A trait-based approach to species’ roles in stream ecosystems: climate change, community structure, and material cycling
A trait-based approach to species’ roles in stream ecosystems: climate change, community structure, and material cycling
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基于性状的物种在河流生态系统中的作用的方法：气候变化、群落结构和物质循环
作者：
D. Spooner;C. Vaughn
栖息地质量和群落完整性的持续下降凸显了了解群落和环境变化如何相互作用地促进生态系统服务的重要性。我们进行了一项实验室实验，操纵驯化温度（5°C、15°C、25°C 和 35°C）对八种淡水贻贝物种提供的资源获取、同化和随后的生态系统服务的影响。我们的研究结果表明，尽管淡水贻贝被广泛归类为滤食性动物，但它们的热性能有明显的嵌套功能组（耐热和敏感）。在 35°C 时，耐热物种的资源同化能力增强，生态系统服务贡献率更高（养分排泄、底栖-中上层耦合）。相反，热敏感物种的同化率降低，并表现出一系列功能反应，包括增加/减少底栖-中上层耦合和营养物排泄。尽管热敏感物种在较高温度下可能处于较差的生理状况，但它们的生理反应可以对生态系统服务产生积极影响。我们将这些结果推断到物种组成不同的真实贻贝床，以解决群落组成的变化加上气候变化可能如何改变其贡献的生态服务。比较现场数据表明，两种共存、丰富且具有相反热性能的物种（韧带放线菌、褶皱放线菌）在群落生物量中占主导地位。此外，这些物种的相对比例不同的群落对生态系统服务的程度（底栖-中上层耦合）和质量（N:P排泄）有不同的影响。随着物种日益受到气候变化的威胁，应更加重视了解生理应激对生态系统完整性和功能的贡献。
The sustained decline in habitat quality and community integrity highlights the importance of understanding how communities and environmental variation interactively contribute to ecosystem services. We performed a laboratory experiment manipulating effects of acclimation temperature (5, 15, 25, and 35°C) on resource acquisition, assimilation and subsequent ecosystem services provided by eight freshwater mussel species. Our results suggest that although freshwater mussels are broadly categorized as filter feeders, there are distinct nested functional guilds (thermally tolerant and sensitive) associated with their thermal performance. At 35°C, thermally tolerant species have increased resource assimilation and higher rates of contributed ecosystem services (nutrient excretion, benthic–pelagic coupling). Conversely, thermally sensitive species have decreased assimilation rates and display an array of functional responses including increased/decreased benthic–pelagic coupling and nutrient excretion. Although thermally sensitive species may be in poorer physiological condition at warmer temperatures, their physiological responses can have positive effects on ecosystem services. We extrapolated these results to real mussel beds varying in species composition to address how shifts in community composition coupled with climate change may shift their contributed ecological services. Comparative field data indicate that two co-existing, abundant species with opposing thermal performance (Actinonaias ligamentina, Amblema plicata) differentially dominate community biomass. Additionally, communities varying in the relative proportion of these species differentially influence the magnitude (benthic–pelagic coupling) and quality (N:P excretion) of ecosystem services. As species are increasingly threatened by climate change, greater emphasis should be placed on understanding the contribution of physiological stress to the integrity and functioning of ecosystems.