Macquarie Island microclimate data (iButton, island-wide 62 sites) Dec. 2016 – Dec.2017 - Azorella dieback

Brief description

This data set contains the raw temperature and humidity data recorded 4 hourly at 62 sites across the extent of Macquarie Island between 15/12/2016 and 03/01/2018. This dataset was created as part of AASP4312: Nowhere to hide? Conservation options for a sub-Antarctic keystone species.

The endemic, keystone species Azorella macquariensis (Macquarie cushion) has undergone rapid widespread decline in condition (dieback) across Macquarie Island in 2008/2009, resulting in its listing as critically endangered in 2010. Initial research suggests that Azorella dieback is likely driven by a decadal reduction in plant available water, as a result of a significantly changed regional climate, which may have facilitated a secondary putative pathogenic infection of weakened plants (Bergstrom et al. 2015, Whinam et al. 2014).

Sixty-two microclimate and Azorella condition sites were randomly stratified across Macquarie Island, using the terrain class model (AAS_4312_MI_Terrain_Class_Model) and spatial blocks to ensure the full breadth of microclimates were sampled on the plateau. The datalogger deployment elevation ranged from 125m above sea level (asl) to 373m asl. Methods are available in Dickson et al. in prep and Baker et al. in prep. To ensure a full set of microclimate data (temp and humidity) each site had a minimum of two DS1923 Hygrochon Temperature and Humidity iButtons (Maxim) and most had an additional DS1925 Thermochron iButton (Maxim) deployed (total 180). One Hygrochron was located at the central site point (A) and the second hygrochron 5-12 m away (B) collocated with a Thermochron on a separate patch of ground. iButtons were housed in light grey PVC containers in a free hanging fob. Three slits were cut in each side of the housing to increase airflow, while sheltering from direct solar radiation and precipitation. The housings were fixed to a wooden stake 4cm above the ground to assess the microclimate of the study’s focal species, Azorella macquariensis. Where possible iButtons were located away from vegetation. iButtons were set to record at high resolution, every 4 hours (starting at 03:00am), to get the most amount of data between seasons and to coincide with the 15:00 Bureau of Meteorology (BoM) readings. One Hygrochron was located at the BoM site, adjacent to the weather station and thermometers. iButtons were programed to start while on-site and had run out before retrieval, however occasionally dataloggers ran either side of deployment. The dates that the datalogger have been recorded within 4312_MI_temp_hum_62sites.xlxs for all iButtons and data trimmed to the dates of site deployment.

Basic iButtons site variables within a 1x1m quadrat (inc. slope, aspect, vegetation cover) were recorded and are available in 4312_MI_iButton_location_site_dets.xls. Related biotic and abiotic (inc, DEM derived topographic values) site variables for the associated biological monitoring site (706.86m^2 ) can be found in the data for AAS_4312_Azorella_condition_site_topo ( doi:10.26179/5bf382d899d95). A generalised site ‘map’ is included in 4312_MI_iButton_location_site_dets_interp_library.xlsx

Dataloggers were deployed on site between 15/12/2016 and 03/01/2018, where the median deployment was 338 days (min 293d and max 350d).

Data provided includes the following headings:
4312_MI_temp_hum_62sites.scv - SITE_CODE, DateTime (AEST; UTC+10:00), Temperature (deg), Humidity (%), Year, Month, Day, Hour, Site, iButton, type, deployment_start, deployment_end.

4312_MI_iButton_location_site_dets.xls: site name, location (UTM, GDA94), iButton number, date of establishment, distance and bearing to other iButtons on site, 1x1m quadrat data around iButtons (slope, aspect, vegetation cover, description), comments.

4312_MI_iButton_QA_notes.xlxs: site, ibutton, sitecode, deployment start and finish dates, serial numbers, type, data quality comments.

Interpretation libraries are provided for each file.

This dataset was created as part of Catherine Dickson's PhD thesis 'Impact of climate change on a sub-Antarctic keystone species Azorella macquariensis (Apiaceae)'.