Appendix A. A figure showing landscape level Moran's Istd correlograms of (a) native and (b) nonnative (log-transformed) plant species richness, and residuals from (c) native and (d) nonnative plant species richness models.

A figure showing landscape level Moran's Istd correlograms of (a) native and (b) nonnative (log-transformed) plant species richness, and residuals from (c) native and (d) nonnative plant species richness models

Variables and their relative contribution in the final MaxEnt model.

<p>¹ percent contribution is calculated as the increase in regularized gain added to the contribution of the corresponding variable for each of the 5000 iterations of the model (subtracted if the change to the absolute value of lambda is negative).</p><p>Variables and their relative contribution in the final MaxEnt model.</p

Comparison of mean annual temperature (MAT) at three spatial resolutions (4 km, 1 km, and 90 m) for climate normals 1981–2010 in Rocky Mountain National Park, Colorado.

<p>Data Sources: PRISM Climate Group (<a href="http://www.prism.oregonstate.edu/" target="_blank">http://www.prism.oregonstate.edu/</a>) WorldClim (<a href="http://www.worldclim.org/" target="_blank">http://www.worldclim.org/</a>) and ClimateWNA (<a href="http://climatewna.com/" target="_blank">http://climatewna.com/</a>).</p

Using High-Resolution Future Climate Scenarios to Forecast <i>Bromus tectorum</i> Invasion in Rocky Mountain National Park

<div><p>National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. <i>Bromus tectorum</i> L. (commonly called downy brome or cheatgrass), which is found in Rocky Mountain National Park (hereafter, the Park), Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil nitrogen, altered nutrient and hydrologic regimes, and increased fire intensity. We estimated the potential distribution of <i>B. tectorum</i> in the Park based on occurrence records (n = 211), current and future climate, and distance to roads and trails. An ensemble of six future climate scenarios indicated the habitable area of <i>B. tectorum</i> may increase from approximately 5.5% currently to 20.4% of the Park by the year 2050. Using ordination methods we evaluated the climatic space occupied by <i>B. tectorum</i> in the Park and how this space may shift given future climate change. Modeling climate change at a small extent (1,076 km2) and at a fine spatial resolution (90 m) is a novel approach in species distribution modeling, and may provide inference for microclimates not captured in coarse-scale models. Maps from our models serve as high-resolution hypotheses that can be improved over time by land managers to set priorities for surveys and removal of invasive species such as <i>B. tectorum</i>.</p></div

Variable contribution to training gain (a) and area under curve (b).

<p>Gray bars indicate how well the model performs with only that variable, versus a full model. Values shown are averaged over 100 replicate MaxEnt model runs.</p

<i>Bromus tectorum</i> current suitable habitat in Rocky Mountain National Park (a) and increasing, decreasing, stable, and unsuitable habitat for the year 2050 (b) based on MaxEnt model outputs.

<p>Elevation has been included for reference (coordinate system NAD 1983 UTM Zone 13 N).</p

Principle component analysis (PCA) of niche overlap (blue) for <i>B</i>. <i>tectorum</i> in Rocky Mountain National Park based on current (green) and future (red) climate space.

<p>Averages for five climatic variables from six global circulation models (GCMs) were included in this analysis: mean annual temperature, spring degree days below 18°C, beginning of frost-free period, mean summer (May-Sept.) precipitation, and continentality (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0117893#sec002" target="_blank">methods</a> for description of GCMs).</p

Appendix A. Geographic location, vegetation, soil, and disturbance level for each 1000 m2 plot in the study area.

Geographic location, vegetation, soil, and disturbance level for each 1000 m2 plot in the study area