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Recent modeling efforts have provided support for the importance of biotic interactions on individ- ual species distributions at macroecological scales (Araujo and Luoto 2007, Heikkinen et al. 2007), but whether these results are generally representa- tive of a wide range of species remains an open ques- tion. Associations between these factors may emerge based on life history traits or trophic status (Berg et al. 2010). For example, the ability of specialists to expand their ranges may be limited by the disper- sal ability of host or prey species, whereas generalist species will not face such constraints. Climate sensitivity may vary across trophic levels, with higher -level predator communities being more sensitive than producers (Voigt et al. 2003). This response may be due, at least in part, to differences in physiologic responses to climate change across trophic levels. For example, development rates of insects may be more sensitive to temperature than those of their plant food sources (Bale et al. 2002), resulting in increased herbivory intensity as a conse- quence of higher growth rates and reduced generation time in insect herbivores. In grasshoppers, changes in temperature influence resource acquisition, ultimate- ly affecting the intensity of intraspecific competition (Laws and Belovsky 2010). As responses to climate change become increasingly apparent across biologi- cal systems (Parmesan and Yohe 2003, Root et al. 2003), it may well be the range and variability of species- specific responses that poses the greatest chal- lenge to efforts to maintain ecological structure and function similar to that of present ecological systems. 7_23 "ol fec,/e, arP(l E cartY! ;t,errr Vr /rlerah///t,} Vulnerability refers to the degree to which an ecologi- cal community or individual species is likely to expe- rience harm due to exposure to perturbations or stresses. Species or ecosystem vulnerability to climate change is a function of three variables: exposure, or the degree to which a system or species is exposed to climate change and variability, sensitivity to these changes, and the species or ecosystems' adaptive capacity to respond to these changes as well as the strategies practitioners implement to help the species or system adapt (IPCC 2007, Williams et al. 2008). Specific factors that influence the vulnerability of species or ecosystems to climate change may include biological and physiological traits that make a species particularly sensitive to climate changes, the adap- tive capacity of the species, barriers to dispersal, high exposure or sensitivity to specific climate impacts because of distribution or biological factors, the pace and magnitude of climate change, or exposure to existing or future non - climate threats such as land use change. In a recent guide, Glick and Stein (20 10) provide an in -depth review and guidance on the use of vulnerability assessments in conservation planning. Exposure relates to short -term or long -term the degree of climate stress in a particular region. From a species or habitat perspective, exposure may include areas exposed to sea -level rise, or changes in precipitation and temperature. In some cases, local microhabitat buffering may reduce exposure. For example, some species may be buffered from climate changes by living in a thermally sheltered microhabi- tat under logs or in a cool ravine alongside a stream. Sensitivity is a measure of how a species or ecosystem responds or changes in relation to climatic condi- tions. Species or ecosystems that are more sensi- tive to changes in climate may experience dramatic shifts in distribution or population size in response to only slight increases or decreases in temperature and precipitation. Sensitivity will be determined by intrinsic factors including ecological, genetic and physiological traits (Table 1 -2). The combination of exposure and sensitivity deter- mine the potential impact of climate change on an ecosystem or species, which is then modified by the species' or ecosystem's adaptive capacity and the capacity of humans to manage, adapt and minimize climate change impacts (Williams et al. 2008). Adaptive capacity refers to the intrinsic