Data_Sheet_1_Tree growth at the limits: the response of multiple conifers to opposing climatic constraints along an elevational gradient in the Alps.docx

IntroductionClimate change affects the vitality of mountain forests through increasing temperatures and decreasing water availability due to changing precipitation patterns, earlier snowmelt, and increasing evaporative demand. Depending on species characteristics, tree growth might therefore increase in cold habitats near the forest line but decrease in water-limited conditions at low elevation.MethodsWe analyzed the tree-ring widths of five conifers (Picea abies, Larix decidua, Pinus sylvestris, Pinus nigra, and Pinus cembra) along an elevational gradient from 1,000 m to 2,320 m above sea level (a.s.l.) in Vinschgau/Val Venosta Valley in Northern Italy, one of the driest regions of the Alps (mean annual precipitation of 682 mm at 1,310 m a.s.l.).ResultsOur aim was to estimate the species-specific growth response to changing climate conditions along an elevational gradient. At low elevations, we observed a significant response to water availability not only during the actual growing season but also throughout the previous autumn for all species present. At mid-elevation, the correlation coefficients to precipitation and drought indices (SPEI) were highest for Picea abies. At high elevations, the positive correlation of growth with temperature was smaller than expected for Pinus cembra. In contrast, Larix decidua responded positively to temperature and grew faster in recent decades.DiscussionConsidering that a further increase in temperatures will reduce plant water availability during the growing season, our space-for-time approach provides an outlook on future growth conditions of conifers in larger regions of the European Alps. Water limitation will affect tree growth and vitality not only at low elevation in the valleys but also at mid elevation on mountain slopes, potentially impacting timber production and protective and recreative functions of forests. Near the forest line, the different capabilities of tree species to benefit from higher temperatures might lead to changes in species composition.</p

On the Effects of Scale for Ecosystem Services Mapping

<div><p>Ecosystems provide life-sustaining services upon which human civilization depends, but their degradation largely continues unabated. Spatially explicit information on ecosystem services (ES) provision is required to better guide decision making, particularly for mountain systems, which are characterized by vertical gradients and isolation with high topographic complexity, making them particularly sensitive to global change. But while spatially explicit ES quantification and valuation allows the identification of areas of abundant or limited supply of and demand for ES, the accuracy and usefulness of the information varies considerably depending on the scale and methods used. Using four case studies from mountainous regions in Europe and the U.S., we quantify information gains and losses when mapping five ES - carbon sequestration, flood regulation, agricultural production, timber harvest, and scenic beauty - at coarse and fine resolution (250 m vs. 25 m in Europe and 300 m vs. 30 m in the U.S.). We analyze the effects of scale on ES estimates and their spatial pattern and show how these effects are related to different ES, terrain structure and model properties. ES estimates differ substantially between the fine and coarse resolution analyses in all case studies and across all services. This scale effect is not equally strong for all ES. We show that spatially explicit information about non-clustered, isolated ES tends to be lost at coarse resolution and against expectation, mainly in less rugged terrain, which calls for finer resolution assessments in such contexts. The effect of terrain ruggedness is also related to model properties such as dependency on land use-land cover data. We close with recommendations for mapping ES to make the resulting maps more comparable, and suggest a four-step approach to address the issue of scale when mapping ES that can deliver information to support ES-based decision making with greater accuracy and reliability.</p></div

Moran’s I for all case study areas and ES at fine and coarse resolution plotted against lag distance classes of 500 m.

<p>Indicated on the x-Axis is the upper distance of each lag.</p

Absolute difference in coverage (%) between fine and coarse resolution LULC classification.

<p>+ and – indicate over- and underestimation at the coarse resolution.</p

Box- and Whisker plots of land use classes (x-Axis) and ES values (y-Axis) for fine resolution timber production.

<p>Box- and Whisker plots of land use classes (x-Axis) and ES values (y-Axis) for fine resolution timber production.</p

Absolute difference between coarse and fine resolution ES values (%) for all ES and case study areas.

<p>Absolute difference between coarse and fine resolution ES values (%) for all ES and case study areas.</p

TRI values and location of case study areas (world map: [103]).

<p>TRI values and location of case study areas (world map: <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112601#pone.0112601-LP1" target="_blank">[103]</a>).</p