Threats to biodiversity

Question 1

What are the threats to biodiversity?

Answer 1

Habitat disruption
Climate change
Over-exploitation
Invasive alien species
Infectious disease

Question 2

Habitat destruction

Answer 2

Urban, industrial, agricultural
Forest clearance, related to reduction in precipitation
Fragmentation
Reduced population sizes

Question 3

Habitat degradation

Answer 3

Pollution
Pesticides, fertiliser, acid rain

Question 4

Habitat disturbance -

Answer 4

Subset of population affected
Minor individual effects
Leads to cumulative change

Question 5

Noenicitinoid pesticide use

Answer 5

Neurotoxin for invertebrates
Systemic treatment, water soluble so can move in soil
Initially used as a seed dressing
Environmentally persistent and accumulates
Experimental exposures - bumble bee nests found to be significantly smaller
85% reduction in production of new queens

Question 6

Over-exploitation

Answer 6

Unsustainable harvest leads to extinction; mega-fauna, cetaceans and other fisheries
Valued for food
Also as medicine for aesthetic reasons, industrial materials and recreational harvesting
Economically - value increases as rarity increases, resource seen as more desirable

Question 7

Effect of Climate change on ecosystems

Answer 7

In the individual/population - phenotypic plasticity and evolution
Migration and range shifts change
In communities, species level selection, turn over of species
Current vs immigrant species

Question 8

Adaptive phenotypic plasticity

Answer 8

Eg parus major
When weather is warm, eggs are laid sooner
The ability of an organism to alter its phenotype (physical characteristics) in response to environmental changes

Question 9

Mechanisms of decline in small populations

Answer 9

Chance effects and population size
Demographic uncertainty
Genetic problems; inbreeding or impoverishment, inbreeding potential results

Question 10

Jennifer owen

Answer 10

Wildlife garden
30 year study
2673 species, 4 new to science
Around 400 mammal species discovered since 1993

Question 11

Where is biodiversity found?

Answer 11

Noted that if a larger area is sampled the more species that are encountered

Question 12

Methods to estimate global species richness

Answer 12

Macro-ecology patterns, latitudinal gradients, body-size frequency
Diversity ratios, ratios in taxon number, host-specificity

Question 13

Extinction and endemism

Answer 13

Area and persistence
Small geographic ranges dominate
Small ranges and scarcity