DOI: 10.5061/dryad.j0zpc86bb
title: Ant community dynamics in the Big Thicket National Preserve of east Texas

description: Rare and extreme climatic events can leave important but
 difficult-to-study legacies for ecological communities. Theory suggests
 that the relative abundance and even presence of species in communities
 may be driven as much by historical contingencies associated with rare
 events as by filtering from average environmental conditions. Much of what
 we know about the consequences of extreme events comes from opportunistic
 studies, where ecologists were in the right place at the right time.
 Climate change forecasts for the 21st century include an increase in
 frequency of extreme events, and ecologists are increasingly called upon
 to predict their consequences. We must therefore exploit opportunities to
 quantify the ecological effects of climatic extremes when and where we
 can. This study examined how a rare and extreme forcing event – the
 unprecedented flooding associated with Hurricane Harvey – modified the
 composition of ant communities in east Texas. We surveyed ant communities
 of the Big Thicket National Preserve (BTNP) through pitfall trapping at 18
 sites throughout BTNP. We conducted twice-annual sampling in 2014 and
 2015, before the hurricane, and monthly sampling for one year in the
 aftermath of Hurricane Harvey (August 2017), beginning in November 2017.
 BTNP ant communities include many native species as well as two
 conspicuous invaders: the fire and Solenopsis invicta and the tawny crazy
 ant Nylanderia fulva. Thus, beyond characterizing overall trends in ant
 community composition, we were particularly interested in the temporal
 dynamics of these species' distribution and abundance throughout the
 Big Thicket preserve, and their responses to Hurricane Harvey. 
description: Sampling took place at 18 sites spanning 11 administrative units
 of the Big Thicket National preserve. Sampling was conducted twice per
 year (in May and September) for two years (2014 and 2015), and then
 monthly from November 2017 through November 2018 (with the exception of no
 sampling in December 2018). Locations for sample sites were constant
 across sampling events with the exception of one site that was relocated
 nearby (within 1 km) after it became inaccessible in Fall 2015 due to
 localized flooding. At each sampling site, five pitfall traps were placed
 at each corner of a 10 m by 10 m square with one pitfall in the center of
 the square (these are called "stations" and labeled A-E). Each
 pitfall consisted of a 50 mL centrifuge tube filled with 25 mL of
 reverse-osmosis water and a few drops of unscented dish soap to break the
 surface tension. The pitfalls were positioned such that the open lid of
 the tube was flush with the surface of the ground and were recovered after
 seven days. After each sampling period, we transferred ants into vials
 containing 70% ethanol and stored the vials at -20 degrees C. Workers were
 keyed to genus and species. 
description: The main data file is Pitfall_Data.csv. Each row of this data
 frame gives the abundance of one species at a given sampling date - site -
 station. If there were no ants captured for a given date - site - station
 then the "Ants?" field is given a zero. When multiple species
 were captured for a given date - site - station these are reported in
 separate rows. Site numbers correspond to those in the
 Site_Characteristics.csv data file.  The Site_Data.csv
 file gives additional information about cases of missing observations in
 the pitfall data. This data frame indicates, for each date - site -
 station, whether the site was accessible for set-up, whether it was
 accessible to re-visit, and whether pitfalls were retrieved. This data
 frame also provides measurements of volumetric water content (VWC), which
 were collected in 2018 but not previous years.  All
 metadata are described in the ReadMe file.