DOI: 10.5061/dryad.2b906
title: Data from: The evolution of environmental tolerance and range size: A comparison of geographically restricted and widespread Mimulus

description: The geographic ranges of closely related species can vary dramatically,
 yet we do not fully grasp the mechanisms underlying such variation. The
 niche breadth hypothesis posits that species that have evolved broad
 environmental tolerances can achieve larger geographic ranges than species
 with narrow environmental tolerances. In turn, plasticity and genetic
 variation in ecologically important traits and adaptation to
 environmentally variable areas can facilitate the evolution of broad
 environmental tolerance. We used five pairs of western North American
 monkeyflowers to experimentally test these ideas by quantifying
 performance across eight temperature regimes. In four species pairs,
 species with broader thermal tolerances had larger geographic ranges,
 supporting the niche breadth hypothesis. As predicted, species with
 broader thermal tolerances also had more within-population genetic
 variation in thermal reaction norms and experienced greater thermal
 variation across their geographic ranges than species with narrow thermal
 tolerances. Species with narrow thermal tolerance may be particularly
 vulnerable to changing climatic conditions due to a lack of plasticity and
 insufficient genetic variation to respond to novel selection pressures.
 Conversely, species experiencing high variation in temperature across
 their ranges may be buffered against extinction due to climatic changes
 because they have evolved tolerance to a broad range of temperatures.
description: Mean thermal performance
 data for 10 Mimulus species File
 name: <strong>Mimulus_thermal_performance_data.csv</strong>
   This data file includes
 mean performance, measured as relative growth rate in stem length or leaf
 number, for each family of each Mimulus species at 15, 20, 25, 30, 35, 40,
 45, and 50 degrees Celsius (see publication for further details). Column
 names are as follows: <strong>species</strong>: species of
 Mimulus. <strong>family</strong>: unique ID corresponding to
 full-sibling seed family. <strong>temperature</strong>:
 daytime temperature of growth chamber.
 <strong>RGR_stem</strong>: mean relative growth rate in stem
 length (in units of cm/cm/day) across individuals of each family.
 <strong>RGR_leaf</strong>: mean relative growth rate in leaf
 number (in units of leaf #/leaf #/day) across individuals of each
 family. 
  
 Raw thermal
 performance data for 10 Mimulus species File
 name: <strong>Mimulus_thermal_performance_data_raw.csv</strong>   This data file includes raw thermal performance, measured as relative growth rate in stem length or leaf number, for each individual of each Mimulus species at 15, 20, 25, 30, 35, 40, 45, and 50 degrees Celsius (see publication for further details). Column names are as follows: <strong>species</strong>: species of Mimulus. <strong>family</strong>: unique ID corresponding to full-sibling seed family. <strong>temperature</strong>: daytime temperature of growth chamber. <strong>stemLen1</strong>: length of primary stem in centimeters prior to imposing temperature treatment. <strong>leafNum1</strong>: number of true leaves &gt; 1mm in length prior to imposing temperature treatment. s<strong>temLen2</strong>: length of primary stem in centimeters after 7 days of exposure to temperature treatment. <strong>leafNum2</strong>: number of true leaves &gt; 1mm in length after 7 days of exposure to temperature treatment. <strong>RGR_stem</strong>: relative growth rate in stem length (in units of cm/cm/day). <strong>RGR_leaf</strong>: relative growth rate in leaf number (in units of leaf #/leaf #/day). Note that we originally only provided mean thermal performance data for each family in the data file above. We have now uploaded a new file of raw data from which these means were calculated.