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Table 2 Independent variables selected by the boosted general additive model (boosted GAM) for the full area and polygon area models

From: Environmental and anthropogenic factors affecting the probability of occurrence of Oncomegas wageneri (Cestoda: Trypanorhyncha) in the southern Gulf of Mexico

  Independent variables Units Full area Polygon area
  Fr (%) Fr(%)
1 bspatial (Lon, Lat) DD 1.45 18.90
2 bbs (Total depth, S) m - 4.80
3 bbs (Temperature, W) °C 0.09 5.40
4 bbs (Salinity, W) UPS 0.13 0.60
5 bbs (Oxygen, W) (mg/L) 0.17 5.00
6 bbs (Alkalinity, W) meq/l 0.13 2.10
7 bbs (CO2, W) mmol/l 0.13 2.10
8 bbs (Nitrate, W) μMolar 0.21 3.00
9 bbs (Phosphate, W) μMolar 0.09 0.70
10 bbs (Silicate, W) μMolar - 1.10
11 bbs(Sigma T, W) Kg/m3 0.30 -
12 bbs(Sand, S) % - 0.50
13 bbs (Silt, S) % - 1.10
14 bbs (Clay, S) % 0.04 -
15 bbs (Phosporus, S) micromol/g 0.04 0.60
16 bbs (Nitrogen, S) micromol/g - 1.30
17 bbs (PAHL, S) μg/g 0.47 5.70
18 bbs (PAHH, S) μg/g 94.70 6.90
19 bbs (Aliphatic PAHs, S) μg/g - 0.60
20 bbs (PCNM2) DD 0.30 24.00
21 bbs (PCNM21) DD 0.47 3.70
22 bbs (PCNM58) DD 0.68 11.90
  1. Fr (%) is the frequency at which each variable is selected during the bootstrapping, and used as proxy of the importance of each of the variables (expressed as percentage) within the model. bbs = base-learner based on B-splines, bspatial = spatial base-learner on geographical coordinates. W = water, S = sediment; PAHL and PAHH are polyaromatic hydrocarbons of low and high molecular weight respectively; PCNM2, PCNM21 and PCNM58 are the spatial variables of the principal coordinates of neighbour matrices (PCNM) analysis, acting at 2, 21 and 58 km respectively