So it is necessary that habitat suitability of Otis tarda will be modeled using the modern methods and technologies such as ENFA, GIS and remote sensing to determine the most important effective parameters on distribution and habitat mapping of this bird as a very valuable, rare and endangered one.
ENFA summarizes environmental variables into a few uncorrelated and standardized factors.
To comply with the statistical requirements of the ENFA method, if the correlation between two variables is more than 85%, one of the variables must be omitted from analyses.
Following Hirzel & Arlettaz (2003), the distance geometric mean algorithm in ENFA was used to predict habitat suitability across the study area.
To evaluate reserve design and identify potential sites for future monitoring of giant pandas, we overlaid the ENFA distribution model with the existing reserve zoning and the tourist areas proposed by the Tangjiahe Nature Reserve administration.
ENFA needs two types of data to calculate habitat suitability: a map of locations where the species has been detected and a set of quantitative raster maps describing the environment as used by the species under investigation.
altitude, slope and aspect) were quantitative and used directly in the ENFA model, but habitat structure, human impact and prey factors were qualitative and were transformed into frequency and distance variables before calculation (Hirzel et al.
Cuatro factores que permitieron explicar el 83% de la variabilidad total en las celdas con datos de presencia fueron seleccionados por ENFA.
La utilizacion de ENFA (Calenge y Basille, 2008) y la eleccion de variables por medio de regresiones por pasos que utilizan datos de presencia y ausencia permiten acercarse mejor a este objetivo.
TABLE 3 ENFA
analysis of eco-geographic variables for M.
In order to gather presence/absence data as input for the incidence function model, 117 patches obtained by the ENFA, covering a total of 9,862.
ENFA is a method that makes this possible with limited knowledge of the species ecology and a reasonable effort in field.