BIOLOGICAL IMPACT ON TROPICAL SPECIES. Nicole (Cheng) Chan \ ID #

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1 BIOLOGICAL IMPACT ON TROPICAL SPECIES Nicole (Cheng) Chan \ ID #

2 Danger of losing bio-diversity & species in the tropicals What is biodiversity again? Life, the world, the variation of life for the entire globe. How much diversity of life is on this Earth? According to the IUCN, humans know about an estimated 1,562,663 different life forms on this planet, that s like : * 5,416 mammals * 16,000 mushrooms/fungi * 29,300 fish * 950,000 insects * 287,655 plants About the species in tropical rainforest? A 4-square-mile (1,000 hectare) patch of rain forest contains up to: 1,500 species of flowering plants (as many as 750 species of trees) 125 species of mammals / 400 species of birds / 150 species of butterflies 100 species of reptiles / 60 species of amphibians. Loss of species & biodiversity BIOLOGICAL IMPACT

3 Bio-diversity simply means the diversity, or variety, of plants and animals and other living things in a particular area or region. It also means the number, or abundance of different species living within a particular region. Scientists sometimes refer to the biodiversity of an ecosystem, a natural area made up of a community of plants, animals, and other living things in a particular physical and chemical environment. In practice, biodiversity suggests sustaining the diversity of species in each ecosystem as we plan human activities that affect the use of the land and natural resources. According to the IUCN (International Union for the Conservation of Nature), humans know about an estimated 1,562,663 different life forms on this planet. Including the following on the screen*. Many experts feel we have still to discover many more species - some estimates say we have yet to discover and describe millions of new lifeforms. Although tropical rain forests now cover just 2 percent of the globe, they are home to more than half the world s living plant and animal species. According to a report by the United States National Academy of Sciences, a 4-square-mile (1,000 hectare) patch of rain forest contains up to 1,500 species of flowering plants, as many as 750 species of trees, 125 species of mammals, 400 species of birds, 150 species of butterflies, 100 species of reptiles, and 60 species of amphibians. It is not only quantity of life, but diversity as well, that makes rain forests so vital. Some of the strangest and most beautiful plants and animals are found in rain forests, and undoubtedly there are just as many we do not even know about. Tropical forests vary greatly according to altitude, region and species of trees. Each has a different micro-climate, soil type, fauna and flora. They grow in tropical latitudes 30 degrees to the north and south of the Equator. Among the many types of tropical forests are evergreen wet forests, deciduous dry forests, mountain cloud forests, and mixed lowland rainforests. In general, lowland rainforests are the most biologically diverse, as well as the most endangered. Covering only 7 percent of the Earth s surface, rainforests harbor half its species. Biological research in tropical forests has consistently shown that this great diversity helps stabilize ecosystems and the very life support systems of the planet. Some tropical forests have been characterized as hotspots, having exceptionally high diversity of endemic species that are found nowhere else on Earth. The tropical forest hotspots include the Caribbean, Central America, Brazil s Atlantic Rainforest, western Ecuador s Choco region, Andean tropical forests, Indo-Burma, the Philippines, Indonesia and Peninsular Malaysia, the Western Ghats of India, Madagascar, New Caledonia, Polynesia and Micronesia, Guinean Forests of West Africa, and mountains and coastal forests of Tanzania and Kenya. However, Humans already have destroyed half of this forest area, with most damage occurring in the last 200 years. With just 2.5 million square miles (647 million hectares) of tropical rain forest remaining, we continue to lose an estimated 93,000 square miles (150,000 square km) a year. so... SOURCE 1. California Biodiversity Council, 2. WWF, 3. Bagheera: In The Wild, NOTES slides one

4 What about global warming? The Science study notes that tropical climates have warmed more than 1.4 degrees Fahrenheit since 1975, and climate models predict an additional increase of nearly 6 degrees over the next century in the tropical forests of Central and South America. Loss of species & biodiversity BIOLOGICAL IMPACT

5 There is a direct link between rising carbon emissions from human sources, rising temperatures and endangered species. The Science study notes that tropical climates have warmed more than 1.4 degrees Fahrenheit since 1975, and climate models predict an additional increase of nearly 6 degrees over the next century in the tropical forests of Central and South America. Data collected on the altitudinal ranges of nearly 2,000 plant and insect species living on the forested slopes of a Costa Rican volcano rises some 10,000 feet! It is found that about half the species have such narrow altitudinal ranges that a 2,000-foot uphill shift caused by warming temperatures would move them beyond the upper limits of their current ranges. Researchers also found that many species may be unable to shift because mountainside forests in the tropics have been severely fragmented by human land use. Tropical climates have warmed (more than 3/4 degrees Centigrade/1.4 F since 1975), and climate models predict an additional increase of more than 3 degrees Centigrade (nearly 6 degrees Fahrenheit) over the next century in the tropical forests of Central and South America. This much warming would shift temperature zones uphill about 600 m (nearly 2000 feet) in elevation above sea level. Tropical species, like those at higher latitudes, will likely be driven to higher elevations by these changes, following the climate zones they are suited for. Most of the increases in atmospheric CO2 concentrations come from the use of fossil fuels (coal, oil, and natural gas) for energy, but few realize that about 25 per cent of all global emissions come from deforestation and changes in land use, like the clearing of forests and the cultivation of soils for food production. Graph A show show how much CO2 will be released into the atmosphere- this estimates depend upon population and economic projections, future choice for energy, governance/policy options in development. This is how much it will affect population growth, econmoic growth, tecnololgocial growth etc. See the big different the CO2 emissions can make? It definitely affect every aspect of growth on earth. Graph B shows a projecton of annual average precipitation ( minus ). Looks like there are tons of drying at the sub-tropics and tropics. And it is projected to be even more. SOURCE 1. Lecture slides on 1/28, page 10 & 13 [IPCC 2007] 2. Science Daily, NOTES slides two

6 Why is the warming of tropical is as bad, or even worse than others? Many species are getting affected by the temperature change, including the infamous case of the polar bears and penguins. However... A 1-degree temperature change in Panama will not be felt the same way by an organism as a 1-degree temperature change in Alaska! Loss of species & biodiversity BIOLOGICAL IMPACT

7 Until today, the scientists priority has been the research of the climate changes influence on species in the poles, for instance the polar bear. Those animals though, seem to be used to those changes of temperature, in contrast to those that live in the tropical zones. Polar bears are in danger, but its just for different reasons than for tropic species. It s not the temperature itself that will harm the bears they already live in a climate that varies wildly throughout the year what will harm them is the loss of habitat they will face as polar ice disappears. Even if the climate changes consequences are expected to become more noticeable in the poles, scientists report that it s possible to also cause a greater threat for the species that live in the tropical zones. Tropical species are used to live under small temperature ranges, thus, according to a published analysis in a weekly edition of Proceedings of the National Academy of Sciences (PNAS), they might not be able to face even variabilities of a few degrees. Many tropical species can only tolerate a narrow range of temperatures because the climate they experience is pretty constant throughout the year. While temperature changes will be much more extreme at high latitudes, tropical species have a far greater risk of extinction with warming of just a degree or two. That is because they are used to living within a much smaller temperature range to begin with, and once temperatures get beyond that range many species might not be able to cope. As temperatures fluctuate, organisms do what they can to adapt. Polar bears, for example, develop thick coats to protect them during harsh winters. Tropical species might protect themselves by staying out of direct sunlight in the heat of the day, or by burrowing into the soil. But again, since they already live so close to their critical high temperature, just a slight increase in air temperature can make staying out of the sun a futile exercise, and the warming might come too fast for creatures to adapt their physiologies to it. So does that mean that we should turn our focus away from the Arctic? Definitely not! Many tropic species will actually likely be harmed directly from the rising temperature itself since their physiology cannot handle the vastly swaying temperatures like the bears can. And it is these desert areas that sit on the edge of tropical locations, such as the U.S. Southwest, parts of the Mediterranean, and of course Australia, that are at the most risk, according to the experts. While warming is happening much faster at higher elevations, it is also occurring at a slower rate in tropic zones, which over time will likely just as severe of an impact, but for different reasons. They may not be as majestic as polar bears, but we can t forget about the little guys. In the chart: scientists used daily and monthly global temperature records from 1950 through 2000, and added climate model projections from the IPCC for warming in the first years of the 21st century. They compared that information with data describing the relationship between temperatures and fitness for a variety of temperate and tropical insect species, as well as frogs, lizards and turtles. Fitness levels were measured by examining population growth rates in combination with physical performance. SOURCE 1. Lecture slides on 1/28, page WWF, 3. Science Daily, 4. The daily Galaxy, NOTES slides three