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Tropical Deciduous Forests and Savannas

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Tropical Deciduous Forests and Savannas 2/1/17 Tropical Coastal Communities Relationships to other tropical forest systems — specialized swamp forests: Tropical Coastal Forests Mangrove and beach forests § confined to tropical and & subtropical zones at the interface Tropical Deciduous Forests of terrestrial and saltwater Mangrove Forests Mangrove Forests § confined to tropical and subtropical § stilt roots - support ocean tidal zones § water temperature must exceed 75° F or 24° C in warmest month § unique adaptations to harsh Queensland, Australia environment - convergent Rhizophora mangle - red mangrove Moluccas Venezuela 1 2/1/17 Mangrove Forests Mangrove Forests § stilt roots - support § stilt roots - support § pneumatophores - erect roots for § pneumatophores - erect roots for O2 exchange O2 exchange § salt glands - excretion § salt glands - excretion § viviparous seedlings Rhizophora mangle - red mangrove Rhizophora mangle - red mangrove Xylocarpus (Meliaceae) & Rhizophora Mangrove Forests Mangrove Forests § 80 species in 30 genera (20 § 80 species in 30 genera (20 families) families) § 60 species OW& 20 NW § 60 species OW& 20 NW (Rhizophoraceae - red mangrove - Avicennia - black mangrove; inner Avicennia nitida (black mangrove, most common in Neotropics) boundary of red mangrove, better Acanthaceae) drained Rhizophora mangle - red mangrove Xylocarpus (Meliaceae) & Rhizophora 2 2/1/17 Mangrove Forests § 80 species in 30 genera (20 families) § 60 species OW& 20 NW Four mangrove families in one Neotropical mangrove community Avicennia - Rhizophora - Acanthanceae Rhizophoraceae Laguncularia - Maytenus - Combretaceae Celastraceae Beach Forests Beach Forests § salt and sand - species often seen § salt and sand - species often seen in mangrove community in mangrove community Hippomane (Euphorbiaceae) - machaneel Terminalia catappa Hibiscus tiliaceus Cocos nucifera 3 2/1/17 Beach Forests Beach Forests § woody climbers or runners § woody climbers or runners Ipomoea pes-caprae Coccoloba uvifera (Convolvulaceae) - (Polygonaceae) - morning glory Polihale State Park seaside grape western Kauai Beach Forests § woody climbers or runners Tropical Deciduous Forests Scaevola (Goodeniaceae) Solanum (Solanaceae) Chamaesyce (Euphorbiaceae) 4 2/1/17 Tropical Deciduous Forests Tropical Deciduous Forests or Rain/Summer Green Forests or Rain/Summer Green Forests Climate . Climate . find this moving away from tropics § wet-dry seasonal alternation § equatorial trough OR 23No subtropical high climate 0o 23So Tropical Deciduous Forests Tropical Deciduous Forests or Rain/Summer Green Forests or Rain/Summer Green Forests Climate . find this moving away from tropics Locations . § Gradient evident in dry winter season from § South America - N tropics to subtropics & S of Amazon, Central America & § Also found in W. Indies leeward sides of 0o mountains - west Madagascar . § and monsoon climate areas 5 2/1/17 Tropical Deciduous Forests Tropical Deciduous Forests or Rain/Summer Green Forests Vegetation Locations . § Canopy closed in § W Africa & W Madagascar § India, Indochina, wet summer, but § Southern Africa § Australia more open than tropical rainforest Santa Rosa, Costa Rica dry forest, summer § Canopy opens up in dry winter as some or many deciduous trees drop leaves - adaptation to xeric conditions . and winter Tropical Deciduous Forests Tropical Deciduous Forests Vegetation Vegetation § Canopy closed in § Forests closer to Tropics of wet summer, but Cancer and Capricorn have more open than more pronounced dry winter tropical rainforest season - and more pronounced deciduousness Santa Rosa, Costa Rica dry forest, summer § Canopy often has same families or Alamos, Mexico (27o N) genera of evergreen Summer green, winter dry tropical forests – but different species Enterlobium (Fabaceae) canopy 6 2/1/17 Tropical Deciduous Forests Tropical Deciduous Forests Vegetation Vegetation § Understory more developed § Flowering occurs at end of - better light dry season when leafless § Green (photosynthetic) stems common - no leaves during winter Bursera - Burseraceae, Mexico Hildegardia barteri - Ipomoea arborea Malvaceae, Africa (Convolvulaceae - Mexico) Tropical Deciduous Forests Tropical Deciduous Forests Vegetation Vegetation § Flowering occurs at end of § Flowering occurs at end of dry season when leafless dry season when leafless Tabebuia (Bignoniaceae) Cochlospermum (Cochlospermaceae - Panama) 7 2/1/17 Tropical Deciduous Forests Tropical Deciduous Forests Vegetation Same vegetation - different flora § Spines (anti-herbivory) Flacourtia (Flacourtiaceae common on stems Thailand) Pachira - Malvaceae, Mexico Ceiba (kapok- Malvaceae), Brazil Acacia (Fabaceae, Deckenia, palm Astrocaryum Mexico) cabbage, Seychelles (palm- Mexico) Tropical Deciduous Forests Tropical Deciduous Forests Vegetation Vegetation § “Bottle” trees - water storage § “Bottle” trees - water storage: different genera in different areas Adansonia (Malvaceae) Cola (silk Madagascar & Africa & Australia cotton tree, Malvaceae), Peru Brachychiton (Malvaceae, Australia) 8 2/1/17 Tropical Deciduous Forests Tropical Deciduous Forests Vegetation Vegetation § parasites common § epiphytes or lianas rare Mistletoe (Loranthaceae-Venezuela) Rhipsalis baccifera (Cactaceae - Africa) Stemona (Stemonaceae - Mistletoe (Loranthaceae-Mexico) Thailand) Thorn Forests/Scrub Thorn Forests/Scrub § Open forest with small deciduous trees or shrubs heavily § Location in subtropical latitudes between dry forests and deserts protected by thorns . 9 2/1/17 Thorn Forests/Scrub Thorn Forests/Scrub § Location in subtropical latitudes between dry forests and deserts § Open forest with small deciduous trees or shrubs heavily . or on elevational gradient below tropical deciduous forests protected by thorns § Acacia - legume - worldwide Acacia - spines for protection also house ants that patrol plant Thorn Forests/Scrub Thorn Forests/Scrub § Open forest with small deciduous trees or shrubs heavily § Open forest with small deciduous trees or shrubs heavily protected by thorns Euphorbia (Euphorbiaceae) protected by thorns § Floristic differences pronounced Ethiopia § Floristic differences pronounced Cactaceae Mexico Alluaudia and relatives (Didiereaceae) southern Madagascar Senecio (Asteraceae) Canary Islands 10 2/1/17 Thorn Forests/Scrub Tropical Savanna Woodland § Low scrub vegetation grading into deserts; § Tall grasslands with widely scattered trees and shrubs convergence of leafless, green-stemmed shrubs § Low to intermediate elevations where seasonal with heavy spines drought and fire combine to favor perennial grasses and limit tree growth Opuntia (Cactaceae) south Texas Rutaceae, Mexico Oleaceae, south Texas Koeberlinia (Koberliniaceae) Mexico 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 § Seasonal drought and fire combine to favor perennial grasses and limit tree growth grasses and limit tree growth Venezuelan llanos 11 2/1/17 Tropical Savanna Woodland Tropical Savanna Woodland § Tall grasslands with widely scattered trees and shrubs § Termites and fire go together in savanna biome § Seasonal drought and fire combine to favor perennial grasses and limit tree growth Queensland, Australia Venezuelan llanos Venezuelan llanos Tropical Savanna Woodland Tropical Savanna Woodland § Specialized soil types can produce tropical savannas Vegetation: § Calcium carbonate hardpan § small trees, crowns umbrella-like § trunks thick and rough § leaves xeromorphic or are shed in dry season Serengeti hardpan with Acacia (Fabaceae) Byrsonima (Malpighiaceae), llanos 12 2/1/17 Tropical Savanna Woodland Tropical Savanna Woodland Vegetation: § xylopodia (“wooden feet”) in Brazilian cerrados § small trees, crowns umbrella-like § trunks thick and rough § leaves xeromorphic or are shed in dry season South African savanna leaf convergence (white rhinoceros diet) Tropical Savanna Woodland Tropical “Dry Forest” Flora & Fauna Relationships § xylopodia (“wooden feet”) in Madagascar savanna PNAS 2009 • When did the Cerrado originate? • Did the Cerrado species come in via dispersal of dry adapted species? (niche conservatism) • Did the Cerrado species arise in “Dufflepuds” – Voyage of situ from surrounding wet adapted the Dawn Treader tropical forest species? (adaptive radiation) Asteraceae – sunflower family 13 2/1/17 Tropical “Dry Forest” Flora & Fauna Relationships • Cerrado species arose in last § red-fronted brown lemur in Madagascar dry 10my forests – nocturnal & derived from wet tropical • All arose in situ from forest lemur lineages surrounding wet adapted species • Convergent evolution for arid, § nocturnal & small fire system in many groups! rodents elsewhere — adaptive radiations! § lizards account for up to 40% species in Neotropical dry forest fauna - Anolis § Myrmicinae ant radiations (Atta) Tropical “Dry Forest” Flora & Fauna Relationships Tropical “Dry Forest” Flora & Fauna Relationships § cat evolution more complicated § cat species are well adapted to both tropical dry forests (and temperate) but § biogeography? also to tropical wet forests § tropical wet or dry origin? §National Geographic – Feb 2017 14.
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