Fires are a common feature of many landscapes, with numerous and complex ecological consequences. In stream ecosystems, fire can strongly influence fluvial geomorphic characteristics and riparian vegetation, which are structural components of stream–riparian ecosystems that contribute to biodiversity and ecosystem function. However, the effects of fire severity on stream–riparian ecosystems in California’s Sierra Nevada region (USA) are not well described, yet critical for effectively informing fire management and policy. At 12 stream reaches paired by fire severity (one high-severity burned, one low-severity burned), no significant differences were found in riparian plant community cover and composition or stream geomorphic characteristics 2–15 years following wildfire. In addition, minimal changes in riparian vegetation and stream geomorphic properties were observed in the first summer following the extensive and severe Rim Fire. However, an upstream-to-downstream influence of multiple fire occurrences was observed over the previous 81 years within each catchment on stream geomorphic metrics, including sediment size, embeddedness and channel geometry, at our study reaches. The inconsistent effects of wildfire on stream–riparian vegetation and geomorphic characteristics over space and time may be related to time since fire and precipitation.

中文翻译：

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野火严重程度对美国加利福尼亚州内华达山脉森林溪流地貌特征和河岸植被的影响

火灾是许多景观的共同特征，具有众多复杂的生态后果。在河流生态系统中，火可以强烈影响河流地貌特征和河岸植被，它们是河流-河岸生态系统的结构组成部分，有助于生物多样性和生态系统功能。然而，火灾严重程度对加利福尼亚内华达山脉地区（美国）的河流-河岸生态系统的影响尚未得到很好的描述，但对于有效地为火灾管理和政策提供信息至关重要。在与火灾严重程度配对的 12 个河段（一个高严重程度燃烧，一个低严重程度燃烧），野火后 2-15 年，河岸植物群落覆盖和组成或河流地貌特征没有显着差异。此外，在广泛而严重的环火之后的第一个夏天，河岸植被和河流地貌特性的变化很小。然而，在过去 81 年中，在我们的研究范围内，每个流域内都观察到了多次火灾事件对河流地貌指标的上游到下游影响，包括沉积物大小、嵌入度和河道几何形状。野火对河流-河岸植被和地貌特征在空间和时间上的不一致影响可能与火灾和降水以来的时间有关。嵌入性和通道几何，在我们的研究范围内。野火对河流-河岸植被和地貌特征在空间和时间上的不一致影响可能与火灾和降水以来的时间有关。嵌入性和通道几何，在我们的研究范围内。野火对河流-河岸植被和地貌特征在空间和时间上的不一致影响可能与火灾和降水以来的时间有关。