Biology Reference
In-Depth Information
Figure 2.24
Mangrove formation (manglar) of
Rhizophora mangle
along bay near UNAM's
tropical biological station, Catemaco, Veracruz, Mexico.
Eichornia crassipes
, water hyacinth, with
Lemna
, duckweed; fi g. 2.25), the
lowland neotropical rain forest (southern Veracruz State; fi g. 2.26), and
the lower to upper montane broad-leaved forest. Within the latter, on the
eastern slopes of the Sierra Madre Oriental, in an altitudinal zone between
1000 and 2000 m, there is a deciduous forest association (a formation in
eastern North America) of
Acer
,
Alnus
(alder),
Cornus
(dogwood),
Fa g us
,
Juglans
,
Liquidambar
(sweetgum),
Magnolia
,
Platanus
(sycamore),
Populus
,
Quercus
,
Salix
(willow), and
Ulmus
(elm). Another association, included
within the coniferous forest formation or within the deciduous forest for-
mation, is the midaltitude
Pinus
-
Quercus
(pine-oak) forest. This is the most
widespread vegetation type in Mexico, and it covers about 14 percent of the
landscape. The deciduous forest grades upward into a zone of fog, and the
vegetation is called the cloud forest association. Farther up, there are cold
winds and shorter trees, often with twisted trunks covered with lichens,
ferns, and mosses. This is the elfi n forest association. Both are found in the
Sierra Madre Oriental, the Transvolcanic Belt, and the southern states of
Oaxaca and Chiapas. On the highest peaks of the Transvolcanic Belt there
is a limited treeless vegetation of alpine tundra, or páramo. Of the twelve
vegetation types recognized here for the New World, eleven (all but the
lowland tundra) are found in Mexico.
