TROPICAL RAINFORESTSDefining Characteristics Agra, Joseph Yzrael Arsenio, Jesher Joshua
Introduction• Rain forests are called "cradles of diversity".• They spawn and support 50 percent of all living organisms on Earth even though they cover less than 5% of Earths surface.• A rainforests importance is truly incomprehensible when it comes to species diversity.
Introduction• Sunlight is a major limiting factor.• There is no annual rhythm to the forest; rather each species has to evolve its own flowering and fruiting seasons.• A variety of strategies have been successful in the struggle to reach light to adapt to the low intensity of light beneath the canopy.
Location• Tropical rainforests mainly occur inside the Worlds equatorial regions.• Tropical rainforests are restricted to the small land area between the latitudes 22.5° North and 22.5° South of the equator - between the Tropic of Capricorn and the Tropic of Cancer.
Location• The largest unbroken stretch of rainforest is found in the Amazon river basin of South America.• Over half of this forest lies in Brazil, which holds about one-third of the worlds remaining tropical rainforests.• Another 20% of the worlds remaining rainforest exists in Indonesia and Congo Basin, while the balance of the worlds rainforests are scattered around the globe in tropical regions.
Precipitation and Temperature• An important characteristic of tropical rainforests is moisture.• Tropical rainforests usually lie in tropical zones where solar energy produces frequent rainstorms.
Precipitation and Temperature• Rainforests are subject to heavy rainfall, at least 80", and in some areas over 430" of rain each year.• High volumes of rain in rainforests can cause local streams and creeks to rise 10-20 feet over the course of two hours.• Mean monthly temperatures are above 64 ° F;
Precipitation and Temperature• There is usually a brief season of reduced precipitation. In monsoonal areas, there is a real dry season, but that is more than compressed for with abundant precipitation the rest of the year.
Structure• Most of life in the tropical rainforest exists vertically in the trees, above the shaded forest floor - in the layers.• Each tropical rainforest canopy layer harbors its own unique plant and animal species interacting with the ecosystem around them.• The primary tropical rainforest is divided into at least five layers: the overstory, the true canopy, the understory, the shrub layer, and the forest floor.
Forest Floor• The area is mostly shade. Barely and direct light reaches this level, thus almost no plants grow in this area as a result.• Since hardly any sun reaches the forest floor things begin to decay quickly.• A leaf that might take one year to decompose in a regular climate will disappear in 6 weeks.• Giant anteaters live in this layer.
Understory Layer• Little sunshine reaches this area so the plants have to grow larger leaves to reach the sunlight.• The plants in this area seldom grow to 12 feet.• Many animals live here including jaguars, red-eyed tree frogs and leopards. There is a large concentration of insects here.
Canopy Layer• This is the primary layer of the forest and forms a roof over the two remaining layers.• Most canopy trees have smooth, oval leaves that come to a point. Its a maze of leaves and branches.• Many animals live in this area since food is abundant. Those animals include: snakes, toucans and treefrogs.
Emergent Layer• The tallest trees are the emergents, towering as much as 200 feet above the forest floor with trunks that measure up to 16 feet around.• Most of these trees are broad-leaved, hardwood evergreens. Sunlight is plentiful up here.• Animals found are eagles, monkeys, bats and butterflies.
Animal Adaptations• The tropical rainforest is a wet, warm forest of trees that grow very closely together. The canopy in the rainforest can release gallons of water each year into the atmosphere. The resulting moisture hangs over the forest, keeping the interior warm and humid. Animals living in the rainforest have had to adapt to these wet, warm conditions and have had to find niches that allow them to thrive. They do this by altering species characteristics to fit the tall trees, the constant humidity and the rainforest floor.
Animals in the canopy: Primates• Long arms to swing from tree to tree in the canopy, avoiding predators on the ground
The Aye-Aye• Nocturnal feeder, to avoid dangerous predators by day.• Large eyes allow more light in at night• Builds nests on top of trees in the canopy• Have a longer middle finger to reach within holes in tree trunks
Birds• Have large beaks to lose more heat. Birds in tropical regions can afford to have larger beaks than birds in temperate regions.• Differently sized beaks allow for different adaptations according to use
• Large beaks for cutting up pieces of fruit and nuts ▫ Toucan
• Hooked beaks to tear small prey apart ▫ Philippine Eagle
• Long thin beaks to reach within small holes on trees ▫ Black-cheeked Woodpecker
Farming• Leafcutter ants climb tall trees and cut small pieces of leaves which they carry back to their nest. The leaf pieces they carry are about 50 times their weight. The ants bury the leaf pieces, and the combination of the leaves and the ants saliva encourages the growth of a fungus, which is the only food these ants eat.
Predators• Camouflage allow predators to hunt undetected• They blend with the color of the leaves and trees
Bright Colors• Warn prospective predators to stay away from them ▫ Poison arrow frogs ▫ Native Central and South American tribes used to wipe the ends of their arrows onto the frogs skin to make their arrows deadly poisonous.
Plant Adaptations• Bark ▫ In drier, temperate deciduous forests a thick bark helps to limit moisture evaporation from the trees trunk. Since this is not a concern in the high humidity of tropical rainforests, most trees have a thin, smooth bark.
Lianas• Lianas are climbing woody vines that drape rainforest trees. They have adapted to life in the rainforest by having their roots in the ground and climbing high into the tree canopy to reach available sunlight. Many lianas start life in the rainforest canopy and send roots down to the ground.
Drip tips• The leaves of forest trees have adapted to cope with exceptionally high rainfall. Many tropical rainforest leaves have a drip tip. It is thought that these drip tips enable rain drops to run off quickly. Plants need to shed water to avoid growth of fungus and bacteria in the warm, wet tropical rainforest.
Buttresses• Many large trees have massive ridges near the base that can rise 30 feet high before blending into the trunk. Buttress roots provide extra stability, especially since roots of tropical rainforest trees are not typically as deep as those of trees in temperate zones.
Prop and stilt roots• Prop and stilt roots help give support and are characteristic of tropical palms growing in shallow, wet soils. Although the tree grows fairly slowly, these above-ground roots can grow 28 inches a month.
Epiphytes• Epiphytes are plants that live on the surface of other plants, especially the trunk and branches. They grow on trees to take advantage of the sunlight in the canopy. Most are orchids, bromeliads, ferns, and Philodendron relatives. Tiny plants called epiphylls, mostly mosses, liverworts and lichens, live on the surface of leaves.
Pitcher plants• Pitcher plant vines in the family Nepenthaceae have leaves that form a pitcher, complete with a lid. Sweet or foul-smelling nectar in the pitcher attracts insects, especially ants and flies, that lose their grip on the slick sides and fall into the liquid. Downward-pointing hairs inside the pitcher prevent the insects escape. The insects are digested by the plants and provide nutrients. Pitcher plants are not epiphytes but climbers rooted in the soil.
Abiotic Factors• Abiotic factors are those non-living, inert elements of an ecosystem that interact with the living components. The way that the abiotic factors interact with a particular ecosystem determines the types of plants and animals that can live in that ecosystem. The abiotic factors of the rainforest biome are the amount of water, sunlight, temperature and soil, and climate.
Water• The rainforest normally receives no less than 80 inches of rainfall annually. This is one of the most visible abiotic factors of the rain forest. The air under the canopy layer is still and very humid as a result. The trees also give off water through their leaves in a process called transpiration. This process can account for as much as half of the precipitation in a rain forest.
• Transpiration – loss of water vapor from parts of plants (leaves, stems, roots)
Sunlight• Light is the main source of energy in the rain forest. Plants use chlorophyll to change energy from sunlight into chemical energy through photosynthesis.
• In the rain forest, most of the sunlight is absorbed by the upper canopy, made up of trees between 60 and 100 feet tall.
• Only about 1 percent of the sunlight that strikes the top of the rain forest reaches to the forest floor. Plants are adapted to these conditions -- plants in the understory have large leaves to better absorb the weaker light, while those in the upper canopy have small leaves to reduce water loss in the strong sunlight.
Soil• The rain forest soil is shallow and thin, with few nutrients and soluble minerals. The heavy rains common in rain forests wash away the nutrients in the soil. As a result, the nutrients in a rain forest are largely found in the roots and leaves of living plants, and in the decomposing vegetation on the forest floor, rather than in the soil.
Temperature and Climate• The temperature in a rain forest rarely gets higher than 93 degrees F or drops below 68 degrees. The high and constant temperatures increase the rate of evaporation and keep humidity high. Warm temperatures also allow growth to occur quickly. As animal and insect life does not need to expend energy keeping warm, it can spend more energy on reproduction and reproduce with greater frequency. This explains some of the abundance of life in the rain forest.
• This temperature is attributed to the location of rainforests. They are near the equator, and so they receive a high amount of solar radiation.• Humid because of high amount of rainfall and solar energy.• Stays mostly the same all throughout the year.
HUMAN IMPACT• Several human activities have lead to the degredation of many tropical rainforest biomes.• These are mainly: ▫ Deforestation ▫ Overexploitation ▫ Introduction of Non-native Species
HUMAN IMPACTI. DEFORESTATION ▫ In general, deforestation, for whatever cause leads to habitat fragmentation and species displacement. ▫ This disrupts the forest ecosystem and might ultimately lead to a loss of biodiversity.
HUMAN IMPACTI. DEFORESTATION ▫ On a larger scale, this causes a reduction in the number of plant life that capable of converting carbon dioxide in the atmosphere into oxygen, thus contributing to global warming.
HUMAN IMPACTCAUSES OF DEFORESTATION ▫ Mining and Industry Mining and industrial development lead to direct forest loss due to the clearing of land to establish projects. Roads are constructed through previously inaccessible land, opening up and fragmenting the rainforest.
HUMAN IMPACTCAUSES OF DEFORESTATION ▫ Mining and Industry Severe water, air and land pollution occurs from mining and industry.
HUMAN IMPACTCAUSES OF DEFORESTATION ▫ Damming and Irrigation The construction of dams destroys the forest and often displaces organisms from their original habitat. The rates of waterborne diseases increase rapidly. Dams also trap silt, which may lead to coastal errosion.
HUMAN IMPACTCAUSES OF DEFORESTATION ▫ Damming and Irrigation The irrigation and industrial projects powered by dams leads to salination of soils and industry leads to pollution.
HUMAN IMPACTCAUSES OF DEFORESTATION ▫ Land Conversion Forests are cut down in order to make way for the conversion of forest land to agricultural areas, ranches, residential spaces or for other urban uses. Continual agricultural use often renders the soil extensively depleted which severely decreases the probability of recovery for these forests.
HUMAN IMPACTCAUSES OF DEFORESTATION ▫ Land Conversion Urbanization upstream from or near forests may introduce pollutants which would endanger and damage the forest ecosystem.
HUMAN IMPACTII. OVEREXPLOITATION ▫ Overexploitation of any resource, through whatever means, disrupts the balance of the forest ecosystem. ▫ Depending on what type of organisms are taken out, the ecological impact may vary (i.e. keystone vs dominant species).
HUMAN IMPACTREASONS FOR OVEREXPLOITATION ▫ Logging Large areas of rainforest are destroyed in order to make use of several trees selected for their timber. The heavy machinery used to penetrate the forests causes extensive damage. These may also be a source of pollution.
HUMAN IMPACTREASONS FOR OVEREXPLOITATION ▫ Tourism Rainforests are being threatened by excessive, poorly managed and loosely regulated tourism. Tourism is not inherently a detrimental, conversely tourism, specifically eco-tourism, serves a noble purpose of informing tourists of environmental issues and advocacies.
HUMAN IMPACTREASONS FOR OVEREXPLOITATION ▫ Tourism However, tourism is often used to make easy profit. Some forested areas are opened without prior enlistment of proper management strategies. If left as such, this may leave the rainforest exposed to physical pollutants (i.e. littering).
HUMAN IMPACTREASONS FOR OVEREXPLOITATION ▫ Tourism Infrastructure development and noise pollution may also disturb the inhabiting species and may disrupt the ecosystem. There is also a heightened risk of disease introduction.
HUMAN IMPACTREASONS FOR OVEREXPLOITATION ▫ Poaching and Hunting Causes a decline in tropical rainforest biodiversity. Some species are hunted merely for their fur, plumage or other parts while others are captured, shipped and sold as pets.
HUMAN IMPACTREASONS FOR OVEREXPLOITATION ▫ Poaching and Hunting This greatly disrupts the the forests ecosystems, often driving these species and several other species that are dependent on them to the brink of extinction.
HUMAN IMPACTII. INTRODUCTION OF INVASIVE SPECIES ▫ An invasive species is a species living outside its native distributional range, which has arrived there by human activity, either deliberate or accidental. ▫ Most introduced species are damaging to the ecosystem they are introduced into since they may invade ecological niches and thus may displace native species.
HUMAN IMPACTIII. INTRODUCTION OF INVASIVE SPECIES ▫ Only several introductions have resulted with no negative effects and even fewer have been proven to be, in fact, beneficial.
HUMAN IMPACTSUMMARY• Deforestation • Introduction of Invasive ▫ Mining and Industry Species ▫ Damming and Irrigation ▫ Land Conversion• Overexploitation ▫ Logging ▫ Tourism ▫ Poaching and Hunting