Long-term salinity exposure reveals site-specific physiological and behavioral responses in coastal and inland toads
Data files
Jul 24, 2025 version files 32.11 KB
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Data.csv
16.03 KB
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MetaData.csv
4.36 KB
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README.md
11.72 KB
Abstract
This dataset is relative to a study investigating the long-term physiological and behavioral responses of adult Bufo spinosus (spined toads) to chronic environmental salinity: “Long-term salinity exposure reveals site-specific physiological and behavioral responses in coastal and inland toads”. The experiment aimed to evaluate the effects of 7-month exposure to freshwater (0 g.l-1), moderate (2 g.l-1) or high (4 g.l-1) salinity levels, simulating current and future scenarios of habitat salinization.
Toads were collected from two distinct populations: coastal (naturally salt-exposed) and inland (naïve to salinity), and acclimated in freshwater prior to treatment. A wide range of metrics was recorded before and after treatment, including size, plasma hormone levels (testosterone, triiodothyronine), plasma osmolality, relative telomere length, and other where measured only after treatment: metabolic rate, thermal preference, cutaneous evaporative water loss, immune parameters (NL ratio), and several behavioral traits such as defensiveness, activity, and prey capture efficiency.
The dataset allows for assessment of both population differences and salinity treatment effects on adult amphibians. These data contribute to understanding the physiological cost and potential adaptive mechanisms to chronic salinity stress.
Dataset DOI: 10.5061/dryad.w6m905r1s
Description of the data and file structure
Files:
- Data.csv: Main dataset containing individual-level observations across treatments.
- MetaData.csv: Variable definitions and explanations.
Variables
| Column | Explanation |
|---|---|
| ID | Unique identifiant of the individual |
| Site | Site of capture: either coastal or inland |
| Sex | Individual sex: male or female |
| SVL_at_capture | Size at capture (SVL= Snout Vent Length, mm) |
| AcclimationDuration | Duration of the acclimation period in freshwater before treatment (in days) |
| SVL_after_acclimation | Size after acclimation (SVL= Snout Vent Length, mm) |
| Osmolality_after_acclimation | Plasma osmolality measured after acclimation in freshwater (mOsm.kg^-1) |
| T3_after_acclimation | Triiodothyronine hormones, measured after acclimation in freshwater (ng.mL^-1) |
| Testo_after_acclimation | Testosterone levels, measured after acclimation in freshwater (ng.mL^-1) |
| TS_After_Acclimation | Telomeres' length, measured after acclimation in freshwater. The relative telomere length (expressed as T/S ratio) was calculated as the telomere copy number (T) relative to single-copy gene (S; RAG1). |
| Treatment | Salinity treatment appliedon 14/11/2022, for 7 months: 0,2 or 4 g.l-1 salinity |
| SVL_after_treatment | Size after after 7 month salinity treatment (SVL= Snout Vent Length, mm) |
| Osmolality_after_treatment | Plasma osmolality after 7 month salinity treatment (mOsm.kg^-1) |
| T3_after_treatment | Triiodothyronine hormones, measured after 7 month salinity treatment (ng.mL^-1) |
| Testo_after_treatment | Testosterone levels, measured after 7 month salinity treatment (ng.mL^-1) |
| TS_after_treatment | Telomeres' length, measured after 7 month salinity treatment. The relative telomere length (expressed as T/S ratio) was calculated as the telomere copy number (T) relative to single-copy gene (S; RAG1) |
| VO2M | O2 consumption of toads when placed in respirometrics chambers (corrected by individuals mass: ml.h.g^-1), measured after the 7 month exposure to salinity treatment |
| VCO2M | CO2 production of toads when placed in respirometrics chambers (corrected by individuals mass: ml.h.g^-1), measured after the 7 month exposure to salinity treatment |
| Preferred_Temperature | Individual preferred body temperature (°C), measured with an infrared thermometer in a thermal gradient, with one measure every 10 hours. This value is the mean of all 10 measures. Measured at the end of the 7 month exposure to salinity. |
| Dorsal_EWL | Dorsal cutaneous Evaporative Water Loss (CEWL, g.m^−2.h^−1) rates at 22°C, using an AquaFlux AF200 (Biox, London). Measured at the end of the 7 month exposure to salinity. |
| Ventral_EWL | Ventral cutaneous Evaporative Water Loss (CEWL, g.m^−2.h^−1) rates at 22°C, using an AquaFlux AF200 (Biox, London). Measured at the end of the 7 month exposure to salinity. |
| Patch_EWL | Patch cutaneous Evaporative Water Loss (CEWL, g.m^−2.h^−1) rates at 22°C, using an AquaFlux AF200 (Biox, London). Measured at the end of the 7 month exposure to salinity. |
| NL_ratio | Ratio of neutrophils to lymphocytes, measured on 100 leucocytes of the blood smears, after exposure to salinity treatments |
| Hiding_Frequency | When approaching the terraria, we recorded the fact that the toad was under its shelter or not (0: not under its shelter, 1: under its shelter) across 26 different occasions. This value is the mean of all hiding frequency recorded. Measured during exposure to salinity treatment |
| Defensiveness_Frequency | When approaching the terraria, we stimulated the toad and noted its reaction (0:neutral or 1:defensive) across 26 different occasions. This value is the mean of all defensiveness frequency recorded (measured during exposure to salinity treatment) |
| Mean_Activity | Activity was recorded on a scale of 1 to 5 (1 not being active, 5 being very active) across 26 different occasions. This value is the mean of all activities recorded (measured during exposure to salinity treatment) |
| Reaction_Time | During the behavioral test of prey capture (3 crickets), the behavior of toads was recorded for 2 minutes. During these 2 minutes, we extracted their reaction time (time before turning toward and staring at the prey, in seconds). This behaviour was measured during the 7 months exposure to salinity treatment |
| Efficiency | During the behavioral test of prey capture (3 crickets), the behavior of toads was recorded for 2 minutes. During these 2 minutes, we extracted the number of capture attempts and number of successful captures, allowing to compute a success rate. This behaviour was measured during the 7 months exposure to salinity treatment |
NA values represent missing data, either due to issues encountered during analyses (e.g., for the TS ratio) or because the variable could not be computed (e.g., efficiency could not be calculated if an individual did not attempt to catch a prey, and reaction time could not be determined if there was no reaction to the prey). For VO₂ and VCO₂ calculations, two individuals defecated during the measurements, and their data were therefore excluded from the analyses.