Big Bend Biosphere Reserve

Location:Texas, United States
IUCN Category:II
Area:815,561 acres (330,046 hectares)
Species:All  Endangered  Invasive
Website:View website
Climate:View Climate Data
Land Use:View Land Use Data
Köppen climate classification:BWh (Climate: arid; Precipitation: desert; Temperature: hot arid)

Ecoregions

Chihuahuan desert
Sierra Madre Oriental pine-oak forests

Soils

Link to Map
Protected Area Boundary
 AB
   
Share60 %20 %20 % 
Soil TypeCalcaric RegosolsHaplic YermosolsLithosolsEutric Regosols
Topsoil TextureMediumMediumMediumCoarse
Reference Depth100 cm100 cm10 cm100 cm
DrainageImperfectlyModerately wellImperfectlySomewhat excessive
Available Water Capacity50 m150 m15 mm100 m
Phase 1Lithic   
Topsoil Properties
Gravel17 %20 %26 %19 %
Sand43 %41 %43 %73 %
Silt35 %39 %34 %23 %
Clay22 %20 %23 %4 %
USDA TextureLoamLoamLoamSandy loam
Reference Bulk Density1.4 g/cm³1.41 g/cm³1.39 g/cm³1.7 g/cm³
Bulk Density1.4 g/cm³1.51 g/cm³1.3 g/cm³1.52 g/cm³
Organic Carbon0.77 %0.41 %1.4 %0.41 %
PH88.37.66
Clay Cation Exchange Capacity40 cmol kg⁻¹47 cmol kg⁻¹42 cmol kg⁻¹140 cmol kg⁻¹
Soil Cation Exchange Capacity17 cmol kg⁻¹8 cmol kg⁻¹15 cmol kg⁻¹14 cmol kg⁻¹
Base Saturation100 %100 %100 %80 %
Total Exchangeable Bases31.1 cmol kg⁻¹18.1 cmol kg⁻¹15.6 cmol kg⁻¹11.2 cmol kg⁻¹
Calcium Carbonate15 %1.5 %3.9 %0 %
Calcium Sulphate0 %0.1 %0 %0 %
Exchangeable Sodium2 %6 %4 %2 %
Electrical Conductivity0.3 dS m-11 dS m-10.1 dS m-10 dS m-1
Subsoil Properties
Gravel18 %27 % 19 %
Sand38 %38 % 73 %
Silt36 %40 % 23 %
Clay26 %22 % 4 %
USDA TextureLoamLoam Sandy loam
Reference Bulk Density1.36 g/cm³1.39 g/cm³ 1.7 g/cm³
Bulk Density1.52 g/cm³1.49 g/cm³ 1.53 g/cm³
Organic Carbon0.53 %0.22 % 0.15 %
PH8.18.3 6.4
Clay Cation Exchange Capacity50 cmol kg⁻¹42 cmol kg⁻¹ 140 cmol kg⁻¹
Soil Cation Exchange Capacity15 cmol kg⁻¹9 cmol kg⁻¹ 13 cmol kg⁻¹
Base Saturation100 %100 % 85 %
Total Exchangeable Bases41.1 cmol kg⁻¹26.8 cmol kg⁻¹ 11.1 cmol kg⁻¹
Calcium Carbonate15 %4.5 % 0.2 %
Calcium Sulphate0 %0.7 % 0.1 %
Exchangeable Sodium1 %5 % 3 %
Electrical Conductivity0.3 dS m-13.8 dS m-1 0.1 dS m-1
Soil data provided by FAO/IIASA/ISRIC/ISSCAS/JRC, 2012. Harmonized World Soil Database (version 1.2). FAO, Rome, Italy and IIASA, Laxenburg, Austria.
Köppen climate classification provided by Kottek, M., J. Grieser, C. Beck, B. Rudolf, and F. Rubel, 2006: World Map of Köppen-Geiger Climate Classification updated. Meteorol. Z., 15, 259-263