Amazon Rainforest Fragmentation

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III. Environmental Issues
Deforestation. Deforestation is one of the most critical problems in Brazil. Destroying natural habitat is a direct threat to biodiversity (Wilson et al., 2015). Historically, deforestation rates have been high in Brazil fluctuating between 25,000 to 50,000 kilometers squared per year. If deforestation were to continue at the historical rates, then most of the Amazon would disappear within 50 to 100 years (Shukla, 1990). While contemporary deforestation rates are not so severe, they are still high and have recently begun to increase. In 2009, Brazilian deforestation was estimated at 7,008 kilometers squared (May et al., 2011). After a slight decrease in the deforestation rate, with a valley in 2012 at 4,571 kilometers
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Forest fragmentation is when a patch of forest habitat is isolated by a sea of human transformed land. When a habitat is fragmented, species are killed in the destruction, while the remaining species flee into the fragment or intact area. Research has shown that forest fragments have reduced densities of key mammalian seed dispersers (Laurance et al., 2011). This decrease in mammalian seed dispersers causes a subsequent decrease in endemic, mammal-dispersed tree species (Laurance et al.,…show more content…
A habitat fragment that is too small cannot sustain species with larger ranges and populations can go locally extinct. Species richness of many organisms has been shown to decline with fragment area. Bryophytes, tree seedlings, palms, understory insectivorous birds, primates, and larger herbivorous mammals are all species that decrease in population size in smaller fragments (Laurance et al., 2011).
Habitat fragmentation also causes the alteration of local ecosystem processes leading to biodiversity loss (Wilson et al., 2015). About 70% of remaining forests in the world are within 1 km of the forest’s edge (Haddad et al., 2015). Having more edge means the fragment is more susceptible to impacts from wind, heat, and light. These changes are known as edge effects. Edge effects change the community composition of trees, lianas, and tree seedlings. Bees, wasps, flies, beetles, ants, and understory birds also decrease in abundance near fragment edges (Laurance et al.,
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