D4.2 Stability and Change

stable ecosystem: complex interactions between a variety of species, resilience and the ability to recover from disturbances.

Stable ecosystems require:

  • a supply of energy

  • recycling of nutrients

    • The depletion of nutrients can disrupt the functioning and stability of ecosystems, as the recycling of nutrients allows for the redistribution and regulation of nutrietnts.

  • genetic diversity and interactions between species

    • An ecosystem with a higher diversity of producers will likely be more resistant to the change of biotic and abiotic factors

    • have greater capacity to asborb and recover from disturbances due to the presence of species with various strategies, tolerances, and responses to changing conditions.

  • climatic variables within tolerance range

  • resilience against disturbances

Examples of stable ecosytems

  • Tropical rainforests

    • Ex. Amazon rainforest, Congo Rainforest

  • Coral reefs

    • Ex. Great barrier reef

  • Sonoran Desert

Resistance vs Resilience

Resistance: The ability of an ecosystem to withstand or resist changes caused by disturbances without undergoing significant shifts in structure or function

Resilence: The ability of an ecosystem to resist or recover from disturbances and maintain its structure and functions.

Resistance is the ability of an ecosystem to remain stable in the face of disturbances, while resilience is the ability to recover after a disturbance.

tipping point: A critical threshold in a system where a small change can have significant and potentially irreversible effects.

  • The deforestation in the Amazon is one of the biggest ecological crises of our time and many believe that threshold for natural recovery is past

Percentage change:

mesocosm: any indoor experimental system that examines the natural environment under controlled conditions.

  • allows scientist tot control and manipulate scientist when investigating ecosystem stabilities

keystone species: specie in an ecosystem that have a disproportionately large impact on the community and their presence can help stability.

  • Play important roles in regulating populations

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 way that preserves and enhances the long-term environmental, social and economic well-being of farming systems.

    • Environmental impacts of agriculture include:

      • Soil erosion and degradation

      • Nutrient leaching

      • Fertilizer use

      • Pesticide Use

      • Transportation

    • Ex. Sustainable harvest of Silver Top Palms

  • sustainable fishing: harvesting fish at a sustainable rate, where the fish population does not decline over time because of fishing.

    • uses selective methods that maximize fish capture without affecting the population

    • depends on the rate of harvesting the fish is slower than the rate of replacement

    • maximum sustainable yield: the largest catch of fish that can be sustained over time without causing the fish stocks to decrease.

    • Ex. Pacific Alaskan Cod

eutrophication: the process by which water bodies become enriched with excessive nutrients, particularly nitrogen and phosphorus, leading to an overgrowth of algae and other aquatic plants.

  • this can disrupt the balance of the ecosystems and have detrimental effects to the ecosystem, the water quality, and aquatic life

Organisms can receive a pollutant through absorption, ingestion, or contact

  • Pollutants are usually persistent against the breakdown of the environment, leading to their accumulation within the tissues of organism

  • The concentration of the pollutant can become magnified as you succeed each level of the food chain (biomagnification

  • Plastic reaches ecosystems through ways facilitated by human activities and natural process like:

    • improper waste disposal

    • direct littering and dumping

    • runoff

    • spills

    • marine debris from fishing and shipping

rewilding: an approach to conservation and ecosystem restoration that involves reintroducing and restoring natural processes and biodiversity to ecosystems that have been degraded or altered by human activities.

ecological succession: a natural progression of changes in species composition and community structure over time.

  • Primary succession: the process of ecological change that occurs in an area that has never been colonised by living organisms or has been completely devoid of life due to extreme conditions, such as newly formed volcanic rock or a retreating glacier.

  • Secondary succession: the process of ecological change that occurs in an area that has been previously colonised by living organisms but has experienced a disturbance that disrupts the existing community and returns it to any previous stage of the development.

climax community: a stable and mature ecological community that remains relatively unchanged over an extended period of time