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Tits A %pate re's it ' ld d tvl dMiFfilee"S VI&V tffl.UWra lzasuwll qn a ftrw ftrg iwctf" , M"M "I bic,twl, Bilrws. dF4 rro, w W41 011,1w d" f',1*J,00,0 Map a V8 h1thO, MAW tiiAbd9't„ EslablishrrIonit gnu Wmc "' 0 pr o e !w 0,#e d �Yl�wr'kl�m{YIY�d"�Wiepgt �NNuu�'alil��aNIRVI�` NIPI,y,; ro,putAuclivo nt&as. I� m 4�YI iq u" Ifrm;��ONir� �"miufil�k��rul�ir�Yt� r n, Figure 4 -18. The four stages of invasion and the factors affecting non - native (nonindigenous) plant species (NIPS) success at each stage. The same processes control invasive animal and disease introductions, and could apply to native species that become invasive as a result of range expansion under climate change (Source: Thecharides and Dukes 2007, © Wiley InterScience, used with permission). Under climate change, current climatic constraints that limit some species' ability to spread will be reduced such that previously benign non - native or current invasive species may pose new or altered threats (Hellmann et al. 2008). Such constraints include factors limiting the length of the grow- ing season, temperature requirements for peri- ods of dormancy, or moisture tolerances. Warmer temperatures or changes in precipitation may alter these constraints, thereby changing the competitive interactions between native and non - native species. Those species tolerant of high temperatures, drought conditions, or more frequent disturbances may do particularly well under climate change. For exam- ple, in the Great Lakes region, populations of the common reed (Phragmites australis), which is listed as a severe threat in North Carolina, expanded with higher than average temperatures and declines in water levels (Wilcox et al. 2003). Further warm- ing and /or increased drought may give this species an advantage over native marsh species, especially in disturbed environments. Climate change may affect the population densi- ties of some invasive species, thereby altering their impact on native species within their current range (Hellman et al. 2008). For example, colder winter temperatures are associated with lower reproduc- tive activity and lower overwinter survival in nutria (Willner et al. 1979). Already, nutria have signifi- cant impacts on wetland vegetation (Fuller et al. 1984, Taylor and Grace 1995, Evers et al. 1998), and projected increases in winter temperatures could favor overwinter survival and increased reproductive rates, resulting in additional herbivory pressure on marsh communities. Many of the traits that allow rapid colonization and establishment in invasive species are the same traits that make a species least at risk to climate change (see Table 1 -2). Native species may have the potential to become invasive when they spread into new locations as a result climate change (Mueller and Hellmann 2008). One example is the mountain pine beetle (Dendroctonus ponderosae). Historically, the range of the mountain pine beetle has been limited by cold temperatures at higher altitudes and latitudes that prevent the beetle from completing its life cycle in a single season. However, warmer temperatures in recent years have allowed the beetle to complete its life cycle in a single season. The resulting expansion in the beetle's range