Global change biology Flashcards
Human influences around globe
habitat loss, habitat fragmentation, species exploitation, movement of species, changing nutrient cycles, climate change
Habitate degradation
changes that reduce quality of habitat for many species
Habitat fragmentation
breaking up of once continuous habitat into series of patches
Invasive species
species introduced from outside their native range, rapidly increase in population size
Overexploitation
fishing or otherwise getting food from a natural system at unsustainable rate
Humans have altered __ and __ cycle
C and N
(N cycle even more altered!)
How have humans altered N cycle?
N2 fixation by humans exceeds natural rate
Applying fertilizers
Growing N fixing crops
Flooding field increases N2 fixation
Consequences of increasing fertilizaiton
Eutrophication: agricultural run off leads to high nutrient loads in aquatic systems
Effects in changes in land
risk to biodiversity
Ex. deforestation, forest fragmentation and edge effects
agriculture expansion
grassland biome largely converted to agriculture
Urbanization
replace natural ecosystems with surfaces (roads and buildings)
increasing surface temp
Desertification in arid regions
Overgrazing
Deforestation
3 major ways to influence radiation balance of earth
- change incoming solar radiation
- change albedo/reflectivity
- melting ice, deforestation, roads and buildings, soot and dust on ice - change how much long wave radiation goes back towards space (increase greenhouse effect)
Evidence that CO2 increase is human induced
Begins with start of industrial revolution and dips correspond to human history (wars and great depression)
Isotopic ratio corresponds to fossil fuels
