10 research outputs found
A New Tool for Exploring Climate Change Induced Range Shifts of Conifer Species in China
<div><p>It is inevitable that tree species will undergo considerable range shifts in response to anthropogenic induced climate change, even in the near future. Species Distribution Models (SDMs) are valuable tools in exploring general temporal trends and spatial patterns of potential range shifts. Understanding projections to future climate for tree species will facilitate policy making in forestry. Comparative studies for a large number of tree species require the availability of suitable and standardized indices. A crucial limitation when deriving such indices is the threshold problem in defining ranges, which has made interspecies comparison problematic until now. Here we propose a set of threshold-free indices, which measure range explosion (I), overlapping (O), and range center movement in three dimensions (Dx, Dy, Dz), based on fuzzy set theory (Fuzzy Set based Potential Range Shift Index, F-PRS Index). A graphical tool (PRS_Chart) was developed to visualize these indices. This technique was then applied to 46 Pinaceae species that are widely distributed and partly common in China. The spatial patterns of the modeling results were then statistically tested for significance. Results showed that range overlap was generally low; no trends in range size changes and longitudinal movements could be found, but northward and poleward movement trends were highly significant. Although range shifts seemed to exhibit huge interspecies variation, they were very consistent for certain climate change scenarios. Comparing the IPCC scenarios, we found that scenario A1B would lead to a larger extent of range shifts (less overlapping and more latitudinal movement) than the A2 and the B1 scenarios. It is expected that the newly developed standardized indices and the respective graphical tool will facilitate studies on PRS's for other tree species groups that are important in forestry as well, and thus support climate adaptive forest management.</p></div
PRS_Chart for <i>Picea</i>.
<p>The same as legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098643#pone-0098643-g003" target="_blank">Figure 3</a> except the species number is for <i>Picea</i>.</p
Performance of SDM modeling measured by model evaluation indices.
<p>Notes: Table content is means and standard deviations of model evaluation indices of species distribution model (SDM) aggregated from all combinations species within the genra and climate scenarios (A1B, A2, and B1). <b>AUC</b> is area under the receiver operating characteristic curve. <b>Max TSS</b> is maximum true skill score. <b>Max </b><b><i>κ</i></b> is maximum Kappa value.</p><p>Performance of SDM modeling measured by model evaluation indices.</p
Species distributions and environmental layers.
<p>Figure (a–d) are distribution maps of species pooled to genera <i>Pinus</i>, <i>Abies</i>, <i>Larix</i> and <i>Picea</i>, respectively, superimposed over background digital elevation model (DEM) maps with 50% transparence. Figure (e) and (f) are maps of the environmental factors gross degree days (GDD) and aridity respectively.</p
PRS_Chart for <i>Abies</i>.
<p>Each chart is a Potential range shift chart (PRS_Chart) that is explained in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098643#pone-0098643-g002" target="_blank">Figure 2</a>. Charts in the tabular style figure representing combinations of species (SP1-12) in <i>Abies</i> and climate scenarios (A1B, A2, and B1). General species information can be found in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098643#pone.0098643.s004" target="_blank">Table S1</a>.</p
PRS_Chart for <i>Pinus</i>.
<p>The same as legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098643#pone-0098643-g003" target="_blank">Figure 3</a> except the species number is for <i>Pinus</i>.</p
Comparisons of Potential range shift (PRS) indices among climate scenarios.
<p>otes: The table contents after row <b>ANOVA</b> are results of analysis of variance for each genus comparing among climate scenarios, in which X representing not significant (α = 0.05) or P-values is provided significant. Contents after row <b>A1B</b>, <b>A2</b>, and <b>B1</b> are results of multiple comparisons if the ANOVA result is significant by using least significant difference t test (LSD-t). the/means test is not carried out. Number and superscript represent mean value and multiple comparison result, with same superscript characters meaning not significant and different character meaning significant (α = 0.10).</p><p>Comparisons of Potential range shift (PRS) indices among climate scenarios.</p
PRS_Chart for <i>Larix</i>.
<p>The same as legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098643#pone-0098643-g003" target="_blank">Figure 3</a> except the species number is for <i>Larix</i>.</p
PRS_Chart and an example for <i>Pinus koraiensis</i>.
<p>Figure (a) is an example potential range shift chart (PRS_Chart) to visualize PRS indices. A unit circle (with thin black continuous line) was used to represent current distribution area for the focal species, and another circle (with broad blue broken line) with radium proportional to the ratio of distribution areas between current and projected future distributions was used to represent future distribution area. A sector of the unit circle (in red) with proportional area equal to the <b>O</b> value was used to represent range overlapping. <b>Dx</b> and <b>Dy</b> combined were represented by a directional arrow line (in blue). The distance and direction of vertical movement of range center (<b>Dz</b>) was represented by a vertical arrow (in black). Figure (b) are maps and PRS_Charts that served as an example for spices <i>Pinus koraiensis</i>. Maps in first row are potential range maps for climate scenario A1B (in the end of this century), current climate, and B1, respectively. The map in the middle of second row is digital elevation map, and charts in the left and right are PRS_Charts for A1B and A2 respectively. The values listed in bottom row are values of the PRS indices for A1B and B1.</p
Statistics of potential range shift indices.
<p>Notes: Table contents are mean(<b>mean</b>) and standard deviation (<b>Std</b>) of potential range shift (PRS) indices representing by combinations of <b>I</b>, <b>O</b>, <b>Dx</b>, <b>Dy</b>, <b>Dz</b> and CO<sub>2</sub> emission scenarios <b>A1B</b>, <b>A2</b>, and <b>B1</b> shown in first two columns. Superscripts ** after mean values indicating that the mean is very significant from zero (α = 0.01), and * is significant different from zero (α = 0.05) by using double sided student distribution. No superscript after mean value means it is not significant from zero, except the mean of O index which did not test for deviation from zero.</p><p>Statistics of potential range shift indices.</p