The karst landscape refers to a diversity and abundance of karst reliefs (lapiás, dolines, algares and caves) that are shaped by the action of rain, creating reliefs and very varied forms both on the surface and underground. These structures allow for the presence of very specific ecosystems where colonizing plant species, characteristic of rupicolous and/or fissured habitats, survive in situations of soil and/or water scarcity.

Given the karst nature of the entire Barrocal Algarvio, the territory of the Geopark includes a complex system of caves that are home to a large part of the Algarve's bat population, including important hibernation and breeding colonies, at national level, of the lesser mouse-eared bat (Myotis blythii) and a considerable population of the Moorish horseshoe bat (Rhinolophus mehelyi) and the hoary bat (Miniopterus schreibersii) during the breeding and hibernation seasons. These species have unfavorable conservation status, the first two being Critically Endangered (CR) and the third Vulnerable (Vu), all of which are protected under the Habitats Directive and the Bern and Bonn Conventions.

The caves in this area are also home to a rich community of cave-dwelling animals, relict species endemic to the Algarve with specific adaptations to underground life, such as the absence of pigmentation or organs of vision, including the giant Algarve pseudoscorpion (Titanobochica magna), the Algarve cave-dwelling dipluro (Litocampa mendesi) and the giant tisanuro (Squamatinia algharbica).

This territory also includes the only karst cavity in Portugal considered a “World Cave Biodiversity Hotspot”.