Ecological and societal disruptions by modern climate change are critically determined by the time frame over which climates shift beyond historical analogues. Here we present a new index of the year when the projected mean climate of a given location moves to a state continuously outside the bounds of historical variability under alternative greenhouse gas emissions scenarios. Using 1860 to 2005 as the historical period, this index has a global mean of 2069 (±18 years s.d.) for near-surface air temperature under an emissions stabilization scenario and 2047 (±14 years s.d.) under a ‘business-as-usual’ scenario. Unprecedented climates will occur earliest in the tropics and among low-income countries, highlighting the vulnerability of global biodiversity and the limited governmental capacity to respond to the impacts of climate change. Our findings shed light on the urgency of mitigating greenhouse gas emissions if climates potentially harmful to biodiversity and society are to be prevented.
1 March 2013 in Bulletin of the American Meteorological Society
Focal Taxa: Laupala, AMC Clade Drosophila, Tetragnatha, and Nesosydne. We assembled comprehensive occurrence datasets of all known records for each of the four lineages (included here), modeled their distributions using Maxent across the entire archipelago, and quantified niche overlap. Final base layers Mean Annual Air Temperature (°C), Mean Annual Rainfall (mm), Vegetation Height (m), and Normalized Difference Vegetation Index (NDVI) were selected based on optimum AUC values of trial models run. Rasters were obtained for the Rainfall Atlas of Hawaii, Climate of Hawaii, and USGS and resampled to a ~1km by ~1km resolution using smoothing for quantitative variables and nearest neighbor resampling for categorical variables (Giambelluca et al. 2013, Giambelluca et al. 2014, Hawaii Soil Survey 2000). Data presented here are the full set of georeferenced occurrence records, the filtered model inputs, and the final SDM models in ASCII format for each species. See the supplementary material in the corresponding publication (Hiller et al. 2017) for details on the georeferencing protocols used and a list of museum specimen numbers. Note that not all models were included in subsequent analyses due to poor quality (<3 records as model input or low AUC score)
Plant‐invasive success is one of the most important current global changes in the biosphere. To understand which factors explain such success, we compared the foliar traits of 41 native and 47 alien‐invasive plant species in Oahu Island (Hawaii), a location with a highly endemic flora that has evolved in isolation and is currently vulnerable to invasions by exotic plant species. Foliar traits, which in most cases presented significant phylogenetic signal, i.e. closely related species tended to resemble each other due to shared ancestry, separated invasive from native species. Invasive species had lower leaf mass per area and enhanced capacities in terms of productivity (photosynthetic capacity) and nutrient capture both of macro‐ (N, P, K) and microelements (Fe, Ni, Cu and Zn). All these differences remain highly significant after removing the effects of phylogenetic history. Alien‐invasive species did not show higher efficiency at using limiting nutrient resources, but they got faster leaf economics returns and occupied a different biogeochemical niche, which helps to explain the success of invasive plants and suggests that potential increases in soil nutrient availability might favor further invasive plant success.