Cross-Scale Assessment of Potential Habitat Shifts in a Rapidly Changing Climate

• Published in: Invasive plant science and management 2014-07, Vol.7 (3), p.491-502
• Main Authors: Jarnevich, Catherine S, Holcombe, Tracy R, Bella, Elizabeth M, Carlson, Matthew L, Graziano, Gino, Lamb, Melinda, Seefeldt, Steven S, Morisette, Jeffery
• Format: Article
• Language: English
• Subjects: Alaska; Anthropogenic factors; bioclimatic modeling; Centaurea stoebe; Cirsium arvense; Climate change; Climatic data; Ecosystems; Fallopia japonica (Polygonum cuspidatum) complex; General circulation models; Habitats; Invasive plants; invasive species; Melilotus albus; Nonnative species; Phalaris arundinacea; Plant species; Scale models; Variables
• ISSN: 1939-7291; 1939-747X
• DOI: 10.1614/IPSM-D-13-00071.1

We assessed the ability of climatic, environmental, and anthropogenic variables to predict areas of high-risk for plant invasion and consider the relative importance and contribution of these predictor variables by considering two spatial scales in a region of rapidly changing climate. We created predictive distribution models, using Maxent, for three highly invasive plant species (Canada thistle, white sweetclover, and reed canarygrass) in Alaska at both a regional scale and a local scale. Regional scale models encompassed southern coastal Alaska and were developed from topographic and climatic data at a 2 km (1.2 mi) spatial resolution. Models were applied to future climate (2030). Local scale models were spatially nested within the regional area; these models incorporated physiographic and anthropogenic variables at a 30 m (98.4 ft) resolution. Regional and local models performed well (AUC values > 0.7), with the exception of one species at each spatial scale. Regional models predict an increase in area of suitable habitat for all species by 2030 with a general shift to higher elevation areas; however, the distribution of each species was driven by different climate and topographical variables. In contrast local models indicate that distance to right-of-ways and elevation are associated with habitat suitability for all three species at this spatial level. Combining results from regional models, capturing long-term distribution, and local models, capturing near-term establishment and distribution, offers a new and effective tool for highlighting at-risk areas and provides insight on how variables acting at different scales contribute to suitability predictions. The combinations also provides easy comparison, highlighting agreement between the two scales, where long-term distribution factors predict suitability while near-term do not and vice versa. Nomenclature: Canada thistle, Cirsium arvense (L.) Scop., reed canarygrass, Phalaris arundinacea L, white sweetclover, Melilotus albus Medik. Management Implications: Effective and proactive management of invasive species requires information on both current and potential future distributions. Alaska, similar to other high latitude areas, is relatively invasion free (Lassuy and Lewis, 2013). The rapidly changing climate in this region, however, is expected to increase the area suitable for establishment for a larger number of invasive species. Here, we present results for habitat suitability models of highly i