CFE agenda 091117 - Laserfiche WebLink

Browse Search

ability of organisms to adapt to changing condi- tions. Species or ecosystems with a high degree of adaptive capacity to climate changes will be less impacted than species or ecosystems with relatively low adaptive capacity, even if they are sensitive to climate change. Ecological plasticity, or the abil- ity individuals to modify their behavior, morphol- ogy, or physiology to changing conditions, generally increases the likelihood that a species will be able to respond to climate change impacts (Parmesan et al. 2005). In addition, evolutionary processes have the potential to influence responses to climate change, but require genetic change over multiple genera- tions. Genetic change in response to recent, rapid climate change has been documented in a number of species, over differing time scales and to differing degrees (reviewed in Bradshaw and Holzapfel 2006). However, the majority of species will not likely have the capacity to adapt given the rate and magnitude of projected climate changes (Bradshaw and Holza- pfel 2006, Williams et al. 2008). Evidence from the fossil record suggests that, despite evidence for local adaptation at specific sites, species as a whole tend to shift their geographical distributions in response to climate change, rather than undergoing major evolu- tion at the species level that would allow conserva- tion of the original range (Parmesan 2006). Vulnerability assessments that are geared towards quantifying the relative exposure and sensitivity to climate changes as well as the adaptive capacity of species or ecosystems can help to direct and prioritize research and management efforts. Because vulner- ability assessments can be time - intensive and expen- sive, selecting specific species or ecosystem targets can be challenging and will depend on the manager's needs or an organization's values. If only a subset of species or habitats can be chosen, these targets Table 1 -2. Physiological and life - history traits that influence species vulnerability in response to climate change disturbances (Source: Steffen et al. 2009, (DCommonwealth of Australia, used with permission). • Physiological tolerance to broad range of factors such as tempertures, water availability and fire • High degree of phenotypic plasticity • High degree of genetic variability • Short generation times (rapid life cycles) and short time to sexual maturity • High fecundity • 'Genera list'req uirements for food, nesting sites, etc. • Good dispersal capability • Broad geographic ranges • Narrow range of physiological tolerance to factors such as temperature, water availability and fire • Low genetic variability • Long generation times and long time to sexual maturity • Specialized requirements for other species (e.g. for a disperser, prey species, pollinator or photosynthetic symbiont) or for a particular habitat that may itself be restricted (e.g. a particular soil type) • Poor dispersers • Narrow geographic ranges