Seeing Is Believing

the rainforest canopy north of Manaus, BrazilGo back to Google Earth. Fly to Iquitos, Peru.  Zoom in until you can find the markers for notable places in the city. (You simply move your cursor over them to see labels.)

Zoom in as close as you can until you begin to lose resolution. What can you see? How can you characterize the terrain? What conclusions can you draw from the air? How much of the area is cleared? How much seems undisturbed? Use the scale to determine the largest expanses that appear to be undisturbed. Do the edges of areas near clearings look any different than the centers of uncleared forests?

Compare the various branches of the river. Can you see the junction of the muddy Amazon with less turbid streams? Where does the mud come from? Does this have significance for the ecosystem? Does it provide any clues about the

Zoom down on a heavily wooded area. Can you see differences in the treetops? Could you make any inferences about the number of species from the air?

Then move north of the city, and east, following the river until you find Ceiba Tops Lodge. Look at roads and rivers.

Ecologists often must study rainforests from the top. Thatís because the understory (the bottom stratum of the forest)is almost always too densely foliated to travel through. Remember the competition.  Some types of satellite images can actually see through foliage to find relics and other ground objects, but thatís still difficult in such dense forests. What deductions can you make from your satellite-eye view?

Like every scientific exploration, this one is bound to raise more questions than it answers. What questions do you now have, that you want to answer when you arrive?

Photo credit: NASA (Brazilian Rainforest)


 

Closer Connections

Google Earth canít take you any closer. But if it could, hereís just a little of what you would see, beginning with the plants.

Evergreen plants: Trees that never lose all of their leaves at one time. (Evergreens in the temperate zones almost all have needles. But there are many broad leaved evergreens in the tropical rain forest.)

Vines/Lianas: Since every rainforest plant must compete for light, itís always an advantage to use a tall friend. Over 90% of known species of climbing plants occur in tropical rain forests. Using another plant for support saves energy and provides a competitive advantage, as long as the hitch-hiker doesnít get too heavy or successful.  The Philodendron that you see at many restaurants as an ornamental plant is an important rainforest plant, on the border between a commensal and a parasite. (Remember; we make the categories--the plants just survive.) The vine climbs a tree for light, then sends long roots back down to the ground as an aqueduct to bring water and minerals back up for itself and all the other plants at the top of the canopy.

Epiphytes: These are plants that grow entirely on another plant (unlike vines which are rooted in the ground.) There are 25,000 species of epiphytes in the tropical rainforests of the world. Epiphytes are challenged to get water and must tolerate the shade of their supportive partners.

Flowers: Likely to be bright and gaudy, with colors and odors to attract. Red flowers are likely to attract hummingbirds. Bees prefer yellows, blues, and whites; beetles prefer creams or greenish colors; flies prefer browns, purples, or greens; moths prefer reds, purples, whites, and pale pinks; butterflies prefer bright reds and purples. Insects can also see ultraviolet ("black") light.

Leaves of rainforest plants are likely to be simple (one main frond without lobes) with entire (smooth) margins. Youíll remember that prominent veins are often a sign of C4 photosynthesis, an adaptation to high light, carbon dioxide and water. Drip tips (pointed ends) help water drain from these leaves. Too much water would encourage the growth of symbiotic algae and fungi. When a symbiont becomes too thick it becomes a parasite, damaging leafís ability to gather light or destroying its epidermis.

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Photo notes: (Clockwise) mangroves with lianas; heavy veins indicating Krantz anatomy; orchids flamboyantly attracting pollenators.