The so‐called MSS (=Milieu souterrain superficiel) is composed of a network of small voids in screes covered by a soil layer. According to several authors, by providing an insulation layer from the outside, MSS microclimatic conditions are strictly comparable with that of other hypogean environments, such as caves. Spiders living in MSS have been poorly investigated. We designed an subterranean pitfall‐trap survey in order to: i) characterize spider assemblage living in MSS; ii) explore the occurrence of the different species in relation to depth; iii) compare the species inhabiting the MSS with species inhabiting the cave compartment. The study was conducted in two caves belonging to the Pugnetto hypogean area (Graian Alps, NW Italy). Several pitfall traps were placed in the Pugnetto caves, ranging from the cave entrance to the interior (approximately 500 m inside). The MSS habitat occurring around the caves was sampled with subterranean traps, capable of collecting fauna at a deepness of 0.40, 0.60 and 0.80 m. Moreover, in order to characterize the underground microclimate, we placed temperature and humidity dataloggers in correspondence of each trap. Traps were replaced once a month for one year. Over the year, we collected 17 spider species in the MSS and 8 in the caves. Troglophile (e.g. Nesticus eremita) and subterranean specialized species (e.g. Troglohyphantes bornensis) were collected in both environments. The higher diversity of species in the MSS was mainly related to the presence of trogloxene (occasional) species. Several individuals belonging to a possible new species of Troglohyphantes (Linyphiids), apparently exclusive of the MSS domain, were also collected. Regarding microclimate, the thermal variability at the surface seemed to moderately affect the microclimatic conditions of MSS, resulting in smoothed, but still present, daily and seasonal variations in temperature and humidity.
Comparison between spider assemblages inhabiting the cave and the associated MSS in the Pugnetto hypogean complex (NW Italy)
MAMMOLA, STEFANO;ISAIA, MARCO
2014-01-01
Abstract
The so‐called MSS (=Milieu souterrain superficiel) is composed of a network of small voids in screes covered by a soil layer. According to several authors, by providing an insulation layer from the outside, MSS microclimatic conditions are strictly comparable with that of other hypogean environments, such as caves. Spiders living in MSS have been poorly investigated. We designed an subterranean pitfall‐trap survey in order to: i) characterize spider assemblage living in MSS; ii) explore the occurrence of the different species in relation to depth; iii) compare the species inhabiting the MSS with species inhabiting the cave compartment. The study was conducted in two caves belonging to the Pugnetto hypogean area (Graian Alps, NW Italy). Several pitfall traps were placed in the Pugnetto caves, ranging from the cave entrance to the interior (approximately 500 m inside). The MSS habitat occurring around the caves was sampled with subterranean traps, capable of collecting fauna at a deepness of 0.40, 0.60 and 0.80 m. Moreover, in order to characterize the underground microclimate, we placed temperature and humidity dataloggers in correspondence of each trap. Traps were replaced once a month for one year. Over the year, we collected 17 spider species in the MSS and 8 in the caves. Troglophile (e.g. Nesticus eremita) and subterranean specialized species (e.g. Troglohyphantes bornensis) were collected in both environments. The higher diversity of species in the MSS was mainly related to the presence of trogloxene (occasional) species. Several individuals belonging to a possible new species of Troglohyphantes (Linyphiids), apparently exclusive of the MSS domain, were also collected. Regarding microclimate, the thermal variability at the surface seemed to moderately affect the microclimatic conditions of MSS, resulting in smoothed, but still present, daily and seasonal variations in temperature and humidity.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
