9.10 - Human Threats to Biodiversity

Question 1

What does HIPPCO stand for

Answer 1

• Habitat Fragmentation/Loss - Deforestation (lumber, cities, roads) Wetland draining (ag, urbanization)
  River water level decreased by dams
• Invasive Species - Invasives such as z. mussel and kudzu vine outcompete native species for food/space, lowering populations
• Population growth - Human pop. growth drives hab. loss, Urbanization, ag. expansion to feed more people remove/fragment hab.
• Pollution - Oil spills reduce marine org. pop. sizes
  Pesticides (glyphosate, atrazine) kill non-target species
• Climate Change - Shifts biomes & therefore species habitat ranges, can change temp. & precip. patterns too rapidly for a species to adapt or migrate, causing pop. decline or extinction
• Over exploitation - Excessive hunting or poaching (faster than reproductive rate) leads to pop. decline & potential extinction

Question 2

What is habitat fragmentation?

Answer 2

Breaking of larger, continuous habitats into smaller, isolated patches; disrupts breeding, hunting, migration

Question 3

What are things that cause habitat fragmentation?

Answer 3

• Roads & Pipelines - Roads & oil/gas pipelines fragment habitats; disrupt movement & lead to fatal collisions with vehicles
• Agricultural & Urban Land Use - Clearing forest/grassland for ag. fields or urbanization fragments those habitats.
• Logging - Both removal of trees & construction of logging roads to transport lumber fragment forest ecosystems

Question 4

What are metapopulations?

Answer 4

mostly isolated, subpopulations connected by habitat corridors; this can allow some gene flow (mating between populations) and improve genetic diversity

Question 5

How does habitat fragmentation relate to metapopulations?

Answer 5

• Some species are more disrupted by fragmentation than others
• Large predators needing large hunting space
• Smaller populations of large k-selected mammals may struggle to find mates
• habitat Fragmentation creates smaller, isolated subpopulations
• Smaller subpopulations have less genetic diversity, are more prone to inbreeding depression, and are less resilient to env. disturbance or disease - creates metapopulations

Question 6

What is the edge effect?

Answer 6

two ecosystems such as forest-grassland or ocean-river (estuaries) meet have diff. characteristics than the middle of each ecosystem

Question 7

What is the result of the edge effect?

Answer 7

• Some species thrive in the edge habitat & biodiversity is often higher in edge habitats due to diversity of food, shelter, and nutrient resources
• Edge habitats can expand range of potentially disruptive species (ex: brown headed cowbird) that thrive in grassland-forest edge
• Brood parasite that leaves its eggs in the nests of songbirds for them to raise, unknowingly

Question 8

What can climate change do?

Answer 8

Climate change can shift the range of habitats, or increase/decrease their range altogether

Question 9

Types of climate change

Answer 9

Temperature change
- Warming temp. can shift biomes
- Boreal forest & temperate coniferous forests may
shift northward; tundra may decrease

Precipitation change
- Warming global. temp. will decrease precipitation in some areas, leading to soil desiccation and desertification
- Will increase in some areas, expanding tropical
ecosystems

Sea level rise
- Estuary habitats (salt marshes, mangroves) become fully submerged & more saline; coastal ecosystems become flooded

Question 10

Relationship between biodiversity and domestication

Answer 10

Domestication of species for agriculture generally decreases genetic and species biodiversity

Question 11

Effects of biodiversity and domestication

Answer 11

Crops
- Fewer plant species are grown as selective breeding and GM results in only the highest yield species
- GM use and selective breeding also lead to less genetic diversity in crops, making them more vulnerable to disease or environmental disruptions

Live stock
- Historically, there have been over 8,000 breeds of the 11 species most commonly eaten by humans
- Breeds were uniquely adapted to local climate
- Many breeds are now extinct, or at risk due to
selection for only highest productivity

Question 12

Mitigating Biodiversity Loss

Answer 12

Protecting and connecting habitats
- Protecting important habitats by creating national parks, nature preserves, or preventing them from being developed
- Connecting fragmented habitats with wildlife corridors enables movement/breeding

Sustainable land use
- Urban growth boundaries, infill, and building up (not out) to reduce urban sprawl can preserve existing habitats
- Expanding parks, urban gardens, green roofs can provide habitat for many species
- Sustainable agriculture, lowering meat consumption can reduce ag. land needs, preventing hab. loss

Restoring lost habitats
- Replanting clear-cut forests
- Reestablishing prairies on old ag. fields or golf courses