NMES115 Session 1: Introduction to Ecosystem Services and Ecology

Ecology

  • Ecology is the scientific study of the interactions between living organisms, including humans, and their environment. It seeks to understand the distribution, abundance, and relationships of organisms within their ecosystems.

  • Key Aspects of Ecology:

    • Distribution and Abundance: Ecology examines why organisms live where they do and how many exist in a particular location. This involves understanding the factors that limit or promote the presence and proliferation of species.

    • Environmental Factors: Investigates how environmental conditions such as temperature, light, nutrients, and water availability influence the survival, growth, and reproduction of organisms.

    • Organism Interactions: Explores the relationships between different organisms, including competition, predation, mutualism, and parasitism.

Ecosystem Services (ES)

  • Ecosystem Services (ES) encompass the multifaceted conditions and processes through which ecosystems and their biodiversity contribute to sustaining and fulfilling human life. These services are essential for human well-being and societal development.

  • Detailed Categories of Ecosystem Services:

    • Provisioning Services: These involve the direct material and energetic outputs from ecosystems. Examples include:

    • Food: Production of crops, livestock, and fisheries.

    • Freshwater: Supply of water for drinking, irrigation, and industrial use.

    • Timber: Provision of wood for construction, fuel, and paper production.

    • Fiber: Supply of natural fibers like cotton, wool, and hemp.

    • Regulating Services: These maintain critical biophysical conditions necessary for human life. Examples include:

    • Water Purification: Natural filtration processes that improve water quality.

    • Crop Pollination: Pollination by insects, birds, and other animals that is essential for crop production.

    • Flood Control: Regulation of water flows by wetlands and forests to reduce flooding.

    • Climate Stabilization: Carbon sequestration by forests and oceans to mitigate climate change.

    • Cultural Services: These provide non-material benefits that contribute to human well-being. Examples include:

    • Recreation: Opportunities for outdoor activities, tourism, and leisure.

    • Aesthetic Value: Appreciation of natural beauty and landscapes.

    • Intellectual Inspiration: Provision of knowledge and ideas for scientific research, education, and artistic expression.

    • Spiritual Inspiration: Connection to nature and its spiritual significance.

    • Supporting Services: These underpin all other ecosystem services by maintaining essential ecological processes. Examples include:

    • Nutrient Cycling: Circulation of nutrients like nitrogen and phosphorus that support plant growth.

    • Soil Formation: Development of fertile soils that support agriculture and forestry.

    • Primary Production: Conversion of sunlight into biomass by plants, which forms the base of food webs.

Direct and Indirect Ecosystem Services

  • Two Broad Categories of ES:

    • Direct ES: These services directly impact human well-being and are often tangible and easily quantifiable. Examples include:

    • Water Supply: Provision of clean and accessible water resources.

    • Oxygen Supply: Release of oxygen through photosynthesis, essential for respiration.

    • Food Supply: Production of food from fisheries, agriculture, and wild harvesting.

    • Extractive Renewable Commodities: Harvesting of resources like wood and game through sustainable practices.

    • Genes: Access to genetic resources for medicine, biotechnology, and crop improvement.

    • Recreation: Opportunities for recreational activities like hiking, fishing, and birdwatching.

    • Indirect ES: These services indirectly support human well-being through their influence on ecological processes. Examples include:

    • Nutrient Cycling: Regulation of biogeochemical cycles that maintain soil fertility and water quality.

    • Atmospheric Regulation: Control of atmospheric composition and climate through processes like carbon sequestration and ozone production.

    • Climatic Buffering: Mitigation of extreme weather events like floods, droughts, and heat waves through natural buffers like forests and wetlands.

    • Waste Elimination: Natural detoxification of pollutants and waste products through biological processes.

    • Erosion Control: Prevention of soil erosion by vegetation cover and land management practices.

Importance of Ecology

  • Ecology serves as the foundation for various other branches of environmental science, providing essential knowledge and principles for addressing environmental challenges.

    • Conservation biology: Conservation of natural systems impacted by humans, e.g., the endangered riverine rabbit in the Karoo.

    • Restoration ecology: Restoring ecosystems altered by human activities, e.g., river systems damaged by invasive plants and poor farming practices.

    • Environmental engineering: Manipulation of the natural world to produce desired effects or reduce the impact of disturbances caused by human activity, e.g., flood control while still allowing rivers to function naturally.

Hierarchical Organization of Ecology

  • Hierarchical classification of living things: atoms, molecules, organelles, cells, tissues, organs, organisms, populations, communities, ecosystems, biomes, and the biosphere.

  • Ecology focuses on these four levels:

    • Organisms

    • Populations of organisms

    • Communities of populations

    • Ecosystems

Subdisciplines of Ecology

  • Organismal Ecology: Deals with how individuals are affected by and affect their environment. Example: How a gemsbok survives in a hot environment without water.

  • Population Ecology: Examines the presence, abundance, and changes in the number of species. Factors include food availability, predators, diseases, and habitat changes.

  • Community Ecology: Concerned with the composition and organization of different species populations within an ecosystem. Studies the organization of biological communities in space and time and the interactions of component populations. Example: The interaction between an antelope population and its predator population.

  • Ecosystem Ecology: Encompasses all organisms and their abiotic environment, focusing on the flow of materials and energy. Examines how nutrients enter, are recycled, and leave the system; how energy inputs do work; how energy is passed from one part to another; and how energy leaves the system.

Hierarchical Organization and Emergent Properties

  • Hierarchy reflects real hierarchy in nature.

  • Ecological phenomena are best understood by studying specific levels in the hierarchy; these phenomena are the 'emergent properties.'

  • Example: Populations are studied to understand species rarity, which cannot be understood by examining individual reproductive potential alone.

Ecology as a Science

  • The goal of science is to understand and explain the natural world and make predictions and inferences (Drake, 2010).

  • Models play a role in achieving this goal.

  • In ecology, models explain why something happens, and include the following:

    • Verbal model (statement)

    • Mathematical model (equations)

    • Graphical representation

  • Example of a mathematical model of population growth: N{2010} = N{2009} + b + i - d - e, where:

    • N_{2010} = population size in 2010

    • N_{2009} = population size in 2009

    • b = births

    • i = immigrants

    • d = deaths

    • e = emigrants