species distribution modelling Flashcards
what are the three dependent variables for distribution modelling?
occupancy, abundance and species richness
what does resource selection function do?
identify areas within landscapes that are (frequently) occupied by a population of a species, and assuming they are there because of resources
what type of data is a species occupying a location or not?
Binary
in resourse selection function, how to determine presence?
direct and indirect observations
in resourse selection function, how to determine absence?
direct and indirect observations, and random points where the species have not been seen
How to visually compare distribution selected vs available locations in resource selection function?
in graphs with available and selected, if the selected part follows the available, or is very broad there is no selection. if it’s small there is.
what’s a simple way of quantifying habitat use?
Resource seleciton ratios
how to calculate resource selection ratios?
Proportion used= Number of observations in habitat type i / total number of observations
Proportion available= area habitat type i / total area.
Then you can calculate the resource selection rate (Wi) = prop. Used / Prop. Available
when is there selection or not in Wi?
If Wi = 1, no selection
If Wi = >1, selection
If Wi = <1. avoidance
how to really explain presence and absence?
Generalized linear model (GLM)
what’s the principle of maximun entropy?
the assumption that every location where species has been observed has the same probability of presence.
what’s AUC?
measure of model fit
when is the AUC good?
AUC= 0.5 means a straight line, and random chance. rule of thumb >0.7 then it’s okay.
when do you use MaxEnt?
with presence only data
what is Wi?
resource selection ratio
