Variability of A Subterranean Prey-Predator Community in Space and Time

Abstract

Subterranean habitats are characterized by buffered climatic conditions in comparison to contiguous surface environments and, in general, subterranean biological communities are considered to be relatively constant. However, although several studies have described the seasonal variation of subterranean communities, few analyzed their variability over successive years. The present research was conducted inside an artificial cave during seven successive summers, from 2013 to 2019. The parietal faunal community was sampled at regular intervals from outside to 21 m deep inside the cave. The community top predator is the cave salamander Speleomantes strinatii, while invertebrates, mainly adult flies, make up the rest of the faunal assemblage. Our findings indicate that the taxonomic composition and the spatial distribution of this community remained relatively constant over the seven-year study period, supporting previous findings. However, different environmental factors were shaping the distribution of predators and prey along the cave. Invertebrates were mainly affected by the illuminance, while salamanders were influenced by both illuminance and distance from the cave’s entrance. The inter-annual spatial distribution of the salamander population was highly repeatable and age specific, confirming a gradual shift towards the deeper parts of the cave with an increasing age. In general, the spatial distribution along the cave of this prey-predator system remained relatively constant during the seven-year study, suggesting that strong selective constraints were in action, even in this relatively recent subterranean ecosystem.

Size-related boldness is not altered by stomach flushing in a terrestrial salamander

“…In any case, although a behavioural switch from a relatively shy to a bolder behaviour could be hypothesised during development, the behaviour of the young in their first and second year was not tested, and therefore further experiments should be performed. Body size in amphibians is correlated with age, suggesting that in cave salamanders the observed differences in behaviour may be largely driven by development stage, as already described in the case of spatial distribution patterns (Salvidio and Pastorino, 2002;Salvidio et al, 2020).…”

“…All experiments were performed inside the Biospeleological Station of S. Bartolomeo di Besolagno, an artificial underground tunnel excavated in the municipality of Savignone (province of Genova) and used as an air shelter during WWII (Salvidio et al, 1994). This artificial cave has been naturally colonized by cave salamanders at least since 1972 (Pastorino and Pedemonte, 1974), and the abundance and demographic structure of the resident population has been annually analysed by temporary removal sampling since 1996 (Salvidio and Pastorino, 2002;Salvidio et al, 2020). The Station, managed by the Gruppo Speleologico Ligure "A. Issel", was closed by an iron gate in 1987 and, therefore, accessible only to researchers.…”

“…Animals and tools were handled with nitrile gloves, paper sheets were changed after each trail, and plastic cups were used only once. Mature males possess a swollen mental gland (Lanza, 2007); individuals lacking the mental gland and with SVL 57 mm were considered mature females, while those < 57 mm in SVL and lacking the mental gland were considered immatures (Salvidio and Pastorino, 2002;Salvidio et al, 2020).…”

Сarbon fluxes intensity from substrates and phototrophic consortiums of the photic zones in Montenegro caves

“…Typically soil respiration demonstrates maximum at intermediate soil moisture values, and decreasing under drier or wetter conditions (Davidson & Janssens, 2006;Moyano et al, 2013). Due to the stable microclimate parameters (Salvidio et al, 2020) conditions of a stable balance between humidity and temperature of air and soil are achieved in caves. This ensures the maximum moisture content of the substrates at a stable underground temperature.…”

Do Salamanders Limit the Abundance of Groundwater Invertebrates in Subterranean Habitats?

“…As an example, they can help us understand the dynamics of novel habitat colonizations and provide useful insights to understand the relative role of phenotypic plasticity and local adaptations [22]. Moreover, as they can reach high abundances and show well defined patterns (i.e., seasonal, ecological) of cave exploitations, they can exert important roles on the community inhabiting the surrounding of the cave entrance and the twilight zone [23,24].…”