Changes Affecting Ecosystem Balance:
Physical and human forces that disturb ecosystem balance:
● Periods of extreme weather/climate change → an disturb balance of ecosystems
○ eg/ in 1976 – 77, south England experienced an 18 month drought → killed many trees
○ eg/ in 1987, due to storm → 15 million English trees felled (uprooted)
■ Population numbers decreased for many consumer species
● Secondary forest growth took place → trees were restored
● Consumer species have migrated back
● Ecosystems can be damaged in permanent ways when human forces are involved
○ Deforestation exposes soil beneath to rainfall → soil is easily washed away
■ Causes nutrient leaching
■ Makes it hard for ecosystem to recover
■ Takes place in tropical rainforests where heavy rain falls most days
● Long term damage: Human-induced climate change could threaten ecosystem balance
○ Changes in temperature/precipitation patternsEcosystem management:
● Killing off one species leads to an increase in another (the prey), and a decrease in another (prey of other prey)
○ eg/ bears and wolves killed
■ Increase in rabbits and deers
■ Rabbits and deers eat all available vegetation
■ Leads to soil erosion ( removal of topsoil faster than it can be replaced (top layer is nutrient rich)
● Ecosystem is no longer stable/balanced
● Scientists believe that “rewilding” is the best way to restore ecosystem balance
○ Rewilding = reintroducing animal species previously found in certain areas (form of conservation)
■ eg/ grey wolves were reintroduced into Yellowstone National Park → restored balance to the
ecosystem