Resumen Habitat Change And Loss

During the history of the earth all the habitats have change dramatically by the present of humans. In this past century the habitat have degraded noticeable and exponentially by the progress of man. Human demand on the biosphere more than doubled between 1961 and 2007 (Global Footprint Network 2010). As a result, it makes a complete change in community and ecosystem states, and thus causeslosses at all levels of biodiversity. Therefore habitat degradation and loss is the number one reason of biodiversity loss. A number of human activities cause these effects and will be explained in more detail.
Impact on habitat can have two kinds of change ranges. Habitat degradation is the one that impact many but not all the species and can be temporary. In the other hand Habitat loss isimpacts that are so sever that affect all or near all species and the time span to recover is very long. In simplest terms, when a habitat is destroyed, all organisms that occupied the habitat have a reduced carrying capacity so that populations decline and extinction becomes more likely. This kind of impact can occur in land and water habitat.
Agriculture, extraction activities and developmentare the three major activities that cause habitat degradation and loss. When population growth agriculture growth with it and, with new technologies and big equipment the cultivating lands expands and biodiversity diminish. Agriculture land is been expanded about .3% annually equivalent of the size of Greece or Nicaragua. The Amazon Rain Forest lost nearly 150,000 km2 in six years by agricultureuse. Several agricultural activities are contributing of deforestation of the Amazon witch include; clearing for cattle pastures, logging, infrastructure improvement and commercial agriculture. Since 1970 cattle ranching was the leading cause of deforestation (38%) of this rain forest. However commercial agriculture of soybean has become the most important contributors to deforestation in Brazil.Brazil, followed by Argentina, is the leading producer in South America and surpassed the United States production during 2002-03. Production grew from 18 million metric ton (mmt) in 1987-88 to 51 mmt in 2002-03 (USDA). During the 2008-09 growing season Brazilian farmers planted 21.6 million hectares of soybeans. However new information from 2010/11 USDA data reveals soybean planted were 24million hectares these represent a 2.6 percent increase in area planted compared to 2009/10.
Another region affected by the commercial agriculture is the island of Borneo. This is the third largest island in the world and has an extensive biodiversity; including 15,000 plant species, more than 1,400 amphibians, birds, fish, mammals, and reptiles and unknown insects. However this islandsuffered a very drastic 50% loss of forest from 1985 to 2005. In the initial state the deforestation was due to the timber industry, later on the growth of oil palm plantation contributed to the fast loss of is forest habitat. Oil palm cultivation has expanded in Indonesia from 600,000 hectares in 1985 to more than 6 million hectares by early 2007, and is expected to reach 10 million hectares by2010. With these estimations it will be a 68% loss of this amazing place.
Generally agriculture needs another natural source to be developed and that source is been degraded too. Freshwater systems are degraded through water diversion, dams, and extensive water losses. Although less than one per cent of water on the Earth is currently accessible for direct human use the need to maintain thisresource is vital for our survival.
The major impacts on freshwater ecosystems globally include increased river fragmentation, over-abstraction and water pollution. The alarming situation of climate change is other factor that can aggravate this condition. For example the Arial Sea shrank to 40% of its original volume in one decade. The excessive use of irrigation for agriculture make the...