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首页> 外文期刊>San Francisco Estuary and Watershed Science >A Place to Call Home: A Synthesis of Delta Smelt Habitat in the Upper San Francisco Estuary
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A Place to Call Home: A Synthesis of Delta Smelt Habitat in the Upper San Francisco Estuary

机译：回家的地方：旧金山河口上游的三角洲冶炼栖息地综合报告

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We used a combination of published literature and field survey data to synthesize the available information about habitat use by delta smelt Hypomesus transpacificus, a declining native species in the San Francisco Estuary. Delta smelt habitat ranges from San Pablo and Suisun bays to their freshwater tributaries, including the Sacramento and San Joaquin rivers. In recent years, substantial numbers of delta smelt have colonized habitat in Liberty Island, a north Delta area that flooded in 1997. The species has a more upstream distribution during spawning as opposed to juvenile rearing periods. Post-larvae and juveniles tend to have a more downstream distribution during wetter years. Delta smelt are most common in low-salinity habitat (12 NTU) and moderate temperatures (7?°C to 25 °C). They do not appear to have strong substrate preferences, but sandy shoals are important for spawning in other osmerids. The evidence to date suggests that they generally require at least some tidal flow in their habitats. Delta smelt also occur in a wide range of channel sizes, although they seem to be rarer in small channels (<15 m wide). Nonetheless, there is some evidence that open water adjacent to habitats with long water-residence times (e.g. tidal marsh, shoal, low-order channels) may be favorable. Other desirable features of delta smelt habitat include high calanoid copepod densities and low levels of submerged aquatic vegetation (SAV) and the toxic algae Microcystis. Although enough is known to plan for large-scale pilot habitat projects, these efforts are vulnerable to several factors, most notably climate change, which will change salinity regimes and increase the occurrence of lethal temperatures. We recommend restoration of multiple geographical regions and habitats coupled with extensive monitoring and adaptive management. An overall emphasis on ecosystem processes rather than specific habitat features is also likely to be most effective for recovery of the species.
机译：我们结合了已发表的文献资料和现场调查数据，综合了三角洲冶炼的Hypomesus transpacificus（一种在旧金山河口逐渐减少的本地物种）的栖息地利用信息。三角洲的冶炼栖息地范围从圣巴勃罗和Suisun海湾到其淡水支流，包括萨克拉曼多和圣华金河。近年来，大量的三角洲熔体已经定居在自由岛上，该岛是1997年洪水泛滥的北部三角洲地区。该物种在产卵期的上游分布较幼年时期为多。幼年和幼年在较湿润的年份倾向于向下游分布。三角洲冶炼最常见于低盐度生境（12 NTU）和中等温度（7？C至25°C）。它们似乎对底物没有强烈的偏好，但是沙质浅滩对于产其他鱼很重要。迄今为止的证据表明，它们通常在其栖息地中至少需要一定的潮流。三角洲冶炼也出现在各种渠道规模中，尽管在小渠道（<15 m宽）中似乎很少见。但是，有一些证据表明，靠近保水时间长的栖息地（例如潮汐沼泽，浅滩，低阶河道）的开阔水域可能是有利的。三角洲冶炼栖息地的其他理想特征包括：高cal足类co足类密度和低水平的水下水生植物（SAV）和有毒藻类微囊藻。尽管已知有足够的计划大规模试点栖息地项目，但这些努力容易受到多种因素的影响，最明显的是气候变化，这将改变盐度制度并增加致命温度的发生。我们建议恢复多个地理区域和栖息地，并进行广泛的监控和适应性管理。全面强调生态系统过程而不是特定的栖息地特征也可能最有效地恢复物种。

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