Beyond Barren Land: Establishing Gypsum Botanical Gardens as a Successful Tool for Conservation and Ecosystem Restoration

Abstract

Modern botanical gardens are essential for conservation, research, education, and recreation. However, recreating habitats with extreme edaphic conditions, such as the Iberian gypsum steppes (priority habitat 1520), poses a significant challenge due to the severe physicochemical constraints of gypsisols. This work aimed to present and evaluate a biomimetic protocol for establishing two gypsum botanical gardens in the southeast Iberian Peninsula, one on a university campus and one at a mining concession, to fulfil all four prototypical functions. The design was biomimetic, replicating the floristic (Gypsophiletalia scrublands) and edaphic characteristics of natural gypsum areas. Crucially, gypsum-milling waste (fines) from the mining operation was repurposed as the main substrate to create the artificial gypsisols. Physicochemical analyses confirmed this strategy effectively replicated the key chemical properties of natural gypsisols, including high CaSO₄ concentration, pH, and electrical conductivity, although the artificial soils displayed the low carbon and nitrogen content typical of disturbed gypsum soils. The gardens successfully fulfilled their conservation role by maintaining populations of endemic and threatened gypsophilous species, which flowered and set fruit. The industrial garden validated a research function by serving as a platform for the successful translocation of threatened Narcissus tortifolius bulbs. This project validates a replicable, biomimetic technical protocol that transforms a mining residue into a functional substrate for conservation. The dual model (academic/industrial) maximizes the botanical garden’s functions, offering an effective and highly visible strategy for conserving gypsum biodiversity and countering the social undervaluation of these extreme ecosystems.