Biogeography: soils, vegetation and protected natural areas
Domain 4 links parent material and climate to soil types, then to plant communities, and finally to the protection figures that conserve them.
Soils
- Distinguish zonal soils (climate-driven) from azonal soils (parent material, water table, slope).
- In Castilla y León: leptosols and regosols on slopes, cambisols widespread, calcisols and rendzina-like soils on limestone, luvisols on clayey campiñas, fluvisols on terraces, histosols in wetlands.
- Siliceous west (granite, slate): acidic, nutrient-poor, rankers and podzols. Basic east and south (limestone): basic, clayey, carbonate-rich.
Vegetation series
- Atlantic fringe (north and north-west, above about 800 mm): beech, pedunculate oak, birch, chestnut and meadows.
- Mediterranean Meseta: holm oak (encina), Portuguese oak (quejigo), juniper and savin, pine woods (Pinus pinaster on siliceous ground; P. sylvestris and P. nigra in the mountains), with thyme, rosemary and retama scrub.
- Riparian corridors: alder, poplar, willow, ash and elm.
- High mountain: piornal (Genista), broom and pastures above the tree line in Gredos, Picos and Urbión.
- Dehesa: a managed holm-oak pasture system, not climax forest.
Protection
- Red Natura 2000 combines ZEC (Habitats Directive) and ZEPA (Birds Directive).
- Picos de Europa, declared in 1918, was Spain's first national park and is shared with Asturias and Cantabria.
- Regional figures include Sierra de Gredos, Cañón del Río Lobos, Hoces del Duratón, Hoces del Riaza, Arribes del Duero, Fuentes Carrionas y Fuente Cobre, Sabinares del Arlanza and the Villafáfila wetlands.
Worked example
Two slopes at 1 100 m: slope A on granite with pH 5.2 and 900 mm of rainfall; slope B on limestone with pH 7.9 and 500 mm. Reasoning chain: parent material controls pH and water retention, pH controls nutrient availability, rainfall controls the water balance. A supports acidophilous woodland (Pinus pinaster, oak) with heather; B supports holm oak or quejigo with calcicole scrub. A south-facing aspect would shift both towards more xeric communities.
Traps
- Describing the dehesa as natural climax vegetation.
- Confusing encina (Quercus ilex) with quejigo (Quercus faginea).
- Extending Atlantic vegetation to the whole region.
- Forgetting azonal soils such as fluvisols and histosols.
- Using ZEC and ZEPA criteria interchangeably.