control

> $40,000/mile to fence

Haleakala NP = $5 million

Hard to eradicate animals

Animal control not popular

PETA: snares are “in-humane”

Few pigs survive > 24 hours

Pigs learn how to evade dogs and hunters

Hunting doesn’t always kill

Dog injury (prohibited?)

Pig Control: the Controversy

Lots of misinformation

Who speaks for the native vegetation, insects, birds?

Pig Control

Introduced grasses a problem

Fountain grass in Kona area

After fires, fire-adapted species become abundant

Helicopters = $700/hour

Fire

Fountain grassFountain grass

Introduces weeds

Clean boots before hiking

Activities breaking vegetation

Creates a path (water, erosion)

10-20 people/month= major disturbance

Human Activity

Specific diseases or pests for weeds

Lantana:

Introduced ~170 years ago

Mynah birds spread seeds

1900: was a major pest

22 insects introduced; 12 established

Biological Control

Lantana camara

Rigorous testing before introduction

No viruses; highly specific

1st on mainland; repeated here

Takes 7 to 8 years

Must learn to rear control

About 50% success

Biological Control

Biological Control

About $500,000/year

Hard to get $ for herbicides;easy for biological control

Public Attitudes

“Goat eradication program”

Negative public reaction

“Native ecosystem restoration program”

Positive public reaction

“Exotic”

“Alien”

Introduced SpeciesYellow ginger

1. What are the two ways in which plants and birds are able to travel the long-oceanic distance to the Hawaiian islands by drifting through the air?

2. How can plants and animals be dispersed to the Hawaiian islands by attachment to birds?

3. What accounts for the largest means of seed dispersal to the Hawaiian islands than any other mechanism?

4. What adaptations must a plant or seed have for dispersal by flotation in seawater?

5. What advantage does “rafting” play in dispersal?

Inquiry

6. Two of the major environmental factors influencing Hawai`i's habitat diversity are:

7. The most likely way that flowering plant species arrived in Hawai`i was by:

8. If a species is referred to as being endemic to Hawai`i, you can assume that it:

9. The main reason that Hawai`i's native species don't have thorns, stingers or chemical defenses is that they:

Inquiry

10. The removal of cattle from Oahu's forests was important to:

11. There are about _____ native flowering plant species in Hawai`i and _____ introduced ones that are now naturalized.

12. The control of pigs in Hawai`i's forests is: Biological control in Hawai`i has been:

Inquiry

Inquiry13. What class of vertebrates did not arrive to Hawaii

by natural means?14. Compare a generalist exotic species to a specialist.15. What 2 species have impacted the great lakes and

how did they arrive?16. Why are pigs such a problem?

Endemic, Native or Exotic?A B C D E

F G

Carnivorous caterpillar

Cane toadMushroom coralGreen turtle

Bottlenose dolphin

Blue stripped snapper