The Hospital del Obispo is a nava or flat area located at an altitude of 1000 m within the huge Ibor-Guadalupe anticline. It represents a valley raised above other nearby valleys and located on shales between the quartzite elevations of the Sierra del Rullo (Cancho del Ataque) and the Sierra del Hospital (Risco Carbonero).
The nava of the Hospital de Obispo has a gentle longitudinal profile with a less steep topographical slope than that of the other valleys drained by the streams of the area. As drainage is slow owing to this gentle slope, the rainwater floods the clayey and muddy sediments to form small pools known as “bohonales“, “quagmires”, or “trampales” where the peat bogs form.
Peat is an organic non compact material that is rich in carbon and water and that forms owing to the decomposition of plant material, generally mosses, under anaerobic conditions (a very low oxygen concentration). This constitutes an acid environment that excludes the presence of the bacteria and fungi that nitrify more fertile soils. It is for this reason that it becomes mineralised with a high carbon concentration. As this mineralisation process advances the peat slowly darkens from its initial light grey-brown colour and spongy appearance. The process is a slow one; the peat increases in volume but a few millimetres per year. Peat bogs contain materials from thousands of years ago that can be dated.
The vegetation of peat bogs is adapted to the scarcity of nutrients and endemic plant species may be present. In the trampales of the Hospital del Obispo Drosera rotundifolia (popularly known as “Rocío del Sol” or sun dew) can be found. This insectivorous plant makes up for the lack of soil nutrients by its ability to digest small insects that are trapped by the sticky secretions of the hairy leaves.
