Download Tropical life zones

I. The tropics and diversity
II. Climate in the tropics
III. Holdridge life zones
IV. 7 representative sites
V. Other tropical ecosystems
Biogeography: the study of geographical distributions
of extinct and extant organisms, utilizing geological,
geographical, and biological sciences to explain
distribution patterns.
Estimates of Tropical Diversity
38,000 species
of vertebrates
300,000 species
of vascular plants
http://www.nhm.ac.uk/research-curation/projects/worldmap/index.html
Wilson, E.O. 1992.
The Diversity of Life.
Belknap Press,
Cambridge, Mass.
Leuhea seemanii (Tiliaceae)
•163 species of beetles
Erwin, T.L. 1982. Tropical forests: their richness in
Coleoptera and other arthropod species. The
Coleopterists’ Bulletin 36:74-75
163 species of beetles associated
with the canopy of 1 tree species
163 beetle species X 50,000 tropical tree species
= 8.2 million beetle species
Beetles represent about 40% of all arthropod species
 Number of arthropod species in the canopy = 20 million
Adding ground and understory arthropods
Total number of arthropod species =
30 million
May, R.M. 1986. How many species are there?
Nature 324:514-515.
Stork, N.E. 1993. How many species are there?
Biodiversity and Conservation 2:215-232.
Novotny et al. 2006. Science
Why Are There So Many Species of Herbivorous Insects
in Tropical Rainforests?
I. The tropics and diversity
II. Climate in the tropics
III. Holdridge life zones
IV. 7 representative sites
V. Other tropical ecosystems
Hurricane: air rises in a low-pressure area, cools, clouds
form, rain falls (cyclone), and the entire cyclone rotates
Hurricane: air rises in a low-pressure area, cools, clouds
form, rain falls (cyclone), and the entire cyclone rotates
El Nino, Southern Oscillation (ENSO): a recurring change
in atmospheric pressure between the east and west sides
of the Pacific (that results in a west-to-east flow of winds).
This oscillation causes a warm water current
that periodically flows southwards along the west coast
of South America.
ENSO is accompanied by large-scale changes in the normal
weather patterns in the Pacific as well as other parts of
the world.
(a) station name; (b) station altitude; (c) number of years of
observations (first figure: temperature; second figure: rainfall); (d)
mean annual temperature; (e) mean annual rainfall mm; (f) mean
daily minimum of coldest month; (g) lowest temperature
recorded; (h) mean daily maximum of warmest month; (i)
maximum temperature recorded; 0) mean daily temperature
range; (k) graph of monthly mean temperatures (scale divisions
are 10 °C); (I) graph of monthly mean rainfall (scale divisions are
20 mm); (m) drought period; (n) humid period; (0) monthly rainfall
greater than 100 mm (scale 1110 that of rainfall) (after Walter
1971).
Holdridge defined boundaries between
major vegetation units according to
1) logarithmic increases in mean annual
biotemperature; 2) logarithmic increases
in total annual precipitation, and 3) the
ratio of mean annual potential
evapotranspiration to mean total annual
precipitation.
I. The tropics and
diversity
II. Climate in the tropics
III. Holdridge life zones
IV. 7 representative sites
V. Other tropical
ecosystems
http://www.duke.edu/~manu/
La Selva Biological Station, Northeastern Costa Rica
Heredia Province, Costa Rica, located at 1025' N 8405' W
100 m elevation on the Caribbean slope.
1,536 hectares wet tropical forest
abuts Braulio Carrillo National Park at southern boundary
55% of La Selva primary forest
18% hi-graded primary and young secondary forest
1,600 angiosperms
multilayered community
Pentaclethra macroloba
(Leguminosae)
Figure 2. Average monthly
precipitation (mm) for the
three study sites. Mean
annual precipitation
1540mm for ACG,
2600mm for BCI, and
4200mm for LS.
o
Mean monthly maximum temperature ( C)
35
LS
BCI
GCA
30
25
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Barro Colorado Island (BCI), Central Panama
910’ N, 7951’ W, alt. 137m
1500 ha island in Lake Gatun in central Panama
operated by the Smithsonian Tropical Research Institute
in dry season, emergent canopy trees shed their leaves
most species are not deciduous
eastern part secondary forest from the 1880s
majority of the forest old growth at least 300 to 400 years old
about 1,100 angiosperms
DRY FOREST:
•12-30oC mean annual temp.
•.5-2m rainfall/year; prolonged dry season
•tropical broadleaf woodlands
•often merge with savannas
•canopy trees 20-30m tall
•spreading, flat-topped crowns
•understory trees 10-20m tall
•shrub layer 2-5m tall
•most endangered ecosystem?
Sector Santa Rosa, Area de Conservacion Guanacaste,
Northwestern Costa Rica
10º51' N, 85º37' W, 300 m
administrative center of 60,000 ha of tropical dry forest
Pacific coastal plain of northwestern Costa Rica
greater part of the Area de Conservacion Guanacaste (ACG)
forest a mosaic of 1-400 year-old succession and old-growth
approximately 800 species of angiosperms
SAVANNAS:
•grassland ecosystems; often very large
•associated with dry forests
•many dry forest tree and shrub species scattered throughout
•“climax” community
•maintained by climate, soils, fire, and human disturbance
Ficus thonningii (Fabaceae)
Themeda spp. (Poaceae)
Acacia tortilis (Fabaceae)
CLOUD FOREST:
•moisture from lowland forests rises and cools, creating mist
•found in at least 8 different life zones
•many ferns, mosses, epiphytes
•canopies typically 30-40m tall
•high levels of endemism
LOWER MONTANE MOIST FOREST:
•12-18oC mean annual temp.
•1-2m rainfall/year; variable dry season
•open evergreen forest
•canopy trees 30-35m tall
•oak communities are common
•understory trees 10-20m tall
•shrub layer 2-5m tall
PARAMO:
dominated by
shrubs and
Grasses .5 – 2 m
rain/year; 3 - 6 °C
mean ann. temp.
PUNA:
cold alpine grassland
dominated by grasses
some cacti or bromeliads
Phoenix sp.
(Arecaceae)
Welwitchsia
(Welwitschiaceae)
°C
50
40
30
20
MANGROVE:
•Plant community found in the saline, intertidal zone and the
constituent tree and shrub species that grow there. Water
temperature is greater than 24 C in the warmest month and rainfall
exceeds 1250 mm.
•Habitat: TIDAL FORESTS
•Plant: Any woody species that grows in tidal forests.
PNG has 12 ecoregions: four lowland and four montane broad leaf forests
one alpine scrub ecoregion along the central cordillera; a mangrove forest;
a freshwater swamp forest; and a savanna grassland;
all with distinct biotas and ecological conditions.
Line about 75% of tropical coasts
Consist of taxonomically unrelated plants
with unique adaptations
Eastern group – 40 species;
Western group – 8 species
Some ecosystem functions of
mangroves:
•source of endemism and contribute
to high B diversity
•prevent soil erosion
•act as a buffer against storms and
waves
•absorb pollutants
•prevent salt water intrusion
I. The tropics and diversity
II. Climate in the tropics
III. Holdridge life zones
IV. 7 representative sites
V. Other tropical ecosystems
RIVER ECOSYSTEMS:
•dominated by water
•provide varied habitats
•create riparian vegetation and gallery forests
•2400 species of fish in the Amazon
CANDIRU (Vandellia cirrhosa)
Paxton and Eschmeyer's
Encyclopedia of Fishes, 2nd edition (Academic Press)
In the early 1900s many strange and florid tales arose in that rich source of extravaganzas, the Amazon River Basin. One of the
strangest was the rumor of the existence of a fish that was urinophilic and could swim up the urethra or into the vagina of the
unwary native who urinated while bathing in the Amazon. It was said that this fish, known as candiru, was long, thin, and
capable of forcing its way into the body's passage-ways following the trail of urine. Once inside it would eat away the mucous
membranes and tissues until hemorrhage would kill it or the host. It was also said that even if one caught the fish by the tail,
once in the urethra it could not be pulled out because it would spread itself like an umbrella. Indeed, rumors had it that
penectomy was preferred to the misery and pain associated with leaving the fish in the urethra! Warthin refers to Professor
C.H. Eigenmann who first told him that natives of the Amazon wore coconut shells over their "organs" to prevent this parasite
from entering their bodies
FLOODS:
•dependent on local and regional precipitation
•disperse sediments
•fertilize floodplains
•enable aquatic organisms to utilize terrestrial ecosystems
•create temporary lakes and swamps
•“floodplain forest” occupies about 100,000 sq. km. in Amazon
Holdridge, L.R. 1967. Life zone ecology. Rev. Ed.
Jose: Tropical Science Center.
Janzen, D.H. 1988. Tropical dry forests. The most
endangered major tropical ecosystem. Pages 130137 in: E.O. Wilson (editor) Biodiversity. National
Academy Press, Harvard.