1.3-a) Species increase/reduction due to human activities

Question 1

• Define ‘habitat fragmentation.

Answer 1

• Habitat fragmentation:
  ➞ results in the reduction of a large habitat area into smaller, scattered sections and can have implications for biodiversity, (including ecosystem diversity, species diversity, and genetic diversity).

Question 2

• What are the impacts of habitat fragmentation?

Answer 2

• Fragmented habitats are often lower in quality. This is known as the ‘edge effect’, where as a habitat is broken into smaller sections, the proportion of edge (where one habitat meets another) increases.
• Species that are adpated to the conditions of the interior of a woodland may struggle to survive along the edge, where the conditions are different.

1. Reduction in the total area of the habitat
2. Reduction in the average size of each patch of habitat
3. Isolation of fragments

Question 3

• What are the causes of habitat fragmentation?

Answer 3

1. Building new roads 🛣
2. Removal of hedgerows ❌️
3. Volcanic eruption 🌋
4. Clearing for agriculture 🌾
5. Rural housing development 🏡
6. Hydroelectric power 💦

Question 4

• What is habitat loss?

Answer 4

• Habitat loss:
  ➞ is where habitat destruction leaves the natural habitat unable to support species and communities within it.
• Habitat destruction:
  ➞ is the practice of deforestation that removes plant species from the soil, reducing the distribution of nutrients.

Question 5

• What are rewilding practices?

Answer 5

• Rewilding involves activities that initiate or accelerate the recovery of habitats or ecosystems with respect to their health, integrity and sustainability.
• The ultimate goal of rewilding is to create an ecosystem which requires passive management. This is done by limiting human control of the ecosystem.

Question 6

• What are examples and impacts of rewilding practices?

Answer 6

1. EROSION CONTROL:
   ➞ which prevents human impact from destabilising soil integrity (e.g., habitat destruction).
   ➞ The impact is to maintain stability and allow for flowering plants to grow 🌱
2. REFORESTATION:
   ➞ which involves planting native species in areas that would be suitable habitats.
   ➞ The impact is an increase in niches and species diversity 🌳
3. REMOVAL OF INVASIVE PLANTS:
   ➞ The impact is that it reduces interspecific competition and allows for native species to survive, reproduce and increase in population 🌵
4. REINTRODUCTION OF NATIVE AND KEYSTONE SPECIES:
   ➞ The impact is that ecosystem engineers (e.g., beavers) increase niches/habitats and manages population sizes (e.g., wolves) 🦫
5. WILDLIFE CORRIDORS:
   ➞ which link habitat fragments.
   ➞ The impact is that they help to increase the genetic diversity of species by allowing them to interbreed 🌲

Question 7

• What is a keystone species?

Answer 7

• Keystone species:
  ➞ is a species on which other species in an ecosystem largely depend on, such that the loss of the keystone species would drastically change the ecosystem.
• Example:
  ➞ Sea otters eat large quantities of sea urchins which prevents overpopulation of the urchins destroying the ecosystem.

Question 8

• What are wildlife corridors?

Answer 8

• Wildlife corridors:
  ➞ act as a link from one environment to another. They connect individual - and sometimes isolated - habitats and allow wildlife to move freely and safely between them, without threat from predators or traffic.
• This allows members of each population to interbreed, increasing genetic diversity.

Question 9

• What are harvesting practices?

Answer 9

• Harvesting practices are sustainable harvesting of (particularly) marine resources, which means:
  1. Increased food availability
  2. Decrease in habitat destruction
  3. Increase in species population

Question 10

• What is a plagioclimax community?

Answer 10

• Plagioclimax community:
  ➞ is a community that has been prevented from reaching a true climax community due to human activity.

Question 11

• What are the human activities that can cause a plagioclimax community?

Answer 11

1. Cutting down vegetation🪓
2. Burning (forest clearance) 🔥
3. Harvesting 🌾
4. Grazing (due to agriculture) 🐄
5. Planting trees or crops 🌳

Question 12

• How is a plagioclimax community maintained?

Answer 12

The plagioclimax community is maintained through:
1. Intensive sheep farming, where sheep destroy young saplings which prevents the trees from reclaiming the habitat through competition🐏
2. Controlled burning, which removes heather from the environment, allowing secondary succession to take place and replace soil nutrients (muirburn) 🔥

Question 13

• What is environmental pollution?

Answer 13

• Environmental pollution:
  ➞ results from human activity and development that occurs when physical, biological and chemical agents are released into the environment (air, water or land) in such quantities that the pollution adversely affects human health and damages the environment.

Question 14

• What is point source pollution?

Answer 14

• Point source pollution:
  ➞ is a single indentifiable source of pollution from which pollutants are discharged (such as a pipe, ditch, ship or factory smokestack).
  ➞ Discharges are often individually minor but can combine to form diffuse pollution and have a significant environmental impact.

Question 15

• What is diffuse pollution?

Answer 15

• Diffuse pollution:
  ➞ arises from land use activities spread across large areas that have no specific point of discharge.
• This includes:
  1. agricultural chemical runoff (from farmland) 🚜
  2. forestry activities 🌳
  3. urban areas 🏙️
  4. roads and sealed surfaces 🛣️
  5. industrial premises 🏭

Question 16

• What is conservation?

Answer 16

• Conservation:
  ➞ can be defined as the preservation, protection, or restoration of the natural environment and of wildlife.
• Some conservation activities include:
  1. Protecting wildlife sites 🌴
  2. Targeting action on priority species and habitats 🦧
  3. Embedding consideration of biodiversity in policy decision-making 📝
  4. Educating the public to encourgae behaviour 🍎