Search for notes by fellow students, in your own course and all over the country.
Browse our notes for titles which look like what you need, you can preview any of the notes via a sample of the contents. After you're happy these are the notes you're after simply pop them into your shopping cart.
Title: Animal distributions and disperal
Description: These notes cover how animals use the landscape, from how they are distributed (where they are) to how they move across the landscape (disperse). These notes were used for Wildlife Management at American Public University.
Description: These notes cover how animals use the landscape, from how they are distributed (where they are) to how they move across the landscape (disperse). These notes were used for Wildlife Management at American Public University.
Document Preview
Extracts from the notes are below, to see the PDF you'll receive please use the links above
Introduction
Fine-scale patterns = dispersion
Large-scale patterns = distribution
Dispersal – movement from place of birth to place of reproduction
Migration – movement between summer and winter range
Local movement – movement within a home range
Dispersion is the pattern of spatial distribution taken up by the animals of an area
Distribution is the area occupied by a population or species
Dispersal
An action performed by an individual
Presaturation dispersal involves juveniles leaving their natal range even when density of the
population is low
Saturation dispersal is when animals disperse because a population reaches a threshold
determined by food limitation (density-dependent)
Patterns of dispersal related to type of mating system
o Females concerned with gaining resources and are therefore philopatric (remain at natal
range)
o Males concerned with gaining mates
o Both sexes disperse in monogamous species
Dispersal categories
o Competition for mates
o Avoidance of inbreeding
o Competition for resources
Dispersers have lower survival than counterparts
Dispersion
Dispersion can be random, clumped, or spaced
o Most common is clumped (aka contagious)
o Determined by dividing an area into quadrats and the frequency distribution of animals
per quadrat is recorded
...
Some animals can increase body temp
before they start panting and others conserve water by concentrating urine and reducing output
Range limited by day length and seasonality – photoperiod and breeding in birds (proximate
factor – immediate factor affecting an animal), triggers conception and result in production of
young during optimum conditions (ultimate factors – underlying selection pressure)
In variable environemnts (tropics, arid) animals respond to current conditions
Lactation – African ungulates put on fat prior to giving birth in the wet season and use fat stores
to meet energy demands when they are highest for lactation (Ojasti 1983, Sinclair 1983) –
therefore nutrition becomes the proximate and ultimate factor indeterming the timing of births
Biotic limiting factors – interspecific competition (arctic and red foxes)
Distribution, Abundance, and Range Collapse
Rapoport’s rule: the latitudinal extent of a species’ range increases towards the poles – general
pattern is modfieid by species richness, rainfall, vegetation, and land surface
Species populations tend to collapse from the center and leave peripheral populations that
provide a refuge and represent genetic and morphological varieties that differ from the central
population
Species Reintroductions or Invasions
Random walk model – assume hypothetical animal can only move forwards, backwards, or
sideways one step at a time and that each of these events is as probable as the other – then
sample randomly from a uniform probability distribution (good null models)
Can be extrapolated to groups of individuals – expansion is fast at first, but slows over time
because forward steps are counterbalanced by backward steps
Title: Animal distributions and disperal
Description: These notes cover how animals use the landscape, from how they are distributed (where they are) to how they move across the landscape (disperse). These notes were used for Wildlife Management at American Public University.
Description: These notes cover how animals use the landscape, from how they are distributed (where they are) to how they move across the landscape (disperse). These notes were used for Wildlife Management at American Public University.