Present, Future, and Novel Bioclimates of the San Francisco, California Region

Abstract

Bioclimates are syntheses of climatic variables into biologically relevant categories that facilitate comparative studies of biotic responses to climate conditions. Isobioclimates, unique combinations of bioclimatic indices (continentality, ombrotype, and thermotype), were constructed for northern California coastal ranges based on the Rivas-Martinez worldwide bioclimatic classification system for the end of the 20th century climatology (1971–2000) and end of the 21st century climatology (2070–2099) using two models, Geophysical Fluid Dynamics Laboratory (GFDL) model and the Parallel Climate Model (PCM), under the medium-high A2 emission scenario. The digitally mapped results were used to 1) assess the relative redistribution of isobioclimates and their magnitude of change, 2) quantify the loss of isobioclimates into the future, 3) identify and locate novel isobioclimates projected to appear, and 4) explore compositional change in vegetation types among analog isobioclimate patches. This study used downscaled climate variables to map the isobioclimates at a fine spatial resolution −270 m grid cells. Common to both models of future climate was a large change in thermotype. Changes in ombrotype differed among the two models. The end of 20th century climatology has 83 isobioclimates covering the 63,000 km2 study area. In both future projections 51 of those isobioclimates disappear over 40,000 km2. The ordination of vegetation-bioclimate relationships shows very strong correlation of Rivas-Martinez indices with vegetation distribution and composition. Comparisons of vegetation composition among analog patches suggest that vegetation change will be a local rearrangement of species already in place rather than one requiring long distance dispersal. The digitally mapped results facilitate comparison with other Mediterranean regions. Major remaining challenges include predicting vegetation composition of novel isobioclimates and developing metrics to compare differences in climate space.

Bioclimate of Italy: application of the worldwide bioclimatic classification system

“…These maps can be reproduced under future conditions, to monitor and quantify climate changes and the distribution of vegetation trends from the perspective of the WBCS. Indeed, the application of the WBCS at national, regional and local scales provides a multi-scale framework for the analysis of the responses of biotic systems to climate change (Rivas-Martínez et al, 2011;Torregrosa, Taylor, Flint, & Flint, 2013).…”

Bioclimate map of Sardinia (Italy)

“…Box, 1996;Ríos-Cornejo, del Río, & Penas, 2012), to perform habitat modeling (Guisan & Zimmerman, 2000) and to analyze vegetation dynamics, subsequently allowing the reconstruction of vegetation series and potential natural vegetation (Blasi, Filibeck, Frondoni, Rosati, & Smiraglia, 2004;Blasi et al, 2012;Farris, Filibeck, Marignani, & Rosati, 2010). Furthermore, bioclimatic models, focusing on climatic thresholds of species distributions, can predict the responses of living organisms to climate change (Huntley, Berry, Cramer, & McDonald, 1995;Pearson & Dawson, 2003;Walther, Berger, & Sykes, 2005) because integrated and biologically relevant combinations are better suited to exploring potential ecosystem response to changing climates than raw climate data (Torregrosa, Taylor, Flint & Flint, 2013). Many bioclimatic units, based on different classification methods and numerical criteria, have been defined by different authors, ranging from local to global application.…”

“…Formulated in the context of vegetation science, this classification was widely adopted in geobotany, landscape ecology (e.g. Fascetti, Pirone, & Rosati, 2013;Gavilán, Fernández-González, & Blasi, 1998;Rosati et al, 2010) and climate change studies (Torregrosa et al, 2013). Unfortunately, several applications of this classification are based on empiric expert based mapping procedures, failing with respect to reproducibility and updatability (e.g.…”

Spatial Interpolation of Ewert’s Index of Continentality in Poland

“…For Poland, such analyses have been performed by Marciniak (1986, 1992), Ko_ zuchowski and Wibig (1988), and Ko_ zuchowski (2003). Recently, continentality indices have been applied in environmental analyses, particularly as a variable supporting the analysis of variability and spatial distribution of, e.g., air temperature (Hogewind and Bissolli 2011), evapotranspiration (Marti and Gasque 2010) and bioclimatic changes (Torregrosa et al 2013). The analytical usefulness of continentality indices has also been corroborated in the investigations of glacier mass balance (Holmlund and Schneider 1997), plant species range and the treeline (Caccianiga et al 2008), and plant pollen in northern Europe (Salonen et al 2012).…”

“…In recent studies, index maps are generated in the GIS environment, taking advantage of raster maps and showing more details (Mikolášková 2009;Torregrosa et al 2013). The spatialization approaches applied are relatively simple, one-dimensional, and disregard selection of an optimal interpolation method and accuracy of the results.…”