Nicole Salapic 20569556 BIOL 225- Topic 28 Describe some key human activities that contribute to biological diversity decline. Why is such biodiversity decline a threat to us? Some human activities that contribute to biological diversity decline are land/ forest fragmentation, the addition of pollutants, and excessive hunting, fishing and gathering (RFC, 2018). But, the human activity I will focus on will be land fragmentation. Some reasons why fragmentation occurs are due to urbanization, agriculture, transportation, deforestation and to extract resources (RFC, 2018). Fragmentation eliminates habitats for those species requiring large unbroken fragments of habitats (Rogan and Lacher, 2018). The fragments are surrounded by unstable habitats (Stein, 2001). There are fewer places for settling and protection and there is a shortage of food (Rogan and Lacher, 2018). Migration is also disrupted which makes it harder for animals to move from one place to another (Rogan and Lacher, 2018). The open land makes them more susceptible to other predators (RFC, 2018). Animals dependence is lost slowly and can eventually lead to local extinction (Rogan and Lacher, 2018). As the larger animals disappear there is a shift in the prey population (RFC, 2018). Most prey feed on seeds and with an increase in their population it leaves fewer seeds from being germinated (RFC, 2018). Most of the information presented can be summed up by the “edge” effect. When an edge is created to any natural ecosystem and the area outside the boundary is disturbed, the natural ecosystem is affected for some distance in from the edge (Stein, 2001). There is an increase in edge habitats and a decrease in interior habitats (Stein, 2001). The edges expose the remaining species within the forest to different surrounding ecosystems, reshapes the interactions between species, hosts, and pathogens by affecting both abiotic and biotic conditions (Stein, 2001). Creating an open land/ forestry boundary, sunlight and wind penetrate much more, drying out the interior of the forest close to the edge (Stein, 2001). Tree mortality increases near the edges and genetic diversity in the forest declines (Rogan and Lacher, 2018). Air temperature, soil moisture, and light intensity all change at the edge (Stein, 2001). The decline in biodiversity is a threat to us because without it there would be no human survival (Morton, 2015). It is essential to the economic, ecological, cultural, scientific and recreational factors of everyday human life (Morton, 2015). The most interesting point on this topic is how humans are not aware of the things that they are doing and don’t look at the future effects. This is interesting to me because being unaware of things now produces problems that will be hard or impossible to fix in the future. Nicole Salapic 20569556 BIOL 225- Topic 28 References 1. 5 Causes of recent declines in biodiversity. (n.d.). Retrieved October 8, 2018, from http://www.rainforestconservation.org/rainforest-primer/2-biodiversity/g-recent-losses-inbiodiversity/5-causes-of-recent-declines-in-biodiversity/ (RFC,2018) 2. Morton, S. (2015, February 24). Chapter 1. What is biodiversity, and why is it important? Retrieved October 8, 2018, from https://www.csiro.au/en/Research/Environment/Biodiversity/Biodiversity-book/Chapter-1 3. Rogan, J. E., & Lacher, T. E. (2018). Impacts of Habitat Loss and Fragmentation on Terrestrial Biodiversity. Reference Module in Earth Systems and Environmental Sciences. doi:10.1016/b9780-12-409548-9.10913-3 4. Stein, R. (2001). Lyme Disease. Encyclopedia of Environmental Health, 528-534.