Ecology: Humans and their Effects on the Environment

Ecosystems can be greatly affected by human activities, both directly and indirectly.
Deforestation involves removing or clearing large areas of woodland or forest, often to make way for agricultural activities.
- This can lead to a loss of biodiversity as habitats are destroyed.
- It can also contribute to global warming, as trees absorb carbon dioxide, a greenhouse gas, during photosynthesis.
Other land use changes, such as urbanization or conversion to farmland, can similarly shrink or fragment animal and plant habitats.
Overfishing depletes fish populations quicker than they can replenish, potentially causing a collapse in the ecosystem.
Pollution, including air, water and land pollution, can degrade habitats and harm wildlife.
- For example, oil spills can destroy marine life and plastic waste can choke or entangle animals.
Human-induced climate change is another major concern.
- Rising temperatures, changing rainfall patterns and increased frequency of extreme weather events can all shift or shrink habitats
- It can also affect the timing of natural events, such as flowering and migration, potentially disrupting ecological relationships.

Conservation aims to protect and preserve biodiversity, ensuring that natural resources are used wisely and sustainably.
Ensuring sustainable development means meeting current needs without jeopardizing future generations’ ability to meet their own needs.
Approaches include creating nature reserves, legislating protection for certain species and habitats, and encouraging sustainable farming and fishing practices.
Other measures include the recycling of resources, reducing energy consumption and developing and using renewable energy sources.
Individuals, communities, countries and international bodies all have roles to play in conservation and sustainability.

Bioaccumulation occurs when an organism accumulates certain chemicals, such as pesticides or heavy metals, faster than it can break down or excrete them.
Bioaccumulation can lead to biomagnification, where the concentration of the chemical increases with each trophic level in a food chain.
This can lead to the highest concentrations being found in apex predators, potentially causing serious health effects.

Indicator species are species whose presence, absence or abundance reflects specific environmental conditions.
They can provide early warning signals of changes or degradation in an ecosystem.
Examples include lichens for air quality (especially sulphur dioxide levels), mayflies for water quality, and certain plants for soil quality.