DOI: 10.5061/dryad.3tx95x6qx
title: Urban environments promote adaptation to multiple stressors

description: Anthropogenic activities have drastically changed environmental conditions
 worldwide, negatively impacting biodiversity and ecosystem services. At
 the same time, the majority of the human population lives in urban areas
 that are greatly altered from natural habitats. Nevertheless, many species
 thrive in urban environments. To improve our knowledge of evolution and
 adaptation in these anthropogenically impacted habitats, we conducted the
 widest series of stress experiments to date with three marine taxa: one
 mussel and two gammarid species. We compared intraspecific populations
 from protected and human-altered habitats to determine their tolerance to
 salinity, temperature and partial pressure of CO2 in water (pCO2) regimes.
 Populations from impacted habitats typically outperformed protected
 habitat populations, with individuals from the most impacted habitat being
 the most robust. We propose that urban populations are adapting to life in
 disturbed environments — this adaptation concurrently promotes more
 resilient rescue populations but potentially confers increased invasion
 risk from non-native species.
description: Populations of one mussel (i.e., <em>Mytilus</em>
 sp.) and two gammarid species (i.e., <em>Gammarus locusta</em>
 and <em>G. salinus</em>) were collected in protected and
 human-altered habitats (i.e., impacted) in the Baltic Sea in Germany. The
 protected habitat was Schleimünde (Maasholm), while the human-altered
 habitat was the Kiel fjord, with three locations: i) downtown Kiel; ii)
 Kiel canal; and iii) Falckenstein beach. Species were collected from May
 2016 until January 2021, depending on when a particular species/population
 experiment was conducted as well as sampling logistics. Two different
 types of experiments were conducted for each population of each species,
 with two crossed stressors: i) temperature – pCO2 experiments; and ii)
 temperature – salinity experiments. In both types of these
 multiple-stressor experiments with factorial stressor arrangements,
 following the acclimatization period to laboratory environment, the stress
 tests were conducted using ten mean-size adult individuals per replicate;
 except in two experiments when eight and nine individuals were used due to
 a lack of individuals (i.e., in a temperature – pCO2 experiment with
 <em>Mytilus</em> sp. from Schleimünde and a temperature –
 salinity experiment with <em>G. locusta</em> from
 Schleimünde). The experimental individuals were transferred from the
 acclimation conditions to the experimental conditions without gradual
 adjustments. Three replicates were conducted for each treatment. Mussel
 experiments were performed in 5 L aquaria, whereas those for gammarids
 were in 2 L aquaria containing artificial habitat structures to provide
 complexity of habitat. The experiments lasted for 30 days, with mortality
 checked daily. Light and feeding regimes were kept the same as during the
 acclimation period. Every ten days, 50% of the water was exchanged with
 previously prepared water to ensure the desired temperature, salinity and
 pCO<sub>2</sub> conditions were kept.
description: # Urban environments promote adaptation to multiple stressors
 [https://doi.org/10.5061/dryad.3tx95x6qx](https://doi.org/10.5061/dryad.3tx95x6qx) ## Description of the data and file structure There are two files: the first one containing data of the temperature – pCO2 experiments, and the second one containing data of the temperature – salinity experiments. The files contain information for the ambient and treatment experiments by providing data on survival of tested individuals in manipulated temperature, pCO2 and/or salinity conditions. Records of temperature, pCO2 and/or salinity are included as well. ### Files and variables #### File: Temperature\_-\_pCO2.xlsx **Description:** Each excel sheet (i.e., Mytilus sp. Schleimünde, Mytilus Kiel Fjord, G. locusta Schleimünde, G. locusta Falckenstein, G. salinus Schleimünde, G. salinus Kiel Kanal, and G. salinus Kiel Fjord) represents one experiment for one population of Mytilus sp., Gammarus locusta and Gammarus salinus, respectively. Schleimünde, Kiel Fjord, Falckenstein, and Kiel Kanal are sampling locations of experimental populations. ##### Variables *  *Date*: Dates of the experiment *  *Day*: Day of the experiment *  *Number of individuals*: Number of alive individuals for a particular day of the experiment *  *Average survival*: Average survival of alive individuals for a particular day of the experiment out of the three replicates *  *pH*: averaged pH measured for a particular day of the experiment out of the three replicates *  *temperature*: averaged temperature measured for a particular day of the experiment out of the three replicates *  *n/a*: not applicable - due to 100% mortality of experimental individuals temperature and pH parameters were not measured any more #### File: Salinity\_-\_temperature.xlsx **Description:** Each excel sheet (i.e., Mytilus sp. Schleimünde, Mytilus Kiel Fjord, G. locusta Schleimünde, G. locusta Falckenstein, G. salinus Schleimünde, G. salinus Falckenstein, G. salinus Kiel Kanal, and G. salinus Kiel Fjord) represents one experiment for one population of Mytilus sp., Gammarus locusta and Gammarus salinus, respectively. Schleimünde, Kiel Fjord, Falckenstein, and Kiel Kanal are sampling locations of experimental populations. ##### Variables *  *Date*: Dates of the experiment *  *Day*: Day of the experiment *  *Number of individuals*: Number of alive individuals for a particular day of the experiment *  *Average survival*: Average survival of alive individuals for a particular day of the experiment out of the three replicates *  *temperature*: averaged temperature measured for a particular day of the experiment out of the three replicates \*  *salinity*: averaged salinity measured for a particular day of the experiment out of the three replicates *  *n/a*: not applicable - due to 100% mortality of experimental individuals temperature and salinity parameters were not measured any more ## Code/software The R code used for all of the GLMs has been provided at Zenedo at: [https://doi.org/10.5281/zenodo.14616924](https://doi.org/10.5281/zenodo.14616924).