DOI: 10.5061/dryad.4b8gththc
title: Data from: Climate refugia along Lake Superior’s shores: Disjunct arctic-alpine plants rely on cool shoreline temperatures but are unlikely to persist under climate warming

description: Climate refugia can serve as remnant habitat or stepping stones for
 species dispersal under climate warming. The largest freshwater lake by
 surface area, Lake Superior, USA and Canada, serves as a model system for
 understanding cooling-mediated local refugia, as its cool water
 temperatures and wave action have maintained shoreline habitats suitable
 for southern disjunct populations of arctic-alpine plants since
 deglaciation. Here we seek to explain spatial patterns and environmental
 drivers of arctic-alpine plant refugia along Lake Superior’s shores, and
 assess future risk to refugia under moderate (+3.5 °C) and warmest (+5.7
 °C) climate warming scenarios. First, we examined how the interactive
 effects of summer surface water temperatures and wind affected onshore
 temperatures, resulting in areas of cooler refugia. Second, we developed
 an ecological niche model for presence of disjunct arctic-alpine refugia
 (pooling 1253 occurrences from 58 species) along the lake’s shoreline.
 Third, we fit species distribution models for 20 of the most common
 arctic-alpine disjunct species and predicted presence to identify refugia
 hotspots. Finally, we used the two climate warming scenarios to predict
 changes in presence of refugia and disjunct hotspots. Bedrock type,
 elevation above water, inland distance, July land surface temperature from
 MODIS/Terra satellite, and near-shore depth of water were the best
 predictors of disjunct occurrences. Overall, we predicted 2,236 km of the
 shoreline (51%) as disjunct refugia habitat for at least one species under
 current conditions, but this was reduced to 20% and 7% with moderate (894
 km) and warmest (313 km) climate change projections.
description: # Title of Dataset: Climate refugia along Lake Superior’s shores: disjunct
 arctic-alpine plants rely on cool shoreline temperatures but are unlikely
 to persist under climate warming --- This dataset contains species
 occurrence records for 59 disjunct arctic-alpine species at Lake Superior.
 Hillman_species_occurrences_raw_data.csv contains location data for all
 occurrence records, as well as spatial data for elevation, bedrock type,
 depth of water within 10 km of shore, log of Euclidean distance from
 shore, and land surface temperature from MODIS/Terra satellite. Data were
 used to build species distribution models for all species considered
 disjunct and 21 most common disjunct species. Variable list: Point -
 Number of points assigned to either a species occurrence or a randomly
 generated pseudoabsence point pres_abs - Whether species is present or not
 (1 for present, 0 for absent) Species - Species that is present at that
 location Common name - Common name for species present at that location
 Source - Data source for species occurrence record (MNHHIS = Minnesota
 Department of Natural Resources, NHIC = Ontario's Natural Heritage
 Information Centre, GBIF = Global Biodiversity Information Facility)
 Location - Province or State where location occurs Easting - Geographic
 easting of point location, given in North American Lambert Conformal Conic
 Northing - Geographic northing of point location, given in North American
 Lambert Conformal Conic Elevation - Elevation (m) of each point above the
 surface of the water Bedrock - Code for bedrock type at point location
 (1=Sedimentary, 2=Metamorphic, 3=Igneous,4=Igneous volcanic Depth_10km -
 Average depth of water within 10 km of shore for each point Log_euc_dist -
 Log of Euclidean distance between each point and edge of the water LST -
 Average July Land Surface Temperature at each point
 Hillman_land_temperature_raw_data.csv contains MODIS land surface
 temperature data for 900 randomly generated points within the study area,
 as well as July water surface temperature and average windspeed values
 associated with each point. These data were used in a generalized linear
 model to examine the relationship between offshore drivers and cool
 shorelines. Variable list: Point - Number of random point assigned to each
 location Easting - Geographic easting of point location, given in North
 American Lambert Conformal Conic Northing - Geographic northing of point
 location, given in North American Lambert Conformal Conic LST - Average
 July Land Surface Temperature at the point location wst_j_25km - Average
 July water surface temperature within 25 km of shore for each point
 mean_wind - Average July windspeed for each point ## Sharing/Access
 information Species occurrence records from Minnesota Department of
 Natural Resources (MNHIS), and Ontario's Natural Heritage Information
 Centre (NHIC) are provided at a coarser resolution due to the sensitive
 nature of rare and tracked species. Additional species occurrence records
 publicly available at: Global Biodiversity Information Facility:
 [https://www.gbif.org/](https://www.gbif.org/)