Ecology & Global Change Exam 3

Anthropogenic Stressors:

Human-caused pressures that increase mortality or limit reproduction

Extinction

loss of an entire species

Extirpation

loss of an entire population while the species persist somewhere else

Extinction Vortex 

positive feedback processes that increase extinction likelihood in small populations

Allee Effect

reduced pop. size/ density lower survival and reproduction rates 

Metapopulation

group of spatially separated populations connected through migration and recolonization

Lag effect

delay between environmental change and species 

Extinction debt

future extinctions caused by past or current events

Population Viability Analysis

predicts the probability of a population persisting over time based demographic parameters 

minimum viable population

threshold pop. size necessary to prevent extinction under defined conditions

Species distribution model

predicts species geographic range suitability based on environmental variables 

Sixth Mass Extinction

current rapid global extinction event caused by human activity

Intraspecific interactions

interaction within a species

Interspecific interactions

interaction btw diff. species

What are some Interspecific interactions?

predation, where a lion hunts a gazelle

competition, where owls and foxes both hunt rodents

mutualism, such as bees pollinating flowers and getting nectar

commensalism, where barnacles attach to a whale and get a place to live without affecting the whale

Obligate Interactions

type of interaction that is essential for survival or reproduction

Facultative Interaction

interaction that is beneficial but not required for survival 

Direct Interaction

one species directly effects another

Indirect interaction

effects mediated through other species or trophic pathways

Top-down effects

higher trophic levels regular lower levels

ex. predators control herbivores 

Bottom-up effects

resource or nutrient availability shapes higher trophic levels 

Trophic cascade

Ripple effects across trophic levels due to changes in one species

Coextinction

Loss of one species leads to loss of a dependent species

Trophic mismatch

Timing mismatch between consumers and their resources caused by environmental change

Invasive species

Non-native species that alter ecological function and can decrease native biodiversity

Ecosystem structure 

physical and biological components of an ecosystem

Ecosystem function

biological, physical, and chemical processes occurring within a ecosystem

Ecosystem services 

benefits the ecosystem provided to humans

ex. pollination, water purification

Biogeochemical cycles

movement of nutrients and energy through biotic and abiotic components 

Carbon cycle

1. photosynthesis + respiration

2. organic matter + waste

3. CO2 stored underground

4. CO2 produced by humans

Nitrogen cycle

1. nitrogen fixation (making nitrogen usable)

2. nitrification (processing of nitrogen compounds)

3. assimilation (absorption of plants and animals)

4. ammonification (decomposition of organic matter)

5. denitrification (return of nitrogen gas to the atmosphere)

Water cycle

1. evaporation

2. condensation

3. precipitation

4. collection

Positive feedback loop

amplifies change

ex. melting ice —> more global warming

Negative feedback loop

Counteracts change and stabilizes the system

Ecosystem collapse

Rapid, persistent loss of structure and function in an ecosystem

Tipping point

Threshold beyond which change becomes abrupt and dramatic

Ecosystem resilience

Ability to recover from disturbance while maintaining function and structure

Functional redundancy

Multiple species serve similar ecological roles, buffering against biodiversity loss

Connectivity

Movement of organisms or materials across landscapes that enables recovery

Conservation triage

Prioritizing limited conservation resources based on viability or importance

Fine-filter strategies

Conservation actions targeting individual species

Fine-filter strategies examples

protecting critical habitats like the natal ponds of a Tiger Salamander

managing old-growth forests to meet the needs of a species

Coarse-filter strategies

Conservation actions targeting ecosystems or landscapes

Coarse-filter strategies examples

managing forest ecosystems by mimicking natural disturbance patterns

In-situ conservation

Protecting species in their natural habitat.

Exit-situ conservation

Protecting species outside natural habitats (zoos, breeding programs)

Assisted Migration

Moving species to suitable habitats they cannot reach naturally

Assisted evolution

Accelerating adaptation via selective breeding or genetic modification

Reconciliation Ecology

Designing human landscapes to support biodiversity (e.g., green roofs, native plantings)

Adaptive

Iterative conservation approach that monitors outcomes and adjusts strategies accordingly

Delineate the key factors influencing the extent of future environmental impacts

Population growth, economic development, technological advancements, consumption patterns, and policy frameworks