Dataset from Habitat loss, predation pressure and episodic heat-shocks interact to impact arthropods and photosynthetic functioning of microecosystems

Ecosystems face multiple, potentially interacting, anthropogenic pressures that can modify biodiversity and ecosystem functioning. Using a bryophyte–microarthropod microecosystem we tested the combined effects of habitat loss, episodic heat-shocks and an introduced non-native apex predator on ecosystem function (chlorophyll fluorescence as an indicator of photosystem II function) and microarthropod communities (abundance and body size). The photosynthetic function was degraded by the sequence of heat-shock episodes, but unaffected by microecosystem patch size or top-down pressure from the introduced predator. In small microecosystem patches without the non-native predator, Acari abundance decreased with heat-shock frequency, while Collembola abundance increased. These trends disappeared in larger microecosystem patches or when predators were introduced, although Acari abundance was lower in large patches that underwent heat-shocks and were exposed to the predator. Mean assemblage body length (Collembola) was reduced independently in small microecosystem patches and with greater heat-shock frequency. Our experimental simulation of episodic heat waves, habitat loss and non-native predation pressure in microecosystems produced evidence of individual and potentially synergistic and antagonistic effects on ecosystem function and microarthropod communities. Such complex outcomes of interactions between multiple stressors need to be considered when assessing anthropogenic risks for biota and ecosystem functioning.

生态系统面临多种潜在交互作用的人为胁迫因子，这些因子可改变生物多样性与生态系统功能。本研究以苔藓植物-微型节肢动物微生态系统（bryophyte–microarthropod microecosystem）为实验模型，探究了生境丧失、间歇性热冲击以及外来顶级捕食者三者对生态系统功能（以叶绿素荧光作为光系统II（photosystem II）功能的指示指标）与微型节肢动物群落（包括种群丰度与个体体型）的联合影响。研究结果表明，光合功能会因一系列间歇性热冲击事件而受损，但不受微生态系统斑块大小或外来捕食者带来的下行调控压力的影响。在无外来捕食者的小型微生态系统斑块中，螨类（Acari）丰度随热冲击频率升高而降低，而弹尾虫（Collembola）丰度则随之升高；这类变化趋势在大型微生态系统斑块或存在捕食者的情况下会消失，不过在经历热冲击且暴露于捕食者的大型斑块中，螨类丰度仍处于较低水平。弹尾虫群落的平均个体体长会因小型微生态系统斑块环境以及更高的热冲击频率而独立降低。本研究通过对微生态系统中的间歇性热浪、生境丧失与外来捕食胁迫进行实验模拟，证实了多种胁迫因子对生态系统功能及微型节肢动物群落存在单独作用以及潜在的协同与拮抗效应。在评估人为活动对生物群落及生态系统功能带来的风险时，需考虑这类多胁迫因子交互作用产生的复杂结果。