New insights on the ecology of underground ecosystems toward a sustainable management strategy

Underground cavities represent some of the less explored places on the planet (Lee et al., 2012). In fact, excluding the known carbonate dissolution/precipitation processes, leading to the formation of holes in the host rock, as well as speleothems, little is known about the ecology of these fascinating and enigmatic ecosystems. In spite of this, caves are generally object of tourist adaptations, which can activate an irreversible impairment of the biogeochemical equilibria, whose load, until now, is not estimated accurately, due to the scanty information in this regard (Chiesi and Badino, 2008). The anthropogenic effects on the air compartment represent the most indiscernible and not immediately recognizable alteration, just thinking to the heat or breathing produced by human body, influencing the natural temperature, relative humidity and CO2 concentrations. Moreover, visitors can be carriers of inorganic and organic matter (dust, hair, bacteria, seeds…) constituting an important energy input, as well as a trophic source, in the cave oligotrophic ecosystem, affecting its natural energy regime (Russell and MacLean, 2008; Jurado et al., 2008; Smith et al., 2013; Bruno et al., 2014). These factors are able to influence the reactions at the interface between the atmosphere and the other compartments (lithosphere, hydrosphere and biota), fundamental in controlling the ecosystem processes, that ensure the functioning of the whole underground ecosystem (Pulido-Bosch et al., 1997; Milanolo and Gabrovšek, 2009; de Freitas, 2010; Lang et al., 2015a; Lang et al., 2015b; Howarth, 2019). Hence, the necessity to develop new, sturdy and low-cost tools, including also sensors for data acquisition and modelling applications (Bugmann et al., 2000; Schmolke et al., 2010), to monitor and assess continuously cave atmosphere, providing to the authority valid and efficient devices helping them in the sustainable management. [preface edited by Author]