Stability and change of ecosystems

Stability

The ability to mantain or support systems and processes continuosly over time.

Stable ecosystems

• Tropical rainforests: Contain 50% of world’s plant and animal species.

• Coral reefs: 25% of ocean’s fish depend on coral reefs. They have existsed for 200 million years

• Boreal forests: able to withstand wide range of environmental conditions. Have existed for over 10,000 years

• Sonorean desert: Supports more plant species than any other desert, despite being the hottest desert in America.

Factors that contribute to ecosystem stability:

• Supply of energy

• Nutrient recycling

• Genetic diversity

• Climate

Outline how continual supply of energy affects ecosystem stability.

The sun is the main primary source of ecosystems, but not all organisms can use it directly. Diverse producer ecosystems are more resilients to changes and ensure a balanced energy flow for stable ecosystems.

Outline how nutrient recycling affects ecosystem stability.

Nutrients like carbon, nitrogen and phosphorus circulate between organisms and the environment. Efficient recycling ensures nutrient availability, supporting ecosystem productivity and stability.

Outline how genetic diversity of organisms affects ecosystem stability.

Genetic diversity means that there are many organisms in an ecosystem with different traits. This allows for certain organisms to have random mutations that benefit them and increase fitness. This allows for better tolerance to changes, known as resilience.

Outline how climate affects ecosystem stability.

Physical factors like climate and topography impact ecosystem stability. For example, some organisms are adpeted to survive in certain conditions (temperature, pH).

Tipping point

Critical threshold where ecosystem undergo irreversible change due to small cumulative disturbances.

Reasons for deforestation

• Farming

• Illegal logging

• Building houses

• Wildfires

• Paper

Describe how rainforests influence the local water cycle, temperature and airflow.

• Water cycle: Plants absorb water from the soil and release it to the atmosphere through transpiration. This reduces runoff, which increases rainfall and soil moisture

• Temperature: Transpiration process cools the environment and creates a moderate climate

• Air flow: Large scale deforestation can disrupt weather patterns. This leads to changes in wind pattern, impacting local climates.

How does the size of an area of a rainforest affect the generation of atmospheric vapour?

A large area of rainforest is needed for the generation of atmospheric vapour by transpiration, with consequent cooling, air flow and rainfall.

What are possible consequences of deforestation?

• Biodiversity loss

• Climate change

• Water cycle disruption

• Soil erosion

• Desertification

Mesocoms vs natural ecosystem to investigate changing conditions

Mesocoms:

• Advantage: Able to control variables, precision

• Disadvantage: Unrealistic.

Natural ecosystems:

• Advantage: Realistic

• Disadvantage: Minimal control over controlled variables

Keystone species

A species that plays a critical role in mantaining the structure and functioning of an ecosystem.

Example of keystone species

Bees: support the reproduction of 80% of the world’s flowering plants.

What happens if if the population of keystone species becomes unbalanced?

• Trophic cascade

• Habitat modification

• Nutrient cycling and ecosystem processes

Keystone species case study

Wolves in yellow stone: Wolves in yellowstone were removed in 1926 → Elk population starterd to rise → Plant diversity decreased → Land erosion increased.

Sustainability

The capacity of meeting the needs of the present generation without compromising the ability of future generations

Sustainability in agriculture

The practice of cultivating and producing agricultural products in a manner that preserves and enhances the long-term environmental, social and economic well-being of farming systems.

Factors that effect agricultural stability

• Soil erosion

• Supply of fertilizers

• Leaching of nutrients

• Carbon footprint

• Monocultures

• Overuse of water

Autriphication

The process by which bodies of water become enriched with excessive nutrients, particularly nitrogen and phosphorus.

Bioaccumulation

The process by which certain substances, such as toxins or pollutants, accumulate and increase in concentration within the tissues of organisms over time.

Biomagnification

The increase in the concentration of certain substances, such as toxins or pollutants, at higher levels of the food chain.

Microplastics

Small plastic particles or fragments that measure less than 5mm.

Macroplastics

Large pices of plastic debris that are visible to the naked eye.

Effects of plastic pollutions

• Disruption of marine food webs

• Chemical pollution

• Wildlife entanglement and ingestion

• Habitat degradation

Effects of plastic pollution on marine food webs

Small marine organissm feed on microplastics and are then consumed by larger organisms. This transfer of plastics through the food chain can have a cascading effect.

Effects of plastic pollution on chemical pollution

Microplastics can absorb and release harmful chemicals. When they are consumed, they can exposed fish to toxic chemicals, having detrimental effects on their health. they also act as carriers of pullution.

Effects of plastic pollution on wildlife entanglement and ingestion

Plastic items, such as fishing nets, ropes and sixpacks can entangle animals and cause injuries.

Effects of plastic pollution on habitat degradation

As plastic accumulates, it can damage sensistive habitats, hindering their ability to provide food and shelter.

Rewilding

The process of restoring and reintroducing natural ecosystems and species to areas where they have been lost or significantly altered.

Rewilding methods

• Species reintroduction

• Habitat restoration

• Rewilding urban areas

• Rewilding rivers and waterways

• Ecological management and natural processes