Population Ecology (W6) Flashcards
Ecological niche?
= involves an organism’s tolerances (conditions) & requirements (resources).
Eg of conditions? (3)
• Heat.
• Acidity.
• Windiness.
Egs of resources? (4)
• Food.
• Soil.
• Nutrients.
• Sunlight.
Niche dimensions?
= habitat factors.
Egs of niche dimensions? (2)
• Acidity.
• Salinity.
Habitat?
= the combination of resources & conditions that promote occupancy by individuals of a particular species.
Habitat attributes? (3)
• Species-specific (eg habitat for meerkats).
• Spatial locations associated with resources like food, water, shelter, security from predators/parasites.
• Serves a particular function (eg. feeding habitat).
Promoting factors?
= increase the likelihood of occupancy.
Restricting factors?
= decrease the likelihood of occupancy.
Egs of Promoting factors from House discussion? (3)
• Price.
• Space.
• Close to shops.
Egs of Restricting factors from House discussion? (3)
• Crime.
• Near a coal power plant.
• Neighbouring properties are dodgy.
Habitat use?
= pattern of individual locations with respect to habitat factors, which are linked to an individual’s movement.
What does habitat use depend on?
The ability of the individual to access the habitat.
Tool used when understanding an individual’s use of a habitat?
Home range (HR).
HR properties to know? (2)
• Overlap in HR between individuals.
• Spacing of HR/between HR.
What does overlap in HR between individuals tell us?
Tells us whether species are gregarious or territorial.
What does spacing of HR/between HR tell us?
Gives us spatial perspective on changes in the population abundance over time.
Lots of overlap of HR between individuals means…?
Gregarious individuals.
Eg of gregarious species?
Sable antelope.
No overlap of HR between individuals means…?
Territorial individuals.
Eg of territorial individuals?
Prides of lions.
Full landscape of HR means …? (2)
• Population is territorial.
• Population is at ED.
Still more room landscape means…?
Population is growing & not yet at a population density (middle of sigmoid graph).
What do we use to estimate HR?
Spatial field data.
Spatial field data attributes? (4)
• GPS collar used.
• Data are collected at intervals (daily, hourly).
• Variation in lengths of “steps” between locations.
• Most of an individual’s time is spent in a small fraction of the available area.
Why use a GPS collar?
Placed on animal to track its movement & location.
Downside of collecting data at intervals (daily, hourly)?
We only see a subset of where an individual occurs & not the full picture.
What does the variation in lengths of “steps” between locations tells us/help us with?
Gives us an idea of what an animal might be doing as it moves from one location to another.
“Most of an individual’s time is spent in a small fraction of the available area”, what does this mean/what can you deduce from this?
Animals appear to show preference for some patches over others.
Goals of estimating HR? (3)
• To characterize the overall pattern of use on the landscape.
• To measure the extent/size of the area over which individuals traverse as they do their life activities.
• To relate location & search paths to variables in the environment.
What information does relating location & search paths to variables in the environment provide? (2)
• Tells us what factors in the environment affect where we find locations & where steps occur.
• Gives us information about the biology of the species we are studying.
HR estimators? (3)
• Minimum convex polygon (MCP).
• Kernel method.
• Local Convex Hull (LoCoH).
HR method criteria for a good method? (2)
• Must give us HR size & location.
• Must give us utilization distribution (intensity of use).
MCP method attributes? (2)
• Easiest.
• Most common.
Importance of MCP? (2)
• Gives us extent/size of the HR.
• Gives us location of polygon (HR) using GPS.
Con of MCP?
Doesn’t provide utilization distribution.
Types of Kernel method estimators? (3)
• Bivariate kernel.
• Adaptive kernel.
• Brownian bridge kernel.
Bivariate kernel attributes? (3)
• Fits a 3D normal distribution around a set of points.
• X & Y coordinates measure extent of area used by the individual.
• Z coordinate measures intensity of use by individuals.
What do the X & Y coordinates of the Bivariate kernel method measure?
The extent of area used by the individual.
What do the Z coordinate of the Bivariate kernel method measure?
The intensity of use by individuals.