DOI: 10.5061/dryad.pzgmsbctw
title: Regional and fine-scale local adaptation in salinity tolerance in Daphnia inhabiting contrasting clusters of inland saline waters

description: Freshwater salinisation is an important threat to biodiversity, ecosystem
 functioning, and the provision of ecosystem services. Therefore,
 understanding the capacity of species to adapt to salinity gradients is
 crucial. Clusters of naturally saline habitats represent ideal test cases
 to study the extent and scale of local adaptation to salinisation. We
 studied local genetic adaptation of the water flea Daphnia magna, a key
 component of pond food webs, to salinity in two contrasting landscapes - a
 dense cluster of sodic bomb crater ponds and a larger-scale cluster of
 soda pans. We show regional differentiation in salinity tolerance
 reflecting the higher salinity levels of soda pans versus bomb crater
 ponds. We found local adaptation to differences in salinity levels at the
 scale of tens of metres among bomb crater pond populations but not among
 geographically more distant soda pan populations. The population-level
 salinity tolerance range was reduced in more saline bomb crater ponds
 through an upward shift of the minimum salt tolerance observed across
 clones and a consequent gradual loss of less tolerant clones in a nested
 pattern. Our results show genetic adaptation to salinity gradients at
 different spatial scales and fine-tuned local adaptation in neighbouring
 habitat patches in a natural landscape.
description: # Data from: Regional and fine-scale local adaptation in salinity
 tolerance in Daphnia inhabiting contrasting clusters of inland saline
 waters Brief summary The
 data package contains two datasets: * Brans_et_al_data_2024_raw.csv *
 Brans_et_al_data_2024_EC50 and environmental variables.csv Datasets of the
 recorded variables (1) Brans_et_al_data_2024_raw.csv This dataset contains
 information on the survival of Daphnia magna after 24 and 48 hours of
 exposure to the experimental salinity levels. For details on the
 experiment, sampling, and sample processing, see Brans et al. (2024).
 Variable names with descriptions: *pond type: type of original habitat of
 the Daphnia populations, i.e. soda pan (SP) or bomb crater pond (BC).
 *pop: The ID of the pond of origin of each Daphnia population. IDs of bomb
 crater ponds are numbers given by the authors at the first mapping of all
 ponds in 2014. Abbreviations for soda pans: APME - Apetloner
 Meierhoflacke, HERR - Herrnsee, MSTI - Mittlerer Stinkersee, OWOR -
 Östliche Wörthenlacke, RUND - Runde Lacke, SECH - Sechsmadlacke, ZICK -
 Zicklacke. For the geographic coordinates of the habitats, see Brans et
 al. (2024). *clone: The ID of each clone within the populations.
 *clone_id: Unique ID of each clone. *conc: Experimental salt (NaHCO3)
 concentration (g/l). *replicate: Number of replicate on the clonal level
 out of 3 replicates. *mortality_24: Number of dead individuals after 24
 hours of exposure. *mortality_48: Number of dead individuals after 48
 hours of exposure. *total amount animals: Number of Daphnia individuals
 used per experimental replicate. (2) Brans_et_al_data_2024_EC50 and
 environmental variables.csv This dataset contains the calculated EC50
 values as well as the local environmental characteristics of the ponds.
 Variable names with descriptions: *clone_id: As in
 Brans_et_al_data_2024_raw.csv. *EC50_24h: EC50 values calculated from
 mortality after 24 hours based on 3 replicates at the clonal level as
 described in Brans et al. (2024). *EC50_48h: EC50 values calculated from
 mortality after 48 hours based on 3 replicates at the clonal level as
 described in Brans et al. (2024). *pond type: As in
 Brans_et_al_data_2024_raw.csv. *pop: As in Brans_et_al_data_2024_raw.csv.
 *cond: Conductivity (mS/cm) measured at the field as described in Brans et
 al. (2024). *sal: Pond salinity (g/L) calculated from conductivity as
 described in Brans et al. (2024). *TSS: Concentration of total suspended
 solids (g/L) measured at the field as described in Brans et al. (2024).
 *chla: Concentration of chlorophyll a (ug/L) measured at the field as
 described in Brans et al. (2024). *pH: pH measured at the field as
 described in Brans et al. (2024). *water.depth: Water depth (cm) of the
 ponds measured at the field as described in Brans et al. (2024).
 *mean_spring: Mean spring salinity (g/L) calculated as described in Brans
 et al. (2024). *mean_summer: Mean summer salinity (g/L) calculated as
 described in Brans et al. (2024).