Conservation of Biodiversity (Cambridge (CIE) AS Environmental Management)
Revision Note
Written by: Alistair Marjot
Reviewed by: Bridgette Barrett
Native & Invasive Species
Native species is the term given to species that have originated, evolved and developed in a specific ecosystem or region and are highly adapted to living in that area
An invasive species is a species that has moved into a new ecosystem where it was previously unknown:
An invasive species can occur naturally as a result of a species migrating or expanding their habitat but most recorded incidents of invasive species have been caused by humans
In the past humans have:
Knowingly collected and traded species between countries via ships and aeroplanes
Unknowingly provided transport for invasive species to a new ecosystem (for example, rats were often living aboard explorers' ships when they landed in new locations – the rats would then leave the ship and become an invasive species)
Introduced alien species deliberately as biological control for pests
Case Study
Japanese knotweed (Reynoutria japonica) is the UK’s most invasive non-native plant species.
There are several natural population controls that exist for Japanese knotweed in its natural habitat in Japan. The irregular climate and the deposits of volcanic ash over the ground limit its growth.
A German botanist brought the plant to the UK in the 19th century because he admired its beauty.
As the UK does not possess the same environmental factors as Japan, the plant was able to grow unchecked. Since the 1800s it has spread across the UK and become a major problem.
It grows at a rapid rate, breaking up tarmac and blocking out sunlight for many of the UK's native plant species, as well as outcompeting them for water, nutrients and space to grow.
Problems Caused by Invasive Species
The biological process of evolution often brings balance to an ecosystem
Through evolution, the environment a species lives in strongly influences the adaptations that the species evolves in order to survive and reproduce successfully in that environment
An invasive species will have evolved adaptations for survival in different environmental conditions, so when they are introduced into a new ecosystem they can upset the balance
In a new ecosystem, invasive species will have little or none of the natural population controls that existed in their previous ecosystem:
For example, they will have no natural predators or competitors
As a result they are able to increase in number at a rapid rate
This can affect the processes within an ecosystem:
Competition may occur between invasive species and native species that occupy a similar niche, with the native species getting displaced, outcompeted or eventually even pushed to extinction. It could be competition for things such as prey, soil nutrients, light and space
Many invasive species are highly successful predators, which can potentially cause a rapid decline in their prey species (particularly if these prey species are not well adapted to this new predator)
For example, the introduction of the brown tree snake (Boiga irregularis) to Guam led to the rapid decline and extinction of many native bird species due to the snake's predation on bird eggs and nestlings
Invasive species can introduce new diseases, to which the native species have no natural immunity
The biodiversity of an ecosystem is negatively impacted, which reduces its overall productivity
Humans can also feel the knock-on effects of an invasive species taking over an ecosystem:
The economy of a country can be impacted by the financial costs of trying to control invasive species and their negative effects
Case Study
The Cane Toad in Australia
In the early 1900s, there was a major problem with the sugarcane crop in Australia. An insect pest was destroying the crop and causing major economic losses for many farmers.
It was decided that a non-native toad species known as cane toads (Rhinella marina) should be introduced so that it could act as a biological control, by predating on the pest insects.
After a short period of time, the numbers of these toads increased rapidly due to a lack of natural predators and they spread into other habitats outside of the sugarcane plantations.
This continues to have knock-on effects on other native species:
The cane toad is toxic when eaten:
As a result, the northern quoll (Dasyurus hallucatus), which is an endangered marsupial carnivore, declined steeply in numbers as they preyed upon the cane toads
Other native amphibian species face increased competition for food and resources
The eggs of ground-nesting birds are often eaten by cane toads
Benefits of Conserving Biodiversity
Resources of Potential Medicines
Biodiversity is a significant source of potential medicines that are yet to be discovered:
Over half of all pharmaceuticals come from natural sources, with plants being a major source
Many medicines derived from nature are already being used to treat diseases like cancer, malaria and heart disease
Conserving diverse ecosystems, such as tropical rainforests, ensures a wider range of potential medicines for future discovery
For example, quinine, used to treat malaria, comes from the cinchona tree found in South America:
Deforestation threatens its availability, highlighting the importance of habitat preservation
Food, Wood, Fibres, Oils and Fuels
Biodiversity is vital to our food security:
Diverse ecosystems with healthy populations of pollinators (e.g. bees, butterflies) ensure efficient crop pollination, leading to higher yields
Biodiversity also provides diverse food sources and helps maintain soil fertility
Wood, fibres, oils and fuels:
Forests and other diverse ecosystems provide us with timber, cotton, palm oil, biofuels and other resources
Sustainable use and conservation are crucial to avoid depletion and maintain these resources for future generations
For example, the loss of coral reefs threatens fisheries, impacting food security for millions:
Conservation efforts are vital to protect these ecosystems and their resources.
Diversity in Genes
Genetic diversity within species enhances their resilience to diseases and environmental changes:
By conserving biodiversity, we protect this genetic diversity, ensuring species' survival and their continued ability to adapt and evolve in a rapidly changing world
Protecting genetic diversity amongst other species can also directly benefit humans in many ways:
For example, diverse rice varieties with different disease resistance traits are crucial for agricultural sustainability
Conserving these varieties improves food security in the face of potential disease outbreaks
Ecological Services
Healthy ecosystems offer numerous ecological services essential for life:
These include water purification, air filtration, flood control and soil conservation, as well as many others
Biodiversity loss disrupts these services, ultimately impacting human health and well-being
Combating climate change:
Forests and other ecosystems (e.g. seagrass beds) absorb carbon dioxide, mitigating climate change
Conserving these carbon sinks is crucial for tackling the global challenge of climate change
For example, mangrove forests protect coastlines from storms and floods, while also storing large amounts of carbon:
Their conservation not only protects local communities but contributes to climate change mitigation too
Cultural and Recreational Value
Biodiversity enriches our lives culturally and recreationally
Nature provides inspiration for art, music and literature
It also offers opportunities for outdoor recreation, improving physical and mental health
Cultural significance:
Many cultures have deep connections to specific species and ecosystems
Conserving biodiversity helps preserve these cultural values and traditions
For example, ecotourism relies on healthy ecosystems and diverse wildlife:
Conservation efforts not only protect nature but also support local economies and cultural traditions
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