科研之友
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摘要
Many lotic ecosystems are spatially and temporally heterogeneous but none more so than dryland streams flowing through arid and semi-arid landscapes. Understanding seasonal variation in richness and trait composition is critical to our fundamental understanding of these dynamic stream networks. Here, we analyzed aquatic macroinvertebrate communities within perennial and intermittent reaches in replicate dryland watersheds in southwestern USA across 10 seasons and 4 years. We quantified how hydrology, season, and microhabitat type affected taxa richness and trait composition. Taxa richness was higher in perennial than intermittent reaches, in pools than riffles, and in fall and summer than in spring. The interaction between hydrology and season was important; the difference between fall high and spring low richness was greater in intermittent than perennial streams. Hydrology was the main predictor of trait composition; intermittent streams supported a larger fraction of small taxa, taxa with the ability to undergo diapause, and uni- or multivoltine taxa (i.e., taxa with shorter life cycles). Trait composition did not vary across seasons among perennial reaches whereas the fraction of aerial dispersers appeared to be greater in spring than other seasons among intermittent reaches. Our results were largely consistent with predictions of the habitat templet; r-selected traits were more frequently represented in intermittent communities. The temporal characterization of macroinvertebrate community structure in dryland streams provides a powerful glimpse of how stream communities may respond to a drying climate.
- 出版日期2017-7
