Tropical Deciduous Forests and Savannas

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Tropical Coastal Communities
Relationships to other tropical forest
systems — specialized swamp forests:
Mangrove and beach forests
Tropical Coastal Forests
Mangrove Forests
§  confined to tropical and subtropical
ocean tidal zones
§  confined to tropical and
subtropical zones at the interface
of terrestrial and saltwater
Mangrove Forests
§  stilt roots - support
§  water temperature must exceed 75°
F or 24° C in warmest month
§  unique adaptations to harsh
environment - convergent
Moluccas
Queensland, Australia
Venezuela
Rhizophora mangle - red mangrove
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Mangrove Forests
Mangrove Forests
§  stilt roots - support
§  stilt roots - support
§  pneumatophores - erect roots for
O2 exchange
§  pneumatophores - erect roots for
O2 exchange
§  salt glands - excretion
§  salt glands - excretion §  viviparous seedlings
Rhizophora mangle - red mangrove
Rhizophora mangle - red mangrove
Mangrove Forests
Mangrove Forests
§  80 species in 30 genera (20
families)
§  80 species in 30 genera (20
families)
§  60 species OW& 20 NW
§  60 species OW& 20 NW
(Rhizophoraceae - red mangrove most common in Neotropics)
Rhizophora mangle - red mangrove
Avicennia - black mangrove; inner
boundary of red mangrove, better
drained
Xylocarpus (Meliaceae) & Rhizophora
Xylocarpus (Meliaceae) & Rhizophora
Avicennia nitida (black mangrove,
Acanthaceae)
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Mangrove Forests
§  80 species in 30 genera (20
families)
Beach Forests
§  salt and sand - species often seen
in mangrove community
§  60 species OW& 20 NW
Four mangrove families in one
Neotropical mangrove
community
Avicennia Acanthanceae
Rhizophora Rhizophoraceae
Laguncularia Combretaceae
Maytenus Celastraceae
Hibiscus tiliaceus
Terminalia catappa
Cocos nucifera
Beach Forests
§  salt and sand - species often seen
in mangrove community
Beach Forests
§  woody climbers or runners
Hippomane (Euphorbiaceae)
- machaneel
Coccoloba uvifera
(Polygonaceae) seaside grape
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Beach Forests
§  woody climbers or runners
Beach Forests
§  woody climbers or runners
Scaevola
(Goodeniaceae)
Ipomoea pes-caprae
(Convolvulaceae) morning glory
Polihale State Park
western Kauai
Solanum (Solanaceae)
Chamaesyce
(Euphorbiaceae)
Tropical Deciduous Forests
or Rain/Summer Green Forests
Climate . . .
§  wet-dry seasonal alternation
Tropical Deciduous Forests
§  equatorial trough OR
subtropical high climate
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Tropical Deciduous Forests
Tropical Deciduous Forests
or Rain/Summer Green Forests
or Rain/Summer Green Forests
Climate . . . find this moving away from tropics
Climate . . . find this moving away from tropics
§  Gradient evident in
dry winter season from
tropics to subtropics
23No
§  Also found in
leeward sides of
mountains - west
Madagascar . . .
§  and monsoon climate
areas
0o
23So
Tropical Deciduous Forests
Tropical Deciduous Forests
or Rain/Summer Green Forests
or Rain/Summer Green Forests
Locations . . .
Locations . . .
§  South America - N
& S of Amazon,
Central America &
W. Indies
0o
§  W Africa & W Madagascar
§  Southern Africa
§  India, Indochina,
§  Australia
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Tropical Deciduous Forests
Tropical Deciduous Forests
Vegetation
Vegetation
§  Canopy closed in
wet summer, but
more open than
tropical rainforest
§  Forests closer to Tropics of
Cancer and Capricorn have
more pronounced dry winter
season - and more
pronounced deciduousness
§  Canopy opens up
in dry winter as some
or many deciduous
trees drop leaves adaptation to xeric
conditions
Santa Rosa, Costa Rica dry forest, summer
Alamos, Mexico (27o N)
Summer green, winter dry
Enterlobium (Fabaceae) canopy
Tropical Deciduous Forests
Tropical Deciduous Forests
Vegetation
Vegetation
§  Understory more developed
- better light
§  Green (photosynthetic)
stems common - no leaves
during winter
§  Flowering occurs at end of
dry season when leafless
Bursera Burseraceae,
Mexico
Hildegardia barteri Malvaceae, Africa
Ipomoea arborea
(Convolvulaceae - Mexico)
Ceiba acuminata
(Malvaceae - Mexico)
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Tropical Deciduous Forests
Tropical Deciduous Forests
Vegetation
Vegetation
§  Flowering occurs at end of
dry season when leafless
§  Flowering occurs at end of
dry season when leafless
Tabebuia (Bignoniaceae)
Tropical Deciduous Forests
Vegetation
Cochlospermum (Cochlospermaceae - Panama)
Tropical Deciduous Forests
Same vegetation - different flora
Flacourtia (Flacourtiaceae
Thailand)
§  Spines (anti-herbivory)
common on stems
Pachira - Malvaceae,
Mexico
Ceiba (kapokMalvaceae), Brazil
Acadia (Fabaceae,
Deckenia, palm
Mexico)
cabbage, Seychelles
Astrocaryum
(palm- Mexico)
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Tropical Deciduous Forests
Tropical Deciduous Forests
Vegetation
Vegetation
§  “Bottle” trees - water storage
§  “Bottle” trees - water storage: different genera in
different areas
Cola (silk
cotton tree,
Malvaceae),
Peru
Adansonia (Malvaceae)
Madagascar & Africa & Australia
Brachychiton
(Malvaceae,
Australia)
Tropical Deciduous Forests
Tropical Deciduous Forests
Vegetation
Vegetation
§  parasites common
§  epiphytes or lianas rare
Mistletoe (Loranthaceae-Venezuela)
Rhipsalis baccifera (Cactaceae
- Africa)
Mistletoe (Loranthaceae-Mexico)
Stemona (Stemonaceae Thailand)
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Thorn Forests/Scrub
§  Open forest with small deciduous trees or shrubs heavily
protected by thorns
Thorn Forests/Scrub
§  Location in subtropical latitudes between dry forests and
deserts . . . or on elevational gradient below tropical deciduous
forests
Thorn Forests/Scrub
§  Location in subtropical latitudes between dry forests and
deserts . . .
Thorn Forests/Scrub
§  Open forest with small deciduous trees or shrubs heavily
protected by thorns
§  Acacia - legume - worldwide
Acacia - spines for protection
also house ants that patrol plant
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Thorn Forests/Scrub
§  Open forest with small deciduous trees or shrubs heavily
protected by thorns
Euphorbia (Euphorbiaceae)
§  Floristic differences pronounced
Ethiopia
Thorn Forests/Scrub
§  Open forest with small deciduous trees or shrubs heavily
protected by thorns
§  Floristic differences pronounced
Cactaceae Mexico
Alluaudia and relatives (Didiereaceae) southern Madagascar
Senecio (Asteraceae)
Canary Islands
Thorn Forests/Scrub
§  Low scrub vegetation grading into deserts;
convergence of leafless, green-stemmed shrubs
with heavy spines
Opuntia (Cactaceae)
south Texas
Rutaceae, Mexico
Oleaceae, south Texas
Koeberlinia (Koberliniaceae) Mexico
Tropical Savanna Woodland
§  Tall grasslands with widely scattered trees and shrubs
§  Low to intermediate elevations where seasonal
drought and fire combine to favor perennial grasses
and limit tree growth
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Tropical Savanna Woodland
Tropical Savanna Woodland
§  Tall grasslands with widely scattered trees and shrubs
§  Tall grasslands with widely scattered trees and shrubs
§  Seasonal drought and fire combine to favor perennial
grasses and limit tree growth
§  Seasonal drought and fire combine to favor perennial
grasses and limit tree growth
Venezuelan llanos
Tropical Savanna Woodland
§  Termites and fire go together in savanna
biome
Tropical Savanna Woodland
§  Specialized soil types can produce tropical savannas
§  Calcium carbonate hardpan
Queensland, Australia
Venezuelan llanos
Serengeti hardpan with Acacia (Fabaceae)
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Tropical Savanna Woodland
Tropical Savanna Woodland
Vegetation:
§  small trees, crowns umbrella-like
Vegetation:
§  small trees, crowns umbrella-like
§  trunks thick and rough
§  trunks thick and rough
§  leaves xeromorphic or are shed in
dry season
§  leaves xeromorphic or are shed in
dry season
Byrsonima (Malpighiaceae), llanos
South African savanna leaf
convergence (white rhinoceros diet)
Tropical Savanna Woodland
§  xylopodia (“wooden feet”) in Brazilian cerrados
Tropical Savanna Woodland
§  xylopodia (“wooden feet”) in Madagascar
savanna
Asteraceae
– sunflower
family
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Specialized Tropical Savanna
Amazonian white sand savanna – nutrient poor:
Specialized Tropical Savanna
Amazonian white sand savanna - nutrient poor:
More genera of carnivorous
plants here than anywhere
else in the world!
Utricularia (bladderwort) - carnivorous
Brocchinia (Bromeliaceae) - some
carnivorous
Specialized Tropical Savanna
Amazonian laja - bare rock:
Venezuelan laja with burned Vellozia