Biodiversity Data Journal :
Data Paper (Biosciences)
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Corresponding author: Enrico Lunghi (enrico.arti@gmail.com), Yahui Zhao (zhaoyh@ioz.ac.cn)
Academic editor: Pedro Cardoso
Received: 20 Nov 2019 | Accepted: 16 Dec 2019 | Published: 03 Feb 2020
© 2020 Enrico Lunghi, Claudia Corti, Manuela Mulargia, Yahui Zhao, Raoul Manenti, Gentile Francesco Ficetola, Michael Veith
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Lunghi E, Corti C, Mulargia M, Zhao Y, Manenti R, Ficetola GF, Veith M (2020) Cave morphology, microclimate and abundance of five cave predators from the Monte Albo (Sardinia, Italy). Biodiversity Data Journal 8: e48623. https://doi.org/10.3897/BDJ.8.e48623
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Systematic data collection on species and their exploited environments is of key importance for conservation studies. Within the less-known environments, the subterranean ones are neither easy to be studied, nor to be explored. Subterranean environments house a wide number of specialised organisms, many of which show high sensitivity to habitat alteration. Despite the undeniable importance to monitor the status of the subterranean biodiversity, standardised methodologies to record biotic and abiotic data in these environments are still not fully adopted, impeding therefore the creation of comparable datasets useful for monitoring the ecological condition in the subterranean environments and for conservation assessment of related species.
In this work we describe a methodology allowing the collection of standardised abiotic and biotic data in subterranean environments. To show this, we created a large dataset including information on environmental features (morphology and microclimate) and abundance of five predators (one salamander, three spiders and one snail) occurring in seven caves of the Monte Albo (Sardinia, Italy), an important biodiversity hotspot. We performed 77 surveys on 5,748 m2 of subterranean environments througout a year, recording 1,695 observations of the five cave predators. The fine-scale data collection adopted in our methodology allowed us to record detailed information related to both morphology and microclimate of the cave inner environment. Furthermore, this method allows us to account for species-imperfect detection when recording presence/abundance data.
Dataset, standardised data collection, cave biology, troglophiles, salamander, spider, snail, monitoring, endangered species
Subterranean environments represent peculiar habitats with an extraordinary biodiversity, including species with unique adaptive traits (
Subterranean environments are inhabited by peculiar animal communities (
Considering the complexity of exploring subterranean habitats (
The aim of this paper is to describe a standardised method to record fine-scale ecological and biological data in subterranean environments. To prove this, we here provide a large dataset recorded using the proposed approach (Suppl. material
The five monitored predator species: a) the salamander Hydromantes flavus; b) the spider Metellina merianae; c) the spider Tegenaria sp.; d) the snail Oxychilus oppressus; e) the spider Meta bourneti.
Recommendations to adopt this survey method:
We monitored 7 caves located in different areas of the Monte Albo massif (Fig.
Abiotic data collection
Morphology
Caves were explored entirely or up to the point reachable without speleological equipment. Using a laser meter (Anself RZE-70, accuracy 2 mm), we recorded the maximum height and width of the cave entrance (i.e. the main connection with the external environment). Using a tape meter, the cave environment was divided into 3-metre cave sectors. At the end of each cave sector, we recorded the maximum height and width using a laser meter. At the same point, we estimated the average maximum wall irregularity (i.e. presence of wall protuberances). To estimate wall irregularity, we used a string of one metre length, flattened vertically against the most irregular part of each cave wall (left and right), at a height ranging from 0.5 to 2 m; a tape meter was then used to measure the linear distance between the two extremities of the string (
Microclimate
During each season, air temperature and humidity were recorded in the external surroundings of each cave, in a shaded area 5-10 m from the entrance, using a Lafayette TDP92 thermo-hygrometer (accuracy: 0.1°C and 0.1%). At the end of each cave sector, the average air temperature and humidity were estimated by averaging data recorded at ground level and at 2.5 m height (or at the ceiling if sector height was lower). Microclimatic data were recorded paying attention to limit researcher influence (
Species data collection
Data on species occurrence and on the number of detected individuals were obtained using the Visual Encounter Survey (i.e. the surveyor visually inspected the whole cave sector without disturbing species) (
A dataset is provided to be readily used with R statistical software.
Several scientific studies support the reliability of the monitoring methodology proposed here (
The standardised methodology adpoted here and its overall repeatability, allowed the collection of comparable data from different environments during multiple time series (e.g. seasons or years). This makes it possible to identify potential changes of the local environmental conditions, giving the chance to promptly plan habitat conservation actions (
Species can be overlooked, especially the small-sized ones: a lack of observation does not mean a true absence (
Sites were surveyed twice per season with a maximum gap ≤ 7 days, allowing us to meet prerequisites for population closure and to limit variation of climate conditions, which can, in turn, affect individuals’ activity (
Abundance data collected in a relatively short time allows us to estimate population size, thus providing the fundamental information to perform species conservation assessments (
In order to consider possible differences in the activity of the studied species, surveys were performed during the four seasons. The studied species are usually more active at the end of the cold season (
The target species are not obligate cave species and they likely show day/night changes in their activity pattern (
The fine-scale standardised methodology described here allows us to characterise the multiple subterranean microhabitats (
This methodology, based on just observations, is appropriate for monitoring protected species (
The Monte Albo is listed as a Site of Community Importance (SCI) by European law (European Commission Habitats Directive 92/43/EEC), as it represents an important biodiversity hotspot including several endangered species (
40.4379 and 40.5701 Latitude; 9.5110 and 9.6815 Longitude.
The presence and abundance of the following five cave predators were recorded: The Monte Albo cave salamander Hydromantes flavus, the spiders Meta bourneti, Metellina merianae and Tegenaria sp., the land snail Oxychilus oppressus (Fig.
Detailed information on cave features and abundance of five predator species (Suppl. material
Column label | Column description |
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country | The name of the country in which the sampling was performed |
region | The name of the region in which the sampling was performed |
county | The name of the county in which the sampling was performed |
locationID | The unique name of the surveyed location |
eventDate | The date in which the survey was performed |
eventSeason | The season in which the survey was performed |
decimalLatitude | Coordinates of the latitute in WGS84 decimal degrees (N) |
decimalLongitude | Coordinates of the longitude in WGS84 decimal degrees (E) |
ElevationInMetres | Elevation (m a.s.l.) of the surveyed site |
entrance_heightValue | The maximum height of the cave entrance (m) |
entrance_widthValue | The maximum width of the cave entrance (m) |
external_temperatureValue | The outdoor air temperature (°C) measured at 5-10 m from the cave entrance |
external_humidityValue | The outdoor air humidity (%) measured at 5-10 m from the cave entrance |
branchID | The number of the cave branch |
sector_depthValue | The linear distance (m) of the sector from the cave entrance |
sector_heightValue | The maximum height (m) of the cave sector |
sector_widthValue | The maximum width (m) of the cave sector |
sector_wall_irregularityValue | The average wall irregularity (m) of the cave sector. This value tends to 1 when cave walls show low irregularity, while it gets smaller when the wall irregularity increases |
sector_temperatureValue | The seasonal average air temperature (°C) of the cave sector |
sector_humidityValue | The seasonal average air humidity (%) of the cave sector |
sector_max_illuminanceValue | The seasonal average maximum illuminance (lx) of the cave sector |
sector_min_illuminanceValue | The seasonal average minimum illuminance (lx) of the cave sector |
Hydromantes_flavusQuantityType | The typology of data recorded for Hydromantes flavus Stefani, 1969 (Urodela: Plethodontidae): individual |
Hydromantes_flavusQuantity | Number of observed Hydromantes flavus |
Meta_bournetiQuantityType | The typology of data recorded for Meta bourneti (Roberts 1995) (Araneae: Tetragnathidae): individual |
Meta_bournetiQuantity | Number of observed Meta bourneti |
Meta_bourneti_eggQuantityType | The typology of data recorded for Meta bourneti egg sacks: cocoons |
Meta_bourneti_eggQuantity | Number of observed Meta bourneti egg sacks |
TegenariaQuantityType | The typology of data recorded for Tegenaria Latreille, 1804 (Araneae: Agelenidae): individual |
TegenariaQuantity | Number of observed Tegenaria |
Tegenaria_eggQuantityType | The typology of data recorded for Tegenaria egg sacks: cocoons |
Tegenaria_eggQuantity | Number of observed Tegenaria egg sacks |
Metellina_merianaeQuantityType | The typology of data recorded for Metellina merianae (Scopoli, 1763) (Araneae: Tetragnathidae): individual |
Metellina_merianaeQuantity | Number of observed Metellina merianae |
Metellina_merianae_eggQuantityType | The typology of data recorded for Metellina merianae egg sacks: cocoons |
Metellina_merianae_eggQuantity | Number of observed Metellina merianae egg sacks |
Oxychilus_oppressusQuantityType | The typology of data recorded for Oxychilus oppressus (Shuttleworth, 1877) (Gastropoda: Oxychilidae): individual |
Oxychilus_oppressusQuantity | Number of observed Oxychilus oppressus |
recordedBy | The Name and Surname of person recording the data |
Enrico Lunghi is supported by the Chinese Academy of Sciences President's International Fellowship Initiative for postdoctoral researchers, National Speleological Society and Instrumentl.
We thank P. Cardoso and S. Mammola for useful comments. E.L., M.M. R.M. and G.F.F. participated in data collection; E.L. prepared tables, figures and first draft of the manuscript; M.V., R.M., G.F.F., Y.Z. and C.C contributed in reviewing the manuscript.
Detailed information on morphology and microclimate of the surveyed caves in the Monte Albo massif and number of observed individuals belonging to five predator species exploiting these caves. For spiders, the number of the observed cocoons is also reported. NA means that the data is not available.