title: Ecology and sampling techniques of an understudied subterranean habitat: the Milieu Souterrain Superficiel (MSS).
abstract: The term Milieu Souterrain Superficiel (MSS) has been used since the early 1980s in subterranean biology to categorize an array of different hypogean habitats. In general terms, a MSS habitat represents the underground network of empty air-filled voids and cracks developing within multiple layers of rock fragments. Its origins can be diverse and is generally covered by topsoil. The MSS habitat is often connected both with the deep hypogean domain-caves and deep rock cracks-and the superficial soil horizon. A MSS is usually characterized by peculiar microclimatic conditions, and it can harbor specialized hypogean, endogean, and surface-dwelling species. In light of the many interpretations given by different authors, we reviewed 235 papers regarding the MSS in order to provide a state-of-the-art description of these habitats and facilitate their study. We have briefly described the different types of MSS mentioned in the scientific literature (alluvial, bedrock, colluvial, volcanic, and other types) and synthesized the advances in the study of the physical and ecological factors affecting this habitat-i.e., microclimate, energy flows, animal communities, and trophic interactions. We finally described and reviewed the available sampling methods used to investigate MSS fauna.
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina, 13-10123, Torino, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Mammola
authors.affiliation: Settore Fitosanitario Regionale, Environment Park, Palazzina A2, Via Livorno, 60-10144, Torino, Italy.
authors.forename: Pier Mauro
authors.initials: PM
authors.lastname: Giachino
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina, 13-10123, Torino, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Piano
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina, 13-10123, Torino, Italy.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Jones
authors.affiliation: Department of Physics, University of Torino, Via Pietro Giuria 1, 10125, Torino, Italy.
authors.forename: Marcel
authors.initials: M
authors.lastname: Barberis
authors.affiliation: Department of Physics, University of Torino, Via Pietro Giuria 1, 10125, Torino, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Badino
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina, 13-10123, Torino, Italy. marco.isaia@unito.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Isaia
mesh_terms: D000818:Animals; D004463:Ecology / Q000379:methods* / Q000592:standards* / Q000706:statistics & numerical data; D017753:Ecosystem; D012987:Soil
chemical_list: D012987:Soil
keywords: Arthropods; Cave ecology; Mesovoid shallow substratum; Superficial subterranean habitat; Troglobionts; Upper hypogean zone