DOI: 10.5061/dryad.573n5tb79
title: Data from: Global change impacts on arid zone ecosystems: Seedling establishment processes are threatened by temperature and water stress

description: Recruitment for many arid-zone plant species is expected to be impacted by
 the projected increase in soil temperature and prolonged droughts
 associated with global climate change. As seed dormancy is considered a
 strategy to avoid unfavourable conditions, understanding the mechanisms
 underpinning vulnerability to these factors is critical for plant
 recruitment in intact communities, as well as for restoration efforts in
 arid ecosystems. This study determined the effects of temperature and
 water stress on recruitment processes in six grass species in the
 genus Triodia R.Br. from the Australian arid zone.
 Experiments in controlled environments were conducted on dormant and
 less-dormant seeds at constant temperatures of 25, 30, 35 and 40°C, under
 well-watered (Psisoil = -0.15 MPa) and water-limited
 (Psisoil = -0.35 MPa) conditions. Success at three key
 recruitment stages – seed germination, emergence and survival– and final
 seed viability of un-germinated seeds was assessed. For all
 species, less dormant seeds germinated to higher proportions under all
 conditions, however, subsequent seedling emergence and survival was higher
 in the more dormant seed treatment. An increase in temperature (35–40°C)
 under water-limited conditions caused 95–100% recruitment failure,
 regardless of the dormancy state. Ungerminated seeds maintained viability
 in dry soil, however, when exposed to warm (30-40°C) and well-watered
 conditions, loss of viability was greater from the less dormant seeds
 across all species. This work demonstrates that the transition from seed
 to established seedling is highly vulnerable to microclimatic constraints,
 and represents a critical filter for plant recruitment in the arid-zone.
 As we demonstrated temperature and water stress-driven mortality between
 seeds and established seedlings, understanding how these factors influence
 recruitment in other arid-zone species should be a high priority
 consideration for management actions to mitigate the impacts of global
 change on ecosystem resilience. The knowledge gained from these outcomes
 must be actively incorporated into restoration initiatives.
description: This data file contains the data described in Lewandrowski et al.
 ECE-2020-07-01165. The first worksheet containts the data from
 the petri-dish experiment that determined germination and the subsequent
 condition of seeds when they did not germinate (either being dead or
 alive) - the viable proportion is the sum of the germinated and
 ungermianted alive seeds. The data are stacked, and would need to be
 subsetted by the condition. The second worksheet contains the data from
 the climate chamber experiment that assessed seedling emergence and
 surival, and germination at the completion of the experiment. The data are
 also currently stacked and would need to be subsetted by process. The
 third worksheet contains data of the remaining ungerminated seeds after
 they were exposed to the different temperature and water stress
 combinations. The ungerminated seeds were tested for their viability in a
 petri dish experiment whereby dead and alive proportions were determined -
 the viable proportion is the sum of the germinated and alive seeds. The
 data are stacked, and would need to be subsetted by the condition. We also
 provide a detailed README file that contains definitions for the different
 columns. For detailed methodology please refer to our manuscript or
 contact wolfgang.lewandrowski@dbca.wa.gov.au for assistance.