1.15 The Impacts of Human Industry on Ecosystems

(Sec 5.4 p 126-130)

• Human activity affects ecosystems!

• Agricultural activities affect ecosystems in a number of ways:– Changing the land from a natural ecosystem (e.g.

grassland, forest) to an artificial one (e.g. pasture, fields); this vastly reduces biodiversity

• Agricultural activities affect ecosystems in a number of ways:– Addition of fertilizers can accumulate in the rivers

and lakes, and poison food.

• Agricultural activities affect ecosystems in a number of ways:– Soil degredation occurs when fertile topsoil is lost

due to erosion and/or when soil nutrients are depleted; can occur when fields are left to fallow.

• Scientists are trying to come up with ways to farm more ‘ecologically’, but maintain yields.

• Forestry practices (harvesting timber from forests) has big ecosystem effects too:

• Clear cutting completely destroy habitat (animals, plants, bacteria, soil affected)

• Firewood adds to CO2 to atmosphere (~ half of world harvest of wood burned for fuel!)

• Deforestation occurs when trees are cut and not replaced (replanted); can occur due to urban development (housing) or agriculture; habitat is totally gone

• Fisheries affect ecosystems:• Overharvesting fish can cause the ecosystem to

become unstable and collapse.

• By-catch occurs when industrial fishing operations catch non-target species, leading to ‘waste kill’ (the animals are killed for no good reason).

• Fish farming practices can lead to increased disease rates and pollution, and can have detrimental impacts on wild populations of fish and other organisms.

• Traditional ecological knowledge and wisdom (TEKW) is possessed by people of indigenous cultures around the world, who have a unique understanding of their environment, and know how to live sustainably.

• There is a growing body of interest in adopting TEKW practices in agriculture and resource management.

• In many ways, people have already taken advantage of TEKW (e.g. many western medicines derived from plants used by indigenous peoples for thousands of years).