DOI: 10.5061/dryad.jh9w0vt8s
title: Raw microclimate data from caves and mines in New Brunswick, Canada

description: We document white-nose syndrome (WNS), a lethal disease of bats caused by
 the fungus Pseudogymnoascus destructans (Pd), and hibernacula microclimate
 in New Brunswick, Canada. Our study area represents a more northern region
 than is common for hibernacula microclimate investigations, providing
 insight as to how WNS may impact bats at higher latitudes. Hibernacula
 microclimate is important in hibernaculum selection by bats and may also
 be an important factor influencing WNS-associated bat mortality rates. To
 determine the impact of the March 2011 arrival of Pd in New Brunswick and
 the role of hibernacula microclimate on hibernating bat mortality, we
 surveyed bat numbers at hibernacula twice a year from 2009 – 2015. We also
 collected data from iButton temperature loggers deployed at all sites and
 gathered temperature and humidity data from HOBO loggers at three sites.
 Bat species found in New Brunswick hibernacula include Myotis lucifugus
 (Little Brown Bat) and M. septentrionalis (Northern Long-eared Bat), with
 small numbers of Perimyotis subflavus (Tricolored Bat). All known
 hibernacula in the province were Pd-positive with WNS-positive bats by
 winter 2013. A 99% decrease in the over-wintering bat population in New
 Brunswick was observed between 2011 and 2015. We did not observe P.
 subflavus during surveys 2013 – 2015 and the species appears to be
 extirpated from these sites. Bats did not appear to choose hibernacula
 based on winter temperatures, but dark zone (zone where no light
 penetrates) winter temperatures did not differ among our study sites,
 likely due to the geographically small sampling area. Dark zone
 temperatures did not vary among years, unlike hibernacula entrance
 temperatures, but both locations were affected by the presence of flowing
 water. Winter dark zone temperatures were warmer and less variable than
 entrance or above ground temperatures. We observed visible Pd growth on
 hibernating bats in New Brunswick during early winter surveys (November),
 even though hibernacula temperatures were colder (~ 4 – 5°C) than optimum
 for in vitro Pd growth (12.5 – 15.8°C). This suggests that cold
 hibernacula temperatures encountered near the apparent northern range
 limit for Pd do not sufficiently slow fungal growth to prevent the onset
 of WNS and associated bat mortality over the winter. As WNS continues to
 spread west across continental North America, the severity of WNS-related
 mortality may therefore be greater at northern latitudes where bat
 hibernation periods are longer, despite apparent suboptimal temperatures
 for Pd growth.
description: We monitored six limestone
 caves, two gypsum caves, and three abandoned manganese mines in southern
 New Brunswick, Canada, 2009 ‒ 2015 (site map in Vanderwolf et al. 2012).
 We placed air temperature logger iButtons (model DS1921G, ±
 1˚C, Maxim Integrated Products, Inc., Sunnyvale, California) in caves and
 mines in December 2011 and retrieved them August 2017. We set iButtons to record air
 temperature twice daily (0230 and 1430 hrs.) to capture daily temperature
 extremes and increase longevity of the devices. We deployed three iButtons
 at each site: we placed one 1 – 2 m from the ground on a wall ledge near
 the ceiling in the twilight zone (i.e. the entrance area where some light
 penetrates 7 ± 5 m into the cave), a second under similar circumstances in
 the dark zone (zone where no light penetrates), and attached a third to a
 tree at chest height 50 – 200 m from each hibernaculum entrance. We placed
 iButtons in the dark zone in passage or chamber areas where bats roosted
 (if bats were present) 45 ± 26 m SD (range 16 – 200 m) from the entrance,
 with placement depending on hibernaculum length and roosting location of
 hibernating bats. Dark zone iButtons were placed in areas with the largest
 concentration of bats, which was generally not the deepest part of each
 hibernaculum (total lengths ranged from 74 – 515 m). To avoid loss inside
 caves, we placed iButtons in perforated (to facilitate airflow)
 translucent plastic boxes. iButtons outside caves were placed in plastic
 camouflaged boxes (painted brown to deter theft) with a hole drilled in
 the bottom to allow water drainage. Due to iButton failures, we placed two
 iButtons in each box starting in 2013 (paired iButtons). When available we
 used the mean value of paired iButtons for analysis.
 We
 deployed temperature/relative humidity loggers (HOBO model U23-001; ±
 0.45˚C, ± 2.5% from 10% to 90% RH and ± 5% at &gt;90% RH, Onset
 Computer Corporation, Bourne, MA) at three sites in conjunction with
 iButtons: White Cave, Markhamville Mine, and Berryton Cave. We deployed
 HOBOs April 2014 and retrieved them August 2017. We placed three HOBOs at
 each site near existing iButtons (twilight zone/entrance, dark zone, and
 outside the hibernaculum) and programmed them to record air temperature
 and relative humidity twice daily (0230 and 1430 hrs.). HOBOs outside
 hibernacula were tied at chest height to the same tree as camouflaged
 iButton boxes, with the HOBO placed just above the iButtons and the sensor
 pointing towards the ground. We wrapped HOBOs in a tube of black foam pipe
 insulation for protection and camouflage, while ensuring that the sensor
 was open to the air at the bottom of the tube. Loggers tied to trees were
 below the forest canopy, which probably modulated local extremes in
 temperature and humidity. We downloaded data from iButtons and HOBOs twice
 a year during bat counts and replaced malfunctioning iButtons. The
 relative humidity sensor of the HOBO logger deployed in the dark zone of
 White Cave failed September 2016, so no data were available after that
 date. During visits
 March 2012 ‒ May 2015 we also measured air temperature and relative
 humidity with a Kestrel 3000 Handheld weather meter (MPN# 0830, ± 0.04˚C,
 ± 1% RH, Boothwyn, Pennsylvania, USA). Kestrel measurements took some time
 to stabilize, particularly for relative humidity, so the device was
 temporarily attached to a tree adjacent to the hibernaculum entrance for
 measurements above ground, and positioned on the hibernacula floor for
 measurements inside passages while we performed bat counts.
 We converted relative
 humidity to water vapor pressure because relative humidity is less
 informative and potentially misleading (Kurta, 2014). We calculated
 equilibrium vapor pressure using temperature data and the quadratic
 formula of Tabata (1973), and then determined actual vapor pressure (hPa)
 by multiplying the saturation vapor pressure by the relative humidity as
 recorded by HOBOs. We incorporated previous iButton temperature data
 collected from the same sites October 2009 to October 2010 (Vanderwolf
 <i>et al.</i>, 2012) in the analysis.
 Kurta, A. (2014) ‘The misuse of relative humidity in
 ecological studies of hibernating bats’, <i>Acta
 Chiropterologica</i>, 16(1), pp. 249–254. doi:
 10.3161/150811014x683444.
 Tabata, S. (1973) ‘A simple but accurate formula for
 the saturation vapor pressure over liquid water’, <i>Journal of
 Applied Meterorology</i>, 12, pp. 1410–1411.
 Vanderwolf, K. J. <i>et al.</i> (2012)
 ‘Bat populations and cave microclimate prior to and at the outbreak of
 white-nose syndrome in New Brunswick’, <i>Canadian
 Field-Naturalist</i>, 126(2), pp. 125–134.
description: There are temporal gaps in the data due to logger failure but
 these do not show up as missing values. The 'iButton data' tab
 also include temperature data from HOBO loggers at the bottom. The
 'Kestral data' tab has multiple missing values indicated as a
 blank cell. Any reference to 'Mark small' refers to Markhamville
 Mine 2. Water temperature data was collected during a previous study and
 collection methods are described there (Vanderwolf et al. 2017).
 Vanderwolf, K. J., McAlpine, D. F. and McGuire, L. P.
 (2017) ‘Hibernacula water chemistry and implications for hibernating
 bats’, <i>Journal of Mammalogy</i>, 98(6). doi:
 10.1093/jmammal/gyx111.