Biomes

Biome: is a large geographical area of distinctive plant and animal groups, which are adapted to that particular environment. The climate and geography of a region determines what type of biome can exist in that region. Some parts of the earth have more or less the same kind of abiotic and biotic factors spread over a large area, creating a typical ecosystem over that area. Such major ecosystems are termed as biomes. Biomes are defined by factors such as plant structures (such as trees, shrubs, and grasses), leaf types (such as broadleaf and needleleaf), plant spacing (forest, woodland, savanna), and climate. 

All living things are closely related to their environment All living things are closely related to their environment. Any change in one part of an environment can cause a ripple effect of changes. No living organism lives alone. Each depends in some way on other living and nonliving things in its surroundings.

To understand a world biome, you need to know: What the climate of the region is like. Where each biome is found and what its geography is like. The special adaptations of the vegetation. The types of animals found in the biome and their physical and behavioral adaptations to their environment.

The major world biomes based on natural vegetation are: Tundra Boreal or Taiga Forest Temperate Deciduous Forest Schlerophyll Forest Temperate Grassland Deserts Tropical Rainforest Tropical Savannah Complex Highland Vegetation

Tundra

Schlerophyll Forest

Boreal or Taiga Forest

Temperate Deciduous Forest

Temperate Grasslands

Desert

Tropical Rainforest

Tropical Savanna

Highland/Alpine

When studying biomes, it is important to keep in mind the interconnectedness of all things. Every biome, vegetation, soil, and animal inhabitants is a system. If humans change one part of that system, it will alter the whole system. These changes often go unseen at the time. Ex: Tropical rainforest is being cut down at a rapid rate, and because of this, many animals are becoming extinct.

Animals in the tropical rainforest depend on their habitat in order to survive, and when this is lost due to deforestation, than animal life is often lost. The tropical forest is a carbon sink, and when these “lungs of the Earth” are reduced, more carbon dioxide is entered into the atmosphere (contributing to global warming). Trees in the tropical forest transpire a large amount of water back into the air. Without this occuring, an increase of aridity (lack of sufficient rainfall) around the globe could result.

From the article on deforestation of the tropical forest, why were humans cutting down trees? What kind of impacts have resulted?

Farms (subsistence Farming) Harvest timber for both fuel and construction Expanding urban areas Building Road/Infrastructure Industrial Cattle ranching Poor countries expand economic development to support the global market Soybean production Replacing of tropical forest for commercial palm tree plantations (bio-fuels) Poverty (new economic policies by gov’ts that focus on expansion). Foreign debt. Technology Calculation of rate of deforestation Reduces biodiversity (have about 1/2 of all Earth’s species) Soil can no longer get its nutrients from the living plants and decomposing litter on forest floor Increased flooding Indigenous populations are displaced, leading to violence The tropical forest maintains rainfall, and the evaporation helps cool the Earth’s surface. Rainfall patterns may be disrupted. May also create heat islands that speed up evaporation and precipitation at a local level. These forests take in about 10 years worth of human generated greenhouse gases. Prone to fires.

What suggestions are made in the article to help preserve the tropical forests of the world? Why might some of these suggestions not work?

Establish large, pristine, uninhabited protected areas, even if that means removing current residents Gov’t and Non-Gov’t organizations working directly with forest communities on how practice low impact agriculture. Support ecotourism of protected areas to provide local employment, educational opportunities, and service-sector economies. More research done on human impacts on the tropical forest, and incorporate this knowledge when planning land use and economic development plans. Some scientists don’t think protected parks are the answer. Based on their research, less deforestation occurred in areas occupied and managed by indigenous populations. Protected areas tended to have a lot of illegal logging taking place. On the international and national scale, the marketplace needs to value products that are certified as sustainably produced. Part of this is providing incentive for landowners. Forest preservation policies.

Each biome will provide different resources for human consumption Each biome will provide different resources for human consumption. A lot of what a biome can produce, is based on soil type. Each Biome also contains different management concerns.

Resource Examples: Boreal forests- softwood Tropical forests- hardwood Temperate grasslands- grain farming (due to chernozem soils) Areas like the Canadian Shield- minerals Biomes with active volcanoes- geothermal energy and enriched soil due to volcanic ash.

Interactions Between Human Activity and Biomes The systemic nature of biomes make them fragile. They are so interconnected that if one component is disturbed, this sets off a series of unforeseen changes. A disturbance can be natural, such as, a forest fire, and this will cause a short term change in the ecosystem. A change, such as, climate change will have a more profound impact. The whole ecosystem will have to adjust to the new climate. As plants and animals adapt, the whole ecosystem will be altered.

Homeostasis- systems will always work towards achieving balance Homeostasis- systems will always work towards achieving balance. This is achieved through positive and negative feedback. Positive feedback enhances processes. For example: A year experiences a good amount of rainfall, lots of vegetation growth occurs, and thus the rodent population continues to grow. If the food supply continues to grow, the rodent population is able to grow. Negative feedback can bring things back into balance. For example: If the rodent population continues to grow, there would be too many, and the system would not be in balance. However, when the rodent population expands, predators, like wolves, have a source of food and expand in population size. The expanding wolf population would bring things back into balance, and are the negative feedback in this example.

What about humans? We are on the top of the food chain, and keep on expanding. We have cut down forests to make room for our population, we use pesticides to help us cultivate food, dump our excess waste into water systems and the ground, have polluted our atmosphere through our activities, and have caused the extinction of various species. The more humans do this, the more human life that can be supported. This is quite the positive feedback!

The positive feedback created by humans impacts the homeostasis of the Earth. At some point negative feedback has to come into play, but we do not know what form that will take. The whole ecosystem could completely collapse, new diseases may develop, human behavior may change over time and Earth will continue to thrive. Whatever the consequences, humans are facing very significant changes in the future when it comes to living within the ecosystem.