Scrine Jennifer, Jochum Malte, Ólafsson Jón S, O'Gorman Eoin J
Imperial College London Silwood Park Campus Buckhurst Road, Ascot Berkshire SL5 7PY UK.
Institute of Plant Sciences University of Bern Bern Switzerland.
Ecol Evol. 2017 Oct 6;7(22):9333-9346. doi: 10.1002/ece3.3412. eCollection 2017 Nov.
Warming can lead to increased growth of plants or algae at the base of the food web, which may increase the overall complexity of habitat available for other organisms. Temperature and habitat complexity have both been shown to alter the structure and functioning of communities, but they may also have interactive effects, for example, if the shade provided by additional habitat negates the positive effect of temperature on understory plant or algal growth. This study explored the interactive effects of these two major environmental factors in a manipulative field experiment, by assessing changes in ecosystem functioning (primary production and decomposition) and community structure in the presence and absence of artificial plants along a natural stream temperature gradient of 5-18°C. There was no effect of temperature or habitat complexity on benthic primary production, but epiphytic production increased with temperature in the more complex habitat. Cellulose decomposition rate increased with temperature, but was unaffected by habitat complexity. Macroinvertebrate communities were less similar to each other as temperature increased, while habitat complexity only altered community composition in the coldest streams. There was also an overall increase in macroinvertebrate abundance, body mass, and biomass in the warmest streams, driven by increasing dominance of snails and blackfly larvae. Presence of habitat complexity, however, dampened the strength of this temperature effect on the abundance of macroinvertebrates in the benthos. The interactive effects that were observed suggest that habitat complexity can modify the effects of temperature on important ecosystem functions and community structure, which may alter energy flow through the food web. Given that warming is likely to increase habitat complexity, particularly at higher latitudes, more studies should investigate these two major environmental factors in combination to improve our ability to predict the impacts of future global change.
气候变暖会导致食物网底层的植物或藻类生长加快，这可能会增加可供其他生物生存的栖息地的整体复杂性。温度和栖息地复杂性都已被证明会改变群落的结构和功能，但它们也可能产生交互作用，例如，如果额外栖息地提供的遮蔽抵消了温度对林下植物或藻类生长的积极影响。本研究通过评估在5-18°C的自然溪流温度梯度下，有无人工植物时生态系统功能（初级生产和分解）及群落结构的变化，在一项可控的田间实验中探究了这两个主要环境因素的交互作用。温度或栖息地复杂性对底栖初级生产没有影响，但在更复杂的栖息地中，附生植物的产量随温度升高而增加。纤维素分解速率随温度升高而增加，但不受栖息地复杂性的影响。随着温度升高，大型无脊椎动物群落彼此之间的相似度降低，而栖息地复杂性仅在最冷的溪流中改变了群落组成。在最温暖的溪流中，由于蜗牛和蚋幼虫的优势度增加，大型无脊椎动物的丰度、体重和生物量总体上也有所增加。然而，栖息地复杂性的存在减弱了这种温度效应对底栖大型无脊椎动物丰度的影响。观察到的交互作用表明，栖息地复杂性可以改变温度对重要生态系统功能和群落结构的影响，这可能会改变通过食物网的能量流动。鉴于气候变暖可能会增加栖息地复杂性，尤其是在高纬度地区，更多的研究应该综合调查这两个主要环境因素，以提高我们预测未来全球变化影响的能力。
