The
Philippine
archipelago
is one of the world's great reservoirs of
biodiversity
and
endemism
. The archipelago includes over 7000 islands, and a total land area of 300,780 km
2
.
The Philippines was never connected to mainland
Asia
via
land bridges
,
[
dubious
–
discuss
]
so the flora and fauna of the islands had to cross ocean straits to reach the Philippines. The Philippines is part of the
Indomalayan realm
, and its flora and fauna is mostly derived from tropical Asia.
Botanically
, the Philippines are part of
Malesia
, a
floristic province
that includes the
Malay Peninsula
,
Indonesia
, and
New Guinea
. Most of the Malesian flora is derived from tropical Asia, including the
dipterocarps
, which are the characteristic tree of the Philippine forests. Elements of the
Antarctic flora
, which originated in the ancient
southern hemisphere
supercontinent of
Gondwana
, are also present, including ancient conifers like
podocarps
(
Podocarpus
,
Nageia
,
Sundacarpus
) and
araucarias
(
Agathis
).
The
ecoregions
of the Philippines are defined primarily by the sea levels during the Ice Ages, which were 120 meters lower than at present, as billions of gallons of water were locked away in huge continental ice sheets. This drop in sea level connected many presently separate islands into larger islands, which allowed for exchanges of flora and fauna:
- Greater Luzon
included
Luzon
,
Catanduanes
,
Marinduque
,
Polillo
, and several small islands.
- Greater Mindanao
included
Mindanao
,
Basilan
,
Bohol
,
Leyte
,
Samar
, and adjacent small islands.
- Greater Palawan
included
Palawan
, Balabac, Busuanga, Culion, Cuyo, and adjacent small islands.
- Greater Negros?Panay
included
Negros
,
Panay
,
Cebu
, and
Masbate
.
- Greater Sulu
included the most of the
Sulu Archipelago
, from
Tawi Tawi
to
Jolo
.
These formerly-linked islands each constitute a separate ecoregion, as does
Mindoro
, which remained separate from the rest, along with a few smaller islands, notably Camiguin, Sibuyan, and Siquijor.
Each group of islands that were linked by land bridges in the ice ages also constitutes a separate faunal region. The lack of a land bridge to the Asian continent prevented most of the Asian
megafauna
, including
elephants
,
rhinoceros
,
tapirs
,
tigers
,
leopards
, and
gibbons
, from reaching the Philippines, although they do inhabit the adjacent
Indonesian
islands of
Sundaland
, which were formerly linked to the Asian continent by lowered sea levels.
The other main factor that defines the Philippine ecoregions is elevation; the high
mountains of Luzon
and Mindanao host distinct montane rain forest ecoregions. The mountains of Luzon are also home to the
Luzon tropical pine forests
.
Terrestrial ecoregions
[
edit
]
by major habitat type
[1]
Tropical and subtropical moist broadleaf forests
Tropical and subtropical coniferous forests
Freshwater ecoregions
[
edit
]
Source:
[2]
- Northern Philippine Islands
- Palawan ? Busuanga ? Mindoro
- Mindanao
- Lake Lanao
Marine ecoregions
[
edit
]
by marine province
[3]
Central Indo-Pacific
[
edit
]
See also
[
edit
]
References
[
edit
]
- ^
Wikramanayake, Eric; Eric Dinerstein; Colby J. Loucks; et al. (2002).
Terrestrial Ecoregions of the Indo-Pacific: a Conservation Assessment.
Washington, DC: Island Press.
- ^
Spalding, Mark D., Helen E. Fox, Gerald R. Allen, Nick Davidson
et al.
"Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas".
Bioscience
Vol. 57 No. 7, July/August 2007, pp. 573?583.
- ^
Spalding, Mark D., Helen E. Fox, Gerald R. Allen, Nick Davidson
et al.
"Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas".
Bioscience
Vol. 57 No. 7, July/August 2007, pp. 573?583.
[1]
External links
[
edit
]