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Hawaiis Lecture Biodiversity
Environmental Diversity
Extremely wide range of habitats
temperature moisture soils vegetation
Environmental Diversity
Cold & Dry Cool & Dry Warm & Dry Warm & Wet Warm & Very Dry Hot & Very Dry Hot & Wet inversion trades
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
Questions: 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? How can plants and animals be dispersed to the Hawaiian islands by attachment to birds? What accounts for the largest means of seed dispersal to the Hawaiian islands than any other mechanism? What adaptations must a plant or seed have for dispersal by flotation in seawater? What advantage does rafting play in dispersal?
Long Distance Dispersal Wind, Water, & Wings Theory
The original colonist plants arrives in the following ways:
water wind birds
23% 2% 75%
Hawaiis Flowering Plants
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
galviewer galviewer
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.
galviewer galviewer
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.
pollinates
Yellow-faced bee Nesoprosopis
Flowering Plant Dispersal by Birds
migration migration
Birds
Travel through active flight such as migratory birds, marine birds, shore birds and waterfowl. Land birds underrepresented. Air currents are a major factor Northern Hemisphere jet stream.
Estimated 12.8% of the hypothetical original flowers arrived this way Attachment:
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. Fruit-eating birds ate the seeds, carried them internally, and excreted them on islands. Accounts for dispersal of an estimated 39% of the 255 hypothetical original plants.
Tetraplasandra flynii Has hairy gray fruits
Immigration Rates
number rate (1 every ) 272 110 thousand years 275 110 thousand years 25 1.2 million years 15 2 million years 1 30 million years
flowering plants insects land snails land birds mammals
Biodiversity
Number of species Native (got here naturally or evolved here) Endemic (found only here) Alien (exotic, human introduction)
NATIVE
Turkey fish
Occurring naturally in a given geographic area; not introduced as a consequence of human activities
ENDEMIC
Hawaiian Cleaner Wrasse
Occurring exclusively in a given geographic area, having originated in that area through natural means.
Hawaiian Honeycreepers
Hawaiian Crickets
Happyface Spiders
Tree Snails
Nene
Ohia Lehua
Hapu Ferns
Endemic and Native W ildlife of the Hawaiian Islands Estimated Percent Estimated No.in the % Endemism of Plant or Animal No. of Native Hawaiian Islands Endemic Group Colonists Species Species Marine Algae ? 420 13 Ferns & Fern Allies 114 145 70 Mosses Flowering Plants Terrestrial Mollusks Marine Mollusks Insects Mammals Birds 225 ca. 270 24 - 34 ? 230 - 255 2 ca. 25 233 ca. 1000 ca. 1000 ca. 1000 5,000 2 ca. 135 46 91 99 30 - 45 99 100 81
EXOTIC
Anemone fish
Introduced to a given geographic area as a consequence of human activities.
Speciation
new species
adaptive radiation
migrant species
9% of immigrants
Flowering Plants
Results of Speciation
colonists 270-280 233-254 23-24 15 species 956 3,722 1,064 70 radiation 91 81 294 42
flowering plants insects land snails land birds
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
Gaps in Speciation
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)
How they do arrive?
Dispersal Methods: Rafting Hitchhiking Currents Storms Migrating Islands
WHY SOME INTRODUCTIONS SUCCEED AND SOME DONT?
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
Pigs Dogs Taro Coconut Kukui Banana bread fruit Kava kudzu sweet potato yams
Ahupuaa
Ranges from the tip of the mtn to the reef area 1. Upland 2. Plains 3. Ocean
Slash & burn agriculture (swidden)
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
Mongoose
Brought in to help control rat population in sugar cane fields Rat nocturnal Mongoose diurnal Mongoose, dogs, and cats are the nenes main predator
Caribbean frog
coqui coqui
coqui
coqui
coqui coqui
coqui
Citric acid and caffeine
Feral pigs
Originally 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 dont know.
Jacksons Chameleon
Introduced Species
Acanthophora, Eucheuma, & Gracillaria
Mangroves in Hawaii (transplanted in 1902)
Brown Tree Snake, Guam
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
Forest Recovery
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
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
Hawaiis Extinction Crisis
Birds and Plants
Hawaii as % of US
land area native species endangered extinct
0.2% 14% 28% 73%
Human Impacts
4,000 - 6,000 alien plants About 1,000 naturalized (reproducing naturally) Introductions cause: Competition Harbor diseases Deplete resources
Factors Reducing Habitat
Crop lands Cattle grazing Feral animals (cattle, pigs, goats, sheep, deer) Urbanization
mesic forest shrubland
wet forest
dry forest shrubland grassland
1500 years ago
developed lands and non-native vegetation
1991
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
Pig Control: the Controversy
PETA: snares are in-humane Few pigs survive > 24 hours Pigs learn how to evade dogs and hunters Hunting doesnt always kill Dog injury (prohibited?)
Pig Control
Lots of misinformation Who speaks for the native vegetation, insects, birds?
Fire
Introduced grasses a problem Fountain grass in Kona area After fires, fire-adapted species become abundant Helicopters = $700/hour
Fountain grass
Human Activity
Introduces weeds Clean boots before hiking Activities breaking vegetation Creates a path (water, erosion) 10-20 people/month = major disturbance
Biological Control
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
Lantana camara
Biological Control
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
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
Yellow ginger
Introduced Species
Exotic Alien
Questions
Two of the major environmental factors influencing Hawai`i's habitat diversity are: The most likely way that flowering plant species arrived in Hawai`i was by: If a species is referred to as being endemic to Hawai`i, you can assume that it: The main reason that Hawai`i's native species don't have thorns, stingers or chemical defenses is that they:
The removal of cattle from Oahu's forests was important to: There are about _____ native flowering plant species in Hawai`i and _____ introduced ones that are now naturalized. The control of pigs in Hawai`i's forests is: Biological control in Hawai`i has been: