基于特征的方法评估环境脆弱性的吸引力来自于它们对人口和社区结构变化的潜在机制的潜在洞察力。特征可以为观察到的对环境变化的反应提供基于生态的解释,以及通过发展特征和环境变量之间的关系获得的预测能力。尽管有这些潜在的好处,关于这些方法的效用和局限性仍然存在问题,我们探讨的重点是以下问题:(a)基于单性状-环境关系的生物响应对变化条件的预测有多可靠?(b)哪些因素限制了单性状-环境关系的检测,以及如何解决这些问题?(c)我们是否可以使用有关元社区过程的信息来揭示未满足基于特征的研究假设的条件?我们通过回顾发表的有关河流生态系统中水生无脊椎动物群落的文献来解决这些问题。我们的发现有助于定义影响基于特征的方法在解决复杂,气候变化对河流生态系统水文和热力状况的多方面影响。关键结论是,观察到的特征和环境压力源之间的关系通常与从当前基于特征的思维中得出的预定义假设不一致,特别是与单一特征-环境关系有关。可以影响基于性状的评估结果的因素包括性状之间和环境变量之间的相互关系,空间尺度,生物相互作用的强度,栖息地干扰的强度,非生物胁迫的程度,和性状表征的方法。为解决这些问题,提出了一些建议,供实践和进一步研究,包括使用系统发育相关性来解决相互关联。在适当考虑这些问题的情况下,基于特征的生物对环境变化的脆弱性评估可以成为保护未来受威胁人群的有用工具。
The appeal of trait-based approaches for assessing environmental vulnerabilities arises from the potential insight they provide into the mechanisms underlying the changes in populations and community structure. Traits can provide ecologically based explanations for observed responses to environmental changes, along with predictive power gained by developing relationships between traits and environmental variables. Despite these potential benefits, questions remain regarding the utility and limitations of these approaches, which we explore focusing on the following questions: (a) How reliable are predictions of biotic responses to changing conditions based on single trait-environment relationships? (b) What factors constrain detection of single trait-environment relationships, and how can they be addressed? (c) Can we use information on meta-community processes to reveal conditions when assumptions underlying trait-based studies are not met? We address these questions by reviewing published literature on aquatic invertebrate communities from stream ecosystems. Our findings help to define factors that influence the successful application of trait-based approaches in addressing the complex, multifaceted effects of changing climate conditions on hydrologic and thermal regimes in stream ecosystems. Key conclusions are that observed relationships between traits and environmental stressors are often inconsistent with predefined hypotheses derived from current trait-based thinking, particularly related to single trait-environment relationships. Factors that can influence findings of trait-based assessments include intercorrelations of among traits and among environmental variables, spatial scale, strength of biotic interactions, intensity of habitat disturbance, degree of abiotic stress, and methods of trait characterization. Several recommendations are made for practice and further study to address these concerns, including using phylogenetic relatedness to address intercorrelation. With proper consideration of these issues, trait-based assessment of organismal vulnerability to environmental changes can become a useful tool to conserve threatened populations into the future.