Describe how deforestation may affect the environment [6] #
[ZIMSEC June 2003/2/10(b)]
- removal of forestry canopy;
- rainfall cannot easily penetrate the surface runoff;
- More rapid run off;
- leads in soil erosion;
- silting of water reservours/dams/rivers;
- increases atmospheric carbon dioxide;
- results in global warming/greenhouse effect;
- reduces transpiration;
- leads to less rainfall, atmospheric moisture/drought/desertification
Effects of Human Activities on Ecosystems #
Human activities have profoundly impacted ecosystems worldwide, altering natural processes and threatening biodiversity.
Human Settlement
- Urbanization leads to habitat loss, fragmentation, and alteration.
- Infrastructure development disrupts natural habitats and creates barriers for wildlife movement.
- Example: Expanding cities encroach upon natural habitats, affecting species like birds and mammals.
Deforestation
- Clearing forests for agriculture, logging, and development reduces biodiversity and disrupts ecosystem balance.
- Loss of trees contributes to climate change, as forests act as carbon sinks.
- Example: The Amazon rainforest faces significant deforestation, impacting its biodiversity and global climate regulation.
Industrial Activities
- Industrial pollution introduces toxins, heavy metals, and pollutants into ecosystems.
- Water pollution harms aquatic life and disrupts food chains.
- Air pollution damages vegetation and contributes to respiratory problems in humans.
- Example: Industrial discharges into rivers and emissions from factories contaminate aquatic ecosystems.
Agricultural Activities
- Intensive agriculture involves pesticide and fertilizer use that can leach into water bodies, causing pollution.
- Soil erosion due to improper land management impacts soil fertility and aquatic habitats.
- Example: Runoff from agricultural fields carrying excess nutrients contributes to “dead zones” in oceans.
Mining
- Mining activities release heavy metals and chemicals into ecosystems, contaminating soil and water.
- Habitat destruction disrupts local flora and fauna.
- Example: Mining for metals like lead and mercury leads to long-lasting soil and water pollution.
Global Warming
- Increased greenhouse gas emissions from human activities lead to global warming and climate change.
- Rising temperatures disrupt ecosystems, causing shifts in species distribution and phenology.
- Melting ice caps affect polar ecosystems and sea levels.
- Example: Coral bleaching due to rising sea temperatures endangers marine ecosystems like the Great Barrier Reef.
Invasive Plant Species
- Introduction of non-native plant species can outcompete native species, leading to biodiversity loss.
- Invasive plants can alter nutrient cycling and fire regimes.
- Example: Water hyacinth is an invasive aquatic plant that disrupts water bodies, causing oxygen depletion and affecting fish populations.
Human activities have significant and often detrimental effects on ecosystems. The resulting habitat destruction, pollution, and climate change threaten biodiversity, disrupt ecological balance, and impact human well-being.
