JD L7 Flashcards
Anthropocene
The current geological age, viewed as the period during which human activity has been the dominant influence on climate and the environment
Global environmental change addresses?
Large-scale chemical, biological, geological and physical perturbations of the earth’s surface, ocean, land surface and hydrologic cycle with special attention to time scales of decades to centuries to human-caused perturbations and their impacts on society
Biotic interactions in the anthropocene
- Biodiversity loss
- Invase species
- Climate change
Biodiversity loss
Reduction in abundance, extirpation, extinction.
Extirpation- local extinction
Principal drivers of biodiversity loss
- Habitat loss
- Overexploitation
What is habitat loss
The permanent conversion of former habitat to an area where that species can no longer exist.
How can habitat loss occur?
- Destruction
- Fragmentation
- Degradation
What is overexploitation
Depletion of numbers through harvesting of individuals
How does habitat loss impact biotic interactions?
By reducing species abundances and driving local extinctions, habitat loss can alter competitive interactions, predation, and mutualistic relationships between species
Overexploitation leads to what ecological phenomenon?
Trophic cascade
What is trophic cascade
It is an ecological phenomenon triggered by the addition or removal of top predators and involving reciprocal changes in the relative populations of predator and prey through a food chain, which often results in dramatic changes in ecosystem structure and nutrient cycling
Invasive alien species
An introduced species which becomes established in natural or semi-natural ecosystem or habit, is an agent of change and threatens native biological diversity.
Impact of invasive species
They can have significant environmental, economic and human health impacts
What is a fundamental niche?
The physiologically optimal range of conditions where a species can survive
What is the realized niche of an organism?
Where the species actually lives
Enemy release hypothesis
Invasive species, on introduction to a new region, experience a decrease in regulation by natural enemies resulting in a rapid increase in distribution and abundance
Impact of ornamental gardening
- Alters habitat, reduces diversity
- Winter dieback makes riparian areas vulnerable to erosion
- Can cause damage to property
Predator invasion success may be attributed to?
- Prey naivete
- Absence of anti-predator behavior between native and non- native species
What is prey naivete
Failure of prey to recognize predators as threat.
Climate change can result in changes in species phenology sometimes causing what?
Trophic mismatches
Climate induced range shifts can result in?
Spatial mismatches in the distribution of interacting species
Examples of spatial mismatches
Bark beetles encounter naive hosts at their expanding range edge increasing population growth
Competitive dominance
Climate change will favor species able to tolerate warmer and more variable climatic conditions resulting in a relative increase in their performance
How are competitive interactions altered?
By changes in dominance of plant and animal species
The invasiveness of introduced non-native species is regulated by what biotic interactions?
- Vacant niches
- Enemy release
- Prey naivete
