Lecture 20: Ecosystems: Aquatic nutrient regeneration & landscape ecology Flashcards
In aquatic systems, biochemical __________________ (all takes place in water)
processes are the same as on land
Main difference is that in aquatic systems, _________________ and __________________ sediment deposits.
- organic material sinks
- nutrients get stored in deep-water
Most nutrient regeneration in aquatic systems occurs in sediment deposits, but it is ____________ than regeneration in the soil of terrestrial systems
much slower
Aquatic sediment and terrestrial soils are _______________, but their roles in nutrient regeneration are _________________.
- superficially similar
- different in 2 key ways
differences in aquatic sediment and terrestrial soils
- Distance between regeneration and autotrophs
- Decomposition conditions
terrestrial soils - Distance between regeneration and autotrophs
Regeneration in soil takes place very close to the roots of plants.
aquatic sedimentation - distance between regeneration and autotrophs
Aquatic plants and algae inhabit the top (photic) water layers, far from nutrient regeneration in deep sediment.
terrestrial soils - decomposition conditions
Decomposition is aerobic and relatively quick in terrestrial soils.
aquatic sediment - decomposition conditions
- Decomposition is typically anaerobic in aquatic sediment
- The lack of oxygen slows the biochemical processes of regeneration.
_________________ when sediment is _____ from upper water layers, or if sediment nutrients are actively _____________.
- Productivity is only high
- not far
- redistributed
Primary _______________ in areas with strong _______________, providing active nutrient redistribution.
- productivity is also high
- upwelling currents
define landscape ecology
The study of the composition and spatial arrangement of habitats, both natural and anthropogenic, and how this influences ecological systems at all scales
how is landscape ecology a key link to
understanding global biodiversity
it has a major impact on biodiversity at regional and global scales
landscape ecology can be a discipline that bridges what
- ecosystems and the biosphere-level processes and patterns
- like global biodiversity
“Landscapes” can be thought of as a collection of___________________________________.
interacting habitat types within or across ecosystems
Landscapes are shaped by _____________, and ____________________.
- past and present
- natural and anthropogenic events
________________________________________, have changed rock and soil distribution, dramatically changed topology, and altered the size, shape and interactions between bodies of water
Volcanic eruptions, glacier movement, and continental drift
The long lasting influences of historical processes on present-day ecological processes are know as ____________ , and they can be natural or human legacy effects.
legacy effects
Legacy effects — the example of eskers
- When glaciers go away, you get really flat land
- Rivers are between glaciers and as the river flows, the sediment builds up
- When the glacier goes away – there is a small ‘mountain’ of sediment
Modern influences on landscapes
- Hurricanes
- Tornadoes
- Floods
- Mudslides
- Fires
All modern influences on landscapes cause _________________ and cause major ____________________________ that influence biodiversity
- major redistribution of nutrients
- changes to landscape structure and functions
Small-scale influences on landscapes - human settlements
- Human nutrient inputs and management practices increases plant species richness patterns and changes plant community structure
- closer to the settlement = more nutrients = more species richness
Large-scale modern human influences on landscapes
- Land conversion for settlement and farming.
- Vegetation changes from management and introduction.
- More frequent and more severe natural landscape-changing processes because they are occurring in an anthropogenic landscape
Large-scale modern human influences on landscapes - anthropogenic landscape
- widespread flooding
- widespread landslides
- widespread fires
- frequent and severe hurricanes and tornadoes (or at least more impactful aftermaths of these events)
Large-scale modern human influences on landscapes - widespread flooding
due to the alteration of natural vegetation and land barriers
Large-scale modern human influences on landscapes - widespread landslides
due to alteration of water movement, soil structure, and vegetation cover
Large-scale modern human influences on landscapes - widespread fires
due to changes in water use, land cover, and more sources of fire
Quantifying human impacts on landscapes
- remote sensing
- Global positioning systems (GPS)
- Geographic information systems (GIS)
Quantifying human impacts on landscapes - Remote sensing
- Airplane or satellite imaging of landscapes
- Not limited to normal photographs
Quantifying human impacts on landscapes - Global positioning systems (GPS)
Detailed mapping of land shape and surface topology, as well as tracking of organisms as they move through the landscape
Quantifying human impacts on landscapes - Geographic information systems (GIS)
GIS software allows for the layering of diverse datasets of geographic information to identify novel landscape-level interactions
Satellite imaging - remote sensing
- Allows us to accurately quantify and track landscape cover through time
- Visible spectrum of light: hard to get information from
- Near-infrared (reflected by plants): easier to see, red represents the vegetation
What does GPS tracking of domestic cats reveal in an urban/natural landscape mosaic?
Extensive use of any intact natural habitat for hunting wild species.
What are the consequences of a domestic animal hunting wild species within the urban/natural landscape?
- Domestic cats kill/eat birds in high numbers at the urban/natural interface of the landscape mosaic
- Documented examples of eating urban/suburban bird populations to local extinction
define habitat fragmentation
Division of a large contiguous area of habitat into several smaller habitat patches by human or natural events
what can fragmentation do
divide populations, alter the balance of communities, and disrupt ecosystem processes
5 main effects of fragmentation
- Reduction in total amount of habitat.
- Increase in number of habitat patches.
- Decrease in size of the average habitat patch.
- Increase in patch isolation.
- Increase the amount of edge habitat.
Research focuses on the relative impacts of the ____________________________.
five main effects of fragmentation
- Habitat Area: species survival and total habitat size
Larger areas of habitat support more species — species-area relationship.
2, 3, 4. Patches: Fragmentation often makes patches act like isolated areas of habitat — no/limited meta population dynamics
- Large predators went extinct due to isolation on islands because there is no dispersal between islands
- Herbivore populations exploded (especially leaf-cutting ants), and vegetation changes, with greatest effects on smallest islands
Some species ________ from fragmentation and increase in abundance.
benefit
___________________ from fragmentation are typically those that are _____________ the transitional zones between habitats (________) or _____________________ — known as _____________.
- Species that benefit
- specialized for
- ecotones
- early succession
- edge specialists
Fragmentation drives ________, and thus __________________ for edge specialists.
- more edge
- increases the useable habitat
__________________ alone can dramatically __________________, community composition, and ecosystem dynamics
- Increase in edge habitat
- alter species interactions
Small patches disproportionately impact what populations
- predator population bc they larger and require more space
- this then shifting food web and biomass pyramids
what population grows due to lack of predators (relaxed top-down control) and fragmentation
Populations of smaller edge species
why are edge species considered “pests”
they are often well-adapted to handle human modifications
____________ of the white-footed mouse has ___________, due to use of edge habitats and loss of predators and competitors.
- Abundance
- increased
White-footed mice are a _____________ for the Lyme disease bacterium and help _____________________ that are the vectors of the ____________ bacterium.
- reservoir species
- disperse the ticks
- Lyme disease
Landscape ecology approach on Lyme disease and edge species
- Smaller fragments represent dramatically increased opportunity for infection.
- Smaller fragments also typically mean higher likelihood of human activity and contact with infection.
