The Scientific World Journal / 2012 / Article / Tab 1

Research Article

Applying Fuzzy Logic to Comparative Distribution Modelling: A Case Study with Two Sympatric Amphibians

Table 1

Factors and their related variables used to model the distributions of Bufo bufo, Epidalea calamita, and the combined presences of the two species. Sources: (1)U. S. Geological Survey (1996); (2)Font (1983, 2000); (3)I.G.N. (1999); data on the number of inhabitants of urban centres taken from Enciclopédia Universal ( for Portugal and from the Instituto Nacional de Estadística ( for Spain, both in 1999.


TopographyMean altitude (m)(1)alti
Mean slope (degrees) (calculated from Alti)slop

Water availabilityMean annual precipitation (mm)(2)prec
Mean relative air humidity in January at 07:00 hours (%)(2)hjan
Mean relative air humidity in July at 07:00 hours (%)(2)hjul

Environmental energyMean annual insolation (hours/year)(2)inso
Mean annual solar radiation (kwh/m2/day)(2)srad
Mean temperature in January (°C)(2)tjan
Mean temperature in July (°C)(2)tjul
Mean annual temperature (°C)(2)temp
Mean annual number of frost days (min. temperature ≤ 0°C)(2)dfro
Mean annual potential evapotranspiration (mm)(2)pet

ProductivityMean annual actual evapotranspiration (mm) (=min [PET, Prec])aet

Environmental disturbanceMaximum precipitation in 24 hours (mm)(2)mp24
Relative maximum precipitation (=MP24/Prec)rmp

Climatic variabilityMean annual number of days with precipitation ≥ 0,1 mm(2)dpre
Annual temperature range (°C) (=TJul-TJan)tran
Annual relative air humidity range (%) (= | H J a n - H J u l | )hran

Human activityDistance to a highway (km)(3)dhi
Distance to a town with more than 100,000 inhabitants (km)(3)u100
Distance to a town with more than 500,000 inhabitants (km)(3)u500

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