Transcript Dry and Wet Forests

Wet and dry forests of Hawaii
Copyright, 1996 © Dale Carnegie & Associates, Inc.
Questions
• Why are there both wet and dry forests in
Hawaii?
• What is the weather pattern like?
• How much annual rainfall do they receive
in the Hawaiian wet and dry forests?
Questions
• Does the flora change as elevation
changes?
• What types of plants grow in the wet
forests?
• What kinds of plants grow in the dry
forests?
Weather patterns
• Trade winds
• Rainy season
– October-March
• Dry season
– April-September
Weather patterns
• Windward
– Wet forests
• Leeward
– Mesic forests
• 2,000-4,000 ft.
– Dry forests
• Below 2,000 ft.
Weather Patterns
• Annual rainfall
– Rainforests
• Up to 450”
– Dry forests
• As little as 5”
Hawaiian Flora
• 970 species of native plants
• Introduced species
Hawaiian Flora
• 91% endemic
– Species which grow only on the Hawaiian
islands
• Evolve quickly
• Specialized
• Limited range
Hawaiian Flora
• 9% indigenous
– Species also grow in other places
Wet Forests
Wet Forests
• Bryophytes
• Epiphytes
• Ferns
• Shrubs
• Trees
Pepperomia
• Herbaceous epiphyte
• Common
• Many different species
Pepperomia
hawaiiensis
oahuensis
Wet Forests • Clermontia
– Lobelioid
– Epiphytic shrubs or small trees
– Found in clearings in wet forests
Clermontia
montis loa
hawaiiensis
Dubautia
• Asteraceae
• Member of the Silversword alliance
• Shrub or small tree
• Found on Kawai
Dubautia knudseni
Viola chamissoniana ssp.
robusta
• Wet forest violet
• Can be epiphytic
Viola chamissioniana robusta
Wet Forests - Ferns
• Dicranopteris
• Sadelaria
• Cibotium
Dicranopteris
Sadelaria
Cibotium
Wet Forests - Shrubs
• Gouldia terminalis
– Common in wet forests
– May look very different in different
environments
Gouldia terminalis
Wet Forests -Trees
• Metrosideros polymorpha
– Abundant in the wet forests
– Also can be found in dry forests
Metrosideros polymorpha
Wet Forests - Trees
• Pritchardia
– Only native palm
– Large seeds
• Adaptation for growing in shade
Pritchardia
beccariana
Dry Forests
Dry Forests - Shrubs
• Viola chamissioniana
• Found in Koa forests
– Up to 8’ tall
Viola
chamissioniana
ssp. tracheliifolia
Dry forests - Trees
• Acacia koa
– Timber trees
– Found on every island
– 2,000-4,000 ft- mesic forest
Acacia koa
Wilkesia
• Silversword alliance
• Neither common nor rare
• Dry to mesic forests on Kawai
Wilkesia gymnoxiphium
Dry forests - Trees
• Erythrina sandwicensis
– Semi deciduous during dry season
– Seeds take 1-2 years to germinate
Erythrina sandwicensis
Dry Forests - Trees
• Cyanea leptostegia
– Kokee, Kauai
– Lobeleoid, to 40’ tall
– Grows in Koa froests
• Herbaceous plants
Cyanea leptostegia
Endangered Forests
• 40% of Hawaiian wet forests have been
destroyed
• 90% of the original dry forests are gone
Endangered Dry Forests
• Kokia cookei
– Only one left
– Waimea Park
Kokia cookei
Hibiscadelphus
• Very rare native genus
• Hibiscadelphus hualalaiensis only one
plant in the wild
Hibiscadelphus hualalaiensis
Endangered Forests
• The dry forest habitat used to hold the
highest diversity
• Wet forests now have highest diversity
Endangered Forests
• Polynesians and Europeans
– Introduced plants
• Fountain grass- Pennesitum
• Molasses grass- Melinis
• Lantana
• Weeds
Invasive plants
Endangered Forests
– Introduced Animals
• Goats
• Pigs
• Rats and mice
– Habitat destruction
– Dispersal
Endangered Forests
– Cleared forests
• Fire
• Grazing
• Development
• Recreation
Endangered Forests
• Introduction of non native species
• Loss of speciation
• Loss of diversity
• Loss of ecosystem
Questions
• Why are there both wet and dry forests in
Hawaii?
• What is the weather pattern like?
• How much annual rainfall do they receive
in the Hawaiian wet and dry forests?
Questions
• Does the flora change as elevation
changes?
• What types of plants grow in the wet
forests?
• What kinds of plants grow in the dry
forests?
References
• Allen, William. Environment Hawai`i, Volume 11 Number 3
(September 2000). http://planet-hawaii.com/environment/900at.htm
• Cronquist, Sherwin. Hawaii, A Natural History.1980. Honolulu, SB
Printers Inc.
• Gon, S. and D. Olson. World Wildlife Fund website. 2001.
http://www.worldwildlife.org/wildworld/profiles
Refrences
• Wilson, Kenneth. Natural History Museum of Los Angeles
County web site.
http://www.nhm.org/research/botany/Hawaii_Vanishing_Flora/index
.html
• Carr, Gerald. University of Hawaii website. 2003.
http://www.botany.hawaii.edu.