1. What is a 'rainforest?'
The rainforest is one of the world's most diverse biomes. Covering only 7% of the world's surface, the rainforest contains about half of the plants and animals on Earth. Even today, around 5-30 million species in the tropical rainforest have not yet been described or classified. In addition, the tropical rainforest contains about 20-86 different kinds of plants and shrubs.
Due to the 'vertical layering' of vegetation, called 'canopies,' rainforest habitats are home to a variety of different species. This layering allows the development of microclimates, or small specialized climates where organisms can thrive independently such as on the inside of a log. "Microclimate is the suite of climatic conditions measured in localized areas near the earth's surface." (Geiger 1965) hese layers are also characterized by the types of animals that live inside in them; the understory layer, for example, has a large population of red-eyed tree frogs because it is generally where there are higher populations of other insects due to the lack of sunlight and broad-leafed plants.
Image Source: blog.growingwithscience.com
Due to the 'vertical layering' of vegetation, called 'canopies,' rainforest habitats are home to a variety of different species. This layering allows the development of microclimates, or small specialized climates where organisms can thrive independently such as on the inside of a log. "Microclimate is the suite of climatic conditions measured in localized areas near the earth's surface." (Geiger 1965) hese layers are also characterized by the types of animals that live inside in them; the understory layer, for example, has a large population of red-eyed tree frogs because it is generally where there are higher populations of other insects due to the lack of sunlight and broad-leafed plants.
Image Source: blog.growingwithscience.com
2. Where are rainforests located?
Our planet can generally be divided into two parts: the living and non-living, or biotic and abiotic factors. Nature is therefore the cause of interaction between the biotic and abiotic factors on Earth. Biotic factors in a rainforest biome include plants, animals, insects, and anything living while the abiotic factors would be the air, sunlight, wind, soil, and temperature. The most important of these biotic factors in determining a type of biome would be the type of vegetation and 'community structure.' This means that each biome is defined by the kind of plants it contains and how the precipitation (average rain levels) and how they are formed in relation to other defining characteristics, temperature and moisture.
The tropical rainforest climates are found in areas such as Central America, South America, Africa, southeastern Asia. and Australia. Countries containing rainforests are located in an area between 15-25 degrees North and South of the equator (G. Michael, 2001), called the tropics.
Image Sources (Left to Right): http://upload.wikimedia.org/ - http://kids.mongabay.com
The tropical rainforest climates are found in areas such as Central America, South America, Africa, southeastern Asia. and Australia. Countries containing rainforests are located in an area between 15-25 degrees North and South of the equator (G. Michael, 2001), called the tropics.
Image Sources (Left to Right): http://upload.wikimedia.org/ - http://kids.mongabay.com
3. Why are rainforests known as the "lungs of the Earth?"
The largest concentration of rainforest in the world is located in a region called the Amazonian Rainforest, located around the Amazon River. Stretching over seven million square kilometers and seven countries, the Amazonian Rainforest creates about 20% of the oxygen on Earth due to its dense population of trees. Through photosynthesis, the process in which plants use carbon dioxide into oxygen and energy in the presence of sunlight, this region supports a large part of the world's ability to create oxygen and support the organisms that live on Earth.
Image Source: Conservation.org
Image Source: Conservation.org
4.What is the climate like in the rainforest?
Climate in the tropical rainforest climate is true to its name; with an average of about 200 cm of rain per year, the tropical rainforest biome is characterized by its high humidity and vegetation. As mentioned before, the tropical rainforest regions exist in the tropics - close to the equator - where it is usually warm and results in high humidity. Animals in the rainforest have adapted to the high water content in the air and constant rain and have adapted either physically or behaviorally as a result. The rainforest's warm climate and high humidity are able to sustain and house its incredible biodiversity and wildlife.
5. What are the kinds of wildlife that exist in the rainforest?
Tropical rainforests are the home of a diverse range of animals, big and small. Between its diverse flora and fauna, this biome was one of the highest amounts of biodiversity in the world. In addition, there are some 20 - 86 species of plants and about 5 - 30 million animals that have not yet been classified. Here are some of the animals present in the tropical rainforest regions.
6. What distinguishes the tropical rainforest from a tropical dry forest?
Above all, these two types of forests are distinguished by their average precipitation per year, amount of biodiversity, and vegetation. They are both referred to as tropical due to their position in relation to the equator; tropical rainforests located between 15-20 degrees north and south of the equator, tropical dry forests located either within these coordinates or a few degrees above and below the tropical region.
Tropical dry forests receive about the same amount of rainfall as tropical rainforests, but have a dry season - often called a 'drought' - depending on the location of the area. During this season, deciduous trees often lose their leaves to conserve water. Likewise, the animals living in tropical dry forests have become adapted to the annual dry season and have learned to conserve water and energy during this season to keep from starving.
Although most of the tropical dry forests consist of deciduous vegetation, they also have evergreen trees which are impervious to this dry season and keep their leaves year-round. Such trees feed off of deep groundwater deposits and have small, needle-like leaves to limit water loss through transpiration.
Tropical dry forests receive about the same amount of rainfall as tropical rainforests, but have a dry season - often called a 'drought' - depending on the location of the area. During this season, deciduous trees often lose their leaves to conserve water. Likewise, the animals living in tropical dry forests have become adapted to the annual dry season and have learned to conserve water and energy during this season to keep from starving.
Although most of the tropical dry forests consist of deciduous vegetation, they also have evergreen trees which are impervious to this dry season and keep their leaves year-round. Such trees feed off of deep groundwater deposits and have small, needle-like leaves to limit water loss through transpiration.
7. What kinds of predator-prey relationships are found in a tropical rainforest?
Predation is a natural process which occurs within every biome, both big and small. Resulting in limiting of the biotic features of the ecosystems, predation comes in several forms that can be found in the rainforest biomes and beyond. Predatory relationships can range from negative to positive to neutral. Parasitism is the negative interaction by which one organism thrives and the other is harmed as a result, and the organism that is harmed is called the host. Symbiosis is the neutral interaction in which both of the organisms live in close proximity with one another. Finally, a mutualistic relationship is a positive relationship in which both organisms benefit as a result of living together.
Parasitism - Rafflesia arnoldii and Tetrastigma Plants
The Rafflesia arnoldii, also known as the 'corpse flower' for its awful smell, is considered to be the parasite of its host plant, the Tetrastigma (from the grape family). The Rafflesia flower is not visible until the final stages of its growth in which it buds into a large, red flower. Until then, the plant is stuck to a Tetrastigma vine where it receives protection and nutrition, although it slowly kills the vine as the flower grows.
Symbiosis - Ants and Macaranga Trees
In the Southeast Asian rainforests, ant and the Macaranga trees exist in harmony with one another by helping each other survive. While the trees provide food and shelter for the ants, the ants repel any other insect predators and keep other climbing plants such as vines from growing on the trees.
Mutualism - Termite and Protozoa
Protozoa, a type of prokaryote, exist in the stomach of the termites and help the termites digest cellulose from the wood that they eat. As a result, the termite allows the protozoa to live inside of it and receives food, shelter, and transport.
Predation Limiting Growth
Above all, predation can also be a contributing factor of population control which keeps the ecosystem running smoothly. Population can be limited by density-dependent and density-independent factors as a result of predation. Density-dependent factors, such as competition, predation, parasitism and disease, are dependent on the size of a population; density independent factors also affect populations but occur regardless of how big or small a population is. Independent factors include weather, natural disaster, seasons, and human activities.
Examples of Limiting Population Through Predation
Seed predation - Mammals of varying size in the rainforest ecosystem regulate tree populations by consuming and defecating the seeds into certain areas. As a result, the trees are limited by the population of mammals in that region and their dietary habits.
Parasitism - Rafflesia arnoldii and Tetrastigma Plants
The Rafflesia arnoldii, also known as the 'corpse flower' for its awful smell, is considered to be the parasite of its host plant, the Tetrastigma (from the grape family). The Rafflesia flower is not visible until the final stages of its growth in which it buds into a large, red flower. Until then, the plant is stuck to a Tetrastigma vine where it receives protection and nutrition, although it slowly kills the vine as the flower grows.
Symbiosis - Ants and Macaranga Trees
In the Southeast Asian rainforests, ant and the Macaranga trees exist in harmony with one another by helping each other survive. While the trees provide food and shelter for the ants, the ants repel any other insect predators and keep other climbing plants such as vines from growing on the trees.
Mutualism - Termite and Protozoa
Protozoa, a type of prokaryote, exist in the stomach of the termites and help the termites digest cellulose from the wood that they eat. As a result, the termite allows the protozoa to live inside of it and receives food, shelter, and transport.
Predation Limiting Growth
Above all, predation can also be a contributing factor of population control which keeps the ecosystem running smoothly. Population can be limited by density-dependent and density-independent factors as a result of predation. Density-dependent factors, such as competition, predation, parasitism and disease, are dependent on the size of a population; density independent factors also affect populations but occur regardless of how big or small a population is. Independent factors include weather, natural disaster, seasons, and human activities.
Examples of Limiting Population Through Predation
Seed predation - Mammals of varying size in the rainforest ecosystem regulate tree populations by consuming and defecating the seeds into certain areas. As a result, the trees are limited by the population of mammals in that region and their dietary habits.
The graph on the left shows the usual trend of predator-prey relationships and regulation. Another two organisms in the rainforest that could be applied to this graph would be the the Brazilian Nut Tree and the toucan (as shown in the food web). Without the toucan, the Brazilian Nut Tree would grow without limits and take resources such as water and living space away from other plant species. With the help of the toucan, this tree population is able to grow at a regulated pace but without harming other organisms.
8. What are some of the issues the rainforest biome is suffering from today?
In a world that is rapidly growing both in population and industry, the tropical rainforest is among one of the world biomes that is suffering the most from this development. According to ecology specialist and professor Richard B. Primack, “Rainforests are threatened throughout the tropics by human activiities, but the intensity of each threat varies by region” (Primack, page 444).
According to Primack, the tropical rainforests have been most affected by human activities in the tropical regions by logging (both domestic and international trade markets), hunting, fires, deforestation, and invasive species. Although each phenomena works mostly independent of the other, they all occur at varying rates and numbers according to the kinds of markets and needs of a certain country or group of people.
To contact Richard Primack, the ecological expert behind the information on negative human impact on rainforests, email [email protected].
According to Primack, the tropical rainforests have been most affected by human activities in the tropical regions by logging (both domestic and international trade markets), hunting, fires, deforestation, and invasive species. Although each phenomena works mostly independent of the other, they all occur at varying rates and numbers according to the kinds of markets and needs of a certain country or group of people.
To contact Richard Primack, the ecological expert behind the information on negative human impact on rainforests, email [email protected].
Effects of Human Activities on Tropical Rainforests
Logging
Logging, or the cutting down of trees, is one of the leading causes of deforestation in the tropical rainforest regions (Primack, page 3). With inaccurate or improperly recorded data on the rate and amount of trees being cut down in rural areas, such as in the Amazon Rainforest, it is difficult to tell at what rate and how much vegetation has been removed in the past few decades.
In international trading markets, particular species are sought out and logged - usually under regulations and at measured rates. Domestic markets, however, are less interested in the kind of wood produced and will log a variety of species at once, therefore increasing the rate of deforestation in that area. As infrastructure such as roads and transportation improve in more rural areas, logging has become an even more prevalent catalyst for deforestation as hunters have more access - as well as resources - to continue cutting down trees in forested areas. According to Rhett Butler, founder/editor of Mongabay.com and Yale Environment 360, the result of human activities such as "...logging, farming, ranching, and development of the Amazon have destroyed an a forest area half the size of Norway." The Amazons, although one of the largest and most necessary of the rainforest regions, is subjected to continuous human activities and lucrative industry such as soybean cultivation and cattle ranching.
Below is a chart from Richard Primack's book on ecology, tabulating the loss of rainforest area between 2000 - 2005, areas such as Indonesia and Brazil suffering from the highest rates of deforestation:
In international trading markets, particular species are sought out and logged - usually under regulations and at measured rates. Domestic markets, however, are less interested in the kind of wood produced and will log a variety of species at once, therefore increasing the rate of deforestation in that area. As infrastructure such as roads and transportation improve in more rural areas, logging has become an even more prevalent catalyst for deforestation as hunters have more access - as well as resources - to continue cutting down trees in forested areas. According to Rhett Butler, founder/editor of Mongabay.com and Yale Environment 360, the result of human activities such as "...logging, farming, ranching, and development of the Amazon have destroyed an a forest area half the size of Norway." The Amazons, although one of the largest and most necessary of the rainforest regions, is subjected to continuous human activities and lucrative industry such as soybean cultivation and cattle ranching.
Below is a chart from Richard Primack's book on ecology, tabulating the loss of rainforest area between 2000 - 2005, areas such as Indonesia and Brazil suffering from the highest rates of deforestation:
Hunting
Hunting, also known as poaching, of animals in the rainforest, has been a longstanding, transnational issue. This phenomena has been a result of increase of populated areas in rainforest areas, increased availability of guns, and improved infrastructure (Primack, page 4). According to Meghan Pastor, a specialist in biology and ethics at Salve Regina University, the hunting trade has become an extremely lucrative business, accumulating about 20 million dollars a year in profits, "...coming in third in profits after the illegal drugs and arms trades." (Pastor, page 2) The death of organisms is a natural act that occurs across our biosphere. When this occurs at unnatural rates - where the organisms themselves or those around them cannot adjust or reproduce quickly enough - this results in the endangerment of a species, where hunting is one of the various factors that contribute to this. Species interactions such as predation and pollination within the ecosystem are thoroughly harmed as a result.
Fires
Although a natural phenomena, forest fires do not usually occur in natural forests unless in periods of severe drought (Whitman, 1998; Primack, page 5). A common reason for these fires are new methods of farming brought by common or poor farmers which use fires to clear land. Due to the uncontrollable features of the fires, destruction within the forest cannot be contained and causes widespread destruction of the tree populations in the forest. This is one of the many factors leading to the drying of the soil and plant life in the rainforests, leading to the creation of more fire wood and thus more fires.
Deforestation as a result of fires - usually in the form of slash-and-burn farming - can disrupt biogeochemical processes in the tropical rainforest such as the nitrogen cycle, in which the soil is enriched with nutrients from plants and animals, leading to a decrease in general tree populations. The fires cause the disruption of processes such as nitrification because the constant destruction of the top soil on the forest floor results in a less nutrient-rich soil which can sustain exponentially less vegetation
Deforestation as a result of fires - usually in the form of slash-and-burn farming - can disrupt biogeochemical processes in the tropical rainforest such as the nitrogen cycle, in which the soil is enriched with nutrients from plants and animals, leading to a decrease in general tree populations. The fires cause the disruption of processes such as nitrification because the constant destruction of the top soil on the forest floor results in a less nutrient-rich soil which can sustain exponentially less vegetation
Deforestation
Deforestation, in the past, has been as a result of all of the above causes in various regions as well as the result of the lucrative businesses that can arise from the use of certain plant and tree populations. During the era of imperialism in the 19th century, many wars would be waged over territories with the highest resources, such as in Southeast Asia which is still a large producer of wood and logging. Today, deforestation is carried out by many poor villagers in the tropical rainforest regions and large corporations.
Much of the logging and deforestation in this biome is due to the increased need and high profits of natural resources in today's markets, which is also dependent on the unique needs and exports of a particular region. In Southeast Asia, for example, the production of rubber and palm oil have always been a rich source of profits and continue to be today. Indonesia, a primary producer of such products, suffers a deforestation rate of about 2% per year.
Much of the logging and deforestation in this biome is due to the increased need and high profits of natural resources in today's markets, which is also dependent on the unique needs and exports of a particular region. In Southeast Asia, for example, the production of rubber and palm oil have always been a rich source of profits and continue to be today. Indonesia, a primary producer of such products, suffers a deforestation rate of about 2% per year.
Invasive Species
In an ecosystem, species interactions are regulated through the availability of resources, reproduction, and living space (also called a 'niche'). Invasive species are usually foreign species introduced into a new region, introduced through natural means such as pollination or by humans. They are referred to as 'invasive' because they take over the resources, niche, and often food sources of another population of animals that leads to its decline or endangerment.
9. In what ways can you help the rainforest from your own home?
In spite of the widespread problems and transnational issues pertaining to the deforestation of the rainforest, there are still some small things that you can do to contribute to its protection.
1. Educate yourself!
Learn about where it is located, who is affected, why they are important to us, etc.
2. Join groups such as AISC's EcoClub and beyond
Contribute to conservation in your local community and abroad
3. Recycle and Upcycle
Look for the symbol on the bottom of cartons, plastic bottles, and cans to see whether they are recycable or not
Use materials that would normally be considered "trash" into art or other unique items that you could use at home
4. Be considerate of where your purchased goods come from
Many paper items and flowers in shops, for example, are taken from the rainforest as part of an illegal trading business
Question the source of these goods to ensure that you are getting your products from a reliable source
[Courtesy of Smithsonian Tropical Research Institute - http://www.stri.si.edu/sites/rainforest/save_them.html]
5. Join a tour group in one of our various travel offers on the site!
10. What is the significance of the rainforest biome to the Earth?
The tropical rainforests are vital to not only other organisms within the biome, but also the Earth and human population as a whole. Rainforests, such as the Amazon Rainforest, work to stabilize world climate, carbon in the atmosphere, and the purification of oxygen through photosynthesis. They contribute to producing about 20% of the Earth's oxygen that we breathe in everyday.
Rainforests are also valuable to humans because of the medicinal properties of the plants and their resources. According to the National Institute of Cancer Research, about 70% of medicines in cancer treatments are only found in the tropical rainforest, but less than 10% have been recognized for their medicinal properties (Mongabay).
In addition, the rainforests hold various indigenous tribes of people who have inhabited this biome for thousands of years. Recent deforestation and destruction of the rainforest has led to the decrease in populated areas of the indigenous people and their culture as a result.
Rainforests are also valuable to humans because of the medicinal properties of the plants and their resources. According to the National Institute of Cancer Research, about 70% of medicines in cancer treatments are only found in the tropical rainforest, but less than 10% have been recognized for their medicinal properties (Mongabay).
In addition, the rainforests hold various indigenous tribes of people who have inhabited this biome for thousands of years. Recent deforestation and destruction of the rainforest has led to the decrease in populated areas of the indigenous people and their culture as a result.