Global maps of soil temperature.

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km <sup>2</sup> resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km <sup>2</sup> pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Intensive grazing by Barnacle geese depletes High Arctic seed bank

Studies in the Canadian Arctic show dramatic effects of increased goose grazing on vegetation structure and soil conditions, but little is known of the role of goose grazing in the European Arctic. We focused on how geese might affect plant recruitment via effects on seed production and soil seed bank in High Arctic Svalbard. Experimental grazing by captive Barnacle geese (Branta leucopsis (Bechstein, 1803)) decreased flower densities both at normal and at high grazing pressure. Geese showed a clear preference for reproductive rather than vegetative shoots. Soil samples collected inside and outside 7-year-old exclosures in an intensively goose-grazed area revealed significant effects on the germinable soil seed bank. The density of viable seeds in the top soil layer inside exclosures was six times higher than in grazed plots. Lower densities of viable seeds occurred in the basal than in the top layer but there was no difference in basal layer seed density between exclosed and grazed plots. This study shows that geese have strong effects on floral abundance and consequently on the seed bank. We argue that goose grazing in these systems influences the potential for recovery after a disturbance event and thus the long-term plant species diversity and dynamics.