Ecosystems
The Ecosystem project
Humans get many benefits from Earth’s ecosystems. These benefits are called ecosystem services.
There are four types of ecosystem services:
Provisioning ecosystem services: resources such as foods and drinking water.
Regulating ecosystem services: including fungi decomposing waste and tree roots preventing erosion.
Supporting ecosystem services: processes that underlie all life on Earth. These include photosynthesis and the water cycle.
Cultural ecosystem services: are the ways that ecosystems benefit people’s lives and traditions such as religious, cultural and recreation connections.
A loss of biodiversity as a result of human activities can make ecosystems less healthy.
To do: Ecosystem brain dump
What are 10 things you know about ecosystems?
1. What is an ecosystem?
Getting to know you: What is an ecosystem?
Ecosystem definition: A biological environment consisting of all the living organisms (biotic components) interacting with each other and the non-living elements (abiotic components) e.g. weather, soil, air and water.
To do questions: What is an Ecosystem
Define an ecosystem in your own words
Define biodiversity.
Define a trophic level and use an annotated diagram to describe how energy moves through an ecosystem. (cough. Trophic levels)
Why are there fewer organisms at each higher level? Include an explanation of the 10% rule (Hint: Energy)
How does the loss of one or more species (declining biodiversity) affect the rest of the food web?
List the human activities that threaten ecosystems
Extra:
Which ecosystems are most at risk as a result of human activities?
2. Ecosystem Services
Introduction to ecosystem services
If we lose a few ecosystems, why does it matter?
Ecosystems provide a wide range of valuable goods and services that contribute to supporting nature and human well-being. We call these benefits ecosystem services.
Functioning ecosystems naturally provision and replenish critical ecosystem services. Human activities such as changes in land use and waste disposal, negatively impact the functioning of ecosystems.
Key questions
Describe the resources (goods) provided by ecosystems, include food, water, wood, and medicines.
Describe the services provided by ecosystems, include the regulation of climate, natural hazard mitigation, water purification, nutrient cycling, and erosion control.
Provisioning services/resources: The resources/products obtained from ecosystems, including, for example, food and fibre and fresh water.
Regulating services: any benefit obtained from the natural processes and functioning of ecosystems. Examples include climate regulation, flood regulation and other natural hazard regulation, pollination, water purification etc. For example, natural water purification services in Europe are valued at an estimated $70 -80 billion per year. Also, pollination by birds and insects is a service that would not be possible without nature.
Cultural services: The non-material benefits people obtain from ecosystems through spiritual enrichment, cognitive development, reflection, recreation, and aesthetic experience, including, e.g., knowledge systems, social relations, and aesthetic values.
Supporting services: relate to habitat functioning. For example, photosynthesis, the water cycle and nutrient cycles are the basis of ecosystems, which allow us to support ourselves. This ecosystem service also goes down to the genetic level, such as the maintenance of viable species gene pools. Ecosystem services that are necessary for the production of all other ecosystem services. Some examples include biomass production, production of atmospheric oxygen, soil formation and retention, nutrient cycling, water cycling, and provisioning of habitat.
Activity 1. Ecosystem services
To do: questions
Create a four column table; Regulation, Provisioning, Supporting and Cultural.
List examples of the ecosystem services provided by two (2) ecosystems.
Explain how a decrease in biodiversity can impact the availability of ecosystem services?
Illustrate your explanation with four (4) examples of how land use changes due to human activities impact the ability of ecosystem to provide services / resources.
Use Google Earth to annotate a satellite image of changes in land use in Brazil, how do these changes impact ecosystem services?
What is a 'ecosystem sink'? List five examples of ecosystems acting as a sink.
Extra:
How could an increase in biodiversity lead to a decline in the availability of ecosystem services?
List the potential negative impacts of climate change on mangrove ecosystem services in Bangladesh.
Case study: Biome ecosystem services
What are the ecosystem services provided by your biome?
How is your biome threatened by human activities?
Example exam question:
Identify one ecosystem that you have studied. Describe the ecosystem services that it provides and identify the threats to the ecosystem.(4)
To do: Getting to know you - Your biome here
Define your biome
Annotate a diagram of the components of your biome.
Annotate a map of the global distribution of your biome.
Annotate a graph showing the decline in the global distribution of your biome.
Create a table that lists the ecosystem services provided by your biome with examples.
Use examples to describe the threats to wetlands as a result of human activities.
3. Ecosystem components
Components of an ecosystem:
Ecosystem components are either abiotic or biotic. These components interact with one another through energy exchange and nutrient flow.
Biotic components
The living things of the ecosystem, including plants, animals and microorganisms.
Producers: Autotrophic organisms like plants and algae that can synthesize their own food using sunlight through photosynthesis. Producers capture energy from sunlight and convert it into chemical energy, which then flows through the ecosystem via food chains and food webs
Consumers: Heterotrophs that depend on producers or other consumers for food. These include herbivores, carnivores, omnivores, and parasites.
Decomposers: Organisms like bacteria and fungi that break down dead organic matter.
The human impact on biotic components
Habitat Destruction: Deforestation, urbanisation, and agriculture destroy/simplify/fragment natural habitats reducing biodiversity and genetic diversity. Deforestation may lead to soil erosion, loss of habitat affecting food webs.
Biodiversity Loss: loss of habitat/simplification leads to loss of biodiversity, species richness and or extinction, disrupt food webs and ecosystem functions.
Overexploitation: Overfishing, hunting, and harvesting of natural resources can deplete populations of certain species, leading to extinction and disrupting food webs.
Invasive Species: Introduce non-native species displace native species leads to changes in ecosystem dynamics/food webs.
2. Abiotic components:
The non-living things in the ecosystem, including the physical environment, i.e. water, wind and soil and inorganic substances. It also includes climatic factors: sunlight, temperature, humidity. These factors influence the survival and reproduction of organisms.
Climate factors: Temperature, humidity, light, wind.
Edaphic factors: Soil composition, nutrients, pH.
Topographic factors: Altitude, slope, surface exposure.
The structure and function of an ecosystem depends on the complex interactions between these biotic and abiotic components. Changes in one component can have significant effects on the entire ecosystem, highlighting the importance of maintaining ecological balance
The human impact on abiotic components
Climate Change: Global warming alters weather patterns, temperature.
Pollution: Air, water, and soil changes ecosystem balance. IE water pollution can lead to algal blooms in aquatic ecosystems, depleting oxygen levels and potentially killing fish.
Soil Degradation: Agriculture and deforestation lead to soil erosion and loss of nutrients.
Water Scarcity: Agriculture and human consumption leads to drying up of rivers, lakes, and aquifers.
To do: questions
Refer to the diagram to explain how changes in land cover can cause damage to different components of an ecosystem.
What is the impact of declining biodiversity on ecosystem components
4. Ecosystem characteristics
Characteristics of an ecosystem
Ecosystem characteristics describe the overall properties and behaviours of the whole ecosystem.
1. Energy flow and nutrient cycling (food webs/trophic levels)
2. Biodiversity and complexity - Diversity of species allows ecosystem functioning
3. Productivity - Capture energy and produce biomass
4. Stability and resilience - response to change both internal and external
5. Succession and maturity - species respond to environmental conditions
Human impacts to ecosystem characteristics.
To do: Describe how human activities impact ecosystem characteristics
Use a specific example for each of the following threats to explain how human activities impact ecosystem characteristics
Habitat loss and fragmentation: Clearing land for agriculture, urban development, and resource extraction destroys and fragments natural habitats
Pollution: The introduction of harmful substances into the environment, such as chemical runoff, plastic waste, and noise/light pollution, degrades ecosystem quality/loss of biodiversity
Climate change: alters temperature and precipitation patterns, affecting species distributions and ecosystem dynamics
Overexploitation of resources: Overfishing, deforestation, ouand excessive hunting/harvesting deplete natural resources faster than they can be replenished
Invasive species: Human activities can intentionally or unintentionally introduce non-native species to new environments
Biodiversity loss: The combined effects of habitat destruction, pollution, climate change, and overexploitation lead to a decline in species richness and genetic diversity within ecosystems
Alteration of nutrient cycles: Human activities like intensive agriculture and fossil fuel combustion disrupt natural nutrient cycles, leading to imbalances in ecosystem processes
Ecosystem simplification: Many human activities tend to simplify ecosystems, reducing their complexity and diversity. This can make them more vulnerable to further disturbances and less able to provide a full range of ecosystem services
5. The Human Impact
Background briefing: Human impacts on ecosystems
Drivers of ecosystem disruption. Habitat destruction
Habitat destruction (land clearing for agriculture, deforestation etc) typically leads to habitat fragmentation, the division of habitat into smaller and more isolated fragments separated by a matrix of human-transformed land cover. Habitat destruction is detrimental to the maintenance of biodiversity. The loss of area, increase in isolation, and greater exposure to human land uses along fragment edges (The edge effect) initiate long-term changes to the structure and function of the remaining fragments.
Causes of habitat destruction
Deforestation affects ecosystem health and functioning. Illegal timber cutting, logging, mining, and many developmental projects decrease land quality, soil health, and many other ecosystem services. Forest fragmentation negatively affects species distributions, diversity, and related ecosystem services.
Water, land and air pollution have severe impacts on ecosystem health and ecosystem services. IE eutrophication, where fertiliser (nutrients, pollutants) runoff from agricultural land causes algal blooms. This reduces the ability of subsurface plants to photosynthesise, leading to decomposition, lowering water quality and damaging aquatic ecosystems
Invasive species can be difficult to remove and can have cascading impacts on ecosystem services. Depending on the species, they can threaten food security and affect provisioning services, as insect-pollinator pollutions can decrease through competition or predation by a newly introduced species. Through competition, invasive species replace existing species.
Resource extraction: Most resource industries – logging, mining and farming – require infrastructure that transforms the ecosystem where the resource is being extracted. Intensive agriculture is also a cause of deforestation and forest fragmentation.
Positive impacts: The Great Green Wall Initiative.
Launched by the African Union in 2007, the Great Green Wall has grown from an ambitious tree-planting drive into a comprehensive rural development initiative. The goal has shifted from a literal wall of trees to transforming millions of lives by creating a mosaic of green and productive landscapes across 11 countries. So far, almost 18 million ha of degraded land have been restored.
Between 1990 and 2005, Niger lost 34.9% of its forest cover. After joining the Great Green Wall initiative in 2007, Niger experienced a 30% increase in tree cover.
List five reasons why low-income countries (LIC's) such as Niger experience deforestation.
Explain how increasing biodiversity through reforestation would impact ecosystem characteristics. In your answer, refer to the following ecosystem characteristics: water, soil, atmosphere and vegetation.
6. Case study: Deforestation in the Amazon
Forest loss and degradation is a major environmental issue. Understanding the causes of forest cover loss/degradation and its impacts on ecosystem services is relevant for sustainable management of forest ecosystems.
The Amazon rainforest is the biggest tropical forest in the world, covering some 40% of the continent of South America, spread across nine countries and 6.6m square kilometres. More than 40,000 plant species, including 1,000 different trees, have been identified in the rainforest. According to the World Wide Fund for Nature (WWF), it is also home to 427 different mammals, 1,294 birds, as well as 30 million people, including more than 220 indigenous groups.
Since 1970, almost 700,000 square kilometres of the Brazilian Amazon have been cleared.
Example exam question:
Identify and explain one environmental impact of land use changing from a natural ecosystem to agricultural production. (3 marks)
To do: Deforestation case study
Create a 3 part case study that examines the impact of a human activity (land clearing for agricultural production) on a the Amazon forest ecosystem.
Deforestation rates in the Amazon
Causes of deforestation
The impact of deforestation in the Amazon
7. Conservation strategies
Species loss in the Amazon caused by deforestation
An international team, conducted a detailed analysis of nearly 2,000 species of plants, birds, beetles, ants and bees that were found across more than 300 diverse sites in the Brazilian Amazon. They found, that where forests had been cleared for cattle ranching and agriculture, biodiversity declined and plant and animal life was impoverished.
Example exam question: Identify and explain conservation strategies for an ecosystem you have studied. (5)
To do: Use the following article to briefly outline the conservation strategies you would implement to manage a forest reserve.
Six ways Brazil is conserving the Amazon - howtoconserve.org
1. Protected areas (National Parks etc.)
2. Industry cooperation (Boycotts etc.)
3. Satellite monitoring (Illegal clearing etc.)
4. Improved enforcement (Fines, publicity etc)
5. International action (Carbon credits)
6. Domestic political actions (Community, NGO's and Political actors)
Radical Ideas: The conservation benefit of secondary forests
Deforestation through logging, fire and farming had a major effect on species loss and simplification across large areas. There remains a widespread assumption that concentrating conservation efforts on the protection of isolated reserves is the best way we can safeguard biodiversity. However, disturbed (secondary) forests are able to maintain up to 80 per cent of the biodiversity found in pristine forests.
To preserve maximum species diversity, reserves should not be concentrated in one part of a region, but as a widespread network of forest reserves. These should include secondary forests where no primary forests remain.
Lower species diversity in degraded forests also indicates that many species are restricted to undisturbed forests. This demonstrates the importance of controlling selective logging and preventing wildfires in all forests, including those on private lands that have already been disturbed.
The high variation in biodiversity found in secondary forests indicates the role these ecosystems play in regional conservation. For many areas of the Amazon, conserving existing secondary forests may be much cheaper and even more efficient than planting trees.